[From the U.S. Government Printing Office, www.gpo.gov]
Coastal Zone Information Center COASTAL ZONE INFORMATION CENTER POPULATION DYNAMICS AND LIFE HISTORY ASPECTS 0F MAJOR MARINE SPORTFISHES IN GEORGIA'S C0ASTAL WATERS Georgia Department of Natural Resources Coastal Resources Division March 1984 Contribution Series Number 38 QL 628 .G4 M8 1984 No.38 POPULATION DYNAMICS AND LIFE HISTORY ASPECTS OF MAJOR MARINE SPORTFISHES IN GEORGIA'S COASTAL WATERS by James L. Music, Jr. and John M. Pafford "MAL Z* VWVR#11R1WX cmr, Georgia Department of Natural Resources Coastal Resources Division 1200 Glynn Avenue Brunswick, Georgia 31523-9990 March 1984 This study was funded through the Federal Aid in Fish Restoration Act under Dingell-Johnson Project F-31, Georgia. Contribution Series Number 38 U . S . DEPARTMENT OF COMMERCE NOAA COASIAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE cm 63 C2"i r CHARLESTON SC 29405-2413 property Of CSC Library The Department of Natural Resources is an equal opportunity employer, and offers all persons the opportunity to compete and participate in each area of DNR employment regardless of race, color, sex, religion, __J national origin, age, physical or mental handicap, or other non-merit factors. FINAL REPORT STATE: GEORGIA PROJECT: F-31-6 PROJECT TYPE: SURVEY STUDY TITLE: Population Dynamics and Life History Aspects of Major Marine Sportfishes in Georgia's Coastal Waters. PERIOD COVERED: 1 July 1978 - 30 June 1983. STUDY OBJECTIVES: 1) To conduct a comprehensive study of seasonal movements and migration patterns of the eleven most important inshore marine recreational species of sportfishes. 2) To determine age and growth characteristics*, (time of annulus formation, size at various annuli, rates of growth, etc.) of the eleven target species. 3) To determine the food preferences and feeding habits of the target species and determine if seasonal and/or developmental changes in habits or diets occur. 4) To determine the reproductive characteristics (time of spawning, location of spawning, age at maturity, fecundity, etc.) of the target -0 species. ool ABSTRACT Various aspects of the life histories of 11 species of Georgia's inshore marine recreational sportfishes were investigated in the coastal waters of Glynn County from July 1978 through June 1982, to establish a data base to be used in making future management decisions concerning Georgia's marine recreational fishery. Species selected for study were spotted seatrout (Cynoscion nebulosus), weakfish (C. regaZis), red drum (Sciaenops ocelZatus), black drum (Pogonias cromis), southern flounder (Paralichthys lethostigma), summer flounder (P. dentatus), sheepshead (Archosargus probatocephalus), Atlantic cr(:i-aker (Micropogonias unduzatus), spot (Leiostomus xanthurus), southern kingfish (Menticirrhus americanus), and gulf kingfish (M. littoralis). Movements and migration patterns were determined through mark-recapture (tagging) studies; age and growth were determined through scale and otolith examination techniques; maturity and spawning information were determined through direct examination of the gonads; and feeding habits were determined through analyses of stomach contents. A summary of findings and management recommendations are also included. TABLE OF CONTENTS Page ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii LIST OF FIGURES . . . . . . . . . . . . . vii LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . xi INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1, METHODS AND MATERIALS . . . . . . . . . . . . . . . . . . . . . . . 8 RESULTS AND DISCUSSION Spotted Seatrout Movement and Migration . . . . . . . . . . . . . . . . . . . . 28 Length-Weight Relationship . . . . . . . . . . . . . . . . . . 49 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . . 49 Maturity and Spawning . . . . . . . . . . . . . . . . . . . . 60 Food Preference and Feeding Habits . . . . . . . . . . . . . . 84 Weakfish Movement and Migration . . . . . . . . . . . . . . . . . . . . 107 Length-Weight Relationship . . . . . . . . . . . . . . . . . . 112 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . . 115 Maturity and Spawning . . . . . . . . . . . . . . . . . . . . 117 Food Preference and Feeding Habits . . . . . . . . . . . . . . 129 Red Drum Movement and Migration . . . . . . . . . . . . . . . . . . . . 137 Length-Weight Relationship . . . . . . . . . . . . . . . . . . 144 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . . 148 Maturity and Spawning . . . . . . . . . . . . . . . . . . . . 154 Food Preference and Feeding Habits . . . . . . . . . . . . . . 161 Southern Flounder Movement and Migration . . . . . . . . . . . . . . . . . . . . 169 Length-Weight Relationship . . . . . . . . . . . . . . . . . . 175 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . . 175 Maturity and Spawning . . . . . . . . . . . . . . . . . . . . 181 Food Preference and Feeding Habits . . . . . . . . . . . . . . 187 iv TABLE OF CONTENTS (CONT'D.) Page RESULTS AND DISCUSSION (cont'd.) Summer Flounder Movement and Migration . . . . . . . . . . . . . . . . . . . 194 Length-Weight Relationship . . . . . . . . . . . . . . . . . 194 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 194 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 199 Food Preference and Feeding Habits . . . . . . . . . . . . . 202 Black Drum Movement and Migration . . . . . . . . . . . . . . . . . . . 208 Length-Weight Relationship . . . . . . . . . . . . . . . . . 215 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 218 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 225 Food Preference and Feeding Habits . . . . . . . . . . . . . 231 Sheepshead Movement and Migration . . . . . . . . . . . . . . . . . . . 240 Length-Weight Relationship . . . . . . . . . . . . . . . . . 246 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 246 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 249 Food Preference and Feeding Habits . . . . . . . . . . . . . 257 Atlantic Croaker Movement and Migration . . . . . . . . . . . . . . . . . . . 265 Length-Weight Relationship . . . . . . . . . . . . . . . . . 273 Age and Growth . . . . . . . . . . . . . . . . . ... . . . . 273 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 276 Food Preference and Feeding Habits . . . . . . . . . . . . . 285 Spot Movement and Migration . . . . . . . . . . . . . . . . . . . 294 Length-Weight Relationship . . . . . . . . . . . . . . . . . 298 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 298 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 308 Food Preference and Feeding Habits . . . . . . . . . . . . . 313 Southern Kingfish Movement and Migration . . . . . . . . . . . . . . . . . . . 320 Length-Weight Relationship . . . . . . . . . . . . . . . . . 324 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 328 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 332 Food Preference and Feeding Habits . . . . . . . . . . . . . 338 v TABLE OF CONTENTS (CONT'D.) Page RESULTS AND DISCUSSION (cont'd.) Gulf Kingfish ,Movement and Migration . . . . . . . . . . . . . . . . . . . 346 Length-Weight Relationship . . . . . . . . . . . . . . . . . 349 Age and Growth . . . . . . . . . . . . . . . . . . . . . . . 349 Maturity and Spawning . . . . . . . . . . . . . . . . . . . 353 Food Preference and Feeding Habits . . . . . . . . . . . . . 357 Miscellaneous Species . . . . . . . . . . . . . . . . . . . . . 359 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 364 RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 368 ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . 371 LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . 372 vi LIST OF FIGURES Figure Page 1. Study area within coastal waters of Glynn County, Georgia . . . . . . . . . . . . . . . . . . . . . . . . 9 2. Gillnetting activities . . . . . . . . . . . . . . . . . . 11 3. Fish "holding bag" showing float with suspended net . . . . 11 4. The Howitt and Floy internal anchor tags . . . . . . . . . 13 5. Insertion of the disk portion of the Howitt tag was accomplished by making a small incision through the ventral musculature of the abdomen and in- serting the disk lengthwise into the body cavity . . . 13 6. Floy tags were inserted on the left side just below the dorsal fin . . . . . . . . . . . . . . . . . . . . . 15 7. A double-tagged red drum showing typical appearance of tag streamers . . . . . . . . . . . . . . . . . . . 15 8. A tagged flounder showing typical appearance of Howitt streamer . . . . . . . . . . . . . . . . . . . . 16 9. Tag reward poster distributed throughout coastal counties to publicize tagging studies . . . . . . . . . 16 10. Carver laboratory press used to make scale impres- sions on cellutose plastic sheets . . . . . . . . . . . 19 11. Photographs showing various circuli patterns and formations used to identify scale annuli . . . . . . . . 21 12. Photograpb.of a typical scale showing direction of increment measurements . . . . . . . . . . . . . . . 22 13. Photographs of whole and sectioned otoliths . . . . . . . . 23 14. Isomet low speed saw used to section otoliths . . . . . . . 24 15. Length-weight relationship of spotted seatrout Wynoocion nebulosus) collected in Glynn County, 51 .0 Georgia from January 1979 through June 1982 . . . . . . vii '0 LIST OF FIGURES (CONT'D.) Figure Page 16. Length-age relationship of spotted seatrout (Cynoscion nebuZosus) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . . . . . 56 17. Cystic condition observed in seatrout ovaries that failed to resorb the egg mass . . . . . . . . . . . 82 18. Seatrout ovaries exhibiting unequal develop- ment and fluid laden ovaries . . . . . . . . . . . . . . . 82 19. Hermaphroditic spotted seatrout with gonads consisting primarily of testicular tissue . . . . . . . .83 20. Hermaphroditic spotted seatrout with gonads consisting primarily of ovarian tissue . . . . . . . . . 83 21. Comparison of fecundities for several populations of spotted seatrout (Cynoscion nebuZosus) . . . . . . . .85 22. Length-weight relationship of weakfish (Cynoscion regaZis) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . 116 23. Length-age relationship of weakfish (Cynoscion regalis) collected in Glynn County, Georgia . . . . . . . 119 24. Length-weight relationship of red drum (Sciaenops oceZZatus) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . 146 25. Empirical length/otolith ring relationship for red drum collected in Glynn County, Georgia . . . . . . . 149 26. Length-age relationship of red drum (Sciaenops ocellatus) collected in Glynn County, Georgia . . . . . . 152 27. Length-weight relationship of southern flounder (ParaZichthys lethostigma) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . 177 viii LIST OF FIGURES (CONT'D) Figure Page 28. Length-age relationship of southern flounder (ParaZichthys Zethostigma) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . 180 29. Length-weight relationship of summer flounder (Paralichthys dentatus) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 198 30. Length-weight relationship of black drum (Pogonias cromis) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . 217 31. Length-age relationship of black drum (Pogonias cromis ) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . . . . 223 32. Empirical length/otolith ring relationship for (Pogonias cromis) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . . . . 226 33. Gravid black drum (Pogonias cromis) with ovaries comprising approximately 43% of the body weight . . . . 232 34. Length-weight relationship of sheepshead (Archosargus probatocephaZus) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . 248 35. Length-age relationship of sheepshead (Archosargus probatooephaZus) col- lected in Glynn County, Georgia . . . . . . . . . . . . 251 36. Length-weight relationship of Atlantic croaker (Micropogonias unduZatus) collected in Glynn County, Georgia. . . . 274 37. Length-age relationship of Atlantic croaker (Micropogonias undulatus) collected in Glynn County, Georgia . . . . . . . . . .. . . . 279 .00 ix LIST OF FIGURES (CONT'D) Figure Page 38. Length-weight relationship of spot (Leiostomus xanthurus) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 301 39. Length-age relationship of spot (Leiostomus xanthurus) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . . . . . . . . 306 40. Length-weight relationship of southern king- fish (Menticirrhus =ericanus) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . .. . . . . . . . . 327 41. Length-age relationship of southern kingfish (Menticirrhus americanus) collected in Glynn County, Georgia . . . . . . . . . . . . . . . . . 331 42. Length-weight relationship of gulf kingfish (Menticirrhus ZittoraZis) collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . 350 LIST OF TABLES Table Page 1. Current state records for the 10 target species of fish as reported in pounds and ounces from the states where records were available . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Ranking of the use of different types of fishing gear and baits used by saltwater anglers by season for each species of fish . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Commercial landings for Georgia's major inshore recreational fisheries in thousands of pounds and thousands of dollars from 1960 through 1982 . . . . . . . . . . . . . . . . . . . . 5 4. List of scientific and accepted common names approved by the American Fisheries Society plus local names used by Georgia anglers for fishes investigated in Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 7 5. Description of net types . . . . . . . . . . . . . . . . . . . 10 6. Hjort's scale of maturities for classifying the reproduc- tively developing stages of sexual organs . . . . . . . . . . 27 7. Number tagged, number and percent recaptured, days at large and distance traveled for spotted seatrout, Cynoscion nebulosus, in 50 mm length groups . . . . . . . . . . . . . . 29 8. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for spotted seatrout, Cynoscion nebuZosus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 30 9. Number of spotted seatrout, Cynoscion nebuZosus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . ; . . . . . . . . . . . . . . 31 10. Number tagged and number and percent recaptured by species, tag type and season of release . . . . . . . . . . . . . . . . 33 11. Number and percent of tagged fish recaptured by recreational and commercial fishermen and project personnel . . . . . . . . 34 12. Number and average, minimum, and maximum lengths of tagged fish recaptured by recreational fishermen . . . . . . . . . . 35 13. Number tagged and recaptured in 50 mm length groups and percent of recaptures caught by recreational fishermen. . . . 36 xi LIST OF TABLES (CONT'D) Table Page 14. Number and percent of fish tagged and recaptured by sector. . 37 15. Number and percent of tagged fish by season and sector of recapture . . . . . . . . . . . . . . . . . . . . . . . . . . 39 16. Distance Georgia recreational fishermen traveled to reach the fishing area where tagged fish were recaptured . . . . . . 40 17. Number and percent of recreational recaptures by bait type used to catch tagged Georgia fish . . . . . . . . . . . . . . 41 18. Days at large and distance traveled for spotted seatrout, Cynoscion nebulosus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 42 19. List-of spotted seatrout recaptured greater than 50 km from the place of tagging . . . . . . . . . . . . . . . . . . 44 20. Seasonal movement of spotted seatrout, Cynoscion nebuZosus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 45 21. Number of recaptures and average and maximum distance traveled by season of recapture . . . . . . . . . . . . . . . 46 22. Comparison of tag recovery rates for several major fish movement investigations . . . . . . . . . . . . . . . . . . . 47 23. Comparison of distance in kilometers and nautical miles traveled by fish for several populations of spotted seatrout, Cynoscion nebulosus . . . . . . . . . . . . . . . . . . . . . 48 24. Length-weight equations for marine sportfish collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 50 25. Comparison of length-weight relationships for several popula- tions of spotted seatrout, Cynoscion nebuZosus . . . . . . . . 52 26. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebuZosus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 55 27. Length-age equations for marine sportfish collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 57 xii LIST OF TABLES (CONT'D) Table Page 28. Number, empirical and back-calculated total lengths, and growth increments by sex and age for spotted seatrout, Cynoscion nebulosus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 58 29. Comparison of mean back-calculated total lengths at age for several populations of spotted seatrout, Cynoscion nebuZosus. 59 30. Mean back-calculated total lenths for male spotted seatrout, Cynoscion nebuZosus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . 61 31. Mean back-calculated total lengths for female spotted seatrout, Cynoscion nebuZosus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . 62 32. Estimated mean daily growth of marine sportfish by sex for each year of life . . . . . . . . . . . . . . . . . . . . . . . 63 33. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebulosus, through age V for fish collected in the coastal waters of Glynn County, Georgia during 1979 . . . . . . 64 34. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebulosus, through age V for fish collected in the coastal waters of Glynn County, Georgia during 1982 . . . . . . 65 35. Number of spotted seatrout, Cynoscion nebuZosus, collected.by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 67 36. Average surface water temperature ( 0C) by sector and month in bi-monthly increments for Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . 69 37. Average surface water salinities (0/oo) by sector and month in bi-monthly increments for the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 70 38. Stages of gonadal development for spotted seatrout, Cynoscion nebuZosus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 39. Stages of gonadal development for spotted seatrout, Cynoscion nebuZosua, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 73 xiii LIST OF TABLES (CONT'D) Table Page 40. Number and percent of fish showing advanced gonadal development during various moon phases by species and sex for fish collected in Glynn County, Georgia from January 1979 through June 1982. . . 75 41. Sex ratio for marine sportfishes iri 50 mm length groups for fish collected in the coastal,waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . 77 42. Number and percent of female versus male spotted seatrout, Cynoscion nebulosus, by salinity gradient and month for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 43. Number and percent of females versus males by salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . 79 44. Number and percent of various ovarian conditions for spotted seatrout, Cynoscion nebulosus, by estuarine system for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 45. Estimated fecundity for 12 spotted seatrout, Cynoscion nebulosus, collected in the coastal waters of Glynn County, Georgia during May and June of 1980 . . . . . . . . . . . . . . . . . . . . . . . 86 46. Number and percent of empty stomachs versus those containing food for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 88 47. Stomach contents of spotted seatrout, Cynoscion nebulosus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 48. The 10 most frequently occurring food items found in the stomachs of spotted seatrout, Cynoscion nebuZosus., by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . 93 49. Number and percent of spotted seatrout, Cynoscion nebuZosus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . 96 50. Number and percent of stomachs containing food versus empty stomachs by species and surface water temperature for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 xiv W LIST OF TABLES (CONT'D) Table Page 51. Number and percent of stomachs containing food versus empty stomachs for each species by moon phase for fish collected 98 Ir in Glynn County, Georgia from January 1979 through June 1982. 52. Seasonal occurrence of organisms collected with trawl from the coastal waters of Glynn County, Georgia from January 1979 through June 1980 . . . . . . . . . . . . . . . . . . . . . 100 53. occurrence of organisms collected by trawling by sector in the coastal waters of Glynn County, Georgia from January 1979 through June 1980 . . . . . . . . . . . . . . . . ... . . . 103 54. The 15 most commonly occurring organisms belonging to the classes Pisces and Crustacea collected in 216 samples made with a three meter trawl . . . . . . . . . . . . . . . . . . . . 106 55. Number tagged, number and percent recaptured, days at large and distance traveled for weakfish, Cynoscion regaZis, in 50 mm length groups . . . . . . . . . . . . . . . . . . . . . . . . . 108 56. Total number tagged and the return rates for Howittand Floy tags and for tags combined in 50 mm length groups for weakfish, Cynoscion regaZis-, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . 109 57. Number of weakfish, Cynoscion regalis, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 110 58. Days at large and distance traveled for weakfish, Cynoscion regaZis, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 113 59. Seasonal movement of weakfish, Cynoscion regaZis, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 114 60. Mean back-calculated total lengths for weakfish, Cynoscion regaZis, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 118 61. Number, empirical and back-calculated total lengths and growth increments by sex and age for weakfish, Cynoscion regaZis, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . 120 xv 14 LIST OF TABLES (CONT'D) Table Page 62. Number of weakfish, Cynoscion regalis, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 12'2 63. Ichthyoplankton collected by month in Glynn County, Georgia from January 1979 through May 1979 . . . . . . . . . . . . . . 123 64. Stages of gonadal development for weakfish, Cynoscion regalis, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. . . 125 65. Stages of gonadal development for weakfish, Cynoscion regazis, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 128 66. Number and percent of female versus male weakfish, Cynoscion regalis, by salinity gradient and month for fish collected in Glynn County, Georgia from January 1979 through June 1982 130 67. Stomach contents of weakfish, Cynoscion regalis, collected in Glynn County, Georgia from January 1979 through June 1982 . . . 131 68. The 10 most frequently occurring food items found in the stomachs of weakfish, Cynoscion regaZis, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 133 69. Number and percent of weakfish, Cynoscion regaZis, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 136 70. Number tagged, number and percent recaptured, days at large and distance traveled for red drum, Sciaenops oceZZatus, in 50 mm length groups . . . . . . . . . . . . . . . . . . . . . . 138 71. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for red drum, Sciaenops ocellatus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . 139 72. Number of red drum, Sciaenops ocelZatus, tagged by length, group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . 140 xvi LIST OF TABLES (CONT'D) Table Page 73. Days at large and distance traveled for red drum, Sciaenops ocellatus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 143 74. Seasonal movement of red drum, Sciaenops ocellatus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 145 75. Comparison of total length-weight relationships for several populations of red drum, Sciaenops ocelZatus . . . . . . . . . 147 76. Mean back-calculated total lengths for red drum, Sciaenaps oceZZatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 151 77. Number, empirical and back-calculated total lengths, and growth increments by sex and age for red drum, Sciaenops ocelZatus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 153 78. Comparison of total lengths at age for several populations of red drum, Sciaenops ocellatus . . . . . . . . . . . . . . . . . 155 79. Number of red drum, Sciaenopa ocellatus, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . 158 80. Stages of gonadal development for red drum, Sciaenops ocella- tus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159 81. Stages of gonadal development for red drum, Sciaenops oceNa- tus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . 160 82. Stomach contents of red drum, Sciaenops ocelZatus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 83. The 10 most frequently occurring food items found in the stomachs of red drum, Sciaenops ocelZatus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 165 xvii LIST OF TABLES.(coNT D.), Table Page 84. Number and percent of red drum, Sciaenops oceZZatus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 167 85. Number tagged, number and percent recaptured, days at large and distance traveled for southern flounder, - ParaZichthys Zethostigma, in 50 mm length groups . . . . . . . 170 86. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for southern flounder, ParaZichthys Zethostigma, tagged in Glynn County, Georgia from January 1979 through June 1982 17, 87. Number of southern flounder, Paralichthys lethostigma, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . ... . . . . . . . 172 88. Days at large and distance traveled for southern flounder, Paralichthys lethostigma, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 174 89. Seasonal movement of southern flounder, ParaZichthys Zethostigma, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 176 90. Mean back-calculated total lengths for southern flounder, ParaZichthys Zethostigma, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 91. Number, empirical and back-calculated total lengths, and growth increments by sex and age for southern flounder, ParaZichthys lethostigma, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 92. Number of southern flounder, ParaZichthys Zethostigma, collected by month, sex and reproductive stage for the 184 period January 1979 through June 1982 . . . . . . . . . . . . 93. Stages of gonadal development for southern flounder, ParaZichthys lethostigma, by month, sex and salinity gradient for fish collected in Glynn County, Georgia 185 from January 1979 through June 1982 . . . . . . . . . . . . . xviii LIST OF TABLES (CONT'D) Table Page 94. Stages of gonadal development for southern flounder, Paralichthys lethostigma, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 186 95. Stomach contents of southern flounder, ParaLichthys Zethostigma, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . 188 96. Number and percent of southern flounder, ParaZichthys lethostigma, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through Jurie 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 97. The 10 most frequently occurring food items found in the stomachs of southern flounder, Paralichthys tethostigma, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 191 98. Number tagged, number and percent recaptured, days at large and distance traveled for summer flounder, Para- Zichthys dentatus, in 50 mm length groups . . . . . . . . . . 195 99. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for summer flounder, ParaZichthys dentatus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 100. Number of summer flounder, Paralichthys dentatus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 197 101. Mean back-calculated total lengths for summer flounder, ParaZichthys dentatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200 102. Stomach contents of summer flounder, ParaLichthys dentatus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . ... . . . . . . . . . . . 203 '0 xix LIST OF TABLES (CONT'D) Table Page 103. The 10 most frequently occurring food items found in the stomachs of summer flounder, Paralichthys dentatus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 204 104. Number and percent of summer flounder, Paralichthys dentatus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207 105. Number tagged, number and percent recaptured, days at large and distance traveled for black drum, Pogonias cromis, in 50 mm length groups . . . . . . . . . . . . . . . 209 106. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for black drum, Pogonias cromis, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 210 107. Number of black drum, Pogonias cromis, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211 108. Days at large and distance traveled for black drum, Pogonias cromis, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . 214 109. Seasonal movement of black drum, Pogonias cromis, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . 216 110. Comparison of total length-weight relationships for several populations of black drum, Pogonias cromis . . . . . 219 111. Mean back-calculated total lengths for black drum, Pogonias cromis, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 112. Number, empirical and back-calculated total lengths, and growth increments by sex and age for black drum, Pogonias cromis, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . 222 xx LIST OF TABLES (CONT'D) Table Page 113. Total lengths and number of otolith rings for all black drum greater than 400 mm . . . . . . . . . . . . . . . . . . 224 114. Number of black drum, Pogonias cromis, collected by month, sex and reproduction stage for the period January 1979 through June 1982 . . . . . . . . . . . . . . . 228 115. Stages of gonadal development for black drum, Pogonias cromis, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 229 116. Stages of gonadal development for black drum, Pogonias cromis, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . 230 117. Stomach contents of black drum, Pogonias cromis, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 233 118. The 10 most frequently occurring food items found in the stomachs of black drum, Pogonias cromis, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 237 119. Number and percent of black drum, Pogonias cromis, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . 239 120. Number tagged, number and percent recaptured, days at large and distance traveled for sheepshead, Archosargus probatocephalus, in 50 mm length groups . . . . . . . . . . . 241 121. Total number tagged and the return rates for Howitt and Floy tags and for tags combined in 50 mm length groups for sheepshead, Archosargus probatocephaZus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 122. Number of sheepshead, Archosargus probatocephalus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 243 Xxi LIST OF TABLES (CONT'D) Table Page 123. Days at large and distance traveled for sheepshead, Archosargus probatocephalus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 245 124. Seasonal movement of sheepshead, Archosargus probato- cephaZus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 247 125. Mean back-calculated total lengths for sheepshead, Archosargus probatocephalus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 250 126. Number, empirical and back-calculated total lengths, and growth increments by sex and age for sheepshead, Archosargus probatocephaZus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June.1982 . . . . . . . . . . . . . . . . . . . . . . 252 127. Number of sheepshead, Archo8argus probatocephalus, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . 254 128. Stages of gonadal development for sheepshead, Archo- sargus probatocephaLus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 255 129. Stages of gonadal development for sheepshead, Archo- sargus probatocephaZus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 256 130. Estimated fecundity for 12 sheepshead, Archosargus probatocephaZus, collected approximately 21 miles south- east of St. Simons Island, Georgia during April, 1982 . . . . 258 131. Stomach contents of sheepshead, Archosargus probato- cephaZus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 259 132. The 10 most frequently occurring food items found in the stomachs of sheepshead, Archosargus probatocephatus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 262 xxii LIST OF TABLES (CONT'D) Table Page 133. Number and percent of sheepshead, Archosargus probato- cephaZus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 134. Number tagged, number and percent recaptured,, days at large and distance traveled for Atlantic croaker, Micropogonias unduZatus, in 50 mm length groups . . . . . . . . 267 135. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for Atlantic croaker, Micropogonias unduZatus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . 268 136. Number of Atlantic croaker, Micropogonias unduZatus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 269 137. Days at large and distance traveled for Atlantic croaker, Micropogonias unduZatus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . 271 138. Seasonal movement of Atlantic croaker, Micropogonias unduZatus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . 272 139. Comparison of total length-weight relationships for several populations of Atlantic croaker, Micropogonias unduZatus . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 140. Mean back-calculated total lengths for Atlantic croaker, Micropogonias undulatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through 1982 . . . . . . . . . . . . . . . . . . . . . . . 277 141. Number, empirical and back-calculated total lengths, and growth increments by sex and age for Atlantic croaker, Micropogonias unduZatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . .. . . . . . . . . . 278 :0 142. Comparison of lengths at age for several populations of Atlantic croaker, Micropogonias unduLatus . . . . . . . . . 280 xxiii LIST OF TABLES (CONT'D) Table Page 143. Number of Atlantic croaker, Micropogonias unduLatus, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . 282 144. Stages of gonadal development for Atlantic croaker, Micropogonias undulatus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 283 145. Stages of gonadal development for Atlantic croaker, Micropogonias undulatus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . 284 146. Stomach contents of A tlantic croaker, Micropogonias undutatus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . ... . . . . . . 286 147. The 10 most frequently occurring food items found in the stomachs of Atlantic croaker, Micropogonias undulatus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . 289 148. Number and percent of Atlantic croaker, Micropogonias unduLatus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 149. Number tagged, number and percent recaptured, days at large and distance traveled for spot, Leiostomus xanthurus, in 50 mm length groups . . . . . . . . . . . . . . 295 150. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for spot, Leiostomus xanthurus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . 296 151. Number of spot, Leiostomus xanthurus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . 297 xxiv LIST OF TABLES (CONT'D) Table Page 152. Days at large and distance traveled for spot, Leiostomus xanthurus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 299 153. Seasonal movement of spot, Leiostomus xanthurus... tagged in the coastal waters of Glynn County, Geor gia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 300 154. Comparison of total length/weight relationships for several populations of spot, Leiostomus xanthurus . . . . . . . 302 155. Mean back-calculated total lengths for spot, Leiostomus xanthurus, collected in the coastal waters of Glynn County, Georgia from,january 1979 through June 1982 . . . . . . 304 156. Number, empirical and back-calculated total lengths, and growth increments by sex and age for spot, Leiostomus xanthurus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . 305 157. Number of spot, Leiostomus xanthurus, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . . . . . . . I . . . . . . 309 158. Stages of gonadal development spot, Leiostomus xanthurus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through 310 June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . 159. Stages of gonadal development for spot, Leiostomua xanthurus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 311 160. Stomach contents of spot, Leiostomus xanthurus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . 314 161. The 10 most frequently occurring food items found in the stomachs of spot, Leiostomus xanthurus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 316 xxv LIST OF TABLES (CONT'D) Table Page 162. Number and percent of spot, Leiostomus xanthurus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 319 163. Number tagged, number and percent recaptured, days at large and distance traveled for southern kingfish, Menticirrhus americanus, in 50 mm length groups . . . . . . . 321 164. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for southern kingfish, Menticirrhus =ericanus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 322 165. Number of southern kingfish, Menticirrhus amemcanus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 323 166. Days at large and distance traveled for southern kingfish, Menticirrhus americanus, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 325 167. Seasonal movement of southern kingfish, Menticirrhus americanus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . 326 168. Mean back-calculated total lengths for southern kingfish, Menticirrhus americanus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . 329 169. Number, empirical and back-calculated total lengths, 4'nd growth increments by sex and age for southern kingfish, Menticirrhus americanus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 330 170. Number of southern kingfish, Menticirrhus wnericanus, collected by month, sex and reproductive stage for the period of January 1979 through June 1982 . . . . . . . . . . . 333 171. Stages of gonadal development for southern kingfish, Menticirrhus conericanus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 334 xxvi LIST OF TABLES (CONT'D) Table Page 172. Stages of gonadal development for southern kingfish, Menticirrhus americanus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 337 173. Stomach contents of southern kingfish, Menticirrhus americanus, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . 339 174. The 1.0 most frequently occurring food items found in the stomachs of southern kingfish, Menticirrhus conericanus, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1.982 . . . . . . . . . 342 175. Number and percent of southern kingfish, Menticirrhus americanus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . ... . . . . . . . . . . . . . . . . . . . . . . . . 345 176. Total number tagged and the return rates for Howitt and Floy tags and for,tags combined in 50 mm length groups for gulf kingfish, Menticirrhus littoraZis, tagged in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347 177. Number of gulf kingfish, Menticirrhus Zittoralis, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . 348 178. Mean back-calculated total lengths for gulf kingfish, MenticirAus ZittoraZis, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . 351 179. Number, empirical and back-calculated total lengths, and growth increments by sex and age for gulf kingfish, Menticirrhus Zittoralis, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352 180. Number of gulf kingfish, Menticirrhus Zittoralis, collected by month, sex and reproductive stage for the period January 1979 through June 1982 . . . . . . . . . . 354 xxvii LIST OF TABLES (CONT'D) Table Page 181. Stages of gonadal development for gulf kingfish, Menticirrhus littoralis, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . 355 182. Stages of gonadal development for gulf kingfish, Menticirrhus Zittoralis, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . 356 183. Stomach contents of gulf kingfish, Menticirrhus littoraZis, collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . 358 184. The 10 most frequently occurring food items found in the stomachs of gulf kingfish, Menticirrhus littoraZis, by season and by sector for fish collected in Glynn County, Georgia from January 1979 through June 1982 . . . . . . . . . . . . . . . . . . . . 360 185. Number tagged, number and percent recaptured and days at large and distance traveled for fish tagged in addition to the target species . . . . . . . . . . . . . . . . 363 xxviii INTRODUCTION Georgia is unique among other coastal states in both its fishery resources and its user groups. The vast expanse of saltmarsh vegetation and the associated network of tidal creeks and rivers create an ideal nursery system for countless species of fish and invertebrates. Con- sequently,these areas harbor excellent opportunities for coastal anglers who prefer fishing in protected inshore waters. Georgia is also unique among other coastal states in that the finfish fishery is practically devoid of competition from commercial fishing operations in inshore waters, giving the recreational fishing community complete access to the resource. Georgia has no commercial pound netting or haul seining, and gill- netting is prohibited except for shad and sturgeon during the open season for these species. Furthermore, only shad or sturgeon may be kept during gillnetting activities,and any other species captured must be immediately released unharmed. Considering the absence of competi- tion from commercial interests, Georgia's recreational hook and line fishermen literally have their cake and are able to eat it too. Georgia's offshore recreational fishing is focused primarily around nine artificial reefs constructed in the early 1970's, around the scat- tered patches of "live bottom" areas such as the Gray's Reef National Marine Sanctuary off Sapelo Island, and those patches farther offshore from Savannah, St. Catheripes Island and Brunswick. Those fishermen with larger offshore fishing boats quite often venture out to the Gulf Stream approximately 80 miles offshore. Both demersal groundfishes and migratory pelagics occur in fair numbers in offshore waters along Georgia's coast. Dominant offshore bottom fishes include seabasses, snappers, groupers, porgies, grunts and sheepsheads, and major pelagic species include bluefish, king and Spanish mackerel, cobia, greater amberjack, dolphin, Atlantic sailfish, white and blue marlin, and swordfish. The inshore recreational fishery is centered primarily in the sounds and major rivers during the warmer months and in the rivers and creeks during the colder months. Surf fishing is limited, and takes place almost exclusively during warm months and during fair weather, and most of the prime surf fishing areas are accessible only by boat. Most inshore fishing effort is directed toward sciaenid fishes with most effort focused on the spotted seatrout. Other fishes actively pur- sued include red and black drum, flounders, kingfish or "whiting", croakers, sheepshead, and bluefish. Generally, spots are relatively small and very little effort is directed toward them. Excellent opportunities are afforded the Georgia inshore angler as there are currently no saltwater license fees, no creel or size limits, and the fish are comparable in size with those of other states. State records comparing Georgia fish with record fish from other states are presented in Table 1. The particular fish species being sought and the specific method employed to capture them changes seasonally, but good inshore fishing can generally be found throughout the year. The primary techniques employed by Georgia anglers and the baits used to catch each species are presented in Table 2. Although there is no legal gillnet fishery in Georgia other than for shad and sturgeon, a variety of fish are landed and sold annually by other methods. Many groundfish are sold as by-catch from commercial shrimp fishing operations. This by-catch consists primarily of flounders, weakfish or "summer trout", kingfish or`whiting", croakers and spots. However, two of the most popular sportfish species, spotted seatrout and red drum, are rarely taken by trawlers. In addition to by-catch sales many fish are caught and sold annually by hook and line fishermen pos- sessing personal commercial fishing licenses and who elect to sell all or a portion of their catches. The spotted seatrout is the primary target of inshore anglers and is consequently the species most frequently sold by hook and line fishermen. However, most other species are sold as well. Although Georgia's commercial finfisb landings records are not recorded by commercial gear type, annual commercial landings of the major inshore recreational species since 1960 are presented in Table 3. 2 Table I . Current state records for the 10 target species of fish as reported in pounds and ounces from the states where records were available. Spotted Weak- Red Southern Summer Black Sheeps- Atlantic Northern Sou, -rn Go I I seatrout f ish Drum Flounder Flounder Drum head croaker Spot Kingfish EjpjLL@ i @J_n, f i@sjl i Lb Oz z Lb Oz Lb Oz Lb Oz Lb Oz Fb Oz Ub--Oz -Yb--Oz -Lb Oz Lb Oz Lb Rhode Island - - - - - - 17 8 - - - - - - - - - - - - - - New York 17 14 - - - - 22 7 - - - - - - - - - - - - - - New Jersey 11 2 17 8 51 9 - - 19 12 102 12 - - 5 8 - - - - - - - - Delaware - - 16 10 75 0 - - 17 15 115 0 - - 5 4 - - 4 0 - - - - Maryland 16 8 16 8 74 6 - - 17 0 103 8 - - 6 3 2 0 2 8 - - - Virginia 16 0 - - - - - - - - - - - - - - - - - - - - - North Carolina 12 4 14 14 90 0 - - 20 8 84 0 16 8 5 0 1 11 3 8 - - - South Carol ina 11 13 11 13 75 0 17 6 3 8 89 0 15 4 4 9 1 1 - - 2 10 - (',uor,, i a 9 7 6 8 45 0 15 2 - - 81 0 13 3 5 12 - - - - 2 12 - Alabama 12 4 - - 43 0 *13 3 26 4 9 7 - - - - *2 8 (composite) (composite) Mississippi 10 6 - - 44 0 *9 8 42 0 10 4 - - - - *1 11 (composite) (composite) Louisiana 12 6 - - 56 8 *12 2 77 0 14 12 8 0 - - (composite) NOTE: A dash (-) denotes Incomplete or unavailable records. An asterisk (*) denotes a composite of two or more species. Table 2 . Rankin$ of the use of different types of fishing gear and baits used by saltwater anglers by season tor eaen species ot tisn. kw- winttr; Sp- Spring; Su" Sumer; F- Fall). TERMIKAL GEAR RAIT TYPE Use V Bottom 2/ Float I/AFR-ficial Live Dead Minnows Cut bait Crab Oysters SPECIES Rating Rig Ris Lure Shrimp Shrimp and fish (fish) and fiddlers and clams Sqvid Spotted seatrout Primary Sp'Su'F W'Sp Sp,Su,F Secondary Sp,Su,F W Su,F W Su,F Sp,Su.F Weakfish Primary W'SP'Su'F W'Sp W,Sp,Su,F Secondary W'SP.Su.F SP'Su'F Sp,Su,F Red drum (juvenile) Primary Sp,Su,F Sp.Su,F Sp.Su,F Secondary Sp,Su.F F.W,Sp S,F Sp.Su,F Sp,Su.F Su,F Su,F led drum (Bulls) Primary Sp'Su'F Sp.Su,F Sp,Su,F Secon"ry Sp.Su,F Sp,Su,F Sp,Su.F Sp,Su,F Sp,Su.F Southern flounder Primary Sp'Su'F Su'F Su'F Sp'Su'F Secondary F.W Su,F Summer flounder Primary Sp,Su,F Su,F Sp,Su.F Secondary F Su'F Su.F Slack drum (Juvenile) Primary Sp'Su.F Sp.Su.F Sp,Su,F Secondary SPISU.F Sp,Su.F Sp,Su.F Black drum (Bulls) Primary Sp.Su1F Sp,Su,F Secon"ry SP.Su.F Sp Sp Sp,Su,F Sbeepshead Plrimry Sp'Su'F Sp'Su'F Sp,Su,F Secondary Sp'SU'F SV,Su.F Sp,Su,F ktiantic croaker Primary Sp'Su'F a Sp,Su,F a Secondary SP'Su'F SP,Su.F Sp,Su,F Spot Primary Sp,Su,F Sp,Su,F Secondary SP'Su'F Sp,Su,F Sp'Su.F Southern kingfish Primary SP.Suj Sp'Su.F Secon"ry 8p'Su'F Sp,Su,F SP'Su'F -1/ Conventional surf or bottom rig. 2/ Adjustable depth float rig. 3/ Lurea, bucktails and plastic tail jigs. This technique is seldom used by Georgia anglers. Alk I F Table 3. Commercial landings for Georgia's major inshore recreational fisheries In thouqands of pounds and thousands of dollars from 1960 through 1982. '00 Spotted Red Flounder Black Atlantic Kingfish Seatrout Weakfish Drum Compo!@,LLe Drum-- @hte-L,@ead Croaker Svit- LVAli-t ing) lb. lb. lb. $ lb. $ lb. $ 1-h-. lb. lb. 1960 (1) (1) 2/ (1) (1) 39 4 3 (1) - - (1) (1) (1) (1) 282 23 1961 2 1 1 (1) 37 4 1 (1) - - - - (1) (1) 247 20 1962 1 (1) 27 3 - - - - 1 (1) 4 (1) 166 13 1963 5 2 (1) 22 3 1 (1) - - 1 (1) 4 1 125 it 1964 2 1 - 6 (1) 1 (1) (1) (1) (1) (1) 3 (1) 91 9 1965 9 3 2 (1) 51 5 2 (1) 1 (1) 2 (1) 11 1 253 28 1966 3 1 1 (1) 3 (1) 35 6 1 (1) 1 (1) 5 1 5 1 146 19 1967 7 2 (1) (1) 6 1 22 4 2 (1) 1 (1) 6 (1) 11 1 187 19 1968 2 1 (1) (1) 6 1 23 5 1 (1) (1) (1) - - 2 (1) 123 15 1969 3 1 1 (1) 3 1 28 5 (1) (1) (1) (1) 2 (1) 2 (1) 111 13 Ln 1970 10 2 (1) (1) 2 (1) 37 6 7 1 1 (1) 9 (1) 9 1 146 15 1971 16 4 - - 1 (1) 51 9 (1) (1) 1 (1) (1) (1) 6 1 165 19 1972 26 6 - - 3 1 63 13 2 (1) 1 (1) 2 (1) 33 3 200 25 1973 27 10 (1) (1) 4 1 77 18 5 1 5 1 is 1 34 4 217 33 1974 16 6 - - 3 1 74 16 3 1 7 1 8 1 16 2 190 30 1975 31 13 2 (1) 10 1 9() 24 4 1 6 1 4 1 9 1 222 41 1976 30 15 - - 7 2 113 35 2 1 6 1 14 2 18 3 227 48 1977 16 9 1 (1) 5 2 82 28 1 (1) (1) (1) 7 2 7 1 162 38 1978 2 1 (1) (1) (1) (1) 96 41 - - - - (1) (1) (1) (1) 282 62 1979 5 4 1 (1) (1) (1) 112 49 - - - - 19 6 (1) (1) 171 54 1980 4 3 (1) (1) (1) (1) 76 33 1 (1) 1 (1) 5 1 1 (1) 235 79 1981 (1) (1) (1) (1) (1) (1) 56 28 (1) (1) (1) (1) 1 (1) 8 3 202 85 1982 5 5 1 (1) (1) (1) 80 34 - - (1) (1) 2 1 (1) (1) 381 151 Parentheses Indicate less than 500 lb. or $500. 21 A dash (-) indicates none reported. NOTE: Commercial landings include species caught and sold by recreational anglers. With the current population expansion along the coast and its accompanying demand on the finfish stocks now and in the future, fishery managers need technical information on the life histories of these sport- fishes to facilitate proper management decisions for regulating the harvest. In order to gain much needed baseline data on the inshore fishery the Georgia Department of Natural Resources initiated this study in July 1978 to analyze certain life history aspects of the 41 major species caught by Georgia's inshore anglers. Data were collected on movement and migration, age and growth, feeding habits, maturity and spawning as well as other information related to Georgia's inshore sport- fishery as it exists today. The local names, accepted common names and scientific names of these inshore sportfish targeted for study appear in Table 4. Information is presented in this paper.to be of benefit to anglers and laymen as well as to fishery managers and the scientific community. 6 Table 4. List of scientific and accepted common names approved by the American Fisheries Society plus local names used by Georgia anglers for fishes investigated in Georgia from January 1979 through June 1982. SCIENTIFIC NAME ACCEPTED COMMN NAME LOCAL NAMES C@noscion nebuloaus (Cuvier) - Spotted seatrout *Trout Spotted trout Winter trout Speckled trout **Gator trout Cynoecian regalia (Bloch and Schneider) Weakfish *Su=mer trout Yellowmouth trout Scidenops ocellatus (Linnaeus) Red drum *Bass Channel bass Spot-tail bass School bass Red drum Red bass **Stag bass Pogoniaa c7"niB (Linnaeus) Black drum *Drum Black drum Puppy drum Micropogoniae undulatus (Linnaeus) Atlantic croaker Croaker **Virginia croaker Manticirrhus, wwricanua (Linnaeus) gouthern kingfish *Whiting **Bull whiting Menticirrhue littoralis (Holbrook) Gulf kingfish *Beach whiting Silver whiting Leioatmw xanthurue Lacepede Spot Spot Paralichthys lethoetigna Jordan and Gilbert Southern flounder *Flounder Winter flounder Paralichthys dentatue (Linnaeus) Summer flounder Mounder Suesser flounder Archosaryus probatocephalue (Walbaum) Sheepshead Sheepshead Most co mmo nly used local name. Term used for large specimens. METHODS AND MATERIALS The coastal area of Glynn County lies within the western-most portion of the South Atlantic bight (Figure 1). Glynn County is in the center of the Georgia coast and is typical of the entire Georgia coast in that it has a four to six mile expanse of marshland separating the mainland from the outer barrier islands. This band of marshland comprises approximately 159 thousand hectares (393 thousand acres) with nearly 116 thousand hect- ares (286 thousand acres) covered by a single species of marsh grass, known as saltmarsh or smooth cordgrass, Spartina aZternifZora Loisel (Spinner, 1969). The coastal marshes are subjected twice daily to tides of approxi- mately the same height, normally ranging from 1.8 to 2.4 meters (6 to 8 feet). Greatest tidal amplitude occurs during the fall when tides often reach or exceed 3 meters (9 feet). The grain size of sediments in the .marsh range from clay to fine sand, and the marsh soils are normally neutral to slightly alkaline (Johnson et al.,1974). The study area was divided into four sectors for comparative purposes. The four sectors included: 1) creek sector, consisting of the smaller creeks and rivers usually located in the upper portion of the estuary; 2) sound sector, consisting of the sound and adjacent major rivers; 3) beach sector, consisting of the beaches and outer bars and shoals, and 4) offshore sector, consisting of offshore waters beyond the outer bars. Sampling in the offshore sector was limited to collection of specimens for age and re- production analyses. The fish collected for tagging and laboratory analyses were captured through the use of gill nets, trammel nets, seines, traps, cast nets, trawls, spear guns and conventional hook and line gear. The various mesh sizes of net types utilized are listed in Table 5. Fish collected for tagging were taken directly from the nets and placed in a holding bag suspended in ambient water (Figures 2 and 3). Before tagging, all fish were individually inspected for injuries, and 8 .. mr-4mp AL ab 41A NA 0 1 7. SEA qNSWjq ISLAND Norm REEF A#OIV.9 8040 V '.. JEKYLL ISLAND 0 1 4 NAUTICAL MILES ST. ANDREW SOUND A REEF CUMBERLAND ISLAND Figure 1. Study area within coastal waters of Glynn County, Georgia. 9 Table 5. Description of net types. Gear Type Gear Specifications Gill Net (1@ in.) Stretched mesh, 1@ in.; meshes deep, 50; twine, #139 monofilament; net length, 10 yd.; leadline, 50 lb. Samson; floatline, @ in. polyethylene corkline. Gill Net (2 in.) Stretched mesh, 2 in.; meshes deep, 40; twine, #177 monof.ilament; net length, 35 yd.; leadline, 50 lb. Samson; floatline, ;5 in. polyethylene corkline. Gill Net (2-7/8 in.) Stretched mesh, 2-7/8 in.; meshes deep, 50; twine, #208 monofilament; net length, 200 yd.; leadline, 75 lb. Dura; floatline, 2-3/8 in. polyfoam floats on 3/8 in. polyethylene line. Gill net (311 in.) Stretched mesh, A in.; meshes deep, 25; twine, #208 monofilament; net length, 165 yd.; leadline, 85 lb. Dura; floatline, ;I in. poly- ethylene corkline. Gill Net (4-5/8 in.) Stretched mesh, 4-5/8 in.; meshes deep, 35; twine, #208 monofilament; net length, 200 yd.; leadline, 85 lb. Dura; floatline, 3 in. poly- foam floats on 3/8 in. polyethylene line. Trammel Net Stretched mesh, 2 in. inner panel and 8 in. outer panels; meshes deep, 60 inner panel and 8 outer panel; twine, #209 nylon inner panel and #9 nylon outer panel; net length, 100 yd.; leadline, 75 lb@. Samson; floatline, #125 plastic floats (1 x 4 in.). Trawl One 40 ft. flat ottef trawl with 1-7/8 in. stretched mesh webbing and 1-3/4 in. stretched mesh bag with 48 in. doors. Trawl One 10 ft. flat otter trawl with lit in. stretched mesh webbing and I;x in. stretched mesh bag with 30 in. doors. Cast Net Seven foot with 2 in. stretched mesh webbing. Cast Net Six foot with 1 in. stretched mesh webbing. Seine (1/8 in.) Mesh, 1/8 in. braided with nylon twine; net length, 12 ft.; net depth, 4 ft. Seine Wi in.) Stretched mesh, VI in.; meshes deep, 50; twine, #208 monofilament; net length, 33 yd. 10 eq lima "Rim Figure 2. Gillnetting activities. -W "Or- k@q AL k fe. Aft, IL Figure 3. Fish "holding bag" showing float with suspended net. only active, apparently unharmed fish were measured and tagged. Most creel size specimens were tagged with internal anchor tags manufactured by the Howitt Plastics Company of Molalla, Oregon. Small fish (<160 mm) were tagged with Floy FD-68BC internal anchor tags manufactured by Floy Tag and Manufacturing, Inc. of Seattle, Washington. A total of 116 creel size fish were double tagged with both Howitt and Floy tag types in order to make tag retention comparisons. Tagged fish were released in the area of capture. The internal anchor portion of the Howitt tags were oval pla stic disks measuring 6 x 25 x 0.8 mm (.25 X 1 X .03 in.) with a 1.9 mm (0.76 in.) hole in the center of the disk. The streamer portion of the tag was con- structed from 2 mm diameter vinyl spaghetti tubing cut in 75 mm lengths. Streamers were heated on one end and flattened to form a nailhead shape. The streamer was then passed through the hole in the tag disk and locked in place (Figure 4). Each tag in the first set of 5,000 tag disks was marked on both sides. One side was marked: "REWARD, SEND TAG, DATE, EXACT LOCATION, LENGTH, HOW CAUGHT AND BAIT USED TO:", and the other with "COASTAL RESOURCES DIVISION, 1200 GLYNN AVENUE, BRUNSWICK, GEORGIA 31523" and included the tag serial number. Each tag in the second set of 5,000 tag disks was marked identically to first set except "LENGTH" was deleted and "PHONE" added. This change was made because many of the lengths re- ported by those catching tagged fish were reported as approximate or estimated lengths whi ch could not be used for growth measurement. Tele- phone numbers were included to obtain more accurate information than was reported from tags returned in the mail. Insertion of the Howitt tag was accomplished by making a small in- cision, approximately 8 mm in length, through the ventral musculature of the abdominal wall midway between the left pelvic fin and anal vent (Figure 5). The tag disk was inserted lengthwise into the body cavity with the streamer portion protruding from the ventral body wall (Beau- .mariage and Wittich, 1966; Bruger, 1981). For small fish approximately 225 mm or less in length, the Howitt streamer was shortened to approxi- mately 50 mm. 12 MVPAI MOM @@ "M 91"T LAK-Mol P@#M 'd4r.-o 4"O"toi�'D 'o@ or HOWITT INTERNAL ANCHOR TAG FLOY FD-68BC T-LOCK INTERNAL ANCHOR TAG Figure 4. The Howitt and Floy internal anchor tags. 'ILI k4wi ........... .. ... . .... Figure 5. Insertion of the disk portion of the Howitt tag was accomplished by making a small incision through the ventral musculature of the abdominal wall and inserting the disk lengthwise into the body cavity. 13 Floy FD-68BC, T-lock internal anchor tags were comprised of #20 size tubes with monofilament inserted through and secured. The dimensions of the tags were 105 mm overall with a tube length and diameter of 70 and 1.8 mm, respectively (Figure 4). A total of 4,000 Floy tags were divided into three color groups: 2,000 orange, 1,000 green and 1,000 blue. The tube portion of the Floy tag was marked on both sides; one with "REWARD FOR TAG, DATE, LOCATION, BAIT, GEAR" and the other with "MAIL TO DEPART- MENT OF NATURAL RESOURCES, 1200 GLYNN AVENUE, BRUNSWICK,, GEORGIA" and included the tag serial number. The Floy FDM-68 tagging gun with stain- less steel needle, cutter bar and ram was used to insert tags. The tagging needle was inserted to a maximum depth of 27 mm. Floy tags were inserted on the dorsal left side of the fish just below the dorsal fin (Figure 6). The T-lock portion was inserted between the interneural spines (Pterygiophores) to insure that the locking portion was firmly in place. Figures 7 and 8 show the location and position of both internal tag types attached to fish. The tagging process was begun immediately after all fish were removed from the nets and the following information was recorded: year, date, location, salinity, water temperature, barometric pressure, tidal stage, moon phase, gear type, bait, tag number, and total length of each fish. A random sample of the targeted species caught plus any injured fish were placed on ice and transported to the laboratory for ageing, reproduction and food preference studies. Surface water salinity was measured with an American Optical refractometer and surface water temperature was measured with an immersion thermometer. Fish length was measured to the nearest millimeter. Total lengths of fish possessing rounded caudal fins were measured from the tip of the head to the end of the longest median rays. Natural tip total lengths (NTL) were taken for sheepshead and spot and defined by Ricker and Merriman (1945) as the length from the tip of the head to the posterior edge of either lobe of the fork tail, whichever is longer, when lying in a natural position. The fork length was defined by Ricker and Merriman (1945) as the length which lies on a continuation of the line formed by the posterior half of the main vertebral axis from 14 - - - -----------------_--- Figure 6. Floy tags were inserted on the left side just below the post- erior portion of the dorsal fin. -0, N, 7, W IM I'M i.v M W, , Figure 7. A double-tagged red drum showing ty'pical appearance of tag streamers. 15 Figure 8. A tagged flounder showing typical appearance of How-Itt streamer. Figure 9. Tag reward poster distributed throughout coastal counties to publicize tagging studies. Ilk the tip of the head to the middle of the fork of the caudal fin. Unless stated otherwise, all lengths are total length measurements. Information recorded upon recapture included tag number, location and date of recapture, gear type, and bait used. Also, the fisherman's address and phone number were obtained in order to send a reward, letter of appreciation, and release information concerning the recaptured fish. When available, length, sex, and tag streamer conditions were recorded. Initial tag reward values of $1.00, $5.00 and $10.00 were assigned through a restricted randomized system developed by North Carolina State University's Institute of Statistics. The $1.00 rewards were increased to $2.50 after the first year in hopes of higher return rates. As of September 9, 1983, a total of $1,833.50 had been paid to fishermen for tag rewards. Publicity for the tagging study was accomplished through news releases in coastal counties, through talks to civic and sportfishing clubs, and through distribution of tag reward posters at sporting goods stores, marinas, docks and launching sites (Figure 9). Fish collected for laboratory dissection were immediately placed on ice for approximately 4 to 18 hours prior to processing. Pafford (1983) determined the shrinkage of striped mullet (250 to 290 mm) after 18 hours on ice was 1.3 percent of the total length of the live fish. Therefore, percent of shrinkage was considered insignificant. Environmental param- eters and gear data recorded during the tagging activities were also recorded for fish sacrificed for laboratory analyses. Fish captured for laboratory analyses were weighed and measured; the stomachs, otoliths, and scales were removed; and the sexes, stages of gonadal development, and fecundities were determined. All fish weighing over 100 g were weighed to the nearest gram, and specimens weighing 100 g or less were weighed to the nearest 0.1 g. In addition to natural tip total lengths, fork lengths (FL) were taken to the nearest millimeter on a random sample of 154 sheepshead (length range: 95 to 527 mm FL) and 100 spot (length range: 123 to 237 mm FL) for conversion purposes. To convert natural tip length to fork length, the conversion values of 0.94 for sheepshead and 0.95 for spot were determined to be applicable. 17 Length-weight relationships were fitted by the general parabola A =,aLb (Ricker, 1915). The coefficients "a" and "b" were determined from regressing log A on log L. Scale samples were taken from behind the left pectoral fin (Miller, 1966; Barger and Johnson, 1980). The sagittal otoliths were exposed to forcep removal by cutting and removing portions of the parasphenoid and prootic bones. The sacculus membrane was removed from each otolith. Upon removal, scale samples and otoliths from each fish were immediately placed together in labeled vials containing 70% ETOH for later processing and ageing. This prevented scale samples from drying and cracking be- fore pressing. Scale samples were taken directly from the alcohol, cleaned, and placed between labeledfcellutose plastic sheets measuring 25 x 75 x 0.60 mm (Cellutone Plasties,,,Inc., New York, N.Y.). The scales were pressed at 800C, 15,000 psi for 10 seconds in a Carver laboratory press (Fred S. Carver, Inc., Menomonee Falls, WI) as shown in Figure 10. Large scales (>20 mm dia.) were placed between 3 to 5 cellutose slides and pressed for approximately 1.5 minutes. After pressing, sample numbers were etched on the slides, and the scale impressions along with the otoliths were stored in labeled coin envelopes. Scale impressions were viewed under a binocular microscope at 40X magnification. For meticulous observations, the larger scale images were also viewed on an Eberback fish scale projector (Eberback Corporation, Ann Arbor, MI) at 48X magni- fication. A minimum of two scales were examined from each fish for recur- ring circuli pattern comparisons to aid in ring or annuli identification. In general, these recurring patterns of closely spaced or sudden breaks in the pattern of circuli were considered to be "true" annuli or year- marks (Klima and Tabb, 1959; Miller, 1966; Lux, 1971). Usually, the breaks in circuli can be identified from other incidental marks or false rings when severAl scales from the same fish are examined. Also, annuli may consist of straight circuli between radii, new circuli cut- ting over the incomplete circuli, and breaks or disconformities 18 INN M2@ @ INA 444 ij, 77M - 4@- I-Aw Figure 10. Carver laboratory press used to make scale impressions on cellutose plastic sheets. 19 in circuli forming completely around the lateral and anterior portions of the scale (Figure 11). Cutting over occurs where more recent circuli appear to cut across several other incomplete, older circuli in the lateral field. Scale increment measurements were made with an ocular micrometer in millimeter units. Increments were counted and measured diagonally from the focus to the edge of the scale (Klima and Tabb, 1959; Hofstede, 1974; Richards, 1973) (Figure 12). Otoliths were cleaned, dried, and stored with the scale impressions in open-end coin envelopes. For age determination, whole otoliths of southern and summer flounder, spot and sheepshead were immersed in a small black dish containing cedarwood oil and examined under reflected light (Lux, 1971; Williams and Bedford, 1974). Otoliths from these species were viewed under a microscope at 20X magnification. Otolith ring counts were made from the center of the core to the edge of the otoliths wit@ the concave side up (Figure 13). Otoliths of spotted seatrout, weakfish, croaker, red and black drum and southern and gulf kingfish were cross-sectioned through the core into 0.45 mm (0.018 in.) wafer sections using an Isomet low speed saw (Buehler Ltd., Evanston, IL) with a 0.012 in. thick diamond-edge wafering blade (Figures 13 and 14). Due to the difficulty in handling, small otolith sections (<3 mm dia.) were mounted on labeled acetate slides for viewing. These were viewed at 40X magnification with transmitted light. Larger oto- lith sections were placed in cedarwood oil and viewed at 20X magnifi- cation. For ease of scale and otolith ring count comparisons, the hyaline zone was counted as the end of one year's growth (Lux, 1971; Bortone and Hollingsworth, 1980). Otoliths and scales were examined twice. If the two counts did not agree, a third reading of the questionable structure was made. Disagreement after three readings precluded the use of the structure in age and growth analyses. Otoliths and scales from each fish were examined independently and compared for documentation of ageing methods. Errors most often arose by missing the first annulus or with closely spaced annuli of older fish. 20 A. Spotted seatrout B. Sheepshead 0 2@ C. Black drum D. Atlantic croaker Figure 11. Photographs A, B and C show formation of annulus by more recent circuli cutting over older circuli in the lateral portion of scales. Photograph D shows disconformities of circuli during formation of annulus. 21 ...... .. ... .. . ...... .. . . . . . . . . .... ... ...... .. .......... . . I . . . . . . . ...... . ... z' 1z &I. '0 'Nk j N Figure 12. Scale of a two year old spotted seatrout. Roman numerals indicate annuli, "F" denotes focus, and marginal increment (MI) is from the last annulus to the edge of the scale. Solid line illustrates the direction of increment measure- ment. 22 ......... .......... . A. Spot B. Southern flounder .. .................... .. .......... .. .. . .. ...... .1. . . ... . . ... 1@ Ma 10 in . . . . . . . . . Or . . . . . . . . . . . . . . . ......... .. .1111 . . . . . . . . . . . C. Spotted seatrout D. Black drum Figure 13. Whole and sectioned otoliths as viewed with reflected and transmitted light. Otoliths A, B and D were illuminated from above and viewed against a dark background. Otolith C was illuminated from below by transmitted light. 23 .......... Figure 14. Isomet low speed saw used to section otoliths. P The mean monthly growth of marginal increments on scales for each species was calculated by age to validate the time of annulus formation and the number of rings formed annually. Calculations were performed on all age groups; however, lack of sufficient monthly numbers of older age classes limited documentation of the time and number of increment formations necessary for ageing older specimens of red drum and black drum. To gain additional data to validate the number of increments formed annually, scale samples were taken from 104 red drum and 59 black drum at the time of release. Upon recapture scale samples were again taken and compared with scales taken at release. To determine whether fish length/scale radius relationships were sufficiently linear to warrant direct proportion calculations, least- squares regression analyses were performed for each species. Relatively high r2 values indicated relationships were significantly linear and that growth of the scales was isometric with growth of body length. Therefore, body lengths at time of annulus formation were back calculated with the use of the direct proportion formula L (Broadhead, 1958; S Klima and Tabb, 1959; Smith, 1969). The lengths for each age were calcu- lated as follows: L' = the length of the fish when annulus ith was formed. S' = the length of the scale radius to the ith annulus. S = the total length of the scale radius. L = the length of the fish when sampled. b Length-age relationships were fitted by the general parabola A = aL The coefficients "a" and "b" were determined by regressing log A on log L. Fish stomachs were removed and individually wrapped in cheesecloth with coded plastic identification labels and preserved in 10% buffered formalin solution. Stomachs were placed in Nalgene jars for later con- tent identification. Texas Instruments, Inc. (Dallas, Texas) was contracted to identify stomach contents of fish collected from January 1979 through May 1979. Project personnel identified stomach contents of all other fish examined. 25 00 Contents of each stomach were placed in glass bowls and examined under a binocular microscope at 1OX magnification. Food items were identified to lowest possible classification. The number of stomachs examined for each species was dependent on the total number of speci- mens captured and the number of samples necessary to statistically validate conclusions drawn from stomach analyses. To facilitate comparisons of stomach contents with food items available in the capture area, five minute trawl tows (using a three meter trawl with a 12.5 mm stretched mesh body and 6 mm knit mesh bag) and benthic samples (using a petite Ponar grab) were taken from January 1979 through June 1980 to capture available food items. In addition, 10 minute plankton net tows (using a 1-2 m diameter plankton net with 505 micron mesh) were made to capture the available food items during 1979. Texas Instruments, Inc., also identified the first five months of the plankton samples. Plankton sample identification was discon- tinued after the initial five month period. The sexes and stages of gonadal development were classified through gross examination. Sex was determined as juvenile, female, or male. Gonad developmental stages were determined using Hjort's scale of maturities as a guide (Table 6). For clarity, maturity refers to the size at which sex could be determined through gross observation while spawning refers to fish with reproductively developing gonads preceding and including spawning. Subsamples of stage V gonadal tissue were removed and the eggs counted and compared with whole gonads to determine fecundities. One gram segments were taken from the anterior, medial and posterior sections of both the left and right ovary. Egg counts from each segment were averaged to determine the mean number of eggs per gram. The fecundity was then determined by multiplying the mean by total ovary weight (Lehman, 1953; Street, 1969). All data were coded and entered into the IBM 370 computer at the University of Georgia via the remote entry terminal at Coastal Resources Division, Brunswick, Georgia. Statistical analyses were conducted by the Statistical Analysis System (SAS) package of programs (Helwig and Council, 1979). 26 Table 6. Hjort's scale of maturities for classifying the reproductively developing states of sexual organs. Reproductive Stage Stage Description I Virgin individuals. Very small sexual organs close under vertebral column. Wine-colored tor- pedo-shaped ovaries about 2-3 cm long and 2-3 cm thick. Eggs invisible to the naked eye. Whitish or greyish brown knife-shaped testes 2-3 cm long and 2-3 cm broad. Ii Maturing virgins or recovering spents. Ovaries somewhat longer than half the length of the ventral cavity about I cm diameter. Eggs small but visible to naked eye. Milt whitish, somewhat bloodshot, same size as ovaries, but still thin and knife- shaped. III Sexual organs more swollen, occupying about half the ventral cavity. IV Ovaries and testes nearly filling 2/3 ventral cavity. Eggs not transparent, milt whitish swollen. V Sexual organs filling ventral cavity. Ovaries with some large transparent eggs. Milt white, not yet running. VI Roe and milt running (spawning). VII Spents. Ovaries slack with residual eggs. Testes baggy, bloodshot. Doubtful cases are indicated by quoting two stages e.g. "St. I-II, St. VII-II, etc." NOTE: The scale was used only as a guide to general classification of maturity stages. 27 RESULTS AND DISCUSSION SPOTTED SEATROUT Spotted seatrout (Cynoscion nebuZosus) range from Laguna Madre, Mexico to south Florida in the Gulf of Mexico and along the Atlantic coast from south Florida to New York (Fischer, 1978). In Georgia, spotted seatrout are year-round estuarine inhabitants, moving in and out of the sounds with the changing seasons. In winter months they prefer the creeks and rivers where overwintering shrimp and juvenile fish are more abundant. During the cooler months, concentrations of spotted seatrout are found in areas of oyster reefs and in mouths of tidal creeks with shell and mud or sand bottoms. However, during spring and summer months they frequent sand bottom areas on beaches and near inlets. In general, spotted seatrout prefer shoreline habitat during all seasons of the year. Movement and Migration From January 16, 1979 through June 22, 1982, 3,381 spotted seatrout were tagged and released. Length frequencies of tagged seatrout in 50 mm length groups are included-in Table 7. Seatrout tagged with Howitt in- ternal anchor tags ranged in length from 175 to 655 mm and those tagged with Floy internal T-lock tags ranged 103 to 612 mm. Length frequencies of seatrout tagged with each tag type are shown in Table 8. Of 3,381 sea- trout tagged, 35 were tagged with both tag types in order to compare and evaluate tag retention qualities. Table 9 lists the length frequencies of spotted seatrout collected for tagging in 20 mm groups by gear type. Tagged spotted seatrout were returned from January 27, 1979 through July 1, 1983. Of 3,381 seatrout tagged, 456 (13.5%) were recaptured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged as high as 17.6%. Information on the number of fish released and recaptured, time at large, and distance traveled are shown in Table 7. Time at large for spotted seatrout ranged from less than one day to 1,442 28 Table 7. Number tagged, number and percent recaptured, days at large and distance traveled for spotted seatrout, Cynoscion nebuZosus, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (I<m) Length Group Tagged Recaptured Returned Avg. Max. Avg. Max. 101 - 150 1 0 0.0 151 - 200 5 0 0.0 201 - 250 45 3 6.7 231 428 8.5 25 251 - 300 123 10 8.1 134 319 9.5 59 301 - 350 986 128 13.0 236 1,250 8.2 102 351 - 400 1,448 233 16.1 201 1,442 9.7 105 401 - 450 460 56 12.2 245 1,078 9.2 110 451 - 500 192 15 7.8 253 1,080 6.3 27 501 - 550 91 5 6.2 158 279 0.2 1 551 - 600 34 6 17.6 235 578 1.1 6 601 - 650 5 0 0.0 651 - 700 1 0 0.0 Total 3,381 456 .13.5 216.9 1,442 8.9 110 l/ Distance measured in kilometers from point of release to point of recapture. Table 8. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for spotted seatrout, Cynoscion nebulosus, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numb&r Number Percent (mm) Tagged Ret2rned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 125 1 1 175 2 3 5 225 42 3 7.1 3 45 3 6.7 Uj CD 275 102 10 9.8 20 122 10 8.2 325 857 126 14.7 124 2 1.6 981 128 13.0 375 1,270 227 17.9 162 3 1.9 1,432 230 16.1 425 366 56 15.3 84 450 56 12.4 475 119 13 10.9 71 2 2.8 190 15 7.9 525 66 5 7.6 14 80 5 6.3 575 25 6 24.0 9 34 6 17.6 625 4 1 5 675 1 1 Total 2,854 446 15.6 492 7 1.4 3,346 453 13.5 NOTE: Number tagged and recaptured does not include the 35 fish tagged with both tag types. Table 9. Number of spotted seatrout, Cynoscion nebulosus, tagged 'by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length Group Gill Net (in)-!/ Trammel NO 2 2-7/8 3-1/2 4-5/8 6 Net Trawl Cast Net Trap Hook/Line Totals 110 - - - - - - 1 1 130 - - - - - - - - 150 - - - - - - 1 1 170 - - - - - - 2 - 2 190 - - - - - - I - - 1 2 210 1 3 - - - - 3 - - 3 10 230 - 3 - - - 2 5 - - 8 18 250 - 4 - - - 2 9 - - 17 32 270 3 6 - - - 6 4 - - 26 45 290 6 28 - - - 1 3 - - 25 63 310 8 130 - I - 7 2 - - 20 168 330 2 373 2 4 - 68 - - - 38 487 350 1 559 5 8 1 91 - 1 1 43 710 370 3 463 5 6 - 136 1 1 - 13 628 390 4 299 11 1 - 110 - 1 - 15 441 410 - 171 8 2 - 37 - I - 3 222 430 1 124 13 2 - 36 1 - - 1 178 450- 1 64 15 4 - 22 - 1 - - 107 470 - 46 16 2 - 26 - - - 3 93 490 - 37 8 3 - 3 - - - 1 52 510 - 26 3 5 - 8 - - - - 42 530 - 18 1 4 - 2 - - - - 25 550 - 16 - 2 - 5 - - - - 24 570 - 11 - 5 - - - - - - 16 590 - 3 - 5 - 8 610 - 1 - 3 - 4 630 - 1 - - - 1 650 - 1 - - 1 Totals 30 2,387 88 57 1 562 33 5 1 217 P81 !/Gill net sizes are stretch mesh measurements. days with an average at large time of 216.9 days. Distance traveled ranged as far as 110 km with an average of 8.9 km. Analyses of returns by tag type revealed the overall recovery rate was 15.6% for seatrout tagged with Howitt tags and only 1.4% with Floy tags (Table 8). Also, recovery rates when separated into 50 mm length groups, ranged as high as 24.0% with Howitt tags and only 2.8% with Floy tags. Of 35 seatrout tagged with both tag types, only three were re- covered. These three fish were at large from 97 to 249 days and only Howitt tags were attached when recaptured. In general, our recovery data indicate the Howitt internal disk tags are more reliable than Floy FD-68BC tags for long-term tagging studies. However, smaller fish can be tagged and multiple recaptures can be made with Floy tags. A dis- advantage of the Howitt tag is that most fish must be killed to retrieve the tag. Return rates indicate that seatrout released during the fall produced the highest survival for both tag types (Table 10). Recreational fishermen were the major source of seatrout recoveries, with 310 (68%) of the 456 returns. Only 4 (0.9%) returns were by com- mercial fishermen while study activities accounted for the remaining 142 (31.1%) recoveries (Table 11). Of the 310 recreational recaptures, 213 (69%) included sufficient information to determine lengths of creel size fish. Lengths (TL) of recreational recaptures ranged from 268 to 735 mm with an average size of 414 mm (Table 12). In general, length frequencies of recaptured seatrout indicated most creel size fish ranged from 350 to 500 mm with the greatest percentage of recoveries between 350 and 400 mm (Table 13). Sufficient information was obtained on 446 (98%) recaptured fish to determine the estuarine sector location and season of recapture. The creeks produced the highest return rate with 65.5% of all recaptures (Table 14). This percentage was proportionally higher than the percentage of trout that were released in this sector (41.7%). This higher recovery rate may indicate several possibilities: 1) seatrout may remain longer in the creeks than in the other sectors, thus a greater chance of recap- ture, 2) greater fishing pressure in the creeks, and/or 3) most seatrout 32 Table 10. Number tagged and number and percent recaptured by species, tag type and season of release. Season Winter Spring Summer Fall Combit,ed Species Tax Type Tagged Returned Percent Tagged Returned Percent Tagged Returned Percent Tagged Returned Percent Tagged Returned Percent Rovitt 1,332 198 14.9 443 62 14.0 227 29 12.8 952 157 18.4 2.854 44b 15.6 Spotted seatrout Floy 245 2 0.8 238 4 1.7 0 0 0.0 9 1 11.1 492 7 1.4 Combined 1,577 200 12.7 681 66 9.7 227 29 12.8 861 158 18.4 3,346 453 13.5 Howitt 279 5 1.8 507 4 0.8 398 8 2.1 1.170 30 2.6 2,344 47 2.0 Weakfish Floy 39 0 0.0 391 1 0.3 83 0 0.0 101 0 0.0 614 1 0.2 Combined 318 5 1.6 898 5 0.6 471 8 1.7 1,271 30 2.4 2,958 48 1.6 Howitt 64 11 17.2 7 0 0.0 L64 44 26.8 55 15 27.3 290 70 24.1 Red drum Flay 24 0 0.0 4 0 0.0 12 0 0.0 0 0 0.0 40 0 0.0 Combined 98 11 12.5 11 0 0.0 176 44 25.0 55 15 27.3 330 70 21.2 Bovitt 295 14 4.7 233 17 7.1 326 23 7.1 224 17 7.6 1,078 7L 6.6 Southern flounder Floy 20 1 5.0 60 3 5.0 5 0 0.0 18 0 0.0 103 4 3.9 Combined 315 15 4.8 293 20 6.8 331 23 6.9 242 17 7.0 1,181 75 6.4 Howitt 25 1 4.0 4 0 0.0 59 0 0.0 16 0 0.0 104 i 1.0 Summer flounder Floy 1 0 0.0 2 0 0.0 2 0 0.0 32 0 0.0 37 0 0.0 Combined 26 1 3.8 6 0 0.0 61 0 0.0 48 0 0.0 141 1 0.7 Rovitt is 4 22.2 47 10 21.3 95 38 40.0 106 Is 17.0 266 70 26.3 Black drum Ploy 16 2 12.5 14 1 7.1 3 0 0.0 17 0 0.0 50 3 6.0 Combined 34 6 17.6 61 11 18.0 98 38 38.8 123 18 14.6 316 73 23.1 sovitt 11 0 O.D 43 2 4.7 97 12 12.4 203 15 7.4 354 29 8.2 Sbeepshead Floy 22 0 0.0 39 1 2.6 0 0 0.0 0 0 0.0 61 1 1.6 Combined 33 0 0.0 82 3 3.6 97 12 12.4 203 15 7.4 415 30 7.2 Howitt 345 22 6.4 220 15 6.8 967 29 3.0 376 14 3.7 1,908 80 4.2 Atlantic croaker Floy 15 0 0.0 1,028 3 0.3 477 3 0.6 26 1 3.8 1,546 7 0.5 Combined 360 22 6.1 1,248 18 1.4 1,444 32 2.2 402 15 3.7 3,454 87 2.5 Rovitt 42 1 2.4 75 0 0.0 81 2 2.5 33 1 3.0 231 4 1.7 Spot Floy 357 6 1.7 186 3 1.6 0 0 0.0 19 0 0.0 562 9 1.6 Combined 499 7 1.4 261 3 1.1 81 2 2.5 52 1 1.9 793 13 1.6 Rovitt 77 2 2.6 77 5 6.5 47 4 8.5 106 12 11.3 307 23 7.5 Southern kingfish Floy 86 0 0.0 115 1 0.9 7 1 14.3 25 0 0.0 233 2 0.9 Combined 163 2 1.2 192 6 3.1 54 5 9.3 131 12 9.2 540 25 4.6 Howitt 1 0 0.0 0 0 0.0 0 0 0.0 1 0 0.0 2 0 0.0 Gulf kingfish Floy 2 0 0.0 5 0 0.0 0 0 0.0 1 0 0.0 8 0 0.0 Combined 3 0 0.0 5 0 0.0 0 0 0.0 2 0 0.0 10 0 0.0 NOTZ: Number tagged and returned does not include 112 fish tagged with both tag types. Table 11. Number and percent of tagged fish recaptured by recreational and commercial fishermen and project personnel. Recaptures by Fishermen Type Recreational Commercial Project Personnel Species Number Percent Number Percent Number Percent Combined- Spotted seatrout 310 68.0 4 0.9 142 31.1 456 Weakfish 17 35.4 7 14.6 24 50.0 48 Red drum 71 89.9 - - 8 10.1 79 Southern flounder 41 54.7 30 40.0 4 5.3 75 Summer flounder - - 1 100.0 - - 1 Black drum 67 72.8 2 2.2 23 25.0 92 Sheepshead 23 76.7 - - 7 23.3 30 Atlantic croaker 50 57.5 13 14.9 24 27.6 87 Spot 1 7.7 8 61.5 4 30.8 13 Southern kingfish 11 42.3 15 57.7 - - 26 Total 591 65.2 80 8.8 236 26.0 907 MW Table 12. Number and average, minimum, and maximum lengths of tagged fish recaptured by recreational fishermen. Total Length (mm) Species Number Average Minimum Maximum Spotted seatrout 213 414 268 735 Weakfish 11 326 205 392 Red drum 41 447 311 659 Southern flounder 28 340 222 436 Black drum 48 341 225 461 Sheepshead 15 300 192 393 Atlantic croaker 27 253 167 330 Southern kingfish 9 299 213 360 Table 13. Number tagged and recaptured in 50 me length groups and percent of recaptures caught by recreational fishermen. NUMBER OF FISH BY SPECIES Immath "otted asatrout veakfish Red drum Southern flounder Grow Sol"" Recapture Percent Tf Release Recapture Percent of Release Recapture Percent of j;lease Recapture Percent of (M) 1ADjtb Length Recaptures Length Length Recaptures Length Length Recaptures Length Length Recaptures IZ5 1 231 2 175 5 1053 70 225 45 750 2 18.2 243 1 3.6 275 123 4 1.9 209 1 9.1 25 494 7 25.0 M5 966 20 9.4 364 2 18.2 135 4 9.8 209 6 21.4 375 14" 77 36.1 2" 6 $4.5 65 12 29.2 as a 28.6 425 460 60 23.2 45 60 4 9.8 43 6 21.4 47S 192 34 16.0 19 7 17.0 19 S25 81 11 3.2 3 4 9.8 7 575 34 5 2.3 20 4 9.8 3 625 5 2 0.9 26 5 12.2 3 675 1 6 1 2.4 725 6 775 1 cm 975 1 1025 1 TOTAL 3381 213 100.0 2958 11 100.0 368 41 100.0 1181 28 100.0 VUKSLR OF FISH NY SPECIES Length Black drum shead Atlantic croaker Soutbers, ki-, Group Release Recapture Percent of Release ture Percent of Release Recapture Percent of Release Recapture ftrcent of (M) Length LAMStb SwArtares Lemath Length Recaptures Length Length Recaptures Lanath Length Racgtursts 75 33 125 1 15 892 39 175 37 38 1 6.7 1908 3 11.1 131 225 165 1 2.1 134 2 13.3 406 a 29.6 122 1 11.1 275 66 a 16.7 136 6 40.0 207 13 48.2 164 3 33.3 325 62 17 35.4 53 3 20.0 a 3 11.1 76 4 44.5 375 17 18 37.5 Is 3 20.0 2 425 4 3 6.2 9 475 1 2.1 7 $25 4 TOM 352 46 100.0 416 15 100.0 3456 27 100.0 540 9 100.0 OM: W0910stiom on the recapture length was not obtained for 201(342) tagged fish captured by recreational fishermen. t I Table 14. Number and percent of fish tagged and recaptured by sector. Sector Creeks Sounds Beaches ---Offshore Species Number Wumber % Number % Number % Combined Spotted seatrout Released 4409 41.7 1.866 55.2 106 3.1 0 0.0 3,381 Recaptured 292 65.5 125 28.o 29 6.5 0 0.0 446 Weakfish Released 200 6.7 2673 90.4 79 2.7 6 0.2 2.958 Recaptured 6 12.5 36 75.0 2 4.2 4 8.3 46 Red drum Released 37 10.1 311 84.5 20 5.4 0 0.0 368 Recaptured 9 12.7 59 83.1 3 4.2 0 0.0 71 Southern flounder Released 232 19.6 903 76.5 45 3.8 1 0.1 4181 Recaptured 7 10.1 31 44.9 14 20.3 17 24.7 b9 Su=aer flounder Released 15 10.6 95 67.4 1 M 30 21.3 141 Recaptured 0 0.0 0 0.0 0 0.0 1 0.0 1 Released 215 61.1 132 37.5 4 1.1 1 0.3 352 Black drum Recaptured 58 63.0 24 26.1 10 10.9 0 0.0 92 Sheepshead Released 376 90.3 36 8.7 4 1.0 0 0.0 41t) Recaptured 18 62.1 9 31.1 1 3.4 1 3.4 .19 Atlantic croaker Released 912 26.4 2,216 64.1 131 3.8 197 5.7 3,456 Recaptured 41 47.7 31 36.1 7 8.1 7 8.1 8b Spot Released 256 32.2 530 66.9 7 0.9 0 0.0 793 Recaptured 4 36.4 2 18.2 0 0.0 5 45.4 11 Southern kingfish Released 54 10.0 387 71.7 91 16.8 8 1.5 540 Recaptured 1 4.5 3 13.6 8 36.4 10 45.5 22 Gulf kingfish Released 0 0.0 4 40.0 6 60.0 0 0.0 10 Recaptured 0 0.0 0 0.0 0 0.0 0 0.0 0 NOTE: Not all recaptures had sufficient information to ascertain exact location of capture. tagged in the sounds may be migrants-moving to the beacheq for spawning or returning to the creeks. Due to weather conditions and accessibility, spotted seatrout generally receive the least amount of fishing pressure while on the beaches although they are abundant in these areas during spring and summer. They seldom occur in offshore waters and fishing pressure in these areas was virtually nonexistent. Sound and beach sectors produced 125 (28.0%) and 29 (6.5%) recoveries, respectively. Seasonally, the greatest percentage of recoveries were from the creeks during winter (41.1%) and fall (31.9%) and on the beaches during spring (34.5%) and summer (41.4%) (Table 15). Recovery rates in the sounds were over 26% from spring through fall, but dropped to 16 .8% in winter. Georgia residents fishing in state waters accounted for 284 (92%) of the 310 recreational recaptures. Of these Georgia fishermen, 245 (86%) traveled <40 km to reach their "fishing drop" or location of fish recapture while approximately 98% traveled <160 km (Table 16). The principal bait used by recreational fishermen to catch spotted seatrout was live shrimp. Approximately 64% of all recaptures caught by recreational fishermen were on live shrimp, and an additional 5% were taken on dead shrimp (Table 17). Artificial lures accounted for 27% of the returns and were primarily used during the colder months when small shrimp (<110 mm) were less abundant and water temperatures were <16 0C. Minnows, fiddlers, and cut bait accounted for the remaining 11 (3.8%) recoveries. In general, seatrout were considered by most recreational fishermen as the number one sportfish in Georgia's estuarine waters and live shrimp were the number one bait (Music and Pafford, 1982). Approximately 49% of seatrout recoveries were caught in the immed- iate area of release. Of 439 recoveries with sufficient information to ascertain movement, 397 (90.4%) were recaptured within 25 km of the tagging site; 27 (6.2%) had moved 26 to 50 km; 12 (2.7%) had traveled 51-100 km; and 3 (0.7%) had moved over 100 km from the point of release (Table 18). Seatrout exhibited little tendency for long distance move- ments as 96.6% of the recoveries were recaptured within 50 km of the 38 Table 15. Number and percent of tagged fish by season and s-tor of --aptur- Area of Recaptur, Beaches Creeks Sounds is. sea.- No. NO. NO. 2 No. 41.1 21 16.9 1 3.4 Spotted seatrout Winter 120 '7 Spring 45 4 33 26.4 10 14.5 60 17.9 S 34 "1:6 3 30.5 -r 1 27.2 12 41.4 Fall 93 37 29.6 6 20.7 Total 292 IDO.0 125 100.0 29 100.0 -6 W-kfish Winter - - 3 8.3 1 50.0 1 25.0 5 10.4 Spring 16:7 4 1 - - L 25.0 b S, l6 - 2 r 1 7 1 35 -.9 F. 11 4 66.6 28 77.: 1 5U.0 2 50.0 7t Total 6 100.0 36 100.0 2 100.0 4 100.0 @8 100.0 11.1 13 5 1 33.3 - - lu 14 Red drum Winter I a 7: Spring - - 1 8:5 3 25 Summer 2 22.2 22 -37.3 1 33.3 45.2 3.7 Fall 6 7 24 40.7 1 33.4 it Total 9 100.0 59 IDO.0 3 100.0 - 71 100@0 Southern flounder Winter - - 1 3.2 - - 1.9 i.9 Spring 1 14.3 7 22.6 7.1 2 11 11,1 S, r - - 14 45.2 ".7 2 21 30. 5 Fall 6 85.7 9 29.0 a 57.2 12 70.5 35 50.7 Total 7 100.0 31 100.0 14 100.0 17 100.0 69 1 U0. () Diack drum Winter 5 9.6 1 4.2 2 ZO.0 - - 8 8.7 Spring 9 15.5 4 67 2 20 0 is 16.3 00. Summer 21 36.2 11 4,:a 4 40:0 36 39.' Fail 23 ".7 8 33.3 2 20.0 33 35.9 Total se 100.0 24 100.0 10 100.0 92 100.0 shwavabe" Winter - - - - - - Spring 7 38 4 44.5 - 11 J7.8 Summer 6 33:', 2 22.2 - - 1 100.0 9 11.1 Fall 5 27.8 1 33.3 1 100.0 9 T.t.1 is 100.0 9 100.0 1 100.0 1 100.0 29 IOD.O AtInatk roam@ Winter 2 4.0 1 1.2 - - - 3 3.5 Spring 24 58.5 3 9.7 - - 1 14.3 28 32.5 Summer 13 31.7 is 58.1 3 42.8 2 28.6 36 41.9 Fall 2 4.9 9 29.0 4 57.2 4 57.1 19 22.1 Total 41 100.0 31 100.0 7 100.0 7 100.0 86 100.0 spot winter 1 25.0 - - - - - - 1 9.1 Spring 1 25 0 1 50 0 5 100.0 7 63.6 Sumww@ 2 50:0 - - - 2 18.2 Fail - - 1 50.0 - - 1 9.1 Total 4 100.0 2 100.0 5 100.0 11 100.0 S..tkwm kiftfi.h Winter 1 100.0 - - 2 25.0 - - 3 11.6 Sprint - - - 4 50.0 6 80.0 12 54.6 Summer 2 66.7 2 25.0 2 20.0 6 27.3 Fall - 1 33.3 - - - - 1 4.5 Total 1 100.0 1 100.0 a 100.0 10 100.0 22 100.0 XM: Of this 919 recaptnrgs, only 874 fish in,cluded sufficient information to ascertain date and location of capture. Table 16. Distance Georgia recreational fishermen traveled to reach the fishing area where tagged fish were recaptured. Distance Traveled By Georgia Recreational Fishermen Kilometers: 1-40 41-80 81-120 121-160 161-240 241-320 321-400 401-480 over 480 Species Miles: 1-25 26-50 51-75 76-100 101-150 151-200 201-250 251-300 over 300- Spotted seatrout 245 14 10 9 - 1 2 1 2 Weakfish 13 1 1 - 1 - - I - Red drum 53 2 3 3 6 - - - Southern flounder 22 2 - - 1 2 - - Black drum 49 4 - 1 1 - - - - Sheepshead - - - - 1 - Atlantic croaker 32 4 2 - - - - 2 2 Spot I - - - - - - - - Southern kingfish 7 1 2 - - - - - - Total 440 29 19 13 9 1 4 5 4 Percent 84.0 5.5 3.6 2.5 1.7 0.2 0.8 0.9 0.8 Aft Table 17. Number and percent of recreational recaptures by bait type used to catch tagged Georgia fish. Number and Percent of Recaptures by Bait Type Shr Imp Artificial cut Live FeM- Lure gait Fiddler Minnow Mussel Sand Flea SZ2rtfish NO. K;7 (z) No.-(%) iZ-(2) No. (Z) No. M NO. (Z) Total Spotted seatrout 186 (64.4) 14 (4.8) 78 (27.0) 1 (0.3) 2 (0.7) 8 (2.8) 289 weakfish 6 (42.9) 6 (42.9) 1 (7.1) 1 (7.1) 14 Red drum 62 (87.2) 7 (9.8) 1 (1.4) 1 (1.4) 71 Southern flounder 18 (72.0) 2 (8.0) 1 (4.0) 4 (16.0) 25 Black Drum 29 (36.6) 40 (50.6) 7 (8.9) 1 (1.3) 1 (1.3) 1 (1.3) 79 Sbeepabead 4 (17.4) 2 (8.7) 17 (73.9) 23 Atlantic croaker 7 (16.3) 36 (83.7) 43 Southern kingfish 5 (100.0) 5 Combined 316 (56.9) 114 (20.5) 81 (14.6) 3 (0.6) 26 (4.7) 13 (2.3) 1 (0.2) 1 (0.2) 555 VM: Recreational recaptures caught with hook and line Ilear. All recaptures did not include bait typo information. Project personnel accounted for 12 hook and line black drum recaptures. Table 18. Days at large and distance traveled for spotted seatrout, Cynoscion nebulosus, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At Distance Traveled (km) -Large 0' 0.1-1 1-5 6-25 26-50 51-100 101-200 Total Percent 1 - 50 37 1 9 29 8 - - 84 19.1 51- 100 54 2 5 15 5 1 - 82 18.7 101- 150 17 3 4 16 3 4 1 48 11.0 151- 200 11 4 3 22 3 - 1 44 10.0 201- 300 30 4 9 25 5 5 1 79 18.0 301- 500 45 2 4 12 3 2 - 68 15.5 501- 750 11 - - 8 - - - 19 4.3 750- 1,000 4 2 - 6 1.4 Over 1,000 7 - 1 1 - - - 9 2.0 Total 216 16 35 130 27 12 3 439 100.0 Percent 49.2 3.6 8.0 29.6 6.2 2.7 0.7 100.0 NOTE: Only 439 of the 456 recaptures had sufficient information to calculate distance traveled. ti 11 41 tI release site. However, 15 (3.4%) returns had traveled more than 50 km before recapture. These recaptures indicated northward movement generally during spring and summer, and southward movement during the fall (Table 19). Only three (0.6%) spotted seatrout were captured beyond Georgia waters. For the most part, movement was limited as compared to other inshore species such as black drum and southern flounder. Movement was primarily seasonal and was generally confined to a particular estuarine system. Basically, most adult seatrout.move out of the upper estuaries onto the beaches and shoal areas primarily during spring and early summer during the spawning season and return to the upper estuaries during late summer and fall (Table 20). The high return rate (49.2%) for seatrout recaptured in the immediate area of tagging indicates movement may often be within a territorial creek-river-sound-beach system. Between 64 and 75 percent of the seatrout at large from 500 to over 1,000 days were caught in the immediate area of release, indicating territorial behavior of older fish. Even though movement was significantly greater toward the beaches during the warm months and toward the creeks in the cooler months, yearly emigration and immigration of s@!atrout was approximately equal (Table 20). The greatest seasonal movement occurred during summer as indicated by a mean recovery distance of 16.2 km (Table 21). This increase in movement during summer coincided with the spawning season when most seatrout moved into areas of higher salinities. Overall, there appeared to be little relation between distance traveled and size of fish. However, recovery data indicated more move- ment or dispersal of young individuals with less movement for seatrout larger than 450 mm (Tables 7and 18). Recovery data also indicated that time at large had little effect on distance traveled as 14 recoveries at large more than two years exhibited a mean movement of only 3.6 km as compared to the overall mean movement of 8.9 km. Recovery information on distance traveled by Georgia seatrout was similar to studies conducted on the east coast of Florida and in the Gulf of Mexico. Comparison of return rates and distances traveled by tagged fish for several populations of spotted seatrout are shown in Tables 22 and 23. .0 43 Table 19. List of spotted seatrout recaptured greater than 50 km from the place of tagging. Direction Distance Season Days Release of Movestant Traveled (ka) of Capture at Large Length (mm) Location.of Capture Northward 55 Spring 54 383 Patterson Island 59 Summer 199 287 McQueen's Inlet 63 Summer 177 390 St. Catherine Beach X, 77 Summer 471 391 Wahoo River 78 Spring 160 377 Sapelo Sound 78 Spring 160 374 Sapelo Sound 81 Fall 217 389 St. Catherine Sound 82 Winter 272 397 Harris Neck River 101 Sumer 153 377 Shell-An Bluff 105 Spring 119 378 Bell's Gate 110 Summer 219 373 Wassaw Sound Southward 51 Fall 272 359 Fernandina, Florida 76 Fall 280 324 St. Mary's River 85 Fall 393 360 Fort George Inlet, Florida 102 Fall 204 329 Jacksonville, Florida 0 t I @ I ( 1 4 P I P it q 0 1 P Table 20. Seasonal movement of spotted sestrout. Cynoscion nebulosus, tagged in the coastal vaters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved By Recaptured Tagged Fish lAmgth Group Caught In Area movement Within got movement Out Of zs=ry Of Release th season (M) =rea TTO raw Worth Winter 201-250 1 251-300 7 1 - - 301-350 25 - 5 2 6 351-400 45 5 8 3 3 401-450 18 - 2 - 5 451-500 5 1 - - 501-550 - - - - 551-600 - - - - - Total 101 5 17 5 14 Percent 71.1 3.5 12.0 3.5 9.9 Spring 201-250 1 - - - - 251-300 3 - - - - 301-350 8 4 1 3 1 351-400 13 11 3 7 11 401-450 2 1 - - - 451-500 2 3 2 1 4 501-550 4 2 - - 1 Z@ 551-600 - - - - Total 33 21 6 11 17 Percent 37.5 23.9 6.8 12.5 19.3 Sumer 201-250 - - - - 251-300 1 - - 2 - 301-350 8 3 1 2 5 351-400 12 12 3 4 11 401-450 4 1 - 1 5 451-500 - - - - 501-550 2 - 551-600 - - - - I Total 27 16 4 9 24 Percent 33.7 20.0 5.0 11.3 30.0 Fall 201-250 - - - 1 - 251-300 1 - - - 1 301-350 22 7 5 6 11 351-400 23 5 7 5 16 40L-450 4 1 4 1 3 451-500 1 - I - - 501-550 2 - 551-600 2 - - - - Total 55 13 17 13 31 Percent 42.6 10.1 13.2 10.1 24.0 Combined Total 216 55 44 38 86 Percent 49.2 12.5 10.0 8.7 19.6 Table 21. Number of recaptures and average and maximum distance traveled by season of capture. Season Winter Spring Summer Fall Distance (km) Distance (km) Distance (km) Distance (km) Species NO. Avg. max. No. Avg. Max. No. Avg. max. No. Avg. max spotted seat rout 127 5.0 82 102 6.5 105 79 16.2 110 131 9.9 102 4- Weakfish 6 27.8 167 6 16.7 80 1 0.0 0.0 33 3.5 39 Red drum 11 30.8 178 7 8.3 49 23 2.4 18 38 16.8 161 Southern flounder 3 38.4 89 12 202.2 556 19 21.0 159 35 26.7 250 Su=er flounder 0 - - 1 18.5 19 0 - - 0 - - Black drum 6 159.1 619 16 14.2 213 36 23.4 217 34 44.5 463 Sheepshead 3 1.5 4.4 7 17.9 98 12 5.0 30 8 6.7 24 Atlantic croaker 1 0.0 0.0 25 15.8 179 36 9.1 113 23 8.2 37 Spot 1 2.0 2.0 8 23.1 47 2 0.0 0.0 2 58.8 118 Southern kingfish 2 304.8 537 8 18.0 41 9 21.9 128 1 0.0 0.0 Table 22. Comparison of tag recovery rates for several major fish movement investigations. Investigation Presuat study Beaumariage (1969).11 Matlock and Weaver (1979) Georgia Florida Texas Number Number Number Number Number Ru-n-ber Number Number Number Species Released Returned Returned Released Returned Returned Released Returned Returned Spotted seatrout 3,381 456 13.5 3,957 537 13.6 303 7 2.3 C@,nc,scion rwiulojuj Weakfish 2,958 48 1.6 9 3 33.3 - - - C@4noeaion mgalle Red drum 368 79 21.5 690 328 47.5 1,341 159 11.b .70i---no@j Ocellatue Southern flounder 1,181 75 6.4 - - - 199 9 4.5 Paralichth.ya lethostigna Sumner flounder 141 1 0.7 4 0 0.0 - - - Paralichth?a dentatuz Alack drum 352 92 26.1 538 1" 37.0 1,572 53 3.4 Pogoniaa cromiz Sheepshead 416 30 7.2 2,640 917 34.7 205 6 2.9 Archosargua probatacephatus Atlantic croaker 3,456 87 2.5 - - - 25 1 4.0 Micropogonias undulatus Spot 793 13 1.6 - 4 0 0.0 Leinrtcmus xanthurue Southern kingfish 540 26 4.8 7 1 14.3 - - - Menticirrhua cmericanus Gulf kingfish 10 0 0.0 133 28 21.1 1 0 0.0 Menticirrhus littoralia I/ Includes movement information on spotted seatrout tagged during the 1961-65 Schlitz and the 1963 state sponsored programs (Ingle et al.,1962; Topp, 1963; Besumartage, 1964; Reaumariage and Wittich, 1966). NOTE: A dash (-) denotes species not tagged. Table 23. Comparison of distance in kilometers and nautical miles traveled by fish for several populations of spotted seatrout, Cynoscion nebuloina. Percent of Fish Movement Maxim- Number Number Percent Kilometer 0-56 57-111 112-167 168-222 >222 Distance Traveled InvestUator Area Released Returned Returned Mile 0-30 31-30 61-90 91-120 >120 Kilometer Mile Present Study Georgia 3,381 456 13.5 96.7 3.3 - - - 110 59 Moffett (1961) West Florida 5.345 577 10.8 95.3 1.3 2.5 0.4 0.4 594 315 Beaumariage, (1969)j-1 Florida 3,957 537 13.6 99.6 0.4 - - - 83 45 Overstreet (1983) Mississippi 133 14 10.5 100.0 - - - - 26 14 Matlock and Weaver Texas 303 7 2.3 100.0 - - - - 43 23 (1979) Adkins at &2. (1979) Louisiana 2, W 30 1.1 100.021 _ - - - >4 >2 Includes movement information on spotted &"trout tagged during the 1961-65 Schlitz and the 1963 state sponsored programs. One se&trout was reported to have traveled more than 3.7 ka, but actual distance traveled was not included. HM: A dash denotes no recaptures. Length-Weight Relationship Length and weight measurements were taken for 1,369 spotted sea- trout ranging from 15 to 750 mm and 0.1 to 4,575 g. The length-weight relationship equation for a random sample of 710 seatrout was log W = 2.949 logL - 4.848. The correlation coefficient (r 2 value) for length- weight for seatrout was 0.9535 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male, female, and all spotted seatrout combined appear in Table 24. Figure 15 illustrates the length-weight relationships for spotted seatrout. Length-weight relationships calculated for Georgia seatrout showed isometric growth (b = 2.949). The greatest lengths recorded during this study for males and females were 598 and 750 mm, respectively. The heaviest male weighed 2,197 g and the heaviest female was 4,575 g. There were no significant differences between the average weights of similar size male and female seatrout for lengths less than 300 mm, but in specimens over 300 mm, females were heavier than males. Georgia sea- trout were heavier at given lengths than fish from the Gulf of Mexico. However, Chesapeake Bay seatrout were heavier than similar sized speci- mens from Georgia or the Gulf (Table 25). Age and Growth An essential component of any investigation of a population is to determine the age of fish for the estimation of growth rate, longevity, and age at maturity or spawning. Sampling fish populations can pose several difficulties for age analyses, and seldom is there a technique that will randomly sample all size groups to obtain the age composition of an entire population. Habitat and feeding preference, behavior patterns, and movements may vary with age, size and season. Also, most types of sampling gear are size selective, and gear efficiency may vary with environmental conditions. Age and growth studies based on the scale technique have been validated as an ageing method for spotted seatrout (Welsh and Breder, 1924; Pearson, 1929; Klima and Tabb, 1959; Moffett, 1961; Tabb, 1961; 49 Table 24. Length-weight equations for marine sportfish collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Sexes Combined- Females Aales Length-Weight r, Length-Weight rz Length-Weight r-r- Species Equation N Value Equatlon N Value Equation N Value Spatted seatrout logW-2.949 logL-4.848 710-1/ .95 logW-2.824 lo&L-4.516 408 .93 logW-2.683 logL-4.182 277 .86 Weakfish logW-2.920 logL-4.774 327 .95 logW-2.972 logt-4.905 258 .92 logW-2.863 logL-4.636 43 .94 I_n 0 Red drum logW-2.722 logL-4.220 103 .98 logWa2.715 logL-4.138 20 .91 logW-2.799 logL-4.431 27 .99 Southern flounder logW-3.091 logL-5.157 233 .98 logW-2.970 logL-4.844 105 .98 logW-2.984 logL-4.693 12 .95 Summer flounder logW-2.920 logL-4.807 25 .99 Black drum logW-3.075 logL-4.969 79 .99 logW-3.177 logL-5.235 18 .99 logW-2.921 logL-4.609 28 .98 Sheepshead logW-2.885 logL-4.412 118 .97 logW-2.899 logL-4.453 59 .94 logW-2.723 logL-3.977 39 .96 Atlantic croaker IoSW-3.195 logL-5.367 260 .96 logW-3.143 logL-5.235 124 .97 logW-3.159 logL-5.279 39 .97 Spot logW-3.121 logL-5.096 325 .89 logW-3.042 logL-4.901 167 .91 logW-3.007 logL-4.835 126 .87 Southern kingfish logW-3.160 logL-5.360 195 .99 logW=3.334 logL-5.780 119 .99 logW-3.221 logL-5.j23 14 .97 Gulf kingfish logW-2.872 logL-4.675 28 .81 logW-2.913 logL-4.776 26 .80 1/ Number in sample for sexes combined includes juveniles, males and females. db db 4.8-- W= .000014 L2.949 4.2-- 2 n= 710 r 95 3.6-- CD 2.4-- 0.6-- 10 @O 30 40 50 60 70 80 TOTAL LENGTH (CM) Figure 15. Length-weight relationship of spotted seatrout, Cynoscion nebuZosus,collected in Glynn County, Georgia from January 1979 through June 1982. 51 Table 25. Comparison of length-weight relationships of several populations of Spotted seatrout, Cynoscion nebulosus. Length - Weight Weight of Fish (g) Study Location Sex Equation 350 mm 500 mm 700 mm Present Study Georgia Male logW-2.683 logL-4.182 441 1,147 2,829 Female logW-2.824 logL-4.516 466 1,277 3,303 Sexes Combined- logW-2.949 logL-.4.848 452 1,293 3,487 Pearson (1928) Texas Sexes Combined - 1,248* 3,632* Moffett (1961) Florida Sexes Combined logW-3.113 logL-5.333 416 1,261 3,596 Hein et al.(1980) Louisiana Sexes Combined logW-3.154 logL-5.422 391 1,204 3,480 Brown (1981) Virginia Mal* logW-3.244 logL-5.598 448 1,424 4,240 Female logW-2.986 logL-4.924 470 1,364 3,724 Sexes Combined logW-3.043 logL-5.072 469 1,388 3,864 Sexes combined for Georgia includes juveniles, males and females. NOTE: A dash (-) denotes information not provided by investigator. An asterisk (*) denotes the weight was converted from pounds. Hein et al., 1980; Brown, 1981). Scale annuli marks were described by Klima and Tabb (1959) and Tabb (1961) as not forming by the typical crowding of the circuli as is the case with many fish scales, but are formed by definite breaks and disconformities in the circuli pattern. These breaks in circuli are generally detectable by the addition of new radii in the anterior region and the cutting over of recent circuli over older circuli in the lateral regions of the scale. Although not as widely used, otoliths have been validated as an ageing technique on fishes from temperate waters (Lux, 1971; Bagenal, 1973; Theiling, 1974; Barger and Johnson, 1980). Scale samples from 740 seatrout ranging from 56 to 750 mm were examined. Of these, 579 (78%) were considered legible for age deter- minations. Otolith sections from these 579 fish were also examined to document and compare the annuli counts ascertained from scale analyses. Annulus formation on scales and otoliths was found to be relatively simultaneous with the otolith rings being detectable slightly earlier than scale annuli for fish older than one year. The first annulus on scales was often incomplete and difficult to distinguish. Bagenal (1978) stated that in temperate latitudes annuli marks may fail to appear in age 0 fish that overwinter at small sizes. The formation of the first otolith ring was often obscured within the core structure and was seldom detectable in otoliths from Georgia seatrout. Consider- ing this scale-otolith year mark difference, scales and otoliths examined from the same fish exhibited a 98.9% agreement in annuli counts. Calculations of mean monthly growth of marginal increments vali- dated that scale annuli were formed only once annually. A single annulus formation was detectable on seatrout scales during late February and March with all scales bearing recent annuli by mid-April. The use of scales and their marks in age and growth studies depends upon the relationship between growth of the fish and its scale. Least squares regression analyses on the relationship between fish length and scale radius were performed. The correlation coefficient (r 2 value) of 0.77 (P < 0.0001) suggests the relationship was sufficiently linear to warrant direct proportion calculations to determine fish length at time 53 of annulus formation. Empirical and mean back-calculated total lengths by age for seatrout are shown in Table 26. Figure 16 illustrates the length-age relationship for seatrout, and the principle of least squares was employed to draw the line of best fit. Equations for the length- age relationships for male, female, and all seatrout combined are shown in Table 27. Table 28 shows the empirical and weighted mean back-calcu- lated lengths for juvenile, male, female and all spotted seatrout com- bined. To document the annual growth rate determined from back-calculations, mean growth rates for tagged seatrout at large for approximately one, two, and three year intervals were calculated. The average release length and approximate age for 31 seatrout at large from 11 to 13 months was 358 mm and age III, respectively. The mean annual growth for seatrout of that approximate age may range from 56 to 79 mm (Table 28). The estimated mean annual growth for the 31 recaptured seatrout was 68 mm, substanti- ating the estimated annual growth for that size fish based on back-calcu- lation data. Also, seatrout approximately three years old when tagged and at large for two and three year intervals exhibited mean growth rates of 137 and 161 mm, respectively. These observed growth increases are fairly consistent with values derived by combining the annual growth estimates for the 3rd and 4th year's growth increase (135 mm) and the 3rd, 4th, and 5th year's growth (181 mm). One female seatrout measuring 378 mm when released and at large for 1,442 days exhibited a growth of 294 mm. However, this growth increase was slightly greater than the back-calculated estimated growth for that size female at large four years. The oldest seatrout collected in Georgia were age VIII for females and age VI for males. These findings are similar to those for fish studied in Texas and Florida (Table 29). However, ageing studies indi- cate that trout in Virginia live substantially longer than those in more southerly waters. Maximum age of seatrout from the Chesapeake Bay area was determined to be XV (Brown, 1981). A substantial overlap in sizes of seatrout in Georgia occurred between ages 11 and VI. Brown (1981) observed similar findings for 54 Table 26. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebuLosus, collected in the coastal waters of Glynn County, Georgia from JanuAry 1979 through June 1982. -Mean Back Length Range Mean Length Calculated lengths of Successive Scale Rings -Age Number at Capture at Capture 1 2 3 4 5 6 7 8 0 31 56 - 258 152 1 10 245 - 373 302 226 Ln 2 202 216 - 435 319 173 270 3 202 264 - 615 381 186 293 358 4 64 320 - 609 467 195 311 388 444 5 34 430 - 631 524 193 310 384 449 493 6 29 430 - 608 526 180 285 350 408 463 504 7 5 535 658 612 183 296 372 433 505 563 598 8 2 585 750 668 195 301 355 430 519 581 638 665 Weighted Means 184 287 366 436 482 516 609 665 Growth Increments 184 103 79 56 46 34 93 56 NOTE: Lengthg measured in millimeters. 70 A= .000173 L1.658 2 n= 711 r 58 60 0 50 CD _j 40 0 30 20 10 1 2 3 4 5 6 7 8 AGE (YEAR) Figure 16. Length-age relationship of spotted seatrout, Cynoscion nebulosus, collected in Glynn County, Georgia. 56 qP qF W Table 27. Length-age equations for marine sportfish collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Sexes combined Females Males Length-Age rz Length-Age rz Length-Age r2 Species Equation I,- Value Equation N Value Equation N Value Spotted seatrout lo&A-1.658 logL-3.761 711 .58 logA=1.700 logL-3.894 407 .63 logA=1.880 logL-4.237 277 .46 Weakfish lo&A-1.625 lo&L-3.606 328 .67 logA-1.657 logL-3.692 259 .60 logA-1.618 logL-3.543 43 .86 Red drum-2/ logA-1.691 logL-4.415 104 .52 logA-1.546 logL-4.044 20 .44 logA-1.952.logL-5.159 27 .76 Southern flounder lo&A-1.191 logL-2.646 233 .63 logA=1.277 logL-2.887 105 .72 logA=1.029 logL-2.140 12 .69 Black drum-2/ logA-1.771 logL-4.158 81 .87 logA-1.754 logL-4.111 18 .95 logA=1.419 logL-3.242 30 .56 Sheepshead logA-1.953 logL-4.366 118 .86 logA=1.905 logL-4.244 59 .89 lo&A=1.854 logL-4.102 39 .81 Atlantic croaker lo&A=1.953 logL--4.326 260 .14 logA-1.963 logL-4.354 124 .20 logA=2.071 logL-4.570 39 .01 Spot lo&A=1.877 logL-3.965 326 .31 lo&A=1.695 logL-3.539 167 .29 lo&A=2.080 logL-4.432 127 .25 Southern kingfish lo&A=1.533 logL-3.366 196 .47 logA-1.586 logL-3.511 120 .56 logA-1.737 logL-3.783 14 .84 Gulf kingfish logA-0.889 logL-1.811 28 .51 logA-0.889 logL-1.855 26 .52 I/ Number in sample for sexes combined includes juveniles, males, and females. I/ Equation based on individuals less than four years of age. NOTE: Number of summer flounder not sufficient to warrant length-age equation. Table 28. Number, empirical and back-calculated total lengths, and growth increments by sex and age for spotted seatrout, *noacion nebuZoaua, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Sex 1 2 3 4Me 5 6 7 Juveniles Number 0 1 Mean Length at Capture- - 232 Back-Calculated Length 121 196 Growth Increment 121 75 Males Number 3 102 83 13 4 9 @,n Mean Length at Capture 275 306 342 390 493 470 CO Back-Calculated Length 175 268 328 379 424 449 Growth Increment 175 93 60 50 46 25 Females Number 7 99 119 51 30 20 5 2 Mean Length at Capture 314 332 408 487 528 552 612 667 Back-Calculated Length 190 300 384 451 496 539 609 665 Growth Increment 190 110 84 67 45 43 70 56 Combined Number 10 202 202 64 34 29 5 2 Mean Length at Capture 302 319 381 467 524 526 612 668 Back-Calculated Length 184 287 366 436 482 516 609 665 Growth Increment 184 103 79 56 46 34 93 56 NOTE: Lengths measured in millimeters. @, I " I k F I F I F IF IF W Table 29. Comparison of mean back-calculated total lengths at age for several populations of spotted seatrout, ne"U10SLtz. Back-Calculated Length at Age Study Location Sex 1 11 111 IV V vi V11 Vill IX X XI x1i Male 175-!/ , 68 328 378 424 449 Present Study Georgia Female 190 300 384 451 496 539 609 665 Combined 184 267 366 43b 482 516 bO9 bb5 Welsh and Breder* West Florida Combined 140 281 378 439 488 525 (1924) Pearson (1929)* Texas Combined 183 293 366 427 488 537 598 634 Male 140 229 305 371 416 450 Klima and Tabb* Northwest Female 143 233 315 384 454 516 533 (1959) Florida Combined 142 232 311 381 450 515 533 Male 156 251 316 378 432 533 Fort Myers Female 160 255 325 393 453 499 526 534 Florida Combined 159 254 322 390 449 525 Moffett (1961)* Kale 157 251 321 394 464 529 Cedar Key Female 159 259 328 394 467 Florida Combined 159 257 327 394 466 Tabb (1961)* East Florida Combined 201 303 387 468 558 650 684 761 Male 153 244 313 378 432 440 501 554 Brown (1981) Virginia Female 191 279 347 404 449 493 523 560 588 644 Combined 170 260 353 414 441 475 521 561 603 648 687 721 Converted from standard lengths to total lengths using the formula TL= 1.22 SL 1/ Lengths measured in millimeters. trout in the Chesapeake Bay area. However, the magnitude of overlap in lengtb-age shown in Table 26 can be partially explained when the lengths are examined by sex (Tables 30 and 31). In general, female seatrout in Georgia were significantly larger than males of equal age. Similar size-age differences between sexes were also documented for seatrout in Florida and Virginia (Klima and Tabb, 1959; Brown, 1981). Growth rates of Georgia seatrout were not significantly different from those reported from other areas (Table 29). Growth in Georgia was rapid during the first three years of life with daily growth incre- ments of 0.50, 0.28, and 0.22 mm, respectively (Table 32). Daily growth rates slowed after age III or IV. Also, annual growth increments varied widely in older fish, but this may be attributed to sexual growth dif- ferences and the low number of large fish collected (Table 28). To show how such variations of growth rates may occur within a population or between different populations, ages of seatrout collected in Glynn County during 1979 were compared to fish collected during 1982 (Tables 33 and 34). Weighted mean back-calculated lengths ranged from 2 to 43 mm larger for the 1982 seatrout with an average yearly increase of 24 mm over the 1979 fish for the first five years of life. This variation in length-age of Georgia seatrout may be the result of two severe winters during 1977 and 1978. These severe winters designated by the Federal Government as "shrimp disasters" not only killed crusta- ceans but also killed fish and other estuarine dependent organisms as well (Music, 1979). Such natural estuarine disasters could temporarily eliminate or significantly limit many food species of the spotted sea- trout. It is assumed the general lack of abundant food for good nutrition as well as the increased energy spent seeking scarce prey would result in less fish growth. Maturity and Spawning Georgia's spotted seatrout are year-round residents in coastal waters and for the most part are estuarine specific to a particular sound system. They are spawned in and utilize their particular estuarine 60 Table 30. Mean back-calculated total lengths for male spotted seatrout, cynoscion nebulosus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back Calculated Ring Length Range Mean Length Lengths of Successive Scale Rings Class Number at Capture at Capture 1 2 3 4 5 6- 0 4 159 - 204 183 1 3 245 - 301 275 229 2 101 216 - 377 306 167 261 3 83 285 - 403 83 181 273 326 4 13 320 - 454 390 179 285 340 379 5 4 430 - 598 493 162 267 341 392 447 6 9 430 - 532 470 170 269 322 367 411 449 Weighted Means 175 268 328 378 424 449 Growth Increments 175 93 60 50 46 25 NOTE: Lengths measured in millimeters. Table 31. Mean back-calculated total lengths for female spotted seatrout, Cynoscion nebuzosus collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back Length Range Mean Length Calculated Lenaths of Successive Scale Rings Age Number at Capture at Capture 1 2 3 4 5 6 7 8 0 3 157 - 258 204 1 7 265 - 373 314 225 2 99 223 - 435 332 181 281 3 119 264 - 615 408 190 307 380 4 51 379 - 609 487 199 317 401 460 5 30 465 - 631 528 198 315 390 457 499 6 20 494 - 608 552 185 292 362 426 486 528 7 5 535 - 658 612 183 296 372 433 505 563 598 8 2 585 - 750 668 195 301 355 430 519 581 638 665 Weighted Means 190 300 384 451 496 539 609 665 Growth Increments 190 110 84 67 45 43 70 56 NOTE: Lengths measured in millimeters. I ri (I (I a a a a a Table 32. Estimated mean daily growth of marine sportfish by sex for each year of life. Mean Daily Growth for Year of Life (mm) Species Sex 1 2 3 4 5 6 Male O@48 0.25 0.16 0.14 0.13 0.07 Spotted seatrout Female 0.52 0.30 0.23 0.18 0.12 0.12 Combined 0.50 0.28 0.22 0.15 0.13 0.09 OF Male 0.41 0.27 0.16 0.11 - - Weakfish Female 0.46 0.27 0.18 0.15 0.16 0.15 Combined 0.44 0.28 0.18 0.14 0.18 0.15 Male 1.19 0.61 0.25 - - - Red drum Female 1.13 0.64 - Combined 1.10 0.69 0.26 - Male 0.33 0.34 0.27 - - - Southern flounder Female 0.47 0.44 0.35 0.34 0.06 0.21 Combined 0.43 0.44 0.34 0.34 0.06 0.21 Summer flounder Combined 0.39 - - - - - Male 0.52 0.40 0.25 0.18 - - Black drum Female 0.53 0.41 0.32 0.25 0.21 0.10 Combined 0.54 0.38 0.29 0.27 0.24 0.10 Male 0.40 0.29 0.24 0.13 0.10 0.09 Sheepshead Female 0.40 0.30 0.21 0.17 0.14 0.09 Combined 0.41 0.28 0.22 0.15 0.13 0.09 Male 0.44 0.18 - - - - Atlantic croaker Female 0.45 0.20 0.15 0.15 0.04 Combined 0.45 0.19 0.16 0.15 0.04 Male 0.37 0.19 0.03 - - - Spot Female 0.33 0.21 0.06 - - - Combined 0.35 0.20 0.05 - - - Male 0.41 0.23 0.11 - - - Southern kingfish Female 0.43 0.34 0.13 0.09 - - Combined 0.42 0.34 0.12 0.11 - - Male 0.27 - - - - - Gulf kingfish Female 0.33 0.40 - Combined 0.33 0.40 - NOTE: Dash (-) denotes fish were not collected in age group. Sex combined includes juveniles, sales, and females. 63 Table 33. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebuZns@ -4,s, through age V for fish collt-eted in the coastal waters of Cl%,nn Countv, Georgi;i (hiring 1979. Mean Back Calculated Length Range Mean Length LenZths of Successive Scale_@i Age Number at Capture at Capture 1 2 3 4 5 0 2 138 - 148 143 1 2 293 - 323 308 225 2 120 223 - 422 335 183 281 3 138 264 - 521 372 190 294 357 4 21 339 - 544 423 176 296 363 412 5 10 440 - 518 488 196 310 383 434 475 Weighted Means 186 289 359 419 475 Growth Increments 186 103 70 60 56 NOTE: Len-ths measured in millimeters. Table 34. Mean back-calculated total lengths for spotted seatrout, Cynoscion nebulosus., through age V for fish collected in the coastal waters of Glynn County, Georgia during 1982. Mean Back-Calculated Length Range Mean Length Lengths of Successive Scale Rings__ Age Number at Capture at Capture 1 2 3 4 5 0 27 56 - 258 155 1 8 245 - 373 301 227 2 39 252 - 435 316 169 271 3 43 272 - 615 412 182 296 370 4 26 320 - 609 491 206 321 400 458 5 14 430 - 631 554 201 314 396 466 518 Weighted Means 188 295 384 461 518 Growth Increments 188 107 89 77 57 NOTE: Lengths measured in millimeters. systems as nursery grounds for all stages of development and growth. A description of the classification of maturity stages of gonadal de- velopment in fishes is presented in Table 6. During this study, the smallest spotted seatrout for which the sex was determined through gross examination was 157 mm for females and 159 mm for males. The smallest female to exhibit maturing or prespawn- ing ovaries (stage III or greater) was a 229 mm (age II) specimen in its third year of life. The smallest male stage IIIor greater was 342 mm, but collection of the smaller reproductive males may have been biased by gear selectivity as males are reported to mature earlier than females (Guest and Gunter, 1958). Seatrout are generally believed to mature at one to three years of age. Pearson (1929) found that Texas seatrout matured at the end of their second year but did not spawn until the third. Miles (1950) re- ported that 10% reached maturity at the end of their first year (16 cm length), 50% at the end of the second year (25 cm length) and that sexual maturity was obtained by the end of the third year. Moody (1950) found that females did riot spawn until they reached 240 to 250 mm length in Cedar Key, Florida. Table 35 presents the stages of gonadal development for female and male spotted seatrout by month. Females exhibiting maturity stages I through III were collected every month, but spawning activity began in April when 10.2% of the females exhibited advanced ovarian development (stages IV through VII or spent). Spawning activity peaked in May when 43.4% of the females showed advanced development, but in June there was a sharp drop to only 17.0%. In July, the occurrence of advanced stages increased somewhat to 34.2% to create a second smaller spawning peak before again declining in August to 26.9%. By September, most spawning activity was complete as only 6.8% of the females showed advanced de- velopment. From October through March advanced ovarian development was rare, but two stage V females (3.0%) were collected in November, and one stage TV female was found in January (1.0%). During the study period, salinities ranged as high as 36 parts per thousand in inland waters, and water temperatures ranged from 70 to 330C 66. Table 35. Number of spotted seatrout, Cynoscion nebuZosus, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage 1I III IV V VI VII Month F M F M F R F M F M F January 64 82 29 7 6 0 1 1 February 93 70 17 0 2 0 March 95 53 14 0 1 0 April 49 50 21 13 9 1 7 0 1 0 1 0 May 2 20 32 21 30 5 6 2 30 0 13 0 June 4 19 36 10 9 0 4 0 4 0 1 0 1 0 July 6 13 15 3 4 3 4 0 8 0 1 0 August 5 11 12 0 2 0 3 0 4 0 September 26 13 12 4 3 0 2 0 1 0 October 46 13 4 0 November 54 16 9 0 1 0 2 0 December 61 25 4 0 1 0 throughout the year with an average monthly temperature of 21 0C. Bi- monthly water temperatures and salinities are shown in Tables36and 37. As spawning activity commenced in April, females exhibiting advanced ovarian development were found only in salinities above 26 0/oo (Table 38). In May, the peak month for spawning activity, advanced ovarian develop- ment was observed in salinities ranging from 11 to 36 0/oo. Nearly half (43.4%) of the May females exhibited advanced ovarian development. Further- more, there was a definite increase in the occurrence of advanced stages with each five part increase in salinity levels. These increases were as follows: 11-15 0/oo (23.1%), 16-20 0/00 (29.6%), 21-25 '/oo (34.8%), 26-30 0/oo (56.1%), 31-35 0/oo (75.0%) and 36-40 0/00 (100.0%). Unfortunately, all females collected in June were collected from salinities between 26 and 30 0/oo. Although most of the specimens col- lected during July and August were collected from salinities greater than 21 0/oo, one July female exhibiting advanced development was taken from salinity less than 15 0/oo. By September, advanced maturity stages were uncommon in all salinity levels, and by October no advanced stages were observed (Table 38). Table 39 presents the maturity stages for female and male seatrout by water temperature and salinity gradient. Only one female exhibiting advanced ovarian development (stages IV through VII) was collected from 0 0 water temperatures below 15 C. At water temperatures 16-20 C advanced maturity began to appear when three females (1.9%) exhibited advance- ment. However, once water temperatures excqeded 21 0C the percentage of females exhibiting advanced ovarian development jumped sharply to 22.6% (Table 39). Similar findings were reported in Texas by Simmons (1957) and in Louisiana by Fontenot and Rogillio (1970). Hein and Shepard (1979) related peak spawning to photoperiod in Louisiana. Arnold et al. (1976) found that trout spawn in the laboratory over a salinity range of 0 26-30 /oo at 260C and 15 hours light. Taniguchi (1980) found that optimum temperature and salinity in laboratory experiments were 28.0 0C and 28.1 0/oo, respectively. When viewed according to salinity level or gradient, the occurrence of advanced stages generally increased with the increase in salinity 68 W Table 36. Average surface water temperatures 0C) by sector and month in bi-monthly increments for Glynn County, Georgia from January 1979 through June 1982. AVE%%C.E SURVACE WATER TFMP. ('C) CREEKS SOUNDS BEACHES AREAS COMBINED Days Days Monthly Days Davs Monthiv Davs Days Monthly Days Days Monthl-v MONTH 1-15 16-31 Average 1-15 16-31 Average 1-15 16-31 Average 1-15 16-31 Average January 11.6 II.B 41.7 11.0 1U.6 10.8 12.0 8.0 10.0 11.4 11.2 11.3 February 10.3 13.3 11.8 14.1 12.8 13.5 10.0 15.0 12.5 11.6 13.2 12.4 March 14.9 18.6 Ib.7 13.7 17.2 15.6 16.0 16.1 16.1 14.6 17.8 16.2 April 20.7 22.8 21.8 19.5 22.4 21.0 19.5 24.0 21.8 20.0 22.7 21.4 May 23.7 26.2 25.0 23.3 25.7 24.5 24.5 25.6 25.1 23.6 25.9 24.8 June 27.2 28.5 27.9 28.5 29.0 28.8 30.0 28.0 29.0 27.6 28.8 28.2 July 29.3 29.8 29.6 29.2 29.8 29.5 30.0 30.3 30.2 29.2 29.8 29.5 August 30.6 29.7 30.2 30. 7 2 @k. 11) 29.8 30.0 29.5 29.8 30.7 29.1 29.9 September 29.0 27.1 28.1 28.4 27.0 27.7 28.7 27.7 28.2 28.6 27.4 28.0 October 24.4 22.1 23.3 25.2 22.9 24.1 25.7 23.3 24.5 24.8 22.7 23.8 November 20.0 16.4 18.2 20.1 16.7 18.4 21.0 19.5 20.3 20.1 16.7 18.4 December 15.0 11.9 13.5 14.8 11.3 13.1 15.0 10.0 12.5 14.9 12.3 13.6 Table 37. Average surface water salinities (0/oo) by sector and month in bi-monthly increments for the coastal waters of Glvnn County, Georgia from January 1979 through June 1982. AVEFUGE SURFACE WATER SALINITY (0/oo) CREEKS SOUNDS BEACHES AREAS COMBINED Day Day Combined Day Day Combined Day Day Combined Day Day Combined MONTH 1-15 16-31 Average 1-15 16-31 Average 1-15 16-31 Average 1-15 16-31 Average January 23.8 22.5 23.2 27.2 21.8 24.5 28.0 27.0 27.5 25.3 22.2 23.7 February 21.6 19.6 20.6 22.1 21.9 22.0 24.3 25.1 24.7 22.7 22.2 22.4 March 18.3 18.3 18.3 19.6 18.8 19.2 28.0 24.6 26.3 19.7 18.9 19.3 April 19.4 17.7 18.6 21.1 20.2 20.6 25.0 28.5 26.7 -20. 5 18.6 19.5 May 22.5 22.2 22.4 23.6 24.1 23.8 28.2 26.8 27.5 24.2 23.5 23.8 June 23.5 26.1 24.8 28.5 30.4 29.4 34.7 27.6 31.2 -28.9 28.7 28.8 July 26.3 29.2 27.8 29.3 27.8 28.6 30.0 31.9 31.0 28.5 29.6 29.1 August 28.1 26.9 27.5 30.2 30.0 30.1 29.5 31.4 30.4 29.1 29.2 29.1 September 24.5 26.8 25.7 26.8 25.3 26.0 31.0 33.5 32.3 27.4 28.5 28.0 October 27.1 25.0 26.1 28.9 25.4 27.1 30.6 31.5 31.1 28.9 27.3 28.1 November 24.5 23.9 24.2 26.0 28.1 27.0 27.0 27.3 27.2 25.5 26.4 26.1 December 23.6 25.2 24.4 27.8 28.2 28.0 28.5 31.0 29.8 26.6 28.1 27.4 t I ti @' I @ I k I I P I P w w Table 38. Stages of gonadal development for spotted sestrout, Cynoacian nebulosus, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1992. Surface Water Salinity (9100, Reproductive 0-5 640 26-30 31-35 36-40 Totals - jk.Ls - - - tkilth Stage -F-It F N N F N F N F N January 2 16 50 28 12 37 0 1 - - 64 82 3 2 10 1 11 4 5 0 - - 29 7 2 0 4 0 6 0 IV V-Vll IP*bvuary 1 2 1 12 9 6 a 36 20 8 7 29 25 93 70 4 0 1 0 4 0 5 0 3 0 17 0 2 0 2 0 IV-Vil me I A 1 10 5 26 17 46 28 9 2 95 53 11 1 0 2 0 5 0 6 0 - - 14 0 111 0 L 0 IV-VII - w April I S 6 6 S b 5 12 7 21 13 1 7 1 7 - - 52 47 11 8 2 2 2 3 2 A 2 1 3 3 2 - - 21 13 @j 111 4 0 1 0 3 1 1 0 9 1 IV V 4 0 3 0 7 0 VI 1 0 1 0 1 0 1 0 Nay 0 3 2 9 0 2 0 6 - - 2 20 5 1 10 3 7 7 10 10 - - - - 12 21 5 2 7 0 a 0 a 2 2 1 - - 3D 3 IV - - 2 1 1 0 1 1 2 0 - - 6 2 V 2 0 4 0 4 0 15 0 4 0 1 0 30 0 Vi 1 0 2 0 3 0 7 0 - - - - 13 0 VII jams 2 8 2 3 0 8 - - 4 19 is 5 9 1 9 4 - - 36 10 2 0 2 0 5 0 9 0 IV 1 0 1 0 2 0 4 0 V 2 0 1 0 1 0 4 0 VI - - 1 0 1 0 1 0 1 0 July 1 0 4 6 1 3 0 4 6 13 - - 10 0 3 1 2 2 15 3 1 0 2 2 0 1 4 3 IV 1 0 1 0 1 0 - 3 0 V 1 0 3 0 4 0 a 0 VI Vii 1 0 1 0 Table 38. (continued) Surface Water Salinity (0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 - 31-35 36-40 Totals Kunth Staste F M -i-M -F M F M F M F M F M F M F August - 2 5 1 1 2 5 5 11 2 0 5 0 3 0 2 0 12 0 1 0 1 0 2 0 IV 2 0 - - 1 0 3 0 V 1 0 3 0 4 0 VI-VII - - - - September 1 3 1 2 1 3 0 5 4 10 6 3 1 26 13 11 2 0 0 1 5 1 5 2 12 4 111 1 0 2 0 3 0 IV - - 0 1 0 2 0 V 1 0 1 0 VI-VII October 1 10 2 21 9 13 1 1 0 46 13 11 0 1 0 1 0 1 0 4 0 November 1 33 4 21 12 54 16 11 5 0 4 0 9 0 111 0 1 0 IV - V 2 0 2 0 VI-VII - - December 1 9 1 46 22 5 2 1 0 61 25 11 4 0 4 0 111 1 0 1 0 IV-VII - - Combined 1 5 1 28 20 24 22 101 72 238 136 104 105 8 26 508 382 Totals 11 1 0 14 2 10 4 28 7 80 16 50 21 22 8 205 58 III - - 5 0 5 2 11 0 19 1 20 4 8 2 68 9 IV - - - - 1 0 4 2 6 0 3 1 5 0 19 3 V - - 1 0 2 0 5 0 10 0 29 0 8 0 1 0 56 0 VI - - - - 1 0 2 0 3 0 10 0 - - - - 15 0 VII - - - - - - - - 1 0 - - 2 0 - - 3 0 OF Table 39. Stages of gonadal development for spotted seatrout, C@noecion nebulosus, by water temperature and salinity gradients for fish collected in Glynn County. Georgia from January 1979 through June 1982. Surface Water Temperature (OC) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Total@ (0100) Stage F 17-it -F R F M -F-M F M P M 2 1 3 0 5 1 0-5 1 0 - - - - 1 0 III-Vil - - - - - - 1 12 9 9 4 4 6 3 1 - - 28 20 it 4 0 7 2 1 0 2 0 - - 14 2 111 4 0 1 0 5 0 6-10 IV - - V 1 0 1 0 VI Vi 1 6 8 2 2 14 9 0 2 1 1 - - 23 22 1 0 1 0 2 2 6 1 0 1 - - to 4 5 1 0 1 5 2 IV - - 1 0 1 0 V 2 0 2 0 VI 1 0 1 0 Vil - - - - 1 40 29 23 13 8 17 29 13 1 0 - - 101 72 it 6 2 2 0 2 2 16 3 - - 2 0 28 7 111 3 0 1 0 7 0 11 0 16-20 IV I 1 3 1 4 2 V 4 0 1 0 5 0 Vi 2 0 - - 2 0 sk VII - - - - - - or 1 42 21 74 43 69 26 36 16 24 1 0 238 136 it 7 1 11 0 12 0 10 8 40 7 - - 80 16 III - - 1 0 - - 5 1 13 0 - - 19 1 21-25 TV - - - - - - - - 6 0 - - 6 0 V - - - - - - 2 0 8 0 - - 10 0 VI - - - - - - 3 0 - - - - 3 0 VII - - - - - - - - 1 0 - - 1 0 1 20 45 35 20 21 13 14 8 14 18 0 1 104 105 11 4 3 0 4 0 6 8 24 9 2 0 50 21 6 0 - - 1 0 6 1 6 3 1 0 20 4 26-30 IV - - - - - - 0 1 3 0 - - 3 1 V - 3 0 9 0 15 0 2 0 29 0 VI - 7 0 1 0 - 8 0 Vil - - - 1 7 5 15 1 3 8 26 11 5 0 0 3 2 11 6 2 0 22 8 111 3 1 5 1 8 2 31-35 IV 2 0 3 0 5 0 V 7 0 1 0 8 0 Vi - - - - VII 1 0 1 0 2 0 I-IV - - - - 36-40 V - - 1 0 1 0 VI - - - - Vil - - - - I - - 123 114 134 78 124 69 84 58 40 59 2 4 507 382 11 1 0 34 7 17 0 28 6 42 22 78 23 6 0 206 58 III - - 9 0 1 0 6 0 26 4 25 5 1 0 68 9 TOTALS IV - - I I - - - - 5 2 13 0 - - 19 3 V - - - - - - 3 0 24 0 27 0 2 0 56 0 VI - - - - - - - - 14 0 1 0 - - 14 0 Vil - - - - - - - - 1 0 2 0 - 3 0 73 (Table 39). No advanced stages were observed at salinity levels <5 O/oo. Only 6% of all females collected from salinities <25 0/oo exhibited ad- vanced ovarian development with no more than 10% occurrenc e in any lower salinity gradient. However, at salinities of 26-30 0/oo the occurrence of advanced ovarian development jumped sharply to 18.7%, and at salinities above 31 0/oo the percentage jumped to 29.6%. From the figures presented above it is evident that peak spawning takes place at temperatures above 210C and salinities above 26 0/00. It is logical to conclude, therefore, that maximum spawning activity in Georgia takes place in the higher salinity waters of the lower sounds and along the beaches where salinities exceed 25 0/oo once the water temperature exceeds 210C. These conclusions are supported by similar findings reported previously in Georgia by Mahood (1975). In addition, large catches of "roe" trout by recreational fishermen during May and June in the sounds and along the beaches further substantiate these findings. Since Georgia's sounds are relatively small, spawning activity in these areas would be in close proximity to the beaches and the higher salinity waters. Table 40 presents a description of spawning activity, through the occurrence of advanced ovarian development, for female seatrout according to lunar phases. When viewed according to lunar phase, little variation in spawning activity was found. When advanced stages of female seatrout were grouped by moon phase the percentages were: new moon, 22.1%; first quarter, 14,7%; full moon, 28.4%; last quarter, 21.1%; and split phases, 13.7%. Apparently there was more spawning activity during full moon and new moon periods even though advanced stages were encountered throughout the lunar cycle. This may have some significance as full and new moon phases are periods of high tidal amplitude and maximum turbidity which may benefit survival rates. Adkins et al, 1979 (Cited in: Adkins and Bourgeois, 1982) reported that a sharp increase of gravid females oc- curred shortly before each full moon and that spent females were found shortly after the full moon in Louisiana. Our data also show some variation according to lunar phase, but the difference is not strongly pronounced. 74 IRV 14 F Table 40. Number and percent of fish showing advanced gonadal development during various mo@ Phases by species and sex for fish collected in Glynn County, Georgia fr@ issaaary 117, through June M2. Muce PUASE species 3 pays lww 3 Days 3 Days LASIt 3 Days 3 Days Full 3 Day. 3 Days Lear 3 Days Split CoubloW bweductLom Prior NDOIR After Prior After Prior Moon After Prior After phd". It R T-K F f__ T-M - - _MwI&_ stelesi 7 w K T M M F X F M F x Sported 110. examined 1 127 53 48 26 34 a 76 42 22 17 33 19 67 57 21 7 t2t 59 98 42 5 b 139 70 55 47 87b 452 O"t-It Ma. ;;@' 10 1 - - 3 0 5 1 6 0 3 0 10 0 1 0 to 0 10 0 - - to 1 13 0 95 3 Percent 14.2 1.9 - - 8.8 0.0 6.6 2.4 27.3 0.0 9.1 0.0 14.9 0.0 4.8 0.0 13.2 0.0 10.2 0.0 - - 7.2 1.4 15.3 0.0 IO.b 0.7 Weakfish ft. examined 37 10 0 1 3 1 25 12 7 5 29 1 5 1 19 1 43 2 45 4 1 0 29 5 11 0 257 43 No. adwasced 6 0 - - - - 1 0 - - - - 4 0 - - I 1 6 0 - - - - z 0 20 1 Percent 16.2 0.0 - - - - 4.0 0.0 - - - - 50.0 0.0 - - 2.3 50.0 13.3 0.0 - - - - 18.2 U.o 7.8 Red drum No. examJned 1 1 4 1 - - 0 6 - - 3 1 3 4 0 1 4 5 1 2 2 0 U 2 2 3 20 26 No. advanced - - - - - - - - - 0 1 0 1 Percent - - - - - - - - - 0.0 33.3 0.0 3.7 Sonthern go. ezusimed 24 2 2 0 3 2 12 5 3 1 10 0 5 0 2 0 7 0 4 0 2 0 lb L 13 0 103 11 flounder go. advanced - - - - - - - - - - - - Percent - - - - - - - - - - - - Black drum NO. examin" 3 2 - - 0 1 1 1 - - 2 9 2 1 4 0 2 7 5 3 19 24 NO. **Vaacod 2 a - - - - - - 2 0 4 0 percent 66.7 0.0 - - - - - - 100.0 0-0 21.1 0-0 Shespebead No. eamminad Is 11 3 1 2 1 2 0 1 1 1 3 5 1 2 0 7 6 15 6 2 1 3 3 61 36 No. advastcad 12 a - - - - - - - - - - - - - - - - - - - - - - 12 is Percent 66.7 72.7 - - - - - - - - - - - - - - - - - - - - - - 19.7 22.2 Atlantic No. examined 8 4 2 3 2 4 32 3 2 0 is 5 4 0 1 0 7 0 10 a 3 0 23 4 13 3 125 34 croaker No. advanced - - - - - - 2 0 - - - - 1 0 2 0 5 U Perceat - 6.3 0.0 - - - - 10.0 0.0 15.4 0.0 4.0 0.0 spot 50. examined is a 10 12 26 20 2 1 0 3 17 3 10 13 16 9 6 4 2 0 31 15 33 31 t7t 119 10. aftwashced Percent Southel's NO. examisw 15 1 12 0 9 1 9 1 11 2 3 0 1 1 9 1 32 3 1 0 21 3 15 0 138 13 kingfish No. advanced - - - - - - - - - - 2 1 - - 1 0 3 1 Percent 6.3 33.3 6.7 0.0 2.1 7-7 Advanced reproductive stag" include stages IV through VII. The sex ratios for spotted seatrout by length group in 50 mm group- ings appear in Table 41. The overall ratio of female to male seatrout collected during this study was 1.9:1. Ratios for individual length groups showed an increasingly higher ratio of females over males as length increased. In trout <250 mm males outnumbered females with ratios ranging up to 1:3. In specimens 251-350 mm the ratio was nearly equal at 1:1. However, for fish 351-400 mm females became dominant at 2.6:1. The highest ratio of females to males was for fish 501-550 mm with a ratio of 23:1. Female seatrout live longer and attain larger sizes than the males throughout the range (see age and growth section). This accounts for the higher ratio of females to males for the older and larger fish. Furthermore, since males do not generally attain the larger size they are probably more prone to capture by sport fishermen using live shrimp to fish for trout of small to moderate size. Monthly distribution of seatrout by sex and salinity gradient are presented in Table 42. Females outnumbered males during all months and at all salinity levels. The greatest monthly occurrence of males came during January (47%) and April (40%). The greatest singular concentration of males came during January in salinities of 26-30 0/oo when 41 specimens (60%) were collected. It is felt by the authors that there is probably some seasonal segregation of sexes as recreational fishermen quite often report large catches of predominantly male or female trout. However, these data do not substantiate that view. A comparision of the estuarine distribution of females and males of each fish species is presented by salinity gradient in Table 43. The general condition of the gonads of spotted seatrout were ex- amined through gross examination and all abnormalities were recorded as fish were examined for life history studies. The number and percent of female seatrout exhibiting various ovarian conditions are presented by estuarine system in Table 44. Of 788 seatrout ovaries examined, 639 (81.1%) appeared normal in all respects. The most frequently occurring abnormal condition was classified as "resorbing eggs". This condition occurred when females 76 Table 41. Sax ratio for "rim sportfishas in 50 we length groups for fish collected In the coastal wat- of Glynn County, Georgia fron Janvery 1979 through June 1962. Sex Ratio ad Mush- @.=. by Special Length Group Spotted 5, ..' Atlantic Southern sawtrout W"kfi.h Red drvio flounder dr- Sheep.head croaker spot kigfi.h 1-50 1:0 1.7:1 (16 51-100 0:1 1:2 (1) (6) 101-150 0:1 1:0 1:0 1:0 1:1 5:1 (1) (1) (1) (3) (2) (6) 151-ZOD 1:1.5 1:1 lio 1:2 3.4:1 1.3:1 2.8:1 (5) (24) (2) (3) (48) (47) (19) Zol-2" 1:3 5.3:1 3.1 1:6 I:J.4 3.5:1 1.3:1 22;1 (2$) (38) (11) (21) (19) (50) (202) (46) 251-300 1.2:1 1.4:1 3.3:1 1:1 1.9:1 3.4:1 1511 15:1 (74) (34) (26) (6) (20) (53) (16) (32) 301-350 1:1 9.5:1 I:Z 26:1 1:1 5:1 1:0 0:1 19:1 (472) (84) (3) (27) (2) (12) (3) (1) (40) 351-4W 2.6:1 47.1 1:6 16:1 1:1 7:1 1:0 6:1 (454) (9b) (7) (17) (2) (9) (1) (7) 401-450 6.0:1 1.0 1:2.7 1:0 1:2 1:1.2 1:0 (132) (18) (11) (7) (3) (11) (1) 451-500 6:J 1:0 1,11 1:1 1.6:1 (70) (1) (10) (2) (13) 501-550 23:1 1:0 4:1 1:0 1.7:1 (48) (1) (5) (a) 551-W 15:1 1:0 1:3 1:0 1:0 5:1 (32) (1) (4) (3) (1) (6) 601-650 1:0 1:0 1:0 (6) (4) (1) 631-700 1:0 1:2 1:0 (1) (3) (2) 701-750 1:0 1:1.5 1-.0 (1) (5) (1) 751-M 1:2 (3) $01-850 351-9w 1:0 (1) 901-950 (1) 951-1000 1001-IOSO 1051-11010 1:0 (2) 1101-1150 1:0 (2) 1151-1200 1:0 (2) CMIM 1.921 6:1 1:1.3 9.5tt 1:1.5 1.7:1 3.7.1 1.4:1 10.6:1 (1328) (Z") (47) (116) (47) (97) (159) (290) (151) MM: Val" within parentheses I, the amber of fish In smapt.. Table 42. Number and percent of female versus male spotted seatrout, Cynoscion nebulosus. by salinity gradient and month for fish collected In Clynn County, Georgia from January 1979 through June 1982. SURFACE WATER SALINITY (0/00) 0-5 ,6-10 11-15 16-20 21-25 26-30 31-35 36-40 TOTAL PKWTH F H F x F M -F M F-M -F - -- X - - - -M Y - -M F x January No. 8 19 60 29 27 41 5 1 100 90 z 30 70 67 33 40 60 83 17 53 47 February NO. 2 1 16 9 7 8 40 20 13 7 34 25 0 8 112 70 z 67 33 64 36 47 53 67 33 65 35 58 42 0 100 62 38 March NO. 1 0 4 1 12 5 32 17 52 28 9 2 110 53 100 0 80 20 71 29 65 35 65 35 82 18 67 33 April NO. 3 0 20 10 8 7 16 9 28 16 7 10 9 9 91 61 x 100 0 67 33 .53 7 64 36 64 36 41 59 50 50 60 40 may NO. 13 6 27 13 23 9 41 19 8 1 1 0 113 48 % 68 32 68 32 72 28 68 32 89 11 100 0 70 30 @j June No. 26 13 16 4 17 12 59 29 Cr z 67 33 80 20 59 41 67 33 July NO. 1 0 2 0 20 6 11 6 3 7 37 19 2 100 0 100 0 77 23 65 35 30 70 66 34 August NO. 2 0 11 5 8 1 5 5 26 11 z 100 a 69 31 89 11 50 50 70 30 September No. 7 1 2 2 4 0 13 5 15 8 3 1 44 17 2 88 12 50 50 100 0 72 18 65 35 75 25 72 28 October No. 1 1 11 2 22 9 14 1 2 0 50 13 z 50 50 85 15 71 29 93 7 100 0 79 21 November No. 38 4 28 12 66 16 2 90 10 70 30 80 20 December No. 9 1 51 22 5 2 1 0 66 25 z 90 10 70 30 71 29 100 0 73 27 TOTALS NO. 6 1 48 22 43 28 151 81 357 153 215 131 53 36 1 0 874 452 % 96 14 69 31 61 39 65 35 70 30 62 38 60 40 100 0 66 34 t I Table 43. Number and percent of females versus males by salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. SURFACE WATER SALINITY (0/oo) 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 TOTAL SPECIES F M F M F M F M F M F M F M F M F M Spotted NO. 6 1 48 22 43 29 151 81 357 153 215 131 53 36 1 0 874 452 *"trout z 85.7 14.3 68.6 31.4 60.6 39.4 65.1 34.9 70.0 3o.o 62.2 37.8 59.5 40.5 100.0 0.0 65.9 34.1 weakfish NO. - - - - 4 . 0 58 7 55 14 88 11 52 11 - - 257 43 z - - - - 100.0 0.0 89.2 10.8 79.7 20.3 88.9 11.1 82.5 17.5 - - 85.7 14.3 led drum NO. 1 0 - - 0 1 6 5 6 5 4 11 3 5 - - 20 27 2 100.0 0.0 - - 0.0 100.0 54.5 45.5 54.5 45.5 26.7 73.3 37.5 62.5 - - 42.6 57.4 Southern 50. - - - - 3 0 9 6 29 2 40 2 21 1 - - 102 11 flounder 2 - - - - 100.0 0.0 60.0 40.0 93.5 6.5 95.2 4.8 95.5 4.5 - - 90.3 9.7 Summer 160. - - - - - - - - - - 2 0 1 0 - - 3 0 flounder Z - - - - - - - - - - 100.0 0.0 100.0 0.0 - - 100.0 0.0 Black drum 50. - - 1 9 0 2 2 7 6 3 3 5 3 2 - - 15 28 % - - 10.0 90.0 0.0 100.0 22.2 53.8 46.2 37.5 37.5 62.5 60.0 40.0 - - 34.9 65.1 Sbeopshead NO. - - - - 5 6 2 0 24 8 10 7 6 4 14 12 61 37 2 - - - - 45.5 54.5 100.0 0.0 75.0 25.0 58.8 41.2 60.0 40.0 53.8 46.2 62.9 37.1 Atlantic 50. - - 1 0 4 1 27 7 24 12 55 13 15 2 - - 127 35 croaker z - - 100.0 0.0 80.0 20.0 79.4 20.6 66.7 33.3 80.9 19.1 88.2 11.8 - - 78.4 21.6 spot NO. - - 2 1 13 7 11 13 65 68 48 27 27 2 - - 166 118 % - - 66.7 33.3 65.0 35.0 45.8 54.2 48.9 51.1 64.0 36.0 93.1 6.9 - - 58.5 41.5 Southern NO. - - 1 0 1 0 1D 0 25 8 38 2 62 4 - - 138 14 kingfish 2 - - 100.0 0.0 100.0 0.0 100.0 0.0 75.7 24.3 95.0 5.0 94.0 6.0 - - 90.1 9.9 Gulf 50. - - - - - - - - 3 2 1 0 29 2 - - 33 4 kingfish 2 - - - - - - - - 33.3 66.7 100.0 0.0 93.8 6.3 - - 89.2 10.8 Table 44. Number and percent of various ovarian conditions for spotted seatrout, Cynoscion nebulosus, by estuarine system for fish collected in Glynn County, Georgia from January 1979 through June 1982. St. Simons St. Andrew Altamaha Combined Ovarian Condition No. % No. % No. % No. % Normal 414 80.7 220 81.8 5 83.3 639 81.1 Resorbing eggs 33 6.4 24 8.9 1 16.7 58 7.4 Atypical ovaries 35- 6.8 16 5.9 - - 51 5.7 Atrophic ovaries 6 1.2 2 0.7 8 1.0 Unequal development 8 1.6 1 0.4 9 1.1 co Fragmented ovaries 7 1.4 3 1.1 10 1.3 Fluid laden ovaries 2 0.4 - - 2 0.3 Missing oviducts 1 0.2 - - I 0.1 *Missing gonads 1 0.2 1 0.4 2 0.3 Hermaphroditic gonads 6 1.2 2 0.7 - - 8 1.0 TOTAL EXAMINED 513 100.0, 269 100.0 6 100.0 788 100.0 Adult size fish with no gonads present. NOTE: Ovarian conditions were determined by gross examination. ti failed to spawn their eggs and were physiologically trying to resorb the egg masses. This condition occurred in 7.4% of the ovaries examined. In most of these fish the ovaries appeared to be cystic and contained large hard lumps of degenerative egg mass which quite often appeared to be so severe as to result in permanent sterility (Figure 17). Whether this condition was the result of malfunction or disease is unknown. Further studies should be conducted on this particular anomaly and its causes. "Atypical ovaries" included a variety of other conditions in which the ovaries did not conform to the normal shape, size and color, and included ovaries that had become fused with other organs or mesentery. This condition was found in 5.7% of those examined. "Unequal develop- ment" between the paired ovaries of an individual fish was encountered in 1.1%, and was usually seen as only partial development in one ovary while the other ovary was in an easily recognized stage of ovarian development (Figure 18). "Fragmented ovaries" represented 1.3% and were typified by one or both ovaries being in two or more parts. Two adult size seatrout were found with no apparent gonads and were included herein. This condition occurred in only 0.3% of those examined. The most significant single sexual anomaly encountered during this study was the presence of eight hermaphroditic seatrout exhibiting various degrees of hermaphroditism (Figures 19 and 20). This condition was found in only 1.0% of the fish examined and the particular gonads exhibiting this condition were generally dominated by ovarian tissue. One fish, however, exhibited approximately 75% of each gonad being testes and 25% ovary, and both eggs and milt were clearly visible in the separate portions of each gonad (Figure 19). The two portions of each lobe of these hermaphroditic gonads were fused together. The gonads of other specimens in hermaphroditic condition were composed of pri- marily ovarian tissue which comprised over 75% of one or both gonads (Figure 20). A comparison of the frequency of occurrence for each type sexual anomaly within each estuarine system revealed less than 3% difference 81 .0 . . . . . . . . . . . . . . .11 .......... ... .......... .. . ...... . . . . ..... Figure 17. Cystic condition observed in spotted seatrout ovaries that failed to resorb the egg mass. AMR amm, Figure 18. Spotted seatrout ovaries exhibiting unequal d(--velopment and fluid laden ovaries. 82 ....... . ...... . . . . . . . .. .% . . . .. .. .. .. .. ... .. . ......... . Figure 19. Hermaphroditic spotted seatrout with gonads consisting primarily of testicular tissue. ......... .. W@ ........ ...... . IWO "INA, ... ....... PIN., . .. . .. . .. . . . ...... Figure 20. Hermaphroditic spotted geatrout with gonads consisting primarily of ovarian tissue. 83 in occurrence between the St. Simons and St. Andrew estuarine systems. No comparison is given for the Altamaha system as sample size was too small (Table 44). Fecundity of the spotted seatrout in the Gulf of Mexico was reported in Texas by Pearson (1929) and Miles (1950), in west Florida by Moody (1950), and in Louisiana by Sundararaj and Suttkus (1962). However, comparatively limited information has been published for seatrout fecun- dity on the Atlantic coast. Fecundity for seatrout collected in the Indian River area of east-central Florida was investigated by Tabb (1961). In general, fecundity estimates reported by the various investigations ranged from 15 thousand to 1.1 million eggs for spotted seatrout ranging from 283 to 625 mm (TL). Fecundity for several seatrout populations is illustrated in Figure 21. Fecundity estimates were determined for 12 Georgia spotted seatrout ranging in length, weight, and age from 325 to 533 mm, 386 to 1,871 g, and III to V years. The mean estimated fecundity was 245,990 eggs with a range from 107,300 to 468,200 eggs. Fecundity data for these 12 sea- trout are shown in Table 45. Food Preference and Feeding Habits The spotted seatrout is considered by many to be the most popular inshore sportfish from South Carolina to Texas, and has been the target of intensive investigations, including its feeding habits. Most workers agree that trout are opportunistic feeders whose food habits change with size and age (Moody, 1950; Simmons, 1957; Seagal, 1969; Peret et al., 1980). In general, the primary food for young trout is crustaceans. However, there is a general shift with age from smaller crustaceans such as copepods in the juveniles to larger commercial penaeid shrimp in small to medium sized adults. In the largest adults the diet shifts from crustaceans to primarily fishes. Pearson (1929) reported that Texas seatrout feed primarily on shrimp, and similar findings were reported by Kemp (1949), Stewart (1961) and McHugh (1980). Lorio and Schafer (1966) reported that fish were the most important food for adult Louisiana seatrout, but crustaceans were 84 1200 Pearson.(1929) Texas 1050 Tabb (1961) Florida Sundararaj and 900 Suttkus (1962) Louisiana 101 0 Present Study 0 Georgia 750 X E 600 S z "J 450 do 300 00, 150 10, 275 325 375 425 475 525 575 625 TOTAL LENGTH (MM) Figure 21. Comparison of fecundity for several populations of spotted seatrout, Cynoscion nebuZosus. 85 Table 45. Estimated fecundity for 12 spotted seatrout, Cywecion nebuLosus, collected in the coastal waters of Glynn County, Georgia during May and June of 1980. C, Year Number Total Length (mm) Mean Fish Percent Gonad Estimated Fecundity (X1000) C1% Class of Fish Mean Rang;@ Weight (g) Weight _ Mean Range 111 8 362 325 - 396 588 15.3 192.5 108.2 - 298.6 IV 3 453 419 - 491 1,120 11.1 277.2 167.9 - 433.8 V 1 533 533 1,871 16.3 468.2 468.2 Combined 12 398 225 - 533 828 14.1 246.0 108.2 - 468.2 equally important from May through July. Gunter (1945) reported that seatrout feed primarily on fish during winter in Texas. Brewer (1957) reported mullet and silversides as the top foods in Baffin Bay, Texas where shrimp are not abundant. Moody (1950) reported that seatrout feeding habits progressed through four stages from copepods to caridean shrimp to penaeid shrimp to fish in Cedar Key, Florida. Tabb (1961) suggested that food selectivity by adult seatrout in east-central Flor- ida was more a function of food availability than selectivity. Seagle (1969) found that trout over 350 mm fed mainly on fish. Mahood (1974) reported that Georgia seatrout appeared to have no definite preference and ate whatever was easiestto attain at different times of the year. From the findings of these other workers and from the results of this study it appears that spotted seatrout feed on the most available and easiest foods to attain. This is substantiated by Georgia anglers taking trout on live shrimp during warmer months from May through November and even into December when penaeid shrimp are available. As water temperatures drop sharply in December, penaeid shrimp become less abundant as they migrate offshore and southward. During winter most anglers shift to artificial lures to catch seatrout as small fish become the most available food source. Our findings from stomach analyses of seatrout collected during this study are presented below. Of the 1,359 spotted seatrout stomachs examined during this study, 874 (64.3%) contained food and 485 (35.7%) were empty (Table 46). Food items identified in the stomachs of seatrout per 100 mm length group are presented in Table 47. In juvenile seatrout (<200 mm) the most commonly occurring food source was crustaceans of which grass shrimp (PaZemonetes sp.) occurred most frequently. As seatrout increased in size, they began to feed more frequently on fish as evidenced by the increasingly higher occurrence of fish in the stomachs of creel size specimens (301-500 mm). In this size group menhaden (Brevoortia sp.) were the most frequently ingested species of fish,and white shrimp (Penaeus setiferus) were the most commonly observed crustacean.. After seatrout reached 600 mm, their feeding habits apparently changed 87 Table 46. Number and percent of empty stomachs versus those containing food for fish roll-ected in Glynn County, Georgia from January 1979 through June 1982. Empty Stomachs Contain Food Total Stomachs No. % No. No. Spotted seatrout 485 35.7 874 64.3 1,359 100.0 Weakfish 86 26.4 240 73.6 326 100.0 Red drum 22 23.4 72 7 6.6 94 100.0 00 CO Southern flounder 108 48.9 113 51.1 221 100.0 Summer flounder 4 14.8 23 85.2 27 100.0 Black drum 15 19.5 62 80.5 77 100.0 Sheepshead 15 12.8 102 87.2 117 100.0 Atlantic croaker 31 11.6 236 88.4 267 100.0 Spot 39 12.1 282 87.9 321 100.0 Southern kingfish 38 16.8 188 83.2 226 100.0 Gulf kingfish 7 20.0 28 80.0 35 100.0 10 0 to 41 Ah a a Table 47. Stomach contents of Spotted seatrout, C@WBCiOn nebULOBUB, collected in Glynn County, Georgia from January 1979 through June 1982. Length Group, W Percent Average Food Iten 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701- 00 Combined Occurrence % bolus PISCES Pisces (unidentifiable) 4 27 253 59 19 2 1 365 41.8 76 Anchoa hepsetus I I 0.1 30 Anchoa mitchitti 2 6 1 9 1.0 66 Bmwortia tyz-wmus 10 119 30 16 1 176 20.1 87 Chloroacombrus chry8urus I 1 2 0.2 90 Cynoscion nebuloeus I I 0.1 90 C) C@prinodon variegatus I I 0.1 30 Fwmfulue heteroclitus 5 11 1 17 1.9 82 Leioctomue =mthurus I 1 2 4 0.4 90 Afenidia menidia 10 I 11 1.3 82 Nenticirrhw awricanue I I 0.1 90 migil oephalus 7 6 6 1 20 1.0 88 Opsmus tau I 1 2.3 70 Paralichthya Zethostigm I I 0.1 90 S&i,aenops oceZZatue 7 1 1 9 3.1 83 Stellifer Umaeolatus I 18 1 20 2.3 85 SIpThuzw plagiuea I I 0.1 90 Syngnathidae 2 2 o.2 30 Table 47. (continued) Food Item 1-100 101-200 ------Aaqsth Grou -p (m) Percent Average 201-366 -301-400 401-500 501-600 601-700 701-800 Combined Occurrence Z Bolus ARTHROPODA Crust&cea (unidentifiable) 4 9 59 7 1 80 9.2 60 Atpheue heterochelis 1 1 18 5 1 26 3.o 64 Aophipoda 2 2 0.2 <10 Anthuridae, 3 2 1 6 0.7 43 Azwnaeus cribraz-ius 2 2 0.2 <5 Athropoda 2 2 O.i 45 C4pepoda 2 2 0.2 45 Crangan aept-owpiwea 1 1 0.1 < -1 C@athura potita 2 2 1 5 0.6 40 Dec'spoda 1 1 5 38 3 1 49 5.6 76 Diastylidae, 1 1 0.1 <5 Gwmr.2rus mucronatue 1 1 0.1 <.O Insects I 1 0.1 10 Isopoda 3 8 1.3 16 Neomyeie apwricam 1 10 1.3 5@ OwZipee ooellatua 1 0.1 70 Oxyurostylia smithi 1 0.1 10 Pagu- L-gicarp- 1 3 4 0.4 43 Phlaewnetes sp. 10 4 47 4 1 66 7.6 68 Fenaeidam, 3 27 2 1 33 3.b 63 FVnaeus axtema 2 2 4 0.4 55 Penaeus duorarwn I 1 1 3 0.3 50 Fenaeue oetiferus 3 57 3 63 7.2 80 Sesarma cinerewn I 1 0.1 90 Sicyonia sp. I 1 0.1 20 T-rachypeneus constrictus 1 10 1 12 1.4 68 Yea pugnax 0.1 10 t I Ak Table 47. (continued) Length Group (m) Percent Average Food Item 1-100 101-200 201-300 301-400 401-500 501-600 601-700 701-800 Combined Occurrence % Bolus WDLLUSCA Mollusca (unidentifiable) I 1 0.1 50 Cmasostrea virginica 1 1 0.1 10 Gastropoda I 1 0.1 90 CKFHALOPODA Cepbalopoda. (unidentifiable) 4 2 6 0.7 42 Lolligwscula brevis 10 1 11 f.3 54' ANNELIDA and ASCHELME??THES Aegothoa 8P. 2 2 0.2 10 Glyceridae' 1 1 0.1 90 Glycindae aolitar-ia 1 1 0.1 90 2 2 0.2 <5 Nesatoda Nereidae I 1 0.1 90 Niooua simplex 3 1 4 0.4 35 Rhynchocels 4 4 0.4 28 PLANT Detritus 1 4 1 6 0.6 50 Spartina a7tez-nifZora 2 6 4 12 1.4 58 CNIDARIA Anthozoa I 1 0.1 <5 UROCHORDATA Motgula mouNattensis I 1 0.1 <5 INORGANIC MATERIAL 2 1 11 14 1.5 65 ANIMAL TISSUE (unidentifiable) 0.1 90 Number of stomachs: 1359 Number and percent of stomachs containing food: 874 (64.3%) Ember and percent of empty stomachs: 485 (35.7%) to a purely piscivorous diet. Similar results were found in Laguna Madre, Texas by Simmons (1957). The preference of fish in the stomachs of large adults accounts for the relatively low number of large trout in daily creels because the preferred bait by Georgia anglers is live penaeid shrimp. All species of fish identified in stomach contents comprised over 66% of the average food bolus except for Anchoa hepsetus, Cyprinodon variegatus, and pipefish (Syngnathus sp.). The relatively small size of these three species probably accounts for their low contribution to average percent of bolus. Penaeid shrimp were the most frequently occur- ring crustacean, averaging 50% of food bolus when encountered (Table 47). Penaeids are the largest commonly occurring shrimp in Georgia waters, which would account for this high percent of bolus. The 10 most frequently occurring food items by season and sector are presented in Table 48. Fish and fish parts were the most commonly encountered food items in trout stomachs in all seasons and sectors and menhaden were the most frequently occurring species. The most commonly ingested crustacean during winter and spring was grass shrimp (PaZae- monetes sp.), but during summer and fall, white. shrimp (Penaeus setiferus) became dominant. Furthermore, during fall white shrimp were observed in the stomachs even more frequently than menhaden. It has been determined in other studies that it takes four to five hours for sea catfish (Arius feZis) and Atlantic croaker (Micropogonias unduZatus) to digest brown shrimp (Penaeus aztecus) to an unrecognizable state (Divita et al., 1981: Cited in Creel and Divita, 1982). It was also determined that total digestion of mullet by spotted seatrout could take from two to three days (Guest and Gunter, 1958). DeCiechomski (1981) conducted controlled laboratory experiments on the digestion rates of shrimp in juvenile sciaenids off Argentina and found that 32-38% of the food (shrimp) was evacuated from the stomach after 4 to 6 hours from meal ingestion and after 14 hours the percentage jumped to 87%. Assuming that digestion rates for seatrout are comparable with that of sea catfish and croakers and other sciaenids, it would require only a matter of hours to digest shrimp to an unrecognizable state as 92 Tobin 48. The 10 wet frequ,ently occurring food items found In the stomachs of spotted seatro,t. e- 1@ b@ --. ..d -wr f,,, fish collected In Gly" County, Georgia frow January 1979 thr,ugh June 1982. --Winter Spring S-r Mo. Percent Average Mo. Percent Average MD. Percent A-rsge Sector Food Itm stoso@h. Occ,urreace, ISol" food Item Stomachs occurrence 2 Solue, Food Ites Stosa.;@s Occurrcme Creaft Pisces 73 38.2 so pieces 65 47.8 78 Pieces 17 53.1 62 B ty@ 36 18.8 87 B@rtia ty@a 52 38.2 as B-ti@ ty-- 15 46.9 90 Heit-ti. 23 12.0 79 pul.@ t- op. 11 8.1 61 Crustacea 12 37.5 52 Cewstacea is 7.9 67 Crust- to 7.4 48 P,__ -tif-, 7 21.9 54 ponx,ems so,tifrus 12 6.3 as Decepd. 6 4.4 40 Penatid- 7 21.9 50 A@phems Pwillet- 11 5.6 60 Alpheus amillet@ 4 Z.9 65 mugil ,Ph@!_ 5 15.6 84 palaememet.. op. 10 5.2 77 PIO.Euzue h@t-litus 3 2.2 73 Fud@l- ilt-lit- 4 12.5 90 Pacmeeidam, 7 3.7 60 P-aeme ectife@ 3 2.2 63 P.__ d___ 3 9.4 50 Stollif., 7 3.7 so Unidevitifled motterial 3 2.2 47 SI-ti- alt-ifl- 3 9.4 4o M,gil cephalue 4 2.1 90 Isopods 3 2.2 43 [email protected]_ p'lita 3 9.4 33 SO.". PI.- 34 32.1 84 piece. 51 51.0 72 pieces 11 34.4 40- pdl@t.. op. 27 25.5 79 B@voo,ti. ry_@ 27 27,0 as 3-ooortf'. ty- 6 18.8 90 Matmoti. 16 15.1 70 Crumitaces 9 9.0 63 ?,-- .,tif,@ 6 18.8 87 DO.-P-do 13 12.3 85 munidi. -idi. 7 7.0 77 Fumd@l- het.-lit- 4 12.5 75 Vj. idne, 9 8.5 67 paza-tes op. 6 6.0 62 loopods 3 9.4 7 A4A.- heteroch.Lia 7 6.6 77 Spa,ti- 4.0 73 )A4G 1 2 6.3 90 Uaidwtified mteri&I 4 3.8 68 S-11ir., 1-1.t- 2 2.0 90 1.,, 7, b-,i. 2 6.3 70 Bro,wo-tia ty@ 3 2.6 90 Cephalopod,, 2 2.0 90 puz=t- up. 2 6.3 60 StelLife, Z@cztuo 3 2.8 90 Dec.pd. 2 2.0 75 stezif- Z-1.t- 1 3.1 90 Aienidi. m.,rCdia 1 0.9 9ko L-11ij-1. b-i@ 2 2.0 50 P-idae 1 3.1 90 Insche's Pisces 2 100.0 50 Pisces 41 68.3 86 Etellif- [email protected] 5 36.4 86 Biwo .. tia ty-cus 1 50.0 100 BY`c0-1ti- t4--- 10 16.7 90 Pisces a 36.4 43 P.I@te. op. 5 8.3 40 B@'ti. ty@ 2 9.1 90 An,h- ith,11i 4 6.7 70 A-h- [email protected] 1 4.5 9-0 St.11i"c' 3 5.0 63 syoph@ plqyi@. 1 4.5 90 Ratantia 3 5.0 40 ChI.M.-Whms AY,@ 1 4.5 90 C.Ph.l.p.d. 2 3.3 25 puz@_@. op. 1 4.5 90 Glyc,i.d@, -lit-i. 1 1.7 90 Decapoda 1 4.5 90 '@tiw .1e,_ifzO_ 1 1.7 90 Gentrupoda 1 4.5 90 Animist ties- 1 1.7 9-0 Memotd. 1 4.5 5 Offshore =av - - NOKE - - - NONE - - - Totalm Pisces 109 36.5 at pieces 157 53.0 78 Pisces 36 31.6 51 B"vWrtia tyravacus 40 13.4 as B_v-,ti@ ty__@ 89 30.1 86 B-owni. ty- 23 20.2 9-0 phl@et- sp. 37 12.4 78 Pta-t- op. 22 7.4 56 P,__ setife-e 13 11.4 69 Decop.d- 36 12.0 eI C_t__ 22 7.4 53 C_tc_ 12 10.5 52 c1restac"' 31 10.4 68 Dcspd. 9 3.0 so Stcllif@, Z-1at- 9 7.9 97 Alph@ hoterooOteli. is 6.0 67 [email protected]. -nidi. a 2.7 79 Pmdluz hter-lit- a 7.0 93 Penao," setiferus 13 4.3 ft L;,@tim altemiflom 7 2.4 70 P-ide 8 7.0 51 wj.id" 9 3.0 67 Anoh@ mitchelli 6 2.0 53 14,gil -ph.1- 7 6.1 36 U."emitified not.rial 5 2.7 70 Cephalopoda 5 1.7 46 PuLaaw-t- op. 4 3.5 60 St,rzlif" Z@wzdtus 7 2.3 81 Iwpods 5 1.7 30 looped. 4 3.5 ymne, d0ent" so opwiseftne wem collseted with food In stommoths. Table 48. (continued) Fall Combined Totals No. Percent Average Percent Average Sector Food Item Stomachs Occurrence Z Bolus Food Item Stomachs Occurrence % B,lus Creeks Pisces 36 35.0 78 Pisces 191 39.0 77 Pcnac-UL; ;Gtiferuz 21 20.4 94 Rrevoort@a tyry2nnus 123 25.1 87 Bmv@urtiu tyrannuL 20 19.4 88 Crustacea 44 9.0 59 Penacidae 14 13.6 68 Penaeus setifey-us 43 8.8 79 Crustacea 7 6.8 71 Decapoda 32 6.5 73 Nugi, ""ph2lus 5 4.9 98 Penaeidae 29 5.9 62 Funduluz h., terocLitus 3 2.9 so Palaemonetes sp. 25 5.1 62 Alph,:us sp. 3 2.9 .37 Alpheus heterochelis is 3.7 57 Palae.,*.@net" sp. 3 2.9 30 Mugil cephalus 14 2.9 87 Pundulus heteroclitus 12 2.4 83 Sounds Pisces 24 44.4 75 PiRces 120 41.1 73 Pe@eua setif@rus 11 20.4 85 Brevoortia tyrannus 39 13.4 88 Crustacea 7 13.0 53 Palaemnetns sp. 35 12.0 75 Trachypeneus onstrictuo 5 9.3 78 Crustacea 32 11.0 64 Auji, cephalu- 3 5.6 90 Penneus setiferus 19 6.5 83 Brc7x@jrtia tyrannus 3 5.6 80 Decapoda 15 5.1 83 Penaeidae 3 5.6 63 " Idac 9 3.1 67 LoZliguncu2a bmvis 3 5.6 53 Alphpus hPterochelis 8 2.7 79 Organic materials 2 3.7 10 Menidia menidia 8 2.7 79 Alpheuc sp. 1 1.9 90 Lolliguwul brevis 7 2.4 57 J-1 Beaches Pisces 3 37.5 67 Pisces 54 58.7 77 Penaeus setiferus 1 12.5 90 BreLk>ortia kyrannus 14 15.2 98 Wnidia menidia 1 12.5 90 SteLlifer lanceolatus 12 13.0 al Stellifer lanceolatus 1 12.5 90 Pala,-munptes sp. 6 6.5 48 Penaeus azte@-us 1 12.5 90 Anchoa mitchilli 5 5.4 74 W Iliguncula brevis 1 12.5 80 Crustacea A 4.3 40 Brevoortia tyrnnnus 1 12.5 60 Decapoda 2 2.2 75 Crustacea 1 12.5 40 Cephalopoda 2 2.2 25 Symphurus plagiuso 1 1.1 90 Peruzeus setiferus 1 1.1 90 Offshore NONE NONE - - - Totals Places 68 38.2 76 Pisces 365 41.8 76 Penaeus setiferus 33 20.0 85 Brevoortia tyrannus 176 20.1 87 Brevoortia tyrannue 24 14.5 86 Crustacea 80 9.2 60 Penaeldae 17 10.3 67 Palaemonetes sp. 66 7.6 68 Crustacea 15 9.1 61 Ppnapus setiferus 63 7.2 80 Mugil cephalus 8 4.8 89 Decapoda 49 5.6 76 75-achypeneus conatrictua 8 4.8 83 Penseldae 33 3.8 63 Lolliguncula brevis 6 3.6 48 Alpheus sp. 26 3.0 64 Alpheus sp. 4 2.4 50 Mkqil cepholus 20 2.3 88 Stellifer lanceolatua 3 1.8 90 SteNifer lancrolatus 20 2.3 85 None denotes no specimens were c'ollected with food ir. stomachs. opposed to a matter of days to digest fish. One would, therefore, expect to find fish and fish parts such as vertebrae and scales much more frequently in the stomach contents of seatrout even if crustaceans are the preferred food item. The number and percent of stomachs containing food versus empty stomachs by season and sector are presented in Table 49. During spring and summer approximately 72% of the stomachs examined contained food. The percentage dropped sharply to 65.2% in fall and was lowest during winter at 55.9%. The beaches apparently had less available food supply as 43.2% of all stomachs from this sector were empty. Food availability on the beaches was lowest during winter as 81.8% of the stomaches were empty. However, since trout are less abundant on the beaches during winter, these results are from a limited sample. Low availability of food along the beaches in winter probably accounts for a major influence in seasonal movement of se@trout to the creeks and rivers in search of food as well as for refuge from the cold. However, extremely cold water temperatures often congregate trout in deeper water in the creeks and rivers as evidenced in trawl catches and recreational creels. A comparison of the number of stomachs containing food versus empty stomachs by water temperature appears in Table 50. It appears that food was either less available or feeding activity slowed down when water temperature dropped below 15 0C as approximately 45% of the stomachs ex- amined were empty. When temperatures exceeded 160C no more than 32% of the stomachs examined were empty at any temperature range. The number and percent of stomachs containing food versus empty stomachs according to moon phase are presented in Table 51. The periods of highest feeding activity apparently occurred on intermediate days between major moon phases. During these "split phases", 73.8% of the stomachs contained food. There was an 11.5% higher occurrence of stomachs containing food during split phases than for the overall average of 64.3%. Feeding activity was also high during the week of last quarter from three days prior to and three days after last quarter. Feeding activity was the lowest during new moon and the three day period imme- 95 oe Table 49. Number and percent of spotted seatrout, Cynscion nebulosus, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Yo-tal Food Empty Ti;ti-al Food Empty Total Z No. % No. % No. % No. Z No. X No. Z No. 2 No. z Winter 191 56.2 149 43.8 340 100.0 106 57.6 78 42.4 184 100.0 2 18.2 9 81.8 11 100.0 Spring 136 77.3 40 22.7 176 100.0 100 74.1 35 25.9 135 100.0 60 58.3 43 41.7 103 100.0 Summer 60 81.1 14 18.9 74 100'.0 32 66.7 16 33.3 48 100.0 22 62.9 13 37.1 35 100.0 Fall 103 69.6 45 30.4 148 100.0 54 58.7 38 41.3 92 100.0 8 61.5 5 38.5 13 100.0 Total 490 66.4 248 33.6 738 100.0 292 63.6 167 36.4 459 loo.o 92 56.8 70 43.2 162 100.0 %C Offshore Combined Sectors Food Empty Total Food Empty Total z No. No. % No. Z NO. No. Winter 299 55.9 236 44.1 535 100.0 Spring 296 71.5 118 28.5 414 100.0 Su=er 114 72.6 52 33.1 157 100.0 Fall 165 65.2 88 34.8 253 ioo.o Total 874 64.3 485 35.7 1359 100.0 db 0 0 Table SO. number and percent of stomacbe containing food "two empty stomachs by specl*m aod surface "ter temperature for flab collected La GIYM County. GoorsLa from January 1979 tbromo June 19112. Surface Water Temperature (00 45-16 it-is tf@20 21-25 26-30 11-35 Combined Species no. M Spotted emetrvut Food 173 56.2 126 53.6 166 70.0 206 72.3 159 68.0 14 87.5 874 64.3 Empty 135 43.8 109 46.4 71 30.0 79 27.7 89 32.0 2 12.5 48S 35 7 Total )w 1002 235 1002 237 1002 285 too-. 278 100% 16 ION 1359 100% N&WL*b Food 25 59.5 40 511.0 42 64.6 40 93.0 56 86.9 37 94.0 240 73.6 Empty 17 40.5 29 42.0 23 35.4 3 7.0 7 11.1 7 16.0 86 26.4 Total 42 100% 69 1002 65 1002 43 1002 63 1002 44 100% 326 1002 Med drum Food I 1 64.6 1 100.9 0 0.0 13 92.9 74.6 3 100.0 72 76.6 Empty 5 11.2 0 0.0 1 100.0 1 7.1 15 25.4 0 0.0 22 23.4 Tow 16 1002 1 1002 1 Ion 14 looz 59 1002 3 looz 94 100Z So"bots flawAsT Food a 39.1 9 45.0 4 66.1 a 57.1 54.2 20 4.7.6 113 51.1 Empty 13 61.9 11 55.0 2 33.3 6 42.9 54 45.9 22 52.4 log 46.9 Total 21 LOU 20 1002 6 LOU 14 LOU lie 100Z 42 looz 221 1007 Summer flounder Food 7 S7.5 1 50.0 6 75.0 3 100.0 6 10G.0 - - 23 85.2 Empty 1 12.5 1 50.0 2 25.0 0 0.0 0 0.0 - - 4 14.8 TOW a 100% 2 1002 a louz 3 LOU% 6 100% - 27 IU02 Black drum read 6 A.$ 4 11.3 to 100.0 12 100.0 30 93.7 - 62 S0.5 Empty 5 45.5 a ".7 0 0.0 0 0.0 2 6.3 - 15 19.5 Total 11 1002 12 1002 10 1002 12 1002 32 100% - 77 1002 Sbo@Psbaw Food 3 100.0 $ 71.4 22 91.7 34 35.0 35 87.5 3 100.0 102 97.2 Empty a 0.0 1 26. b 2 8.3 6 15.0 5 12.5 0 0.0 15 12.8 TOW 3 1002 7 Ion 24 IODZ 40 Ion 40 1002 3 looz 117 100% Aclastic croaker Food 4 100.0 16 U.9 9 100.0 25 $3.3 133 87.5 49 90.7 236 U.4 Empty 0 -0.0 2 11.1 0 0.0 5 16.7 19 12.5 5 9.3 31 11.6 Total 4. too% is ION 9 1002 30 1001 152 tooz 54 100% 267 looz spot wood 9 100.0 45 75.0 74 90.7 45 75.0 67 90.6 22 100.0 282 87.9 Marty 0 0.0 is 25.0 1 1.3 14 25.0 9 9.4 0 0.0 39 12.1 Total 9 1002 60 1002 75 ION 59 1002 1002 22 1001 321 too% Southern klogfisk Food 2 66.7 59 90.8 47 85.5 23 79.3 47 77.0 10 76.9 L98 83.2 Empty 1 33.3 6 9.2 a 14.5 6 20.7 14 23A 3 23.1 38 16.8 Total 3 looz 65 1002 55 1002 29 1001 61 1002 13 1002 226 100% Get( kiftiLob row - 2 ".7 1 100.0 3 100.0 22 78.6 28 $0.0 Empty 1 33.3 0 0.0 0 0.0 6 21.4 7 20.0 Total 3 looz 1 1002 3 LOU 28 looz 35 ION Table 51. Number and percent of stomachs containing food versus empty stomachs for each species by won phase for fish collected in Glynn County, Georgia from January 1979 through June 1982. 3 Days Ne@ 3 Days 3 Days First 3 Days 3 Days Full 3 Days 3 Days Last 3 Days Split Combined Prior Moon After Prior Quarte@ After Prior Moon -AL= Pr"r Phas.k Total Mono Phases i7o % N-o I W-T No. N-o-.--l 70- , % -No-.% N % 1@7-i V. -r -11-r-, ZAILI@ z spotted Food 107 58.5 33 44.6 21 50.0 88 74.6 19 48.7 31 59.6 76 61.3 18 62.1 121 65.8 98 69.5 11 100.0 147 66.5 104 73 8 874 t,4. 3 seatrout Empty 76 41.5 41 55.4 21 50.0 30 25.4 20 51.3 21 40.4 48 38.7 11 37.9 63 34.2 43 30.5 - - 74 33.5 37 26*2 485 35.7 Total 183 100.0 74 IDO.0 42 100.0 118 100.0 39 100.0 52 IDO.0 124 100.0 29 100.0 184 100.0 141 1DO.0 11 100.0 221 100.0 141 100.0 1359 100. 0 Weakfiab Food 37 75.5 - - 3 75.D 30 69.8 11 91.7 30 83.3 7 77.8 12 54.5 27 54.0 45 90.0 - - 27 77.1 11 78.6 21.0 73.b Empty 12 24.5 1 100.0 1 25.0 13 30.2 1 8.3 6 16.7 2 22.2 10 45.5 23 46.0 5 10.0 1 100.0 8 22.9 3 21.4 86 2h.@ Total 49 100.0 1 100.0 4 100.0 43 IDO.0 12 100.0 36 100.0 9 100.0 22 100.0 50 IDO.0 50 100.0 1 100.0 35 100.0 14 100.0 326 100.0 Omd drum Food 8 98.9 3 50.0 - - 6 75.0 - - 4 100.0 11 100.. u 2 66.7 8 80.0 5 55.6 8 72.7 8 72.7 9 75.U 72 76.6 Empty 1 11.1 3 50.0 - - 2 25.0 - - - - - - 1 33.3 2 20.0 4 44.4 3 27.3 3 27.3 3 25.0 22 23.4 Total 9 100.0 6 100.0 - - a 100.0 4 100.0 11 14)t). 1, 3 100.0 10 100,0 9 IDO.0 11 joo,o 11 IDO.0 12 100.0 94 100. 0 Southern Food 33 68.8 1 33.3 5 38.5 20 52.6 - - 9 75.0 1 20.0 1 33.3 9 47.4 3 42.9 2 66.7 22 43.1 7 46.7 113 51.1 flounder Empty 15 31.2 2 66.7 8 61.5 18 47.4 4 100.0 3 25.0 4 80.0 2 66.7 10 5 2. t. 4 57.1 1 33.3 29 56.9 8 53.3 108 48.9 Total 48 100.0 3 100.0 13 100.0 38 100.0 4 100.0 12 100.0 5 100.0 3 IDO.0 19 100.0 7 100.0 3 100.0 51 100.0 15 100.0 221 100.0 Summer Food - - - - - - - - - - - - 4 100.0 - - - - 3 100.0 - - 13 81.3 3 100.0 23 85.2 flounder Empty - - - - - - - - - - - - - - 2 100.0 - - - - - - 3 18.7 - - 4 14.8 Total - - - - - - - - - - - - 4 100.0 2 100.0 - - 3 100.0 - - 16 100.0 3 100.0 27 IUU.U slack drum Food 14 93.3 3 100.0 - - 11 100.0 - - 6 50.0 a 88.9 - - 4 66.7 2 100.0 1 100.0 7 70.0 6 85.7 62 80.5 C Empty 1 6.7 - - 1 100.0 - - - - 6 50.0 1 11.1 - - 2 33.3 - - - - 3 30.0 1 14.3 15 19.5 Total 15 100.0 3 100.0 1 100.0 11 100.0 - - 12 100.0 9 100.0 - - 6 100.0 2 100.0 1 100.0 10 100.0 7 100.0 77 100.0 Sbeepshead Food 23 79.3 3 75.0 2 100.0 4 80.0 1 50.0 4 100.0 10 7b.9 5 71.4 13 100.0 24 100.0 7 100.0 5 71.4 101 86.3 Empty -6 20.7 1 25.0 - - 1 20.0 1 50.0 - - 3 23.1 2 28.6 - - - - - - 2 28.6 lb 13.7 Total 29 100.0 4 100.0 2 100.0 5 100.0 2 100.0 4 100.0 13 loo.o 7 100.0 13 100.0 24 100.0 7 100.0 7 100.0 117 100.0 Atlantic Food 10 76.9 4 90.0 10 100.0 49 90.7 31 100.0 33 86.8 3 60.0 3 100.0 17 89.5 31 33.6 3 100.0 22 75.9 20 90.0 236 88.- croaker Empty 3 23.1 1 20.0 - - 5 9.3 - - 5 13.2 2 40.0 - - 2 10.5 4 11.4 - - 7 24.1 2 9.1 31 11.6 Total 13 100.0 5 100.0 10 100.0 54 100.0 31 100.0 38 100.0 5 100.0 3 100.0 19 100.0 35 100.0 3 100.0 29 100.0 22 100.0 267 100.0 spot Food 10 38.5 - - 15 76.9 64 100.0 2 66.7 5 100.0 20 100.0 23 100.0 21 77.8 10 1 UO. U 2 100.0 52 96.3 58 90.6 282 87.9 Empty 16 61.5 4 100.0 4 21.1 - - 1 33.3 - - - - - - 6 22.2 - - - - 2 3.7 6 9.4 39 12.1 Total 26 100.0 4 100.0 19 100.0 64 100.0 3 100.0 5 100.0 20 100.0 23 100.0 27 LOD .0 10 100.0 2 100.0 54 LOO.0 64 100.0 321 100.0 Southern Food 21 91.3 - - 9 75.0 16 84.2 8 $0.0 19 76.0 10 83.3 2 66.7 33 86.8 34 91.9 1 100.0 24 80.0 11 68.8 188 83.2 kixkgfisb Empty 2 8.7 - - 3 25.0 3 15.8 2 20.0 6 24.0 2 16.7 1 33.3 5 13.2 3 8.1 - - 6 20.0 5 31.3 38 16.8 Total 23 100.0 - - 12 100.0 19 100.0 10 100.0 25 100.0 12 100.0 3 100.0 38 100.0 37 100.0 1 100.0 30 100.0 16 - 226 100.0 Gulf Food - - - - 1 100.0 - - 1 100.0 1 100.0 - - - - - - - - 25 78.1 - - 28 8u.0 kingfish Empty - - - - 7 21.9 - - 7 20.0 Total - - - - 1 100.0 - - 1 100.0 1 100.0 - - - - - - - - - 32 100.0 - - 35 100.0 Combined food 263 67.6 47 47.0 66 63.5 288 80.0 73 71.6 143 75.3 150 70.8 66 69.5 253 69.1 257 60.1 28 84.8 356 71.5 237 7..0 2227 72.3 Species Empty 132 33.4 53 53.0 38 36.5 72 20.0 29 28.4 47 24.7 62 29.2 29 30.5 IL3 30.9 64 19.9 5 15.2 142 28.5 67 22.0 853 27.7 Total 395 100.0 100 100.0 104 IDO.D 360 100.0 102 100.0 t9O 100.0 212 100.0 95 1DO.0 366 100.0 321 100.0 33 JDO.O 498 100.0 304 100.0 3080 100.0 diately thereafter. During new moon the high turbidity created by in- creased tidal amplitude and current flow, coupled with a vastly increased refuge area created by inundated saltmarshes, probably resulted in making prey more difficult to detect and capture. Our findings did not indicate any trends in feeding activity as W related by barometric pressure. The 10 most commonly occurring organisms, identified to species level of classification, collected during the five minute trawl samples for all seasons and sectors combined included Anchoa mitchilZi, Micro- pogonias unduZatus, Penaeus setiferus, LoZZinguncuZa brevis, Trachypeneus constrictus, Acetes =ericanus, Callinectes sapidus, Syraphurua plagiusa, Cynoscion regaZis, and SteZZifer ZanceoZatus. Although individuals be- longing to the orders Isopoda and Mysidae were abundant, limited effort was placed on the identification of these members due to the numerous species collected and difficulty associated with identification. However, other groups such as members of the genus, PaZemonetes were collectively identified and determined to be the fourth most commonly occurring trawl organism. Table 52 lists the trawl collected organisms by season, and Table 53 lists the organisms by sector. Of the three most commonly encountered items identified in seatrout stomachs, Brevoortia tyrannus was the most abundant food item but only the 15th most abundant fish species collected in trawls (Table 54). Such occurrences of B. tyrannus indicate an active feeding preference for this species as opposed to random feeding. PaZaemonetes sp. and Penaeus setiferus were the second and third most commonly occurring food items in seatrout stomachs and also the second and third most common crustaceans collected in trawl samples. Such occurrences of these crustaceans indicate random feeding behavior. However, it should be noted that the trawl is a bottom sampling gear which may bias data by collecting primarily bottom oriented organisms as opposed to upper column or surface water organisms. Furthermore, many fish species may be capable of avoiding capture with trawls. Also, many spotted seatrout were collected adjacent to oyster reefs where trawl sampling is very 0i difficult. Thus, conclusions drawn from comparisons of stomach contents 99 Table 52. Seasonal occurrence of organisms collected with trawl from the coastal waters of Glynn County, Georgia fr. January 1979 through June 1960. Number Collected Number Collected Orlanism Winter Spring Summer Fall Total Organism Winter Spring Sumer Fall Total PISCES Larimus f"aiatus 2 5 7 Anchoa hepsetke 1 10 it Leiostomus =mthurue 22 28 6 56 Anchoa witehitZi 75 102 50 39 266 Menidia menidia 15 1 16 kwyZopeetta guadrocellata 7 5 12 menticirrhus awricanue 2 14 20 5 41 Anguilla metrata 12 1 1 14 Mentic-irrhus zittoralis I I Arius feZis 7 6- 6 19 Wcropogonias w%dutatus 66 74 18 30 188 Astrosoopue y-graemm 3 3 6 monacanthus hispidus 5 5 Bagre mm-inus 1 4 5 10 Mugil cephalus 1 2 3 BairdieZZa chrysoura 9 9 9 6 33 Ophichtus ophis 1 4 3 8 82%evoortia twnovw 6 11 1 18 ophidion mw-ginatwn 3 15 1 2 21 carw= hippoa I I Opeanue tau I 1 1 3 0 Centropristie philadelphica 2 2 Pdralichthys dentatue 1 3 4 0 Chaetodipterus faber 4 8 1 13 Paralichthys Uthostigma I I CftiLmWoterua schoopfi 3 3 PepriZue alepidotue 2 1 3 Chtorosoombrus chryourue 1 6 4 11 Pomtomus saZtatrix 1 3 4 Citharichthys spilopterus 2 2 Prionotus evoUns 4 4 cynosaiOn nothus 2 5 2 9 Prionctus op. 7 27 3 5 42 Cynosoion regalia 31 36 11 78 Sciaenope ocellatus I I slope sauna 1 11 12 scophthalmus aquosus I 1 1 3 etropus M-0880tke 3 3 14 6 26 selew vowr 7 2 9 Adoinostow guza 1 1 Sphy- guachancho I I ftn&lue heteroditue 2 2 Stellifer lanceotatuS 19 20 14 11 64 Cvbiosoma bovoi I I S@Vhurue plagiusa 20 33 20 17 90 Gobioides brousoonneti 2 7 3 12 Syugnathidae 6 7 2 2 17 BypsobUnnius hentxi I I Synadus foete" 1 1 retalurms catus 1 1 2 Tzwhinotus caroZinue 2 2 LagoosphaZus laevigatue 12 4 3 19 Trinectee macutatue 14 9 1 23 Lagodon rhomboides I I Urophycia regia 4 4 @ I I F 4 F Table 52. (continued) Umber Collected Number Collected Organiss Winter Spring Sumer Fall Total. Organisa winter Spring Sumer Fall Total ARTHROPODA Penaeu8 setiferus 35 36 36 27 134 Acetes americanus 20 37 30 24 III Portimus gibbesii I 1 Atpheus heterooheLia 8 8 2 3 21 Pycnogouida 3 Amphipoda 2 2 Sesamn reticulatwn I Anthuridae 7 2 9 Sicyonia op. 2 2 Arenaeue cribrw-ius I 1 Squilla empusa 1 12 8 1 22 Callinectes sapidus 27 35 19 16 97 Trachypeneus wnstrictus 9 58 29 22 118 Cmimr irmratus 2 2 4 Uca pugilator 1 2 CerWus tubulariua I I MEROSTOMATA Chthawtus fragilis I I Limutue polyphemus I I Copepods 13 4 2 2 21 MLLUSCA Crangon eeptempinoea I I Anachi8 avara I I Gwwww mucronatus 4 4 Buaycon canaliaulat&m 2 2 t.,j H"tus epheliticus 35 19 1 4 59 n-assoetrea virginica 6 2 8 Hexapwwpeus ariguatifrona I I Eupleura caudata 1 1 Hippolyawta wurdemanni 4 6 10 Merc@ mercenaria 1 4 5 10 Idotea op. I I Modiotus demiasus 2 2 lsopoda 50 81 11 16 158 Nassarius obeoletuo I I Libinia emarginata 2 2 2 1 7 Nassay-ius vibez 26 21 7 5 59 Mvnippe mercerwaria 1 2 2 1 6 Nudibranchia 3 2 5 Mysidae 70 43 4 11 128 Terebra diolocata 3 1 4 Ogyrides alphaerostris I I Sinmina op. I I Opatipes ocellatua 2 1 3 Triphora nigrocincta 1 1 Pagurus longicarpus 10 20 7 5 42 Uroaalpinx cinerea I 1 Palaemonetea op. 68 51 23 13 155 CEPHALOPODA Panopeue herbatii 7 9 4 4 24 Lolliguncula brevis 12 56 37 24 129 Penaeus astecuo 14 11 1 26 COBLENTERATA Planaeus cluorarwn 3 12 4 4 23 Antbozoa I I Table 52. (continued) Number Collected Organism Winter Spring Summmer Fall @. -ij CUUENTEPLATA (cmt'd) I., , :@ ht. 11", 5 19 17 1 42 Itydrowdumae 21 14 4 39 2 2 -4uzit;u" I wl'tat" 14 12 5 1 32 hwurid I I ,@,,nilla 1 2 3 CTENOPHDRA Ctemphora sp. 13 18 2 8 41 ANKELIDA AoWham: t c a,!@ t 2 2 CCm,I,mt;,I-7 lu'l, -.e 2 Glvccrida@ 4 2 scmi@ P. I Hirudenia 6 3 9 Nicvl@ i. r 9 2 5 2 18 Terebellidw 1 1 2 CHAETOGRATA Swj: t ta e 1. ,an- 2 ECHIIIDDERMATA Ec;zinaraoizri@ 2 3 'j,hioderwU i-r@zlia: "nia I I Schlerodwt-,Ia briay@ 2 5 1 8 PLANT MATERIAL bl,@rti,w alt"miflom 28 16 4 4 52 Ulva laet-, 7 5 1 13 PORIFERA Haliclona o,ulata 4 4 3 3 14 Poriferm I I UROCHORDATA M@lgula ap. 5 3 3 3 14 Peraphora oiridio 3 4 7 BRYOZOA Anquinella palmtu to 6 1 17 ILEPTIUA Alalaolcmye termpin tcr"21,@n I Table 53. occurrence of organisms collected by trawling by sector in the coastal waters of Glynn County, Georgia from January 1979 through June 1980. Number Collected Number Ct,11-ted Organism Creek Sound Beach Total Organism Creek Sound Beach T,,tal PISCES barimus fasciatue I b 7 Anchoa hepsetua 4 2 5 11 Leiostomuo xanthurus 27 16 13 5b Anchoa m@tchilli 98 91 77 266 Menidia menidia 8 2 6 16 Ancylopsetta [email protected]'ata 6 3 3 12 Menticirrhus mwricanus to 15 16 41 Angruilla roetrata 3 7 4 14 Menticirrhus littoralis I I Arius felis 3 5 11 19 #icy-opogoniae undulatuo 70 58 60 188 Astroscopue y-graecwa 2 4 6 Monaca@thue hispidus 1 3 1 5 Bagre marinus 2 a 10 Alugil cephalus 2 1 3 Bairdiella chryaoura 13 15 5 33 ophichthuo ophie 3 2 3 a Bmwortia tyytumus I a 9 18 Ophidion marginatwn 2 19 21 Cw@a. hippoa ' I I Opsanus tau 1 2 3 Centropristia phila&Zphica 1 1 2 Paratichthys dentatue 3 1 4 Chaetodipterus faber 3 7 3 13 Pamlichthys lethostigma I I Chilomycteruo achoepfi I 1 1 3 FapriZus alepidotue 1 2 3 Chloposcomby-a ch-.ymo%B 2 6 3 11 pomtMW aaztatr-@x 1 .2 1 4 Citharichthys epilopterza 1 1 2 Prionotus evolana 1 3 4 Cywacion nothus 4 5 9 Prionotus op. 10 16 16 42 Cywscion Mgazis 34 23 21 78 Sciae-ions oceltatus I I Mpe saurus 3 4 5 12 seophthaZms aquosus 1 2 3 stropua CrOeBotua 13 10 3 26 SeZene oomer 4 3 2 9 Nucinostome guta I I Sphy- gu-h--ho I I Fundulue hetemcZitu8 2 2 StelZifer lanceolatus 13 19 32 64 ^obioidea browasoneti 8 3 1 12 3.4mipiturus plagiusa 36 31 23 90 Cobiosom boaci I I Syngnathidae 4 6 7 17 HMp*obZemiue hentai I I Synodus f-t- I I .[@tazurue catus 1 1 2 Trachinotus carolinus 2 2 LagocephaZua laevigatua 7 4 a 19 Trinectee maculatus 4 4 15 23 Lagodon rhomboides I I Urophycis regia 1 2 1 4 Table 53. (continued) Number Collected Number Collected Organism Creek Sound Beach Total (Yrganism Creek Sound Beach Total ARTFMOPODA Penaeus setiferus 54 48 32 134 Acetes wner:,-anus 23 46 42 111 Portunus gibbesii I I Alpheus heterochelia 11 7 3 21 Pycnogonida 2 1 3 Amphipoda 2 2 Seearma reticulatwn I I Anthuridae 6 2 1 9 Sicyonia so. 1 1 2 Arenaeu8 cribrarius 1 1 Squilla empusa 6 6 10 22 Callinectes 8apidus 38 32 27 97 Trachypeneus constrictus 34 -33 51 118 Cawer irmratuo 1 2 1 4 Uca pugi@ator 2 2 Corapue tubularius 1 1 MEROSTOMATA Chthapmalus fragitis I I Limutus polyohemus 1 1 Copepoda 8 7 6 21 HOLLUSCA O@on septemspinosa I I Anachis avara 1 1 Ga"rxuw mucronatus 1 2 1 4 Busycon canaliculaturn 2 2 Hepatuo epheliticus 17 16 26 59 Cmssotrea virginica 5 2 1 8 Hexapanopeus angustifrone 1 1 Eupleura caudata I I Hippolyomta wurdem=ni 1 5. 4 10 Mercenaria mercenar-@a 6 1 3 10 idotea op. I I Modiolua demissus 2 2 loo ,poda 45 57 56 158 Naaaariua obsoletus I I Libinia emmVinata 5 2 7 Naosarius vibex 35 14 10 59 Menippe mercenaria 1 5 6 4udibranchia 2 2 1 5 Mysidae 48 50 30 128 Terebra dislocata 4 4 Ogyrides alphaer-oatris I I Simina op. I Ovalipea ocellatue 3 3 Triphora nigrocincta I I PaZaemontes op. 75 5b 22 155 Urosalpinx cinerea I I Panopeus herbatii 10 10 4 24 CEPHALDPODA Pdrgurua longicar-pus 4 13 25 42 Lolliguncula brevis 38 40 51 129 Penaeus, astecue Is 11 26 COELENTERATA Penaeue duorarwyi 11 6 6 23 Anthozoa I Tabl.- 53. (continued) Nuvib.r C.11-ted Organim Cr-k Sound B-ch Tot. I llyd,,,--d...,- 11 13 18 42 "I t,2 2 2 Naw;it;l -C I U-t,t. 6 13 13 32 1 2 3 CTENOPHORA Cronophora sl,. 14 1 h it 41 ANNELIDA Amph@mto ., -a.,"[email protected] 1 1 2 C,@bmtuzu.- 1 ; .-U.. 2 2 Piolwt@. m.@ I I Gly,- tdae 4 1 1 6 HIr.dcnf. 3 2 4 9 N. :"x 7 7 4 18 CD rerebellid., 1 1 2 CHAETOC.XATRA .7agitt, 2 1 3 ECHIW)DERMATA E,-hin-z,[email protected] 1@-z 3 3 1 7 8 PLANT MATERIAL :@,art@ml a7t@lml: - -, 12 12 52 z 28 Ul"a Z.Ctz,ca 6 3 4 13 PORIFERA 11aliclona culat,x 2 7 5 14 P-Ifer. I UROCHORDATA molqula op. 8 6 14 Pu@phora viridiv 2 5 7 BRYOZOA Angui@Lla palmta 4 8 5 17 REPTILTA MaZaclepmjs termpin termipin 3 3 Table 54. The 15 most commonly occurring organisms belonging to the classes Pisces and Crustacea collected in 216 samples made with a three-meter trawl. Pisces Crustacea organism Number Collected Or Mer Collect= ganism, Num Anchoa mitchilli 266 Isopoda 158 Micropogonias undulatus 188 Palaemonetes sp. 155 Symphurus plagiusa 90 Penaeus setiferus 134 Cywcion regalia 78 Mysidae 128 Stellifer lmweolatus 64 Trachypeneus constrictus 118 Leiostonw xanthurus 56 Acetes onericanus ill Pri-onotus ep. 42 CalZinectes sapidus 87 0 Menticirrhus, americanus 41 Hepatus opheliticus 59 BairdieZZa chryaoura 33 Pagurus longicarpus 42 Etropus crossotue 26 Penaeus aztecus 26 Trinectes maculatus 23 Panopeus herbatii 24 Ophidion marginatwn 21 Penaeus duorarum 23 Arius felis 19 Squilla empusa 22 Lagocephalus laevigatus 19 Alpheus heterochelis 21 Brevoortia tyrannue 18 Copepoda 21 with available food items determined from trawl samples were limited. WEAKFISH Weakfish (Cynoscion regalis) range from west-central to south Florida in the Gulf of Mexico and along the Altantic coast from south Florida to Nova Scotia (Fischer, 1978). Weakfish prefer habitats very similar to that of spotted seatrout. However, they are generally,found in deeper waters within the estuarine systems. As opposed to spotted seatrout, most larger weakfish move offshore during the colder months, but juveniles may remain in Georgia estuaries year-round. Movement and Migration From February 7, 1979 through June 28, 1982, 2,958 weakfish were tagged and released. Length frequencies of tagged weakfish in 50 mm length groups are included in Table 55. Lengths (TL) of weakfish tagged with Howitt tags ranged from 118 to 475 mm, and with Floy tags from 103- 440 mm. Length frequencies of weakfish tagged with each tag type are shown in Table 56. Table 57 lists the length frequencies of weakfish collected for tagging in 20 mm groups by gear type. Tagged weakfish were returned from October 31, 1979 through March 15, 1982. Of the 2,958 weakfish tagged, 48 (1.6%) were recaptured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged as high as 8.9%. Information on the number of fish released and recaptured, time at large, and distance traveled are shown in.Table 55. The time at large for weakfish ranged from I to 367 days, averaging 62 days. Distance traveled ranged as far as 167 km with an average of 8.3 km. The overall recovery rate was 2.0% for weakfish tagged with Howitt tags and only 0.2% for fish tagged with-Floy tags (Table 56). However, approximately 77% of the weakfish tagged with Floy tags were smaller than the minimum creel size fish captured by recreational fishermen (Table 12). Recovery rates of tagged weakfish, when separated into 50 mm length groups, ranged as high as 9.5% with Howitt tags and 0.5% 107 Table 55. Number tagged, number and percent recaptured, days at large and distance traveled for weakfish, Cynoacion regalia, in-50 mm length groups. Number Number Percent Days At IArge Distance Traveled (km)-!/ I,ength Group Tagged RecRtured Returned LVA. max. Avg. Max. 101 - 150 231 1 0.4 1 1 0.0 0 151 - 200 1,053 0 0.0 201 - 250 750 3 0.4 153 367 15.4 39 200 3 1.4 70 79 31.5 80 C-1 251 - 300 301 - 350 364 12 3.3 103 299 3.2 24 351 - 400 298 25 8.4 38 335 8.7 167 401 - 450 45 4. 8.9 24 43 0.0 0 451 - 500 8 0 0.0 Total 2,958 48 1.6 62 367 8.3 167 l/ Distance measured in kilometers from point of release to point of recapture. O'I (I (I ti a a 0 9 0 Table 56. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for weakfish, Cynoscion regaZis, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numbir Number Percent (MM) Tagged Returned RecUtured Tagged Returned Recaptured Tagged Returned Recaptured 125 25 206 1 0.5 231 1 0.4 175 787 266 1,053 225 664 3 0.5 86 750 3 0.4 .275 185 3 1.6 24 209 3 1.4 325 347 12 3.5 17 364 12 3.3 375 286 25 8.7 12 298 25 8.4 425 42 4 9.5 3 45 4 8.9 475 8 8 Total 2,344 47 2.0 614 1 0.2 2,958 48 1.6 Table 57. Number of weakf ish, Cynoscion regalia, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Gill Net (in).:Y Trammel Length Gr2!RLAmm) 2 2-7/8 3-1/2 4-5/@ Net Seine Trawl Totals 110 - - - 10 10 130 - - 122 122 150 1 1 - - - - 241 243 170 11 - - - - - 359 370 190 2 - - - - - 537 539 210 - - - - - - 449 449 230 1 1 - - - - 229 231 250 1 2 - - I - 122 126 270 - 2 - - 2 - 84 88 290 3 14 - - - - 48 65 310 5 54 - - 5 - 27 91 330 3 141 - 1 8 - 13 166 350 2 180 - 1 17 - 5 205 370 1 118 1 2 12 1 - 135 390 - 52 - 4 7 - 2 65 410 - 24 1 4 1 - 30 430 - 7 - 3 2 - 12 450 - 4 - - - 4 470 - 7 - - - - - 7 Totals 30 607 2 15 55 1 2248 2958 -!/Gill net sizes are stretch mesh measurements. (I ti with Floy tags. Similar contrasting tag retention qualities were observed with release-recapture of spotted seatrout (Table 8). Recreational fishermen accounted for 17 (35.4%) of the 48 recoveries. Seven (14.6%) returns were from commercial shrimp fishermen, and 24 (50.0%) were obtained through study activities (Table 11). Of the 17 recreational recaptures, only 11 (65%) included sufficient information to determine lengths of creel size fish. Lengths of recreational re- captures ranged from 205 to 392 mm with an average size of 326 mm (Table 12). Length frequencies of recaptured weakfish indicated that most creel size fish (54.5%) ranged from 350 to 500 mm (Table 13). Approximately 43% of all weakfish tagged were smaller than the minimum length of any creel size fish recaptured by recreational fishermen. Sufficient recapture information was obtained to determine the estuarine sector location and season of capture for all recaptured weak- fish. The sounds produced 75.0% of the recoveries (Table 14). However, the higher return rate from this area was apparently the result of the higher number of weakfish (90.4%) released in the sounds. Creek, beach, and offshore sectors produced 6 (12.5%), 2 (4.2%), and 4 (8.3%) recoveries, respectively. Although recovery information was limited, data indicate most recoveries (77.8%) were taken in the sounds during the fall. Weak- fish do occur in the upper creeks in the fall but move to areas with higher salinities in the winter (Table 15). All weakfish recaptured by recreational fishermen were caught by Georgia residents in Georgia waters. Most fishermen (76%) traveled less than 40 km to reach the location of fish recapture (Table 16). The principal bait used by recreational fishermen to catch weakfish was shrimp (86%), and the number of recoveries caught with live or dead shrimp was equal (Table 17). Artificial lures and cut bait accounted for the remainder. Approximately 67% of weakfish recoveries were caught in the imme- diate area of release. This percentage is greater.than observed for spotted seatrout (49.2%), but the average at large time for spotted seatrout was approximately five months longer (Tables 7 and 55). Of the 46 weakfish recoveries with sufficient information to ascertain movement, 43 (93.5%) were recaptured within 25 km of the release site (Table 58). However, recovery information was insufficient to deter- mine seasonal movement within the estuary (Table 59). Recovery data indicate weakfish 200 to 300 mm generally exhibit greater movement than larger individuals (Table 55). Although one 362 mm weakfish traveled the greatest distance (167 km), the remaining individuals (24) in this length group (351-400 mm) averaged only 2.3 km. Only one weakfish migrated out of Georgia waters. This individual was tagged in St. Simons Sound and recaptured 43 days later in Matanzas Inlet, Florida by a commercial shrimper, a distance of 167 km. Migra- tion was generally to offshore waters during spawning and cold water months. Recovery data were insufficient to document if weakfish return to their original estuary. Only three weakfish traveled more than 25 km before recapture, thus limiting movement analyses. Two of the three migrated southward and were recaptured during November. The third individual migrated northward and was recaptured during April. Although recovery information was insufficient to document exten- sive movements of Georgia weakfish, migration of weakfish on the Atlantic coast of the United States was previously reported by Wilk (1979). He reported that young individuals, less than four years old, migrated southward below Cape Hatteras as far as Florida in fall and winter and northward in spring and summer. Individuals over four years old migrated southward as far as North Carolina in the fall and returned to their northern estuaries in spring. Although weakfish. over three years old do occur in Georgia estuaries, recovery information was in- sufficient to ascertain their movements. Beaumariage (1969) tagged nine weakfish and only three were recovered. No movement or growth was observed for these three specimens. Length-Weight Relationship Length and weight measurements were collected for 327 weakfisb ranging from 92 to 564 mm and 15 to 2,319 g, respectively. The 112 with Floy tags. Similar contrasting tag retention qualities were observed with release-recapture of spotted seatrout (Table 8). Recreational fishermen accounted for 17 (35.4%) of the 48 recoveries. Seven (14.6%) returns were from commercial shrimp fishermen, and 24 (50.0%) were obtained through study activities (Table 11). Of the 17 recreational recaptures, only 11 (65%) included sufficient information to determine lengths of creel size fish. Lengths of recreational re- captures ranged from 205 to 392 mm with an average size of 326 mm (Table 12). Length frequencies of recaptured weakfish indicated that most creel size fish (54.5%) ranged from 350 to 500 mm (Table 13). Approximately 43% of all weakfish tagged were smaller than the minimum length of any creel size fish recaptured by recreational fishermen. Sufficient recapture information was obtained to determine the estuarine sector location and season of capture for all recaptured weak- fish. The sounds produced 75.0% of the recoveries (Table 14). However, the higher return rate from this area was apparently the result of the higher number of weakfish (90.4%) released in the sounds. Creek, beach, and offshore sectors produced 6 (12.5%), 2 (4.2%), and 4 (8.3%) recoveries, respectively. Although recovery information was limited, data indicate most recoveries (77.8%) were taken in the sounds during the fall. Weak- fish do occur in the upper creeks in the fall but move to areas with higher salinities in the winter (Table 15). All weakfish recaptured by recreational fishermen were caught by Georgia residents in Georgia waters. Most fishermen (76%) traveled less than 40 km to reach the location of fish recapture (Table 16). The principal bait used by recreational fishermen to catch weakfish was shrimp (86%), and the number of recoveries caught with live or dead shrimp was equal (Table 17), Artificial lures and cut bait accounted for the remainder. Approximately 67% of weakfish recoveries were caught in the imme- diate area of release. This percentage is greater than observed for spotted seatrout (49.2%), but the average at large time for spotted seatrout was approximately five months longer (Tables 7 and 55). Of the 46 weakfish recoveries with sufficient information to ascertain movement, 43 (93.5%) were recaptured within 25 km of the release site (Table 58). However, recovery information was insufficient to deter- mine seasonal movement within the estuary (Table 59). Recovery data indicate weakfish 200 to 300 mm generally exhibit greater movement than larger individuals (Table 55). Although one 362 mm weakfish traveled the greatest distance (167 km), the remaining individuals (24) in this length group (351-400 mm) averaged only 2.3 km. Only one weakfish migrated out of Georgia waters. This individual was tagged in St. Simons Sound and recaptured 43 days later in Matanzas Inlet, Florida by a commercial shrimper, a distance of 167 km. Migra- tion was generally to offshore waters during spawning and cold water months. Recovery data were insufficient to document if weakfish return to their original estuary. Only three weakfish traveled more than 25 km before recapture, thus limiting movement analyses. Two of the three migrated southward and were recaptured during November. The third individual migrated northward and was recaptured during April. Although recovery informat ion was insufficient to document exten- sive movements of Georgia weakfish, migration of weakfish on the Atlantic coast of the United States was previously reported by Wilk (1979). He reported that young individuals, less than four years old, migrated southward below Cape Hatteras as far as Florida in fall and winter and northward in spring and summer. Individuals over four years old migrated southward as far as North Carolina in the fall and returned to their northern estuaries in spring. Although weakfish. over three years old do occur in Georgia estuaries, recovery information was in- sufficient to ascertain their movements. Beaumariage (1969) tagged nine weakfish and only three were recovered. No movement or growth was observed for these three specimens. Length-Weight Relationship Length and weight measurements were collected for 327 weakfish ranging from 92 to 564 mm and 15 to 2,319 g, respectively. The 112 with Floy tags. Similar contrasting tag retention qualities were observed with release-recapture of spotted seatrout (Table 8). Recreational fishermen accounted for 17 (35.4%) of the 48 recoveries. Seven (14.6%) returns were from commercial shrimp fishermen, and 24 (50.0%) were obtained through study activities (Table 11). Of the 17 recreational recaptures, only 11 (65%) included sufficient information to determine lengths of creel size fish. Lengths of recreational re- captures ranged from 205 to 392 mm with an average size of 326 mm (Table 12). Length frequencies of recaptured weakfish indicated that most creel size fish (54.5%) ranged from 350 to 500 mm (Table 13). Approximately 43% of all weakfish tagged were smaller than the minimum length of any creel size fish recaptured by recreational fishermen. Sufficient recapture information was obtained to determine the estuarine sector location and season of capture for all recaptured weak- fish. The sounds produced 75.0% of the recoveries (Table 14). However, the higher return rate from this area was apparently the result of the higher number of weakfish (90.4%) released in the sounds. Creek, beach, and offshore sectors produced 6 (12.5%), 2 (4.2%), and 4 (8.3%) recoveries, respectively. Although recovery information was limited, data indicate most recoveries (77.8%) were taken in the sounds during the fall. Weak- fish do occur in the upper creeks in the fall but move to areas with higher salinities in the winter (Table 15). All weakfish recaptured by recreational fishermen were caught by Georgia residents in Georgia waters. Most fishermen (76%) traveled less than 40 km to reach the location of fish recapture (Table 16). The principal bait used by recreational fishermen to catch weakfish was shrimp (86%), and the number of recoveries caught with live or dead shrimp was equal (Table 17). Artificial lures and cut bait accounted for the remainder. Approximately 67% of weakfish recoveries were caught in the imme- diate area of release. This percentage is greater than observed for spotted seatrout (49.2%), but the average at large time for spotted seatrout was approximately five months longer (Tables 7 and 55). Of 10 the 46 weakfish recoveries with sufficient information to ascertain movement, 43 (93.5%) were recaptured within 25 km of the release site (Table 58). However, recovery information was insufficient to deter- mine seasonal movement within the estuary (Table 59). Recovery data indicate weakfish 200 to 300 mm generally exhibit greater movement than larger individuals (Table 55). Although one 362 mm weakfish traveled the greatest distance (167 km), the remaining individuals (24) in this length group (351-400 mm) averaged only 2.3 km. Only one weakfish migrated out of Georgia waters. This individual was tagged in St. Simons Sound and recaptured 43 days later in Matanzas Inlet, Florida by a commercial shrimper, a distance of 167 km. Migra- tion was generally to offshore waters during spawning and cold water months. Recovery data were insufficient to document if weakfish return to their original estuary. Only three weakfish traveled more than 25 km before recapture, thus limiting movement analyses. Two of the three migrated southward and were recaptured during November. The third individual migrated northward and was recaptured during April. Although recovery information was insufficient to document exten- sive movements of Georgia weakfish, migration of weakfish on the Atlantic coast of the United States was previously reported by Wilk (1979). He reported that young individuals, less than four years old, migrated southward below Cape Hatteras as far as Florida in fall and winter and northward in spring and summer. Individuals over four years old migrated southward as far as North Carolina in the fall and returned to their northern estuaries in spring. Although weakfish. over three years old do occur in Georgia estuaries, recovery information was in- sufficient to ascertain their movements. Beaumariage (1969) tagged nine weakfish and only three were recovered. No movement or growth was observed for these three specimens. Length-Weight Relationship Length and weight measurements were collected for 327 weakfisb ranging from 92 to 564 mm and 15 to 2,319 g, respectively. The 112 Table 58. Days at large and distance traveled for weakfish, Cynoscion regalis, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At - Distance Traveled (km) Large 0 0.1-1 1-5 6-25 26-50 51-100 101-200 Total Percent 1 - 50 19 1 2 5 1 - 1 29 63.0 51 - 100 6 - - 2 - 1 - 9 19.6 101 - 150 1 - - - 1 2.2 151 - 200 4 - 4 8.7 20-1 - 300 1 1 - 2 4.3 301 - 500 - 1 - - - - 1 2.2 Total 31 2 2 8 1 1 1 46 100.0 Percent 67.4 4.3 4.3 17.4 2.2 2.2 2.2 100.0 NOTE: Only 46 of the 48 recaptures had sufficient information to calculate distance traveled. Table 59. Seasonal movement of weakfish, C@nosciun tagged In the coastal waters of GlY1111 Colliltv. Georgia from January 1979 through June 1982. -FAtqght In Area Direction Moved By Recaptured Tamed Fish Moue" t Out Of Estuary Length Group movement With Season (010) Of Release Crea to ww@%Nwlcreek North South Winter 201-250 251-300 - 301-350 1 1 - - I 351-400 - I - - 1 401-450 - - - - - Total 1 2 - - 2 Percent 20.0 40.0 - - 40.0 Spring 201-250 - I - - - 251-300 - - I 301-350 4 351-400 - 401-450 - - 4- Total 4 1 1 Percent 66.6 16.7 16.7 Summer 201-250 - - - 251-300 - 301-350 2 351-400 - 401-450 Total Percent 100.0 - Fail 201-250 - 2 251-300 - - I - 301-350 7 - - 1 351-400 14 - 2 1 2 401-450 3 - - - - Total 24 - 3 3 3 Percent 72.7 - 9.1 9.1 9.1 Combined Total 31 3 3 4 5 Percent 67.4 6.5 6.5 8.7 10.9 length-weight relationship equations for males, females, and combined sexes are shown in Table 24. Figure 22 illustrates the length-weight relationships for weakfish. The length-weight relationships calculated showed isometric growth (b = 2.920). The greatest lengths recorded for male and female weakfish were 397 and 564 mm, respectively. The heaviest weakfish weighed 640 g for males and 2,319 g for females. Wilk (1980) presented length-weight equations for weakfish collected in the New York Bight. Weights were similar to those for Georgia fish of equal length. There also appears to be little difference between male and female length-weight relationships. Age and Growth The scale technique for ageing weakfish has been validated as an ageing method by Welsh and Breder (1924), Massmann (1963) and Wilk (1979). Scale annuli marks were described by Massmann (1963) as: 1) cutting over of circuli which are most apparent in the lateral field; 2) crowding to- gether of circuli in the anterior portion of the scale; and 3) the appear- ance of secondary radii originating at zones where circuli are crowded together. Scale samples from 311 weakfish ranging from 77 to 564 mm were ex- amined, and 243 (78%) were determined usable for age analyses. Otolith sections of these 243 fish were also examined to document the validity of annuli counts made from scales. Year-mark formation on weakfish scales and otolitbs are similar to that observed for spotted seatrout. Considering the scale-otolith year mark difference as observed for spotted seatrout, scales and otoliths examined from the same weakfish exhibited 95.9% agreement in age. Calculation of mean monthly growth of marginal increments vali- dated that scale annuli are formed only once annually. A single annulus formation was detectable on most weakfish scales from late March through June with all scales bearing recent annuli by early July. Least-squares regression analyses were performed on the relation- ship between fish length and scale radius. The r 2 value of 0.82 115 4.8-- W= .000017 L2-920 4.2-- n= 327 r2= .95 3.6-- C-D 3 2.4-- C.D LU 0.6-- 10 20 30 40 50 70 80 TOTAL LENGTH (CM) Figure 22. Length-weigth relationship of weakfish, cynoscion regaZis, collected in Glynn County, Georgia from January 1979 through June 1982. 116 (P < 0.0001) suggests the relationship was sufficiently linear to warrant direct proportion calculations to determine fish lengths at time of annulus formation. The empirical and mean back-calculated total lengths of weakfish by age are shown in Table 60. Figure 23 illustrates the length-age relationship for weakfish, and length-age equations are included in Table 27. Table 61 shows the empirical and weighted-mean back-calculated lengths for juveniles, males, females, and combined weakfish. To document the annual growth rate of weakfish, the mean growth for all weakfish at large from 11 to 13 months were calculated. Un- fortunately, recapture lengths were obtained for only two weakfish at large for approximately one year. One specimen measured 228 mm when released and had grown 64 mm, and the other originally measured 397 mm and had grown only 13 mm. Thus, sufficient recapture information was not available to document growth rates derived from back-calculations. The oldest weakfish collected during this study were an age VII female and an age IV male. Maximum ages for combined weakfish in Georgia are similar to ages reported by Welsh and Breder (1924), Massmann (1963), and Wilk (1979). Mean back-calculated lengths for Georgia weakfish under six years of age are similar to the findings of several studies as reported by Wilk (1979). However, Georgia weak- fish are generally smaller at age than fish from the more northern waters. Maturity and Spawning Sex differentiation through gross examination was first observed at 146 mm (age 0) for females and 165 mm (age 0) for males. The smallest female exhibiting developing ovaries (stage III or greater) was a 275 mm (age II) specimen. The smallest male exhibiting develop- ing maturitywas a370 mm (age III) specimen. Gear selectivity may have biased the collection of males toward larger specimens. Wilk (1973) reported that weakfish are sexually mature for the first time in their second year of life. Merriner (1976) reported 117 01 Table 60. Mean back-calculated total lengths for weakf ish, Cynoscion regalia, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Length Range Mean Length Lengths of Successive Scale Rings Age Number at Capture at Capture 1 2 3 4 5 6 7 0 23 77 217 151 1 42 140 327 213 144 2 84 205 386 316 172 266 3 82 267 459 363 158 260 327 4 9 345 438 395 166 273 333 374 5 2 401 505 453 193 298 355 393 439 6 0 7 1 564 564 217 288 357 403 457 500 544 Weighted Means 162 264 329 380 445 500 544 Growth Increments 162 102 65 51 65 55 44 NOTE: Lengths measured in millimeters. ft d1k 70 A= .000248 L 1 625 2 n= 328 r 67 60 50 z _j 40 0 30 20 10 1 2 3 4 5 6 7 AGE (YEAR) Figure 23. Length-age relationship of weakfish, Cynoscion regazis, collected i;i Glynn County, Georgia. 119 go Table 61. Number, empirical and back-calculated total lengths and growth increments by sex and age for weakfish, Cynoscion regalis, collected in coastal waters of Glvnn Count% Georgia from January 1979 through June 1982. e Sex 1 2 3 4 5 6 7 Juveniles Number 4 1 Mean Length at Capture 159 259 Back-Calculated Length 120 208 Growth Increment 120 88 Males Number 13 14 7 2 Mean Length at Capture 195 279 333 371 Back-Calculated Length 151 251 309 348 Growth Increment 151 100 58 39 Females Number 25 69 75 7 2 0 1 Mean Length at Capture 231 325 365 402 453 564 Back-Calculated Length 166 266 331 386 445 '500 544 Growth Increment 166 100 65 55 59 55 44 Combined Number 42 84 82 9 2 0 1 Mean Length at Capture 213 316 363 395 453 564 Back-Calculated Length 162 264 329 380 445' 500 544 Growth Increment 162 102 65 51 65 55 44 NOTE: Lengths measured in millimeters. 41 41 0 a a a that both females and males become sexually mature at age I with a few maturing at age II in North Carolina waters. Wilk (1979) reported that most, if not all, weakfish are sexually mature by age II. Georgia weakfish have a protracted spawning season extending from March through September. The stages of gonadal development for female and male weakfish are presented by month in Table 62. Only 16 female weakfish exhibiting advanced stages of ovarian development were collected and these came from the inside waters from the beaches inward. Of all females collected during March, 12.5% exhibited advanced ovarian develop- ment. Spawning activity apparently peaked in April when 29.4% of the females exhibited advanced development. The percentage dropped sharply to 13.3% in May and 10.3% in June. No advanced development was observed in July and August, but two prespawn females (stage V) were collected in September. Very early postlarval and yolk stage weakfish were collected in ichthyoplankton samples from the beach in May (Table 63). Unfortunately, laboratory identification of plankton samples were contracted only for the initial 5-month period of January through May. No young weakfish were collected in the 3 meter trawl samples during winter, but their numbers increased sharply in spring, peaked in summer and then sharply declined again in fall (Table 52). Although young specimens were distri- buted throughout the estuaries, there was an increase in occurrence from the beaches to the creeks (Table 53). There was near equal occurrence of young in the sounds and on the beaches, but there was approximately a 30% higher occurrence rate in the creeks. The reproductive stages for female and male weakfish by month and salinity appear in Table 64. No advanced stages of ovarian development were observed from salinities <15 0/oo. Advanced ovarian development was observed at salinities above 16 0/oo but females in spawning con- dition were found only in salinities above 26 0/oo, indicating that most weakfish spawning activity takes place in the high salinity waters near the beaches and open ocean. Georgia's sounds are relatively small and little effort would have to be exerted for prespawners to move to 121 Table 62. Number of weakfish, Cynoscion regaZis, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage I II III IV V VI VII Month F M F F M F M F -M R F M January 16 1 9 0 1 0 February 2 0 28 0 0 0 March a 3 19 2 7 0 2 1 2 0 April 0 2 4 1 8 0 2 0 3 0 May 4 1 7 0 2 0 1 0 1 0 June 4 4 is 0 7 0 3 0 July 9 10 6 0 1 0 Auguat 1 0 2 0 September 20 5 2 0 1 0 2 0 October 7 2 5 0 2 0 November 16 1 6 0 1 0 December 9 10 13 0 1 0 Table 63. Ichthyoplanktos @Ilect*d by mooth In Glym County, Geoygi& ftne, January 1979 through May 1919. Jammly F*broar'T Awles Creeks sounds beaches fo-tal -Cretk.Sounft Beach" T@t-al Creeks Sounds Total Imiostommor *Mthkrw 13-PIA' 9-PI 5-FL 27-PI 27-Pl 27-PI MCO-POO-i- I-PI IOWA" - - - - - 4-PI 4-PI Goblidam - - - - - sciagaide. Ahvil or. I-PI I-Pi Mmidia 1-7- 2/ 5-Y.; 17-PI 2-PI &-y.; 21-PI maxidia 3-Ad- 3/ _ 3-Ad 3-Ad 4-Ad 7-Ad 3-PI 2-Ad Z-Ad 4-Ad LaPP&M Axmbo,ijas 5-pi 2-TI - 7-Pi 3-71 b-PI - 14-PI 2-Pi I-Pi - 3-pi 1'' 2-jv 5_j@ I-,jv I-J@ witakiiii I-Ad I-Ad Z-Ad t_j 4/ 3-j@ I-Ad I-Ad I-Ad I-Ad 2-t. ],_IA pid'em's I-PI - I-PI 3-71 I-PI 4-pi AFevoortia op. - 19-pi 1"I "1 29 Pi 2-PI 40-PI magresAwma, claymmid" BIENNIUM,* SymgmetbLdem 44-r-idem ap. Amohoa hapsatum 41"Oddio" Ab"Domthme hispidwe AhAntioirMus op. p1mmawtas op. h4mactse Affiamiatme Prionotim op. jjF1 - Postlerval !/To Tolkstage !/Ad Adult A/jv juvemille Leptocephalm Table 63. (continued) April Mwv Speclem Creeks Sounds beaches __ Total Creeks Sounds Beaches Total- Loi4v tomm xamth@ 101&zatus motbidam Goblid" 4-FL 4-PI - A-pi 50-Pi 1-Y.; 2/ 5-Pi (_PI 1-Y.; 61-PI Sciammidas I-To; 4-PL 7-Pi - I-Y.; It-PI I-Pi - I-Pi Mwvil op. 2-PI - 2-Pl Ahatidia I-To I-To 2-yo I-Ys; 29-PI S-Ys; 23-PI 9-Y.; 55-Pl Ampti&A 3"1 152-Pi 9_1PI IwrI I-J@ I-jv 3_PI Z-Jv Laradam rhomboides 4-PI 4-PI I-ri - I-Pi Awhoa 174-PI 21-PI 43-PI 238-Fl. I-Jv mitakiiii I-Ad' 3-Ad I-iv 4-Ad 11-Ad 15-Ad Arspaphis pwootatum, Places 4-To 4-Ya 8-ya I-PI 3-Pt 4-PI Rrevoo@tia op. 7-PI 7-PI bmwmlldm 4-PI wri I-PI 25-PI 2327-PI I-To. S4-PI 120-PI I-To; 2501-PI C"paid" I_rI 40-PI 4-PI 4"1 - stemild" 4-Yo; 4-PI - - 4-Ts; 4-PI - I-pi I_?I OyaWathidiss - I-Jv; I-Ad I-Jv; L-Ad - 2PI; 2,Jv - 2-PI; 2-JV (4- up- - 2_jv 2-JV I-Pi I-iv I-Jv 2-Jv. I-PI Awhoa 7-pi 91-Pi hopeet" I_jv 15-Pi 69-Pl I-J. 10-Ye 10-TS C@ftofoi_ - 16-PI 16-PI rovalie Abnoo=thw - I-iv I_jv - I-Ad I-Ad ywkjutw op. - I-ya 1-Ya 2-ri 2-Pi maculatue plp@motmv op. I-Pi I-Pi VIPL - Pontlarval Ya Tolk stage YA&4dult Jv Juvenile !/I* Leptocephalus 'fable 64. Stages of gonadal development for weakfish, Cynoscion regalis, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Salinity (0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 Total* r4,11th Stage F M F H T-N N F M r M -F-M -F M P F January 1 13 1 3 o lb I 11 5 0 4 0 9 III 1 0 1 U IV-VII - - February 1 .2 0 2 0 11 6 0 1 0 21 0 '18 0 III-VII March I 1 0 - - 1 0 0 3 2 3 11 2 0 13 1 1 1 3 0 19 2 III - - b 0 1 0 7 0 IV 2 1 - - :1 1 V 2 0 2 0 VI-VII - - - - rQ 1-n April I - 0 1 0 1 0 2 - - - 1 1 3 0 4 1 1 0 1 0 3 0 2 0 1 0 8 0 IV - - - - 2 0 - - 2 0 V 1 0 1 0 1 0 3 0 V1 4 0 - - 4 0 VII - - - - - - may 1 0 3 1 - - - 4 1 3 0 1 0 3 0 7 0 1 0 1 0 2 0 IV 1 0 1 0 V VI 1 0 1 0 Vil - - June 0 2 4 2 4 4 1 0 14 0 is 0 7 0 7 0 IV - - V 3 0 3 0 VI-VII - - Table 64. (continued) . Surface Water Sallnity_(0/00) Reproductive 0-5 6-10 11-15 16-5- -21-25 - 26-30 31-35 36-40 Totals Stage M M,11t 1k T F F N F M F M F F M F M F M July 0 1 9 9 9 10 1 0 5 0 6 0 1 0 1 0 IV-VII August I 1 0 1 0 11 - - - - - - - 1 0 1 0 2 0 September 1 7 3 1 0 11 2 1 0 20 5 it 1 0 1 0 2 0 III 1 0 1 0 IV - - V 1 0 1 0 2 0 VI-VII October 4 2 2 0 1 0 7 2 5 0 5 0 2 0 2 0 a, November 1 0 13 1 2 0 16 1 5 0 1 0 6 0 1 0 1 0 rV-VII December 8 10 1 0 9 10 9 0 4 0 13 0 1 0 1 0 Combined 1 0 15 5 28 13 30 10 16 11 - - 90 39 Totals it 2 0 27 1 19 1 44 1 24 0 - - 116 3 III 1 0 10 0 7 0 5 0 8 0 - - 31 0 IV 2 1 - - 3 0 5 1 V 4 0 1 0 1 0 4 0 to 0 VI 5 0 5 0 VII ocean waters to spawn. The maturity stages for female and male weakfish are presented by temperature and salinity in Table 65. Gonadal development was first observed when water temperature exceeded 6 0C. However, spawning activity was apparently not fully underway until water temperatures exceeded 16 0C. At salinities below 15 0/oo no ovarian development was observed, but at salinities ranging from 16 to 20 0/oo advanced ovarian development appeared in 10.4% of the females examined. Ripe females (stage VI) were not found until water temperatures exceeded 21 0C and only in salinity above 26 0 /oo. Low numbers of advanced stages of gonadal development made it difficult to determine the precise time and location of spawning. However, most of the adult weakfish collected during this study came from St. Simons Sound near the mouth of Dubignion Creek on the north shore of Jekyll Island. This was the only sampling site to regularly produce larger weakfish in concentrated numbers. This site is less than 0.5 nautical mile from open ocean waters and is readily accessible for rapid movement seaward for spawning in the ocean waters. The number and percent of weakfish showing signs of advanced gonadal development by lunar phase appear in Table 40. Although low numbers of advanced maturity stages were collected, the greatest occurrence was during new moon and last quarter. Of the 20 advanced stages observed, 30% occurred during new moon, 5% during first quarter, 25% during full moon, 30% during last quarter and 10% during split phases. Too few specimens were collected to draw definite conclusions. The sex ratios for weakfish by length group appear in Table 41. The overall ratio of female to male weakfish collected during this study was 6:1. For young weakfish <200 mm the ratio was equal at 1:1 females to males. The ratio increased sharply to 9.5:1 for fish 301-350 Mm and was 47:1 for fish 351-400 mm. No males over 400 mm were collected. Gear selectivity may have accounted for some bias in the collection of males. However, such an extraordinarily high ratio of females to males indicates that there was probably some-natural phenomenon regulating sex segregation within the weakfish population in inside waters. It is 127 Table 65. Stages of gonadal development for weakfish. C@iioroion YwgaU..r;, by water temperature and salinity .gradients for fish collected in Glynn County, Georgia from Janijary 1979 through June 1982. Surface Water Temperature ( 0Q Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-3S TotaN (0/00) Stage F N F N F M F N F M F M I 1 0 11 2 0 .1 0 11-15 111 1 0 1 0 IV-VII I - - 2 0 - - 1 0 5 2 7 3 15 5 11 - - 12 .0 - - 7 1 8 0 - - 27 1 III - - 5 0 - - 1 0 4 0 - - 10 0 16-20 IV - - 0 1 - - 2 0 - - - - 2 1 V 0 2 0 1 0 4 0 VI - - - - - - - Vil - - - - - - I - 22 11 0 1 3 1 3 0 - - 28 1) 11 - 14 1 2 0 1 0 2 0 - - 19 1 III - 2 0 4 1 0 7 0 21-25 IV - - - - V 1 0 1 0 V1 - - VII - - F N) 4 0 13 5 - - 12 5 1 0 30 to Co I - - 11 21 0 8 0 8 0 3 1 3 0 1 0 4 4 1 111 3 0 2 0 5 0 26-30 IV 2 0 - - 2 0 V 1 0 1 0 V1 5 5 0 VII - - - 1 2 0 - - 9 4 5 7 16 11 11 2 0 2 0 2 0 is 0 24 0 III 1 0 7 0 8 0 31-35 IV V 1 0 3 0 4 0 VI VII 1 2 0 27 It 16 6 8 3 31 12 6 7 90 39 11 33 0 22 1 21 1 14 1 7 0 19 0 116 3 111 5 a 2 0 9 0 5 0 3 0 7 0 31 0 TOTALS IV 0 1 - - 4 0 - - - - - - 4 1 V 1 0 - - 3 0 1 0 2 0 3 0 10 0 VI 5 0 - - - - - 5 0 vil - - - - - - - - - OF quite possible that male weakfish prefer a specific salinity range, deeper channels, or remain in offshore waters near shore waiting for females to move seaward to spawn. These theories cannot be validated from this study's data. The number and percentage of female versus male weakfish by salinity level from which they were collected are presented in Table 66. The percentage for all weakfish collected was 86% females and 14% males. There was little difference in the percent occurrence of female and male weakfish at different salinities in inshore waters as males never comprised over 20% at any salinity level. Female weakfish outnumbered males in all months, and comprised over 83% of the catch in all months except July (62%) and December (70%). Fish length-fecundity relationship equations for North Carolina weakfish were reported by Merriner (1976). Using his equation for total length, the estimated fecundity for 350 and 500 mm weakfish were 799,400 and 2,051,100 eggs, respectively. Additional detailed fecundity information is limited for populations from the more southerly waters. As shown in Table 40, very few advanced reproductive stages (stages IV-VII) were collected in the estuarine waters of Glynn County, Georgia. In general, Georgia weakfish spawn in ocean waters beyond the sampling area of this study. Therefore, very few ripe weakfish were collected for fecundity analyses. Fecundity estimates were determined for three weakfish ranging in length, weight, and age from 344 to 373 mm, 450 to 861 g, and III to IV years. Mean estimated fecundity was 151,824 eggs with a range from approximately 115 to 171 thousand. The average total weight of the three specimens was 702 g with the gonads comprising 13% (90.9 g) of the fish weights. Food Preference and Feeding Habits Of the 326 weakfish stomachs analyzed to determine food preferences, 240 (73.6%) contained food and 86 (26.4%) were empty (Table 67). In 129 Table 66. Number and percent of female versus male weakfish. C@Pwooion rogalis. by salinity gradient and month for fish collected In Glynn County, Georgia from January 1979 through June 1982. SURFACE WATER SALINITY (0/00) 0-3 6-10 11-15 16-20 21-25 26-30 31-35 TOTAL MONTH F M F M 7 M F M 7 M F M F M January NO. 19 1 7 0 26 1 2 95 5 100 0 96 4 February No. a 0 1 0 21 0 30 0 % 100 0 100 0 100 0 100 0 Karch NO. 3 0 23 2 3 1 3 3 32 6 2 100 0 92 a 75 25 50 50 94 16 April 50. 1 0 2 0 3 1 10 2 5 0' 21 3 2 100 0 100 0 75 25 83 17 100 0 87 13 may No. 5 0 4 1 6 0 15 1 z 100 0 so 20 100 0 94 6 June NO. 1 2 28 2 29 4 33 67 93 7 as 12 July NO. 2 1 14 9 16 10 % 67 33 61 39 62 38 August NO. 1 0 2 0 3 0 % 100 0 100 0 100 0 September No. a 3 4 0 11 2 2 0 25 5 2 73 27 100 0 '85 15 100 0 83 17 October NO. 11 2 2 0 1 0 14 2 z 65 15 100 0 100 0 87 13 November No. 1 0 19 1 3 0 23 1 z 100 0 95 5 100 0 96 4 December No. is 10 5 0 23 10 2 64 36 100 0 70- 30 TOTALS NO. 4 0 so 7 55 14 as 11 52 11 257 43 z 100 0 11 80 20 89 11 83 17 95 5 Table 67. Stoma.h .-t-t. of makfish, C@-Wa&i@ m9alie, ..11..ted i. Gly- C-ty, G.."t. from J - - - ry 1979 thr-gh J.- 1982. G - (") P.rc..t A--g. Food Item, 201_=th 3;I-p4OO 401-5DO 501-6DO Combi-d Orc-r.- x B.I.. ?ISM Me. (-id-tifible) 1 22 29 49 5 ID6 44.2 70 Awhaa hopvt" I I 0.4 90 Awhod witchiLli 1 4 1 6 2.5 83 Brevoortia tyravow 6 44 1 1 52 21.7 94 chzo",-b@ hyv@ I 1 0.4 40 Lgiostomms @0@ I 1 0.4 90 Mvni,@ft. @ulia I 1 0.4 90 Mrnti@Lrrhus amum@ I 1 0.4 9-0 xenticirrh.8 littorazis I 1 0.4 60 St*Zlifer [email protected] 5 5 1 11 4.6 76 ARTIMOPODA Crastacem (Midentifibl.) 5 3 9 17 7.1 56 Alphew ;@te2w@*Ozio 1 2 3 1.3 57 A.th.rLd- I 1 0.4 90 Cyath@ polit-a 2 2 0.8 90 4.2 69 t- DWAV." 1 4 4 1 10 swobvia Pwri@ 2 8 1 14 25 10.4 57 Ostracod. I 1 0.4 5 FaZomm@etev 2 2 0.8 85 r@id- 1 3 2 6 2.5 55 PwKwus setiferka 7 15 6.3 94 ri"OhNperiems Mutriotus 3 3 1.3 30 CZFSALMMA Caphal.p.d. (.nj4.stjfLbl.) 2 3 1.3 53 LoZZigwwula brw,,ie 1 3 4 1.7 63 AMMIDA Woolen cipz@ I 1 2 0.8 35 FLWT Detrites 3 1 2 6 2.5 spartim altemifZora 3 1 t 5 2.1 54 DDRUNIC RATZRIAL 6 1 7 2.9 82 *Aib.r of sto,earho: 326 lumber and per."t of stow.he contsifti-9 food.- 240 (73.62) r &ad parcaut of empty stomachoS 86 (26.41) weakfish <200 mm there was nearly equal utilization of crustaceans and fish. Mysid shrimp were the dominant crustacean and anchovies (Anchoa mitchilli and Anchoa hepsetus) were the primary fishes utilized as food. In 201-400 mm specimens major food items shifted to menhaden (Brevoortia sp.) as the top fish species,and penaeid shrimp (Penaeus setiferus and Trachypeneus constrictus) and mysid shrimp were the dominant crusta- ceans. For adult weakfish over 400 mm there was approximately equal utilization of menhaden and penaeid shrimp. By far, these two species are of major importance as food for Georgia weakfish. Other investigations along the Atlantic coast observed butterfish, herrings, sand lance, silversides, anchovies, young weakfish, Atlantic croaker, spot, scup and killifish as the most frequently occurring fish as food. Among the invertebrates were assorted shrimp, squids, crabs, annelid worms and clams (Wilk, 1979). Mahood (1974) found the major foods for Georgia weakfish,to be fish (80.6%), shrimp (14.3%), and squid (5.7%). He also found that anchovies dominated the fishes uti- lized by smaller weakfish while menhaden were dominant in larger speci- mens. This is in agreement with our findings presented above. The 10 most frequently occurring food items in weakfish stomachs by season and sector are presented in Table 68. Fish were the most frequently occurring food item in all seasons and all sectors. Menhaden were the most commonly ingested fish, occurring in 21.7% of the stomachs, while mysid shrimp were the most common invertebrate in 10.4%. In the creeks white shrimp (Penaeus setiferus) and star drum (Stellifer lanceolatus) were the dominant food species. In the sounds, the dominant food items were menhaden and mysid shrimp, while on the beaches star drum and mysid shrimp were dominant. The one specimen col- lected from the offshore waters contained only mysid shrimp in its stomach. During winter, mysid shrimp were the most dominant forage species although fish and fish parts were found. The most commonly ingested fish during winter were menhaden and star drum. In spring, fish were the dominant food with menhaden as the dominant species although mysid 132 T.bl. 65. Tb.,!O scot frequantly occurring food itesm, fowW.l 7; the stomachs of wakfish, Clynoec on mgalia. hy sesson and sector for fish col cted in Glym Coonty, Georgia from Jamoory I ,hrough Jove, 1982. winter S.riIs 5- r WD. F-cent A-rage go. Percent A,-S. a.. Percent W---49- Sector Food Itow Sta.-A. ftcurrame. Z Sol- Food Item Stomach. 0-rence Z Sol- Food It- Stomachs 3ccurreoce Sol" Crooks Places 1 200.0 90 Plar, 5 $3.3 78 Place. 2 50.0 50 Alphong op. 1 100.0 10 D-P." 1 16.7 90 A,--hoa mitchilli 1 25 0 cat 1 100.0 .1 A 4,heue op. 1 16'7 70 " Id- 1 25:0 90 C-t-- 1 16.7 20 Pa lae-ne .. op. 1 25.0 go A-lid. 1 25.0 20 Somis rineon 1 31.: 86 ?I__ 24 75.0 ft Brevoortia ty@ 33 48 5 82 Ny.14- 187 29. 95 B-voortia ty-- 4 12.5 90 Places 23 33:8 40 Crow.-te- 9 15.9 71 &-tim alwmif7om 4 12,5 55 Anchoa ait--hilli 5 7.4 82 Vaiduatifled material 5 8.8 9-0 *,*id- 1 9.4 30 Decapd- 5 7.4 74 kwooortia ty@ 3 s 3 90 Plant detr it_ 2 6.3 90 LolligumwniZa bmvis 3 4 4 7 Sulufs, U,,,aoLt.8 3 5:3 93 C-tocas 1 3.1 60 C-tacea 3 4:4 407 2 3.5 60 t1midestified material 1 3.1 40 Pe-euo oetifems 1 1.5 90 A."mus matif.- 1 1-8 90 D-.p.& 1 M 20 P.I.-te. op. 1 1.5 90 I l 90 Cephalopoda 1 3.1 'S My.id- 1 1.5 90 90 Asthu@ridme 1 1.5 90 memebas Pi-- 9 100.0 72 @@ellifer lo-soZat- 1 100.0 100 montioi@A- -ri- 1 11.1 90 C110-l-" 1 11.1 so r-hype- -.trict@ 1 11.1 c5 Offobote y"Idon, 1 100.0 90 AD" - - - 8@- tia ty@ 33 45 2 2 totals Pla." 19 32 2 86 ?1-- 38 so 9 79 Fisee., 25 34:2 481 Ab.Ld- is 30:3 83 [email protected] A 3:5 90 A-46- mi t1ki 12 i 6 8 2 33 Crastat" 9 15.3 71 &p@tim aUemiflom 4 a.5 55 D--P-" 5 6:8 74 Mad material 5 90 Nyolda 3 6 4 30 L.Ilig-1. breio 3 4 1 7 hwvoortia tw@ 3 5:1' 90 Plant detrttoo 2 4:3 10 Crustaces 3 4:1 407 Stdllif" UWk7&0L4t- 3 5.1 93 Detapoda 2 4 3 55 My. id- 2 2 7 90 2 3 A 60 Cph.fopod. 2 4:3 40 PaLacm-et-es op. 2 2:7 85 A op. 2 3:4 so C-tacea 2 4.3 30 Antiturid" 1 1.4 90 Lviwt@ xootth@ 1 1 7 90 mentii-h.8 osmric-e 1 2.1 so P-- -tifeme 1 1.4 90 &.wahuro Polit. l 1:7 90 ALph- op. 1 2.1 70 400aton an apecisafte ofte collseced with food L. stomach, Table 68. (continued) Fall -Ined Totals NO. Percent NO. Percent Average Sector Food Item Stomachs Occurrence 2 Bolus Food Item St machs Occurrence Z Bolus Creeks Penwus setiferus 7 63.6 84 Pisces 10 45.5 76 Places 2 18.2 90 Penaeuz setifems 7 31.8 84 5 't 2 9.1 45 -ellifer lanceolatua 2 18.2 45 Stellifer lanceolatus Anchoa hepsetus 1 9.1 90 Alpheus sp. 2 9.1 40 Menticirrhua UtWralia 1 9.1 60 Anchoa hepectus 1 4.5 90 Anchoa mitchilli 1 4.5 90 Mysidae 1 4.5 90 Decapada 1 4.5 90 Palaemnetes BP. 1 4.5 80 Mentia@irrhus Iittoralis 1 4.5 60 Sounds Pisces 19 43.2 72 Pisces 94 41.9 69 Brevoortia tyranmw 11 25.0 27 Brevoortia tyrannus 51 25.4 84 Penaeua sctiferLw 7 15.9 83 Mysidae 22 10.9 75 Penaeidae 5 11.4 56 Crustacea 15 7.5 61 Stellifer lanceolatus 4 9.1 80 Penaeue setiferuz 9 4.5 94 Crustacea, 2 4.5 35 Decapoda 9 4.5 67 Decapoda 1 2.3 90 Unidentified material 6 3.0 82 Cyathura polita 1 2.3 90 Penaeidae 6 3.0 55 Organic material 1 2.3 90 Anc4toa mitchilli 5 2.5 82 Plant detrItus 1 2.3 90 Spartina alterniflora 5 2.5 54 X, beaches Places 3 50.0 77 Pisces 12 75.0 73 Brevoortia tyrunnus 1 16.7 90 St@ellifer lanceolatus 2 12.5 90 Stellifer lanceolatus 1 16.7 90 Mysidae 1 6.3 90 Mysidae 1 16.7 90 Ak-piticirriiiis am?y-icanua 1 6.3 90 Crustacea 1 16.7 50 Bmvoortia tyrunnue 1 6.3 so Cephalopoda 1 6.3 80 Crustacea 1 6.3 50 Trachypeneus cutwty-ictus 1 6.3 <5 Offshore NONE Mysidae 1 100.0 90 Totals Pisces 24 39.3 74 Pisces 106 44.2 70 Penaeus oetiferus 14 23.0 84 Brevoortia ryrann,o 52 21.7 84 Bmwoortia tyrannus 12 19.7 88 Mystdae 25 10.4 77 Stellifer lanceolatus 7 11.5 71 Crustacea 17 7.1 56 Penaeidae 5 8.2 56 Penaeus setiferus 16 6.7 94 Crustacea 3 4.9 40 Stellifer laneeoZatus 11 4.6 76 Mysidae 2 3.3 60 Decapoda 10 4.2 69 Decapoda 1 1.6 90 Anchoa nitchilli 6 2.5 83 Cyathura polita 1 1.6 90 Unidentified material 6 2.5 82 Plant material 1 1.6 90 Penaeidae 6 2.5 55 l/ None denotes no specimens were collected with food In stomachs. t I shrimp were also ingested. In summer the major foods were menhaden, anchovies, squids and crustaceans. In fall the major foods were white shrimp, menhaden and star drum. The second shift in major food items indicated that weakfish were highly opportunistic feeders. Feeding activity, as related to the number of stomachs containing food, was greatest during spring and summer as over 81% of the stomachs ,contained food (Table 69). In fall there was a slight decline in feeding activity as the percentage of stomachs containing food dropped to 69.3%. Lowest feeding activity occurred in winter when only 62.8% contained food. Feeding activity was greatest in the creeks (84.6% contained food) and lowest on the beaches (64.0%), with the sounds midway between (73.4%). No conclusions are drawn for offshore waters as only one specimen was examined from the sector.' . At water temperatures below 15 0C over 40% of the stomachs examined were empty, indicating decreased feeding activity or low food availability or both (Table 50). As water temperatures increased to 21 0C, the per- centage of empty stomachs dropped below 16%, and at temperatures above 210C only 5% of the stomachs were empty. These figures indicate that feeding activity was greatest and food was most abundant during summer when water temperatures were highest. Weakfish are voracious feeders. Study results reveal that this species fed actively throughout the lunar cycle as 73.6% of all stomachs examined contained food (Table 51). Peak feeding activity occurred during first quarter moon and three days immediately there- after, and during the three day period prior to last quarter as over 83% of the stomachs contained food. Periods of lowest feeding activity occurred on full moon and during the three days following as only 54% of the stomachs contained food. High turbidity during full moon pro- bably resulted in prey being more difficult to capture. Fish were the most common food item for weakfish during all seasons with Brevoortia tyrannus the most common species. Mysids were the most common crustaceans consumed by weakfish. B. tyrannus was the 15th most 135 Table 69. Number and percent of weakf ish, QywsciOn regaliS, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Total Food Empty Total Food Empty Total 2 No. 2 z -NO-. Zo. 2 No. 50. NO. no. 2 Winter 1 33.3 2 66.7 3 100.0 57 64.8 31 35.2 98- 100.0 0 0.0 2 100.0 2 100.0 Spring 6 85.7 1 14.3 7 100.0 32 86.@ 5 13.5 37 100.0 9 64.3 5 35.7 14 100.0 Su r 4 100.0 0 0.0 4 100.0 fig 94.0 13 16.0 81 '100.0 1 loo.0 0 0.0 1 100.0 Fall 11 91.7 1 8.3 12 100.0 44 64.7 24 35.3 68 100.0 6 75.0 2 25.0 8 100.0 Total 22 84.6 4 15.4 26 100.0 201 73.4 73 26.6 274 100.0 16 ".0 9 36.0 25 100.0 LO L'% Offshore CA"Ined sectors Food Empty Total Food ft Total No. 2 -No'. T- %-. &-. Winter 1 @100.0 o 0.0 1 100.0 59 62..8 35 37.2 94 100.0 Spring - - 47 81.0 11 19.0 58 100.0 Summer 73 84.9 13 15.1 86 100.0 Fall 61 69.3 27 30.7 88 100.0 Total 1 100.0 0 0.0 1 100.0 240 73.6 86 26.4 326 100.0 abundant fish species and Mysidae the fourth most abundant crustacean collected in three meter trawl samples (Table 54). Therefore, preference may be more intense for B. tyrannus than for Mysids. Other food items which were common in weakfish stomachs included SteLZifer lanceaZatus and Penaeus setiferus. Both of these food items were common in trawl samples, indicating a random feeding selection or preference for these species. RED DRUM Red drum (Sciaenops oceNatus) range from Laguna Madre, Mexico to south Florida in the Gulf of Mexico and along the Atlantic coast from south Florida to New York (Fischer, 1978). Younger red drum, less than four years of age, commonly inhabit Georgia's inside waters in areas similar to that of spotted seatrout. Also, when marshlands are inundated during flood tides, they often move into these submerged areas to feed. Older red drum are commonly found in the surf zones on sandy beaches and in shoal areas associated with the mouths of major river systems such as the Altamaha River. During spawning, it is generally believed that older red drum move to offshore waters, possibly over live bottom areas. Movement and Migration From March 3, 1979 through June 22, 1982, 368 red drum were tagged and released. Length frequencies of tagged red drum in 50 mm length groups are included in Table 70. Lengths (TL) of tagged red drum ranged from 257 to 996 mm for those tagged with Howitt tags and 264 to 1,045 mm for those tagged with Floy tags. Length frequencies of red drum tagged with each tag type are shown in Table 71. Of 368 specimens tagged, 38 were tagged with both tag types in order to compare and evaluate tag retention. Table 72 lists the length frequencies of tagged red drum in 20 mm length groups by gear type. Tagged red drum were returned from August 22, 1979 through July 25, 1983. Of 368 tagged, 79 (21.5%) were recaptured and tags returned. 137 Table 70. Number tagged, number and percent recaptured, days at large and distance traveled for red drum, Sciaenops Ocellatua, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (km) Len&th Group Taned Recaptured Returned Avg. Max. Avg. Max. 251 - 300 25 5 20.0 88 214 '48.0 178 301 - 350 135 39 28.9 162 1104 17.5 161 351 - 400 65, 17 26.2 198 456 6.9 108 401 - 450 60 15 25.0 163 376 4.9 49 451 - 500 19 2 10.5 225 347 0.0 0 501 - 550 3 0 0.0 551 - 600 20 0 0.0 601 - 650 26 1 3.8 233 233 5.6 6 651 - 700 6 0 0.0 701 - 750 6 0 0.0 751 - 800 1 0 0.0 951 - 1000 1 0 0.0 1001 - 1050 1 0 0.0 Total 368 79 21.5 168 1,104 14.2 178 l/ Distance measured in kilometers from point of release to point of recapture. Table 71. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for red drum, Sciaenops oceZIatu8, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Number Number Percent (MM) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 275 20 4 20.0 22 4 18.2 325 124 36 29.0 10 134 36 26.9 375 55 16 29.1, 1 56 16 28.6 425 39 11 28.2 5 44 11 25.0 475 15 2 13.3 2 17 2 11.8 525 1 1 2 575 10 8 18 625 14 1 7.1 9 23 .1 4.3 675 6 6 725 5 1 6 975 1 1 1025 1 1 Total 290 70 24.1 40 0 0.0 330 70 21.2 NOTE: Number tagged and recaptured does not include the 38 fish tagged with both tag types. Table 72. Number of red drum, Sciaenops ocellatus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Gill Net (in)-!' Trammel Length Group (mm) 2 2-7/8 3-1/2 4-5/8 6 Net Cast Net Hook/Line Totals 250 - I - - - - 1 270 1 5 - - - - 1 7 290 1 14 - - - - 2 17 310 - 43 - - - I - 3 47 330 - 53 1 - - 1 - 1 56 350 - 36 - - - 4 - 4 44 370 - 14 - - - 5 - 3 22 390 - 7 1 - - 20 1 1 30 410 - 7 - - - 26 - 2 35 430 - 3 2 - 1 12 1 - 19 450 4 - - - 11 - 1 17 470 - - 5 - - 5 490 - 1 1 1 3 510 1 - I - - 2 530 - - - - - 550 - - - - - 1 570 1 4 2 1 - - 8 590 1 4 1 6 - - 12 610 1 - 3 8 - - 12 630 1 1 2 3 - - 7 650 - 2 3 6 - - 11 670 - 1 - 1 - - 2 690 - - I - - - 1 710 - 1 1 - - - 2 730 - 2 1 - - - 3 750 - 1 - 1 - - 2 770 - - - - - - - 790 - - - - - 2 2 Totals 7 203 5 1 16 113 3 20 368 -'/Gill net sizes are stretch mesh measurements. 0 a a a a a a Recovery rates, when separated into 50 mm length groups, ranged as high as 28.9%. Table 70 presents the number of fish released and recaptured, time at large, and distance traveled. Time at large ranged from 2 to 1,104 days with an average at large time of 168 days. Maximum distance traveled was 178 km with an average of 14.2 km. The overall recovery rate with Powitt tags was 24.1% while Floy tags failed to produce any recoveries (Table 71). Of 38 red drum tagged with both tag types, 9 (23.7%) were recovered. Six of these nine recoveries were at large from 6 to 85 days and had both tag types attached. The remaining three double-tagged red drum were at large 216 to 641 days and only the Howitt tag remained attached. Recreational fishermen were the major source of red drum recoveries, accounting for 71 (89.9%) of the 79 returns. Study activities accounted for 8 (10.1%) while commercial fishermen failed to return any recaptures (Table 11). Of 71 recreational recaptures, 41 (58%) included sufficient information to determine lengths of creel-size fish. Lengths (TL) of recreational recaptures ranged from 311 to 659 mm and averaged 447 mm (Table 14). Larger red drum were tagged, but only one was recaptured. This fish was tagged in the sound sector and recaptured on the beach in September after being at large 641 days. Unfortunately,recapture length was not available for this individual.. However, it had measured 642 mm when released, and it weighed approximately 7.3 kg when recaptured. From our length-weight curves the estimated length when recaptured was approxi- mately 900 mm (Figure 24). Large catches of adult red drum on Georgia's beaches and shoals were not uncommon in the past, but reported catches have decreased dramatically in the last 5 to 10 years. Recoveries indi- cated that recreational fishermen fishing inland waters were likely to catch red drum ranging from 300 to 700 mm (Table 13). However, reds greater than 750 mm tended to move to areas of higher salinities in beach, shoal, and offshore waters. These areas generally receive less fishing pressure than the inside waters. Of 79 recoveries, 71 produced sufficient information to determine the estuarine sector,location and season of recapture. The sounds had 141 10, the highest return rate (83.1%). Approximately the same percentage was recaptured in the sounds as was released (Table 14). Creek and beach sectors together produced the remaining recoveries (16.9%). Although larger specimens occur offshore during fall and winter, this area failed to produce any recoveries. Recovery data indicated that red drum were most abundant in the inside waters during summer and fall. Inside waters accounted for approximately 96% of all red drum recoveries (Table 15). Geor ia residents fishing in state waters accounted for 67 (94%) of 9 the 71 recreational recoveries. Of these resident fishermen 53 (79%) traveled 40 km or less to reach the location of recapture and approxi- mately 91% traveled less than 160 krn (Table 16). The principal bait used by recreational fishermen to catch red drum was shrimp. Approximately 87% of all recreational red drum recaptures were caught on live shrimp with an additional 9.8% being taken on dead shrimp (Table 17). Artificial lures and cut bait (mullet) accounted for the remaining two recoveries. Approximately 62% of the recoveries were caught in the immediate area of release. Of 79 recoveries, 70 (88.6%) were recaptured within 25 km of the tagging site. Four recoveries (5.1%) had moved from 26 to 100 km, and five (6.3%) had traveled over 100 km from the point of re- lease (Table 73). The distance traveled and time at large for nine red drum that traveled over 25 km ranged from 49 to 178 km and 47 to 215 days. The average release length of these individuals was 334 mm. Four of these were recaptured during the fall and exhibited an average north- ward movement at 112.5 km. The greatest northward movement (161 km) was to St. Helena Island, South Carolina. The other five individuals exhibited an average southward movement of 112.2 km with the greatest movement (178 km) to the jetties at St. Augustine, Florida. The individuals that moved southward were recaptured during fall, winter and spring. In general, winter was the period of greatest movement, averaging 30.8 km (Table 21). Only 5 (6.3%) were recaptured beyond Georgia waters. Also, 72% of the drum that moved out of Georgia estuaries were recovered during the fall season. 142 @' I k I f 1 4 1 41 a 0 0 0 0 Table 73. Days at large and distance traveled for red drum, Sciaenops ocellatus, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At Distance Traveled (km) Large 0 0.1-1 1-5 6-25 26-50 51-100 101-200 Total Percent I - 50 20 1 3 2 - 2 1 29 36.7 51 - 100 7 1 - 3 1 2 14 17.7 6.3 101 - 150 3 1 - - 1 5 151 - 200 1 1 - - - - 2 2.5 201 - 300 6 3 2 2 1 1 15 19.0 301 - 500 10 - - 2 - - 12 15.2 501 - 750 1 - 1.3 750 - 1,000 - - Over 1,000 1 - - - 1.3 Total 49 7 5 9 1 3 5 79 100.0 Percent 62.0 8.9 6.3 11.4 1.3 3.8 6.3 100.0 Recovery information was insufficient to ascertain seasonal move- ment trends within the estuary. Movement within the estuary appeared to be random during spring, summer and fall, and very little movement was observed during winter (Table 74). Similar movement behavior was reported for red drum in Texas bays (Simmons and Breuer, 1962). In Florida, Beaumariage (1969) reported 91.2% of the red drum re- coveries did not move significantly from their release locations. Approxi- mately 89% of the recovered Texas red drum moved less than 25 km (Matlock and Weaver, 1979). Simmons and Breuer (1962) reported little movement of red drum between Texas bays and even less between bay and gulf. In general, data indicate that small red drum on the Atlantic and Gulf coasts exhibit little movement. Movement within bays and estuaries appears to be random, usually being initiated by changing climatic con- ditions. Larger red drum generally move to beach and offshore waters and seldom return to the bays or sounds. Understandably, most tagging activities have been conducted in the bays and estuaries where red drum were more abundant, thus limiting the amount of movement, spawning and life history information available for larger red drum. Length-Weight Relationship Based on 103 specimens, ranging in length from 32 to 1,099 mm and weight from I to 14,336 g, the length-weight relationship for red drum was log W = 2.722 logL -4.220. The correlation coefficient value for length-weight for red drum was 0.9776 (P < 0.0001). Figure 24 illustrates the length-weight relationship for red drum. Least-squares regression analyses on the relation@hips between fish length and weight for male, female, and all red drum combined are shown in Table 24. The greatest lengths recorded for male and female red drum during this study were 776 and 1,099 mm, respectively. The heaviest specimens were a 4,152 g male and a 14,336 g female. The weights of Georgia red drum are com- pared with fish from other areas in Table 75. 144 Table 74. Seasonal movement of rod drum. 'ciaenur,e 0-11atue, tagged In the coastal waters of Clynn County, Georgia from January 1979 through June 1982. bir6etim Moved ft RAcwtured Taaasd VIA Length Group Caught In Area t Wit" tusty t Out Of-Ratuary Season (am) Of RAlease MAM= Inea"Wen To Creak Mt South Winter 251-300 - - - - 1 301-350 3 - - - - 351-400 2 - - - - 401-450 4 - - - - 431-500 - - - - - 501-550 - - - - - 551-600 - - - - - 6oi-650 - - - - - Total 9 - - - I Percent 90.0 - - - 10.0 Spring 251-300 - - - - I 301-350 - - I - 351-400 1 - 401-450 3 1 451-500 - - - - - 501-550 - - - - - 551-600 - - - - - 601-650 - - - - - Total 4 1 1 - I Percent 57.1 14.J 14.3 - 14.3 Su r 251-300 - 2 1 - - 301-350 14 - I - 1 351-400 4 - I - 2 401-450 2 - - - - 451-500 - - - - - 501-550 - - - - - 551-600 - - - - - 601-650 - I - - - Total 20 3 3 - 3 Percent 69.0 10.3 10.3 - 10.3 Fall 251-300 2 1 1 5 3 301-350 7 - I - 3 351-400 4 - I - 2 401-450 1 - - - - 451-500 2 - - - - 501-550 - - - - - 551-600 - - - - 601-650 - - - - - @W Total 16 1 3 5 8 Percent 48.5 3.0 9.1 15.2 24.2 Combined Total 49 5 7 5 13 Percent 62.0 6.3 8.9 6.3 16.5 145 20 W= .000060 L 2.722 17.5-- 2 n= 103 r 98 15 12.5-- 10 41 7.5-- 5 41 2.5-- 15 @O 45 60 75 90 105 120 TOTAL LENGTH (CM) a Figure 24. Length-weight relationship of red drum, Sciaenops oceZlatus, collected in Glynn County, Georgia from January 1979 through IM June 1982. 146 Table 75. Cowiparison of total length-weight relationships for several Populations of red drum, Sciaenope ocellatua. Length - Weight Weight of Fish (g) Study Location Equation m 5M 750 Boothby and Avault Louisiana logW - 2.832 logL -4.422-1/ 401 1,098 3,469 (1971) Theiling (1974) South Carolina logW - 2.740 logL -1.2961-/ 564 1,613 4,692 Bain et al. (1980) Louisiana lo&W - 3.052 logl. -5.120 442 1,312 4,523 Present Study Georgia logW - 2.722 logL -4.220 504 1,330 4,011 Equation based on standard length (m). Equation based on standard length (cm). NOTE: Standard lengths converted to total lengths using the forsula TL 1.16 SL. Age and Growth Age and growth studies based on length frequencies and scale and otolith techniques have been applied as an ageing method for young red drum (Pearson, 1929; Gunter, 1945; Miles, 1950 and 1951; Simmons and Breuer, 1962; Theiling and Loyacano, 1976; Rohr, 1980). In general, the length frequency method for determination of age was applicable for ageing red drum during the first few years. of life, but age of older red drum must be estimated with the use of hard parts. However, as found for both red and black drum, after age IV or V more than one annulus- like mark may be formed on scales and otoliths each year (Richards, 1973; Rohr, 1980). These additional marks may consist of summer and winter annuli and spawning checks (Rohr, 1980). Scales and otolith sections from 104 red drum ranging from 32 to 1,099 mm were examined. The scales from 90 (87%) individuals were con- sidered legible for age determinations. Ninety-seven percent of the specimens exhibited lengths less than 777 mm. The remaining 3% (3) possessed lengths ranging from 1,060 to 1,099 mm. Both scales and otoliths proved useful for ageing individuals less than 800 mm. However, circuli dis- conformities and closely spaced annuli made scales unreliable as an ageing structure for larger specimens. Otolith ring counts for the only three large specimens collected in Georgia ranged from 20 to 31 rings. 'Unfor- tunately, with such low numbers it was impossible to document when and how many rings were formed each year in order to estimate age of the larger red drum (Figure 25). Scales and otoliths from smaller individuals (<280 mm) collected during June and August showed no annulus, suggesting that no annulus was formed the first winter. Theiling and Loyacano (1976) reported similar findings for red drum raised in saltwater marsh impoundments in South Carolina. Red drum were approximately 16 months old when the first annulus was formed. Annuli formation on scales and otolitbs from red drum collected in Georgia were found to be relatively simultaneous. Calculation of mean monthly growth of marginal increments indicated that 148 LENGTH-OTOLITH RING RELPTIONSHIP 1200 - 1050 - 900 - 750 - 600 - z 450 0 300 150 4 8 12 16 20 2 4 28 3 2 NUMBER OF RINGS Figure 25. Empirical length/otolith ring relationship for red drum, Sciaenops oceZZatus, collected in Glynn County, Georgia. except for the first winter, scale annuli were formed only once annually for at least the first three years of life. A single annulus formation was detectable on young red drum scales from mid-February through April. In an attempt to validate the number of annuli being laid down each year, scale samples from five recaptured red drum were also compared with scale samples taken at the time of release. Unfortunately, only one specimen was at large more than 122 days and possessed additional annuli. This female specimen was tagged August 14, 1981, measured 301 mm, and possessed no scale annuli. It was recaptured February 1, 1984, exhibited a growth increase of 426 mm in 901 days, and possessed two annuli. Such findings indicate only one annulus per year for at least the first three years of life. Due to the recent recapture of this drum in relation to publication of this paper, recovery information was not included in any of the tables. Sufficient numbers of older red drum were not collected to document time of annulus formation or number of annulus-like marks formed each year. Linear regression analyses on the relationship between fish lengths and scale radii yielded a correlation coefficient value of 0.93 (P < 0.0001) which suggests back-calculations based on fish length/scale radius would be reliable for estimating fish length at time of annulus formation. The empirical and mean back-calculated total lengths for red drum through Age III are shown in Table 76. Figure 26 illustrates the length-age relationship for young red drum less than four years of age, and Table 77 shows the empirical and weighted mean back-calculated lengths for juvenile, male, female, and combined red drum. Length-age equations for young red drum are shown in Table 27. Of 11 fish species investigated, red drum exhibited the greatest mean daily growth rate during the first two years of life (Table 32). To substantiate yearly growth of young red drum, the growth rate of tagged specimens at large from 11 to 13 months was compared with annual growth estimates based on back-calculations. Recapture lengths of the seven red drum at large during this one-year interval ranged from 510 to 636 mm with an average of 582 mm which would place the average estimated fish age at approximately 1.5 years. The mean annual growth 150 Table 76. Mean back-calculated total lengths for red drum,Sciaenops ocellatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Lengths Length Range Mean Length of Successive Scale Rings Ago Number at Capture at Capture 1 2 3 0 57 32 - 434 298 1 24 225 - 636 474 378 2 8 660 - 773 718 463 656 3 1 776 776 477 630 746 Weighted Means 403 653 746 Growth Increments 403 250 93 NOTE: Lengths measured in millimeters. 105-- A= .000038 L 1.691 2 90 n= 104 r .52 75 z w _j 60 45 30 15 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 AGE (YEAR) Figure 26. Length-age relationship of red drum, Sciaenops ocellatus, collected in Glynn County, Georgia. 152 W Table 77. Number, empirical and back-calculated total lengths, and growth increments by sex and age for red drum, Sciaenope ocellatus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Age Sex 1 2 3 Juveniles Number 3 Mean Length at Capture 373 Back-Calculated Length 321 Growth Increment 321 Males Number 9 5 1 Mean Length at Capture 475 711 776 Back-Calculated Length 435 656 746 Growth Increment 435 221 90 Females Number 12 3 Mean Length at Capture 541 731 Back-Calculated Length 412 645 Growth Increment 412 233 Combined Number 24 8 1 Mean Length at Capture 474 718 776 Back-Calculated Length 403 653 746 Growth Increment 403 250 93 NOTE: Lengths measured in millimeters. _04 153 10 for seven tagged red drum was 215.7 mm, producing a mean daily growth of 0.59 mm. Estimated daily growth based on back-,calculations for,drum in their second year of life (Age I) was 0.69 mm, indicating slightly greater growth than was estimated from recapture data (Table 27). As shown in Table 78, growth rates of Georgia red drum were similar to those reported by investigators in Texas (Pearson, 1929; Gunter, 1945; Miles, 1950 and 1951; Simmons and Breuer, 1962) and South Carolina (Theiling and Loyacano, 1976). Maturity and Spawning Adult red drum occur in relatively low numbers in Georgia and are concentrated for the most part in either the beach surf or offshore habi- tat, depending on season. The greatest known concentration of adults in Georgia is in the surf zone near the mouth of the Altamaha River in the central portion of the Georgia coast. Although adult reds do occur in other locations, their numbers are quite reduced. During the first two years of this study, only the St. Simons and St. Andrew estuaries were sampled. Consequently, the adult red drum were not collected. The Altamaha River area was later included to insure collection of all size groups, but there was an unusually low occurrence of adults during this period and we were unable to collect large specimens. Adults occurred in such low numbers that a local annual red drum "channel bass" tourna- ment on the Altamaha River failed to produce a single tournament entry. The reason for this low occurrence of adults was unknown. Spawning apparently takes place at sea during fall and early winter during the time when adults have left the surf zone and migrated to open ocean waters. Personal communication with coastal anglers who fish for "stags" indicates that spawning probably takes place in offshore waters as nearly all of these fishermen report a complete absence of advanced maturity in the fish they catch in inland and surf zones. Migrating schools of larger red drum are periodically sighted during the late summer and early f allmigration which is probably a prespawn congregation. These surface schools of medium size and large reds are most often 154 Table 78. Comparison of total lengths at age for several populations of red drum, Sciaenops ocellatus. Estimated Age Study Location 1 2 3 4 5 6 7 Pearson (1929) Texas 340 540 640 750 840 Gunter (1945) Texas 400 600 Miles (1950) Texas 320 510 Miles (1951) Texas - - - 875 925 @.n Simmons and Breuer (1962) Texas 399 661 873 Theiling and Loyacano (1976).!/ South Carolina 455 606 761 860 885 930 885 Present Study Georgia 403 653 746 -!/Converted from standard lengths using the formulaTL=1.247 SL. NOTE: A dash (-) denotes ages not collected. Lengths measured in millimeters. observed in offshore waters from August to October. One instance of a gravid red drum was taken by recreational anglers from a school of subsurface reds in offshore waters in September 1981, approximately 4 miles southwest of Gray's Reef, a natural live bottom area which lies approximately 16 miles east of Sapelo Island (Captain Ken Murray, personal communication). Four mature prespawning red drum were caught while deep trolling. One "roe" female measured 1,069mm (42 inches) and weighed 13.01 kg (28.7 lb). Unfortunately, project per- sonnel were not notified of the catch until sometime later and were unable to examine these fish. Attempts by project personnel to collect large adults failed in every attempt as only nine specimens over 700 mm were collected. The largest specimen was a 1,061 mm "resting" stage female collected in March. Project design and scope partially limited the collection of large reds. Only.two large reds were collected during the entire study. The first specimen was tagged and released in April, and the other adult mentioned above was sacrificed for life history study. Both of these fish were collected from the surf zone adjacent to the mouth of the Altamaha River. No larval or postlarval specimens were identified in ichthyoplankton samples collected during this study (Table 63). However, one juvenile was collected in the 3-meter trawl in Clubbs Creek in St. Simons sound during the winter (Tables 52 and 53). Two young specimens 39 and 54 mm (TL) were collected in mid-July, and four specimens 32 to 86 mm were collected in November. Collection of these young specimens indicates that spawning probably runs from as early as June to as late as December. The smallest specimens for which sex was determined through gross examination were a 341 mm female and a 315 mm male. Both of these fish were in their second year of life. The smallest stage Il female observed was 545 mm (age I), but no stage II males were collected. The only stage IV male collected was an age II specimen 755 mm long. By compiling information from other investigations, Peret et al. (1980) reported that maturity is reached at 305-381 mm in Alabama 156 91k ow 320-395 mm in Mississippi, and 700-800 mm in Texas, and that ripe fish as small as 425 mm (two years old) had been found by Gunter (1945). Simmons and Breuer (1962) reported that spawning normally occurs at the end of the third or fourth year when the fish are 700-800 mm (SQ, but ripe fish as small as 450 mm have been found. The stages of gonadal development for red drum collected during the study are presented in Table 79. All of the fish collected from February through August exhibited stage I or "resting stage" gonads. Stage II was the most advanced level of gonadal development for females, and these were taken from September through January. The only specimen exhibiting advanced gonadal development (stage IV) was a 755 mm (4.6 kg) male collected inside St. Simons Sound on 2 September 1981 (Table 80). This specimen was collected in 30 0/oo salinity and 280C surface water temperature (Table 81). Peret et al. (1980) summarized the following information on red drum spawning in the Gulf. Along the Florida coast spawning occurs in autumn, probably beginning in September and peaking in October, and the absence of ripe females in Florida estuaries suggests offshore spawning. In Alabama the spawning season was reported as mid-August through December, peaking in mid-September through October near inlets and passes. In Mississippi it begins in September, with mature fish observed only on the Gulf side of barrier islands. In Louisiana spawning occurs from late summer through early fall, and large schools of spawning red drum are reported to congregate around major passes from August through November. Additional studies are needed on all aspects of red drum life history in Georgia to determine size and age at maturity and spawning as well as actual time and geographic location of the spawning grounds. Future studies must target the largest specimens in offshore waters during early fall and winter to collect information not obtained under the current study. As shown in Table 40, red drum exhibiting advanced reproductive stages of maturity were virtually absent from collections made in Georgia estuaries. This prohibited the determination of fecundity for 157 Table 79. Number of red drum, Sciaenops oceUatue collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage II III IV V VI VII Mouth F M F M F R F M F F M January 4 1 1 0 February 5 0 March .1 5 April 1 1 May June July 1 0 August 3 3 September 1 10 0 1 0 1 October 2 4 November December 0 1 1 0 Table 90. Stages of gonadal development for red drum. &,-ia@nqpa oct-Llatue, by month, sex and salinity gradient for fish collected in Glynn County. Georgia from January 1979 through June 1982. Surface Water Salinity_(0100) Reproductivt 0-5 6-10 11-15 16-20 -21-25 26-30 31-35 36@40 Totals Stage F -N -f-H -F-H -7 M- January I - 3 1 1 0 4 1 11 1 0 III-VII February 1 4 0 1 0 5 March 1 0 5 1 0 11-vil April I 1 0 0 1 It-vil May I-Vil June I-Vil July 0 0 II-VII - - - August I 1 0 1 0 1 3 3 3 September 1 0 1 - - 1 9 1 10 0 1 0 1 IV 0 1 0 1 V-Vll - - - - October 1 2 3 0 1 2 4 November I-Vil - December - 0 1 0 1 0 1 0 Combined 1 1 0 0 1 4 5 6 4 6 10 1 5 18 25 Tqtals 1 0 - - 2 1 IV 0 1 0 1 V-vII - - - Table 81. Stages of gonadal development for red drum, Sc-laenops ocellatue, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Temperature (OC) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 TOTALS T-M F M F M F - (0/00) Stage F M M F M T-M T M 0-5 1 - - - - - - - - 1 0 1 0 II-VII 6-10 I-Vil 11-15 1 0 1 0 1 II-VII - - - - 16-20 1 4 4 0 1 4 5 II-VII - - - - - - C-@ 3 1 0 1 3 2 6 4 21-25 11 1 0 - - 0 1 III 1 2 0 1 0 0 1 3 9 6 10 Ii 1 0 1 0 26-30 111 - - IV 0 1 0 1 V-VII - - - - 31-35 0 1 0 1 1 2 0 1 1 5 II-VII - - - - - - - - - - 1 9 6 1 3 7 14 0 1 18 25 Ii 1 0 1 0 0 1 2 1 TOTALS III - - - - IV 0 1 0 1 V-VII - - - - this species. However, fecundity estimates for Texas red drum range from 350,000 to 3,500,000 eggs (Pearson, 1929; Colura, 1974; Johnson. et al., 1977). Food Preference and Feeding Habits The population of red drum in our study area is relatively small as compared with that of spotted seatrout. Catches of red drum were usually incidental to the collection of other species, and the large adults were extremely difficult to capture even when targeted. All red drum collected were <1,100 mm. The results of stomach analyses by 100 mm length groups are pre- sented in Table 82. Of 94 stomachs examined 72 (76.7%) contained food and 22 (23.4%) were empty. Small red drum (<300 mm) showed a definite preference for crustaceans with penaeid shrimp, grass shrimp and a variety of mud crabs being the most common foods. As they increased in size (301-800 mm) they began to incorporate more fish into their diets, but crustaceans remained their staple food source. Since only one specimen over 800 mm was collected for stomach analyses, data on the large specimens are lacking. The most commonly ingested crustaceans were white shrimp (Penaeus setiferus), mud crabs (Panopeus herbstii), and sand fiddler crabs (Uca pugiZator). The most frequently ingested fish species were mummichogs (FunduZus heterocZitus) and striped mullet (MugiZ cephatus). 'With the exception of two specimens collected from the beaches, all specimens were taken from inside waters, primarily from the sounds. From the wide diversity of organisms found in stomachs from inland waters it is apparent that smaller red drum (<800 mm) are opportunistic feeders with a definite preference for shrimp and crabs (Table 82). Investigations in other states have shown similar results with crustaceans and fish accounting for most of the reported food.items in the diet of red drum. The percentages of the various food types varied with geographic location, season and size of fish (Perret et.al., 1980). Pearson (1929) reported commercial penaeid shrimp to be the top food 161 Table 82. Stomach contents of Red Drum, Sciaenope oc,'Zlatus, collected In Glynn County, Georgia from January 1979 through June 1982. Length Group (mm) Percent Average Food Item 101-200 201-300 301-400 401-500 501-600 601-700 701-800 1001-110 [email protected] n"..rrence 7 Bolus PISCES Pisces (unidentifiable) 1 2 5 1 2 1 12 16.7 42 Anchoa mitchilZi I 1 1.4 90 Brevoortia tyrannuo I 1 1.4 90 Fundulus heteroclitus 2 1 3 4.2 43 Menidia menidia I 1 1.4 80 Micy-Rvogonias undulatus I 1 1.4 80 to Mugil cephalue I 3 4.2 80 ,,phi,-hthus mhrs I 1 1.4 30 Opsanus tau 1 2 2.8 65 Syngathidae 1 1.4 90 ARTHROPODA Crustacea (unidentifiable) 2 1 2 1 8 11.1 41 Alpheus heterochelis 2 2 2.8 15 Anthuridae 1 2 2 5 6.9 43 CaUianassa atlantica I 1 1.4 70 Call,inectes sapidus 2 2 4 5.6 83 Caprellidae I 1 1.4 30 C5,angon septemspinosa I 1 1.4 90 Cyathura polita 2 1 3 4.2 70 Eurypanopeus depressus I 1 2 2.8 30 Hcxapanopeus anguatifrons I 1 1.4 4 0 Table 82. (continued) Length Group (m) Percent Average Food Item 101-200 201-300 301-400 401-500 501-600 601-700 701-800 1001-1100 Combined Occurrence Z Bolus ARTUROPODA (continued) Hatantia 2 2 4 5.6 50 Palaerwnetes sp. 1 2 3 6 8.3 38 Panopeus herbatii 1 4 3 3 11 15.3 55 Penaeus aztecus 1 1 1.4 40 Penaeur, setiferus 1 8 1 1 11 15.3 82 Penaeidae 1 1 1.4 20 Portunus g-.,*bbesii 1 1 1.4 90 Rhithropanopeus harz-isii 2 2 2.8 20 Sesarw cinerewn 1 1 1.4 10 Sesarma reticulatzon 1 2 1 4 5.6 35 Squi I la eTvsa 1 1 1.4 80 nvehypeneus constrictus 1 1 1.4 10 Uca pugilator 2 7 1 10 13.9 63 f1ca pugnax 1 6 7 9.7 73 ANNELIDA fficolea simplex 1 1 1.4 90 PLANT Detritus 2 5 7 9.7 40 Spartina alterniflora I 1 2 2.8 15 Number of stomachs: 94 Number wW percent of stomachs containIng food: 72 (76.6%) Number and percent of empty stomachs: 27 (23.4%) choice for Texas red drum and small blue crabs ranked second. He found shrimp dominant in all fish <460 mm. Yokel (1980) reported that red drum fed heavily on crustaceans throughout their range. Bass and Avault (1975) found that red drum <9 mm fed on copepods, and as length increased to 50 mm the diet shifted to Mysidacea. Boothby and Avault (1971) found little difference in food for various size groups with the principal difference being that smaller size fish fed on smaller prey species of fish, crabs, and shrimp. The top 10 food items found in red drum stomachs are presented by season and sector in Table 83. Crustaceans were the primary food source and white shrimp were the most frequently occurring species for all seasons and sectors combined (Table 83). Crustaceans were the staple food source in the creeks with white shrimp and sand fiddler crabs as top items. In the sounds the preferred foods were mud and fiddler crabs although some fish fragments were observed. Although only two specimens were collected from the beaches, penaoid shrimp and Atlantic croaker were found in stomach contents. During winter a wide variety of foods were ingested and there was high utilization of fish. The primary crustaceans consumed were grass and snapping shrimp as commercial penaeids were less abundant. The dominant fish species were mummichogs, menhaden and mullet. During spring they fed on both crabs and fish. During summer the main foods were white 1W shrimp and fiddler and mud crabs, and during fall the major foods were mud crabs, white shrimp and fiddler crabs. Boothby and Avault (1971) found seasonal differences in feeding habits with fish moreprevalent in diet during winter and spring while crustaceans became important during late spring. Food availability and feeding activity appeared greatest in the creeks as 86.7% of the stomachs contained food (Table 84). In the sounds the percentage dropped slightly to 71.0%. Only two specimens were collected from the beaches and none were collected from offshore waters. Consequently, no conclusions are drawn for these sectors. Seasonally, lowest feeding activity occurred during winter as only 164 Table $3. The 10 war frequently occurring food items found in the stomachs of red draw. @cfae, 7-1 , by season and ... t,,r io, i W@ collected in Glynn County. Georgia from January 1979 through June 1982. Winter Spring S-r-- NO. Percent Average NO. Percent Averagt Percent Awra, Sector Food Item Stomachs Occurrence Z Bolus Food Item Stomachs Occurrence Z Bol- Food Item Stomachs Occurrence Z Bol- Cz*mkx ANVU cophalus 1 100.0 90 Pisces 2 66.7 65 Penaeue oetiferun 6 37.5 87 Places 1 100.0 5 Rviopeus op. 1 33.3 90 Crustacea 3 18.8 37 Crustacea 1 33.3 60 Organic material 3 18.8 17 Callinect-ea sapidus 2 12.5 90 tica pugiLator 2 12.5 90 Palaemanet.es op. 2 12.5 20 C@@on septempiwaa 1 6.3 90 pd7wpew np. 1 6.3 80 Penaeus aztecuo 1 6.3 40 Anthuridse 1 6.3 40 (ON Sounds Pataemanetes op. 3 30.0 57 OpsanuB tau 1 50.0 90 Yba pugnax 5 20.8 76 V1 Pieces 2 20.0 55 Callinectes, sapiduo 1 50.0 90 Panop,- op. 5 20.8 36 Alpheus sp. 2 20.0 is Uoa pugilator 4 16.7 50 Buryparopeuz depreasus 1 10.0 90 Organic material 3 12.5 63 Fioidulus heteroolitus 1 10.0 90 Pieces 3 12.5 43 Bzwzvortia tyrwvw 1 10.0 90 watantis 3 12.5 37 Syngmathidae 1 10.0 90 Crustacea 3 12.5 37 Annelid& 1 10.0 90 4athum polita 2 8.3 90 Menidia menidia 1 10.0 so Anthuridae 2 8.3 65 Callinectee aqic&9 1 10.0 60 Penaeue setiferus 2 8.3 55 Smacbe. IMM-11 - - - Pisces 1 100.0 100 Mio"ogonias w%dulatus 1 100.0 so Penaeidae 1 100.0 20 Offshore NONE - - - NONE - - - NONE - - Totals Palaownetes op. 3 27.3 57 Pisces 3 50.0 73 Penaeus aetiferus a 19.5 79 Pieces 3 27.3 37 Panol ous sp. 1 16.7 90 Uca pugilator 6 14.6 63 Alpheue op. 2 18.2 15 Callinectes sapiduB 1 16.7 90 Panopeus op. 6 14.6 43 Pkndulua hoteroolit" 1 9.1 90 @,Sanus tau 1 16.7 90 Plant material 6 14.6 40 Brevoortia tyrannuo 1 9.1 90 Crustacea 1 16.7 60 Crustaces 6 14.6 37 Mdgil cephaZus 1 9.1 90 U- Pug- 5 12.2 76 Syngnathidae 1 9.1 90 Pisces 4 9.8 35 Annalida 1 9.1 90 Autburidat 3 7.3 57 Menidia menidia 1 9.1 so Seearma retioulatw 3 7.3 43 Callinectae sapidua 1 9.1 60 De-Po" 2 4.9 37 '/Now dowtes no specimens were collected vith food In stomachs. Table 83. (continued) Fall Combined Totals NO. Pex@cW iv.@rage 90. F.T,:-.nt,@WraFv Sector Food Item Stomachs Occurrence % Bolus Food Item Stomachs Occurrence Z Bolus Creeks Uca pugilator 3 50.0 90 Penaeus setiferus 8 30.8 89 Penaeus netiferus 2 33.3 90 Uca pugilator 5 19.2 84 U- Pug- 2 33.3 65 Crustacea 4 15.4 43 Sesaywu Mticulatwn 1 16.7 10 Pisces 4 15.4 35 Plant material 3 11.5 17 Callinectes sapidzw 2 7.7 90 Panopeus sp. 2 7.7 85 Uda pugnax 2 7.7 65 Palaemotwtes op. 2 7.7 20 Sesarm mticulatw 2 7.7 20 Sounds P-P- op 4 50.0 63 Panopeus op. 9 20.5 48 Pisces 2 25.0 15 Pieces 7 15.9 39 Msgil cephalua 1 12.5 90 U- pugnar 5 11.4 76 Peweua setiferus 1 12.5 90 Uca pugilator 5 11.4 42 Porturw gibbeeii 1 12.5 90 Decapoda 4 9.1 50 Notantia 1 12.5 90 Palaexvwtes op. 4 9.1 48 Callianassa atlantica 1 12.5 70 Crustacea 4 9.1 40 Oyathura polita 1 12.5 30 C@athum polita 3 6.8 70 ftnaeus setiferus 3 6.8 67 P1"t material 3 6.8 63 ft-bes WME Pieces 1 50.0 100 Aficzwpogonias undulatue 1 50.0 80 Penoeidae, .1 50.0 20 Offshore NONE NONE - - - Totals Panopeus sp. 4 28.6 63 Pisces -12 16.7 42 Pewaus setifems 3 21.4 90 Penaeua setiferus 11 15.3 82 Uca pugilator 3 21.4 so Pa-pe- op. 11 15.3 82 V- pugnax 2 14.3 65 Uca pugitator 10 13.9 63 Places 2 14.3 15 Crustaces a 11.1 41 M4gil cephalus 1 7.1 90 Uba pugnax 7 9.7 73 Portunus gibbeeii 1 7.1 90 Plant material 6 8.3 40 Decapoda 1 7.1 90 Palaowwtes op. 6 8.3 38 Callianassa atlantica 1 7.1 70 Callinectee sapidus 4 5.6 83 Ojathura polita 1 7.1 30 Decapoda -.4 5.6 so yNOM denotes no specimens were collected with food In stomachs. Table 84. Number and percent of red drum, S2Lzcnors with stomachs containing Food versus empty stomachs bv season and sector for fish collected in Glynn County, Georgia from Januarv 1979 through June 1982. Creeks Sounds Beaches Food Empty ToFa-1 Food Empty Toi-a-1 Food Empty Total No. % No. % No. % No. % No. % No. % No. % No. 2 No. 2 Winter 1 50.0 1 50.0 2 100.0 10 66.7 5 33.3 15 100.0 - - - - - - Spring 3 100.0 0 0.0 3 100.0 2 100.0 0 0.0 2 100.0 1 100.0 0 0.0 1 100.0 Surmner 16 84.2 3 15.8 19 10(J.0 24 66.7 12 33.3 36 100.0 1 100.0 0 0.0 1 100.0 Fall 6 100.0 0 0.0 6 100.0 8 88.9 -1 11.1 9 100.0 - - - - - - Total 26 86.7 4 13.3 30 100.0 44 71.0 18 29.0 62 100.0 2 100.0 0 0.0 2 100.0 Offshore Combined Sectors Food Empty Total Food Empty Total No. % No. % No. % No. % No. % No. % Winter - - - - - - 11 64.7 6 35.3 17 100.0 Spring - - - - - - 6 100.0 0 0.0 6 100.0 Summer - - - - - - 41 73.2 15 26.8 56 100.0 Fall - - - - - - 14 93.3 1 6.7 15 100.0 Total - - - - - - 72 76.6 22 23.4 94 100.0 64.7% of the stomachs contained food. Peak activity occurred during spring and fall with ov@r 93% containing food (Table 84). At tempera- tures below 200C only 67% contained food while at temperatures above 210C the percentage jumped sharply to 80% (Table 50). Feeding activity was greatest from last quarter through the three day period preceding new moon (Table 51). Lowest feeding activity took place during new moon when 50% of the stomachs examined were empty. Further discussion of feeding activity by lunar phase is pre- cluded by limited sample size. Crustaceans were the most common food item for red drum during all seasons. Penaeus setiferus was the most frequently occurring species during all seasons followed by a variety of other decapods such as Panopeus herbstii and Uca pugilator (Table 82). P. setiferus and P. herbstii were the 3rd and Ilth most abundant crustaceans collected in three-meter trawl samples, respectively (Table 54). The most com- monly occurring fish in red drum stomachs were Fundulus heteroclitus, Brevoortia tyrannus, and Mugil cephaZus. Only B. tyrannus occurred in the top 15 most abundant fish species collected in the three-meter trawl samples.* Although fish were a common food source, the data indicated that crustaceans were the preferred food items. SOUTHERN FLOUNDER Southern flounder (ParaZichthys Lethostigma) are geographically distributed in the Gulf of Mexico from Texas to south Florida and along the Atlantic coast from south Florida to North Carolina (Fischer, 1978). Flounders prefer smooth mud and sand bottom areas conducive to bury- ing beneath the sediment surface where they are concealed against pred- ators while awaiting unwary prey. Flounders are often found feeding on crustaceans and juvenile fish during ebb tides at mouths of small tidal creeks. They are found at all depths within the estuaries but are quite common on shallow flats especially during flood tides. 168 Movement and Migration From January 17, 1979 through June 28, 1982, 1,181 southern flounder were tagged and released. Length frequencies of tagged flounder in 50 mm length groups are included in Table 85. Lengths (TL) of specimens tagged with Howitt tags ranged from 118 to 629 mm while those tagged with Floy tags ranged from 145 to 451 mm. Length frequencies of flounder tagged with each tag type are shown in Table 86. Length frequencies of southern flounder collected for tagging are listed by 20 mm length groups and gear type in Table 87. Tagged southern flounder were returned from March 21, 1979 through July 7, 1983. Of 1,181 flounder tagged, 75 (6.4%) were recaptured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged as high as 7.9%. Recovery rates ranged from 4.3 to 7.9 percent for all 50 mm length groups between 151 and 500 mm (Table 85). Within this length range recovery rates indicated little difference in tag retention or fishing pressure as related to size of fish. The number of flounder released and recaptured, time at large, and distance traveled appear in Table 85. Time at large ranged from 2 to 716 days and averaged 215 days. Distance traveled ranged as far as 556 km with an average of 53.8 km. The overall recovery rate for southern flounder tagged with Howitt tags was 6.6% and with Floy tags it was 3.9% (Table 85). Recreational fishermen were the major source of southern flounder recoveries with 41 (54.7%) of the 75 returns. Commercial fishermen returned 30 (40.0%) tags, while study activities accounted for the re- mining 4 (5.3%) recoveries (Table 11). Of 41 recreational recaptures, 28 (68%) included sufficient information to determine lengths of creel size fish. Lengths (TL) of recreational recaptures ranged from 222 to 436 mm with an average size of 340 mm (Table 12). Length frequencies of recreational recoveries indicate that 96% of the fish ranged from 250 to 450 mm (Table 13). Of the 75 recaptures, sufficient information was obtained on 69 (92%) fish to determine the location and season of recapture. The sounds had the highest return rate at 44.9% while the creeks had the 169 Table 85. Number tagged, number and percent recaptured, days at large and distance traveled for southern flounder, Paralichthya lethostigma, in 50 mm, length groups. Number Number Percent Days At Large Distance Traveled (km Length Group Taimed Recaptured Returned Avg. max. Avg. Max. 101 - 150 2 0 0.0 151 - 200 70' 3 4.3 117 237 36.5 89 201 - 250 243 14 5.8 264 716 50.7 219 251 - 300 494 39 7.9 224 535 42.7 363 301 -350 209 11 5.3 202 500 110.6 556 351 -400 88 4 4.5 214 423 81.2 224 401 -450 43 3 7.0 49 130 0.0 0 451 -500 19 1 5.3 113 113 7.4 7 501 -550 7 0 0.0 551 -600 3 0 0.0 601 -650 3 0 0.0 Total 1,181 75 6.4 215 716 53.8 556 I/ Distance measured in kilometers from point of release to point of recapture. db di Table 86. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for southern flounder, Paralichthys lethostigma, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numb&r Number Percent (mm) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 125 1 1 2 175 50 2 4.0 20 1 5.0 70 3 4.3 225 205 13 6.3 38 1 2.6 243 14 5.8 275 474 39 8.2 20 494 39 7.9 325 195 9 4.6 14 2 14.3 209 11 5.3 375 so 4 5.0 8 88 4 4.5 425 42 3 7.1 1 43 3 7.0 475 is 1 5.6 1 19 1 5.3 525 7 7 575 3 3 625 3 3 Total 1,078 71 6.6 103 4 3.9 1,181 75 6.4 Table 87. Number of southern flounder (ParaZichthys Zethostigma), tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Fish Gill Net (stre tch mesh:inches) Trammel Cast Hook and Length (mm) 2 2 7/8 3 1/1 4 5/8 6 Net Seine Trawl Net Trap Line Totals 110 1 1 130 0 0 150 1 7 8 170 0 12 12 190 .2 2 47 51 210 1 3 3 60 1 68 230 1 4 15 77 1 2 0 100 250 0 20 1 2 11 135 0 2 2 173 270 1 10 1 0 11 172 2 2 1 200 290 1 13 0 1 10 170 0 1 0 196 310 0 13 0 1 7 90 0 1 1 113 330 1 10 1 0 1 10 51 0 0 1 75 350 0 10 1 0 0 3 1 24 0 1 2 42 370 0 5 0 1 0 5 1 26 0 0 1 39 390 1 4 1 1 0 8 0 11 1 1 0 28 410 9 2 2 3 0 5 0 0 21 430 7 2 2 0 6 0 1 18 450 3 2 2 1 1 1 1 11 470 2 1 3 0 3 9 490 3 0 0 0 0 3 510 2 0 1 1 1 5 530 2 0 0 2 550 0 1 1 2 570 0 0 0 590 0 1 1 610 1 1 2 630 1 1 TOTALS 6 124 7 6 9 97 4 902 4 11 11 1181 lowest at 10.1%. The percentage of flounders released in the creeks and sounds was proportionally higher than the percentage recaptured (Table 14). In contrast, the return rate from the beaches and off- shore waters was proportionally higher than the release rate. Fishing pressure in offshore waters was primarily from commercial shrimp trawlers. Of 69 flounder recoveries from which information was obtained, 56 (81%) were recaptured during summer and fall, with fall producing approximately half (50.7%) of all recoveries (Table 15). Winter pro- duced the lowest return rate of only 2.9%. Georgia residents fishing in state waters accounted for 27 (66%) of the 41 recreational recaptures. Of these resident fishermen, 22 (81%) traveled 40 km or less to reach the location of recapture and approximately 89% traveled less than 80 km (Table 16). In general, most flounder were caught incidentally while fishing for spotted seatrout. The principal bait used by recreational fishermen to catch southern flounder was shrimp, with approximately 72% of all recoveries caught on live shrimp and 8.0% on dead shrimp (Table 17). Sixteen percent of the recoveries were caught on live minnows while artificial lures accounted for the remaining 4%. Avid flounder fishermen use primarily live mummichogs and small mullet as bait. Although most recoveries were caught on live shrimp, project personnel identified fish to be the preferred food item of this species (Table 97). Approximately 19% of southern flounder recoveries were caught in the immediate area of release. Of 69 recoveries, 48 (69.6%) were recaptured within 25 km of the tagging site (Table 87). Other dis- tances traveled and recovery rates were as follows: 25-100 km (13.1%); 101-300 km (13.1%); 301-500 km (2.9%); and over 500 ku.. (1.4%) (Table 88). Although black drum exhibited the greatest individual distance traveled (619 km) for all species studied, southern flounder exhibited the greatest average distance at 53.8 km. Also, southern flounder exhibited the 173 10 Table 88. Days at large and distance traveled for southern flounder, Paralichthys lethostigma, tagged in Glynn County, Georgia from January 1979 through June 1982. Distance Traveled (km) Days At 51- 101- 201- 301- Over Large 0 0.1-1 1-5 6-25 26-50 100 200 300 500 500 Total Percent- 1 - 50 8 - 2 8 - - - - - 1 19 27.6 51 - 100 - - 1 4 2 1 - 8 11.6 101 - 150 3 - 1 3 - - 7 10.1 151 - 200 - - 2 - 1 1 - - 4 5.8 201 - 300 1 - 5 2 - 1 - - 1 - 10 14.5 301 - 500 1 1 - 6 1 2 4 3 1 - 19 27.5 501 - 750 - - - 1 - - I - - 2 2.9 Total 13 1 11 23 5 4 4 5 2 1 69 100.0 Percent 18.9 1.4 15.9 33.3 7.3 5.8 5.8 7.3 2.9 1.4 100.0 ti highest percentage (17.4%) of individuals traveling more than 100 km. Of the 15 specimens recaptured more than 50 km from the release site, 13 (87%) had moved southward an average distance of 176 km. Seven of these 13 were recaptured during spring and had traveled an average distance of 277 km. All southward recaptures were recovered during spring, summer, and fall. Only two recoveries traveled more than 50 km to the north. One recovered during the fall had traveled 89 km, and the other was recaptured during the spring near Surf City, North Carolina, after traveling 556 km. Recovery data indicated the greatest movement occurred during spring with an average distance of 202.2 km (Table 21). Only 22 (32%) of all recoveries were caught within their estuary of release (Table 89). Recoveries within the estuary were during the summer and fall. The direction and season of greatest movement out- side the estuary was southward during the fall, indicating movement to higher salinity areas and warmer waters. Length-Weight Relationship The length-weight relationship for southern flounder, based on 233 specimens ranging from 125 to 700 mm and 23 to 4,771 g., was as follows: log W = 3.091 Log L -5.157. The correlation coefficient value for length-weight for southern flounder was 0.9802 (P < 0.0001). Least- squares regression analyses on the length-weight relationships for male, female, and all southern flounder combined are shown in Table 24. Figure 27 illustrates the length-weight relationship for southern flounder. Length-weight relationship calculated for Georgia southern flounder showed isometric growth (b = 3.091). The greatest lengths recorded for males and females were 362 and 700 mm, respectively. The heaviest specimens weighed 595 g for males and 4,771 g for females. Age and Growth Although several members of the genus ParaZichthys have received extensive research in the northwest Atlantic, comparatively limited 175 Table 89. Seasonal movement of southern flounder, Paralichthy8 Zethoetimga, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved ft Recaptured Talsed Fish Length Group Caught In At" MON t Out Of Latuary Season (M) Of Release CreekobtarealaftackWithIMVo Creak North South Winter 151-200 - - 201-250 - - 251-300 - - 1 301-350 - - 1 - 401-450 - - - - 451-500 - - - - Total I - I Percent 50.0 50.0 Spring 151-200 - - - I - 201-250 - - - - 2 251-300 - - - 1 4 301-350 - - - 1 1 351-400 - - - I - 401-450 - - - - - 451-500 - - - - - Total - - - 4 7 Percent - 36.4 63.6 Summer 151-200 1 201-250' - - - 1 251-300 3 2 1 1 3 301-350 3 1 - - 3 351-400 - - - - 2 401-450 - - - - 451-500 - - - - Total 6 3 1 2 9 Percent 28.6 14.3 4.8 9.5 42.8 Fail 151-200 - - - 1 - 201-250 3 1 - - 4 251-300 1 2 - 2 13 301-350 2 - - - 3 351-400 1 - - 1 401-450 - - - - 451-500 - I - - - Total 7 4 - 3 21 Percent 20.0 11.4 - 8.6 60.0 Combined Total 13 7 2 9 '.38 Percent 18.8 10.2 2.9 13.0 '55.1 t I 4 W= .000007 L3.091 3.5-- 2 n= 233 r 98 3 2.5-- r 2 FIJ .5 10 @O 30 40 50 60 70 80 TOTAL LENGTH (CM) Figure 27. Length-weight relationship of southern flounder, ParaZichthys Zethostigma, collected in Glynn County, Georgia from January 1979 through June 1982. 177 work has been devoted to ageing southern flounder. Ageing techniques usually employed for southern flounder were length frequencies and otolith analyses (Stokes, 1977). Shepherd (1980) conducted a compara- tive study of various ageing methods for summer flounder including length frequencies, scales, otoliths, and dorsal fin rays and con- cluded "scales and fin rays are preferred because the annuli are usually more distinct." However, Shepherd added "...alternative methods using scales and fin rays will give comparable results to those obtained from otoliths." Therefore, we concluded scales and otoliths were re- liable for ageing southern flounder. Scales from 233 specimens ranging from 125. to 700 mm were examined, and 198 (85%) samples were considered legible for age determination. Otoliths from these 198 fish were also examined to document the validity of annuli counts made from scales. Annuli formation on scales of south- ern flounder appear as abrupt changes in the spacing of circuli patterns. As with many temperate fishes, rapid growth of young individuals often made the first annulus indistinct and difficult to detect. Year-mark counts on scales and otoliths from the same fish were found to be rela- tively consistent except during February, when otolith ring formation was frequently detected slightly earlier than the scale annulus. The calculation of mean monthly growth of marginal increments validated that scale annuli were formed only once annually. A single annulus formation was detectable on southern flounder scales during February and March, with all scales bearing recent annuli by early April. Linear regression analyses on the relationship between fish length 2 and scale radius were performed. The r value of 0.87 (P < 0.0001) suggests the relationship was sufficiently linear to warrant simple proportion calculations to determine fish length at time of annulus formation. The empirical and mean back-calculated total lengths at age for southern flounder are shown in Table 90. Figure 28 illustrates the length-age relationship for southern flounder, with the principle of least squares employed to draw the line of best fit. Length-age 178 Table 90. Mean back-calculated total lengths for southern flounder, Parazichthys Zethostigma, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Length Range Mean Length Lengths of Successive Scale Rin&s Age Number at Capture at Capture 1 2 3 4 5 6 0 45 125 - 286 201 1 103 155 - 382 276 167 2 36 270 - 520 386 134 315 3 9 362 - 588 496 144 312 431 4 3 629 - 664 645 233 382 532 617 5 1 622 622 131 289 425 503 589 6 1 700 700 109 268 418 571 620 680 Weighted Means 158 317 451 585 605 680 Growth Increments 158 159 134 134 20 75 NOTE: Lengths measured in millimeters. 70 A= .002259 L 1.191 2 n= 233 r 63 60 0 50 F_ 0 z Ld 40 0 30 20 z 10 1 2 3 4 5 6 7 AGE (YEAR) Figure 28. Length-age relationship of southern flounder, Para- Zichthys Zethostigma, collected in Glynn County, Georgia. 180 equations appear in Table 27. Table 91 presents the empirical and weighted mean back-calculated lengths for juvenile, male, female, and combined southern flounder. The annual growth rates determined from back-calculations were compared to the mean growth rates for nine southern.flounder at large from 11 to 13 months. Their average length when tagged was 298 mm or approximately age II. Back-calculation data revealed the annual growth rate of flounder in their third year of life to be between 134 and 159 mm (Table 91). However, the annual growth estimate cal- culated from recapture data was approximately half the growth (73 mm) derived from back-calculations. Considering that growth rates based on back-calculations of Georgia fish were similar to rates reported for Texas flounders (Stokes 1977), it was assumed that tagging may have had a detrimental effect on the growth rate of this species. The oldest southern flounder collected were an age III male and an age VI female. Stokes (1977) reported maximum ages of female and male Texas southern flounder to be IV and II, respectively. Lengths of Georgia and Texas flounder were comparable for fish of similar sex and age. Maturity and Spawning The southern flounder is the most common flounder in both commer- cial and recreational catches in Georgia waters. Little is known about spawning activity for this popular species because little, if any, spawning activity occurs in inshore waters. Mahood et al. (1974) found that young southern flounder were taken in Georgia throughout the year in seining operations with peak abundance during May. The smallest southern flounder for which sex could be deter- mined through gross examination were 130 mm (Age 0) for females and 232 mm (Age I) for males. Unfortunately, an insufficient number of adult specimens were collected to determine length and age at first spawning as spawning apparently takes place at sea outside our study area. 181 Table 91. Number, empirical and back-calculated total lengths, and growth increments bV sex and age for southern flounder, PuzaZichthys collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Age Sex 1 2 3 4 5 b Juveniles Number 51 14 Mean Length at Capture -256 332 Back-Calculated Length 145 281 Growth Increment 445 136 Males Number 7 0 1 Mean Length at Capture 260 362 CO Back-Calculated Length 119 244 342 Growth Increment 119 125 98 Females Number 45 22 8 3 1 1 Mean Length at Capture 299 420 512 645 622 700 Back-Calculated Length 173 334 460 585 605 680 Growth Increment 173 161 126 125 20 75 Combined Number 103 36 9 3 1 1 Mean Length at Capture 276 386 496 645 622 700 Back-Calculated Length 158 317 451 585 605 680 Growth Increment 158 159 134 134 20 75 NOTE: Lengths measured in millimeters. The sexes and maturity stages of 114 southern flounder examined during this study are presented in Table 92. All specimens old enough to determine sex exhibited early stages of gonadal development (stages I-III). Of all females examined, 92% were stage 1, 7% were stage II, and only 1% (1 specimen) had reached stage III. Males showed even less development as 91% were stage 1, 9% were stage II, and no stage III development was observed. Maturity stages are presented by month and salinity in Table 93. The only stage III female observed was collected during August in waters with salinity in excess of 31 0/oo. This high salinity level is typical for Georgia beaches and offshore waters, and is probably an indicator that this fish was preparing to move offshore in anticipation of the fall and winter spawning season. Maturity stages are presented by temperature and salinity in Table 94. Since no advanced stages of gonadal development were en- countered in inshore waters, little can be surmised concerning maturity and spawning. No larval or postlarval southern flounder were identified in ichthyoplankton samples. However, four unidentified postlarval speci- mens of the family Bothidae were collected in February (Table 63). Only one young southern flounder was collected in the 3-meter trawl, and this specimen was collected during the fall on the beach (Tables 52 and 53). Ginsburg (1952) suggested that spawning probably takes place in late fall and early winter and that the season was probably extended. McClane (1965) reported that spawning apparently takes place in winter as ripening fish have been caught in October, and young fish one to two inches are taken from December to April off the Texas coast. Stokes (1977) reported that sex differentiation in Texas flounders became possible when fish were approximately 70 mm (6.7 in). He reported that this species progretsed from stage 0 (no gonads present) to stage I (immature) to stag6 II (maturing) during the first year of life, and that adults in developing condition began to enter the catch 183 Table 92. Number of southern flounder, Paralichthys lethostigma, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage II III IV V VI VII Month F M F M F M F T M F M F M January February 2 0 March .3 1 April 5 0 May June 12 0 1 0 July 25 3 2 0 August 21 0 1 0 1 0 September 11 5 2 0 October 8 0 November 1 0 December 7 1 0 1 ti Table 93. Stages of gonadal development for southern flounder. ParaLi,-;,,@yit 1-?thoatiotma, by month, sex and salinity gradient for fish collected In Glynn County, Georgia from January 1979 through June 1982. Surface Water Salinity (0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 Tots a Mquill stage F F M F M F H F M F January I-VII February I 1 0 1 0 0 11-VII March 1 2 1 1 0 II-Vil April 1 0 2 0 2 0 5 0 II-VII May I-Vil Jam 1 4 0 7 0 1 0 12 0 II 1 0 1 0 III-Vil - - - July 1 3 0 13 2 9 1 - - 25 3 co II - - - - 2 0 - - 2 0 U1 III-VII - - - - - - - - - August 1 10 0 7 0 4 0 - - 21 0 11 1 0 1 0 III 1 0 1 0 TV-Vil - September 1 2 0 5 5 1 0 3 0 11 5 Il 1 0 1 0 2 0 III-VII October I 1 0 3 0 2 0 2 0 8 0 II-VII November I 11 1 0 1 0 III-VII December 1 4 1 3 0 7 1 11 0 1 0 1 III-Vil Combined 1 3 0 8 6 27 1 38 2 18 1 94 10 Totals 11 - - 1 0 2 1 2 0 2 0 7 1 III 1 0 1 0 W-Vil Table 94. Stages of gonadal development for southern flounder, ParaZiehthys lethostigma. by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Temperature ( 0C) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Totals (0/00) Stage F M F M F M F M -F M F M F T 6-10 1 - - - - - - 1 0 1 0 II-VII - - - 11-15 1 1 0 2 0 3 0 II-Vil - -- - - - - 1 1 1 0 5 5 E 6 16-20 11 - - - 1 0 1 0 III-Vil - - - - - - - Co 1 5 1 1 0 1 0 20 0 - - 27 1 21-25 Il 0 1 - - - - 2 0 - - 2 1 III-VII - - - - - - - - - - - - 1 4 0 - - - - 3 0 20 2 11 0 38 2 26-30 11 - - - - 1 0 - - 1 0 - - 2 0 III-VII 1 3 0 11 1 4 0 18 1 31-35 11 - - 1 0 1 0 2 0 111 1 0 1 0 IV-VII - - - - 1 4 0 5 1 4 1 9 0 58 8 15 .0 95 10 11 0 1 1 0 5 0 1 0 7 1 TOTALS III - - - - 1 0 - - IV-Vil in mid-September. From October through December the adults showed stage IV (developed) and stage V (gravid) development. He further reported that they were gravid for the first time at two years. Laswell, Lyons and Bailey (1978) used carp pituitary hormone to in- duce spawning in southern flounder in the laboratory and found that the eggs hatched in 40 by at 220C water temperature. More studies are needed on this species in Georgia as it was difficult to attain sufficient data on maturity and spawning from our sampling design and study area. Offshore work should be done with trawls during fall and winter to collect the large spawners. Sex ratios favored females in all length groups with an overall ratio of 9.5:1 (Table 41). Males comprised 7% of the catch except in a salinity range of 16-20 0/oo where six (40%) of the 15 specimens were males (Table 93). As shown in Table 40, southern flounder exhibiting advanced re- productive stages were virtually absent in collections made in Georgia estuaries, prohibiting the determination of fecundity for this species. Food Preference and Feeding Habits The food items ingested by southern flounder are presented by fish size in 100 mm length groups in Table 95. Of 221 stomachs examined, 113 (51.1%) contained food and 108 (48.9%) were empty (Table 96). Small specimens (<200 mm) consumed nearly equal proportions of fish and crus- taceans. In specimens 201 to 400 mm, there was a sharp increase in the amount of fish being consumed with the bay anchovy (Anchoa mitchizzi) and sea catfish (Arius feZis) being dominant. The major crustaceans were white shrimp (Penaeus setiferus) and mantis shrimp (SquMa empusa). Specimens over 400 mm showed a definite preference for fish. Surpris- ingly, the dominant species ingested was sea catfish although menhaden (Brevoortia tyrannus) and mullet (MugiZ cephaZus) were also observed. The largest southern flounder collected for stomach analyses was a 700 mm specimen weighing 4.9 kg. This particular specimen bad ingested a 292 mm (11.5 in) mullet. 187 T.bl. 95- St-h .-t.nt. f -.Lh.- ..11-t.d 1. GI- C.-t,, C-gt. f- 3- ... 11079 thr-th J- 1982. L.,zth Gr-P Food It- 101-200 201-300 301"00 401_5 501-600 R) I - 700 C-b I -d lk ,"C" .... (-Id..tifibl.) 4 27 22 4 1 58 51.1 5b A-h- iwhillf .4 90 Ali.0 f0ic 1 3 2 1 7 6.2 90 Hm@,ti. ty@., 1 3 1 3 2.7 90 0.9 71) Pw,d.l@. htc-lit- I 1 0.9 90 Lm-i- jl-i.r- 2 1.8 40 L.i@sto@ @th.@ 2 1.8 9( M@ti,imqw -ri@ 1 0.9 90 MWil -ph.1- 1 2 1.8 90 Gphidi@ -rqi-t- 1 0.9 90 St'llif" 3 2 . 7 30 Sy.ph@ I 1 0.9 90 ARMOPODA Cmst-.. (-Id..tifibl.) 2 3 5 4.4 48 C.Ili-te. epido I 1 2 1.8 60 D-.pd. I I 3 2.7 90 fto%.is @@i- I 1 0.9 90 Ogy,i&. Iph..m.tri. I 1 019 60 pal.@ te. P. I 1 2 1.8 90 P@td@ I 1 2 1.8 70 P@ @te-, I 1 0.9 90 Pe@" dwr@ 1 0.9 90 pmo@ aeti4le@ 2 3 5 4.4 90 Squi I 14 mq@ 3 3 2.7 90 7@,whvp.s I 1 0.9 90 CZFNALOPMA C.phal.p.d. (ooid@otifiabl.) 3 3 2.7 17 Lollig@la bmvi. I 1 0.9 90 AJUMIDA KOOLS. simpl- I 1 0.9 10 nXWLMIC MATERIAL 4 2 6 5.3 *m.ber of St-=hs: 221 WA.b.r .d pr.-t of ao@chs coot.l.ig food: 113 (51.11) Ou.ber -d perc-t of mty t-ch.: 108 (48.9%) t I Table 96. Number and percent of southern flounder, ParaZichthys lethostigma, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from Januarv 1979 through June 1982. Creeks Sounds Beaches Empty Empty Total Food Empty Food Tot;,- Food - Total - NO. -Z NO. % No. Z No. % No. z Wo -.% K@-.% No. X No. Z - Winter 2 50.0 2 50.0 4 100.0 8 40.0 12 60.0 20 100.0 - spring 9 75.0 3 25.0 12 100.0 5 50.0 5 50.0 10 100.0 Sumor 17 65.4 9 34.6 26 100,.0 45 48.4 48 51.6 93 100.0 7 77.8 2 22.2 9 100.0 Fall 8 42.1 11 57.9 19 100.0 10 41.7 14 58.3 24 100.0 2 50.0 2 50.0 4 100.0 Total 36 59.0 25 41.0 61 100.0 68 46.3 79 53.7 147 100.0 9 69.2 4 30.8 13 100.0 co Offshore Combined Sectors Food EMM Total Food Empty Total % No. Z -No No. Z No.- No. Winter - 10 41.7 14 58.3 24 100.0 Spring - 14 63.6 8 36.4 22 100.0 Sumer - 69 53.9 59 46.1 128 100.0 Fall - 20 42.6 27 57.4 47 100.0 Total - 113 51.1 108 48.9 221 100.0 Similar results have been reported by other investigators in other states. Stokes (1977) reported that 95% of the food found in small Texas southern flounder (10 mm to 150 mm) were invertebrates with mysids occurring most frequently. He reported that flounder in excess of 150 mm fed mainly on fish with 70% of the food items being fish. The most fre- quently occurring fish were anchovies, menhaden, croaker, and mullet. He reported penaeid shrimp as the most frequent invertebrate in fish over 150 mm. Powell and Schwartz (1979) reported that there were no major differences in the seasonal diet of flounders in Pamlico Sound, North Carolina, but reported that food consumption in juvenile flounders increased as temperature increased. Throughout the year mysids and fish were the principal food items. They also reported that older southern flounder fed almost solely on fish. The southern flounder is a voracious top line predator and an ex- cellent eating fish. However, it is probably grossly under exploited by recreational anglers in Georgia. Although coastal anglers often use mummichogs as bait for flounders, this particular prey species was iden- tified in only one stomach. Most flounders are caught incidentally on live shrimp when anglers fish for spotted seatrout. The 10 most common occurring food items found in southern flounder stomachs by season and sector appear in Table 97. Of all stomachs ex- amined, sea catfish and bay anchovy were the dominant fishes ingested while white shrimp and mantis shrimp were the dominant crustaceans (Table 97). Winter feeding activities were focused primarily on fish, with spot (Leiostomus xanthurus), blackcheek tonguefisb (Symphurus plaguisa), and star drum (SteUifer ZanceoZatus) the primary species. Crustaceans ingested during winter included mysids and grass shrimp. In spring, only fish were found in stomachs, with bay anchovy, menhaden, mullet, star drum and ladyfish (Elops saurus) being ingested. During summer, fish were again the most frequently occurring food group with sea cat- fish and bay anchovy the dominant species. Summer feeding activities, however, showed much more diversity as a variety of crustaceans were also consumed, including white shrimp, mantis shrimp, and blue crabs 190 Table 97. The 10 most frequently occurring food items found in the stomachs of southern flounder, Para!ck:@:-- bv Season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Winter Spring Sumer NO. Percent Average NO. Percent Average NO. Percent Average Sector Food Item Stomachs Occurrence Z Bolus Food Item Stomachs Occurrence Z Bolus Food Item Stomachs Occurrence Z Bol us creeks Lewstanus mmthurwe 1 50.0 100 Pisces 6 66.7 so ileces 11 64.7 40 Mysidae 1 50.0 100 Anchoa witchilli 2 22.2 100 Crustacea 4 23.5 3,8 Brevoortia tyrannuo 1 11.1 90 Larijmw fasciatus 2 11.8 40 JrZops saurue 1 11.1 70 Anchoa mitchilli 1 5.9 90 Palaem9wte8 sp. 1 5.9 90 Pundulus heteroclituB 1 5.9 90 Callinectes sapidus 1 5.9 50 Penaeidae, 1 5.9 50 Cephalopoda 1 5.9 10 SOUNds Unidentified material 3 37.5 100 Pisces 2 40.0 10D Pisces 27 60.0 42 pazaamwiet" sp. 3 37.5 100 Brewortia tymnmw 1 20.0 100 Penaeus setiferus 3 6.7 90 pieces 2 25.0 100 Atigil cephalus 1 20.0 100 Squilla eMusa 3 6.7 90 4pp%a- plagiusa 1 12.5 100 Stellifer lanawlatue 1 20.0 100 Decapods 3 6.7 90 Stellifer lawoolatus 1 12.5 100 Cephalopoda 2 4.4 20 Penaeuo astecus 1 2.2 90 PenaeuB dworarw 1 2.2 90 Lolliguwuta brevis 1 2.2 90 7mchypewue con8trictus 1 2.2 90 Arius felie 1 2.2 90 leaches ="I-/ 00" Arius felis 5 71.4 100 Anchoa mitchilli 1 14.3 100 Brevoortia tpunnus 1 14.3 100 Offshore NOM NONE - - - Total& Unidentified material 3 30.0 90 Pisces 8 57.1 63 Pisces 38 55.1 41 Pieces 2 20.0 90 Anchoa mitchilli 2 14.3 90 Arius felis 6 8.7 90 Liriostowsw zmOnwue 1 10.0 90 Bywpoortia tyranm4s 2 14.3 90 Crustaces 4 5.8 38 Mysidas 1 10.0 90 Ahdgil cephalue 1 7.1 90 Anchoa mitchilli 3 4.3 90 -%pp@-- plagiusa 1 10.0 90 Stellifer Imiceolatue 1 7.1 90 Penaeue setiferua 3 4.3 90 Stellifer lanoeolatue 1 10.0 90 ATOPO eaurue 1 7.1 70 Squi I Za oWusa 3 4.3 90 Palasmonetes, op. 1 10.0 90 Decapoda 3 4.3 90 Cephalopoda 3 4.3 17 Callinectee sapidua 2 2.9 60 -Vft- denotes 00 8POCIEfts were collected with food in stomachs. Larisius faaciatue 1 1.4 40 Table 97. (continued) Fall CAMbi Totals 140. Percent Average 140. Percent Sector Food Item Stomachs Occurrence % bolus Food Item Stomachs Occurrence 2 Bolus Creeks Pisces 3 37.5 100 Places 20 55.6 60 , "tf -41ifer lanoculatuo 1 12.5 100 Crustacep. 4 11.1 38 Ophidion ftirvjinat&n 1 12.5 100 Anchoa Mi t,-;i,* 11 i 3 8.3 90 Penacus setiferas 1 12.5 100 Penaeidae 2 5.6 70 Penaeidae 1 12.5 100 Larimus fasciatus 2 5.6 40 Unidentified material 1 12.5 too Lrioatonsw xanthuruB 1 2.8 90 Penaeus setiferua 1 2.9 90 Palaemonetes op. 1 2.8 90 h4miullts il,,t@,,?-Oclitus 1 2.8 90 Otellifcv Zan,-,.,vlatu@: 1 2.8 90 -Sounds Pisces 6 60.0 75 Pisces 37 54.4 52 Lcioetomuit xan thurus 1 10.0 90 Penaeus setiferue 4 5.9 90 Arius feliv 1 10.0 90 Decapada 3 4.4 92 A640,i I cepkalus 1 10.0 90 Squilla empusa 3 4.4 90 POWOUS actiferue 1 10.0 90 Unidentified material 3 4-.4 '90 C@yridcs alphaerostris 1 10.0 60 Arius felis 2 2.9 90 Inorganic material 1 10.0 40 Mv4gil cephalur 2 2.9 90 Stellifer law-colatus 2 2.9 90 Inorganic materials 2 2.9 65 Cephalopoda 2 2.9 20 Beaches Pisces 1 50.0 100 Arius fcliz 5 55.6 90 Crustacen 1 50.0 100 Pisces 1 11.1 90 Anc;u)a nrit,-hilli 1 11.1 90 Brrzkjortia ti,-annus 1 11.1 90 Crustacea 1 11.1 90 Offshore WWI' - - - NNE - - - Totals Places 10 50.0 31 Places 58 51.3 56 Penaeus octifena; 2 10.0 90 Arius felis 7 6.2 90 Leiostomus xanthun@w 1 5.0 90 Anchoa mritchilli 5 4.4 90 Arius felio 1 5.0 90 Penarua setiferus 5 4.4 90 Mdgil cephalus 1 5.0 90 Crustacea 5 4.4 48 Stc1lifer lanceolatua 1 5.0 90 Unidentified material 4 3.5 90 C@*idion marginatzon 1 5.0 90 Bmvoortia. tyrannus 3 2.7 90 Crustacea 1 5.0 90 Stellifrr lanceolatus 3 2.7 90 Penseldne 1 5.0 90 Squilla empusa 3 2.7 90 Ogyridetr alphaprostris 1 5.0 60 Decapoda 3 2.7 90 Mone denotes no specimens were collected with food to stomschs. ( I ( I ( I t I A Ah Alk (CaZZinectes sapidus). Squid were also found in three stomachs during summer. Fall feeding habits also included a variety of organisms, but fish were again the preferred food item. There appeared to be no specific species preferred as food. White shrimp were the dominant crustacean although other species of crustaceans were found. Feeding activity was apparently greatest during spring when 63.6% of the stomachs contained food (Table 96). During fall and winter less than half of the stomachs examined contained food with 42.6% and 41.7%, respectively. In the creeks, 59.0% of the stomachs contained food, but in the sounds the average dropped to 46.3%. Although only 13 stomachs were examined from the beaches, 69.2% contained food. No stomach samples were collected from offshore waters. Feeding activity seemed to be greatest when water temperatures were between 16 and 250C as 60% of the stomachs contained food (Table 50). At temperatures below 150C only 41.5% contained food, and at tempera- tures above 260C,the figure was only 52%. Feeding activity appeared greatest during the three day period fol- lowing first quarter and during the three day period prior to new moon with 75% and 68.8% of the stomachs containing food, respectively (Table 51). Lowest feeding activity was observed during the three day period before and including full moon, and during new moon and the three day period thereafter as over 61.5% of the stomachs were empty. As observed in Table 97, Anchoa mitchiZZi and Arius feZis were the most frequently occurring fish in southern flounder stomachs while Penaeus setiferus and SquiZZa en7pusa were the major crustaceans. All four of these prey species were included in the top 15 most commonly occurring organisms collected with three-meter trawl (Table 54). All four of these organisms were bottom oriented and highly mobile. There- fore, considering the lay and wait feeding behavior of flounders, pre- dation on these food items was probably greater than for less active or upper water column oriented species. In general, our data indicate southern flounder were opportunistic feeders, consuming any edible species passing within striking range. 193 10 SUMMER FLOUNDER The geographical distribution of the summer flounder (ParaZichthys dentatus) includes the Atlantic coast from Maine to Florida and the northeastern Gulf of Mexico (Dahlberg, 1976). Younger summer flounder, less than two years of age, prefer habitats similar to that of southern flounder. However, the occurrence of older summer flounder is relatively uncommon in Georgia estuaries. Apparently, the older individuals pre- fer the higher salinity areas of the offshore waters, but juveniles are abundant in the estuaries. Movement and Migration From March 22, 1979 through March 11, 1982, 141 summer flounder were tagged. Length frequencies of tagged flounder in 50 mm length groups are included in Table 98. Lengths (TL) of flounder tagged with Howitt tags ranged 159 to 342 mm while those tagged with Floy tags were 174 to 365 mm. Length frequencies of summer flounder tagged with each tag type are presented in Table 99. Table 100 lists the length fre- quencies of summer flounder collected for tagging in 20 mm groups by gear type. Only one (0.7%) summer flounder was recaptured. This specimen was at large 167 days and traveled 19 km (Table 98). It was released in the sound and caught in offshore waters during May by a commercial shrimp trawler. Length-Weight Relationship The length-weight relationship for summer flounder, based on 25 specimens ranging from 89 to 258 tun and 7 to 168 g, was as follows: log W = 2.920 logL -4.807. The correlation coefficient (r 2, value) for length-weight for summer flounder was 0.9899 (P < 0.0001). Figure 29 illustrates the length-weight relationship for summer flounder. Age and Growth In Georgia, juvenile summer flounder were the most abundant Para- Zichthys species taken during a recent trawl survey (Virginia Baisden, pers. comm.). However, summer flounder larger than 300 mm are relatively 194 Table 98. Number tagged, number and percent recaptured, days at large and distance traveled for summer flounder, Paralichthys denratus, in 50 rM length groups. Number Number Percent Days At Large Distance Traveled (km) Length GroMR Tagged- Recaptured Returned Avg. Maw-. Avg. Max. 151 - 200 25 0 0.0 201 - 250 75 1 1.3 126 126 18.7 19 Ln 251 - 300 34 0 0.0 301 - 350 6 0 0.0 351 - 400 1 0 0.0 Total 141 1 0.7 126 126 18.7 19 l/ Distance measured in kilometers from point of release to point of recapture. Table 99. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for summer flounder, Paralichthys dentatus, tagged in Glynn Countv, Georgia fr9m January 1979 through June 1982. Howitt Tag Floy TaA Combined Length Group Number Number Percent Number Number Percent NumbO-r Number Percent tM) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaj2tured 175 16 9 25 225 54 1 l.;9 21 75 1 1.3 275 28 6 34 325 6 6 375 1 1 Total 104 1 1.0 37 0 0.0 141 1 0.7 Ah @' I @ I ( I ( I ( I 1P 0 0 0 w Table 100. Number of summer flounder, Paralichthys dentatus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length l/ Group Gill Net (in) (mm) 2 2-7/8 Trawl Trap Hook/Line Totals 150 - - 1 - 1 170 - 6 1 7 190 - - 17 - 17 210 - 1 29 1 - 31 230 - 2 26 1 1 30 250 - - 24 1 - 25 270 - 12 - 1 13 290 1 9 - 10 310 - - 1 1 2 330 - - 3 3 350 - - 1 1 370 - - 1 - - 1 Totals 1 3 130 5 2 141 I/Gill net sizes are stretch mesh measurements. 400-- 350-- W= .000016 L2.920 2 n= 25 r 99 300-- 250-- 200-- 150-- 100-- 50-- 5 10 15 20 25 30 35 40 TOTAL LENGTH (CM) Figure 29. Length-weight relationship of summer flounder, Paralichthys dentatus, collected in Glynn County, Georgia from January 1979 through June 1982. 198 uncommon in Georgia's estuarine waters, making southern flounder the most common inshore flounder. Therefore, ageing of summer flounder was limited to young specimens. Based on the findings of Poole (1961), Eldridge (1962), Powell (1974), Smith and Daiber (1977), and Shepherd (1980) as reported by Smith et al. (1981), mean total lengths of summer flounder at the time of first annulus ranged from 113 to 271 mm. Maximum ages for summer flounder ranged from age I for males and age III for females in Pamlico Sound, N.C. (Powell, 1974) to age VIII for males and IX for females from Hampton, Va. (Eldridge, 1962). The largest mean back-calculated length (691 mm) for summer flounder was reported for an age VII speci- men from Martha's Vineyard Sound, Mass. (Shepherd, 1980). Scales from 25 summer flounder ranging from 89 to 258 mm. were examined and 23 (92%) were determined to be useable for age analyses. Of these 23 specimens, only one possessed an annulus (Table 101). The remainder were all in their first year of life. Insufficient numbers of fish bearing year marks prevented documentation of time of annulus formation and growth rate. Maturity and Spawning Of the 27 summer flounder collected, only three (11.1%) were adults and these were all young females exhibiting resting (stage I) ovarian development. These females were collected from salinity above 26 0/00 and temperatures above 260C. No young summer flounder were collected in the three-meter trawl during summer and fall, but one was found in winter and three were also collected in spring (Table 52). Three of these four specimens were collected in the creeks and one came from the sound (Table 53). Four postlarval specimens of the family Bothidae were identified in ichthyoplankton samples in February, but identification to the species level was not possible. Juvenile summer flounder are often collected in inland waters, 199 Table 101. Mean back-calculated total lengths for summer flounder, ParaZichthys de ntatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Lengths Length Range Mean Length of Successive Scale Rings Number at Capture at Capture 1 0 22 89 - 258 174 1 1 207 207 143 Weighted Mean 143 Growth Increment 143 NOTE: Lengths measured in millimeters. but as they increase in size, their abundance declines due to emigra- tion from the estuaries. Mahood et al. (1974) reported that young summer flounder were taken during seining operations in Georgia from March through July, and were most abundant in May. Shipman, Baisden, and Ansley (1983) reported collecting summer flounder ranging from 13 to 335 mm with a mean length of 105 mm during a recent trawl study of juvenile marine species in Georgia. They found that summer flounder were most abundant during April and May, but none were collected during October and November. Since summer flounder prefer sandy or hard bottoms (Hildebrand and Schroder, 1928; and Ginsburg, 1952), and since most of Georgia's estuarine areas consist of primarily soft mud and mud-sand substrates, it is highly probable that this is a major contributing factor for emi- gration of this species from the estuaries to offshore waters with in- crease in size. Adult summer flounder have been collected near the man-made reefs during April (personal observation) and have been reported by spear-fishermen during July. Ginsburg (1952) reported that the spawning period for summer flounder was late fall and winter and possibly extended into spring in Chesapeake Bay, judging from available evidence presented by previous work by Hilde- brand and Schroder (1928), and by Bigelow and Welsh (1925). Smith (1969) reported that summer flounder in Delaware Bay became sexually mature in their third year, but no ripe fish were taken in Delaware Bay. He re- ported signs of ripening gonads from August through November, and the smallest male with ripening testes was 30.5 cm long. Henderson (1979) reported spawning during the autumn migration to offshore wintering grounds (approximately 150 meters depth), and that the young spend their first year in bays or inshore areas in the northwest Atlantic. She also reported that maturity was reached at age three which agreed with the findings of Smith (1969). Spawning periods for different areas range from late July through January in Narragansett Bay to December through April in North Carolina sounds (Henderson, 1979). 201 As shown in Table 40, the absence of advanced reproductive stages of summer flounder in Georgia estuaries prohibited determination of fecundity for this species. Food Preference and Feeding Habits In Georgia, summer flounder occur in relatively low numbers as compared to southern flounder. Although juveniles occur in trawl catches throughout the estuaries, larger specimens tend to move off- shore. Hence, the larger specimens were not collected in sufficient quantities to make valid conclusions concerning feeding habits. Of 27 stomachs examined, 23 (85.2%) contained food and 4 (14.8%) were empty. The contents of ztomachs containing food are presented by fish size in 100 mm groupings in Table 102. The most frequently occurring food item was mysid shrimp (26.1% occurrence) followed by grass shrimp, PaZaemonetes sp., (17.3%),and unidentified decapod crustaceans (8.7%). In specimens <100 mm mysid shrimp and grass shrimp were identified al- though sample size was limited. In specimens 101-200 mm mysid shrimp and grass shrimp were dominantbut annelid worms and fish were also ingested. In specimens 201-300 mm fish, mysid shrimp and squid were ingested. The 10 most frequently occurring food items by season and sector are presented in Table 103. The major food item during winter was mysid shrimp with a 30% occurrence rate. Other items included unidentified crustaceans and fish. In spring, mysid shrimp and grass shrimp were ingested, but only a limited sample was collected. In summer, unidenti- fied fish occurred in 33.3% of the stomachsbut staple food items were crustaceans, primarily grass shrimp and the smaller penaeid shrimp (Trachypeneus constrictus). In fall, mysid shrimp dominated other items with 60% occurrence. In general, the major foods on a year round basis were mysid shrimp and grass shrimp although fish, squid and an- nelid worms were also consumed. The major foods ingested in the creeks were fish, grass shrimp and mysid shrimp. In the sounds the major food was crustaceans, but fish 202 @ I ( I ( P w w w w Table 102. Stomachs contents of gummer flounder, Paralichthve dentatue, collected in Glynn County, Georgia from January 1979 through June 1982. Length Group (m) Percent Average Food Item 1-100 101-200 201-300 Combined Occurrence % Bolus PISCES Pisces (Unidentifiable) 1 1 2 8.7 72 An,cl@oa mitchilli 1 1 4.3 90 ARTRROPODA Crustacea (Unidentifiable) 3 3 13.0 65 Decapoda 2 2 8.7 65 Hysidae 1 4 1 6 26.1 79 Palaewnetes ap. 1 3 4 17.3 90 Trachypeneus constrictue 1 1 4.3 40 CEPRALADPODA Lolliguncula brevie 1 1 4.3 90 ANNELIDA Nicolea aimplex 1 - 1 4.3 10 PLANT Detritus 1 1 4.3 10 INORGANIC MATERIAL 4.3 90 Number of stomachs: 27 Number and percent of stomachs containing food: 23 (85.2%) Number and percent of empty stomachs: 4 (14.8%) Table 103. The 10 most frequ"tly occurring food items found in the stomachs of wimmer flounder, Paraliah0vis dentotua, by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Winter spring NO. Percent Average 160. Percent Average No. Percent Average Sector Food Item stomach$ occurrence Ibolus Food item Stomachs occurrence 2 Bolus Food Item Stomachs occurrence 2 Solux creaks am - - - NUMB Pisces 1 50.0 100 Pdlaemowtee op. 1 50.0 too Boom" PaAwsionetea op. 3 33.3 90 Palaomonetes op. 1 50.0 toG Pisces I too.0 100 Crustaces 3 33.3 83 Ilysid" SO.0 90 Unideatified material 1 11.1 90 Pisces 1 11.1 20 Plant detritus 1 11.1 10 beach** Pisces 1 100.0 100 IME reachypeneus @wtpictbw 1 33.3 45 Decapoda 1 33.3 45 I/ Annelids 1 33.1 10 Offebar* xall*@ - - - NONE - - ISM - - - Totala Palammometes sp. 3 30.0 90 Mysid" 50.0 90 Pisces 2 33.3 45 cnotac" 3 30.0 63 Pakwmopk tee op. 1 50.0 90 Falaeomwtes ap. 1 16.7 90 Pisces 2 20.0 67 rwhypoww comstriefto 1 16.7 40 Unidentified material 1 10.0 90 Decapods 1 16.7 40 Plant detritus 1 10.0 to Ammallda 1 16.6 10 IJ30m dsm*t*S 00 BP*cl@ wre collected with food in stomach*. 01' t I Table 103. (continued) Fall Combined Totals No. Percent Average No. Percent Average Sector Food Item Stomachs Occurrence % Bolus Food Item Stomachs Occurrence % Bolus Creeks Pisces 1 50.0 100 Pisces 2 50.0 90 Mysidae 1 50.0 100 Palaemonetes sp. 1 25.0 90 Mysidae 1 25.0 90 Sounds Mysidae 5 62.5 74 Mysidne 6 30.0 77 Anchoa mitchilli 1 12.5 90 Palaemonetee sp. 4 20.0 90 Decapoda 1 12.5 90 Crustacea 3 15.0 65 Lo7liguncula brevis 1 12.5 90 Pisces 2 10.0 37 Anc;;oa mitchilli 1 5.0 90 Decapoda 1 5.0 90 -721liguncula beevis 1 5.0 90 i%) Unidentified material 1 5.0 90 L- Plant detritus 1 5.0 90 beaches NONE@ Ptqces 1 25.0 90 T .rich:fpencus constrictus 1 25.0 40 Decapoda 1 25.0 40 Annelids 1 25.0 10 Offshore NONE - - - NONE - - - Total Mysidae 6 60.0 77 Mysidae 7 25.9 72 Pisces 1 10.0 90 Palaemonetes sp. 5 18.5 79 Anchoo mitchilli 1 10.0 90 Pisces 5 18.5 90 Decapoda 1 10.0 90 Crustacea 3 11.1 65 Lolliguncula brevis 1 10.0 90 Decapoda 2 7.4 65 Lolliguncula brevis 1 3.7 90 Anchoa mitchitli 1 3.7 90 Unidentified material 1 3.7 90 Plant detritus 1 3.7 90 Annelida 1 3.7 90 -!/None denotes no specimens were collectcd with food in stomachs. and squid were also ingested. On the beaches fish, crustaceans and annelid worms were important. Unfortunately, no specimens were col- lected from offshore waters. The feeding habits of summer flounder have been reported by investi- gators in other areas. Ginsburg (1952) reported that summer flounder are primarily a predaceous fish, feeding chiefly on such species of fish and small invertebrates that are readily accessible in the region it inhabits. He reported that foods include mackerel, menhaden, tautog, sand launce, silversides, butterfish and scup,and invertebrates such as crabs, shrimp, squid, sm all mollusks and sand dollars. Smith (1969) found weakfish (Cynoscion regalis) to be the primary food for summer flounder in Delaware Bay. Smith and Daiber (1977) found that the per- cent occurrence for food items of summer flounder in Delaware Bay were 11sand shrimp (Crangon septemspinosa, 41%), weakfish (Cynoscion regalis, 33%), mysid (Neomysis americana, 20%), anchovy (Anchoa sp., 7%), squid (Loligo sp., 4%), silve'rsides (Menidia menidia, 1%), herring (Azosa sp., 1%), hermit crab (Pagurus longicarpus, 1%), and isopod (OZencira prae- gustator, 1%)". Fish under 450 mm fed predominantly on invertebrates while larger specimens ate more fish. They also suggested th at the diet of summer flounder reflects local abundance of prey species. Powell and Schwartz (1979) reported no major seasonal differences in diet in young summer flounder, with mysids and fish being the principal food items. The rate of feeding in juvenile flounder decreased during winter, but increased as temperature increased. He reported that the diet of summer flounder consisted of shrimp and fish in similar quantities with in- crease in size while the diet of southern flounder consisted almost en- tirely of fish. Langton and Bowman (1981) reported the prey of eight summer flounder in the northwest Atlantic was primarily fish (47.8%) and squid (51.0%). Feeding activity was high throughout the year as 85.2% of the stomachs contained food. Over 88.9% of the stomachs contained food during all seasons except spring at 60% (Table 104). However, too few specimens were collected for further discussion. Most specimens- 206 lip W Table 104. Number and percent of summer flounder, Paralichthys dentatua, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Emp Total Food Empty Total Food Empty Total No. % No. % No. % No. % No. -No .- -_ % No. % No. % No. Winter 0 0.0 0 0.0 0 0.0 7 87.5 1 12.5 a 100.0 1 100.0 0 0.0 1 100.0 Spring 1 33.3 2 66.7 3 100.0 2 100.6 0 0.0 2 100.0 0 0.0 0 0.0 0 0.0 Summer 1 100.0 0 0.0 1 100.0 1 100.0 0 0.0 1 100.0 1 100.0 0 0.0 1 100.0 Fall 2 100.0 0 0.0 2 100.0 7 87.5 1 12.5 8 100.0 - - - - - - Total 4 66.7 2 33.3 6 100.0 17 B9.5 2 10.5 19 100.0 2 100.0 0 0.0 2 100.0 0 Offshore Combined Sectors Food- Empty Total Food Empty Total- No. % No. % No. % No. % No. % No. % Winter - - - - - - 8 88.9 1 11.1 9 100.0 Spring - - - - - - 3 60.0 2 40.0 5 100.0 Summer - - - - - - 3 100.0 0 0.0 3 100.0 Fall - - - - - - 9 90.0 1 10.0 10 100.0 Total - - - - - - 23 85.2 4 14.8 27 100.0 were collected in the sounds where 89.5% of the stomachs contained food. Again, too few specimens were collected from the other sectors to allow for analyses. Water temperature apparently had little impact on feeding activity as over 75% of the stomachs contained food for all temperature ranges except 11-150C when only two specimens were collected for a 50% food occurrence (Table 50). No conclusions can be drawn for feeding activity as related to lunar activity as too few specimens were collected. The percentages of stomachs containing food versus empty stomachs are presented by lunar phase in Table 51. BLACK DRUM Black dtum'(Pogonias.cromis) are found in the northern and eastern parts of the Gulf of Mexico, along the Atlantic coast from south 'Florida to the Gulf of Maine, around Cuba, most of the Antilles Islands, and along the Atlantic coast of South America from Guyana.to Rio Grande, Brazil (Fischer, 1978). Young black drum, less than four years of age, prefer areas near oyster reefs, piers, docks, jetties, bridge s, and generally rough bottom areas where shellfish and crustaceans are plentiful. Larger specimens inhabit inshore sandy areas such as sounds, channels and surf zones. Movement and Migration From February 12, 1979 through May 7, 1982, 352 black drum were tagged and released. Length frequencies of tagged drum in 50 mm length groups are presented in Table 105. Lengths (TL) of drum tagged with Howitt tags ranged from 163 to 410 mm while those tagged with Floy tags ranged 150 to 414 mm. Length frequencies of drum tagged with each tag type are shown in Table 106. Of 352 tagged, 36 were tagged with both tag types to compare and evaluate tag retention. Table 107 lists the length frequencies of black drum collected for tagging in 20 mm groups by gear type. 208 MW Table 105. Number tagged, number and percent recaptured, days at large and distance traveled for black drum, Pogonias cromis, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (km)- Length Group Tagged Recaptured Returned Avg. Max. Avg. Max. 101 - 150 -1 0 0.0 151 - 200 37 5 [email protected] 226 359 4.8 24 201 - 250 165 28 17.0 173 529 29.3 445 251 - 300 66 27 40.9 126 424 18.2 165 301 - 350 62 26 41.9 100 321 77.5 619 351 - 400 17 5 29.4 138 455 88.4 217 401 - 450 4 1 25.0 331 331 0.0 0 Total 352' 92 26.1 141 529 41.2 619 Distance measured in kilometers from point of release to point of recapture. NOTE: All recoveries did not possess date and location of recapture. Table 106. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for black drum, Pogonias cromis, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numbbr Number Percent (m) Tagged Returned Recaptured Tagged Returned Recaptured Taltited Returned Recaptured 125 1 1 175 25 4 16.0 11 36 4 11.1 225 109 16 14.7 31 3 9.7 140 19 13.6 275 58 20 34.5 1 59 20 33.9 325 58 24 41.4 3 61 214 39.3 375 14 5 35.7 .2 16 5 31.5 425 2 1 3 Total 266 70 26.3 50 3 6.0 316 73 23.1 NOTE: Number tagged and recaptured does not include the 36 fish tagged with both tag types. Nineteen double tagged drum were recovered. ti w qw Table 107. Number of black drum, Pogonias aromia, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length l/ Group Gill Net Un).= Trammel Cast (mm) 2 2-7/8 3-1/2 4-5/8 Net Trawl Net Trap Hook/Line Totals 150 - I - - - - - - 1 - 1 170 - 1 - 1 - 3 1 6 190 - 17 - - 4 4 1 4 1 31 210 - 48 1 - 13 - 1 5 16 84 230 2 21 - - 10 - - 5 12 so 250 2 14 3 - 8 - - 4 15 46 270 - 10 - - 3 - 1 1 15 30 290 - 4 1 - 3 - 13 21 310 - 7 1 - - 2 - 20 30 330 - 4 - I - - - 18 23 350 - 4 1 11 16 370 - 4 - 4 8 390 - 1 - 1 2 410 - - 1 - 3 4 Totals 4 135 5 1 40 5 8 24 130 352 !L/Gill net sizes are stretch mesh measurements. Tagged black drum were returned,from June 23, 1979 through May 5, 1983. Of 352 drum tagged, 92 (26.1%) were recaptured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged as high as 41.9%. Information on the number of fish released and recaptured, time at large, and distance traveled are shown in Table 105. Time at large ranged from 4 to 529 days with an average of 141 days. Distance traveled ranged as far as 619 km with an average of 41.2 km. The recovery rate for drum tagged with Howitt tags was 25.2%, and with Floy tags it was 6.0% (Table 106). Recovery rates, when separated into 50 mm length groups, ranged as high as 41.4% with Howitt tags and 9.7% with Floy. Of 36 drum tagged with both tag types, 19 (53%) were recovered. These individuals were at large from 12 to 310 days. Specimens possessing both tag types upon recapture were at large from 21 to 237 days with an average at large time of 164 days. Project personnel using hook and line gear recaptured two drum that bad been single tagged with Floy tags, and only the monofilament line portion of the tag was left protruding from the fish. Thus, movement and growth information was lost on such recap- tures. Increased recovery information would have been available if only Howitt tags had been employed. Furthermore, fishing pressure was obviously greater than was indicated by the observed recovery rate. Comparison of the number of returns by season of release indicated that drum released during the summer months probably had the highest survival rate (Table 10). Recreational fishermen were the major source of black drum recoveries with 67 (72.8%) of the 92 returns. Only 2 (2.2%) returns were from com- mercial fishermen, while study activities accounted for the remaining 23 (25%) recoveries (Table 11). Of 67 recreational recaptures, 48 (72%) provided sufficient information to determine lengths of creel size fish. Lengths (TL) of recreational recaptures ranged from 225 to 461 Mm with an average size of 341 mm (Table 12). Length frequencies of recaptures indicated most creel size drum ranged between 251 and 400 mm with the greatest number of recoveries (73%) occurring between 301 and.400 mm (Table 13). 212 The recovery rate versus the number of specimens released was greatest in the creeks at 63.0% (Table 14). The sounds produced 26.1% of the drum recoveries, the beach accounted for 10.9% and no recaptures were recorded from offshore waters. Return rates were highest during summer and fall (Table 15). Recovery rates for the sound were similar to creeks, but in summer the return rate in the sounds was significantly higher. Winter produced only 8 (8.7%) returns. Georgia residents fishing in state waters accounted for 55 (82%) of the 67 recreational recoveries. Of these resident anglers, 49 (89%) traveled 40 km or less to reach the location of recapture. Approxi- mately 96% of these fishermen traveled less than 80 km (Table 16). The principal bait used by recreational fishermen to catch black drum was shrimp. Approximately 50.6% (40) of all drum recoveries were caught by recreational fishermen using dead shrimp with an additional 36.6% (29) taken on live shrimp (Table 17). Fiddler crabs produced seven (8.9%) returns with a minnow, mussel, and mole crab or "sand flea" accounting for the remaining three (3.9%). Approximately 64% of black drum recoveries were caught in the immediate area of release. Of 92 recoveries, 77 (84%) were caught within 25 km of the tagging site, three (3.3%) moved 26 to 100 km, six (6.5%) moved 101 to 200 km, five (5.5%) traveled 301 to 500 km, and one (1.1%) traveled over 500 km (Table 108). Thirteen percent of all recaptures traveled over 100 km before recapture. Of 14 drum that traveled over 50 km from the release site, 12 had moved soutward, averaging 200 km. These southward moving recaptures were at large 20 to 442 days and re- covered throughout the year with most recoveries occurring during summer and fall. The greatest southward movement (619 km) was by a 310 mm drum at large 185 days and recaptured in offshore waters near West Palm Beach, Florida. Only two drum traveled northward over 50 km, averaging 276 km. These northward migrants were at large from 128 to 455 days and recovered during November and January. Greatest northward movement (437 km) was from a 337, mm specimen at large 455 days and recaptured at the Murrells Inlet jetties, North Carolina. Recaptures indicated 213 Table 108. Days at large and distance traveled for black drum, Pogonias cromis, tagged in Glynn County, Georgia from January 1979 through June 1982. Distance Traveled (km) Days At 51- 101- 201- 301- Over Large 0 0.1-1 1-5 6-25 26-50 100 200 300 500 500 Total Percent 4-1 1- 50 18 1 - - 3 1 - - 24 26.1 51- 100 5 1 4 - - - 1 11 11.9 101 - 150 17 1 3 1 1 1 1 1 26 28.3 151 - 200 7 - 3 - - - - - 11 11.9 201 - 300 7 1 1 - 1 - 10 10.9 301 - 500 5 1 1 1 - 1 10 10.9 Total 59 2 3 13 2 6 2 3 1 92 100.0 Percent 64.1 2.2 3.3 14.0 1.1 2.2 6.5 2.2 3.3 1.1 100.0 that greatest movement was during winter with an average of 159.1 km. Spring and summer recoveries showed the least amount of movement (Table 21). As shown in Table 109, movement in the estuary was limited with 64.1% of the black drum remaining in the general area of tagging. Movement within the estuary was generally toward outside waters as indicated by the number of returns that moved from a creek to beach direction. From the number of recaptures and distances traveled by fish emigrating from the estuary, drum apparently do not exhibit the same tendency to return to a specific estuary as was observed for spotted seatrout. For the most part, movement of drum out of the estuary was southward. As stated earlier, one of the primary objectives for using Floy tags was for obtaining multiple recaptures to increase movement infor- mation. Unfortunately, only three black drum were recaptured a second time. Therefore, multiple recapture information was insufficient to ascertain movement trends. However, during April one black drum multiple recapture showed movement from the creek sector to the sound sector and back to the original release location within a 14 day period; Movement of the other two black drum indicated basically random move- ment within the estuary. Length-Weight Relationship The length-weight relationship for 79 black drum, ranging from 158 to 1,190 mm and 61 to 29,510 g, was log W = 3.075 logL -4.969. The correlation coefficient value for length-weight was 0.9902 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male, female, and all black drum combined are shown in Table 24. Figure 30 illustrates length-weight relationship for black drum. Length-weight relationships calculated for black drum showed iso- metric growth (b = 3.075). Greatest lengths recorded were 492 mm for males and 1,190 mm for females. The heaviest male weighed 1,885g, and the heaviest female was 29,510 g. However, sex was not determined for 215 Table 109. Seasonal movement of black drum, Pogonias cromis, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved By Recaptured Tagged Fish Length Group Caught In Area Movement Witht;.Eatua Movement Out Of Estuary Season (mm) Of Release Creek to BeacE acE T7creek North South Winter 151-200 - - 201-250 2 1 251-300 2 1 301-350 - 1 351-400 1 401-450 - - Total 4 4 Percent. 50.0 50.0 Spring 151-200 1 - 201-250 6 1 251-300 3 1 301-350 - 1 351-400 401-450 - - (ON Total 10 2 3 Percent 66.7 13.3 20.0 Summer 151-200 3 - - 1 201-250 11 2 - 1 251-300 5 1 - I - 301-350 5 2 - 1 2 351-400 - - 1 401-450 - - Total 24 2 5 Percent 66.7 13.9 5.5 13.9 Fall 151-200 4 1 201-250 4 1 251-300 5 1 - - 3 301-350 6 - - 2 2 351-400 2 - - - 1 401-450 - - - - 1 Total 21 1 - 2 9 Percent 63.6 3.0 - 6.1 27.3 Combined Total 59 8 - 4 21 Percent 64.1 8.7 - 4.4 22.8 40 35 W= 000011 L3.075 2 n= 79 r 99 30 25 20 15 10 5 15 @O 45 60 75 90 105 120 TOTAL LENGTH (CM) Figure 30. Length-weight relationship of black drum, Pogonias cromis, collected in Glynn County, Georgia from January 1979 through June 1982. 217 one specimen measuring 1,207 mm and 36,774 g. This fish was entered in the state's saltwater fishing records program. The weights of Georgia drum are compared with fish from other areas in Table 110. In general, Georgia drum were heavier at length than reported for fish from Dela- ware (Thomas, 1971). Texas (Marcello and Strawn, 1972), Virginia (Richards, 1973), and Louisiana (Hein, Dugas, and Shepard, 1980). Age and Growth Age and growth studies based on length frequencies of black drum have been conducted by Pearson (1929), Simmons and Breuer (1962), and Richards (1973). Pearson (1929) and Richards (1973) also investigated the use of scales for ageing black drum. In general, length frequencies were useful only for the first several years of life, and alternative ageing methods must often be employed for older fish. .Difficulty in ageing black drum occurred when attempting to age individuals older than four or five years of age. The difficulties were compounded by increased calcification or thickening of the scales, nar- rowing of increments, and formation of more than one annulus-like mark per year in older fish. According to Richards (1973), the formation of two rings per year probably does not begin precisely in the fourth year, but may occur earlier with some individuals. Scales and otolith sections from 86 black drum ranging from 158 to 1,207 mm were examined, and scales from 76 (88%) were considered legible for age determinations. Of these 76 specimens, 72 (95%) were less than 493 mm in length. Scales and otoliths proved useful for individuals less than 500 mm, but disconformities made scales impossible to read and thus unreliable as an ageing structure for larger specimens. Calculation of mean monthly growth from marginal increments in- dicated that scale annuli of young black drum form during February, March, and April. However, insufficient collections of older drum prevented the validation of time of ring formation or number of rings formed per year. In an effort to validate the number of annuli being laid down each year, scale samples from five recaptured black drum were compared with samples taken at the time of release. Unfortunately, 218 Table 110. Comparison of total length-weight relationships for several populations of black drum, Pogonias ormi8. Length - Weight - Weight f Fish (g) Study Location Equation 350 mm 500 mm 750 um I/ Thomas (1971) Delaware log W - 3.241 logL -5.3234- 425 1,348 5,004 2 Marcello and Strawn Texas log W - 3.165 logL -4.981-1/ 612 (1972) Richards (1973) Virginia log W - 3.066 logL -4.90 3 667 1,990 6,900 Hein, Dugas, and Louis iana log W - 2.971 logL -4.818 550 1,587 5,292 Shepard (1980) Present Study Georgia log W - 3.075 logL -4.969 712 2,132 7,416 -!/Equation based on standard length (mm). !/Equation based on standard length of specimens less than 301 mm. I/Equation based on total length (cm) and total weight (kg). NOTE: Standard lengths converted to total lengths using the formula TL - 1.23 SL. maximum time at large for these fish was 126 days and none of these possessed additional annuli. Linear regression analyses of the relationship between fish length and scale radius were performed. The r 2 value of 0.93 (P < 0.0001) sug- gests the relationship was sufficiently linear to warrant the application of direct proportion calculations to determine length at time of annulus formation. The empirical and mean back-calculated lengths at age for black drum are shown in Table 111. Table 112 shows the empirical and weighted mean back-calculated lengths for juvenile, male, female, and combined black drum. Figure 31 illustrates the length-age relationship for sexes combined, and Table 29 presents the length-age equations for young black drum. Based on length frequency data, Pearson (1929) reported a modal- length of approximately 250 mm by the end of the first year and 370 mm by the end of the second year for Texas black drum. Simmons and Breuer (1962) reported that a standard length of 140-180 mm (167-214 mm TL)-!' was reached in one year and 290-330 mm (345-39.3 mm TQ for two year old Texas drum. Richa rds (1973) back-calculated the lengths of 272 Virginia drum and determined mean lengths to be 195, 396, 554, and 669 mm for the first four scale@rings, respectively. Georgia drum of similar age ex- hibited mean lengths of 198, 336, 440, and 538 mm, respectively. Un- fortunately, at-large time for black drum r'ecaptures was not sufficient to document and validate growth rate. Only one tagged drum was at large for approximately one year (352 days). This fish measured 195 mm when tagged and grew to 380 mm, a growth increase of 185 mm. In general, the lengths of black drum reported from Texas 4nd Virginia were similar to those for Georgia. However, black drum from Virginia waters appear to attain greater lengths for each successive scale ring. Determination of age using the scale technique became increasingly more difficult and unreliable for drum larger than 500 mm. Table 113 lists the lengths and otolith ring counts of all black drum over 400 mm. I/ Converted from standard length to total length using the conversion equation TL = 1.1956. 220 MW Table Ill. Mean back-calculated total lengths for black drum. Pogonias cromis, collec ted in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Ring Length Range Mean Length Mean Back-Calculated Lengths of Successive Scale Rings class Number at Capture at Capture 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0 37 158 - 270 212 1 24 205 - 424 287 213 2 6 343 - 461 393 172 345 3 1 447 447 220 3" 445 4 3 464 - 582 513 153 311 422 506 6 1 733 733 176 327 MO 601 659 723 14 2 893 - 918 905 170 337 430 554 608 632 666 716 763 809 832 859 883 900 WIShod Me=s 1" 336 440 539 625 662 666 716 763 809 832 859 883 900 Growth Iscremats 1" 138 104 87 37 4 50 47 46 23 27 24 17 SM: LevStha measured in millimeters. Table 112. Number, empirical and back-calculated total lengths, and growth increments by sex and age for black drum, Pogonias cromis, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Scale Ring Class Sex 2 3 4 5 6 7 8 9 10 11 12 13 14 Juveniles Number 9 2 Mean Length at Capture 305 379 Back-Calculated Length 219 346 Growth Increment 219 127 Nales Number 10 2 1 1 Mean Length at Capture 274 402 447 492 Back-Calculated Length 188 332 423 490 Growth Increment 188 144 91 67 Females Number 5. 2 0 2 0 1 0 0 0 0 0 0 0 2 Mean Length at Capture 282 397 523 733 905 Back-Calculated Length 192 340 455 547 625 662 666 716 763 809 832 859 883 900 Growth Increment 192 148 115 92 78 37 4 50 47 46 23 27 24 17 Combined Number 24 6 1 3 0 1 0 0 0 0 0 0 .0 2 Nean Length at Capture 287 393 447 513 733 905 Back-Calculated Length 198 336 440 538 625 662 666 716 763 809 832 859 883 900 Growth Increment 198 138 104 98 87 37 4 50 47 46 23 27 24 17 NOTE: Lengths measured in millimeters. d1k 400-- 350-- 300 250-- Ld 200 0 150 A= .000069 L1 771 2 100 n= 81 r 87 50 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 AGE (YEAR) Figure 31. Length-age relationship of black drum, Pogonias cromis, collected in Glynn County, Georgia. 223 Table 113. Total lengths and number of otolith rings for all black drum greater than 400 on. Total Length Number of Total Length Number of (mm) Otolith Rings (mm) Otolith Rings 420 2 893 14 424 2 018 14 425 2 947 12 447 3 1,124 44 461 2 1,132 46 464 4 1,146 43 492 4 1,183 30 560 3 1,190 37 582 4 1,207 34 733 6 40 As stated earlier, Richards (1973) reported that two rings are probably formed each year after the fourth year. Based on his findings, a drum exhibiting 46 otolith rings would be approximately 25 years old. How- ever, Rohr (1980) reported the additional rings on red drum otoliths may consist of summer and winter annuli and spawning checks. Such find- ings could possibly be applicable to black drum. If three rings are formed each year after maturity, the 1,132 mm drum would be approxi- mately 18 years old. However, it should be noted that several investi- gations using various methods, including the uranium decay series nuclides 226 Ra and 21 OPb to establish the periodic nature of growth-zones in oto- liths, have estimated the maximum age of some species of the genus Sebastes to be 80 to 140 years (Bennett, Boehlert and Turekian, 1982; Chitton and Beamish, 1982). Although the number of otolith rings that black drum form annually are questionab le, it is not totally unreasonable for drum to reach 46 years of age. In general, the first 4 to 5 scale and otolith ring classes were considered reliable for estimation of age (Table 112). How- ever, greater ring classes were not reliable and until the number of rings formed annually by older drum can be documented, only estimations of age can be made (Figure 32). Further investigation should be conducted in this area. Maturity and Spawning During this study the smallest specimens collected for which sex was determined through gross examination was a 200 mm (age 0) female and a 187 mm (age 0) male. The smallest female exhibiting developing ovaries was a 582 mm (age IV) specimen. No males exhibiting advanced development were collected, but one stage II specimen 947 mm in length was observed. It is expected that much smaller reproductive males probably occur, but we failed to collect them. Once drum are sexually mature they are reported to spawn annually until death (Pearson, 1929). In south Carolina they have been reported to reach sexual maturity at the end of their second year at a length of 14-16 inches with spawning from February through May in offshore waters and at inlets to sounds 225 LENGTH-OTOLITH RING RELRTIONSHIP 1200 x -meow x x x 1050 900 750 - 600 - z 9 x 450 x x 300 x C E-4 150 6 12 18 24 30 36 42 48 NUMBER OF RINGS Figure 32. Empirical length/otolith ring relationship for black drum, Pogonias cromis, collected in Glynn County, Georgia. and rivers (Lunz, 1955). Frisbie (1961) reported spawning in offshore waters of mid-Atlantic from March to May in the Chesapeake Bay and Delaware Bay at the northern limits of the effective spawning range. Simmons and Breuer (1962) reported spawning in all the bays and over any type bottom as well as in the Gulf near passes. They reported that spawning takes place in February and March, but there is a prolonged or split season in May or June. Richards (1973) reported that the adults concentrate in Virginia waters during spring and early summer for spawning. Ripe adults were encountered from April through mid-June and then the adults apparently dispersed throughout Chesapeake Bay after spawning. Silverman (1979) reported that black drum became sexually mature by the end of the second year when approximately 285-330 mm, and that spawning takes place primarily in ocean waters and in bays with peak spawning during May. Ross, Ravela and Cbittenden (1983) suggested offshore spawning in the Gulf due to the occurrence of well developed gonads in March and April. Most of the black drum collected during this study were under age II -- the age at which maturity is reached (Lunz. 1.955; Silverman, 1979). The maturity stages of the 43 drum for which sex was determined are pre- sented by month, sex, and reproductive stage in Table 114. Spawning apparently took place primarily during March and April as advanced maturity was encountered only during these months. However, spawning activity probably took place from March through May even though large specimens in spawning condition were not collected. Females exhibiting advanced ovarian development were collected in April and May in salinities ranging from 21 to 25 0 oo, and spent fe- males were taken in May from salinities >26 0/oo (Table 115). Advanced "prespawn" and ripe females were collected at temperatures ranging from 16 to 250C, but at temperatures above 260C, only spent females were found (Table 116). Although only four advanced maturity stages were collected, spawn- ing activities appeared to be centered around full moon as the two pre- spawners (stage V and VI) were collected during the three day period 227 Table 114. Number of black drum, Pogonias CrOmis, collected by month, sex and reproduction stage for the period January 1979 through June 1982. ReRroductive Stage II III IV V VI VII Month F M F M F M F M F M F M F M January 2 6 February 0 3 March 2 13 April 3 1 0 1 1 .0 May 2 1 1 0 2 0 June 0 1 July August- 1 0 September 1 1 October November 0 1 December Ak Table I IS. Stages of gonadal developsent for black drum. P(,U. niaa bv month, se x and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Saljnity (0/00, Repr@u tive 0-5 61-10 11@15 16-20 21_2@ 1130 31-35 36@40 Total@ F M F F M F M F M ftn@t 1, S X: F January 1 1 5 1 0 0 1 6 II-Vil - - - - - - - February 1 0 1 1) 3 I]-VIl March 1 1 8 0 1 1 2 2 13 LI-VIl - - - - - - - - April 1 2 0 3 1 IV V Vi 0 V11 - May 1 0 1 0 0 1 2 1 PQ IV V 1 0 1 0 V1 - - Vil 2 0 2 0 June 1 0 1 0 1 II-Vil July I-Vil Aug" t I 1 0 1 0 Il-VIl September I Il-VII October I-VII November I - - - - - - - - - - 0 1 0 1 II-Vil December I-Vil Combined 1 1 8 0 2 2 7 4 3 1 5 3 2 11 27 Total 11 0 1 0 1 III IV V 0 1 0 V1 0 1 0 Vil 2 1 0 Table 116. Stages of gonadal development for black drum, Pogonias cyvmia. by water temperature and sa linity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982.,., Surface Water Temperature ( 0C) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Tot;Is (0/00) Stake F M 7 M 0-5 0 0 1 II-Vil - - - - 1 1 8 1 8 6-10 11 - - 0 1 0 1 III-VII 0 2 0 2 1 7 1 0 .2 7 16-20 IV V VI VII 0 I 1 0 1 2 1 0 1 1 4 3 21-25 IV V 1 0 '1 0 VI 1 0 1 0 VII 1 0 1 0 1 0 1 1 1 1 4 26-30 II-VI - - - - - - - - - - VII - - 2 0 2 0 31-35 1 3 2 - - 3 2 II-VII - - - - - - 1 1 8 2 9 1 5 5 3 2 2 .11 27 TOTALS IV V 1 0 1 0 VI 1 0 -1 0 VIT 2 0 2 0 t I prior to full moon, whereas the two spent females were collected three days prior to new moon (Tab'le'40). The overall ratio of females to males was 1:1.5 (Table 41). Males outnumbered females in the smaller specimens. However, for specimens 251-500 mm the sex ratio was equal, and in specimens over 500 mm no males were collected. The number and percent of females versus males by salinity gradient are presented in Table 39. No distinct segregation of sexes by salinity was discernable except at a low salinity of 6 to 10 O/oo when nine of the 1-0 specimens collected were males. This may not be significant, since most of the specimens collected during the study were small indi- viduals. There appears to be a general lack of detailed information on black drum fecundity. Pearson (1929) estimated fecundity to be approximately 5,976,000 eggs for a 110 cm Texas black drum. Fecundity was estimated to be approximately 11,398,000 eggs for a 918 mm Georgia black drum. The total weight of this specimen was 20,771 g with the gonads making up approximately 43% (8,863 g) of the fish weight (Figure 33). This specimen exhibited 14 otolith rings. I Food Preference and Feeding Habits The black drum is a highly specialized bottom feeder as indicated by the general lack of fish and by the high occurrence of benthic organ- isms such as crabs, mollusks and worms in its regular diet. Table 117 presents the food items found in the stomachs of black drum by fish size in 100 mm length groups. Of 77 stomachs examined, 62 (80.5%) contained food and 15 (19.5%) were empty. In small.drum (<200 mm) the main diet was made up of decapod crusta- ceans, primarily mud crabs,and annelid worms. Mollusks were absent in the stomachs of these small specimens. In specimens 201-400 mm a variety of organisms were ingested, with decapod crustaceans and annelid worms again the top items. However, in this size group mollusks and unidenti- fied fish parts were also observed. Penaeid shrimp were also of some importance. In specimens 400-700 mm, major foods were decap9d crustaceans and 231 ", -M ON ....... ... . ........ . M' I Figure 33. Gravid black drum with ovaries comprising approximately 43% of the body weight. This 918 mm specimen exhibited 14 otolith rings. Table 117. Stomach contents of Black drum, Pogonias cromia, collected in Glynn County, Georgia from January 1979 through June 1982. Lengt Group (mm) Percent Average Food Item 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 Combined Occurrence %Bolus PISCES Pieces (Unidentifiable) 2 2 3.2 25 ARTHROPODA Crustacea (unidentifiable) 5 7 1 13 21.0 32 Alpheus heterochelis 2 1 3 4.8 33 Caprellidae 1 1 1.6 90 Decapoda 4 10 2 3 19 30.6 63 Eurypanopeus depresaus 1 1 1.6 10 Hexopanopeus angustifrons 1 1 1.6 70 Ovalipee ocelZatue I 1 1 3 4.8 40 Palaomonetes ep. 1 1 1.6 10 ftmopeue herbstii 1 1 2 3.2 15 Panaeidae 2 2 3.2 90 Penaeua aetiferue 1 1 1.6 30 Pome I Uma eayana 1 1 1.6 50 Rhithropanopeus harriaii 1 1 1.6 10 Seearma reticulatwn 1 1 2 3.2 55 SquiZZa empusa Uca pugilator Uca pugn= Table 117. (continued) Length Group (m) Percent Average Food Item 101-200 201-300 301-400 401-500 501-600 601-700 701-800 801-900 901-1000 Combined Occurrence %Bolus HOLLUSCA Molluscs (unidentifiable) 2 3 1 1 1 8 12.9 90 Craaeostrea virginica I 1 2 3.2 80 Mercernaria mercenay-ia 1 1 2 3.2 <5 Nassarius vibex 2 1 3 4.8 17 ANNELIDA Eteone op. 1.6 30 Hetezvmwtus filiformis 2 2 3.2 <5 Nereldae 7 7 11.3 26 Nicotea simplex 3 3 3 9 14.5 40 Spionidae 1 2 3 4.8 47 Streblospio benedicti 1 2 3 4.8 7 Tubificidae I 1 1.6 30 PLANT Detritus 2 1 1 4 6.5 33 Spartina altez-nifloy-a 1 3 1 5 8.1 32 BRYOZOA AnguineNa palrwta I 1 1.6 5 INORCANIC MATERIAL 3 8 4 15 24.2 62 ANIMAL TISSUE Animal tissue 1.6 90 Vertebrate bone 1.6 10 Number of stomachs: 77 Number and percent of stomachs containing food: 62 (80.5%) Number and percent of empty stomachs: 15 (19.52) OP) t I t I ti mollusks, and only one specimen had ingested commercial species of penaeid shrimp. In the largest specimens (>700 mm), there was a defi- nite preference for crabs (lady crabs, OvaZipes oceZZatus; mud crabs, Panopeus herbstii; and wharf crabs, Sesarma reticuZatum) and mollusks. Of the stomachs containing food, 30.6% contained unidentified decapod crustaceans in addition to numerous identified species of shrimp and crabs. Annelid worms and mollusks ranged next as food items. Pearson (1929) reported that smaller-sized Texas drum (under 20 cm, or 7.8 in), with less powerful crushing teeth tend to prey on the softer P ,food organisms such as annelid worms and smaller crustaceans. Fish and annelids represented 36 and 32 percent of the food in smaller black drum, respectively. He reported that medium-sized fish consumed larger amounts of mollusks (33%) and crabs and shrimp (28%), and older drum confined their food largely to mollusks (74%) and crabs (16%). Simmons and Breuer (1962) found that the food of very young Texas drum consisted primarily of annelids, small fishes and small crustaceans, while larger drum fed on mollusks and shrimp. Silverman (1979) reported food habits changing with age, with young drum feeding indiscriminately on the most abundant food available. Medium size fish consumed large amounts of mollusks, crabs and shrimp, and older fish confined food largely to mollusks and crabs. Coastal anglers in Georgia have long recognized that commercial blue crabs and clams are excellent baits for large black drum. It is not uncommon to catch large females over 22.7 kg (50 lb) during the spring spawning season in April. Small specimens are generally taken on fiddler crabs and dead shrimp. The 10 most frequently occurring food items ingested by black drum are presented by season and sector in Table 118. Major food items in- gested during the winter months were annelids, primarily polychaetes, and crustaceans. In spring, major food were decapod crustaceans and bivalve mollusks. During summer, decapod crustaceans were the main diet, with Uca pugnax and U. pugiZator being the most commonly ingested species. In fall, they fed mainly on decapod crustaceans although annelids were also eaten. 235 The greatest portion of the drum diet in the creeks was crusta- ceans, although annelid worms were frequently found (Table 118). In the sounds crustaceans, primarily crabs, were the staple food supply, although some annelids and clams (Mercenaria mercenaria) were also eaten. On the beaches the diet appeared to differ somewhat as annelid worms were the staple while decapods ranked low. In offshore waters they ingested primarily white shrimp (Penaeus setiferus) and lady crabs (OvaZipes ocez- latus) although mollusks were also eaten. A seasonal trend in feeding habits can be seen in Table 119. Feed- ing activity was greatest during the warmer months as over 90% of the stomachs contained food from spring through fall. A reduction in food. consumption was evident for specimens collected during the winter as only 48% of the stomachs contained food. Feeding activity @as apparently similar in the creeks and sounds, with 77.1 and 80.0% of the stomachs containing food, respectively (Table 119). Although low numbers were collected from the beaches and offshore waters, all stomachs examined from these sectors contained food. Water temperature appears to have had some effect on the feeding activity of black drum (Table 50). Feeding activity apparently increased with increase in water temperature. At water temperature below 15 0 C only 43.5% of the stomachs examined contained food. At temperatures 16 to 250C all stomachs examined contained food, while at temperatures 26 to 300C the value dropped slightly to 93.7%. The effects of lunar phases on feeding activity appear to be most pronounced during periods of dark nights as over 93.3% of the stomachs examined contained food during the three day period before new moon and during the first quarter moon phases (Table 51). However, due to the low number of specimens collected further deductions should not be attempted. SHEEPSHEAD Sheepshead (Archosargus probatocephaZus) are geographically distri- buted along the Atlantic coast from Nova Scotia to south Florida and in the Gulf of Mexico (Fischer, 1978). 236 @, I @ I k I I p lp a w w Table 118. The 10 war frequently occurriag food Itema, found in the stonachm of black drum. AV@i,w bv season and s,,t,,r f- fish c.1 1.ctd in Glynn Cognty, Cnorgia from Jammary 1979 thr-gh Jur@ 1982. Vista, In. Perc;@t -A@raze SwIm S- no. Percent Averag, - Per"" A-rag@ Sact" Food Itam St-A. Occurremce, I Dolus F-d Itew St-h. Occurrence I B.I.., Food I,- h. ).c u_-- Z Sol- Cr--k- Nereid- 4 .4 45 Unidentified material 2 28.6 90 Decapoda 4 W.0 38 3 33.3 90 D-pd 2 28.6 75 Annalida 3 37.5 47 Ual tified -t.ri.1 3 33.3 77 Crus= 2 28.6 5 uca pugilu@, 1 25.0 60 Alpha- p. 1 11.1 90 P-ld- 1 14.3 90 g- 2 25.0 60 III ali. I II.1 50 C@assost- 1 14.3 80 f-- - , 1 12.S 90 ph=gea P. 1 11-1 10 pl- II- -y- I I'-' 50 rjuill@ T- 1 12.5 70 Crastecam 1 .1.1 1 Pi-- I 13 40 UvLde- tifted naterial 1 12.5 30 T.bllicidae I 13 30 P-"- P. 1 12.5 10 @ ti-h@uo 1 14'3 20 spartf- al-ifl- 1 12.5 10 A-lid. 1 14.3 10 Rhiti-T."'t- 1 12.5 10 So.." 0.16mtifid material 2 ".7 100 Dcpd. 4 36.4 83 Crixstacea a 72.7 37 L-14- 1 33 3 so L@,@ 3 27.3 so Annelid. 3 27.3 40 stoons, op. 1 33:3 30 4-tima, at temirl- 3 27.3 so Decopda 2 2 90 A-mi" vibcr 3 27.3 17 U- P.J- 2 st-bl.epio bosAKIti 1 33 3 20 1 2 90 1kmas,.-ia ak,_-_,q,@ 2 2 @5 -'c 2 182 60 Animl tiamme I I": O'S M"mmt.r 1 9*1 90 I go U.Ldeat ad 111-1via 1 99: 1 90 1 9.1 10 Molluscs I 1 90 ci-st- 1 9 so Vertebrats (bame) 1 9:1 10 Damcbm mm Spionidne 2 50 45 - liereld- 2 50:.0 20 Xdiawas . P. 2 so .0 @5 Stmbl-pio b-dieti 2 so 5 Ow-p-da I 2S:O. @15 Annalida 1 25.0 3 ,;P-ti- Ita-iflo- 1 25 0 40 Unidentified material 1 25:0 5 Off S.W 3 100.0 40 Am - Blv.lvia 3 100 '0 10 Decap"m 2 66.7 is Crust- 1 33.3 30 pv@ma -,tif, 1 33.3 30 L'h,lipca - 11atw 1 33 3 20 Unidentified material 1 33:3 20 110W. US16natifted notarial 5 41.7 52 D--P-" 3b 0 57 Crust-ea 421 36 Mareld" 4 33 3 45 Dival, . 24:0 33 D-pad. 86 3 55 0 90 Unidentified material 5 20.0 42 A-lid. 6 3 25: 311. 43 Alpha- p. 1 90 sp-tima Iw-iftora 4 .0 39 u- Pw@ 4 21.1 71 1 ::,3 50 Sepamma i-- 3 1162.0 so Unidentified material 2 10.5 (10 1-1dwe 1 3 so &and 3 12 0 40 Plant material 2 10.5 60 mtowme p . 1 3 30 Otalipas coallatias 3 12:0 40 um pwgilator 2 10 5 60 Stmbtmpio banediati I a zo mancM Vibl- 3 12.0 17 S- -tioulatun 1 5:3 .P. .:3 Fin lawmans tas 1 3 10 C-t-- 3 12 0 10 sqill. amp 1 5 70 Crvatacem 1 8.3 @5 *.r.id- 3 12:0 @5 pd.T.- p"" 1 5:3 30 -VOPOn daWst" an -P-CInaQN aera colletted nitb food I. t-ch.. Table 118. (cuntinued) Fall Combined Ttals No. Percent A;i@r-age NO. --'ie -r. @n-t Average Sec-t-or Food I ten Stomachs occurrence Z Bolus Food I tem Stomachs Occurrence Z Bolus Creeks Pemseidae 1 33.3 90 D.-pda 9 33.3 63 Annelids 1 33.3 90 Unidentified material 6 22.2 73 Hcxaj@mopeus anguatifropw 1 33.3 70 Annelids 5 18.5 48 Uca Pugpk= 1 33.3 30 Vereldae 5 18.5 36 Alpheue sp. 1 33.3 10 Uca pu.,nwx 3 11.1 so Crustacea 3 11.1 <5 Pensetdae 2 7.4 90 uca pugilat@r 2 7.4 60 Seaay-w reti,@Iatum 2 7.4 55 Alphcua up. 2 7.4 50 Sounds Crustocea 1 33.3 90 Crustacen 9 32.1 42 Decapods 1 33.3 90 Decapods 7 25.0 86 Caprellidae 1 33.3 90 Unidentified material 4 14.3 70 Organic material 1 33.3 10 Plant material 4 14.3 33 SeBay." ci@^.Zn 3 10.7 so f,@-arti@ a1t,m:ifL.,A, 3 10.7 so Annelids 3 10.7 40 Kwaariua aibex 3 to.7 17 U-- puq-- 2 7.1 90 momemly-ia 2 7.1 <5 leaches mm Spimidae 2 50.0 45 N Hereldae 2 50.0 20 LI) Wdi,@tua sp. 2 SO.0 <5 0.) Stmbl@opio bew,dicti 2 50.0 's Decapoda 1 Z5.0 @s Annelids I 2S.0 <5 sr@xrtiw alt'rniflord 1 25.0 40 Unidentified material 1 25.0 5 Offshore NOW ;and 3 too.0 40 Alwalvia 3 100.0 10 Decapoda 2 66.7 15 Crustacen 1 33.3 30 P,w,uo actifema 1 33.3 30 ovalipes om-llatuo 1 33.3 20 Unidentified Material 1 33.3 20 Total@ Crustacen 1 16.7 90 Decapoda 19 30.6 63 Pensaidae, 1 16.7 90 Crustacea 13 21.0 32 Decapods 1 16.7 90 Unidentified material 12 19.4 62 coprellidoe 1 16.7 90 Annelids 9 14.5 40 Annelids 1 16.7 90 Blvalvia 7 11.3 36 H0xapWWPeu0 WVustifrona 1 16.7 70 Vereidae 7 11.3 26 Uca pugnax 1 16.7 30 U- Pug- 5 8.1 66 Alpheue sp. 1 16.7 10 Soartina alterniflnra 5 6.1 32 plant material 1 16.7 to plant material 4 6.5 33 Svear9w L@incpzan 3 4.8 so LED" denotes so specimens were collected with food In stomachs. or @' I k I k 1 4 P 4P 0 a 0 Table 119. Number and percent of black drum, Pogoniaa cronde, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Total- Food Empty Tot=a Food Epp ty Total No. No. z NO. 2 No. z No. % lw-.% No. % No. % No. % Winter 9 56.3 7 43.7 16 100.0 3 33.3 6 66.7 9 100.0 - - - - - Spring 7 100.0 0 0.0 7 100.0 11 ioo.o o 0.0 11 100.0 4 100.0 0 0.0 4 100.0 Summer 8 88.9- 1 11.1 9 100L. 0 11 91.7 1 8.3 12 100.0 - - - - - Fall 3 100.0 0 4J.0 3 100.0 3 100.0 0 0.0 3 100.0 - - Total 27 77.1 8 22.9 35 100.0 28 80.0 7 20.0 35 100.0 4 100.0 a 0.0 4 100.0 Offshore Combined Sectors Food Empty Total Food Empty Total No. No. NO. z NO. z No. NO. % Winter - - - - 12 48.0 13 52.0 25 100.0 Spring 3 100.0 0 0.0 3 100.0 25 100.0 0 0.0 25 100.0 Summer - - - - - - 19 90.5 2 9.5 21 100.0 Fall - - - - - - 6 100.0 0 0.0 6 100.0 Total 3 100.0 0 0.0 3 100.0 62 80.5 15 19.5 77 100.0 This species uses its large, strong teeth to pick, gnaw, and scrape oysters, barnacles, crabs and clams off submerged pilings and rocks. Hence, concentrations of sheepshead are found near oyster reefs, piers, docks, jetties, bridges and over other areas where shellfish are plenti- ful. In general, larger sheepshead move to offshore live bottom and reef areas during the colder months and remain in offshore waters through the spring spawning season with many returning to the lower estuarine areas in late spring and summer. Juveniles are abundant throughout the estuarine areas during the warmer months but generally move to either the higher salinity areas or to deep water where they are less available for col- lection during the colder months. Movement and Migration From May 23, 1979 through June 22, 1982, 416 sbeepshead were tagged and released. Length frequencies of tagged sheepshead in 50 mm length groups are pr6sented-in Table 120. Lengths (TL) of sbeepshead tagged with Howitt tags ranged from 130 to 540 mm, and those tagged with Floy tags ranged 140 to 530 mm. Length frequencies of sheepshead tagged with each tag type are presented in Table 121. Of 416 sheepsbead tagged, only one fish was tagged with both tag types. Table 122 lists the length frequencies of tagged sheepshead in 20 mm groups by gear type used for recapture. Tagged sheepshead were returned from September 11, 1979 through September 12, 1982. Of 416 fish tagged, 30 (7.2%) were recaptured and tags returned. Recovery rates, for fish separated into 50 mm length groups, ranged as high as 22.2%. The number of sheepshead released and recaptured, time at large, and distance traveled are shown in Table 120, Time at large ranged from 5 to 739 days, averaging 240 days. Distance traveled ranged as faras 98 km, averaging 8.1'km. Recovery rates were 8.2% with Howitt tags and only 1.6% with Floy tags (Table 121). Recovery rates for sheepshead separated into 50 mm length groups ranged as high as 25.0% with Howitt tags and 5.3% with Floy tags. The one sbeepshead tagged with both tag types was not re- turned. 240 w qw Table 120. Number tagged, number and percent recaptured, days at large and distance traveled for sheepshead, Archosay@qus probatocephaZus, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (km Length Group Tagged Recaptured Returned Avg., Max. Avg. Max. 101 - 150 15 0 0.0 151 - 200 38 2 5.3 212 375 7.6 12 201 - 250 134 11 8.2 264 684 7.2 30 251 - 300 138 10 7.2 260 557 13.7 98 301 - 350 53 3 5.7 84 223 0.2 1 351 - 400 18 1 5.6 243 243 6.5 7 401 - 450 9 2 22.2 14 22 0.5 1 451 - 500 7 1 14.3 739 739 3.7 4 501 - 550 4 0 0.0 Total 416 30 7.2 240 739 8.1 98 l/ Distance measured in kilometers from point of release to point of recapture. Table 121. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for sheepshead, Archosargus probatocephalus, tagged in Glynn County,Georgia, from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numbir Number Percent (mm) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 125 9 6 15 175 19 1 5.3 19 1 5.3 38 2 5.3 225 115 11 9.6 19 134 11 8.2 275 124 10 8.1 14 138 10 7.2 325 51 3 5.9 2 53 3 5.7 375 18 1 5.6 18 1 5.6 425 8 2 25.0 1 9 2 22.2 475 7 1 14.3 7 .1 14.3 525 3 3 Total 354 29 8.2 61 1 1.6 415 30 7.2 NOTE: Number tagged and recaptured does not include the one fish tagged with both tag types. i@ I @ I ( I k I I P q P I P RP Table 122. Number of sheepshead, Archoeargua probatocephalus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length l/ Group Gill Net (in)-!@ Trammel Cast (mm@ 2-718 3-1/2 4-5/8 6 8-1/2 Net Trawl Net Trap Hook/Line Totals 130 - - - - - - - 5 - 5 150 - 1 5 12 1 19 170 - 1 - 4 10 4 19 190 - - 3 2 5 10 210 1 - - 4 2 21 28 230 1 1 2 2 3 55 64 250 1 - - - 3 2 4 77 87 41 270 1 - - - 1 - 1 4 40 47 290 5 - - - 2 - 1 4 34 46 310 2 - - - 2 - - 1 24 29 330 4 - - - 2 - - - 12 18 350 - - - - - 10 10 370 2 1 - - - 5 9 390 1 1 - - - 3 5 410 2 1 - - - - 1 4 430 1 - 1 1 - - 2 5 450 - I - - - 1 2 470 1 - - - - - - 2 490 2 - - - - - - 3 510 1 - - - - - - 1 530 2 - - 1 - - - 3 Totals 27 1 3 1 1 16 3 22 47 295 416 YGill net sizes are stretch mesh measurements. Recreational fishermen were the major source of sheepshead re- coveries, accounting for 23 (76.7%) of 30 returns. Study activities accounted for 7 (23.3%) recoveries, while commercial fishermen failed to return any recaptures (Table 11). Of 23 recreational recaptures, 15 (65%) included sufficient information to determine lengths of creel size fish. Lengths (TL) of recreational recaptures for sheepshead ranged from 192 to 393 mm with an average size of 300 mm (Table 12). Length frequencies of recaptures indicated that most creel size fish were over 250 mm (Table 13). Of 30 recoveries 29 specimens produced sufficient information to determine the sector and season of recapture. The creeks produced the highest return rate of 62.1% (Table 14). However, the recovery rate in the sounds was proportionally higher than the number released in this sector, indicating higher fishing pressure. Spring produced most of the recoveries (37.9%) while none were recaptured during winter (Table 15). Georgia residents fishing in state waters accounted for 21 (70%) of the 30 recreational recaptures. Of these resident anglers, 18 (86%) traveled 40 km or less to reach the location of recapture, while approxi- mately 95% traveled less than 120 km (Table 16). Fiddler crabs were the principal bait used by recreational fisher- men to catch sheepshead (Table 17). Approximately 74% of all recreational recoveries were on fiddlers, and the remaining recoveries were caught with live and dead shrimp (17 and 8 percent, respectively). Approximately 37% of the sheepshead recoveries were caught in the immediate area of release, with 28 (93%) captured within 25 km of the release site (Table 123). Only two recoveries traveled more than 25 km. These fish were at large 557 and 684 days and traveled southward 98 and 30 km, respectively. Spring was the season of greatest movement with fish moving an average distance of 17.9 km prior to recapture (Table 21). Winter recaptures exhibited the least movement with average and maximum distances of only 1.5 and 4.4 km, respectively. Although recovery data indicate most sheepshead do not migrate great distances, the species appears to exhibit random-movement within 244 Table 123. Days at large and distance traveled for sheepshead, Archosargus probatocephalus, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At Distance traveled (km) Large 0 0.1-1 1-5 6-25 26-50 51-100 Total Percent 1 - 50 5 1 2 1 - - 9 30.0 51 - 100 2 - - I - - 3 10.0 101 - 150 - - - - - - 151 - 200 - - - - - - - - 201 - 300 1 1 1 2 - - 5 16.7 301 - 500 3 - 3 4 - - 10 33.3 501 - 750 - - 1 - 1 1 3 10.0 Total 11 2 7 8 1 1 30 100.0 Percent 36.7 6.7 23.3 26.7 3.3 3.3 100.0 the estuarine system. Recovery data were insufficient to determine seasonal movement trends within the estuary (Table 124). When sheeps- head did emigrate out of the estuary, they generally moved near off- .shore reefs, with some tendency to move southward. Length-Weight Relationship The length-weight relationship for 118 sheepshea.d, ranging from 101 to 591 mm (TL) and 21 to 4,297 g, was log W = 2.885 logL -4.412. The correlation coefficient value for length-weight was 0.9707 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male and female, and all sheepshead combined are pre- sented in Table 24. Figure 34 illustrates length-weight relationship for sheepshead. The greatest lengths recorded were 563 mm for males and 591 mm for females. The heaviest male and female were 2,962 and 4,297 g, respectively. Age and Growth Although sciaenids have received extensive research on the Atlantic and Gulf coasts, comparatively limited work has been published for sheepshead. Published information pertaining to age and growth was limited. Scales from 118 sheepshead ranging from 101 to 591 mm were examined and scales from 105 (88%) were determined to be usable for age analyses. Otoliths from 105 specimens were also examined to document the validity of annuli counts ascertained from scales. Annuli formation on the anterior portion of sheepshead scales appear as abrupt, irregular changes or breaks in the circuli patterns. Also, new circuli cutting over the incomplete circuli in the lateral areas of the scales were identified as annuli. Calculation of mean monthly growth of marginal increments of sheeps- bead less than five years old validated that scale annuli were formed only once annually. A single annulus formation was detectable on young sheepshead scales during February and March, with all scales bearing recent annuli by early April. Calculations indicated similar findings 246 Table 124. Seasonal movement of sheepshead, ArchosarVue probatocephalua, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved By Recaptured Tagged Fish Length Group Caught In Area Movement Within Estuary ---V Movement Out Of Estuary Season (M) Of Release Creek to Beach Beach To Cree North South Winter No Recaptures Spring 151-200 - - 1 201-250 1 2 251-300 - 2 1 301-350 1 - - 351-400 - 1 - 40i-450 - - 451-500 - - - Total 2 5 1 1 2 Percent 18.2 45.4 9.1 9.1 18.2 Summer 151-200 - - - - - 201-250 2 3 251-300 1 1 - 301-350 1 - - - - 351-400 - - - - - 401-450 - - - - - 451-500 - - - - - Total 4 1 - - 3 Percent 50.0 12.5 - - 37.5 Fall 151-200 - - 1 201-250 1 - 1 251-300 2 - 1 2 301-350 - - - - 351-400 401-450 1 451-500 - I - Total 3 1 1 5 Percent 30.0 10.0 10.0 50.0 Combined Total: 9 7 2 1 110 Percent 31.1 24.1 6.9 3.4 34.5 4.8-- 4.2-- W= .000039 L2.885 2 n= 118 r 97 3.6-- 3 2.4-- Uj 0.6-- 7.5 15 22.5 30 37.5 45 52.5 60 TOTAL LENGTH (CM) Figure 34. Length-weight relationship of sheepshead, Archosargus probatocephaZus, collected in Glynn County, Georgia from January 1979 through June 1982. 248 for older specimens, but approximately 90% of all fish over four years old were collected during April, May, and June. Therefore, documentation of time of annulus formation and number of annuli formed each year by older fish was limited. Least-squares regression analyses on the relationship between fish length and scale radius were performed. The correlation coefficient value of 0.89 (P < 0.0001) suggests the relationship was sufficiently linear to warrant direct proportion calculations to determine fish length at time of annulus formation. The empirical and mean back-calcu- lated total lengths at age for sheepshead are presented in Table 125. Figure 35 illustrates length-age relationships,and Table 126 shows the empirical and weighted mean back-calculated lengths for juvenile, male, female, and all sheepshead combined. Length-age equations for sheeps- head are shown in Table 27. To document estimates of growth obtained from back-calculations, growth rates of five tagged specimens at large from 11 to 13 months were determined. Lengths when tagged ranged 175 - 239 mm and averaged 215 mm, and the mean growth increase was 80.6 mm. The empirical annual growth was slightly less than estimates from back-calcu.1ations. How- ever, agreement between empirical and estimated growth rates from back- calculations were sufficient to document growth rates of sheephead. Maturity and Spawning During the study, the smallest sheepshead examined for which sex could be determined through gross examination was 200 mm for females and 187 mm for males. Both of these fish were age 0 or in their first year of life. The smallest female toshow developing ovaries (stage III or greater) was a 282 mm specimen (age III) while the smallest male was 393 mm (age IV). Growth and development of larval and young have been described by Hildebrand and Cable (1938) and by Mook (1977). How- ever, a review of the available literature showed a general lack of information as to size and age at maturity and spawning for this species. Although sheepshead are found throughout the marine environment in Georgia, spawning activity appears to be centered in offshore waters. 249 Table 125. mean back-calculated total lengths for sheepshead, Archosargus probatocephalua, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Ring Length-Range Mean Length Mean Back-Calculated Lengths of Successive Scale Rings Class Number at Capture at Capture 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0 10 101 - 181 145 1 20 209 - 286 244 164 2 29 212 - 350 273 154 246 3 8 301 - 399 364 147 256 319 4 11 332 - 465 404 137 254 336 388 5 1 418 418 114 262 345 391 417 6 7 435 - 526 465 146 253 330 378 427 459 CD 7 6 485 - 540 508 147 270 363 411 451 478 501 8 4 473 - 537 512 146 258 328 393 430 465 490 507 9 2 555 - 563 559 142 278 359 417 470 516 531 546 553 10 2 568 - 578 573 136 246 313 364 416 442 484 525 550 561 11 2 493 - 542 518 127 254 310 362 410 442 465 483 492 501 513 12 1 563 563 136 264 307 357 420 459 488 513 531 538 548 557 13 0 14 1 591 591 136 273 369 430 491 520 534 542 552 558 -569 575 582 588 Weighted Means 150 253 334 390 436 469 497 516 534 536 536 566 582 588 Growth Increments 150 103 81 56 46 33 28 19 18 2 0 30 16 6 NOTE: Lengths measured in millimeters. 60 52.5-- 45,-- :5_ 37.5-- z W _j 30 _j 0 A= .000043 L 1.953 22.5-- 2 n= 118 r 86 15 7.5 + 2 4 6 8 10 12 14 NUMBER OF RINGS Figure 35. Length-age relationship of sheepshead, Archosargus probatocephalus, collected in Glynn County, Georgia. 251 Table 126. Number, empirical and back-calculated total lengths, and growth increments by sex and age for sheepshead, Archosargus probatocephaZus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Scale Ring_Class Sex 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Juveniles Number 3 6 0 1 Mean Length at Capture 232 277 347 Back Calculated Length 144 240 296 328 Growth Increment 144 .96 56 32 Males Number 8 9 0 5 1 3 1 3 1 0 1 Mean Length at Capture 252 250 412 418 454 516 514 563 493 Back Calculated Length 146 253 342 390 425 459 487 505 507 469 485 Growth Increment 146 107 89 48 35 34 38 18 2 16 U1 Females Number 9 15 8 5 0 4 5 1 1 2 1 1 0 1 Mean Length at Capture 241 285 364 409 480 506 505 555 573 542 563 591 Back Calculated Length 146 256 @332 393 443 474 502 524 541 551 552 566 582 588 Growth Increment 146 110 76 61 50 31 28 22 17 10 1 14 16 6 Combined Number 20 29 8 11 1 7 6 4 2 2 2 1 0 1 Mean Length at Capture 244 273 364 404 418 465 508 512 559 573 518 563 591 Back Calculated Length 150 253 334 390 436 469 497 516 534 536 537 566 582 588 Growth Increment 150 103 81 56 46 33 28 19 18 2 1 30 16 6 NOTE: Lengths measured in millimeters. Ovarian development was first observed in March when one stage III fe- male was found. However, spawning was apparently fully underway in April when advanced maturities (stages IV through VI) were collected in numbers (Table 127). All of these spawners were collected in April at artificial reef "WR2" approximately 13 nautical miles offshore from Cumberland Island, Georgia. These 22 adults were collected by speargun in water approximately 16 meters (50 ft) deep over artificial reef habitat consisting of sunken automobile tires and an old steel ship from World War II and over otherwise barren sand bottoms. Adult sheepshead are commonly taken by recreational anglers on nine of Georgia's artificial reefs as well as on the natural live bottom area known as Cray's Reef National Marine Sanctuary approximately 16 nautical miles offshore from Sapelo Island. Consequently, spawning pro- bably takes'place at each site during early spring. Spawning at in- shore areas was not encoUntered during our sampling, but one recreational sheepshead angler reported taking sheepshead,,with advanced ovarian de- velopment in Dupelin River behind Sapelo Island in April 1983 (Mr. Ernest Robarts, personnel communication). Since all advanced stages of maturity were collected from offshore waters in April, it is assumed that this is when and where peak sheeps- head spawning activity is centered. These 22 spawners were collected at salinities of 36 0/oo and at temperatures of 21-25 0C (Tables 128 and 129). Our findings agree with results of investigations in other areas that spawning generally takes place in spring from April through June in ocean waters. Rathbun (1892) reported sheepshead spawning along sandy shores in late evening in southwest Florida. Hildebrand and Cable (1938) concluded from the collections of young and one developing roe sheepshead that spawning in the Beaufort, N.C. area was from April through June. McClane (1965) reported that although data were scarce, spawning apparently takes place in the spring. Mook (1977) reported that sheepshead spawn in the spring (April and May) in temperate North Carolina and as early as the first part of March in subtropical southern Florida. 253 .4 'rable 127. Number of sheepshead, Archosargus probatocephalus, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage II III IV V VI Vil Month F M F M F M F M F R T R F M January 2 0 February 5 1 March 2 1 1 0 April 0 2 0 4 10 4 2 0 May 5 9 3 0 lune 7 2 1 1 July 3 1 August 4 1 September 5 2 1 0 October 3 1 November 7 7 December 0 1 A Table 129. Stuges of gonadal development for s"shead, Archoaargue probatooephalwo, by months max and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Reproductive Surface Water 84110ity (0/00 Total@ 44 i Ox If M -?@ -7&-+ M-1kil Stage January 1 2 0 2 0 February 1 0 3 1 1 0 5 1 III-Vil March I 1 0 2 1 1 0 1 0 IV-Vil April I 0 2 0 2 IV 0 4 0 4 V 10 4 10 4 VI 2 P 2 0 may 0 1 1 2 5 9 0 1 0 1 0 3 0 June 6 1 0 1 1 0 7 2 1 0 0 1 III-VII July I 1 0 2 1 3 1 li-VII August 1 2 0 1 1 1 0 4 1 II-VII Sept.mbar 1 1 0 4 2 5 2 11 - - 1 0 1 0 III-VII October 1 2 0 1 0 0 1 3 1 It-VII November 1 6 6 1 1 7 7 11-VII - - - - 0 1 0 1 C.mbin.d 1 4 6 1 19 7 8 6 5 3 1 2 38 24 T.tal 11 1 0 1 U 5 1 2 1 0 1 1 0 10 3 III 1 0 0 2 1 2 IV 0 4 0 4 V 10 4 10 4 VI 2 0 2 0 VII 255 Table 129. Stages of gonadal development for sheepshead, Archosargus probatocephalue, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Temperature ( 0C) Salinity 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Totals (0/00) F M F F N F M F M F R T- M F M, 11-15 1 1 0 3 6 4 6 11 0 1 0 III-VII - 16-20 1 0 0 11 1 0 0 III-VII 21-25 1 2 0 7 6 10 1 19 7 Il- 3 1 2 0 5 1 III-VII - - - - 26-30 1 5 3 1 1 8 6 II 1 0 2 1 C;@ 31-35 1 - - 1 0 4 2 5 2 0 1 0 1 1 0 1 0 IV-VII 36-40 1 1 2 1 2 1 0 1 0 0 2 0 2 IV 0 4 0 4 V 10 4 10 4 VI 2 0 2 0 VI VII Totals 1 2 0 1 0 8 7 6 9 20 6 1 1 38 23 1 0 1 0 4 2 1 0 3 1 0 0 10 3 1 2 1 2 IV 0 4 0 4 V 10 4 10 4 VI 2 0 2 0 Vil Since all advanced maturities were collected at once, no hard facts can be correlated between spawning activity and lunar phases. However, these advanced maturities were collected three days prior to new moon (Table 40). No!other advanced stages were collected because of sample design. Female sheepshead outnumbered males 1.7:1 (Table 41), and dominated catches at all salinity levels except 11-15 0/oo where males comprised 54.5% of 11 specimens sampled (Table 128). A literature review of investigations dealing with sheepshead re- vealed a general lack of information on fecundity for this species in the Gulf of Mexico and Atlantic coast waters. Since offshore waters were beyond the general study area, collections of advanced reproductive maturity stages of sheepshead were limited. Fe- cundity estimates were determined for 12 sheepsbead ranging in length and weight from 428 to 591 mm and 1,647 to 4,297 g, respectively. These 12 specimens exhibited otolith ring counts from 4 to 14. Mean estimated fecundity was 604,559 eggs with a range from 296,000 to 963,000. Fecun- dity data for Georgia sheepshead are presented in Table 130. Food Preference and Feeding Habits Sheepshead are adapted to a grazing type of feeding behavior as they have large crushing type teeth that allow them to eat a variety of hard bodied crustaceans and mollusks that exist on and attach to pilings, rocks, and natural reefs. In Georgia they are most often taken by recreational anglers using fiddler crabs and fishing around pilings under bridges and docks in inland waters and on-man-made reefs in off- shore waters. Table 131 presents the food items ingested by sheepshead by fish size in 100 mm length groups, Of 117 sheepshead stomachs examined, 102 (87.2%) contained food and 15 (12.8%) were empty. There appears to be little difference in food types preferred by different size groups except for a greater inclusion of mollusks, echinoderms and urochordates with increase in size. In smaller specimens (<200 mm) 257 10 Table 130. Estimated fecundity for 12 sheepshead, Archosargus probatocephalus, collected approximately 21 miles southwest of St. Simons Island, Georgia during April, 1982. Ring Number Total Length (mm) Mean Fish Percent Gonad Estimated Fecundity (XIOOO) Class of Fish Mean Range Weight (R) Weight Mean RanRe U1 4-6 4 466 428 - 526 2,091 7.0 489.3 335.1 - 660.6 7-9 5 514 485 - 555 2,740 8.6 648.3 295.6 - 930.6 10-14 3 574 563 - 591 3,769 12.0 795.1 678.7 - 962.6 Combined 12 513 428 - 591 2,780 8.3 604.6 295.6 - 962.6 ti Table 131, Sto"cb contents of Sheepshead, Archoeargus probat@ephalwa, collected in Glynn C@ounty, Georgia frm January 1979 through June 1982. Group (m) Percent Average Food ttm 101-200 201-=101-400 401-500 501-600 Cmbined Occurrence Z Bol.. PISM fteces (=identifiable) 1 1 1 3 2.9 7 ARTHROPODA Crustaces (unidentifiable) 1 1 2 1 5 4.9 42 ,Wphip- I 1 1.0 10 Callimeotes oapidus I 1 1.0 9-0 ChtAMMIUS f@O@Us 3 5 2 7 2 19 18.6 41 Cirrepedia I 1 1.0 <5 Coropblidm I 1 1.0 20 CIpathura polita 2 2 2.0 20 D-apoda 11 3 4 is 17.6 33 Spiothoniue b2nailie@ais I 1 1.0 90 EWVpamopeue depms 1 1 2 2.0 25 CUMMKIMB MaYOWtU8 I 1 1.0 <5 Opalipes ocelZatua 2 2 2 6 5.9 52 Posopeus hez-batii 2 1 1 4 3.9 15 portuma gibbeeii 1 3 4 3.9 45 Vrithmpanop harriaii I 1 1.0 60 Semarm aine 2 1 1 4 3.9 28 Sesarm retiouWtwN a I 1 10 9.8 24 Von puglilator 2 1 3 2.9 63 Vaa pug"mr 11 3 14 13.7 46 NDLLUSCA Nonvocs (unidentifiable) 1 4 4 4 3 16 15.7 37 Cardimn pi@tuzw I 1 1.0 @5 Oussostma virginioa 7 5 5 2 19 16.6 47 po"or omquiAa I 1 1.0 @5 Littoi-ima littoma 1 1.0 20 NDKoLw dommsma 3 6 2 1 12 11.8 38 shem-ims vibex 3 2.9 13 Adibpawhia 1 1.0 20 otiva sayow 1 1.0 10 thv"Ipins aissersa 2 2 2.0 5 Table 131. (continued) =th C Par eat Average Food Iten 101-200 201- 301Tp IV-500 501-W Combined Occucrrence I bolus CDXLMrrERkTA Astrangia dawe OP. 1 1 2 2.0 20 Hydroids (unidentifiable) 2 2 2.0 so ANNELIDA and ASCHELMEWTHES Nematode 1 1.0 .5 Tabificld" 3 3 2.9 23 Ambellarlid" I 1 1.0 90 SCRUMERHATA Arbwia punotuLata 1 1 2 2.0 80 Asteria forb"i 1 2 2.0 30 gahinoyachnius parma I' 1 1 3 2.9 27 Ophiodrown brevispina 1 1 1.0 10 PLANT Detritua 2 5 7 6.9 70 Spartina 41terniflora 2 4 6 5.9 18 Mao laotuaa 1 3 1 1 6 5.9 27 IMONGAMIC MATERIAL 2 C 3 4 5 2 16 15.7 43 PORIFOA liatiotow oculat'a 1 1 2 2.0 10 UADCHORDATA Asaidiama 2 4 3 9 8.8 46 Abtgula op. 9 6 15 14.7 37 FWrVPhOF4 Vil@ I 1 1 3 2.9 33 sessite tun@tea 2 1 3 2.9 30 ZKYOZOA *WuinalZa paZmata 26 6 1 33 32.4 35 AXIML TISSUE I 1 1.0 50 Number of stomachs' 117 Number and percent of stomach* containing food: 102 (97.22) Number and percent of empty stomachs: 15 (12.8Z) OF the major food sources were crustaceans and mollusks, but plant detritus, sea lettuce (Ulva Lactuca), and inorganic materials were also found. However, too few specimens were collected for this smaller size group to determine specific food preferences. One of the major items found in this size group was barnacles (ChthwnaZus fragiZis). In specimens 201-300 mm, the major foods were decapod crustaceans, primarily mud fiddler crabs (Uca pugnax) and wharf crabs (Sesarma reticuZatwn). Sea grapes (MoZguZa sp.) and the common oyster (Crassostrea virginica) were also frequently occurring items. Bryozoans were found in many stomachs, but were probably ingested incidentally while grazing for other species. In specimens over 301 mm crustaceans and mollusks were the main food items. The common oyster was the top food item followed closely by the ribbed mussel WodioZus demissus), barnacles, and ascidians. The 10 most frequently occurring food items in sheepshead stomachs are presented by season and sector in Table 132. In general, the most frequently occurring items throughout the year were bryozoans, oysters, barnacles, and decapod crustaceans. During winter, barnacles, sea lettuce, bivalve mollusks, and crustaceans were the most frequently occurring items (Table 132). Tn spring, foods were primarily barnacles, bryozoans and sea grapes. In summer, bryozoans, oysters, barnacles, and fiddler crabs were the top items. In fall, the major foods were oysters and mussels followed by mud and fiddler crabs and sea grapes. Major food items in the creeks were bryozoans, sea grapes, fiddler crabs and oysters. In the sounds mollusks were of major importance as oysters, mussels and unidentified bivalves were common foods. However, crustaceans were also important with several species of mud crabs and the common blue crab (CaZZinectes sapidus) being observed. No sheeps- head were collected from the beaches for food habitat studies. In off- shore waters major foods were barnacles, bivalve mollusks, ascidians and the common lady crab (Ovalipes ocelZatus). There was an increase in feeding activity from spring and summer to fall as the percentage of stomachs containing food rose steadily from 86.3 to 96.4% (Table 133). During winter, feeding acti vity dropped 261 Table 132. The 10 an t frequen ly occurring food items found in the stoge,chs of sheesphead, Arc;weargae pmbatooerhalw, by season and se,t,r for fish Ilocted tin Glym C@ounty, Georgia from January 1979 through June 1982. Winter Spring Sooner no. Percent Average MD. Percent Average Percent Average Sector Few Item, Stomache Occurrence 2 bolus food It- Stomachs_ Occurrence 2 Sol us food Item St= he Occur ence 2 Bolus crv@ mv--ime frwilia 3 33.3 73 Anguinella pal-t-a is 75.0 41 Anguinella julnuw 7 58.3 37 Unidentified material 2 22.2 as M01gul. op. a 40.0 48 Decapods 5 41.7 38 Won Zaotwa 2 22.2 $5 Chthamulae fragilis 6 30.0 37 Um pugilatr 2 16.7 75 wilumeat 2 22.2 20 Vc@ pugnax 5 25.0 60 Y@ pugnar 2 16.7 45 Crustacem 1 11.1 90 Sp@ti- alt-ernifZom 4 20.0 10 inorganic material 2 16.7 45 b-ioVwRi4w bmailiensio 1 11.1 910 Decapoda 3 15 0 20 Wlgula amhattensia 2 16.7 45 1plant d*trIt%w 1 11.1 70 Seoarwn cinereim 3 15:0 17 Cmasoatma vigini- 2 16.7 40 AnIMLI tLosaft 1 11.1 so 0-aesoatma virginim 2 10.0 45 Urowlpimr cinerea 2 16.7 5 corophlides 1 11.1 20 Unidentified material 2 10.0 45 Sea@ mti@latw 1 8.3 30 Liteop-iw !ittorw 1 11.1 20 Auroar-Cuo vibez 2 10.0 15 Part@ gibbeeii 1 8.3 20 sown& alwatwia 2 66.7 55 Spartim altemifZo- 1 100.0 so Crustaces 2 33.3 50 Oussaat@ virVinim 2 ".7 35 Unidentified material 1 100.0 so Callimect-es aapid@ 1 16.7 90 P-wp- op. 1 33.3 30 0-assostrea virginica 1 16.7 9-0 a-AVOWP- dv_ 1 33.3 3D Unidentified material 1 16.7 90 Samamor JVtioulation 1 31.3 20 sea@ ciw@ 1 16.7 60 Ulwa twtwm 1 33.3 10 Rhithrop@pew har,-iii 1 16.7 60 Decapoda 1 16.7 40 'P@tiw alt@mifzora 1 16.7 20 A"guinella poLimat-a 1 16.7 10 Panopeus op. 1 16.7 c5 Beeches RUNS I/ - NONE - - WME - - - offshore am - Clith@lus f@NVM. 10 43.5 33 Si'alvia, 2 IOD.0 45 51-1vi. 6 26.1 42 E@h;@Ch@iue P@ 2 100.0 30 Asr(did- 6 26.1 28 Decapo" 2 100.0 15 Opclip@s -11atuo 5 21.7 62 Unidentified moterial 1 100.0 20 Unidentified meterial 4 17.4 23 Anteriw forbeoi 1 100.0 10 Portuma gibbeeii 3 13.0 51 Send 1 100.0 @5 Decspada 3 13.0 10 Tubtficidoe 3 13.0 23 0-woostma virginim, 2 3.7 so Places 2 8.7 20 Tot&" Chthawl" fe%wilf, 3 23.0 73 Chthawl@ fragslis 16 36.4 34 Anguinella palmt. a 42.1 34 Koo Zaotwm 3 25.0 40 Anguinella paLmata is 34.1 41 Dcapoda 8 42.1 33 thoideetified material 2 16.7 85 MoLguza op. 8 18.2 48 C@,amaoatma oirginica 3 IS.6 57 uVolvis 2 16.7 S5 Unidentified material a 18.2 29 Crustaces 3 15.8 37 tvassoetrea virpim(@a 2 16.7 35 Ascidid" 7 15.9 46 Uea pwgilatr 2 10.5 75 Ballasts 2 16.7 20 U64 6 13.6 53 Unidentified material 2 10.5 55 Crustaces 1 9.3 90 Omzzr@o ocezzatus 6 13.6 52 Uca pignac 2 10.5 45 kPiothomims browitionvis 1 8.3 SO alvalvis 6 13.6 28 Inorganic material 2 10.5 45 Plant detritus, 1 8.3 70 Decapoda 6 13.6 25 Ablquta mtoghattensla 2 10.5 45 A-sp-Opme dopm* 8.3 30 spartfw aztemelzm 5 11.4 Is Sival,L& 2 10.5 45 "Ol@ WWO collected with food in stomach.. Table 132. (continued) Fall Combined Totals NO. Percent Average NO. Percent Average Sector Food Item Stomachs Occurrence 2 Bolus Food Item Stomachs Occurrence Solis 32 5,0.0 36 Cree1w Anguinella paboat-a 10 43.5 29 Anguinella paLmta Sesaym reticulatwn 8 34.8 24 MoIgula op. 15 23.4 37 Mytilidae 7 30.4 47 Uca pugnax 13 20.3 48 Vda Pagnax 6 26.1 38 Decapods 12 19.8 36 0-4soostrea virginica 6 26.1 37 crassoatem virginica 10 IS.b 39 M01gula BP. 6 26.1 30 Chthamalus fragilia 9 14.1 49 Organic materials 4 17.4 55 Sesarm reticulatwn 9 14.1 24 Decapoda 3 13.0 57 Mytilidae 7 10.9 47 Hydrozoa 2 8.7 so Plant material 6 9.4 47 Mollusca, 2 8.7 25 Mollusca 6 9.4 20 Sounds 0-aasoatrea Virginica 4 IW.O 70 n-aaaoatrea virginica 7 50.0 63 Mytilidse 3 75.0 30 Mytilidae 4 28.6 23 Cirripedis 1 25.0 5 Unidentified material 2 14.3 70 Crustacea 2 14.3 55 sivalvis 2 14.3 50 Spartina alterniflora 2 14.3 35 panopel's BP. 2 14.3 15 Cdllineates sapidus 1 7.1 90 Rhithpopanopeus harriaii 1 7.1 60 Sesarm ainerewR 1 7.1 60 Beaches 'M - - - - P.-) ON Offshore mm - Chthamalus f@@Iio 10 41.7 33 Divalvia, a 33.3 33 Ascididne 6 2S.0 42 ovalipea ocellatua 5 20.8 62 Decapoda 5 20.8 24 Unidentified material 5 20.8 22 Portunuo gibbesii 3 12.5 53 Echinarac;miua paren 3 12.5 27 Tubificidse 3 12.5 23 n-aosoatrea airginica 2 8.3 30 Totals 0-aaaoatrea Virginica 10 37.0 so Amuinelta palinata 33 32.4 35 Mytilidae 10 37.0 42 Craegostiva Llirginic,2 19 18.6 47 Anguinplla palmta 10 31.0 29 Chthamalus fragilia 19 18.6 41 Seearma retioulatw a 29.6 24 Decapoda la 17.6 33 Lfba pugnar 6 22.2 38 M01gula op. 15 14.7 37 Mozquta op. 6 22.2 30 Uoa pwgn= 14 13.7 46 Organic material 4 14.8 55 Unidentified material 12 11.8 43 Decapoda 3 11.1 57 Mytilidam, 12 11.8 38 Hydrazos 2 7.4 so Divalvia 10 9.8 37 Hollusca 2 7.4 25 Sesarm. reticulatton 10 9.8 24 -!/None denotes no specimens were collected with food In stomachs. Table 133. Number and percent of sheepshead, Archosargus probatocephalus, with stomachs containing food versus empty stomachs by season and sector for fish collected In Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Toter- Food ftoty Tot=a Food Empty Total NO. z NO. Z No. Z No. Z No. Z No. % No. Z No. 2 No. 2 Winter 9 64.3 5 35.7 14 100.0 3 75.0 1 25.0 4 100.0 - - - - - - Spring 20 90.9 2 9.1 22 100.0 1 100.0 0 0.0 1 100.0 23 82.1 - - - - S r 12 92.3 1 7.7 13 100.0 6 100.0 0 0.0 6 100.0 - - - - - - Fall 23 100.6 0 0.0 23 100.0 4 80.0 1 20.0 5 100.0 - - - - - - Total 64 88.9 8 11.1 72 100.0 14 87.5 2 12.5 16 100.0 - - - - - - 41 rood Of famro Total Combined Sectors Total Winter - - - - - 12 66.7 6 33.3 is 100.0 Spring 23 82.1 5 17.9 28 100.0 44 86.3 7 13.7 51 100.0 S@r 1 100.0 0 0.0 1 100.0 19 95.0 1 5.0 20 100.0 Fall - - - - - - 27 96.4 1 3.6 28 100.0 Total 24 82.8 5 17.2 29 100.0 102 87.2 15 12.8 117 100.0 VM: A dash denotes none collected. A Ah sharply as only 66.7% of the stomachs contained food. This was probably due to a decrease in food supply as well as decreased metabolic rate. Feeding activity appeared to vary little between sectors as over 82% of the stomachs contained food in each sector (Table 133). Although only a slight difference was observed, feeding activity was greatest in the creeks as 88.9% of the stomachs contained food. Temperature apparently had little effect on feeding behavior at temperatures above 160C as over 85% of the stomachs examined contained food. However, at temperatures below 15 0C, the percentage dropped to 50%. Little correlation between moon phase and feeding habits could be determined as so few specimens were collected. The percentages of stomachs containing food versus empty stomachs are presented by lunar phase in Table 51. ATLANTIC CROAKER The geographic distribution of the Atlantic croaker (Micropogonias unduZatus) includes the northern and western parts of the Gulf of Mexico, along the Atlantic coast from south Florida to Massachusetts, the Greater Antilles, and alonL the South American Atlantic coast from Surinam to 9 Argentina (Fischer, 1978). Croaker generally prefer sandy hard rocky bottoms or shallow firm bottom areas adjacent to oyster reefs. However, larger croaker are more common in the deeper waters of channels in rivers and sounds during the summer and early fall months and move to offshore waters during colder months. Juveniles are common throughout the estuaries during the warmer months. However, larger juveniles (>50 mm) become scarce in in- side waters during the colder months while smaller juveniles (<50 mm) become abundant in the upper portions of the estuaries during late fall. Movement and Migration From April 3, 1979 through June 28, 1982, 3,456 Atlantic croaker were tagged and released. Length frequencies of tagged croaker in 50 mm 265 length groups are presented in Table 134. Lengths (TL) ranged from 130 to 358 mm for fish tagged with Howitt tags and 90 to 324 mm for those tagged with Floy tags. Length frequencies of croaker tagged with each tag type are presented in Table 135, and Table 136 lists the length fre- quencies in 20 mm groups by gear type used for capture. Tagged croaker were returned from September 25, 1979 through September 26, 1982. 0 f 3,-456 croaker tagged, 87 (2.5%) were recap- tured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged as high as 50%. However, this peak return rate represents only one recapture. The next highest return rate was 13.5% for croaker measuring 251-300 mm. The number of fish released and re- captured, time at large, and distance traveled are presented in Table 134. Time at large ranged from 2 to 416 days with an average of 63 days. Distance traveled ranged as far as 179 km, averaging 10.9 km. The recovery rate for croaker tagged with Howitt tags was 4.2% as opposed to only 0.5% with Floy tags (Table 135). However, such return rate comparisons are misleading unless the sizes of tagged fish are considered. Approximately 77% of all croaker tagged with Floy tags were smaller than the minimum size recorded from re 'ireational recaptures. In contrast, only 36% of those tagged with Howitt tags were smaller than the minimum length of recreational recoveries. Recreational fishermen were the major source of recoveries, ac- count ing for 50 (57.5%) of the 87 returns. Thirteen (14.9%) returns were by commercial fishermen, and study activities accounted for the remaining 24 (27.6%) recoveries (Table 11). Of 50 recreational recap- tures, 27 (54%) included sufficient information to determine lengths of creel size fish. Recreational recapture lengths ranged from 167 to 330 mm with an average size of 253 mm (Table 12). Recapture lengths indicated that most creel size fish ranged from 200 to 300 mm with the greatest occurrence at 250-300 mm (Table 13). The creeks produced 47.7% of all recaptures, with 58.5% of the re- coveries from the creeks being taken during spring (Tables 14 and 15). The sounds produced 36.1% of all recoveries with most of the returns for 266 Table 134. Number tagged, number and percent recaptured, days at large and distance traveled for Atlantic croaker, Micropogonias undulatus, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled km) Length Group Tagged Recaptured Returned Avg. Max. Avg. Max.- 51 - 100 33 0 0.0 101 - 150 892 4 o.4 33 65 13.9 19 151 - 200 1,908 27 1.4 83 416 16.1 113 201 - 250 406 27 6.7 55 191 13.0 179 251 - 300 207 28 13.5 57 187 3.7 28 301 - 350 8 0 0.0 351 - 400 2 1 50.0 106 0 Total 3,456 87 2.5 63 416 10.9 179 l/ Distance measured in kilometers from point of release to point of recapture. Table 135. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 nun length groups for Atlantic croaker, Micropogonias,undulatus, tagged in Glynn County, Georgia from January 1979 through June 1982.' Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numb&r Number Percent @mm) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 75 33 33 125 46 846 4 0.5 892 4 0.4 175 1,274 24 1.9 638 3 0.5 1,908 27 1.4 225 374 27 7.2 30 405 27 6.7 275 203 28 13.8 2 206 28 13.6 325 7 1 8 375 2 1 50.0 2 1 50.0 Total' 1,908 80 4.2 1,546 7 0.5 3,454 87 2.5 NOTE: Number tagged and recaptured does not include the two fish tagged with both tag types. 0 d1k Ah Ah Table 136. Number of Atlantic croaker, Micropogonias unduZatus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length l/ Group Gill Net (in) Trammel Cast Hook/ (mm) 2 2-7/8 4-5T8 6 Net Trawl Net Trap Line Totals 90 - - - 33 - - 33 C 110 382 - - - 382 130 - 320 - - 1 321 150 1 - - - - 540 - - 2 543 170 16 10 - - 17 910 - - 21 974 190 21 15 - - 32 471 1 - 41 581 210 4 13 - - 34 141 1 - 22 215 230 1 28 2 - 9 37 - 1 32 110 250 7 95 - - 10 36 - 19 167 270 1 53 - 1 7 15 7 84 290 1 28 1 1 4 1 - 36 310 - 4 - - 1 2 7 330 - - - 1 1 350 - 2 - - - - - - - 2 Totals 52 248 3 2 114 2888 2 1 146 3456 yGill net sizes are stretch mesh measurements. this sector during the summer (58.1%). The beaches and offshore waters each contributed 8.1% of the recoveries with most returns taken during fall (57.2%). In general, summer produced the highest number of returns and winter produced the lowest. Georgia residents fishing in state waters accounted for 42 (84%) of the 50 recreational recaptures. Of these resident fishermen, 32 (76%) traveled 40 km or less to reach the location of fish recapture while approximately 90% traveled less than 120 km (Table 16). Shrimp was the only reported bait used by recreational fishermen to recapture croaker. Approximately 84% of all croaker recaptures were caught by recreational fishermen using dead shrimp. Live shrimp accounted for the remainder (Table 17). Approximately 5Q.6% of the recoveries were caught in the immediate area of release. Of 86 recoveries with sufficient information to ascer- tain movement, 79 (92%) were recaptured within 25 km of the release site. Four recoveries (4.7%) had moved 26 to 50 km, and three (3.5%) moved over 100 km (Table 137). Of three croakers traveling over 100 km, two moved southward (138 km) and were recaptured during May and August in the St. Johns River near Jacksonville, Florida. The third specimen moved northward (179 km) and was recaptured in May near Cane Island, South Carolina. Spring was the season of greatest movement with an average distance of 15.8 km (Table 21). Movements during summer and fall were similar, averaging 9.1 and 8.2 km, respectively. Winter produced least move- ment, but this conclusion is based on a single return at large 105 days and caught in the area of release. Approximately half (48%) of all recaptures were caught in the general area of release (Table 138). As indicated by the greater number of recaptures that moved in a creek to beach direction after tagging, there was greater movement out of the estuary. After emigrating from the estuaries, most croaker (82%) moved southward. Recovery data indi- cated that very few creel size croaker remain in the estuaries during winter. 270 Table 137. Days at large and distance traveled for Atlantic croaker, Micropogoniaa undulatu8, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At Distance Traveled (ka) -Large 0 0.1-1 1-5 6-25 26-50 51-100 101-200 Total Percent 1 - 50 27 4 5 11 - - - 47 54.0 51- 100 13 - - 8 1 1 23 27.1 101 - 150 3 1 - 1 2 - 7 8.2 151 - 200 1 - 1 3 - 1 6 7.1 201 - 300 - - 1 1 2 2.4 301 - 500 - - - - 1 - 1 1.2 Total 44 5 6 24 4 3 86 100.0 Percent 50.6 5.9 7.1 28.2 4.7 3.5 100.0 Table 138. Seasonal movement of Atlantic croaker, Micropogonias undulatus, tagged In the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved ft Recaptured Tagged Fish Length Group Caught In Area Movement Within got movement Out Of Estuary Season (mm) Of Release Creek to Beach BeachTuCreek North South Winter 101-150 151-200 201-250 - - 251-300 1 - Total 1 - Percent 100.0 - Spring 101-150 - 1 - 151-200 2 2 1 201-250 11 1 - 1 1 251-300 5 - - - I Total 19 4 1 1 3 Percent 66.7 14.8 3.7 3.7 11.1 Summer 101-150 - 1 1 1 - 151-200 2 3 1 1 2 201-250 5 - - - 2 251-300 5 3 - - 3 Total 12 7 2 2 7 Percent 40.0 23.3 6.7 6.7 23.3 Fall 101-150 - - - - - 151-200 1 1 7 201-250 1 - - - 251-300 4 .1 2 1 1 Total 6 2 2 1 8 Percent 31.6 10.5 10.5 5.3 42.1 Combined Total 37 13 5 4 18 Percent 48.0 16.9 6.5 5.2 23.4 A Length-Weight Relationship The length-weight relationship for 260 Atlantic croaker ranging from 84 to 389 mm and 7 to 765 g was log W = 3.195 logL -5.367. The correlation coefficient value for length-weight for croaker was 0.9632 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male, female, and all Atlantic croaker combined are shown in Table 24. Figure 36 illustrates the length-weigbt relation- ship for Atlantic croaker. The greatest lengths recorded for male and female Georgia croaker were 291 and 389 mm, respectively. The heaviest specimens were 270 g for males and 765 g for females. Comparison of length-weight relationships for several populations of Atlantic croaker are shown in Table 139. Age and Growth Age and growth studies based on the scale technique have been validated as an ageing method for Atlantic croaker (Arnoldi, Herke, and Clairain, 1973; White and Chittenden, 1977; Barger and Johnson, 1980). Croaker generally appear to form two annulus-like marks per year. White and Chittenden (1977) described the characteristics of the two annulus-like scale markings used to determine the age of croaker. The first mark is a light mark formed in warm periods and characterized by only a few new circuli cutting over older incomplete circuli in the lateral field. However, the first mark has little or no differential spacing of circuli before or after the mark. The second mark is formed in cold periods and characterized by 'heavy cutting over of circuli and differential spacing of circuli in the lateral fields. The second scale mark was considered to be the true annulus and was the basis for ageing Atlantic croaker. Scale samples from 272 Atlantic croaker ranging from 93 to 389 Mm were examined and 248 (91%) were considered legible for age determinations. Otolith sections from these 248 fish were examined to document scale ring counts. Rings on otoliths formed simultaneously with the second scale mark described above. The first annulus-like mark on scales were in- distinct and were often undetectable. 273 800-- IV= .000004 L3.195 700-- n= 260 r2 96 600-- ,---1500-- 400 CD 300-- 200-- 100-- 5 10 1@ 20 25 30 35 40 TOTAL LENGTH (CM) Figure 36. Length-weight relationship of Atlantic croaker, Micropogonias undutatus, collected in Glynn County, Georgia from January 1979 through June 1982. 274 Table 139. Comparison of total length-weight relationships for several populations of Atlantic croaker, Micropogonias undulatua. Length-Weight Weight of Fish (g) Study Location Equation 100 mm 200 mm 300 mm t..n Dawson (1963) Mississippi and log W - 3.148 logL -5.285 10 91 326 Louisiana White and Texas and log W - 3.15 logL 5.26 11 97 349 Chittenden (1977) Louisiana Present Study Georgia log W - 3.195 logL -5.367 10 90 328 calculation of mean monthly growth of marginal increments vali- dated that scale annuli (second scale mark type) were formed only once annually. Annulus formation was detectable during March, April, and May. Least-squares regression analyses on the relationship between fish length and scale radius were performed. An r 2value of 0.87 (P < 0.0001) suggests back-calculations based.on fish length/scale radius would be reliable for estimating fish length at time of annulus formation. Em- pirical and mean back-calculated total.lengths at age for Atlantic croaker are presented in Table 140. Table 141 shows the empirical and weighted mean back-calculated lengths for juvenile, male, female, and all croaker combined. Figure 37 illustrates length-age relationships, and Table 142 shows the length-age equations for croaker. Typically, the life span of croaker on both the Atlantic and Gulf coasts appears to be two years (White and Chittenden, 1976). Although older croaker are uncommon, five year old fish have been collected in the Gulf of Mexico (Barger and Johnson, 1980) and in Georgia (present study). The largest specimen collected during this study was 389 mm while the largest sp ecimen reported by Mahood et al. (1974) was 443 mm. Mean lengths for one year old croaker from several populations ranged from 108 to 274 mm (Table 142). Weighted mean back-calculated lengths determined for one year old croaker in Georgia were fairly consistent with lengths reported from many areas. Furthermore, lengths of older Georgia croaker were similar to those reported in the Gulf (Barger and Johnson, 1980). Maturity and Spawning From the data collected during a previous three-year estuarine survey of Georgia's coastal,waters it was concluded that the spawning season for croaker was August through November (Mahood et al., 1974). It was also reported that juvenile croaker were found throughout Georgia's estuaries in all months with peak abundance from May through September. The data collected during this study,, however, indicate that croaker spawning activity probably extends from as early as August to as late 276 Table 140. Mean back-calculated total lengths for Atlantic croaker, Micropogonias undulatus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Length Range Mean Length Lengths of Successive Scale Rings Age Number at Capture at Capture 1 2 3 4 5 0 137 92 - 249 148 1 82 160 - 318 248 169 Eli 2 27 213 - 336 268 149 233 3 1 297 297 161 214 263 4 0 5 1 389 389 183 270 316 346 362 Weighted Means 164 233 290 346 362 Growth Increment 164 69 57 56 16 NOTE: Lengths measured in millimeters. Table 141. Number, empirical and back-calculated total lengths, and growth increments by sex and age for Atlantic croaker, Micropogonias undulatua, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Age Sex 1 2 3 4 5 Juveniles Number 5 1 Mean Length at Capture 226 240 Back-Calculated Length 170 233 Growth Increment 170 63 Males Number 16 9 Mean Length at Capture 249 253 Cn Back-Calculated Length 161 225 Growth Increment 161 64 Females Number 61 17 1 0 1 Me-an Length at Capture 250 278 297 389 Back-Calculated.Length 164 237 290 346 361 Growth Increment 164 73 53 56 15 Combined Number 82 27 1 0 1 Mean Length at Capture 248 268 297 389 Back-Calculated Length 164 233 290 346 361 Growth Increment 164 69 57 56 15 NOTE: Lengths measured in millimeters. 40 A= .000047 L 1.953 35 n= 260 r 2 .14 30 0 I_' 7- 25 z W _j 20 0 15 10 5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 AGE (YEAR) Figure 37. Length-age relationship of Atlantic croaker, Micropogonias unduZatus-, collected in Glynn County, Georgia. 279 Table 142. Comparison of lengths at age for several populations of Atlantic croaker, Micropogonias undulatus. Length at Age (am) Study Location I II III IV V Welsh and Breder New Jersey 150 (1924) Pearson (1929) Texas 150 Hildebrand and Cable North Carolina 143 (1930) Haven (1957) Virginia 175-180 00 Hansen (1970) Florida: 1964 108 1965 130 Herke (1971) Louisiana 274* Aronoldi (1973) Louisiana 235* White and Chittenden Texas and Louisiana 181 270 (1976) Barger and Johnson Gulf of Mexico 169 224 268 305 337 (19bo) Present Study Georgia 164 233 290 346 361 NOTE: An asterisk denotes converted from standard length to total length using the formula TL - 1.37 SL. ti (I ti 41 as April, with peak activity in September and October as advanced stages (stages IV through VII) were collected from inside waters during these two months (Table 143). This study had limited utilization of trawls in ocean waters which resulted in limited collection of adult croaker in spawning condition. It is generally agreed by other investigators that most spawning takes place at the entrance of bays and at sea. our data appear to agree with that of Hildebrand and Cable (1930) in that spawning activity may last as long as nine months, peaking in September and October. They also agree with Bearden (1964) in that 31 most spawning activity probably takes place in offshore waters. Lunz (1955) reported that spawning in South Carolina takes place in offshore waters beyond the limits of normal shrimping operations. This probably explains why very few advanced stages of gonadal development are taken from Georgia's inshore waters. Since our sampling technique utilized primarily gillnets in the inside waters from the beaches to the creeks, sampling design limited the collection of adult croaker. Advanced maturity stages were collected only during September, October, and March and were not found at salinities below 16 0/oo (Table 144). Advanced maturity stages were collected only from temperatures below 280C and salinities higher than 16 0 /oo (Table 145). These specimens came from the mouth of Dubignion Creek on the north end of Jekyll Island near the seaward end of St. Simons Sound. one postlarval croaker was collected in ichthyoplankton samples from the beach in January (Table 63). However, plankton samples were contracted for identification only during the 5-month period from January through May. Young croaker were collected in trawl samples during all seasons with an increasingly higher occurrence rate from the low in summer to the peak during spring (Table 52). They were also collected in all sectors, but were most abundant in the creeks and rivers (Table 53). The smallest specimens for which sex was determined through gross examination were 108 mm for females and 110 mm for males, These fish were age 0, or in the first year of life. The smallest female ex- bibiting developing ovaries (stage III or greater) was a 182 mm specimen 281 Table 143. Number of Atlantic croaker, Micropogonias undulatus, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage I III IV V VI VII Month F R 7- M F M F M F T M F M January 2 0 February 1 0 March 3 7 1 0 April 2 1 May 5 2 June 8 1 July 36 15 August 21 2 1 0 September 15 4 13 0 6 0 2 0 October 0 1 1 1 2 0 2 0 November 1 0 December 5 1 Table 144. St.$.. of gonadal development for Atlantic croaker, NiamffiJoniad, undulates. by month, sex and salinity gradient for fish collected In Glynis County, Georgia from January 1979 thr sgh June 1982. -surface Water Salinity (0100) Reproductive 34-30 -11---3ff 3ft-40 Tq1jl* Anati Stake -F-Pf -Y F N January I 1 0 1 0 2 0 11-vil - - February I 1 0 li-VII six Hatch 3 4 0 3 3 7 or IV V 1 0 VI Vil April I I 1 0 0 1 2 1 If-Vil - - - - - may 1 1 2 1 5 2 it-VII - - - - - Jun. I 1 0 5 1 2 0 II-VII July 1 4 1 -1 1 2 19 a 6 2 36 14 11-VII - August I 1 7 0 9 2 4 0 21 2 if 1 0 5 2 1 1 7 1 2 0 15 4 4 0 1 0 11 0 2 1 0 IV - v 1 2 0 VI - - VII October I 2 0 IV 2 0 2 0 V-VII - - - - M-emb.-r I - - - 0 1 0 If-V11 - - - - Decmb,-r I - - - 5 1 It-vtt - - - Combined I - - 1 4 1 17 h 21 11 44 13 13 2 14)() 3j Total It - - 5 0 0 1 9 0 1 0 Is I 111 4 0 1 0 - - 1 0 8 0 IV - - - - 2 0 2 0 v I 1 0 VI V11 283 Table 145. Stages of gonadal development for Atlantic croaker, Micy-opogonias undulatua, by water temperaturp and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surfaco Water T!Merature (00 Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 - 31-35 Totals (0/00) Stage F M F N F M N M F M F M 6-10 1 1 1 0 II-Vil - - 1 4 1 4 1 0 1 0 5 4 8 3 1 0 t6 7 0 0 4 0 1 0 5 0 2 0 2 0 4 0 16-20 IV - - - - - - V 1 0 1 0 2 0 VI Vil 1 3 1 0 18 6 21 10 00 41 0 1 0 1 t 0 1 0 21-25 IV V 1 0 1 0 Vi Vil 5 0 1 2 17 7 21 4 -44 13 1 0 8 0 9 0 26-30 111 - - - - IV 2 0 2 0 V-VII - - - - 1 1 0 6 1 6 1 13 2 11 1 0 1 0 31-33 111 1 0 1 0 IV-VII - - 1 8 1 2 3 8 6 49 17 32 6 99 33 1 1 13 0 1 0 -15 1 2 0 4 0 6 0 TOTALS IV - - 2 0 0 V 1 0 2 0 Vi VII (age 0). No advanced stages of development were observed in males, and the smallest stage II male was a 255 mm specimen (age I). Bearden (1964) reported collecting 23 sexually mature South Carolina croaker over 166 mm in September, and several appeared ready to spawn. He reported that females over 178 mm were ripe or nearly so and males over 137 mm had running milt. Lassuy (1983), reporting from the litera- ture, stated that maturity is reached at the end of the second year, but some fish may spawn before their second year. Wallace (1940) reported that croaker reach maturity at 240 mm for males and 275 mm for females or at age two and three years, respectively. Suttkus (1955) reported first spawning at the end of the second year of life. Hansen (1970) reported that croaker may spawn in their first year of life near Pensacola, Florida. White and Chittenden (1977) found that Texas croaker start to mature at about 140-170 mm TL. The five female croaker exhibiting advanced gonadal development were collected three days prior to first quarter, three days prior to last quarter, and during a split phase of lunar activity (Table 40). These phases were all during periods of neap tides or low tidal ampli- tude. However, since only five specimens were collected, no conclusions can be drawn between lunar phases and spawning activity. Females outnumbered males 3.7:1 (Table 41), and dominated at all salinity levels with over 66.7% of the catch at each level (Table 144). As shown in Table 40, Atlantic croaker exhibiting advanced repro- ductive stages were virtually absent in collections made in Georgia estuaries, prohibiting the determination of fecundity for this species. However, fecundity was reported by Hansen (1970) to be approximately 41,200 eggs for 18 west Florida croaker. Hansen further reported these fish (101-145 mm SL) to be near the end of the first year of life. Food Preference and Feeding Habits Of 267 Atlantic croaker examined to determine food preferences and feeding habits, 236 (88.4%) contained food and 31 (11.6%) were empty. Food items identified in stomachs from fish grouped in 100 mm length groups are presented in Table 146. Juvenile croaker <100 mm 285 table 1". Stomack coatests of ALLastic croaker, NidrapWum(@w wu&l4tus, collectod is Glym comaty. Georgia from Jamary 1979 througb Jwmm 1942. tb Group (-j Percest Average Food Item 1-100 to= ZOI-30) 301-400 CombLmod Occurrence Zmalus FISCIS Pieces (matdautifiable) I Z'l i's '17 21.6 sl Fwl&l"O 0.4 90 CoUoidee bm@cuwti 1 1 0.4 90 uphilohthue aphia 1 1 0.4 60 Cpaww tau 1 1 0.4 60 s)mph- plagi- 1 1 0.4 60 ARTMOVOM Crustaces (ancidestiflablO 2 53 14 69 ".2 36 AqvUsm abdita 1 1 0.4 hwhipoda I 1 3.6 16 Acetce anwri4upw 4 4 1.7 35 A446--w heteroohelis 3 9 2 14 5.9 hutharldae 1 1 0.4 IQ Callimmuiva atlmtioa 1 1 0.4 N callfwates vapi&w 2 2 0.8 C', co"Alidue I 1 0.4 C@katkum ; V w 2 6 a 3.4 DOCAP040 1 14 11 1 27 11.4 burypawpew depremew 1 2 '1 1.3 57 Diptem 1 1 0.4 20 rpweota 1 1 0.4 10 lkLita ftitida 1 1 0.4 10 WaLdse 1 1 0.4 10 O"Pidea a4Awmetple 4 4 1.7 35 palaomanates op. 1 2 3 1.3 43 Pawpeue herbotii 5 5 2.1 40 Peaseld.e 1 2 3 1.3 63 Peivaeuo dkorartm 1 1 0.41 PenaeuO actiferwo 1 1 0.4 go popt gibbvaii 1 1 2 0.9 53 Scoarm cifterelm 2 2 0.6 20 Sesarma rutioulatum 1 1 0.4 60 Squilla emcwoa 5 2 7 3.0 83 ,*w4pew" oonqtri@tmj I 1 1 5 2.1 Lloa pugilator 5 5 2.1 so Uca pugnax 3 3 1.3 67 Orl Table 146. (continued) Lealth Group (,) Percent Average food Item 1-100 101-200 201-300 301-400 Combined occurrence Zbolus MOLLUSCA Mollusca, (unidentifiable) 4 10 1 15 b.4 58 Brachidonte8 reourvus I 1 0.4 50 ovesoatrea viginica I 1 2 0.8 15 CEPHALOPODA Lolligunauta breviB 1 2 3 1.3 23 AN NEL IDA and ASCHELMENTHES Glyceridae 2 2 0.8 30 Nematode 1 2 3 1.3 17 Wereidae 1 3 4 1.7 30 Nicolea aimpl= 47 35 82 34.7 51 Orbinlidae I 1 0.4 <5 NWnchoooela I 1 0.4 50 S4bellidae I 1 0.4 <5 Spionidae I I 1 3 1.3 30 C3 Tubificide I 1 0.4 40 PLANT Detritus 26 16 42 17.8 42 Spartina atterniflora 2 35 4 41 17.4 45 IJIDIJGMC MATERIAL 2 17 7 26 .11.4 70 UROCHDRDATA kfolgula sp. I 1 0.4 40 WIgula mumhattenais 1 1 0.4 90 BRYOZOA AnpuinelLa palwta 1 1 0.4 10 ANIMAL TISSUE 2 2 0.4 90 Number of stomachs: 267 Number and percent of stomachs containing food: 236 (88.4%) Number and percent of empty stomachs: 31 (11.6) fed mainly on crustaceans and annelid worms, but no single food item dominated as the preferred food. In specimens 101-300 mm annelid worms, mainly polychaetes, were the dominant food. The most frequently occur- ring species was the polychaete, NicoZea sinTlex. There was some inclusion of fish in the diet of specimens over 101 mm, but the only fish identified to species level was a tonguefish, Synphurus pZagiusa. A limited sample of large croaker (>301 mm) were collected, but snapping shrimp, crabs, and mollusks were found in stomach contents. Pearson (1929) reported that smaller Texas croaker fed mainly on annelids, particularly polychaetes, but no crabs and mollusks. However, in larger fish, shrimp were the main item, followed by annelids, fish, crabs, mollusks and other mixed diet. Chao and Musick (1977) found polychaetes and crustaceans as the main food items in the York River in Virginia. Stickney et al. (1975) suggested an opportunistic feeding pattern for Georgia croaker, with the most commonly ingested food items being mysid shrimp and polychaetes. The 10 most frequently occurring food items in croaker stomachs are presented by season and sector in Table 147. Major foods consumed were annelid worms which occurred in 34.7% of the stomachs. However, crus- taceans were also consumed in fairly large quantities (29.2%). Fish and fish parts were found in 15.7% while mollusks occurred in only 4.7%. Plant materials were observed in many stomachs, but were probably in- gested incidentally as a result of the croaker's bottom feeding habits. There was significant variation in food preferences from season to season. Snapping shrimp were the dominant food item during winter, but annelid worms and bivalve mollusks were also ingested (Table 147). In spring, the major food source was crustaceans which occurred in 45.1% of stomachs containing food. Annelid worms and fish parts were also major foods with each comprising 26.8%. Smooth cordgrass (Spartina alterniflora) was observed in over half the stomachs, but ingestion of this and other plant materials was probably more a result of incidental ingestion rather than directed feeding effort. During summer, annelids and crustaceans were the major food components, occurring in 46.1% and 288 IL P Table 147. The 10 most frequently oeeurring food LtaRM found in the stomach. of Atlentle croaker. by season and ..et,,r for fish collected In Glyan County. Georgia frow January 1979 through June 1982. Winter Sprins S@er so Percent Average No. Percent Average NO. Percent A-rage Food I tea Stomachs Occurrence Z Bolus Food I tem -Stomocho Occurrence 2501 Food Item Stomachs Creek. A-:,:, - sp. 4 57.1 as Annelida 6 54.5 63 Annellda is 36.0 49 ftl@alvia 2 26.6 90 Piaces 2 18.2 70 Or&-ic material 12 24.0 27 Annelida 1 14.3 90 alt"MlifloA, 2 15.2 30 Decapoda 9 18.0 48 Plant detritus 1 14.3 20 Blvalvia 2 18.2 25 Crustacea 7 14.0 36 Squil"a 1 9.1 90 Hollusca 6 12.0 43 or,awute t@. 1 9.1 60 V- ;-wji1d:or 5 10.0 80 linide,ntified material 1 9.1 60 Aq,;,w op. 5 10.0 46 1 9.1 so *a1,Luftz P, 4 8.0 83 Plant detritus 1 9.1 40 UnideratMed material 4 8.0 65 Crustacea 1 9.1 40 P,,@P,@ op. 2 4.0 70 Unid-titid witerial 3 25.0 83 S7,-LF,-. ":tc,n*j'-'.-- 3S 59.3 /15 An-I Ida 35 5,4.7 @fi Anne I Ida 1 25.0 37 Crustacea 33 55.9 34 Crustace. 22 34.4 30 pl- 2 16.7 90 Piece. 16 27.1 53 Organic material 22 34.4 30 C-t.-, 1 8.3 90 Aaaelida 13 22.0 so Places 7 10.3 34 . . ; n .. - ., p. 1 8.3 )0 Decap la 10 6.9 32 Unidentified material 7 10.3 30 ik.-f-ja 1 8.3 90 Awphl.oda 7 11.9 17 Decapoda 5 7.8 6:1. orga.i, material 1 9.3 90 Unidentified material 4 6.8 go -@jliljl 7TIUV. 3 4.7 77 Animal ti- 1 8.3 90 rluilla 3 5.1 87 3 4.7 63 Plant &-tritus 1 8.3 so lltoda 3 5.1 17 A1,,iu 2 3.1 80 1.1,11 I,id- 1 8.3 40 Inorganic material 1 1.7 90 Inorganic materials 2 3.1 50 Piece. 1 100.0 Ion Unidentified material 1 100.0 too 03 i,hore N NONE - - - - - - WINE - - 4 21.1 98 i., Md., -10^2 37 52.1 44 Annelida 53 4b.1 47 Anne I Ida 4 21.1 so cr-tac.. 32 45.1 34 Plant material 34 29.6 29 Unidentified material 3 15.8 93 Piece. 19 26.8 57 Crustacea 29 25.2 32 Bi-1via 2 10.5 90 Anne I Ida 19 26.8 54 Decapda 14 12.2 53 Plac- 2 10.5 90 Decapoda 10 14.1 32 Unidentified material 12 10.4 40 Plant detritus 2 10.5 50 Amph I pods 7 9.9 17 Places 9 7.8 28 Crust-S t 5.3 90 Uoldutlfld material 5 7.0 84 A,'jh,@ sp. 7 6.1 56 Plant material 1 5.3 90 4 5.6 88 Mollusca 7 6.1 44 pa-1-M ":, t. a op. t 5.3 90 Ace tee vk rfcanup 4 5 6 35 Y,@ pujilatr 5 4.3 so Decapoda, 1 5.3 90 Nematode 3 4:2 17 @!,a taum I , I i t@ 4 3.5 83 m,m, denotes no specLowas were collected vith food In stoLacho. Table 147. (continued) ... Fall Combined Totals NO. Percent Average NO. Percent Average Sector Food Item Stomachs Occurence I Bolus Food Item Stomachs Occurrence Z Bolus Creeks Annelida 4 40.0 90 Annelids 29 37.2 59 Crustacea 2 20.0 so Plant material 12 15.4 27 Pisces 2 20.0 30 Alpheus sp. 10 12.8 67 Alpheua sp. 1 10.0 90 Crustacea 10 12.8 39 molluscs 1 10.0 90 Decapoda 9 11.5 48 Spionidae 1 10.0 90 Molluscs 7 9.0 50 Unidentified material 1 10.0 so Unidentified material 6 7.7 67 Y'rachypeneus constrictuo 1 10.0 50 Pisces 6 7.7 35 cyatjtum polita 1 10.0 20 Uca-pugilator 5 6.4 so Ogyri4es alphaerostria 1 10.0 10 C@athum polita 5 6.4 70 Sounds Pisces 5 25.0 64 Crustacea 59 38.1 35 Crustacea 5 25.0 54 Annelida 53 34.2 46 C@athuro polita 3 15.0 67 Spartina alterniflora 36 24.5 47 2'rachypeneus consti-ictus 2 10.0 90 Pieces 30 19.4 53 Decapoda, 2 10.0 so Plant material 25 16.1 34 Annelid& 2 10.0 40 Decapoda 18 11.6 46 Ogyridee alphaemstris 1 5.0 90 Unidentified material 14 9.1 59 Alpheus sp. 1 5.0 90 Amphipoda 9 5.8 16 Peneeidae 1 5.0 90 5?ui I Za enpusa 6 3.9 82 Eurypanopeus depreasua 1 5.0 90 Alpheus op. 4 2.6 65 Reaches molluscs 1 100.0 100 Pisces 1 33.3 90 Molluscs 1 13.3 90 Unidentified material 1 33.3 10 offshore NMI/ - - - NME - - - Totals Places 7 22.6 54 Annelid& 82 34.7 51 Crustacea 7 22.6 53 Crustacea 69 29.2 36 Annelid& 6 19.4 73, Spartina alterniflora 41 17.4 45 Cyathura polita 4 12.9 55 Pisces 37 15.7 51 Trachypeneus oonstrictus 3 9.7 77 Plant material 37 -15.7 31 Alpheus sp. 2 6.5 90 Decapoda 27 -11.4 46 Ogyrides atphaerostris 2 6.5 so Unidentified material 21 8.9 59 AaVpanopeuo depresous 1 3.2 90 Alpheus up. 14 5.9 66 Pen&eidae 1 3.2 90 molluscs 11 4.7 46 Calliawaaa atlantica 1 3.2 so Amphipods 9 3.8 16 y NOW denotes no specimens were collected with food In stomachs. 25.2% of the stomachs, respectively. Plant materials were found in 29.6% of summer stomachs. The most frequently ingested crustaceans during summer were snapping shrimp (Alpheus sp.) and sand fiddler crabs (Uca pugiZator). Although crustaceans were the primary food source during fall, fish were ingested more frequently than at any other time of the year as 22.6% of the stomachs contained fish and fish parts. Annelids were ingested less frequently than fish during fall. The slender isopod (Cyathura poZita) and the small penaeid shrimp (Trachypeneus constrictus) were the major crustaceans observed in the fall diet. Stickney et al. (1977) found that the main food items in their study in and near Georgia were harpactocoid copepods during spring and calanoid copepods in summer. During fall the major foods were polychaetes, mysid shrimp, and other crustaceans. In winter harpacto- coid copepods were again dominant. In smaller specimens (less than 39 mm SQ they found that harpactocoid copepods were numerically domi- nant and were present along with calanoid copepods in all length groups of fish up to 99 mm SL. In fish above 99 mm SL the major foods were crustaceans and polychaetes. They also noted that relatively larger amounts of other organisms were ingested as croaker grew and that larger specimens may have grown too large to feed efficiently on smaller copepods. Fish were also found in increasing frequency with increasing size in larger specimens. Although major food sources were the same, there was some differ- ence in ingestion rates between sectors. In the creeks, annelid worms and crustaceans were the major food items. Annelids were found in 37.2% of the stomachs containing food, but the snapping shrimp was the most frequently identified individual food item. Mollusks were found in relatively few stomachs (9.0%) and none were identified to species. In the sounds the two major food groups were crustaceans (38.1%) and annelids (34.2%). Fish and fish parts occurred in 19.4% while mollusks were not included in the top 10 items. Mantis shrimp (SquiZZa en2pusa) and snapping shrimp (Alpheus sp.) were the most frequently 291 ingested species. Too few specimens were collected from the beaches and offshore waters to determine food preferences in these sectors. Feeding activity, as related to the number of stomachs containing food, was greatest during spring as 94.7% of the stomachs contained food (Table 148). During summer and fall feeding activity was equal at 86%, while in winter there was a very slight decline to 82.6%. These high percentages indicate that croaker are active feeders through- out the year. Variations are probably a result of food availability rather than feeding activity. There was a slightly higher percentage of stomachs containing food in the sounds (90.6%) than in the creeks (85.7%) (Table 148). Too few specimens were collected from the beaches and offshore waters to draw conclusions for these sectors. Croaker were active feeders at all temperature ranges as over 86.2% of the stomachs collected from each temperature range contained food (Table 50). Peak feeding activity according to lunar phase occurred during the week preceding first quarter through the three days immediately there- after, and during the week leading up to last quarter when over 86.8% of the stomachs contained food (Table 51). Feeding activity declined slightly during the three day period before new and full moon phases when the percentage dropped to 80%. SPOT Spot (Leiostomus xanthurus) are geographically distributed in the Gulf of Mexico from the Rio Grande to south Florida, and on the Atlantic coast from south Florida to Massachusetts (Fischer., 1978). They are commonly found in habitats similar to that of Atlantic croaker, but spot also prefer softer substrates than do croaker. In general, they may be found in concentrations over almost all smooth bottom habitats within the estuaries, and are one of the most widely distributed fish in our estuaries. Spot generally move offshore during colder months, but both adults and juveniles may be found in estuarine waters year round. 292 0 0 0 Table 148. Number and percent of Atlantic cronker, UMIU10i.U.", with stomachs containing lood vvrsus empty stomachs by season and sector for fish collected in Glynn County. Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Tot=a Food Empty Total Food Empty Total No. z No. z NO. No. Z No. % No. % NO. 2 No. % No. Winter 7 77.8 2 22.2 9 100.0 12 92.3 1 7.7 13 100.0 Spring 11 84.6 2 15.4 13 100.0 59 96.7 2 3.3 61 100.0 1 100.0 0 0.0 1 100.0 Sumer so 90.9 5 9.1 55 100.0 64 84.2 12 15.8 76 100.0 1 50.0 1 50.0 2 100.0 Fall 10 71.4 4 28.6 14 100.0 20 95.2 1 4.8 21 100.0 1 100.0 0 0.0 1 100.0 Total 78 85.7 13 14.3 91 100.0 155 90.6 16 9.4 171 100.0 3 75.0 1 25.0 4 100.0 Offshore Combined Sectors Food Emptz Total Food Empty Total No. z MO. z No. z No. % NO. z No. x Winter o 0.0 1 100.0 1 100.0 19 82.6 4 17.4 23 100.0 Spring 71 94.7 4 5.3 75 100.0 Summer 115 86.5 18 13.5 133 100.0 Fall 31 86.1 5 13.9 36 100.0 Total 0 0.0 1 100.0 1 100.0 236 88.4 31 11.6 267 100.0 Movement and Migration From February 13, 1979 through June 23, 1981, 793 spot were tagged and released. Length frequencies of tagged spot in 50 mm length groups are included in Table 149. Lengths(TL) of spot tagged with Howitt tags ranged from 142 to 326 mm, and those tagged with Floy tags ranged from 108 to 249 mm. Length frequencies of spot tagged with each tag type are shown in Table 150. Table 151 lists the length frequencies of tagged spot in 20 mm groups by gear type used for capture. Tagged spot were returned from September 8, 1979 through July 6, 1981. Of 793 tagged, 13 (1.6%) were recaptured and tags returned. Recovery rates, when separated into 50 mm length groups, ranged no higher than 2.1%. The number of spot released and recaptured, time at large, and distance traveled are presented in Table 149. Time at large ranged from 6 to 88 days with an average of 38 days. Distance traveled ranged as far as 118 km with an average of 14.2 km. The overall recovery rate for spot tagged with Howitt tags was 1.7% and with Floy tags was 1.6% (Table 150). Recovery rates, when separated into 50 mm length groups, ranged as high as 1.9% with Howitt tags and 2.1% with Floy. Commercial fishermen were the major source of recoveries, account- ing for 8 (61.5%) of 13 returns. Only 1 (7.7%) return was by a recrea- tional fisherman. Study activities accounted for the remaining four (30.8%) recoveries (Table 11). Recapture length was not obtained for the recreational recapture. Recapture lengths from recoveries by com- mercial fishermen and project personnel using commercial gear ranged from 152 to 226 MM. Sufficient information was obtained on 11 (85%) of the 13 recaptures to determine the estuarine sector and season of capture. Comparison of return rates between the four sectors revealed that the offshore waters produced the highest return rate (Table 14). Two commercial recaptures did not include location of recapture, but these were probably caught offshore as commercial trawling was legal only in offshore waters. If this assumption is true, it would increase the percentage of recaptures 294 Table 149. Number tagged number and percent recaptured, days at large and distance traveled for spot, &,iostomus xanthurus., in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (km) 7 Length Grou2 Tagqed Recaptured Returned Avg. Max. Avg. Max. 101 - 150 154 2 1.3 52 56 44.7 47 151 - 200 380 8 2.1 37 88 12.2 34 201 - 250 250 3 1.2 33 47 39.3 118 251 - 300 8 0 0.0 Total 793 13 1.6 38 88 23.4 118 I/ Distance measured in kilometers from point of release to point of recapture. Table 150. Total number tagged and the return rates for Howitt or Floy tags 'and for tags combined in 50 = length groups for spot, Leioatomua xanthurus, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Numb&r Number Percent 01 (am) Talited Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 125 6 148 2 1.4 154 2 1.3 175 53 1 1.9 327 7 2.1 380 8 2.1 225 163 3 1.8 87 250 3 1.2 275 8 8 325 1 1 Total 231 4 1.7 562 9 1.6 793 13 1.6 0 fik Ah Table 151. Number of spot, Lejostomus xanthurus., tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length l/ Group Gill Net (in)- Trammel Hook/ (mm) 2 2-7/8 3-1/2 4-5/8 Net Seine Trawl Trap Line Totals 110 - - - - 3 1 4 130 57 - 57 150 - - 229 - 230 170 2 - 1 1 149 - 153 190 14 18 - 1 - - 57 - 90 210 20 104 1 - 1 - 26 - 152 230 4 74 - - 2 - 3 2 85 250 - 18 - - 2 - - - 20 270 - 1 - - - - - - 1 290 - - - - - - - - - 310 - - - - - - - - - 330 - 1 - - - - - - 1 Totals 40 216 1 1 6 1 524 3 1 793 I/ Gill net sizes are stretch mesh measurements. from offshore waters to 54%. Creek and sound sectors produced 4 (36.4%) and 2 (18.2%) of the 11 recoveries, respectively. No recoveries were caught in the beach sector. Spring produced the highest return rate with 63.6% of all recoveries (Table 15). Of the 11 spot recoveries, three (27%) were caught in the immediate area of release; eight (73%) were caught within 25 km; two (18.2%) had moved from 26 to 50 km; and one (9.1%) had traveled over 100 km (Table 152). The spot that traveled over 100 km was tagged in September and recaptured in November offshore from Jacksonville, Florida -- a distance of 118 km. As observed in Table 153, the number of recoveries was insufficient to ascertain movement trends within the estuary. Length-Weight Relationship The length-weight relationship for 325 spot, ranging from 120 to 283 Mm and 23 to 276 g, was log W = 3.121 logL -5.096. The correlation coefficient value for length-weight for spot was 0.8973 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male, female, and all spot combined are presented in Table 24. Figure 38 illustrates length-weight relationship for spot. The greatest lengths recorded for male and female Georgia spot were 283 and 263 mm, respectively. The heaviest male and female weighed 276 and 293 g, respectively. Comparison of length-weight relationships for several spot populations are shown in Table 154. Age and Growth Based on a literature review, Barger and Williams (1980) reported that the most frequently applied method for age determination of spot was length-frequency analyses. However, such analyses identified only two age classes. Based on the scale technique, Welsh and Breder (1924) and Pacheco (1962) reported collection of age IV spot in New Jersey and Chesapeake Bay, respectively. Sundararaj (1960) and Pacheco (1962) presented evidence validating the use of scales for age determination of spot in Louisiana and lower Chesapeake Bay, respectively. However, due to faintness of the annual 298 Table 152. Days at large and distance traveled for spot, Leiostomus xanthurus, tagged in Glynn County, Georgia from January 1979 through June 1982. Days At Distance Traveled (km) Large 0 0.1-1 1-5 6-25 26-50 51-100 101-200 Total Percent I - 50 2 - 1 2 2 - 1 8 72. 7 51 - 100 1 - - 2 - - - 3 27.3 Total 3 - 1 4 2 - 1 11 100.0 Percent 27.3 - 9.1 36.3 18.2 - 9.1 100.0 NOTE: Two recoveries did not include date and location of recapture. Table 153. Seasonal -movement of spot, Leiostomus xanthurus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved By Recaptured Tagged Fish Length Group Caught In Area Movement Within Estuary Movement Out Of Estuary Season (mm) Of Release Zreek to Beach Beach To Creek North South Winter 101-150 151-200 1 Total 1 Percent 100.0 Spring 101-150 151-200 1 1 2 1 Total 2 1 3 1 Percent 28.6 14.3 42.8 14.3 Summer 101-150 - - - - - 151-200 1 - 1 Total 1 - 1 Percent 50. 0 - 50.0 Fall 101-150 151-200 1 Total 1 Percent 100.0 - - - Combined Total 2 2 3 3 Percent 18.2 18.2 9.0 27.3 27.3 400-- W= .000008 L3.121 350-- 2 n= 325 r 89 300-- 250 - - 200 150-- 100-- 50 -- 5 10 15 20 25 30 35 40 TOTAL LENGTH (CM) Figure 38. Length-weight relationship of spot, Leiostomus xanthurus, collected in Glynn County, Georgia from January 1979 through June 1982. 301 Table 154. Comparison of total length-weight relationships-for several populations of spot, Leiostomus xanthurus. Length-Weight Weight of Fish (g) Study Location Equation 100 mm 175 mm 250 mm Dawson (1958) South Carolina log W 2.958 logL -4.544 1/ 14 74 212 Dawson (1965) Mississippi and log W 3.071 logL -5.036 13 71 213 Louisiana Present Study Georgia log W 3.121 logL -5.096 14 80 244 Standard lengths converted to total lengths using the formula TL 1.19 SL. 41 41 di rings, Welsh and Breder (1924) and Barger and Johnson (1980) reported difficulty in age determination for spot collected in New Jersey and the Gulf of Mexico. Sundararaj (1960) and Barger and Johnson (1980) pre- sented evidence verifying that otoliths can be used for valid age deter- minations of spot. Pacheco (1962) described the scale annulus as a densely packed, narrow band of circuli associated with-incomplete or broken circuli in the anterior portion of the scale area. These densely packed or interrupted circuli appear as branched, broken, fragmented or terminated circuli. Circuli before and after these dense rings are usually complete and uniform. Scale annuli were also characterized by light cutting over of new circuli in the lateral regions of the scale and formation of new radii. Scale samples from 319 spot ranging from 42 to 283 mm were examined, and 246 (77%) were considered usable for age analyses. Otoliths from these 246 spot were also examined to validate the scale annuli counts. Scale annuli and otolith rings formed simultaneously. Calculation of mean monthly growth of marginal increments indi- cated scale annuli are formed only once annually from late February through early April. Length-square regression analyses on the relationship between fish length and scale radius yielded an r 2value of 0.62 (P < 0.0001), suggesting that back-calculations based on fish length-scale radius would be reliable for estimating fish length at time of annulus for- mation. Empirical and mean back-calculated total lengths at age for spot are shown in Table 155. Table 156 shows the empirical and weighted mean back-calculated lengths for juvenile, male, female, and all spot combined. Table 27 shows length-age equations for male, female, and all spot combined, and Figure 39 illustrates the length-age relation- ships. Rosa Lee's phenomena (Ricker, 1975) was observed in back-calculated ages for spot. It was observed for the first year's growth for three year classes of spot (Table 155). This may be a result of ageing fish 303 Table 155. Mean back-calculated total lengths for spot, Leiostomus xanthurus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Lengths Length Range Mean Length of Successive Scale Rings Age Number at Capture at Capture 1 2 3 41 0 32 42 - 216 161 1 109 125 - 237 191 147 2 94 182 - 255 224 110 203 3 11 210 - 283 242 98 181 219 Weighted Means 128 201 219 Growth Increments 128 73 18 NOTE: Lengths measured in millimeters. Table 156. Number, empirical and back-calculated total lengths, and growth increments by sex and age for spot, Leiostomus xanthurus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Age Sex 1 2 3 Juveniles Number 20 Mean Length at Capture 164 Back-Calculated Length 143 Growth Increment 143 Males Number 40 41 3 C> Mean Length at Capture 197 223 242 Ln Back-Calculated Length 134 203 215 Growth Increment 134 69 12 Females Number 48 53 8 Mean Length at Capture 197 225 242 Back-Calculated Length 121 199 220 Growth Increment 121 78 21 Combined Number 109 84 11 Mean Length at Capture 191 224 242 Back-Calculated Length 128 201 219 Growth Increment 128 73 18 NOTE: Lengths measured in millimeters. 35 A= .000108 L 1.877 30 n= 326 r2= 31 25 z LU _j 20 0 15 10 5 1w + 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 AGE (YEAR) Figure 39. Length-age relationship of spot, Leiostomus xanthurusl$ collected in Glynn County, Georgia. 306 collected immediately after two severe winters. The 1977 and 1978 winters were designated by the Federal Government as "shrimp disasters" and may have produced conditions detrimental to growth and survival of spot. Of 246 spot aged, 159 (65%) were collected during 1979 and 1980, and 221 (90%) were collected from 1979 through 1981. The remaining 25 spot were collected during 1982. The first and second year's growth of most three year old spot occurred concurrently with these severe winters. The same was true for the first year's growth of two year old spot. Therefore, it is assumed that growth of spot was probably stunted during 1977 and 1978, and that the first year's growth for age I spot (147 mm) may be closer to the expected growth rate. Unfortunately, tag returns were insufficient to document growth rates. Ricker (1975) discussed the introduction of an "artificial" Lee's phenomenon into back-calculations of size from annuli measurements. Ricker stated, ". . . if scale annuli are taken as directly proportional to body length in a population where they are actually proportional to length less a constant quantity the calculated first-year growth is always too small and it becomes smaller, the greater the age of fish from which it is calculated." However, the correction factor (Y inter- cept) value of -5.203 derived for the body lengtb-scale radius relation- ML ship was applied as the constant in back-calculation of spot lengths. The results were similar to the lengths shown in Table 155. Therefore, it is assumed that correct techniques were used for spot in back- calculation of successive scale annuli. dl@ Barger and Williams (1980) derived a "compositive growth rate" M, based on six regression equations derived from various age and growth investigations for spot. Their derived hyperbolic function was: Y X A+BX where Y mean total length in millimeters X age in months A 6.89 x 10 ' B 2.20.x 10-' Therefore, Barger and Williams' (1980) compositive growth for 12, 24, and 36 month old spot was 126, 197, and 243 mm, respectively. Their 307 values were similar to back-calculated lengths for Georgia spot (Table 155). Maturity and Spawning During this study, the smallest specimens examined for which sex could be determined through gross examination of gonads were 129 mm for females and 132 mm for males. These specimens were both age I, or in their second year of life. The smallest specimens to exhibit developing gonads (stage III or higher) were 209 mm (age I) for fe- males and 221 mm (age I) for males. music (1974) noted in an earlier study in Georgia that the smallest spot exhibiting advanced gonadal development (stages IV through VI) measured 175 mm TL (6.9 inches) for males and 210 mm (8.3 inches) for females. The ages were not reported for these fish, but from infor- mation collected from this study these fish would be approximately age IT. Apparently, first spawning is generally after fish exceed 170 mm (6.7 inches) as similar sizes have been reported in other areas (Pearson, 1929; Townsend, 1956; and Dawson, 1958). Dawson (1958) also reported that the ma jority of spawning and near-spawning spot in South Carolina are considered to be late two and early three years old fish. No spawning activity was observed for spot during this study, and no advanced stages of gonadal development were collected. Only resting (stage I) or early developing gonads (stages IT and III) were collected (Table 157). All fish collected from salinities <16 O/oo were stage I or "resting stage." All stage IT fish were collected at salinities of 16-30 O/oo while the four stage III females were collected from salin- ities above 26 O/oo in the sounds (Table 158). Furthermore, these stage III females were collected from the sounds in February when. water temperature was less than 150C (Table 159). Welsh and Breder (1924) reported spot spawning in late fall or early winter. Pearson (1929) reported similar fall and winter spawning in the Gulf of Mexico at passes leading to intracoas@al waters from December until March, with peak activity in January and February. 'Be 'also 308 Table 157. Number of spot, Leiostomus xanthurus, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage III IV V VI VII Month F M F M F M F M F M F M F January 1 0 February 6 12 2 1 4 0 March 29 49 April 31 5 C, May 9 3 June 22 16 J-'Ily 9 12 August 23 1 September 9 4 October 10 10 11 5 November December Table 158. Stages of gonadal development for spot, Leioatomus xanthuzw, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Salinity (0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 Totals mulit II Stage -F M -T-m -F R 7-m- -F R -m -F m January I II 1 0 1 0 III-Vil - - - - February I 0 1 1 1 - - 0 1 5 9 6 12 11 2 1 2 1 III 4 0 4 0 IV-Vil - - - - March I 7 5 1 7 21 37 - - 29 49 H-VII - - - - - - - - - - April I 2 0 4 0 1 1 15 4 1 0 8 0 31 5 II-VII - - - - - - - - - - - - - May I 0 1 3 0 3 2 3 0 - - 9 3 June 9 7 13 8 0 1 22 16 II-Vil - - - - - - - - July I I 0 4 6 3 5 1 1 9 12 II-VII - - - - - - - - - - - - - - August I - - - - - - 5 1 - - 18 0 23 1 H-Vil - - - - - - - - - - - - - - September I - - - - - - 4 4 5 0 - - 9 4 H-Vil - - - - - - - - - - - - - - October T - - - - - - 2 4 2 3 6 3 - - 10 10 II 3 1 2 3 6 1 11 5 III-Vil - - - - - - - - November I-VII December I-VII Comb -ined I 2 1 13 7 7 12 63 65 36 25 27 2 148 112 Total 11 - - - - 4 1 2 3 8 2 - - 14 6 III 4 0 4 0 IV-Vil - - - - ti I @ I I I t P 1P V W W Table 159. Stages of gonadal development for spot, Leiostomus xanthurus, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Temperature ( 0C) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Totals (0/00) Stage F M F M F M F M F M F M F M F M 6-10 1 - - 0 1 2 0 2 1 II-Vil 11-15 1- 1 0 3 7 3 4 0 1 0 13 7 II-VII. - - - - - - - - - - - - I - - 1 0 0 7 5 5 1 0 7 12 16-20 11 - - 1 0 - - 3 1 - - 4 1 III-VII - - - - - - - - - - 15 29 18 13 5 2 25 21 - - 63 65 21-25 - - - - - - 2 3 - - 2 3 III-Vil - - - - - - - - - - - - 2 0 2 2 2 7 10 3 20 13 - - 36 25 1 0 6 1 8 2 26-30 111 2 0 2 0 - - 4 0 IV-Vil - - - - - - - - 31-35 1 8 0 4 2 15 0 27 2 II-VII - - - - - - - - 1 3 2 18 34 27 30 34 10 51 36 15 0 148 112 11 1 1 2 0 - - 9 2 2 3 - - 14 6 TOTALS 111 2 0 2 0 - - - - - - - - 4 0 IV-VII - - - - - - - - - - - - - - reported first spawn at,the end of the second year of life, followed by death of the spawners. Fall and winter spawning has been confirmed by workers in other areas (Hildebrand and Schroeder, 1928; Hildebrand and Cable, 1930; Dawson, 1958; Pacheco, 1962; Music, 1974, Mahood et al., 1974; Barger and Williams, 1980; Weinstein and Walters, 1981). Most in- vestigators also agree that spawning takes place at sea with peak spawn- ing from November through February. Pacheco (1962) reported that the fall migration of adults was coincidental with gonadal development. From the occurrence of advanced maturities in Georgia, Music (1974) concluded that spawning begins in October and may continue as late as March, with the peak in November and December. He was unable to collect ripe females, but found two ripe males in November and two spent fe- males in March in Wassaw Sound. Mahood et al. (1974) reported that juvenile spot, averaging 20 to 56 mm TL, were collected in seine samples in Georgia from February through May, with peak abundance in March in the northern section of the state. Postlarval spot were identified in ichthyoplankton samples during January and February (Table 63). These specimens were collected in all three sectors in January, but in February they were concentrated pri- marily in the upper rivers and creeks. Young specimens were collected in 3-meter trawl samples primarily during winter and spring (Table 52). After abundance peaked in spring, their numbers dropped sharply in sum- mer, and none were collected in the fall trawl samples. There was an increase in the abundance of young spot in trawl samples from the beaches upstream to the upper creeks, indicating a definite preference for the upper portion of the estuaries (Table 53). Results from this and other investigatiops suggest that any spawning that takes place.in Georgia's inside waters is in reduced amounts in the northern portion of the coastline. The overall sex ratio of females to males during this study was 1.4:1 (Table 41), and was the same as reported in an earlier study in Georgia by Music (1974). As shown in Table 40, spot exhibiting advanced reproductive stages were virtually absent in collections made in Georgia estuaries 312 which prohibited the determination of fecundity for this species. Food Preference and Feeding Habits Food items identified in spot stomachs by 100 mm length groups are presented in Table 160. Of 321 spot stomachs examined to deter- mine feeding habits, 282 (87.9%) contained food and 39 (12.1%) were empty. Spot are relatively small bottom feeders which consume a wide variety of organisms, most of which are benthic. Small spot <100 mm were found to contain mainly crustaceans and annelid worms. The most frequently occurring crustaceans were copepods, and the most frequently occurring annelids were Reteromastus filiformis and Eteone sp. In spot 101-200 mm crustaceans, primarily amphipods, and a variety of annelid worms and small mollusks were consumed, Spot >201 mm apparently ate every type of crustacean, mollusk and worm they could adequately ingest. The most frequently occurring items, however, were a variety of uniden- tified polychaetes, small mollusks, and crustaceans. Plant detritus and inorganic materials were frequently a significant portion of stomach contents, but were considered incidentally occurring materials resulting from benthic feeding behavior. The 10 most commonly occurring food items found in spot stomachs by season and sector appear in Table 161. Annelid worms, mollusks and crustaceans were the most frequently ingested foods during winter. During spring, annelids were again the most important food but crusta- ceans also ranked high. Mollusks did not appear in the top 10 items. During summer, crustaceans became the dominant food source, but mollusks and annelids were also important. Plant detritus also occurred in many stomachs. The top occurring food items during fall were rhynchcoel worms and crustaceans, primarily amphipods and small mud crabs (Panopeus sp.). In general, any small invertebrate living in the benthic community is highly susceptible to predation by spot. Everything from young horse- shoe crabs to fish were found, but the data indicate a definite preference for polycbaetes and benthic crustaceans. Chao and Musick (1977) found that the dominant foods of spot in Virginia's York River were burrowing polychaetes. Stickney, Taylor and White (1975) found harpacticoid 313 Table 160. Stomach contents of spot, Leicstomus xanthurus, collected in Glynn County, Georgia from Janvarv 1979 through June 1982. Length Group Percent Average Food Item 1-100 101-200 201-300 301-400 Combined Occurrence Z Bolus PISCES Pisces (unidentifiable) 3 6 8 17 6.0 <5 ARTHROPODA Crustacea (unidentifiable) 8 32 50 1 91 32.3 14 Acetes americanus 2 2 0.7 10 Alpheus heterochelis 2 2 0.7 50 Ampelisca aMita 1 3 4 1.4 Amphipoda 6 26 34 66 23.4 10 Anthuridae 3 5 1 9 3.2 <5 Aoridae 2 2 0.7 10 Caprellidae 2 1 3 1.1 <5 Copepoda 10 5 9 1 25 8.9 6 Corophiidae 2 2 4 1.4 17 Corophium sp. 1 1 0.4 <5 Decapoda 5 5 22 1 33 11.7 25 E2-icthonius brasiZiensis 1 1 0.4 10 Et.rypanopeus depressus 2 2 0.7 35 GwMrus sp. 2 2 0.7 35 Hexap:v,.oj;e-,s anguatifr-na 1 1 0.4 10 Isopoda 1 1 0.4 <5 Melitidae 1 1 2 0.7 80 Manoculodes edwardgi 3 3 1.1 30 Mmioe-ulodes tesslatus 1 3 4 1.4 5 Mysidae 11 11 3.9 63 Neopanopeus sayi 1 1 0.4 <5 Ogyrides alphaeroatris 1 1 0.4 <5 Ostracoda 2 2 0.7 5 Pagruyw longicarpue 1 1 0.4 30 Table 160. (continued) Length Group Percent Average Food Item 1-100 101-200 .201-300 301:SnA Combined Occurrence Z Bolus ARTHROPODA (continued) Falaemopze,'es sp. 1 1 0.4 45 Panopeus herbstii 15 15 5.3 10 Penaeus setiferus 2 2 0.7 5 Pinnixa chactopterana 2 2 0.7 <5 @iorceUana sayLzLa 1 1 0.4 50 Portunus gibbesii 2.8 t9 KEFOSTOMATA LimuZus polyphemuB 1 4 5 1.8 <5 HOLLUSCA Hollusca (unidentifiable) 30 59 1 90 31 . 58 0zione cingenda 1 1 0.4 <5 Gastropoda 3 3 1.1 63 Littorina Zittoy-ea 2 2 0.7 25 Mercenaz-ia mercenaria 1 1 0.4 20 Mod-*rlus demisaus 1 1 0.4 <5 ANNELIDA and ASCHEDWIMES Aegothoa sp. 2 2 0.7 <5 Ampharete acutify-ons 4 1 5 1..0 <5 Capitellidae 5 1 7 13 4.6 <5 Cirraculidae 1 1 14 16 5.7 26 Eteone sp. 9 3 12 24 8.5 <5 Exojone sp. 1 1 0.4 <5 Exojone dispar 5 1 6 2.1 <5 Glyceridae 1 3 4 1.4 <5 GZycinde solitar-ia 3 2 5 1.8 <5 Heteromastus filifoyinis to 3 14 27 9.,., 13 Kinorhyncha 1 1 2 0.7 <5 Lumbrineridae, 3 1 3 7 2.5 <5 Table 161. The 10 near frequently occurring food items found in the stomachs of Vote, Le@-toma @thu@, by season and sector for fi.h collected in GLYM County. Georgia from January 1979 through June 1982. 1 Winter Spring S- NO. Percout Average No. percent Average No. Percent Average sector Food Item Stomachs Occurrence 2 Solus- Food it" Stomechs-Occurrence 2 Bol- Food Item Stonarbt. Occur- Z bolum credo Alvalvia 37 56.9 so Unidentified -teri.1 ls 39.5 31 Plant Detricus 16 ".0 43 Nematode 17 26.2 69 Annelid. 14 36.8 11 31-1vi. 11 44.0 71 Unidentified material 16 24.6 44 Cirratulldee, 13 34.2 29 cr,ustaces 7 28.0 3 OrbWLdw a 12.3 20 Nematode 11 28.9 1 A.Phipda 6 24.0 15 AmmalLda 7 10.8 51 4@tiw altemiflom 10 26.3 10 mollusca 5 20.0 60 malroidan 7 10.8 47 Animl ti.sue 9 23.7 27 thynch-1. 4 16.0 25 Splamidam, 7 10.8 6 Splocid" 9 23.7 11 Annelid. 4 16.0 8 Cnwtmm 5 7.7 is Organic materials a 21.1 75 Unidentified material 4 16.0 5 Madionutme op. 5 7.7 10 Nereldam, 7 18.4 17 Portu-, gibb-ii 3 12.0 40 capitolliAme 5 7.7 4 Strebloopio benedi@ti 7 18.4 12 Penaeum, actifem 2 8.0 5 someds Plant detrltw 24 77.4 41 Unidentified material 21 47.7 23 Plant detritum 11 91.7 23 crostacom is 56.1 17 Annelid. 20 45.5 51 Amphipoda 9 75.0 is Ammoll" 15 48.4 43 crustace. 14 31.8 4 Rhyach-oela 7 58.3 3 Awhipo" 12 38.7 11 Soartiw al temiflom 12 27.3 a cr@umtaccm 5 41.7 20 Unidentified material 11 35.5 43 covepoda 12 27.3 1 Ann*lida 5 41.7 6 N@toda 7 22.6 3 Decapoda 10 22.7 24 111valvia 4 33.3 40 COPOPO" 6 19.4 13 Spicoldse 10 22.7 @l Decapoem 4 33.3 a Abdiancetwo op. 3 9.7 5 Nematode 10 22.7 @l Pamopeme op. 3 25.0 37 Sivolvia 3 9.7 13 1bywhocoel. 9 20.5 13 Por,tunue gibbeii 3 25.0 @l Spartim altemiftom 2 6.5 10 Plant detritus 8 18.2 26 Nematode 3 25.0 <1 Wdentified material 7 58.3 41 cruetaces 20 74.1 26 Benches sm Wdionaetwx. 7 58.3 26 Bivolvie is 5S.6 23 Spartiw al miflom 7 58.3 2 Send 14 51.9 25 lervid" 5 41 7 40 Amphipoda, 13 48.1 11 imidoe, 5 41:7 24 Amelida 12 ".4 28 Steone op. 5 41.7 a D-capo" a 29.6 is cmt-" 3 25.0 <1 Unidentified material a 29.6 13 Phyllodocid" 3 25.0 <1 Plant detritue 6 22.2 12 Stmbloepio benedicti 3 25.0 <1 Skynchoccela 6 22.2 5 Gamtrop.da 1 9.3 90 Inorganic material 4 14.8 is Offebo BMW 1 100.0 60 WKE - am - - Uvalvla 1 100.0 10 Ammokins 1 100.0 10 cmtaees 1 100.0 5 ambipod& 1 100.0 5 Orgamic material 1 100.0 5 TOtaLS givalvia Al 42.3 73 Send 43 45.7 29 Plant detritus 33 51.6 3,0 Valdestifted material 27 27.3 44 Annelid. 34 36.2 34 crvatacea 32 50.0 2D Plant detritum 27 27.9 37 4@tiw altemiflom 29 30.9 8 Aivalvis 30 46.6 43 N@tods 24 24.7 37 Spioni4me 24 25.5 13 Aimphipods 28 43.8 14 cnwtac" 24 24.7 16 Cmtwea 22 23.4 3 Anualida 21 32.8 19 AMROII" 23 23.7 6 0-tod. 21 22.3 1 Rhywj@oela 17 26.6 9 AIMPUPO" 14 14.4 20 Nadioeuetm op. 19 20.2 16 send 16 25.0 23 Orblalidde 8 8.2 20 gt-eome op. Is 19.1 3 D-cepoda 14 21.9 15 madiamotwo op. I $.1 4 Plant mt.rial 16 17.0 48 Umid"tified material 13 2D.3 9 Spiamid" a 9.2 6 Rhymboccela 16 17.0 10 pi.@ ? 10.9 3 anon doent- NO SPOCIMMIS Veto CDII-ct-d -Ith food to stoomcbe. t I Tab" 161 - (-tiMmed) Fail Ccblmed Ut.l. No. Percent A-rage no. F*rc"t A-rage See tor Food Itm Stomahe Occurrome 2 Bolus Fwd Itea St-h. Occurreme- 2bolus Creeks Vaidentifid.7terial 7 6 58 52 37.4 77 Plant detrit 7 :316 16 UBm'Id'-"t"M. -te... 42 30.2 38 cras " 4 36.4 0 Plant datritus 32 23.0 33 Uvalvia 3 27 3 70 MewwitW. 29 20 5 1hymbo"al. 3 27:3 5 Amelid. 26 ls:'7 22 mysidso 2 18.2 20 Cruataces 21 15.1 6 2 2 10 Orblatid.. 19 13.7 10 AmPhipods 2 1,::2 @5 Spimid" 16 11.5 9 Atph- sp. 1 9.1 90 Rreldme 14 10.1 32 10011seze 1 9.1 90 Cirratulidw 14 10.1 29 so"amis plast Datritm Is 93.8 33 Plant detrIt- 58 56.3 33 "Is 12 75 2 Cruet 44.7 13 ipoda 11 68:0. 7 A-114. 43 41,7 40 Samid 10 62 5 6 Awhipoda 39 37.9 Jo pwwp- -P. 10 62:5 3 Unidentified mistertal 37 35.9 29 6 C""t"Is 9 56.3 1a Rbywh*c-l- 28 27.2 Vaidentiffed mterW 4 25.0 33 toda 20 19.4 1 6 vbll@ 4 21. 20 copopoda 19 3 M: 23 Spartiw aI terniflom 15 Uttm-lm litto@ 2 12.5 25 Fa-p- P. 14 13.6 11 --j Beacbm =a X/ Crusts- 23 59.0 22 UmidmtIfted material 15 38.5 26 Alwalvia 15 38.5 23 sow 14 35.9 25 A.Phipoda 13 33.3 11 Anow,lids 12 30.8 28 D'apoda 9 20 5 *@tiw aItor"ifl- 1 17:9 1#2 Plant de trlt- 6 15.4 12 lhyuch@la 6 15.4 5 Offshore saw 1 100.0 60 bivalvia 1 100.0 10 Aimaelid. 1 100.0 10 Crustaces I lW.O 5 A,,hI, I 1 100.0 5 Organic asterials 1 100.0 5 Totals Plmt detritus 22 71.0 28 Plast d*tritue 96 34.0 32 Is 15 48 4 1 Unidentified soteriel 94 33 0 33 ta@" 13 41:9 12 crustacas 91 32:3 14 29.1 32 Ampbipoda 13 41.9 5 Ammm,114s 42 usideatifiod mt.rW 11 35 5 4 Bivalvia 79 28 0 58 P-op- ap. 10 32:3 283 Amphl 66 23:4 10 Saud 10 32.3 6 ---,= !50 17.7 @5 12 1 1 1 34 nywhoc- 1 48 11.0 7 Amokell" 4 162:9 23 Spwtim al:ernifZom 36 12.8 S ol,ral@ia 3 9.7 70 D-spoda 33 11.7 21 jL/Now dommotes so speci@ @e -Ilectd @Ith food In at-hs. I copepods to be the dominant food in spot <200 mm SL in Georgia. Sum- maries of food habits for spot are presented in Dawson (1958) and Chao and Musick (1977). Annelid worms and mollusks were the dominant food in the creeks (Table 161). The major food items in the sounds were crustaceans and annelids, while on the beaches crustaceans and mollusks were encountered most often. Of those spot stomachs examined from offshore waters, there was near even distribution of mollusks, annelid worms and crustaceans. However, too few specimens were collected from offshore waters to draw accurate conclusions for this area. Seasonal feeding activity was apparently greatest during spring as 95.9% of the stomachs examined contained food (Table 162). Summer and winter feeding activity were only slightly lower with 88%, and feeding activity was lowest during fall when 75.9% contained food. A definite trend in increased feeding activity was observed between sectors as the percentage of stomachs containing food increased from the creeks (81.3%) to the sounds (93.6%) to the beaches and offshore waters with 100.0% (Table 162). Water temperature apparently did not significantly alter the feeding habits of spot as over 75% of the stomachs examined contained food in all temperature ranges (Table 50). Spot fed actively throughout the lunar month except during the three days preceding and during new moon when only 38.5% of the stomachs examined contained food (Table 51). During all other moon phases over 66.7% con- tained food. Highest feeding activity apparently occurred during the week preceding full moon and the three days before last quarter as all stomachs examined contained food. SOUTHERN KINGFISH Southern kingfish (Menticirrhus conericanus) may be found in most areas along the west Atlantic from Cape Cod to Buenos Aires, Argentina (Fischer, 1978). They generally prefer sand and firm bottom areas in estauries and nearby ocean waters. Juveniles may be found in abundance 318 Table 162. Mimber :ij)d percent of spot, L-cioitoiwia xanlhiava., with stomachs containing food verstis empty stomachs by season and sector for fish collected in Glynn County, Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empty Totar- Food Empty Tota-r- Food Empty Total No. Z No. z No. Z No. z NO. z No. % No. No. % No. 2 Winter 65 83.3 13 16.7 78 100.0 31 100.0 -0 0.0 31 100.0 - - - - Spring 38 100.0- 0 0.0 38 100.0 44 91.7 4 8.3 48 100.0 12 100.0 0 0.0 12 100.0 Summer 25 78.1 7 21.9 32 10Q.0 12 92.3 1 7.7 13 100.0 27 100.0 0 0.0 27 100.0 Fall 11 47.8 12 52.2 23 100.0 16 88.9 2 11.1 18 100.0 - - - - - - Total 139 81.3 32 18.7 171 100.0 103 93.6 7 6.4 110 100.0 39 100.0 0 0.0 39 100.0 Offshore Combined Sectors Food Empty Total Food Empty Total z No. z No. No. Winter 1 100.0 0 0.0 1 100.0 97 88.2 13 11.8 110 100.0 Spring 94 95.9 4 4.1 98 100.0 Summ@r 64 88.9 8 11.1 72@ 100.0 Fall 27 65.9 14 34.1 41. 100.0 Total 1 100.0 0 0.0 1 100.0 282 87.9 39 12.1 321 100.0 year around at all depths in the lower portion of the'estuaries, while the adults move to offshore waters during the colder months. Movement and Migration From March 12, 1979 through June 28, 1982, 540 southern kingfish were tagged and released. Length frequencies of tagged kingfish are presented in 50 mm length groups in Table 163. Lengths (TL) of king- fish tagged with Howitt tags ranged from 146 to 400 mm and those tagged with Floy tags ranged from 116 to 352 mm. Length frequencies of king- fish tagged with each tag type appear in Table 164. Table 165 lists length frequencies of tagged southern kingfish in 20 mm groups by gear type used for capture. Southern kingfish recaptures were returned from August 17, 1979 through September 8, 1982. Of 540 kingfish tagged, 26 (4.8%) were recaptured and tags returned. Recovery rates, when separated into 50 mm fish length groups, ranged as high as 9.2%. The number of fish released and recaptured, time at large, and distance traveled are presented in Table 163. Time at large ranged from 5 to 682 days with an average of 230 days. Distance traveled ranged as far as 537 km, averaging 44.1 km. The overall recovery rate with Howitt tags was 7.5% and with Floy tags was only 0.9% (Table 164). Recovery rates, when separated into 50 mm length groups, ranged as high as 10.9% with Howitt tags and 2.6% with Floy tags. Commercial fishermen were the major source of southern kingfish recoveries, accounting for 15 (57.7%) of 26 returns. The remaining 11 recoveries were caught by recreational fishermen (Table 11). Of 11 recreational recaptures, 9 (82%) included sufficient information to determine lengths of creel size fish. Lengths (TL) of recreational recaptures ranged from 213 to 360 mm with an average size of 299 mm (Table 12). Length frequencies of recaptures indicated that most creel size fish ranged between 250 and 350 mm with the highest percentage (44.5%) between 301 and 350 mm (Table 13). The beaches and offshore areas produced 82% of all recoveries with 36.4 and 45.5%, respectively (Table 14). The creeks produced 320 Table 163. Number tagged, number and percent recaptured, days at large and distance traveled for southern kingfish, Menticirrhus =ericanus, in 50 mm length groups. Number Number Percent Days At Large Distance Traveled (km) Length Group Tagged Reca2tured Returned Avg. Max. Avg. Max. 101 - 150 39 0 0.0 151 - 200 131 2 1.5 128 251 14.8 19 201 - 250 122 8 6.6 192 340 15.2 41 251 - 300 164 9 5.5 214 505 20.4 72 301 - 350 76 7 9.2 324 682 120.4 537 351 - 400 8 0 0.0 Total 540 26 4.8 230 682 44.1 537 l/ Distance measured in kilometers from point of release to point of recapture. Table 164. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for southern kingfish, Menticirrhus CLMericanus, tagged in Glynn County, Georgia from January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Number Number Percent (mm) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 125 2 37 1 39 175 40 1 2.5 91 1 1.1 131 2 1.5 225 83 6 7.2 39 1 2.6 122 7 5.7 275 ill 9 8.1 53 164 9 5.5 325 64 7 10.9 12 76 7 9.2 375 7 1 8 Total 307 23 7.5 233 2 0.9 540 25 4.6 Orl (I ti A Table 165. Number of southern kingf ish, Menticirrhus =ericanus, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Length Group Gill Net (in)-L (MM) 2-7/8 3-1/2 Trammel Net Trawl Hook/Line Totals 1-10 - - - 3 - 3 130 - - 14 - 14 150 - - 36 - 36 170 - - 51 - 51 190 - - 63 3 66 210 1 60 6 68 230 - 28 4 32 250 - 35 9 44 270 - 44 24 68 290 - - 56 74 310 3 1 - 33 6- 43 330 5 - 1 15 2 23 350 1 - 12 1 14 370 - - - 390 2 - - 2 - 4 Totals 13 1 2 452 72 540 I/Gill net sizes are stretch mesh measurements. only one return (4.5%) while the sounds accounted for three (13.6%). Spring produced 54.6% of recoveries while winter and fall produced the fewest with 13.6 and 4.5%, respectively (Table 15). Summer accounted for the remaining six (27.3%) returns. Georgia residents fishing in state waters accounted for 10 (91%) of the 11 recreational recoveries. Of these Georgia fishermen, seven (70%) traveled 40 km or less to reach the location of recapture, and all fisher- men traveled less than 120 km (Table 16). Bait and gear types used by recreational fishermen to catch southern kingfish were available for only nine recaptures. Three specimens were recaptured with seines and one was caught with a gill net in Florida. Gear and bait information were not obtained for two recreational recaptures. Five recreational recaptures were caught with dead shrimp (Table 17). Only 13% of the kingfish recoveries were recaptured in the immediate area of release. Of 23 kingfish for which recapture location was known, 17 (74%) were recaptured within 25 km of the tagging site (Table 166). Three recoveries (13%) had traveled 26 to 50 km, and one recovery was taken from each of the following distance intervals: 51 to 100, 101 to 200, and over 500 km. The specimen that moved over 500 km was at large 682 days and recaptured with a haul seine in March, south of Surf City, North Carolina. This 356 mm specimen -had traveled a distance of 537 km. Winter recoveries produced the greatest movement, averaging 304.8 km (Table 21). Recoveries were insufficient to ascertain movement within the estuary, but movements out of the estuary both north and south were similar during all seasons (Table 167). Length-Weight Relationship The length-weight relationship of 195 southern kingfish, ranging from 90 to 388 mm and 7 to 734 g, was log W = 3.160 logL -5.360. The correlation coefficient value for length-weight was 0.9900 (P < 0.0001). Least-squares regression analyses on the length-weight relationships for male, female, and all southern kingfish combined are shown in Table 24. Figure 40 illustrates length-weight relationships for southern 324 Table 166. Days at large and distance traveled for southern kingfish, Menticirrhus americanus, tagged in Glynn County, Georgia from January 1979 through June 1982. Distance Traveled (km) Days At 51- 101- 201- 301- Over Large 0 0.1-1 1-5 6-25 26-50 100 200 300 500 500 Total Percent 1 - 50 3 - - - - - - - - - 3 13.0 51 - 100 - - - 3 1 - - - - - 4 17.4 101 - 150 - - 2 - - - 1 - - - 3 13.0 151 - 200 - - 2 - - - - - - - 2 8.7 201 - 300 - - - 4 1 - - - - - 5 21.8 301 - 500 - - - 3 1 - - - - - 4 17.5 501 - 750 - - - - - 1 - - - 1 2 8.7 Total 3 - 4 10 3 1 1 - - 1 23 100.0 Percent 13.0 - 17.5 43.6 13.0 4.3 4.3 - - 4.3 100.0 Table 167. Seasonal movement of southern kingfish, Menticirrhus wnericanus, tagged in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Direction Moved By Recaptured TaXited Fish Length Group Caught In Area Movement Within Es Movement Out Of Estuary (mm) MCreek North South Season Of Release Creek to Beach Beacs Winter 151-200 201-250 251-300 1 1 301-350 - - 1 Total 1 1 1 Percent 33.3 33.3 33.3 Spring 151-200 - - - - 201-250 - 1 2 251-300 - 3 2 W 301-350 - 1 1 - N) CY, Total - 1 5 4 Percent - 10.0 50.0 40.0 Summer 151-200 - - 1 1 201-250 1 - - 3 251-300 - - - - 301-350 1 - - 2 6 Total 1 - - 2 6 Percent 11.1 - - 22.2 66.7 Fall 151-200 - - - - - 201-250 - - - 251-300 1 - - 301-350 - - - Total I - - Percent 100.0 - - - - Combined Total 3 1 1 8 10 Percent 13.1 4.3 4.3 34.8 43.5 1000- W= .000005 0-160 875-- 2 n= 195 r 99 750-- 500 CD 375-- 250-- 125-- 5 10 15 20 25 30 35 40 TOTAL LENGTH (CM) Figure 40. Length-weight relation of southern kingfish, Menticirrhus americanus, collected in Glynn County, Georgia from January 1979 through June 1982. 327 kingfish. The greatest lengths recorded for male and female Georgia kingfish were 319 and 388 mm, respectively. The heaviest male was 353 g and the heaviest female was 734 g. @Age and Growth Available information on age and growth of southern kingfish has been based primarily on length-frequency analyses (Welsh and Breder, 1924; Hildebrand and Cable, 1934; Bearden, 1963). Welsh and Breder (1924) also examined scale samples from New Jersey kingfish and found that fish lengths derived from the scale annuli method confirmed their findings based on length-frequency analyses. Scale samples from 215 southern kingfish ranging from 90 to 388 mm were examined, and 187 (87%) were considered legible for age analyses. Otolith sections from these 187 specimens were also examined and year mark formation on otoliths was found to be simultaneous with that of scales. The following scale characteristics were considered to be true annuli: heavy cutting over of circuli in the lateral regions of the scale, formation of new radii, and a narrow band of broken and fragmented circuli in the anterior region of the scale. The calculation of mean monthly growth of marginal increments indi- cated that scale annuli were formed only once annually. Single annulus formation was detectable on scales during March and April, with all scales bearing recent annuli by mid-May. Least-squares regression analyses on the relationship between fish length and scale radius yielded an r2 value of 0.86 (P < 0.0001). Such results suggest the relationship to be sufficiently linear to warrant direct proportion calcul4tions to determine fish length at time of annulus formation. The empirical and mean back-calculated lengths at age for southern kingfish are shown in Table 168. Weighted back-calcu- lated lengths for juvenile, male,. female, and all southern kingfish com- bined are contained in Table 169. Table 27 shows the length-age equations for male, female, and combined southern kingfish, and Figure 41 illus- trates the length-age relationship of all kingfish combined. 328 Table 168. Mean back-calculated total lengths for southern kingfish, Afentic,_'lorhus americanus, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Length Range Mean Length Lengths of Successive Scale Rings Age Number at Capture at Capture 1 2 3 4 0 44 90 - 246 150 1 93 105 - 338 202 145 2 37 230 - 366 208 163 279 3 9 293 - 387 330 173 270 316 4 4 343 - 388 370 159 269 328 361 Weighted Means 152 277 320 361 Growth Increment 152 125 43 41 NOTE: Lengths measured in millimeters. Table 169. Number, empirical and back-calculated total lengths, and growth increments by sex and age for southern kingfish, Menticirrhus americanus, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. A Ae Sex 2 3 4 Juveniles Number 29 1 Mean Length at Capture 146 230 Back-Calculsted Length 131 219 Growth Increment 131 88 Males Number 8 2 2 Mean Length at Capture 179 297 302 Back-Calculated Length 149 234 275 Growth Increment 149 85 41 Females Number 56 34 7 4 Mean Length at Capture 234 311 339 370 Back@Calculated Length 158 282 328 361 Growth Increment 158 124 46 33 Combined Number 93 37 9 4 Mean Length at Capture 202 308 330 370 Back-Calculated Length 152 277 320 361 Growth Increment 152 125 43 41 NOTE: Lengths measured in millimeters. 40 A= .000431 0*533 35 n= 196 r2 .47 30 25 z bi _j 20 0 15 10 5 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 AGE (YEAR) Figure 41. Length-age relationship of southern kingfish, Menticirrhus americanus, collected in Glynn County, Georgia. ,.4 331 Maturity and Spawning The smallest specimens for which sex could be determined through gross examination were 147 mm for females and 142 mm for males. These specimens were age 1, or in their second year of life. The smallest female exhibiting developing ovaries (stage III or greater) was 287 mm (age I). Stage II was the highest level of gonadal development observed in males, occurring in one specimen 293 mm (age III). Bearden (1964) reported that sexual maturity in South Carolina males was reached at 195 mm SL, probably two years old or slightly less, and in females at 230-250 mm SL, or approximately two to three years of age. Southern kingfish are present in Georgia waters the year around, but adults appear in greatest numbers in early spring and are collected throughout the warmer months. The spawning period in Georgia was pre- viously reported as March through August by Mahood et al. (1974). From the maturity data collected during this study it appears that spawning development probably begins in March and continues as late as September, with peak spawning activity during April and May (Table 170). Although very few adults exhibiting advanced stages of gonadal development were collected, -three stage V females were collected inside St. Simons Sound and one stage VI male was collected from the beach. Since no ripe females or males were collected from inside waters, it is probable that the vast majority of adults spawn in ocean waters although some spawning probably also takes place along the beaches and in the lower sounds. Music (per- sonal observation) collected running ripe female southern kingfish approxi- mately six nautical miles offshore from Jekyll Island at night during June in approximately 10 meters of water during experimental trawling for brown shrimp in 1974. Mahood et al. (1974) reported collection of young southern kingfish in the creeks and rivers during seining operations only during July in the southern portion of the state. They also reported that juveniles were more dependent on large rivers and sounds as nursery areas than most other species although they did use the upper creeks and marshes to a limited extent. Table 171 presents the maturity stages by month and salinity gradient. 332 Table 170. Number of southern kingf ish, Menticirrhus americanus, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage IV V VI VII Month F M F F M F M F M F M F M January 5 1 February 4 1 March 24 4 16 1 2 0 April 1 0 2 3 5 0 2 0 0 1 May 8 1 3 0 1 0 June 1 0 4 0 July 18 1 5 0 2 0 August 9 0 1 0 2 0 September 4 0 1 0 1 0 October 3 0 November 5 0 December 9 1 Table 171. Stages of gonadal development for southern kingfish, Menticiy-rhus mner-icanue, by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Salinity-(0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 TOTALS Month Stag4@ F M F M F M F K F M F M January I - - - - - - - - 2 0 3 5 1 11-Vil Februarl 1 3 1 1 0 4 1 11-Vil March I 1 0 - - 3 1 20 3 - - 24 4 2 0 1 1 6 0 7 0 - - 16 1 4- 111 2 0 2 0 IV-VU - - - - April I 1 0 - - 1 0 1 0 0 3 1 0 2 3 1 0 1 0 3 0 5 0 IV - - - - V 2 0 2 0 VI 0 1 - - 0 1 VII - - - - - - Ray 1 6 1 2 U - - 8 1 11 1 0 1 0 1 0 3 0 III IV V 0 0 VI - - VII - June I - - 1 0 1 0 3 0 1 0 4 0 III-VII - - - - - - Table 171. (continued) Surface Water Salinity (0/00) Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 TOTALS Month Stage F M F M F M F F M F F M F M July 1 0 5 0 12 1 18 1 0 4 0 5 1 0 2 U IV-VII August 1 9 0 9 0 1 0 1 0 1 0 1 0 2 0 IV-Vii - - - - w September 1 2 0 1 0 1 0 4 0 w Ii - - - - 1 0 0 t-n 1 0 0 IV-VII - - October I - - 1 0 1 0 1 0 3 0 II-Vil - - - - - - - - - - November 1 2 0 - - 3 0 - - 5 0 II-Vii - - - - - - - - December I - - 4 1 2 0 3 0 9 1 II-Vii - - - - - - - - Combined 1 5 0 19 3 21 2 46 4 - 91 9 Total 11 3 0 2 4 12 0 15 0 - 32 4 111 0 1 0 2 0 4 0 3 0 1 0 - 12 0 IV - - - - - - - - - - - - V 1 0 2 0 3 0 Vi 0 1 - - 0 1 Vil - - - - - All advanced maturity stages were collected at salinities above 21 0 /00 during April and May. Beginning development (stage III) occurred at water temperature above 160C while more advanced stages were collected after water temperature exceeded 210C (Table 172). No correlation could be made between spawning development and lunar phase as too few specimens were collected (Table 40). No larval or ppstlarval southern kingfish were identified in ichthyo- plankton samples (Table 63). However, young specimens were collected in trawl samples throughout the year. The.lowest occurrence of young king- fish occurred during winter, but their numbers increased through spring and peaked in summer before again dropping sharply in fall (Table 52). Young specimens were collected throughout the estuaries but their occur- rence increased steadily from the creeks toward the beaches (Table 53). Hildebrand and Cable (1934) reasoned from the abundance of larvae at Beaufort, North Carolina that the principal spawning season for that area seemed to extend from the latter part of June through July and August. They further concluded that spawning probably occurs chiefly along outside shores although some spawning may take place within inside waters. Bearden (1963) reported that mature specimens with developing roe were found in South Carolina in April and June, and one nearly ripe female was found in July. Therefore, he presumed that spawning takes place largely or entirely offshore since no fully ripe females were col- lected. He concluded that the spawning season in South Carolina extends about the same period of time as was reported by Hildebrand and Cable (1934). Our results seem to follow that of Bearden in that spawning takes place largely or entirely at sea. The sex ratio of female to male southern kingfisb during this study was 10.6:1 (Table 41). As shown in Table 40, southern kingfish exhibiting advanced repro- ductive stages of gonadal development were virtually absent in collections made in Georgia estuaries. This absence prohibited detailed analyses of fecundity. However, fecundity was estimated to be approximately 198,000 eggs for one age 11, 334 mm specimen. The total weight of this fish was 336 t P I I to 4P 0 0 Table 172. Stages of gonadal development for southern kingfish, Mcnticirrhua wwy-icanus, by water temperature and salinity gradients for fish collected in Glynn County. Georgia from January 1979 through June 1982. Surface Water !Merature joc) Salinity Reproductive 0-5 6-10 11-15 -T lb.- =2(--10 31-35 Total@ (0/00) Sta,e F N F N F N D- 5 I-Vil 6-10 1 U IV-VII 11-15 M 1 0 1 0 IV-Vil I 1 0 2 0 5 0 it i 0 3 0 16-20 111 2 0 2 0 IV-Vil - - - - U.) 8 1 2 0 19 3 I 1 0 - - -1 4 1 0 4 0 21-25 IV V 1 0 1 0 VI-Vil I 1 0 4 1 6 1 0 (1 0 21 2 11 - - - 4 0 3 0 5 0 1-1 0 III 1 0 3 0 2&-30 IV V 2 0 2 0 VI - - - - VIT 1 23 3 - - - - 1 7 0 46 4 7 0 - - 2 0 4 0 2 0 15 0 31-35 111 - - - - - - 1 0 - - 1 0 IV-VIl - - - - - - - - - - - - I 1 0 36 6 9 1 12 1 26 1 7 0 91 9 ii 1 0 7 0 7 4 6 0 9 0 2 0 32 4 111 0 4 0 1 0 TOTALS IV - - - - - V 3 0 V1-VII 439 g, with the gonads making up approximately 17% (75.9 g) of its total weight. Food Preference and Feeding Habits Although southern kingfish or "whiting" are relatively small fish with rather small mouths, they are very aggressive and voracious bottom feeders which eat a variety of organisms. Of 226 southern kingfish stomachs examined to determine food preferences and feeding habits, 188 (83.2%) contained food and 38 (16.8%) were empty. Food items identified in stomachs by fish length, in 100 mm groupings, are presented in Table 173. In young kingfish <100 mm small mollusks were the most frequently oc- curring item although crustaceans and annelid worms were also ingested. Crustaceans in stomach contents included amphipods and fiddler crabs, but only Uca minax was identified to species. In specimens 101-300 mm the primary foods were crustaceans, annelid worms and mollusks. This size group also began to utilize fish such as snake eels (Ophichthus ophis) and blackcheeked tonguefish (SynVhurus plagiusa). In specimens >301 mm fish became as important as crustaceans. A variety of fish species were observed in@the stomachs of larger specimens but star drum (SteZlifer @anceolatua) was the only species found in replicate. The most frequently occurring crustacean was the lady crab (OvaZipes oceNatus) although penaeid shrimp and grass shrimp were also important. No mollusks were observed in the stomachs of larger specimens, but annelid worms remained a major food component. The 10 most frequently occurring food items are presented by season and sector in Table 174. Crustaceans were the primary food source in the creeks and rivers, but fish were also ingested. Major crustaceans included blue crabs (CaNinectes sapidus) and mantis shrimp (Squilla sp.). Major fish species included snake eels and blackcheek tonguefish. In the sounds kingfish fed primarily on fish, crustaceans, and annelid worms. Top food items identified were grass shrimp (PaZaemonetes sp.), mantis shrimp, and the small portunid crab (Portunus gibbessii). No specific fish species ranked in the top 10 food items identifed from the sounds. The most commonly occurring food item on the beaches was the commercial white 338 Table 173. Stomach contents of southern kingfish, menticirrhus cvwz-icanu8, collected in Clynn County, Ceorgia from January 1979 through June 1982. Lena h Group (m) Percent Average Food Item 1-100 101-200 201-300 301-400 401-500 501-600 Combined Occurrence % Bolus PISCES Pisces (unidentifiable) 6 17 15 38 20.2 45 Anchoa mitchilli 1 1 0.5 70 AnguilZa rostmta 1 1 0.1 90 W LO Brevoortia tyrannus 1 1 0.5 90 Centroprietia philadelphica 1 1 0.5 <5 Gomthorax op. 1 1 0.1 <5 Ophiohthua ophis I 1 1 3 1.6 90 Paralichthya dentmatus 1 1 0.5 90 Stellifer lanceoZatus 2 2 1.1 70 Symphurus plagiuea 2 1 3 1.6 80 Upophycis regia 1 1 0.5 90 ARTHROPODA Crustacea (unidentifiable) 1 13 12 3 29 15.4 32 Acetes wwrLoanus 6 6 3.2 43 Alpheus heterochelie 1 2 3 1.6 25 Amphipoda 1 5 1 7 3.7 26 Anthuridae I 1 0.1 30 Arenaeus oribrarius I 1 0.1 90 Table 173. (continued) Lemath Group (m) Percent Average Food Itm 1-100 101-200 201-300 301-400 401-500 501-600 Combined Occurrence % Bolus ARTMPODA (continued) Callianaesa atlantica 1 4 5 2.7 65 CaMnectee aapidu8 I I 0.1 90 C@athura poZita I 1 2 1.1 90 D-apoda 12 11 1 24 12.8 48 Diastylidae I 1 0.1 <5 fi@writa tatpoida 2 2 1.1 65 CMmozmw BP. I L 0.1 <5 Haustorlidae 1 1 0.1 10 Sexap-wp-a ang-tif-ne I I 0.1 40 Z_ rqvidne 2 1 1 1 5 2.7 35 Opyrides atphaero8tri-e 2 2 1.1 60 Ovalipes oceZZatus 5 5 2.7 48 OxIfumstylis swithi I I 0.1 <5 Pagume Zongicarpus 1 2 3 1.6 60 Palaamontea ap. 5 2 1 a 4.3 84 Panopeus herbatii 2 7 9 4.8 60 Felumidae, 2 3 1 6 3.2 67 Penaeua setifer@da I is 2 21 11.2 78 Fimii= chaetoptemw I I 0.1 80 Prooellana sayana I I 0.1 50 Portunus ebbeeii 5 5 10 5.3 64 Sesanw mticulatwn I I 0.1 20 Squilla empusa 2 6 1 9 4.8 70 Trac4peneue conetriotus 3 1 1 5 2.7 73 Voa min= I 0.1 <5 ( P I P Table 173. (continued) Length Group (m) Percent Averag,@ Food Item 1-100 101-200 201-300 301-400 401-500 501-600 Combined Occurrence 2 bolu.-, MOLU'SCA Hollusca (unidentifiable) 5 3 1 9 4.8 44 Gastropoda 1 1 2 1.1 90 Nudibranohia 2 2 1.1 t5 Tellinidae 1 1 0.1 5 CEPHALOPODA Lolliguncula brevis I 1 0.1 20 ANNELIDA and ASCHELMENTHES Arabellidae I 1 0.1 50 Capitellidae I 1 0.1 20 Glycindae eoliZaria 1 1 0.1 30 Nematoda. 2 4 1 1 8 4.3 38 Nertidae 1 2 3 1.6 65 Noolea ainplex 2 20 4 1 27 14.4 71 Orbiniidae 1 1 0.1 5 PLANT Detritus 1 1 0.1 so Spartina alterniflora I 1 0.1 20 INORGANIC MATERIAL 1 13 1 4 19 10.1 70 Number of Stomachs: 226 Number and percent of stomachs containing food: 188 (83.2%) Number and percent of empty stomachs: 38 (16.8%) Table 174. The 10 most frequently occurring food items found in the stomachs of southern kingfish, by season and seCLor for fish collected In Glynn County. Georgia from January 1979 through June 1982. Winter Spring Summe-r NO. Percent Average No. Percent Average NO. Pt-rcent Average Sector Food Item Stomachs Occurrence 2 Bolus Fpod Item Stomachs Occurrence % Solis Food Item Stomachs occurrence Z Bolus Creeks NONE Pisces 2 66.7 90 Crustacea 4 50.0 15 Ophichthua ophis 1 33.3 90 Pisces 3 37.5 40 Alpheus sp. 1 33.3 10 Amphipoda 1 12.5 90 Penaeldae 1 12.5 7n Annelids 1 12.5 70 wolluaca 1 12.5 to Sounds Pieces 4 25.0 73 Pisces 6 30.0 68 Decapoda 13 34.2 52 Crustacea 4 25.0 40 Poptunue gibbeeii 4 20.0 5S Pieces 11 28.9 43 Aoetev wwrixmw 3 18.8 53 Amphipoda 4 20.0 53 Squilla onj-:wa 7 18.4 54 "Unidentiflea material 2 12.5 90 Decapoda, 3 15.0 43 Paluownetes sp. 5 13.2 88 Annelids 2 12.3 90 Crust&cea, 3 15.0 40 Annelida 4 10.5 48 Mysidae 2 12.5 35 Annelida 2 10.0 55 Crustacca 4 to.5 40 Nematode 2 12.5 10 Penopeus sp. 2 10.0 55 Portunue gibbesii 3 7.9 43 AnquiLla rostmta 1 6.3 90 Unidentified material 2 10.0 50 Unidentified material 2 5.3 so ovalipco uce I la t4w 1 6.3 90 Pagww longtcaypur. 1 5.0 90 Aivalvia 2 5.3 55 Plant detritus 1 6.3 so Pamlichthys dentitue 1 5.0 90 Panopeun up. 2 5.3 35 U-) -P, beaches Annelids 13 50.0 79 Peneaus &:tij'crus 19 40.4 78 Portww gibboii 2 50.0 55 Unidentified material 7 26.9 74 Places 6 12.8 75 57uilla 'Rt)Usa 1 25.0 91) Crustacea 3 11.5 60 Unidentified material 5 10.6 62 St-ellifer lanceotatun 1 25.0 90 alvalvia 3 11.5 40 Crustacea 5 1D.6 32 aph"ithus ophis 1 25.0 70 Pem:aus sctifeyw 2 7.7 90 Decapods 5 10.6 32 Nematode 2 7.7 70 Panopczw ap. 4 8.5 65 Decapoda 2 7.7 so ovalipcr ",N.-ILatus 4 8.5 38 Amphipods 2 7.7 5 Callianassa qtlant@,,.w 3 6.4 57 Arenaeus cjibrapiuo 1 3.8 90 Pagurtw lonjiCarpu.1 2 4.3 60 Annelids 2 4.3 25 Offshore Dacrita talpoida 2 66.7 65 Ion - - - MWE Crustacea 2 66.7 40 Nematode 2 66.7 5 Arabellidae 1 33.3 50 Unidentified material 1 33.3 20 Totals Annellda 15 33.3 81 Penaeue cetiferuo 19 27.1 78 Pisces 14 28.0 42 Unidentified material 10 22.2 12 Places 14 20.0 74 Decapodia 13 26.0 52 Crustacea 9 20.0 47 Decapoda a 11.4 36 Squilla LwV,uva 8 16.0 59 Newstods 6 13.3 38 Crustacea 8 1.4 35 Crustacea 8 16.0 28 Pisces 4 8.9 73 Unidentified material 7 10.0 59 Palaemonctes sp. 5 10.0 98 Acetes, owz-icanue 3 6.7 53 P-"--us Sir. 6 8.6 62 Portunus gibbesii 5 10.0 48 Sivalvia 3 6.7 40 Portunus gibbeeii 5 7.1 62 aphicht-hus ophis 2 4.0 so Penacke setifems 2 4.4 90 Amphipoda 4 5.7 53 St@-ltifcr tww-culatuc 2 4.0 70 Dwrlta talpoid@ 2 4.4 50 Annelids 4 5.7 40 Penaeldae 2 4.0 55 Decapoda, 2 4.4 50 ovalipee ocellatuft 4 5.7 38 Panopeus sp. 2 4.0 35 'L/MM* dtwtes no specimens were collecte i .1th food In stomach*. 41 d11 di d11 Table 174. (continued) Fall -Combined Total& l1a. Perceat Ave-S I'llea' A,,r.., fteter read Itm stomachm Occurrence x Doh; Food Itew @ttcb. Occurretce 2 so! crew. Crestacft 2 50.0 10 Crustaces 6 40.0 13 Aprhmrms plagiumo 1 25 90 Pie es 5 33.3 60 wti,46at" sapid" 1 25:.' 90 Decapod. 1 6.7 90 -,Willa squsa 1 25.0 90 (7phiAth@ @phie 1 6.7 90 1 25.0 90 C4tli-,W. eapidua 1 6.7 90 Sq.ill. -Vusa 1 6.7 90 symphurus plgiua. 1 6.7 90 Amphlpoda 1 6.7 90 Peneeld- 6 ;0 I I .1 d. l 6. 0 soude piacmm 5 35.7 48 Pieces 26 29.5 54 2k-%T-- .0"trictue 4 26 6 75 Decapod. 16 18.2 51 vee@said_ 3 21:4 70 C-tacea 11 12.5 40 Mat,eld" 2 14.3 55 A... lid. 10 11.4 51 l"Id" 2 14.3 25 P.1.-@_ts P. 74 Ammmvll@ 2 24.3 25 ev@. ': .0 54 C,"tj@ Polito 1 7.1 90 Port- gibbaii 7 8.0 so 101, 11 at 1-tim 1 71 90 Mideattfied -te,i.l 6 6.8 73 U) Wh-- plaviusa 1 7:1 70 7,_4pus @trict_ 5 S.; 72 ,L- pazawem@ewtes op. 1 7.1 70 P.,Op- P. 5 52 Sawb" Cruetwas 2 40 70 P@ setiferus 21 25.6 so A&*t," aimarlaom@ 2 40:00 50 **'- 1 Id . 16 19 5 13 Foommide,m 1 20 .0 90 ftideotifted mat-ial 12 14:6 69 lid& 1 20.0 90 Crustaces 10 12.2 48 p1w." 1 20.0 so Place. 7 8.5 71 D-pod. 7 a-5 37 P_W,P_ P. 4 1 9 5 sivalvis, A 4:9 163 Ovalte Ilatue 4 4.9 38 [email protected]. 4 4.9 35 Off.b." mm Decrita talpoida 2 50.0 65 Crustates 2 so 0 40 Iseeatod. 2 50:0 5 Arabellidee 1 25 .0 so Unidentified sawi.1 1 25.0 20 Total$ plm@ 6 26.1 48 Piece. 38 20.2 58 hookwpe"mus oonstriatue 4 17.4 75 Crustacem, 29 15.4 37 F 14M 4 27 4 75 Annelid. 27 14.4 65 Criestmeas 4 17:4 40 Decapod,_ 24 28.9 49 AmmalLda 3 13.0 40 penaeus ..tiferue 21 11.2 so 41phu- pLagi- 2 .7 so UnIdeatifitd! mterial 19 10.1 68 mareid" 2 :.7 53 P"t@ gibbeaii 10 5 3 55 Aoctes awwriamolue 2 8.7 50 sqwi Ila expuaa 9 4:8 62 mys"ae, 2 8.7 25 pwwp- p. 9 4.8 58 Calummotee, swi,&8 1 4.3 90 pazae,@metes P. 8 4.3 76 vow democee, me, specfeene Wer. collected With food 1. towacks. shrimp (Penaeus setiferus). However, two other crustaceans, the common mud crab (Panopeus sp.) and lady crab (OvaZipes oceallatus), were also important. Annelids, fish, and mollusks were secondary food items in samples collected from the beaches. Although only four stomach samples were collected froin offshore waters, the mole crab (Ernertia talpoida) was found in two of these four specimens. Welsh and Breder (1924) found that the stomach contents of southern kingfish 2.8 to 5.8 cm at Boca Grande, Florida consisted of schizopodus forms (85%), fish (6%), and polychaete worms (2%). In specimens 12-25 cm the major foods were polychaete worms (24%) and shrimp (20%), but crabs were also consumed. They concluded that the southern kingfish diet is equally divided between crustaceans and polychaete worms (possibly Nereius) with occasional slight quantities of small fish. Bearden (1963) looked at the food habits of South Carolina southern kingfish and found that the most frequently occurring food items for all size groups were crustaceans and marine annelid worms (polychaetes). In specimens 15-80 mm SL annelid worms, mysid shrimp, amphipods and shrimp larvae occurred in over 36% of the stomachs. In specimens 81-135 mm major foods were annelid worms and shrimp with over 44% occurrence. How- ever, crabs, amphipods, shrimp larvae and mysid shrimp were also important with over 16.8% occurrence. Specimens 135-200 mm fed mainly on shrimp, annelid worms and crabs, while specimens 201-280 mm fed mainly on shrimp and crabs. Seasonal feeding activity from fall through spring showed near equal food consumption rates with over 84.3% of the stomachs containing food (Table 175). The percentage dropped slightly in summer to 79.4%, but the reason is unknown. Feeding activity was high in all sectors as over 75% of the stomachs in each sector contained food (Table 175). Greatest feeding activity was in the creeks and along the beaches as 88.2% of the stomachs contained food. In the sounds, the percentage was only slightly lower at 78.6%. Although only four specimens were collected from offshore waters, 75% contained food. '1144 Table 175. Ntimber and percent of southern kingfish, Mrn@icir),h-,.: conaricartiv;, with stomachs containing food versus empty stomachs by season and sector for fish collected in Glynn County. Georgia from January 1979 through June 1982. Creeks Sounds Beaches Food Empt Totar- -Food Empty Total Food Empty Total No. z No. % No. % No. % No. % No. % No. z No. % No. % Winter 0 0.0 1 100.0 1 100.0 16 88.9 2 11.1 18 100.0 26 86.7 4 13.3 30 100.0 Spring 3 100.0 0 0.0 3 100.0 20 71.4 8 26.6 28 100.0 47 90.4 5 9.6 52 100.0 Summer 8 88.9 1 11.1 9 100.,0 38 79.2 -10 20.8 48 100.0 4 66.7 2 33.3 6 100.0 Fall 4 100.0 0 0.0 4 100.0 14 77.8 4 22.2 18 100.0 5 100.0 0 0.0 5 100.0 Total 15 88.2 2 11.8 17 100.0 88 78.6 24 21.4 112 100.0 82 88.2 11 11.8 93 100.0 41 Ln Offshore Combined Sectors Food - Empty Total Food Empty Total No. % No. No. 2 No. % No. No. Winter 3 75.0 1 25.0 4 100.0 45 84.9 8 15.1 53 100.0 Spring - - - - - - 70 84.3 13 15.7 83 100.0 Summer 50 79.4 13 20.6 63 100.0 Fall 23 85.2 4 14.8 27 100.0 Total 3 75.0 1 25.0 4 100.0 188 83.2 38 16.8 226 '100.0 Water temperature apparently had little effect on the feeding activity of southern kingfish (Table 50). At temperatures from 11 to 35 0C over 76.9% of the stomachs examined contained food from each temperature gra- dient. Although the percentage dropped slightly to 66.7% at temperatures below 100C, only three specimens were collected and accurate conclusions from such small samples cannot be drawn. In relation to lunar phase, peak feeding activity apparently took place during the three days prior to new moon and during the three day period before las; t quarter as over 91% of the stomachs contained food (Table 51). Lowest feeding activity occurred during the three days fol- lowing new moon, during the three day period after the first quarter, and during full moon when over 24% of the stomachs were empty. Further break- down of feeding activity according to lunar phase is impractical because of low numbers collected during certain lunar phases. GULF KINGFISH The geographical distribution of the gulf kingfish (Menticirrhus Z ZittoraZis) includes the Atlantic coast from south Florida to Chesapeake Bay, the Gulf of Mexico and continental coast of the Caribbean Sea, and the Atlantic coast of South America southward to Rio Grande, Brazil .(Fischer, 1978). Gulf kingfish, also known as beach or surf whiting, prefer smooth sand bottom areas along the beaches and nearshore ocean water s, and they seldom occur inside the estuaries. Movement and Migration Only 10 gulf kingfish were tagged in the estuarine waters of Glynn County, Georgia. Length frequencies in 50 mm length groups are presented in Table 176. Lengths (TL) of gulf kingfish tagged with Howitt tags r@Lnged from 220 to 277 mm and those tagged with Floy tags ranged from 176 to 293 mm. Table 177 lists the length frequencies of gulf kingfish col- lected for tagging in 20 mm groups by gear type. Since none of the 10 tagged gulf kingfish were recovered, recovery information was not available to ascertain movement for this species 346 Table 176. Total number tagged and the return rates for Howitt or Floy tags and for tags combined in 50 mm length groups for gulf kingfish, Menticirrhus Zittoralis, tagged in Glynn County, Georgia frpm. January 1979 through June 1982. Howitt Tag Floy Tag Combined Length Group Number Number Percent Number Number Percent Number Number Percent Imm) Tagged Returned Recaptured Tagged Returned Recaptured Tagged Returned Recaptured 175 1 1 225 1 2 3 275 1 5 6 Total 2 0 0.0 8 0 0.0 10 0 0.0 Table 177. Number of gulf kingf ish, Mel2ticirrhus Zittoralis, tagged by length group and by gear used in capture for fish collected in Glynn County, Georgia from January 1979 through June 1982. Gill Net I/ Length Group (mm) (2 in) Trawl Hook and Line Totals CrI 170 - 1 - 1 190 - - - - 210 - 1 - 1 230 - - - - 250 1 - 2 3 270 2 1 - 3 290 1 1 - 2 Totals 4 4 2 10 Gill net sizes are stretch mesh measurements. (Table 14). However, based on release information, gulf kingfish occur primarily on beaches and in offshore waters during spring, summer, and early fall. Length-Weight Relationship The length-weight relationship for 28 gulf kingfish, ranging from 176 to 298 mm and 51 to 289 g, was log W = 2.872 logL -4.675. The cor- relation coefficient value for length-weight for this species was 0.8054 (P < 0.0001). Least-squares regression analyses of the length-weight relationships for females, males, and all gulf kingfish combined are shown in Table 24. Figure 42 illustrates the length-weight relationships for gulf kingfish. Greatest lengths recorded for males and females were 217 and 298 mm, respectively. The heaviest specimens weighed 117 g for males and 298 g for females. Age and Growth Scales and otolith sections from 34 gulf kingfish ranging from 176 to 298 mm were examined, and 28 (92%) were considered to be legible for age analyses. Scale characteristics described for southern kingfish were similar to that for gulf kingfish and were considered as the criteria for recognition of annuli on gulf kingfish scales. Scale and otolith ring formations were simultaneous. Although the total number of gulf kingfish collected was insufficient to document the number and time of annuli formations., calculations of mean monthly growth of marginal increments indicated that scale annuli were _01 formed only once annually during March through May. Least-squares regression analyses on the relationship between fish length and scale radius yielded an r 2 value of 0.25 (P < 0.0077). Back- calculations of fish length at time of annulus formation were performed, and empirical and mean back-calculated total lengths at age for gulf king- fish are shown in Table 178. Weighted back-calculated lengths for male, female and all kingfish combined are presented in Table 179. 349 400-- W= .000021 L2.872 350-- n= 28 r2= .81 300-- ,250-- CD 200 CD Ld 150-- 100__ 50 -- 1'0 1@ 20 25 30 35 40 TOTAL LENGTH (CM) Figure 42. Length-weight relationship of gulf kingf ish Menticirrhus ZittoraZis, collected in Glynn County,Georgia from January 1979 through June 1982. 350 Table 178. Mean back-calculated total lengths for Gulf king fish, Men ticirrhus ZittoraZis, collected in the coastal waters of Glynn County, Georgia from January 1979 through June 1982. Mean Back-Calculated Lengths Length Range Mean Length of Successive Scale Rings Age Number at Capture at Capture 1 2 0 1 176 176 1 22 214 - 263 236 113 2 5 248 - 298 284 150 266 Weighted Means 120 266 Growth Increments 120 146 NOTE: Lengths measured in millimeters. Table 179. Number, empirical and back-calculated total lengths, and growth increments by sex and age for Gulf kingfish, Menticirrhus Zittoralis-, collected in coastal waters of Glynn County, Georgia from January 1979 through June 1982. Age Sex 1 2 Juveniles Number Mean Length at Capture None Collected Back-Calculated Length Growth Increment Males Number 2 Mean Length at Capture 215 Back-Calculated Length 97 Growth Increment 97 Females Number 20 5 Mean Length at Capture 238 284 Back-Calculated Length 122 266 Growth Increment 122 144 Combined Number 22 5 Mean Length at Capture 236 284 Back-Calculated Length 120 266 Growth Increment 120 146 NOTE: Lengths measured in millimeters. 352 Maturity and Spawning Relatively low numbers of gulf kingfish were collected during the study due to their seasonality and distinct preference for the beaches and surf zone. The smallest specimens for which sex could be determined through gross examination were a 213 mm female and a 214 mm male. Both of these specimens were age 1, or in their second year of life. The smallest female exhibiting developing gonads (stageIII or higher) was a 292 mm specimen (age II). The only male found exhibiting advanced maturity was a 326 mm specimen, and the only ripe female collected was a 292 mm specimen (age 11). Age at maturity was first considered to be in the third or fourth summer (Welsh and Breder, 1924). However, Lunz (1955) later reported that maturity is reached in the second or third year. Bearden (1963) reported that it is possible that sexual maturity for gulf kingfish is similar to that of southern kingfish, which he judged to be probably two years old or slightly less for males and approximately two to three years for females. His assumptions were based on gonadal inspection of both species. Various stages of gonadal development for gulf kingfish are pre- sented by month and sex in Table 180. Of 37 mature specimens collected, 62.2% exhibited "resting stage" gonads while 32.4% were in relatively early stages of development (stages II and III). Only two specimens exhibited advanced maturity. These two specimens were a ripe female and a ripe male which were collected in the surf zone on the beach at Christmas Creek on Cumberland Island in April from water temperature of 200C and salinity of 22 0/oo (Tables 181 and 182). Close proximity to the Satilla River, a major coastal plains freshwater river drainage system, plus normal tidal exchange from Christmas Creek probably accounted for the occurrence of these spawners in relatively low salinity waters. The overall average salinity,along the beaches in Glynn County, Georgia during this survey was 28.8 0/oo (Table 37). Hildebrand and Cable (1934) reported that spawning begins at Beaufort, North Carolina no later than the first of May and continues into August, 353 Table 180. Number of gulf kingf ish, Menticirrhus littoralis, collected by month, sex and reproductive stage for the period January 1979 through June 1982. Reproductive Stage I II III IV V VI VII Month F M F M F M F M F M F M January February March April 2 1 may 3 0 June July August 21 2 6 0 September October November December or, qw Table 181. Stages of gonadal development for Gulf kingfish. Menticirrhus littoraZis. by month, sex and salinity gradient for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Salinity (0100) Reproductive (575 6-10 11-15 16-20 21-25 26-30 31-35 36-40 Totals Month State F M T-M F M F M F M F M F M F M F M January I-VII - - - - - - - - - - - - - - - - - - February I-VII - - - - - - - - - - - - - - - - - - Karch I-Vil - - - - - - - - - - - - - - - - - - April 2 -1 2 1 IV V V1 VII May 1 0 1 0 2 0 III-Vil - - - - - - - - - - - - - - - - June I-Vil - - - - - - - - - - - - - - July I-VII - - - - - - - - - - - - - - August - 21 2 21 2 7 0 7 0 Septenber I-VII October I-VII Nove=ber I-Vil December I-Vil Totals 21 2 21 2 1 0 8 0 9 0 2 1 2 1 IV V VI Vil Table 182. Stages of gonadal development for Gulf kingfish, Menticirrhua littoralis, by water temperature and salinity gradients for fish collected in Glynn County, Georgia from January 1979 through June 1982. Surface Water Temperature (*C) Salinity Reproductive 0-5 6-10 11-15 16-20 21-25 26-30 31-35 Totals (0/00) Stage F M F M F M F M F M F M F M F M 2 1 2 1 21-25 IV V VI VII I 26-30 11 1 0 1 0 iri-vii - - - - I - - 21 2 21 2 31-35 11 0 2 0 5 0 8 0 III-VII - - - - - - - - - - 21 2 21 2 0 3 0 5 0 9 0 2 2 1 TOTALS IV V VI VII and that it seemed almost certain that spawning occurs only in the open outside waters. Their conclusions were based on the rare occurrence of adults in spawning condition in inside waters. Lunz (1955) reported that all three species of kingfish spawn in outside waters in South Carolina with the possibility of some spawning in the sounds. Mahood et al, (1974) reported in a previous trawling and gillnet study along the Georgia coast that gulf kingfish were collected in all months with peak.abundance in March and April. However, they failed to collect young specimens during seining activities in ins Iide waters, and were therefore unable to report a spawning season for this species. Bearden (1963) reported that spawn- ing presumably occurs at the same time in South Carolina as was previously reported by Hildebrand and Cable (1934) for Beaufort, North Carolina. His presumption was based on the collection of a wide size range (25-90 mm SL) of young during the fall. The absence of gulf kingfish exhibiting advanced reproductive stages of gonadal development in Georgia estuaries prohibited detailed analyses of fecundity (Table 40). However, fecundity was estimated to be approxi- mately 216,750 eggs for one age 11, 292 mm specimen. Total weight of this fish was 289 g, and its ovaries comprised approximately 24% (68.3 g) of its total body weight. Food Preference and Feeding Habits The gulf kingfish, or surf whiting, occurs in much lower numbers than the southern kingfish or common whiting. Of 35 gulf kingfish stomachs ex- amined to determine food preferences and feeding habits, 28 (80%) contained food and 7 (20%) were empty. The contents of stomachs containing food are presented by fish size in 100 mm groupings in Table 183. No specimens <100 mm were found with food in their stomachs. Although only two speci- mens 101-200 mm had ingested food, amphipods and bivalve mollusks were found in their stomachs. In specimens 201-300 mm the major foods were annelid worms, mollusks and crustaceans. Mysid shrimp and lady crabs (Ooalipes ocelZatus) were the most frequently occurring crustaceans al- though the small crab (Pinnixa chaetopterana) was also found. The poly- chaete worm (NicoZea simpZex) was the most frequently occurring species 357 Table 183. Stomach contents of gulf kingfish, Menticiry-hus littoralis, collected in Glynn County Georgia from January 1979 through June 1982. Length Group Percent Average Food Item -FOI-200 201-300 301-400 Combined Occurrence % Bolus ARTHROPODA Crustacea 16 1 17 60.7 35 Amphipoda I 1 3.6 70 Decapoda I 1 3.6 10 Haustorildae I 1 3.6 5 Mysidae 2 2 7.1 5 oloalinee occtZatue 2 2 7.1 75 10 rlinnixa chactopterana I I 3.b HOLLUSCA co Mollusca 9 9 32.1 36 Fossor con,@,uina (Donax I 1 3.6 90 variabilis) Bivalvia I 1 3.6 20 Tellinidae I 1 3.6 50 ANNELIDA EunIcIdae I 1 3.6 10 Nicolea simplex 14 14 50.0 46 PLANT DetrItus 1 1 3.6 90 Number of stomachs: 35 Number and percent of stomachs containing foodt. 28 (80.0%) Number and percent of empty stomachs: 7 (20.0%) Am Al& ingested by this size group. Too few specimens were collected for fi sh >301 mm to determine feeding habits, but the small mollusk, Donax variabilis, was found in one specimen. The gulf kingfish occurs seasonally in Georgia, appearing in the spring and peaking in abundance during summer. Consequently, no speci- mens were collected for food habits studies during fall and winter. Furthermore, since it prefers the surf zone along the beaches, no speci- mens were collected from the creeks and sounds. It occurs so infrequently in inland waters that many anglers do not know that there are two species of kingfish in our waters., The 10 most frequently occurring food items ingested by this species are presented by season and sector in Table 184. In general, major foods were crustaceans, annelid worms and mollusks. The most frequently occur- ring crustacean was the lady crab (Ovalipes ocellatus). Although mollusks were ingested, only the'small coquina (Fossor coquina) was identified. During spring, lady crabs@ and mysid shrimp were the most frequently in- gested crustaceans although other crabs (Pinnixa sp.) and digger amphi- pods were also observed (Table 184). Coquina shells were the most commonly occurring mollusk. During summer the main foods were crustaceans, annelid worms, and mollusks. Other items of lower occurrence included amphipods and tellin shells. Insufficient samples of gulf kingfish were collected to correlate water temperature or lunar phase with feeding activities. The data col- lected are presented in Tables 50 and 51. Bearden (1963) found that juvenile gulf kingfish in South Carolina waters had fed almost entirely on beach fleas (Orchestia sp.), and the adults contained fish remains, mole crabs (E@nerita sp.) and stomatopod (SquiZla sp.) remains. MISCELLANEOUS SPECIES In addition to those species selected for this-study, 116 specimens of 11 additional species were tagged in limited numbers. Information on the number released and recaptured, time at large, and distance traveled 359 Table 164. The 10 most froquearly occurring food items found in the stomachs of -Iplf kingfish, Merricirrhuj lit;,Iml'@'e, by season and bv sector for fish collected in Clyan Couv@ty, Georgia from Jsnuary 1979 through June 1982. Winter Spring Summer V.. F7ercoot A"rage 50. Percent Average No. p-c-C Average Sector Food Itow Stomachs Occurrence % bol" Food Item Stomachs Occurrence I bols Food Item Stomachs Occurrence I Sol.. Creeks MMY NONE Sawa" am am - - - *ME - - - M&tb" NOR ovalipee ooellatua 2 50.0 75 Crustaces 16 66.7 31 HyaLd" 2 50.0 5 Annelid. 14 58.3 46 Foesor conquiw 1 Z5.0 90 H.1lusca 9 37.5 35 Crusteces 1 25.0 90 Plant detritus 1 4.2 90 Decapda 1 25.0 10 AWbipoda 1 4.2 70 pimi= p. 1 25.0 10 T.11inadae 1 4.2 50 gmicid- 1 25.0 10 Sivalvia 1 4.2 20 Houstorilds. 1 25.0 <5 Offelm 0 am am - - - YOU - - - Total* am OwZipas ocellatua 2 50.0 75 Crustaces 16 66.7 31 Mysidae, 2 50.0 5 AMWI We 14 58.3 46 Fossor coqui@ 1 25.0 90 peollusce 9 37.5 35 Crust"ea 1 25.0 90 Plant detritus 1 4.2 90 Doespoda 1 25.0 10 Awhipods 1 4.2 70 pinni= op. 1 25.0 LO Tellined" 1 4.2 50 Emnicidas 1 25.0 10 91valvin 1 4.2 20 Haustorlid" 1 25.0 @5 VMmme demotes, no opeclamas war* collected with food in stomachs. Alk AdL dw Table 184. (continued) Fall Combined Totals No. Percent Average NO. Percent Average Sector Food Item Stomachs Occurrence % Bolus Food Item Stomachs Occurrence Z Bolus Creeks NONE NONE Sounds NONE NONE - - - Beaches NONE Crustacea 17 60.7 35 Annelids 14 50.0 46 Molluscs 9 32.1 36 ovalipes ocelZatus 2 7.1 75 Nysidae 2 7.1 5 Plant detritus 1 3.6 90 Fooeor coquina 1 3.6 90 Amphipoda 1 3.6 70 Tellinidae 1 3.6 50 Bivalvia 1 3.6 20 Offshore NONE - NONE - - - Totals NONE - Crustacca 17 60.7 35 Anneli,la 14 50.0 46 Molluscs 9 32.1 36 ovalipe's ocellatus 2 7.1 75 Mysidae 2 7.1 5 Plant detritus 1 3.6 90 Fossor coquina 1 3.6 90 Amphipoda 1 3.6 70 Tellinidae 1 3.6 50 Bivalvia 1 3.6 20 gone denotes no specimens were collected with food In stomachs. for each of these species are presented in Table 185. Of these additional species tagged, individuals of only five species were recovered. One of five tagged Atlantic sturgeon (Acipenser oxyrhynchus) was recaptured. This 610 mm (TL) individual was released in the St. Andrew estuarine system during Ja'nuary and traveled 37 km before being recap- tured six days later by a shad fisherman in the delta portion of the Altamaha River. Thirty-five rock seabass (Centropristis phiZadeZphica) were tagged, but only two (5.7%) were recovered. Both recaptures were released during October in St. Simons Sound and recaptured in ocean waters by commercial shrimp trawlers. One was at large three days and recaptured approximately 12 km offshore from Jekyll Island. The other specimen was at large 18 days and recaptured in the St. Simons Sound channel after traveling 5.5 km. The lengths of these seabass when released were 252 and 262 mm, respectively. One of ten tagged striped mullet (A@ugiZ cephalus) was recaptured. This specimen was released during February in Clubbs Creek in the St. Simons estuarine system and recaptured 393 days later by project personnel in the same area of release. The female mullet measured 290 mm (FL) when released and was 323 mm when recaptured -- a growth of 33 mm. Of five tripletail (Lobotes surincanensis) tagged, only one was re- captured. This individual was released during August in St. Andrew Sound and traveled 490 km before it was recaptured 600 days later by a commercial @for swordfish in the Gulf 'tre' * fisherman longlining S am off Ft. Pierce, Florida. It was gaff ed while lazily swimming underneath a longline buoy. This specimen had measured 462 mm (TL) when released and reportedly measured 34 inches (860 mm) when recaptured -- a growth of 434 mm. The remaining six species tagged did not produce any reported re- coveries. 362 V w w Table 185. Number tagged, number and percent recaptured and days at large and distance traveled for fish tagged in addition to the target species. Number Number Percent Days at Large Distance Traveled (km) Species Tagged Recaptur2d Returned Average Maximum Average Maximum Atlantic sturgeon (Acipenser oxyrhynchus) 5 1 20.0 6 6 37 37 Black sea bass (Centropristis striata) 5 0 0.0 ON Bluefish (Ponkztomue saltatrix) 5 0 0.0 w Florida Pompano (Trachiwtus carolinus) 3 0 0.0 Gray snapper (Lutjanus gy-iaeus) 2 0 0.0 Gulf flounder (Patmlichthyc albigutta) 1 0 0.0 Rock seabass (Centropristis philadeZphica) 35 2 5.7 11 18 9 12 Spotted hake (Urapycis regia) 30 0 0.0 Striped mullet (ftgil cephalus) 10 1 10.0 393 393 0 0 Tripletail (Lobotes surinwnensis) 5 1 20.0 600 600 489 489 Silver seatrout (Cywecion nothus) 15 0 0.0 SUMMARY Spotted seatrout are Georgia's most popular inshore recreational species. Personnel tagged 3,381 seatrout and received 456 (13.5%) re- turns. Recreational fishermen were the major producer of tag recoveries with 68%, while commercial fishermen produced only 0.9%. Movement was seasonal and generally short range, averaging only 8.9 km. Approxi- mately 90% of all recoveries were recaptured within 25 km of the tagging site. Maximum distance traveled was 110 km. Seatrout are generally estuarine specific and in many cases they seem oriented to particular river systems. Recapturelengths ranged from 268 to 735 mm with an average length of 414 mm.* Maximum ages observed were age VIII for females and VI for males. Spawning took place in the lower estuary and along the beaches from April through August, peaking in May and June at water temperatures and salinities above 21 0C and 26 O/oo, respectively. Hermaphroditism was observed in eight specimens, but represented <1% of all specimens examined. Feeding habits changed with increase in size from smaller crustaceans to penaeid shrimp to predominantly fish in the largest specimens. Weakfish or "summer trout" rank moderately as a recreational fish species and are generally taken by bottom fishermen. Only 48 (1.6%) of the 2,958 tagged weakfish were returned and recreational fishermen accounted for only 17 (35.4%) recoveries. Most (54.5%) creel-sized recoveries ranged from 350 to 500 mm, and 95% (43) of the recoveries were recaptured within 25 km of the tagging site. Average and maximum distances traveled were 8.3 and 167 km, respectively. Most,spawning activity apparently took place in ocean waters, but advanced maturities were collected in the lower portions of St. Simons Sound with peak occurrence in April, when 29.4% of the females exhibited advanced ovarian development. PreferTed foods for smaller weakfish (<200 mm) were crustaceans and anchovies, but larger specimens showed a definite preference for menhaden and penaeid shrimp. 364 Red drum or "channel bass" are very popular with anglers, but population size is relatively small in comparison with species such as spotted seatrout, croaker and weakfish. Only 368 red drum were tagged, but 79 (21.5%) were recaptured, indicating very high fishing pressure on the first four year classes. Return rates for individual size groups ranged as high as 28.9%, Average movement was 14.2 km, and 88.6% of the recoveries were caught within 25 km of the tagging site. Maximum distance traveled was 178 km. Creel lengths of re- captures ranged from 311 to 659 mm, averaging 447 mm.. Spawning ap- parently took place at sea during fall and early winter when adults left the surf zone and moved seaward. No advanced gonadal development was observed. Smal.l. red drum (<200 no) ate primarily crustaceans. . However, as they increased in size (301 - 800 mm) fish were also incor- porated into the diet. Of 1,181 southern flounder tagged, only 75 (6.4%) were recaptured, indicating that this species is probably underharvested by recreational anglers. Anglers caught only 41 (54.7%) of the recaptures. Maximum distance traveled was 556 km, and average distance was 53.8 km. Lengths of recreational recaptures ranged 222 - 436 mm, averaging 340 mm. Spawn- ing apparently occurred in ocean waters during fall and early winter as only one specimen with developing gonads was collected in inshore waters. Small southern flounder (<200 mm) ate both fish and crustaceans, but larger creel size specimens showed a definite preference,for fish. The population of creel size summer flounder in Georgia's coastal waters is very small. Of 141 summer flounder tagged, only 1. (0.7%) was recaptured. This particular specimen was caught by a commercial shrimp trawler in ocean waters. Of 23 summer flounder aged, only one specimen had formed an annulus, indicating that fish over age I generally move out of the estuaries. Only three mature females were collected, and these exhibited resting (stage 1) ovaries. Small summer flounder fed predominantly on crustaceans, but specimens 201 - 300 mm also fed on squid. ,04 Of 352 black drum tagged, 92 (26.1%) were recaptured.. Maximum 365 distance traveled was 619 km and average distance was 41.2 km. Approxi- mately 84% of the recoveries were collected within 25 km of the tagging site. Lengths of recreational recoveries ranged from 251 to 400 mm. Spawning took place primarily during March and April at salinities >21 0/oo and temperatures 16 - 25 0C. Small drum fed mainly on decapod crustaceans and annelid worms (polychaetes), but mollusks became impor- tant with increase in size. The largest adults preferred crabs and bivalve mollusks. Of 416 sheepshead tagged,,only 30 (7.2%) were recaptured, indicating low fishing pressure. Returns were only from recreational fishermen (76.7%) and project personnel (23.3%). Movement was generally short range as 93% (28) of the returns were captured within 25 km of the tagging site. Recapture lengths ranged 192 - 393 mm, averaging 300 mm. Spawning activity was apparently centered in offshore waters from March through May as no spawning activity was observed in inland waters. Little difference existed in the diet of different size groups except for a greater inclusion of-mollusks, echinoderms and urochordates with increase in size. Crustaceans and mollusks were the staple food source for all size groups. Croaker had a very low return rate as only 2.5% (87) of the 3,456 tagged specimens were recaptured. Approximately 48% of the recaptures were recaptured in the immediate area of release, and 92% were caught within 25 km. Maximum movement was 179 km and average movement was 10.9 km. Lengths of recreational recaptures ranged from 200 - 300 Em. Apparently, most croaker over one to two years of age moved out of the estuaries. Spawning activity probably extended from August to April, with the peak during September and October. Advanced maturity was observed at temperatures <28 0C and salinity >16 0/oo. Small croaker (<200 mm) fed mainly on crustaceans and annelid worms (polychaetes), and the largest specimens included limited amounts of fish in their diets. Spot ranked very low as a recreational 8pe6ies. Of 793 tagged, only 13 (1.6%) were recovered, and only one Q.7%) of these was taken by a recreational fisherman. Movement averaged 14.2 km with a-maximum 366 distance of 118 km. No spawning activity was observed in inland waters, and spawning apparently took place in ocean waters during late fall and winter. Primary foods were annelid worms, mollusks and crustaceans, but most small invertebrates were susceptible to ingestion. Only 26 (4.8%) of the 540 tagged southern kingfish were recovered. Average distance traveled was 44.1 km, although one specimen traveled 537 km. Approximately 74% of all recoveries were recaptured within 25 km of the tagging site. Commercial fishermen accounted for 57.7% of the recoveries. Spawning development apparently began in March and continued through September with the peak in late spring. Most spawning apparently took place in ocean waters although some spawning activity may have occurred in the lower sounds. Small southern kingfish fed on small mollusks, crustaceans and annelid worms, but fish also became important in larger specimens. Gulf kingfish were collected seasonally during warm months. Only 10 specimens were tagged, and no recoveries were obtained. Spawning information was limited, but spawning activity apparently took place at sea during spring and summer. Annelid worms, mollusks and crusta- ceans were found in stomach contents. 367 RECOMMENDATIONS To insure that wise and prudent management decisions relative to Georgia's marine recreational fishery will be made in the future, con- sideration should be given to the following recommendations: 1. Establish a daily creel limit of two (2) red drum per person, and a possession limit of four (4) per person for red drum measuring over thirty (30) inches total length. This recommendation is proposed to insure adequate protection of spawning size red drum from overexploitation. Reported catches of adult reds have apparently declined during the past decade. Since the adults tend to congregate in relatively few areas of the surf zone, they are highly suscep- tible to overexploitation. Also, since large speci- mens rank relatively low in palatability due to course textured and strong flavored flesh, such pro- tective measures will be beneficial in preventing wanton waste of these potential spawners. Furthermore, market values for adult reds are so low in comparison with other species that fishermen making large catches generally have no ready market and often have to give them away. 1 2. Establish a minimum size limit of@twelve (12) inches total length for the minimum creel length,of red drum. The growth rate for this species is so rapid,that young specimens en- tering the hook and line fishery for the first time in mid-summer at approximately 10 inches length will be approx'l- mately 12 inches long by September. This measure basically gives these fish two more growing months by letting them reach.12 inches. Furthermore, many of these undersized fish that will be released as a result of this measure will be 368 recaptured the next season at a much larger size of approximately 20 inches or three pounds. Such a minimum size limit will help create a higher total yield per recruit for this species. Furthermore, those small red drum that are not recaptured a second time could possibly survive to serve as brood stock at a later date. 3. Establish a continuing standardized finfish monitoring program for the major inshore recreational fish species to determine current population levels and evaluate future population trends. Such a data base would estab- lish catch per unit effort values that can be linked with recreational fishery statistics to determine fishing pres- sure on individual stocks so that practical management strategies can be practiced. 4. Continue life history studies on red drum with special emphasis on the reproductive biology. This would entail expanding the study area to include Georgia's oceanic waters as it is assumed that this is the location of most spawning activity. 5. Conduct a comprehensive marine recreational fishery survey of coastal Georgia to determine the extent, value and rela- tive fishing pressure being exerted by the marine recrea- tional fishery. This initial survey would establish a data base that will be used for comparison of future periodic surveys to determine trends in the recreational fishery as well as fishing pressure being exerted on indi- vidual fish populations. Such information is absolutely necessary for proper management of Georgia's recreational fishery. 6. Continue the status quo regarding commercial gillnetting activity in Georgia. This would include prohibiting any additional gillnetting activities in Georgia's coastal 369 waters. At present, gillnetting is not allowed for any fish species other than shad and sturgeon during the commercial season opened specifically for these species. From the strong evidence of territorality in spotted seatrout, the estuarine dependence and general lack of movement of red drum <4 years of age, and from the,apparently already depleted population of red drum in Georgia's coastal waters, it is highly probable that increased gillnetting activity would have an adverse impact on these two most popular inshore fish species. Georgia's sounds are relatively small in relation to the much larger sounds and bays of other states where gillnetting is legal. Gillnetting in Georgia could or quickly result in overfishing of these recreationally important inshore species. Gillnetting activities would be focused on the @horeline oyster beds currently being targeted by recreational anglers, resulting in conflicts between the two.user groups. Several states with legal- ized gillnetting,are,currently faced with the problem of managing depleted fish stocks -- attributed to over- fishing, and trying to resolve conflicts between commer- cial and recreational user groups. Management strategies have generally resulted in allocation of the resources between the user &oups. Hopefully, if Georgia-maintains the status quo this will not be a problem and recreational fishermen can continue to enjoy top quality fishing. 370 ACKNOWLEDGMENTS We wish to express our appreciation to Helen D. Walker (Laboratory Technician) and Karl David Herrin (Field Technician) for invaluable service and assistance during the course of this study. We would also like to a,cknowledge,Anthony "Tony" Reisinger who served as a project biologist during the first year of the study. Other supporting personnel involved in both field and laboratory activities included: Karen Baxley, Karen Bunt Varnedoe, Sherri Boone, Randy Bellflower and Milledge Smith. We would also like to express our appreciation to Eleanor Waters (Librar- ian) for valuable library assistance; to Ron Essig (Chief of Data Manage- ment Section) for help in processing and retrieving data via computer services; to Susan Shipman (Chief of Coastal Fisheries) for editorial review and comments on this manuscript; and to Libby Waldron and Debbie Bellflower for typing this manuscript. 371 LITERATURE CITED Adkins, G., and M. J. Bourgeois. 1982. An evaluation of gill nets of various mesh sizes. La. Dept. Wildl. Fish. Tech. Bull. 36, 59 p. Adkins, G., J. Tarver, P. Bowman and B. Savoie. 1979. A study of the commercial finfish in coastal Louisiana. La. Dept. Wildl. Fish. Tech. Bull. 29, 87 p. Arnold, C. R., W. H. Bailey, T. D. Williams, A. Johnson and J. L. Lasswell. 1979. Laboratory spawning and larval rearing of red drum and southern flounder. Proc. Annu. Conf. Southeast. Assoc. Fish Wildl. Agencies, 31:437-440. Arnold, C. R., J. L. Lasswell, W. H. Bailey, T. D. Williams and W. A. Fable, Jr. 1978. Methods and techniques for spawning and rearing spotted seatrout in the laboratory. Proc. 30th Annu. Conf. Southeast. Assoc. Game and Fish Comm., p. 167-178. Arnoldi, D. C., W. H. Herke and E. J. Clairain., Jr. 1974. Estimate of growth rate and length of stay in a marsh nursery of juvenile Atlantic croaker, Micropogon unduZatus (Linnaeus), "sandblasted" with fluorescent pigments. Proc. Gulf & Carib. Fish. Inst., 26th Annu. Sess., New Orleans, La., October 1973, p. 158-172. Bagenal, T. 1978. Methods for assessment of fish production in fresh waters. Blackwell Scientific Publs., Ltd., Oxford, England, 365 p. Barger, L. E., and A. G. Johnson. 1980. An evaluation of marks on hardparts for age determination of Atlantic croaker, spot, sand seatrout, and silver seatrout. V.S. Dept. Commer., Nat'l. @tar. Fish. Serv., S.E. Fish. Center, NOAA Tech. Memo-22, 5 p. Bass, R. J., and J. W. Avault, Jr. 1975. Food habits, length-weight relationship, condition factor, and growth of juvenile red drum, Sciaenops oceZZata, in Louisiana. Trans. Amer. Fish. Soc. 104(l): 35-45. Bearden, C. M. 1963. A contribution to the biology of the king whitings, genus Menticirrhus, of South Carolina. Bears Bluff Lab. Contrib. Ser. 38, 27 p. Bearden, C. M. 1964. Distribution and abundance of Atlantic croaker, Wcropogon unduZatus, in South Carolina. Bears Bluff Lab. Contrib. Ser. 40, 23 p. Beaumariage, D. S. 1964. Returns from the 1963 Schlitz tagging program. Fla. Bd. Conserv. Tech. Ser. 43, 34 p. 372 Beaumariage, D. S. 1969. Returns from the 1965 Schlitz tagging program including a cumulative analysis of previous results. Fla. Dept. Nat. Res., Mar. Res. Lab., Tech. Ser. 59, 38 p. Beaumariage, D. S., and A. C. Wittich. 1966. Returns from the 1964 Schlitz tagging program. Fla. Bd. Conserv. Tech. Ser. 47, 51 p. Bennett, J. T., G. W. Boehlert and K. K. Turekian. 1982. Confirmation of longevity in Sebastes diptoproa (Pisces: Scorpaenidae) from 21 'Pb/22 'Ra measurements in otoliths. Mar. Biol. 71:209-215. Bigelow, H. B., and W. W. Welsh. 1925. Fishes of the Gulf of Maine. Bull. U.S. Bur. Fish. (1924), Vol. 40(Pt. 1), 567 p. Boothby, R. N., and J. W. Avault, Jr. 1971. Food habits, length-weight relationship, and condition factor of the red drum, Sciaenops ocelZata, in southeastern Louisiana. Trans. Amer. Fish. Soc. 100(2):290-295. Bortone, S. A., and Charles L. Hollingsworth. 1980. Ageing red snapper, Lutjanus carripechanus, with otoliths, scales, and vertebrae. Northeast Gulf Sci., 4(l):60-63. Breuer, J. P. 1957. An ecological survey of Baffin and Alazan Bays, Texas. Publ. Inst. Mar. Sci., Univ. Tex. 4(2):134-155. Broadhead, G. C. 1958. Growth of the black mullet (MqiZ cephaZus L.) in west and northwest Florida. Fla. Bd. Conserv. Tech. Ser. 25, 29 p. Brown, N. J. 1981. Reproductive biology and recreational fishery for spotted seatrout, Cynoscion nebuZosus, in the Chesapeake Bay area. Master's Thesis. College of William and Mary, Williamsburg, Va., 120 p. Bruger, G. B. 1981. Comparison of internal anchor tags and Floy FT-68 dart tags for tagging snook, Centropomus undecimaZis. Northeast Gulf Sci., 4(2):119-122. Chao, L. N., and J. A. Musick. 1977. Life history, feeding habits, and functional morphology of juvenile sciaenid fishes in the York River estuary, Virginia. Fish. Bull. 75(4):657-702. Chilton, D. E., and R. J. Beamish. 1982. Age determination methods for fishes studied by the groundfish program at the Pacific Biological Station. Can. Spec. Publ. Fish. Aquat. Sci. 60: 102 p. Colura, R. 1974. Fish propagation. In: Saltwater pond research, study No. 2. Completion Rep., P.L. 88-309 Project 2-169-R. Tex. Parks Wildl. Dept., 32 p. Creel, M., and R. C. Divita. 1982. The occurrence of Penaeus spp. in the stomachs of trawl-caught fishes from the northwestern Gulf of Mexico, 1981. U.S. Dept. Commer., Nat'l. Mar. Fish. Serv., S.E. Fish. Center, NOAA Tech. Memo. 87, 19 p. 373 Dahlberg, M. D. 1976. Guide to coastal fishes of Georgia and nearby states. Univ. Ga. Pr., Athens, 187 p. Dawson, C. E. 1958. A study of the biology and life history of the. spot, Leiostomus xanthurus Lacepede, with special reference to South Carolina. Bears Bluff Lab. Rep. No. 28, 48 p. Dawson, C. E. 1965. Length-weight relationships of some Gulf of Mexico fishes. Trans. Amer. Fish. Soc. 94(3):279-280. DeCiechomski, J. D. 1981. Food utilization by juveniles of some sciaenid fish from coastal waters off Argentina. Rapp. P.-v- R6un. Cons. int. Explor. Mer, 178:389-392. Divita, R., M. Creel, B. Bowling and C. Chester. 1981. pig(@stion rates on penaeid shrimp. U.S. Dept. Commer., Nat'l. Mar. Fish. Serv., Galveston Lab., Spec. Rep. to Lab. Dir., 6 p. Eldridge, P. J. 1962. Observations on the winter trawl fishery for summer flounder, ParaZichthys dentatus. Master's thesis. College of Willian and Mary, Williamsburg, Va., 55,p. Fischer, W. Editor. 1978. FAD species identification sheets for fishery purposes. FAO, UN, Rome, Vols. I-VII. Fontenot, B. J., Jr., and H. E. Rogillio. 1970. A study of estuarine sportfishes in the Biloxi marsh complex, Louisiana. La. Dept. Wildl. Fish., Fish. Bull. No. 8, 172 p. Frisbie, C. M. 1961. Young black drum, Pogonias cromis, in tidal fresh and brackish waters, especially in the Chesapeake and Delaware Bay areas. Chesapeake Sci. 2(1-2):94-100. Ginsburg, 1. 1952. Flounders of the genus ParaZichthys and related genera in American waters. Bull. U.S. Bur. Fish. 52:267-351. Guest, W. C., and G. Gunter. 1958. The seatrout or weakfishes (genus C@noscion) of the Gulf of Mexico. Gulf States Mar. Fish. Comm., Tech. Summ. No. 1, 40 P. Gunter, G. 1945.. Studies on marine fishes of Texas. Publ. Inst. Mar. Sci. Univ. Tex. 1:1-190. Hansen, D. J. 1970. Food, growth, migration, reproduction, and abundance of pinfish, Lagodon rhomboides, and Atlantic croaker, Micropogon unduZatus, near Pensacola, Florida, 1963-65. U.S. Fish & Wildl. Serv. Fish. Bull. 68(l):135-146. Haven, D. S. 1957. Distribution, growth, and availability of juvenile croaker, Micropogon und@Zatus, in Virginia. Ecology 38:88-97. Haven, D. S. 1959. Migration of the croaker, Micropogon unduZatus. Copeia 1959(l):25-37. 374 Hein, S., C. Dugas and J. Shepard. 1980. Total-length standard- length and length-weight regressions for spotted seatrout, Cynoscion nebuZosus; red drum, Sciaenops oceNata, black drum, Pogonias cromis, in south-central Louisiana. La. Dept. Wildl. Fish. Tech. Bull. 31, p. 41-48. Hein, S. H., and J. Shepard. 1979. Spawning of spotted seatrout in a Louisiana estuarine ecosystem. Proc. Annu. Conf. Southeast Assoc. Fish Wildl. Agencies 33:451-465. Henderson, E. M. 1979. Summer flounder (ParaZichthys dentatus) in the northwest Atlantic. Woods Hole Lab. Ref. No. 79-31, 13 p. Herke, W. H. 1971. Use of natural, and semi-impounded, Louisiana tidal marshes as nurseries for fishes and crustaceans. Ph.D. Dissertation.. Louisiana State University, Baton Rouge. 264 p. Univ. Microfilms, Ann Arbor, Mich. (Diss. Abstr. 32:2654-2658). Cited in: Arnoldi, D. C., W. H. Herke an;d E. J. Clairain, Jr. 1974. Estimate of growth rate and length of stay in a marsh nursery of juvenile Atlantic croaker, Micropogon unduZatus (Linnaeus), "sandblasted" with fluo- rescent pigments. Proc. Gulf & Carib. Fish. Inst., 26th Annu. Sess., New Orleans, La., October 1973, p. 158-172. Hildebrand, S. F., and L. E. Cable. 1930. Development and life history of fourteen teleostean fishes at Beaufort, North Carolina. Bull. U.S. Bur. Fish. 46:383-488. Hildebrand, S. F., and L. E. Cable. 1934. Reproduction and development of whitings or kingfishes, drums, spot, croaker, and weakfishes or seatrouts, family Sciaenidae, of the Atlantic coast of the United States. Bull. U.S. Bur. Fish. 48:41-117. Hildebrand, S. F., and L. E. Cable. 1938. Further notes on the develop- ment and life history of some teleosts at Beaufort, N.C. Bull. U.S. Bur. Fish. 48:505-642. Hildebrand, S. F., and W. C. Schroeder. 1928. Fishes of Chesapeake Bay. Bull. U.S. Bur. Fish. 43:1-366. Hilwig, J. T., and K. A. Council. Editors. 1979. SAS user's guide, 1979 edition. SAS Institute Inc., Raleigh, N.C., 494 p. Hofstede, A. E. 1974. Studies on growth, ageing and back-calculation of roach RutiZus rutiZus (L.), and dace Leuciscus Zeuciscus (L.). In: Proceedings of an International Symposium on the Ageing of Fish, edited by T. B. Bagenal. Univ. Reading, England. Unwin Bros. Ltd., Surrey, England, p. 137-147. Ingle, R. M., R. F. Hutton and R. W. Topp. 1962. Results of the tagging of salt water fishes in Florida. Fla. Bd. Conserv. Tech. Ser. 38, 57 p. 375 Iversen, E. S., and D. C. Tabb. 1962. Subpopulations based on growth and tagging studies of spotted seatrout, Cyno.scion n.ebuTosus in Florida. Copeia 1962(3):544-548. Johnson, A. G., W. A. Fable, Jr., T. D. Williams and C. R. Arnold. 1977. Description of reared eggs and young larvae of the red drum, Sciaenops oceUata. In: Marine Fish Propagation Study, Federal Aid Project F-31-R, Completion Rep., Tex. Parks Wildl. Dept. p. 118-127. Johnson, A. S., H. 0. Hillestad, S. F. Shanholtzer and G. F. Shanholtzer. 1974. An ecological survey of the coastal region of Georgia. Nat'l. Park Serv., Sci. Monogr. Ser. 3, U.S. Gov't. Prntg. Ofc., Wash., D. C., 233 p. Kemp, R. J. 1949. Report on stomach analysis on June 1, 1949 through August 31, 1949. Tex. Game, Fish & Oyster Comm., Mar. Lab. Annu. Rep. (1948-1949), p. 101-127. Klima, E. F., and D. C. Tabb. 1959. A contribution to the biology of the spotted weakfish, Cynoscion nebuZosus (Cuvier), from northwest Florida with a description of the fishery. Fla. Bd. Conser-v. Tech. Ser. 30, 24 p. Langton, R. W., and R. E. Bowman. 1981. Food of eight northwest Atlantic pleuronectiform fishes. U.S. Dept. Commer., NOAA, Tech. Rep., Spec. Sci. Rep.-Fish. 749, 16 p. Lassuy, D. R. 1983. Species profiles: Life histories and environmental requirements (Gulf of Mexico)--spotted seatrout. U.S. Fish & Wildl. Serv., Div. Biol. Serv. FWS/OBS-82/11.4. U.S. Army Corps Engrs., TR EL-82-4. 14 p. Lassuy, D. R. 1983. Species profiles: Life histories and environmental requirements (Gulf of Mexico)--Atlantic croaker. U.S. Fish & Wildl. Serv., Div. Biol. Serv. FWSIOBS-82111.3. U.S. Army Corps Engrs., TR EL-82-4. 12 p. I Laswell, J. L., B. W. Lyons and W. H. Bailey. 1978. Hormone-induced spawning of southern flounder. Progr. Fish-Cult. 40(4):154. Lehman, B. A. 1953. Fecundity of Hudson River shad. U.S. Fish & Wildl. Serv., Res. Rep. 33, 8 p. Lorio, W. J., and W. S. Perret. 1980. Biology and ecology of the spotted seatrout (aynoscion nebuZosus). In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm.,'Ocean Springs, Miss., Report No. 5, p. 7-13. Lorio, W. J., and H. E. Schafer. 1966. A food habit study of the spotted seatrout, Cynoscion nebuZosus, in the Biloxi marsh area, Louisiana. Proc. 19th Annu. Conf. Southeast. Assoc. Game and Fish Comm., p. 289-296. 376 Lunz, G. R. 1955. Notes on life history of the common sports fish compiled from literature and unpublished records at Bears Bluff Laboratories. Bears Bluff Lab. Unpublished. 4 p. Lux, F. E. 1971. Age determination of fishes. U.S. Dept. Commer., NOAA, Nat'l. Mar. Fish. Serv. Leaflet 637, 7 p. Mahood, R. K. 1974. Seatrout of the genus Cynoscion in coastal waters of Georgia. Ga. Dept. Nat. Res., Brunswick, Contrib. Ser. 26, 36 p. Mahood, R. K. 1976. Spotted seatrout in coastal waters of Georgia. Proc. 29th Annu. Conf. Southeast. Assoc. Game and Fish. Comm., p. 195-207. Mahood, R. K., C. D. Harris, J. L. Music and B. A. Palmer. 1974. Survey of the fisheries resources in Georgia's estuarine and inshore ocean waters. Part IV. Coastal Georgia - southern, central and northern section. Ga. Dept. Nat. Res., Game & Fish Div., Coastal Fish. Ofc., Brunswick, Contrib. Ser. 25, 201 p. Marcello, R. A., Jr., and R. K. Strawn. 1972. The cage culture of some marine fishes in the intake and discharge of a steam-electric generating station, Galveston Bay, Texas. Tex. A&M Univ. TAMU-SG-72-306, 207 p. Massmann, W. H. 1963a. Annulus formation of the scales of weakfish, Cynoscion regalis, of Chesapeake Bay. Chesapeake Sci. 4:54-56. Massmann, W. H. 1963b. Age and size composition of weakfish, Cynoscion regaZis, from pound nets in Chesapeake Bay, Virginia 1954-1958. Chesapeake Sci. 4:43-51. Matlock, G. C., and J. E. Weaver. 1979. Fish tagging in Texas bays during November 1975 - September 1976. Tex. Parks Wildl. Dept., Coastal Fish. Br., Mgt. Data Ser. No. 1, 136 p. McClane, A. J. Editor. 1965. McClane's standard fishing encyclope- dia and international angling guide. Holt, Rinehart & Winston, New York, N.Y., 1057 p. McHugh, J. L. 1980. History and management of weakfish fisheries. In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm., Ocean Springs, Miss., Report No. 5, p. 63-70. Merriner, J. V. 1976. Aspects of the reproductive biology of the weakfish, Cynoscion regaZis (Sciaenidae), in North Carolina. Fish. Bull. 74:18-26. Miles, D. W. 1950. The life histories of the spotted seatrout, 10 Cynoscion nebuZosus and the redfish, Sciaenops oceZZatus. Tex. Came, Fish & Oyster Comm., Mar. Lab. Annu. Rep. (1949-1950), p. 66-103. 377 Miles, D. W. 1951. The life histories of the seatrout, Cynoscion nebuZosus, and the redfish, Sciaenops ocelZatus. Sexual develop- ment. Tex. Game & Fish Comm., Mar. Lab. Annu. Rep. (1950-1951), P. Miller, E. E. 1966. Age and growth determinations. In: Inland fisheries management, edited by Alex Calhoun. State of California. The Resources Agency, Dept. Fish and Game, p. 57-69. Moffett, A. W. 1961. Movements and growth of spotted seatrout, Cynoscion nebulosus (Cuvier), in west Florida. Fla. Bd. Con serv. Mar. Res. Lab., Tech. Ser. 36, 35 p. Moody, W. D. 1950. A study of the natural history of spotted seatrout, Cynoscion nebuZosus, in the Cedar Key, Florida area. Quart. J. Fla. Acad. Sci. 1,2(3):147-171. Mook, D. 1977. Larval and osteological development of the sheepshead, Archosargus probatocephaZus (Pisces: Sparidae). Copeia 1977(l): 126-133. Music, J. L., Jr. 1974. Observations of the spot (Leiostomus xanthurus) in Georgia's estuarine and close inshore ocean waters. Ga. Dept. Nat. Res., Game & Fish Div., Coastal Fish. Ofc., Brunswick, Contrib. Ser. 28, 29 p. Music, J. L., Jr. 1979. Assessment of Georgia's shrimp and crab resources. Ga. Dept. Nat. Res., Coastal Res. Div., Brunswick, Contrib. Ser. 30, 75 p. Music, J. L., Jr., and J. M. Pafford. 1982. Georgia's bait industry. In: Proceedings of the Marine Natural Bait Industry Workshop, August 24-25, 1981, Charleston, S.C., edited by S. M. Muniak and R. J. Rhodes. S.C. Sea Grant Consortium. Sea Grant Publ. SCSG- PR-82-01, p. 23-36. Overstreet, R. M. 1978. Food of the Atlantic croaker, Micropogonias unduZatus, from Mississippi Sound and the Gulf of Mexico. Gulf Res. Reps. 6(2):145-152. Overstreet, R. M. 1983. Aspects of the biology of the spotted sea- trout, Cynoscion nebuZosus, in Mississippi. Gulf Res. Reps. Suppl. 1:1-43. Overstreet, R. M. 1983. Aspects of the biology of the red drum, Sciaenops oceZZatus, in Mississippi. Gulf Res. Reps. Suppl. 1: 45-68. Overstreet, R. M., and R. W. Heard. 1982. Food contents of six c'ommer- cial fishes from Mississippi Sound. Gulf Res. Reps. 7(2):137-149. 378 Pacheco, A. L. 1962. Age and growth of spot in lower Chesapeake Bay, with notes on distribution and abundance of juveniles in the York River system. Chesapeake Sci. 3(l):18-28. Pafford, J. M. 1983. Life history aspects of the striped mullet, MqiZ cephaZus, in Georgia's St. Simons estuarine system. Master's thesis. Georgia Southern College, Statesboro, Ga. 80 p. Pannella, C. 1974. Otolith growth patterns: an aid in age determina- tion in temperate and tropical fishes. In: Proceedings of an Inter- national Symposium on the Ageing of Fish, edited by T. B. Bagenal. Univ. Reading, England. Unwin Bros. Ltd., Surrey, England, p. 28-39. Pearson, J. C. 1929. Natural history and conservation of the redfish and other commercial sciaenids of the Texas coast. Bull. U.S. Bur. Fish. 44:129-214. Perret, W. S., J. E. Weaver, R. 0. Williams, P. L. Johansen, T. D. McIlwain, R. C. Raulerson and W. M. Tatum. 1980. Fishery profiles of red drum and spotted seatrout. Gulf States Mar. Fish. Comm. Rep. No. 6, 60 p. Poole, J. C. 1961. Age and growth of the fluke in Great South Bay and their significance to the sport fishery. New York Fish & Game Jour., 8(l):1-18. Powell, A. B. 1974. Biology of the summer flounder, ParaZich-bhys dentatus, in Pamlico Sound and adjacent waters, with comments on P. Zethostigma and P. aZbigutta. Master's thesis. Univ. of North Carolina, Chapel Hill, N.C. 145 p. Powell, A. B., and F. J. Schwartz. 1979. Food of ParaZichthys dentatus and P. Zethostigma (Pisces: Bothidae) in North Carolina estuaries. Estuaries 2(4):276-279. Rathbun, R. 1892. Successful hatching of sheepshead eggs on Fish Hawk. Report U.S. Commissioner Fish & Fish. for 1888-1889, p. LIX. Richards, C. E. 1973. Age, growth and distribution of black drum (Pogonias cromis) in Virginia. Trans. Amer. Fish. Soc. 102(3): 584-590. Ricker, W. E. 1975. Computation and interpretation of biological statistics of fish populations. Bull. Fish. Res. Bd. Can. 191, 382 p. Ricker, W. E., and D. Merriman. 1945. On the methods of measuring fish. Copeia 1945(4):184-191. Rohr, B. A. 1980. Use of hard parts to age Gulf of Mexico red drum (Abstract). In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm., Ocean Springs, Miss., Report No. 5, p. 15. 379 Ross, J. L., J. S. Pavela and M. E. Chittenden, Jr. 1983. Seasonal occurrence of black drum, Pogonias cromis, and red drum, Sciaenops cceNatus, off Texas. Northeast Gulf Sci., 6(l):67-70. Seagle, J. H. 1969. Food habits of spotted seatrout (Cynoscion nebuZosus, Cuvier) frequenting turtle grass (ThaZassia testudinum, Konig) beds in Redfish Bay, Texas. Taius 2(l):1-6. Shephard, G. 1980. A comparative study of ageing methods for summer flounder (ParaZichthys dentatus). Woods Hole Lab. Ref. No. 80-13, 10 P. Shipman, S., V. Baisden and H. Ansley. 1983. Studies and assessment of Georgia's marine fisheries resources 1977-1981. Ga. Dept. Nat. Res., Coastal Resources Div., Brunswick. Completion Report to NOAA. Project No. 2-319-R. 513 p. Silverman, M. J. 1979. Biological and fisheries data on black drum, Pogonias cromis (Linnaeus). U.S. Dept. Commer., Nat'l. Mar. Fish. Serv., N.E. Fish. Center, NOAA Tech. Ser. 22, 35 p. Simmons, E. G. 1951. Fish trap investigation. Tex. Came & Fish Comm., Mar. Lab. Annu. Rep. (1951-1951), 23 p. Simmons, E. G., and J. P. Breuer. 1962. A study of redfish, Sciaenops oceNata Linnaeus, and black drum, Pogonias cromis Linnaeus. Publ. Inst. Mar. Sci. Univ. Tex., 8:184-211. Smith, R. W. 1969. An analysis of the summer flounder, ParaZichthys dentatus (Linnaeus), population in the Delaware Bay. Master's thesis. University of Delaware, Newark. 72 p. Smith, R. W., and F. C. Daiber. 1977. Biology of the summer flounder, ParaZichthys dentatus, in Delaware Bay. Fish. Bull. 75(4):823-830. Smith, R. W., L. M. Dery, P. G. Scarlett and A. Jearld, Jr. 1981. Proceedings of the summer flounder (ParaZichthys dentatus) age and growth workshop, 20-21 May 1980, Northeast Fisheries.Center, Woods Hole, Massachusetts. U.S. Dept. Comer., Nat'l. Mar. Fish. Serv. N.E. Fish. Center, NOAA Tech. Memo.' NMFS-F/NEC-11, 30 p. Spinner, G. P. 1969. A plan for the marine kesources of t-he Atlantic coastal zone. Published in conjunction with,Folio 18,, "Tile wild- life wetlands and shellfish areas of the Atlantic coastal zone." Amer. Geographical Soc., Serial Atlas of t@e Marine Environment, 80 p. Stewart, K. W. 1961. Contribution to the biology of the spotted sea- trout (Cynoscion nebuZosus) in the Everglades National Park, Florida. Master's thesis. Univ. Miami, Coral Gables, Fla., 103 p. Stickney, R. R.9 G. L. Taylor and D. B. White. 1975. Food habits of five species of young southeastern United States estuarine Sciaenidae. Chesapeake Sci. 16(2):104-114. 380 Stokes, G. M. 1977. Life history studies of southern flounder (ParaZichthys Zethostigma) and Gulf flounder (P. aZbigutta) in the Aransas Bay area of Texas. Tex. Parks Wildl. Dept. Tech. Ser. 25, 37 p. Street, M. W. 1969. Fecundity of the hickory shad in the Altamaha River, Georgia. Ga. Game & Fish Comm., Brunswick, Contrib. Ser. 14, 11 p. Sundararaj, B. 1. 1960. Age and growth of the spot, Leiostomus xanthurus Lacepede. T.ulane Stud. Zool. 8:40-62. Sundararaj, B. I., and R. D. Suttkus. 1962. Fecundity of the spotted seatrout, Cynoscion nebuZosus (Cuvier), from Lake Borgne area, Louisiana. Trans. Amer. Fish. Soc. 91(l):84-88. Suttkus, R. D. 1955. Seasonal movements and growth of the Atlantic croaker (Micropogon unduZatus) along the east Louisiana coast. Proc. Gulf & Carib. Fish. Inst., 7th Annu. Sess., Havana, Cuba, November 1954, p. 151-158. Tabb, D. C. 1958. Difference in the estuarine ecology of Florida waters and their effect on populations of the spotted weakfish (Cynoscion nebuZosus (Cuvier). Trans. 23rd No. Amer. Wildl. Conf., p. 392-401. Tabb, D. C. 1961. A contribution to the biology of the spotted sea- trout, Cynoscion nebuZosus (Cuvier), of east-central Florida. Fla. Bd. Conserv., Mar. Res. Lab., Tech. Ser. 35, 22 p. Taniguchi, A. K. 1980. Effects of salinity, temperature'and food abundance upon survival of spotted seatrout eggs and larvae. (Abstract). In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm., Ocean Springs, Miss., Report No. 5, p. 16. Theiling, D. L. 1974. Age and growth and attempts at induced spawning of red drum in a salt water marsh impoundment in South Carolina. Master's thesis. Clemson Univ., Clemson, S.C., 31 p. Theiling, D. L., and H. A. Loyacano, Jr. 1976. Age and growth of red drum from a saltwater marsh impoundment in South Carolina. Trans. Amer. Fish. Soc. 105(l):41-44. Thomas, D. L. 1971. The early life history and ecology of six species of drum (Sciaenidae) in the lower Delaware River, a brackish tidal estuary. Ichthyol. Assoc. Bull. 3, 247 p. Topp, R. W. 1963. The tagging of fishes in Florida, 1962 program. Fla. Bd. Conserv., Mar. Lab., Prof. Pap. Ser. No. 5, 76 p. Townsend, B. C., Jr. 1956. A study of the spot, Leiostonus xanthurus Lacepede, in Alligator Harbor, Florida. Master's thesis. Fla. St. Univ., Tallahassee, Fla., 43 p. 381 Wallace, D. H. 1940. Sexual development of the croaker, Micropogon unduZatus, and distribution of the early stages in Chesapeake Bay. Trans. Amer. Fish. Soc. 70:475-482. Weinstein, M. P., and M. P. Walters. 1981. Growth, survival and pro- duction in young-of-year populations of Leiostomus xanthums Lacepede residing in tidal creeks. Estuaries 4(3):185-197. Welsh, W. W., and C. M. Breder, Jr. 1924. Contributions to life histories of Sciaenidae of the eastern United States coast. Bull. U.S. Bur. Fish. 39:141-201. White, M. L., and M. E. Chittenden, Jr. 1977. Age determination, reproduction and population dynamics of the Atlantic croaker, Alicropogonias unduZatus. Fish Bull. 75(l):109-123. Wilk, S. J. 1979. Biological and fisheries data on weakfish, cynoscion regaZis (Bloch and Schneider). U.S. Dept. Commer., Nat'l. Mar. Fish. Serv., N.E. Fish. Center, NOAA Tech. Ser. 21, 49 p. Wilk, S. J. 1980. Biology and ecology of the weakfish, Cynoscion regalis (Bloch and Schneider). In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm., Ocean Springs, Miss., Report No. 5, p. 19-31. William, T., and B. C. Bedford. 1974. The use of otoliths for age determination. In: Proceedings of an International Symposium on the Ageing of Fish, edited by T. B. Bagenal. Univ. Reading, England. Unwin Bros. Ltd., Surrey, England, p. 114-123. Yokel, B. J. 1980. A contribution to the biology and distribution of the red drum, Sciaenops oceZlata. (Abstract). In: Proceedings of the Red Drum and Seatrout Colloquium, Oct. 19-20, 1978. Gulf States Mar. Fish. Comm.', Ocean Springs, Miss., Report No. 5, p. 5. 382 DATE DUE GAYLORD No. 2333 PRINTED IN U SA I @l 7ii