[From the U.S. Government Printing Office, www.gpo.gov]
Coastal Zone Information center A SURVEY OF THE FISH RESOURCES OF SAIPAN LAGOON Steven S. Amesbury, Den-nis R. Lassuy@, Robert F. Myers and Vaughan Tynclzik 77- OK 7 41 J@ @4 r. UNIVERSITY OF GUAM MARINE LABORATORY 0 rd 0 QL co I 636,5 Q) S25 Technical Report No. 52 0 w S87 c3 Cn March 1979 This report was prepared for the Coastal Resources Management program, Executive Office of the Governor, Commonwealth of the Northern Mariana Islands, under a grant from the Office of Coastal Zone Management, National Oceanic and Atmospheric Admi- nistration, Department of Commerce, under the Coastal Zone Management Act of 1972, as amended. A SURVEY OF THE FISH RESOURCES OF SAIPAN LAGOON By Steven S. Amesbury, Dennis R. Lassuy, Robert F. Myers, and Vaughan Tyndzik Prepared for Office of Coastal Zone Management Commonwealth of the Northern Mariana Islands IUS DePartment Of COMmerce NOAA Coastal Services Center Library 2234 South Hob son Avenue Oc Charleston, SC 20405-2413 As per CONTRACT NO. S79-02 University of Guam Marine Laboratory Technical Report No. 52 March 1979' T4BLE OF CONTENTS Page INTRODUCTION 1 Purpose I Scope of Work 2 Acknowledgements 2 METHODS 4 RESULTS AND DISCUSSION 5 Fish Habitats in the Saipan Lagoon Study Area- 5 Distribution and Abundance of Fishes of Potential. Economic Importance 9 Equilibrium Yields of Exploitable Fish Populations 13 Fish Species Diversity 14 Distribution of Fish Larvae and Eggs 15 CONCLUSIONS AND RECOMMENDATIONS 17 Planning and Habitat Protection 17 Estimates of Equilibrium Yields 19 LITERATURE CITED 21 TABLE,S 23 FIGURES 43 PLATES 44 MAPS 58 INTRODUCTION PURPOSE The fish resources of tropical island reefs have historically pro- vided island inhabitants with much of their protein food supply. As island economies undergo a process of westernization, and imported foodstuffs become more available and more heavily utilized, the impor- tance of reef fish resources is often overlooked. Shoreline develop- ments which involve release of effluent materials onto the reef or dredging and filling of marine habitats are frequently designed and undertaken without sufficient understanding of their potential impacts on reef fish populations. Recently there has developed a greater appreciation of the importance of reef fishery potential among planners and administrators of many tropical island communities, and the need for information upon which informed decisions can be made has been felt. One of the major difficulties in understanding the dynamics of reef fish populations and in developing effective management policies has been the great variety of fish species present in tropical reefs, and the variety of habitats for fish which reefs provide. Classical approaches to fishery management have been developed over many years in temperate and boreal continental shelf environments where habitats are more or less uniform over great expanses and where a relatively small number of species are exploited. The long periods of time and the considerable financial investment that have gone into research on these temper-ate and boreal fish stocks is not available to fisheries management in tropical islands. Johannes (in press) has articulated the need for rapid and inexpensive methods of fish stock assessment in the tropics and has pioneered some methodology for achieving these goals. The research described in this report is another approach to the problem of fisheries management in tropical islands. Saipan Lagoon is a typical high-island barrier reef lagoon. It covers an area of approximately 35 million m2 and contains a variety of habitat types. A study of the geology and sediment distribution within the lagoon was prepared by Cloud (1959). Doty and Marsh (1977) carried out a detailed, year-long environmental study of the area surrounding the power barge Impedence. Fish distributions within their study area were investigated, but management of fishery stocks was not addressed. The approach of the present study has been to determine the dis- tribution and abundance of resource fishes among the various habitats within Saipan Lagoon. The average "turn-over time" for the various fish groups has been estimated from published studies, and this information is used to estimate annual harvest potential for the lagoon as a whole. Plankton tows have been used to dtermine areas of,fish egg and larvae concentrations, indications of fish breeding and nursery grounds. Planners can use the information in this report to aid them in locating potentially deleterious activities, such as dredging, filling, and waste disposal, in areas where damage to highly productive or unique environ- ments will be minimized. Fisheries managers can use the estimates of harvest potential to make best use of underutilized resources and, if necessary, to take steps to protect overharvested fish resources. SCOPE OF WORK The investigations reported herein were carried out under contract no. S79-02 with the Coastal Zone Management Program of the Government of the Northern Mariana Islands. We were requested to provide the following services: A.- Conduct surveys of the lagoon to count and identify fish species and populations. To the extent possible, the fish surveys should be coordinated with other studies on algae, marine invertebrates, and corals in the lagoon. B. Prepare a list of species found, their locations, relative abundance, and any other relevant factors. C. Provide a map showing survey locations and generalized distribution of fishes. D. Conduct a field survey of the abundance and distribution of the eggs and larvae of fishes to identify areas of possible importance as breeding grounds and nursery areas. E. Conduct fish surveys and areas which have been damaged through destructive fishing practices (e.g. chlorox, dynamite) and other areas of particular concern identified by the CZM coordinator. F. Insofar as is possible, provide information on the potential fish yield of the various areas surveyed and recommendations for protection of habitats and endangered species at all stages of their life cycles. ACKNOWLEDGEMENTS This project was supported by the Coastal Zone Management Program of the Government of the Northern Mariana Islands. We are grateful to Ms. Martha McCart, CZM Coordinator, and to Ivan Groom, Dave Bortz, and Jerry Maier for their logistics support. The project would not have been successful without the help of Mr. Joaquin Villagomez, Acting Chief, Division of Marine Resources Development, who provided our boat transportation and in many ways Iwas very helpful to us . We would also 2 like to thank Mr. Mike Gawel of the Trust Territory Department of Plann- ing who helped us in the field on his days off. Dr. L. G. Eldredge and Mr. R. H. Randall made their data on Saipan Lagoon available to us and helped us interpret the aerial photographs of the study area. Ms. Terry Balajadia spent many houfs typing the manuscript, and we thank her for that. METHODS The Saipan Lagoon surveys were carried out from January 2 to 8 and January 24 to 29, 1979. Fish censuses were performed in the following manner. Twenty-four habitats within the lagoon and on the seaward side of the lagoon barrier reef were censused. At each location, three investigators swam through the water with snorkeling or scuba gear, as appropriate, making two 10-minute counts of 22 categories of potentially economically important fishes (see Results Section for categories). After the two 10-minute counts, another 10 to 20 minutes were spent by each investigator in making as complete a list as possible of all fish species in the habitat. The six 10-minute counts from each habitat were averagbd. By swimming a measured line at approximately the same speed that the censuses had been swum, and estimating the distance over which the various categories of fishes could be recognized, we deter- mined the average area covered by a 10-minute census to be 2,000 m2. From these data we were ab le to estimate the density per m2 of each category of fish in each habitat type. By examining aerial photographs of the lagoon, consulting the map produced by Cloud (1959), and using our own field information and photographs, we mapped the 24 lagoon habitats. A planimeter (Keoffel and Esser Company) was used to measure the area of each habitat on the map, and this was converted to actual area in m2. With this data we were able to compute the estimated total number of fish of each category in each habitat. Summing all the habitats gave us an estimate of the total number of fishes in each category for the whole lagoon study area. In order to locate areas of fish spawning and nursery areas for larval fishes, we made 17 horizontal surface tows in various parts of the lagoon (Figure 1) with a 50 cm diameter conical zooplankton. net with mesh size of .35 mm. Tows were 5 minutes in duration (Table 4). and were made at a speed of approximately 1 m/sec. Each tow, then, sampled about 59 m3 of water. All tows were made in the daytime. Samples were preserved in 5-10% formalin and returned to the laboratory where counts were made of the various planktonic organisms in the samples (subsampling was done on some large samples). From these data we were able to calculate density per m3 of fish eggs, fish larvae, and other zooplankters in the lagoon waters. 4 RESULTS AND DISCUSSION FISH HABITATS IN THE SAIPAN LAGOON STUDY ARFA Twenty four habitats were designated within the study area .(Maps la-e). In the listing below, the habitats are described and the occurrence of economically valuable fishes within them is summarized. Detailed density estimates for fish categories within each habitat are given in Table 1. Habitat-. 1 -- (Plate 1A) This consisted of a single small embayment east of Chai@Tfe Dock which was surrounded by mangrove trees, the only area of mangrove growth in the lagoon. The water was shallow, approxi- mately 0.5 M, and the substrate was fine silt. An inflow of fresh water could be detected, and visibility was poor, less than two m. Few fishes of any kind were seen here, but it was the only area wher,e mullets were seen during the censuses counts, although there were incidental sight- ing of mullet in habitats 3 and 23. Habitat 1 was also the area of highest leiognathid density. Habitat 2 -- (Plate 1B) This habitat was dominated by stands of the seagraSS Enhalus acoroides, sometimes with admixtures of other sea- grasses and algae. The substrate was fine sand. Depths rang-ed from 1.0-1.5 m. This habitat only occurred in inshore areas. Rabbitfish were the most abundant food fishes in this habitat, and goatfish and snappers were relatively abundant. HabitaL 3 -- (Plate 1C) This habitat was characterized by heavy stands of the seagrass Halodule uninervis which provided virtually complete coverage of the sand substrate. This was a relatively shallow (1.0-3.0 m) habitat, occurring predominantly inshore. The largest counts of snappers occurred in'this hab-itat although most of these snappers were small juveniles. The greatest abundance of rabbitfish wa's also found in this habitat, and goatfish, primarily Parupeneus barberinus, were relatively abundant. Sparids, whLch were seldom seen anywhere, reached their highest densities in thishabitat. Habitat 4 -- This habitat was also dominated by Halodule, but in patches rather than continuous stands. Dead coral and algae including a diverse assemblage of Caulp_exa, also occurred here. The highest counts of silversides occurred in this habitat but even these were in rather low abundance. No other economically important fishes were particularly abundant in this habitat. , Habitat 5 -- The only occurrence of this habitat was at the north end of the lagoon. It was shallow (0.5-1.5*m) and characterized by a sandy substrate with a variety of algae, including Boergesenia forbesii and the red alga Gracilaria edulis, and scattered small corals. No 5 economically important fishes were abundant here, although it was one of only two habitats where silversides were seen and one of only three habitats where leiognathids were seen. Habitat 6 -- (Plate ID) This sandy habitat contained scattered patches of Sargassum polycystum, and a large number of small black sea cucumbers. Depths were 0.8-2.0 m, Goatfish (mainly Parupeneus barberinus and Mulloidichthys flavolineatus) were the most abundant food fish in this habitat and cardinalfish were found in their second-highest density here. A few medium-sized high-bodied jacks were also seen. Habitat 7 -- This habitat was found mid-lagoon at a depth of 1.5- 3.0 m. The substrate was composed of sand and rubble supporting growths of Padina, Cauler2a, Dictyota and other algae. A moderate diversity of fis s was found here but no economically important fishes were seen in particularly high abundance. A small species of barracuda was seen only in this habitat. Habitat 8 -- (Plate 1E, F) This habitat consisted of mid-lagoon patch reef areas characterized by living and dead corals and reef- building coralline algae. Depths were 0.5 to 2.0 m. Fish diversity was rather high in this habitat. Juvenile parrotfish were at their highest density in this habitat, and rabbitfish were fairly common. Habitat 9 -- (Plate 1C) This habitat was found in inshore dredged areas from Charlie Dock to Puntan Muchot. The substrate was silt with rubble, wreckage, and some coral growth. The water was rather turbid. Despite the poor visibility, the greatest density of high-bodied jacks was seen in this habitat. These were rather small subadult fishes swimming in schools. Habitat 10 -- (Plate 1H, 2A, B) This was the main harbor area and extended to depths of 12 m. Extensive stretches of sand dominated this habitat, but isolated outcrops of coral were not uncommon. There was a moderate diversity of fishes seen in this habitat. The highest density of edible-sized snappers (principally Lutjanus kasmira) occurred in this habitat (the higher count of snappers from habitat 3 reflects the abundance of juvenile snappers there). Adult parrotfish and surgeonfish were also fairly common in this habitat. Among the poten- tial baitfish, cardinalfish were at their greatest density and blue Chromis at their second greatest density in this area. Habitat 11 -- This habitat consisted of extensive stretches of sand with occasional small patches of H-alodule. Depths ranged down to 2.5 m. Few fishes of any kind were seen in this habitat. It was the only area where milkfish were s"een, although these were in very low abundance. A large stingray, Taeniura melanospilus, was seen here. Habitat 12 -- (Plate 2C, D) This area was characterized by uninterrupted stretches of sand covered with the blue-green alga 6 Microcoleus lyngbyaceus. It was approximately 3 m deep. Few fishes occurred her e, but the density of slender-bodied jacks was greatest in this habitat. Habitat 13 -- (Plate 2E, F) This sandy-bottomed habitat supported a rather extensive cover of the small seagrass Halophila minor as well as other algae and numerous sea cucumbers. The depth was approximately 1.2-2.5 m. Fish diversity was rather low. No economically important fishes were abundant in this habitat, although there was a moderate density of cardinalfish in small holes. Habitat 14 -- (Plate 2G, H) This mid-lagoon habitat was character- ized by a sandy substrate with fairly numerous clusters of Acropora scattered throughout. The depth was approximately 1.5 m. Species diversity was rather high here. Goatfish, primarily Mulloidichthys flavolineatus, were at their highest density in this habitat, and juvenile parrotfish were at their second-highest density. Blue Chromis were moderately abundant. Habitat 15 -- (Plate 3A, B) This was an area of well-developed Acropora formosa colonies near a reef channel. Depths ranged from 0.5 to 3-5 m. Many species of fish were seen in'this habitat. Large squirrelfish, primarily Flammeo spp., were at their greatest density. Several other economically important fishes were seen in moderate to high densities in this habitat, including goatfish (Mulloidichthys flavolineatias), snappers (Lutjanus kasmira), juvenile parrotfish, and blue Chromis Habitat 16 This consisted of the lagoon fringing reef south and east of Managaha Island. It was an area of fairly rich coral growth and some algae. Depths ranged from 0.5 to 4.5 m. Species diversity was high. Edible-sized groupers, which were nowhere very abundant, were at their highest density here. Large wrasses, surgeonfish, and adult parrotfish were also fairly abundant in this area. Habitat 17 -- (Plate 3C,-D) This was an area of numerous patch reef west of Managaha Island. Coral growth was luxurient on these Patch reefs. Depths ranged from 0.5 to 5.0 m. Species diversity was rather high. Surgeonfishes and large wrasses were fairly abundant in this habitat. Habitat 18 -- (Plate 3E, F) This habitat occurred near the barrier reef in the.northern part of the lagoon. It was characterized by sand, rubble, scattered Acropora, Padina, and other algae. Depths were 1.0-4.0 m. A moderate diversity of fish occurred in these areas. No economically important fishes were abundant in this habitat. Habitat 19 -- Thq lagoonward fringe of the barrier reef at the southern part of'the lagoon comprises this habitat. Depths were 0.2- 2.0 m. The substrate was predominantly coralline algae, with sand and 7 some coral growth. Fish diversity was rather high in this habitat. Juvenile parrotfish, rabbitfish, and surgeonfish were moderately abundant. Habitat 20 -- (Plate 3G, 4A) This was a band of rich coral growth near the northern lagoon barrier reef. Depths were 0.5-1.5 m. Species diversity was rather high in this habitat. Goatfish, juvenile parrot- fish, and surgeonfish were relatively abundant in this habitat. This was one of the few places where sharks were seen in the lagoon. Habitat 21 -- (Plate 4B) This habitat occurred at the lagoonward fringe of the barrier reef at the northern and western margins of the lagoon. Depths ranged from 0.5 to 2.0 m. Coral growth was rich in these areas, and fish species diversity was rather high. Blue Chromis were at their highest densities in this habitat. Large wrasses, rabbitfish, and juvenile parrotfish were moderately abundant. Habitat 22 -- (Plate 4C, D) This habitat was a highly dissected, submerged barrier reef with coral, sand and algae. Growth of the alga Chlorodesmis was lush. Depths ranged from 0.5 to 5.0 m. Fish species diversity was relatively high. Surgeonfish (primarily Acanthurus lineatus) were quite abundant in this habitat. Juvenile and adult parrotfish occurred in moderate abundance. Habitat 23 -- (Plate 4E, F) This was a zone of spur and groove topography seaward of the barrier reef. Depths ranged from 1.0-4.0 m. The habitat was subject to heavy surge. Greatest fish diversity was recorded in this habitat. It was among the two habitats of highest surgeonfish abundance (primarily Acanthurus lineatus) and was the area highest in abundance for adult p otfish, large wrasses, and large groupers. Some very large needlefish were also seen in this zone. Habitat 24 -- (Plate 4G, H) This was a deeper (6.0-10.0 m) zone seaward of the western barrier reef. It was an area of coralline algae mounds with deep holes and sand channels. A relatively high diversity of fishes occurred in this habitat. The highest density of surgeonfish was seen here, as well as a reasonably large number of adult parrotfish. This was the only habitat where rudderfish and fusiliers were censused. 8 DISTRIBUTION AND ABUNDANCE OF FISHES OF POTENTIAL ECONOMIC IMPORTANCE The twenty-two categories of economically valuable fishes censused in Saipan Lagoon are characterized in the following listing. A summary of their.gene.ral distribution and an evaluation of their economic poten- tial are given for each category. More detailed data on the distribu- tion of each fish category are given in Table 1. Sharks (Carcharhinidae and Orectolobidae) -- The estimate of 277 sharks in Saipan Lagoon is based on a rather small number of actually observed sharks and is probably not a very accurate figure. Two species were seen, the blacktip shark Carcharhinus melanopterus and the nurse shark Nebrius ferrugineum. Considering the densities observed, there is little economic potential in shark fishing in lagoon waters. Milkfish (Chanidae; Agua) --Again, the estimated abunda-Ace of these fish is based on few actual observations and is not likely to be an accurate assessment. Milkfish do not appear to have any economic poten- tial in Saipan Lagoon. La rge Squirrelfish (Holocentridae; Sesiok, Chalak) -- (Plate 5A) These were quite numerous in habitat 15 where the large masses of Acropora provide these fishes with cover during the daytime. The most abundant of these squirrelfish were ones belonging to the genus Flammeo and these are not as highly regarded as some of the large species of Adioryx (e.g. A. spin.ifer). As our censusing was carried out during the daytime and squirrelfish are predominantly nocturnal, we have quite likely under- estimated their true abundance. Mullets (Mugilidae; Laiguan) -- (Plate 5B) Adults were seen in the small mangrove-lined embayment east of Charlie Dock (Habitat 1). They were not especially numerous. Other adult mullet were seen in habitats. 3 and 2:3, but not during the census counts. Some juveniles of baitfish size Were collected in the small boat harbor east of Puntan Muchot, but these were not abundant enough to be a valuable baitfish resource. There seems to be no economic potential for mullets in the lagoon. Barracuda (Spyraenidae; Alu) -- (Plate 5C) The only sighting within the lagoon was of a single school of approximately 200 individuals of a relatively small species tentatively identified as Sphyraena chinensia. Some large barracuda were'seen off the northeast coast of Saipan near the seaward opening of the Grotto. Large Groupers (Serranidae; Gadao) -- (Plate 5E) This category included all groupers large enought to eat. These fishes are sometimes hard to see as they are often rather cryptically colored and wait motionless on the bottom or in holes to ambush their prey. We may have underestimated their true abundance, but it appears that fishing for large groupers in the lagoon would offer little yield. Epinephelus merra was the dominant lagoon species. 9 Slender-bodied Jacks (Carangidae; (Plate 6A) In this category are carangid fishes of the genera Scomberoides, Decapterus, Trachurops, and others with this general body shape. Although the atulai, Trachurops crUmenopthalmus, is seasonally very abundant, none were seen during our surveys. Very few jacks of this type.were seen in the lagoon. High-bodied JaLks (Carangidae; Ee, Tarakito) -- (Plate 5H) This catego 'ry includes carangids of the genera Caranx, Carangoides, and others. Small Caranx melampygus were quite abundant in the inshore areas of habitat 9, but large ones were only seen ih zones near the barrier reef in areas of heavy surge. Snappers (Lutjani.dae and Lethrinidae, in part; Funai, Kakaka, Tagafi, Mafute) -- (Plate 6B, C, D, F) Included in this category are species in the genera Lutjanus and Lethrinus. The highest abundance of these fishes was recorded in the Halodule stands of,habitat 3,-but most of those counted were juvenile Lethrinus. In th@ harbor area of habitat 10, Lutjanus kasmira dominated an abundant snapper assemblage. Some very large Lutjanus bobar were seen in habitat 24. The population of snappers in Saipan Lagoon is large, estimated at some 120,000 individuals, and represent's a significant food resour,ce. Snappers in inshore areas could best be harvested with nets, while those of the deeper and more offshore areas would be more effectively taken with spears and handlines. Leiognathids (Guaguas) -- (Plate 6H) These silvery fishes are related to snappers. They are characteristically found in brackish and inshore areas, which is also the case in Saipan Lagoon. They were nowhere numerous enough nor dense enough to be an important fishery resource. Sparids (Salagai, Matanhagon, Sihig) -- (P late 66) This category contains a variety of snapper-like fishes in the gene ra Monotaxis, Scolopsis, and Gnathodentex. Although locally abundant in various areas in Micronesia, no important concentrations of them were seen in Saipan Lagoon. Rudderfish (Kyphosidae; Guili) -- (Plate 5G) No'rudderfish were seen inside Saipan Lagoon. The only ones seen on this survey were on the outer reef terrace, and even here they were in low abundance. Several large rudderfish were seen outside the Grotto on the northeast coast of Saipan. Goatfish (Mullidae; Salmoneie) -- (Plate 7A) Goa@fishes are one of the major fish resources of Saipan Lagoon. The high density of goat- fish in the mid-lagoon habitat 14 reflects the great numbers of the schooling Mulloidichthys flavolineatus in the area. Parupereus barberinus was also present, but in lesser abundance,Jn this habitat. 10 Rather.large schools of M. flavolineatus were also seen at the Acropora dominated habitat 15. T@h_e'coral-rich habitat 20 also supported a sub- stantial number of goatfish of the species P. trifasciatus, P. barberinus, and M. flavolineatus. Other habitats with high densities of goatfish are 3, 6, and 18. Goatfish are most effectively taken by nets of various sorts. Large Wrasses (Labridae; Aaga, Tanguisson) -- (Plate 7D, E) This category contains primarily large individuals of the genera Cheilinus, Coris, Epibulus, Hemigymnus, and Thalassoma. They were most abundant in areas of -rich reef development in habitats 8, 16, 17, 21, 23, and 24. In these habitats they are most effectively taken with spears. Outside the reef these fishes can also be captured by handlining and traps. Standing stocks are great enough for these fishes to comprise a valuable resource. Parrotfish (Scaridae; Palagsi) -- (Plate 7G) Although some juvenile parrotfish may be harvested for food, most people prefer to take the larger adult individuals. However, in order to assure the continued production of larger parrotfish, the habitats of the juveniles must be maintained. Juvenile parrotfish are most numerous in relatively coral- rich habitats inside the lagoon, in particular habitats 8, 14, 15, 19, and 21. Adult parrotfish prefer more exposed locations'on. or outside the barrier reef such as habitats 22, 23, and 24. They are also moderately abundant in the deep harbor area of habitat 10. Parrotfish are one of the most important reef fish resources of Saipan Lagoon. SurgeOLfisbes (Acant huridae; Hijuc, Hugopau, Kicho, Hangon, Tataga) (Plate 7F) Our counts of surgeonfishes included some forms which are not generally harvested for food such as juveniles and members of the genus Zebrasoma. However, the great majority of surgeonfish censused were edible-sized Acanthurus, Ctenochaetus, and Naso. The greatest concentra- tions of surgeonfishes were in barrier reef habitats 23 and 24. Acanthurus lineatus dominated the surgeonfish counts in these habitats. Coral-rich habitats 16, 17, and 22 also had high surgeonfish densities. A. lineatus dominated in habitat 22, while in habitats 16 and 17 other species such as A. triostegus, A. glaucopareius, Ctenochaetus striatus, and Naso literatus were also common. Lesser, but significant, concen- trations of surgeonfish were seen in habitats 9, 10, 15, 19, 20, and 21. Surgeonfish are the most abundant food fish resource in Saipan Lagoon. Rabbitfish (Siganidae; Sesjun -- (Plate 7H) Large numbers of rabbit.fish were seen during the surveys, and all were of edible size. or close to it. No juveniles (manahac, dage) were seen. Rabbitfish were most abundant in the seagrass dominated habitats 2 and 3. They were also moderately abundant in habitats 8 and 19. Rabbitfish can Most effectively be taken with nets in the seagrass areas and with spears; in the more coralliferous habitats. They are a major food fish resource in Saipan Lagoon. 11 Other Food Fish -- Although not enumerated during the censuses, some other potential food fish were seen in very low abundances in or near the study area. Flagtails (Family Kuhliidae; Atingyet; Plate 5F) were seen in a tide pool at Puntan Aginjan and at the Grotto. Several very large needlefish (Family Belonidae; Pulus) were seen off the barrier reef in habitat 23. Occasional Flatfish (Family Bothidae; Tampat) were seen in habitats 4, 6, and 13. None of these fishes were abundant enough to be considered as valuable food fish resources. The'fish groups considered below are evaluated in terms of their potential as skipjack tuna baitfish. They have all been used at one time or another as baitfish in the Western Pacific (Wilson, 1971; Baldwin and Hida, unpublished). Silversides (Atherimidae; Ginyo) -- Small schools of these silvery fishes were seen in habitats 4 and 5. Concentrations are insufficient for use As baitfish. Cardinalfish (Apogonidae; Lansi) -- (Plate 5D) Not all cardinal- fish make good baitfish and some of the cardinalfish we censused fall into this category. Greatest concentrations were found in habitats 6., 7 and 10 clustered around coral outcrops or cables and other man- made objects in the water. The rather low densities and the difficulties involved in collecting enough of these fishes to use in baiting suggests that these fishes are not likely to be a useful baitfish resource. However, these fishes are primarily nocturnal and secretive during the day and we have quite likely underestimated their abundance. Fusiliers (Caesionidae; Bonita) -- (Plate 6E) These fishes are schooling, plankton-feeding fishes related to the snappers. They were only seen outside the barrier reef in habitat 24. These fishes are quite abundant in Truk Lagoon and have been used as tuna bait in that area, but they are not abundant enough in the Saipan Lagoon area to be used as a baitfish. Blue Chromis (Pomacentridae. in part) -- (Plate 7B, C) Two species, Chromis caerulea and C. atripectoralis, are included in this category. These fishes are extremely abundant in Saipan Lagoon (wit-h an estimated total abundance in excess of 4 million). Greatest densities were in habitats 10, 15, and 21, with reasonably high densities in habitats 7, 8, 9, 14, 18, and 20. C. caerulea typically occurs in large aggregations around coral heads, while C. atripectoralis tends to occur further out in the water column, less closely associated with the coral substrate. While Chromis is not considered an ideal tuna baitfish, it is adequate in the absence of any better choices. Its great abundance in the lagoon indicates that there is a baitfish potential in these fishes. The major difficulty is in collecting enough of them without damaging the corals in which they live. None of the more highly regarded clupeoid-type baitfishes (Families Clupeidae, Dussumieridae, and Engraulidae) were seen in Saipan Lagoon. 12 EQUILIBRIUM YIELDS OF EXPLOITABLE FISH POPULATIONS For a fish population to remain in equilibrium, that is,'for popu- lation size to remain more or less constant.over a long period of time, the number of fish-removed from the population-through harvesting pr natural death must not exceed the rate at which young fishes of the -same kind (-recruits) can replace the loss. 'It is also necessary,lof course, that: the amount of appropriate habitat available to the fish population remain constant. A given fish population can exist-at a, variety Of equilibrium abundance levels. The particular equilibrium population size and the particular equilibrium yield which can be har- vested will depend, to a great extent, on the rate at which the harvest- ing takes place. With no harvesting, the population can achieve its greatest equilibrium abundance while the equilibrium yield will be zero. At very high levels of fishing, the population will become smaller and smaller, eventually becoming fished-out so that the yield is so low that it is no longer worthwhile to fish for that type of fish. 'Under these conditions, the equilibrium population size is very low (or zero) and the equilibrium yield is also very low (or zero). Between the-two extremes of no fishing and very heavy fishing exists a level of harvesting which produces the maximum equilibrium (or maximum sustainable) yield. The equilibrium population size-at this level of fishing is generally somewhere around half of the maximum population size when there is no fishing at all. Sale (1977) has argued that tbe,population-size of many reef fishes depends; primarily on the amount of living space available. Fishes pro- duce large numbers of eggs and larvae. When these larvae develop,and reach the stage at which they are ready to recruit to the adult popula- tion, they can only recruit if they encounter appropriate living space. Those that don't find living space die and do not become part of the adult population. If this is indeed the case, then reef fish.popula- tions should remain fairly constant under a rather large range of har- vesting pressures as long as sufficient numbers of reproductive adults remain in the population to produce-enough offspring to recruit to all available appropriate living space. "Turnover time" can be defined as the average time it takes for a newly spawned, fish egg to grow to maturity and become a reproductive adult fish. Turnover time is basically the same as generation time, but will be used in the following discussion to mean the time duration from newly spawned egg to median harvestable size. Turnover time can be visualized as the time it would take a batch of newly spawned eggs to replace its parent population if that parent population we7re completely harvested (assuming that the parent population wasn't harvested before it reached reproductive maturity). As an example, if a particular species of fish took one year to develop from egg to median adult size, it would be possible to harvest all the adults in 13 one year's time and they would be replaced by their offspring. If the turnover time of a particular population was two years, the whole adult population could be harvested every two years (or half of it could be harvested every year) and the population would still be able to replace itself; in other words, the population would remain in equilibrium. This rather simplistic model of fish population dynamics, which ignores natural mortality, interspecific competition, variations in growth rates, and variations in egg and larval survival, is used here to provide pre- liminary estimates of maximum rates of harvesting which will leave the populations in equilibrium. A major difficulty in this approach is obtaining accurate values of turnover time for the various groups of economically important fishes. Most of the categories which were censused are made up of several species which may have different turnover times. Few studies on rates of growth and maturation of reef fishes of any kind have been done, and few of any of the available studies have been done in the western Pacific. In Table 2 we have presented estimates of equilibrium annual harvesting rates for some economic fish categories. We were unable to obtain age and growth information for many of the categories, however, and harvest estimates are not given for these. Even for those categories for which annual equilibrium harvest estimates are given, it is important to stress that the turnover time estimates are very tentative and often based on species which are not important (or do not occur) in Saipan Lagoon. These annual harvest estimates should not be used as a basis for fishery management until validated by further studies. FISH SPECIES DIVERSITY Two hundred forty nine species of fish were seen in the twenty four surveyed lagoon habitats (Table 3). An additional three species, Adioryx lacteoguttatus (Cuvier and Valenciennes), Apogonichthys ocellatus (Weber), and Plesiops caeruleolineatus Ruppell., were seen in a man-altered rubble area near habitat 3. Habitats richest in fish species were those asso- ciated with the barrier reef, coral rich habitats near Managaha Island, and the rich growth of Acropora. of habitat 15 (Map 24). Few species were seen in the mangrove-lined embayment of habitat 1 or the blue green algae covered sand of habitat 12. A fish resource with potential economic importance is salt-water aquarium fish. Although the present study did not address itself par- ticularly to this resource, the map of species richness (Map 24) is a good guide to areas where the diversity of possible aquarium fish is highest, and Table 3 gives the specific habitat locations of many fish species which could be harvested for the aquarium trade. 14 DISTRIBUTION OF FISH LARVAE AND EGGS The maintenance of reproductively viable population levels is essen- tial to the management of any potential fisheries resource. The produc- tion of offspring by fishes is usually by the release of sperm and eggs into the water column where the fertilized egg float.s freely as a tem- porary "member" of the zooplankton community. There are certain fishes whose eggs are not planktonic. Of the twenty-two listed groups of fishes counted in this survey, those with non-planktonic eggs include the blue Chromis with demersal attached eggs (Sale, 1977), the apogonids, many of which are mouth brooders (Breder and Rosen, 1966)and the sharks which are live-bearers. Upon hatching, however, most demersal eggs release pelagic larval stages. The eventual destination of these eggs and larvae is largely dependent upon the circulation pattens of the par- ticular area and upon the time required for larval development. This lag time in fishes may be as little as 12 hours or as long as several weeks. The site of larval rearing and egg development is often quite separate from the area of concentration of the exploitable resource. Identification and protection of these areas is an integral part of population maintenance and a necessary step in the planning of resource management. The zooplankton community of Saipan Lagoon as a,whole was found to be rather sparse, averaging only 66.2 (n--'17, s=151.7) individuals per cubic meter. This is considerably lower than densities found in a 3 similar survey of the zooplankton community of Yap Lagoon of 257.7 per M (Lassuy, 1978) and far lower than was found near Ebeye in Kwajalein Atoll of 617/m3 (Amesbury et al., 1975). Densities similar to those found in Saipan Lagoon have been recorded from Arakabesan (Randall et al., 1978) and Malakal Islands (Birkeland et al. 1976) in Palau. Densities for individual tows ranged from 1.7 per m@ for tow no. 14 near the reef mar- gin At the proposed site of the fishery complex to a high of 631.6 per M3 for two no. 12' in the-vicinity of the mangrove channel just north o 'f Charlie Dock. The densities of individual taxa of zooplankters are detailed in Table 4. The distribution of fish eggs and larvae appears to be widespread in Saipan Lagoon as eggs were observed in all 17 and larvae in 14 of the 17 tows. The only other taxon recorded in all tows was the ubiquitous copepods. Other consistent contributors to the zooplankton community included brachyuran crab zoeae and foraminifera which both occurred in 15 of the 17 tows and shrimp larvae which were counted in all but three of the tows. Together these six taxa form the bulk of all tows averaging 92% (n=17, s=(').5) of the total density and ranging to as high as 98.8%. Occasionally numerous in the counts were the chaetognaths and larvaeceans which were observed in 10 and eight tows, respectively. Both of these reached their highest proportions in the inner harbor areas of tows no. 11 and 1.2. Doty and Marsh (1977) report particularly slow and sometimes eddying water movements in this area which seems to represent an area of generally enriched plankton abundance. 15 As an individual taxon, the fish eggs were by far the most consis- tently important contributors to zooplankton abundance averaging 54.0% (n=17, s=28.3) and ranging to as high as 96.2% of the total density. 3 The density of fish eggs was generally from about one to 25 eggs per m with a mean of 14.3 per m3 (n=17, s=19.5). There were two tows with sharply higher values than the remaining 15 tows. These were tows no. 1 and 4 which had egg densities of 54.8 per m3 and 66.4 per m3, respect- ively. Both tows were made in proximity to areas of habitat-type no. 3, rich Balodule seagrass beds. Tow no. 1 was directly over a thick Halodule bed to the north of the harbor area. The density of larval fish appears quite low (Table 4). However, the maximum density of 3.1 larvae per m3 in the area of habitat no. 1, the mangrove channel, is similar to some of the higher densities found in the Yap Lagoon survey (Lassuy, 1978). Their consistently high representation in the zooplankton communities of the mangrove canals of Yap suggested these areas to represent significant nursery grounds for the rearing of larval fish. In general, then, while the abundance of zooplankton in Saipan Lagoon as a whole seemed relatively low, the contribution of fish eggs and larvae was particularly pronounced. Habitat 3, richly developed seagrass beds primarily composed of Halodule uninervis, seemed to be exceptionally productive areas in terms of tb production of fish eggs. While no water movement studies were carried out during this survey, it was apparent that flow was quite rapid and generally in the direction of the harbor. The report of irregular and slow water movements in the area of the inner harbor suggest this may represent an area of conver- gence for water masses from the north and south extensions of the lagoon. The additional factor of freshwater being introduced into the system, as was mentioned for habitat no. 1, makes the inner harbor area an es- pecially likely location for the accumulation of nutrients and the possi- ble development of an enriched plankton community. After exhausting the food reserves of its egg sac, it would obviously be advantageous for a larval fish to be in an area of enriched food supply to support its rapid development and growth. Should the suggested water movement pattern be indeed the case, the tows seemed to reveal a possible strategy for the successful production of offspring by the fishes of Saipan Lagoon. With egg production occurring in the north and south extensions of the lagoon and with allowance for the mentioned lag time in larval development during transit to the harbor area, the hatched larvae would then be in the richest area of food production within the lagoon, i.e., the mangrove channel and inner harbor areas. The results of the zooplankton analysis thus suggest that the pro- tection and management of the rich Halodule beds of habitat no. 3, the mangrove channel of habitat no. 1 and adjacent areas are integral to the maintenance and development of a viable fishery in Saipan Lagoon. 16 CONCLUSIONS AND RECOMMENDATIONS PLANNING AND HABITAT PROTECTION Because reef environments surrounding Micronesian islands are almost always beautiful and rich in marine life@, it is difficult for planners to locate shoreline developments in areas where environmental impacts will not be felt. At the same time, most'Micronesian reef systems are relatively limited in extent, and even small-scale impacts may have important consequences. Among the many considerations that go into selecting a site for future development, an important one is the possible effect of environmental modification on the habitats of economically important fishes. In making these recommendations, we are guided by the fpllowing principles: 1) Because relatively little is known about the specific habitat requirements of the great majority of reef fishes throughout their entire life cycle, and many fishes may reside in different habitats during their early life than they do as adults, it is important that a significant amount of each distinct kind of lagoon habitat be maintained in a relatively unmodified condition. 2) Habitats where economically important fishes are abundant should be preserved to the greatest extent possible so that the maximum economic benefit can be derived from the harvesting of these fishes. 3) Habitats in which spawning or nursery grounds for fish are suspected, because of the occurrence of high densities of fish eggs and larvae in the water, should be protected. 4) Habitats in which fish species diversity is high should be protected. Needless to say, there are many other grounds for protecting various lagoon areas, such as the presence of economically important organisms other than fish, areas of easy access for tourists and sport divers, habitats of endangered species, etc. Recommendations Habitats 1 and 15 should be protected in their entirety because of their uniqueness and limited extent. Habitat 1 also contained the highest density of mullets and leiognathids. Habitat 15 had the 17 highest density of large squirrelfish, rather high densities of several other economically important fish groups, and a high diversity of fish species. Because of high densities of economically valuable fish species, as large,an extent as possible of the following habitats should be preserved intacts: Habitats Important resources fishes 2 rabbitfish 3 snappers, rabbitfish, goatfish 4 juvenile parrotfish 6 goatfish 7 juvenile parrotfish, barracuda 8 large wrasses, juvenile parrotfish, rabbitfish 9 high-bodied jacks, surgeonfish 10 snappers, adult parrotfish, surgeonfish, blue Chromis 12 slender jacks 14 goatfish, juvenile parrotfish, blue Chromis 15 squirrelfish, goatfish, juvenile parrotfish, surgeonfish, blue Chromis 16 large groupers, large wrasses, adult parrotfish, surgeon- fish 17 large wrasses, surgeonfish 18 goatfish, juvenile parrotfish, blue Chromis 19 juvenile parrotfish, surgeonfish, rabbitfish 20 goatfish, juvenile parrotfish, surgeonfish 21 large wrasses, juvenile parrotfish, surgeonfish, rabbitfish, blue Chromis 22 juvenile and adult parrotfish, surgeonfish 23 large groupers, large wrasses, adult parrotfish, surgeonfish 24 large wrasses, adult parrotfish, surgeonfish The egg and larvae surveys indicated that habitats 1 and 3 are important areas for the early developmental stages of many fish. How- ever, because we were not able to identify the fish eggs and larvae, it is quite possible that many fish species have their spawning and nursery ground in other parts of the lagoon. Many fish may be spawn- ing and undergoing larval development during other times of the year. Habitats in which fish species diversity was particularly high are habitats 8, 14, 15, 16, 17, 19, 20, 21, 22, 23, and 24. Major portions of these habitats should be protected. The above recommendations are made on the basis of the surveys performed in January 1979. At other times of the year, fish populations in Saipan Lagoon may be more or less abundant than they were during this study and may be distributed somewhat differently. Further information on the dynamics of the fish populations in Saipan Lagoon 18 could require modification of these recommendations. ESTIMATES OF EQUILIBRIUM YIELDS The equilibrium yield estimates given in Table 2 have been calculated according to the following formula: Yi Z (Aj x Ni,j/C)/Ti i where Yi annual equilibrium harvest of fish category i Aj area of habitat i (m2) Ri,j = average number of members of fish category i seen in habitat j in 10 minutes C' area covered by census in 10 minutes (m2) Ti estimated turnover time of fishes in category i (years) The accuracy of the equilibrium yield estimates depends upon the accuracy of each of the parameters used to calculate it. More accuracy could be achieved by the following means: 1) additional censusing within each habitat type to obtain better estimates of the mean abundance of each fish category within each habitat; 2) subdivision of the habitats into a larger number of smaller habitats to take into account the variation of fish distribu- tion within habitats; 3), more precise measurements of the area covered by each habitat; 4) more precise determination of the area covered during the 10-minute censuses; 5) censusing during other times of the year to take into account seasonal variations in fish abundance in different habitats; 6) bet-ter estimates of turnover time of fish categories based on the particular species which dominate in Saipan Lagoon; 7) a finer breakdown of fish categories to take into account variations in turnover time among different species which have been lumped into a single category. Fundamen@tal to the value of estimating equilibrium yields is the need for accurate catch data for fishes taken from the lagoon. Unless 19 there is a way to know how many fishes of the various categories are being harvested annually, it is not possible to determine whether particular categories are overbarvested or underharvested and so there is no effective means for managing the stocks. 20 LITERATURE CITED Amesbury, S. S., R. T. Tsuda, W. J. Zolan, and T. L. Tansy. 1975. Limited current and underwater biological surveys of proposed sewer outfall sites in the Marshall Island District: Ebeye, Kwajalein Atoll. Univ. Guam Mar. Lab., Tech. Rept. 23, 30 p. Baldwin, W. J., and T. S. Hida. unpublished. A summary of the Pacific Ocean skipjack tuna fisheries an'd a description, evaluation, and distribution of the principal baitfishes. Paper presented at the Tuna Baitfish Workshop, Honolulu, June 4-6, 1974. 159 p. Breder, C. M., and D. E. Rosen. 1966. Modes of reproduction in fishes. TFH Publ., Jersey City, N. J. 941 p. Cloud, P. E., Jr. 1959. Geology of Saipan, Mariana Islands. Part 4. Submarine topography and shoal-water ecology. Geol. Surv. Prof. Pap.,280-K, pp 361-445. DeSylva, D,. P. 1963. Systematics and life history of the great barracuda Sphyraena barracuda (Walbaum). Stud. Trop. Oceanog. 1:1-179. Doty, J. E., and J. A. Marsh, Jr. 1977. Marine survey of Tanapag Harbor, Saipan: The power barge "Impedance." Univ. Guam Mar. Lab., Tech. Rept. 33, 147 p. Hasse, J. J., B. B. Madraisau, and J. P. McVey. 1977. Some aspects of the life history of Siganus caniculatus (Park) (Pisces: Siganidae) in Palau. Micronesica 13:297-312. Johannes, R. E. in press. Using knowledge of the reproductive behavior of reef and lagoon fishes to improve fishing yields. In: J. Bardach, J. Magnuson, R. May, and J. Reinhart (eds.) i7sh behavior and fisheries management (capture and culture). ICLARM, Manila. 25 p. Lassuy, b. R. 1978. Quantitative assessment of the zooplankton assemblages in Yap Lagoon. In R. I. Tsuda (ed.) Marine biological survey of Yap Lagoon. Univ. Guam Mar. Lab., Tech. Rept. 45, pp. 132-140. Randall, J. E. 1961. A contribution to the biology of the convict surgeonfish of the Hawaiian Islands, Acanthurus triostegus sandvicensis. Pac. Sci. 15:215-272. 21 Randall, J. E. 1973. Tahitian fish names and a preliminary check- list of the fishes of the Society Islands. Occ. Pap. B. P. Bishop Museum 24:167-214. . 1977. Contributions to the biology of the whitetip reef shark. Pac. Sci. 31:143-164. and A. Mauge. 1978. Visit to Djibouti. The Marine Aquarist. 8:39-52. Randall, R. H., C. Birkeland, S. S. Amesbury, D. Lassuy, and J. R. Eads. 1978. Marine survey of a proposed resort site at Arakabesan Island, Palau. Univ. Guam Mar. Lab., Tech. Rept. 44, 73 p. Roede, M. J. 1972. Color as related to size, sex, and behavior in seven Caribbean labrid fish species (genera Thalassoma, Halichoeres, and Hemipteronotus). Martinus Nijhoff, The gague. 266p. Sale, P. F. 1977. Maintenance of high diversity in coral reef fish communities. Amer. Nat. 111:337-359. Schultz, L. P., E. S. Herald, E. A. Lachner, A. D. Welander, and L. P. Woods. 1953. Fishes of the Marshall and Marianas Islands, Vol. 1. U. S. Nat. Mus. Bull 202:1-685. Swerdloff,.S. N. 1970. The comparison of two Hawaiian species of the damselfish genus Chromis (Pomacentridae). Ph.D. Diss., Univ. of Hawaii. 192 p. Thompson, R., and J. L. Munro. 1916. Aspects of the biology and ecology of Caribbean reef fishes: Serranidae (hinds and groupers). J. Fish. Biol. 9:115-146. Tsuda, R. T., W. J. Tobias, P. G. Bryan, W. J. FitzGerald, Jr., H. T. Kami, and I. I. Ikehara. 1976. Studies on the genus Siganus (Rabbitfish) in Guam waters. Univ. Guam Mar. Lab., Tech. Rept. 29, 93 p. Watari, L. T. 1973. Growth rate of a carangid fish, the omaka Caranx mate, in Hawaii. Trans. Amer. Fish. Soc. 102:617-620. Wilson, P. J. 1971. Truk live-bait survey. NOAA Tech. Rept. NMFS CIRC-353, 10 p. 22 Table 1. Density (no./1000 m2 ) and estimated total abundance of economically important fish groups in various habitats of Saipan Lagoon. 0 Total Sharks Milkfish Area Total Total Habitat (M ) Density Abundance Density Abundance 1 8,813 2 2,21.5,101 3 1,844,938 4 1,166,307 - - 5 290,842 - - 6 778,517 - - 7 1,222,125 - - 8 1,01-0,603 - - 9 240,900 - - 10 6,045,992 - - 11 3,246,269 - - .08.5 1129 12 749,139 - - - - 13 831,397 - - - - 14 1,695,111 - - - - 15 91,072 - - - - 16 496,488 17 951,847 18 2,273,857 19 5.31,742 20 1,633,417 .085 139 21 2,743,905 - - 22 637,503 23 2,834,977 - - 24 1,624,603 .085 138 - Total 35,165,466 277 129 only part of habitat 11 consi- dered appro- priate for milkfish 23 Table 1.(continued) Large Large Squirrelfish Mullets Barracuda Groupers Density Total Density Total Density Total Density Total Habitat Abundance Ab-undance Abundance Abundance 1 8.165 7.2 2 3 - - .085 157 4 .750 875 - - 5 6 7 16.665 20,367 - - 8 - - .085 86 9 10 .915 5,912 .085 514 11 12 13 14 - - - - - - - - 15 14.250 1,298 - - - - .085 8 16 .085 42 - - - - .250 124 17 .165 157 - - - - .085 81 18 - - - - - - - - 19 20 - - 21 .085 233 - - 22 - - .085 54 23 '.085 241 .250 709 24 .335 544 - - .085 138 Total 8,922 72 20,367 1,871 24 Table 1. (continued) Slender High-Bodied Jacks Jacks Snappers Leiognathids Density Total Density Total Density Total Density Total Habitat Abundance Abundance Abundance Abundance 1 .085 1 .750 7 2 3.250 7,199 .415 919 3 18.500 34,131 - - 4 5 - - .250 73 6 195 .415 323 - - 7 8 .085 86 2.250 2,274 9 12.415 2,991 2.085 502 - 10 - - 10.415 62,969 - 11 .085 276 - .085 276 - 12 .585 438 - .335 251 - 14 - - - - L.585 2,687 - - 15 - - - - 3.500 319 - - 16 - - - - .750 372 - - 17 - - - - .665 633 - - 18 - - - - .585 1,330 - - 19 - - - - 2.585 1,375 - - 20 - - - - .335 547 - - 21 - - - - .500 1,372 - - 22 - .085 54 1.415 902 - - 23 - - .085 241 .500 1,417 - - 24 .085 138 - - 1.000 1,625 Total 852 3,567 120,505 999 25 Table 1. (continued) Large Sparids Rudderfish Goatfish Wrasses Density Total Density Total Density Total Density Total Habitat Abundance Abundance Abundance Abundance 1 - .165 2 2 - - - - 4.915 10,887 - - 3 .250 461 - - 15.085 27,831 .165 304 4 - - - - 1.165 1,359 .085 99 5 - - - .335 97 - - 6 - - - 17.085 13,301 .085 66 7 - - - - .585 715 .165 202 8 - - - - 5.165 5,220 1.000 1,011 9 - - - - 5.250 1,265 .250 60 10 - - - - 8.835 53,416 .585 3,540 ll 12 - .335 251 13 - - .915 761 - - 14 - - - - 42.585 723,186 .165 280 .15 .085 8 - - 25.335 2,307 .165 15 16 .085 42 - - 6.000 2,979 2.250 1,117 .17 - - - - 9.665 9,200 1.250 1,190 18 - - - - 16.500 37,519 .165 375 19 - - - - 5.665 3,012 .335 178 20 - - - - 23.085 37,707 .335 547 21 .085 233 - - 1.585 4$349 2.085 5,721 22 - - - - 9.250 5,897 .665 424 23 - - 2.835 8,,037 2.585 7,328 24 - .250 406 3.915 6,360 1.085 1,763 Total 744 406 304,658 24,220 26 Table 1. (continued) juvenile Adult Parrotfish Parrotfish Surgeonfish Density Total Density Total Density . Total Habitat Abundance' Abundance Abundance 1 - - - - .500 4 2 .250 554 .165 365 1.335 2,957 3 10.250 18,911 .085 157 2.835 5,230 4 22.415 26,143 - - 1.585 1,849 5 2.000 582 1.165 339 6 1.585 1,234 - - .415 323 7 21.915 26,783 .085 104 3.665 4,479 8 70.415 71,162 .165 167 7.250 7,327 9 12.500 3,011 1.165 281 20.750 4,999 10 6.000 36,276 9.415 56,923 28.500 172,311 11 - - - - .915 2,970 12 - - - - 13 .085 71 - - .665 553 14 55.335 93,799 .415 703 3.915 6,636 15 30.750 2,800 .335 31 18.415 1,677 16 9.915 4,923 8.835 4,386 36.415 18,080 17 11.165 10,627 4.335 4,126 42.335 40,296 18 20.415 46,421 .165 375 6.250 14,212 19 31.835 16,928 .665 354 17.085 9,085 20 33.500 54,719 .665 1,086 29.415 48,047 21 28.915 79,340 1.250 3,430 17.500 48,018 22 22.835 14,557 10.585 6,748 47.835 30,495 23 1.415 4,011 45.415 128,750 81.585 231,292 24 2.335 3,793 10.250 16,652 81.665 132,673 Total 516,645 224,638 783,852 27 Table 1. (continued) Rabbitfish Silversides Cardinalfish Density Total Density Total Density Total Habitat Abundance Abundance Abundance 2 19.835 43,937 1.000 2,215 3 28.835 53,199 - - .165 304 4 2.835 3,306 3.335 3,890 2.250 2,624 5 1.750 509 2.500 727 - - 6 .165 128 - - 3.415 2,659 7 .665 813 - - 2.91-5 3,562 8 12.415 12,547 - - 1.165 IP177 9 1.935 442 - - - 10 .585 3,540 - - 4.335 26p2O9 11 .085 276 - - 1.250 4,058 12 - - - - - - 13 .085 71 - - 2.085 1,733 14 5.915 10,027 - - 1.750 2,966 15 7.415 675 - - .085 8 16 5.665 2,813 - - - - 17 1.000 952 - - .250 238 18 2.665 6,060 - - - - 19 13.915 7,399 - - .500 266 20 3.000 4,900 - - - - 21 9.750 26,753 - - - - 22 3.165 2,018 - - - - 23 1.915 5,429 - - - - 24 .250 406 - - .165 268 Total 186,200 4,617 48,287 28 Table 1. (continued) Blue Fusiliers Chromis Densi@t-y Total Density Total Habitat Abundance Abundance 2 3 4 5 6 7 - - 67.585 82,597 8 - - 70.085 70,828 9 - - 64.250 15,478 10 - - 335.415 11 12 - - - - 13 - - 5.000 4,157 14 - - 132.165 224,034 15 - - 269.165 24,513 16 - - 2.915 1,447 17 - - 73.000 69,485 18 - - 105.415 239,699 19 - - 1.250 665 20 - - 49.690 81,164 21 - - 574.165 1,575,454 22 - - 8.835 5,632 23 - - - - 24 2.500 4,062 - Total 4,062 4,423,070 29 Table 2. Equilibrium harvesting rates for fishes of potential economic importance in Saipan Lagoon. A B C=A/B estimated estimated estimated abundance in turnover source of yearly Saipan time turnover equilibrium Lagoon (years) time harvest sharks 277 12 Randall, 1977 23 milkfish 129 large squirrelfish 8,922 mullets 72 barracuda 20,367 1.5 DeSylva, 1963 13,578 large groupers 1,871 1.5 Thompson and Munro, 1976 1,247 slender jacks 852 1 high-bodied jacks 3,567 2.0 Watari, 1973 1,784 snappers 120,505 leiognathids 999 sparids 744 rudderfish 406 goatfish 304,658 large wrasses 24,220 2.0 Roede, 1972 12,110 adult parrotfish 224,638 surgeonfish 783,852 1.5 Randall, 1961 522,568 rabbitfish 186,200 1.5 Tsuda et al, 1976;,Hasse et al, 1977 124,133 silversides 4,617 cardinalfish 48,287 fusiliers 4,062 blue Chromis 4,423,070 1.0 Swerdloff, 1970 4,423,070 30 Table 3. Fish species observed in various habitats of Saipan Lagoon, January 1979. HABITATS SPECIFS 1 2 3 4 5 6 7 8 '9 10 11 12 13 14 15 16 17 18 CARGIIARIIINIDAE Carchazhinos melanopterus (Qttoy & Gaimard) + ORECTOLOBIDAr. Nebrius [email protected] (Lesson) + MYLIOBATIDAE Aetobatus narinari (Euphrasen) + DASYATIDAE Taeniura Lnelaij@@E @-Lla Bleeker + CIIANIDAE Chanos chanos (Forsskal) + MURAENIDAE Echidna "ebulosa (AM) + + E)Mri.othorax flavLmar&_@natus (Ruppell) C. javonicus (Bieeker) L,. meleagris (Shaw and Nedder) + C. undulatus (Lacepede) . . . + -1p. + + OPHTCHTIRDAr Myrichthys colubrinus. (Boddaett) SYNODONTIDAE Saurida. gracilis (Quoy and Gaimard) + + + + Table 3 . (continued) IIABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 Il 12 13 14 .1.5 16 17 18 1 BE-10NIDAE spccjps A (I.argc; SqonUL,,ra?) species 13 (stliall) + + unidpntified halfbeaks + + HOLOCEINTRIDAF Adi@jryx dizjd@mLi (Lacepede) + + 4- + A. spiniler (Forsskql) + + AdJoryx sp. + Flaii,imeo 1,-.ievis (Gunther) + 2_E(@i ul@ s (Valenciennps) + + . @ca r i @ T. sammara (Forsskat) . . . . + + + + + @s adustus Bleeker + -H. amaenus (Castlenau) + + + M. @!@an (Forsskal) + + + + + + -ff. violaccus Bleeker + AULOSTOMIUAE Aulostomus chinensis (Linnaeus) + FISTULAR11DAE Fistularia commersont Ruppell + + + + + SYNCNNI'111DAE Cory 0ioichthXs intestinalis (Ramsay) + + + + + Doryramphus melanopleura (Bleeker) + + + ATHERINIDAE Unidentified silversides + + MUGILIDAE unidentified mullet + Table 3 . (continued) @rAT%7--- SPECIES 1 2 4 5 6 7 8 9 1-0 '11 12 .13 14 1 _5 1. 6 17 1 A 2 S PHY RAE,N1 DA E' a@ljy a-na barracuda (Wal.baum) S. chinensis Lacepede SCORPAENIDAE Dendrochtrus _@rach@yL@rus (Cuvier) + S:co@@[ja(@nodes pjamensis (Quoy and Gaimard) + + + Scorimenopsis diabolus (CLIVier) + APOGONJDAE AijoB@Ln co-ccincus Ruppell + + A. exosti_gLna Jordan and Starks + A. -@a_.L.1cj)LeUtis Bleeker + W. [email protected] Cuvier & Valenciennes . . . . . . . . + + A. nu.bilis Garman + + + A. sa4mriensis Fowler + --- ---- &0 LO ilic-0-11 S 1) . + + + + + LJ Spp. + + + + + + @'[email protected])terus macrodon (Lacepede) + L --- Param.a quinSluelineaLa (Cuvier & Valenciennes) + + + + + + + + Siphainfa sp. + h,jm1phe Lj@ m4@rra (Bloch) + + + 1,UT,IANtf)Al-'. &L@hmrcu-@@ ur@Fjtus (Lacepede) A[jrjon virescens Cuvier and Valenciennes + Lutjanus bohar (Forsskal.) L. folvus (Schneider) 4 + + + + + + L. kasmir'l (Forsskal) + + + L. monosL (Cuvier and Valenciennes) + + Ll 9R-11 .1-3 inus sp. + + + + Table 3 . (continued) IIABT.TNrS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 1-3 14 15 16 17 18 19 LETHRINIDAE Gn-ILhodentex aureolineatus (Lacepede) + Lethrinus harnk (Forsskal) + . . . + + + + + L. miniat-u,3 (Bloch and Schneider) -L. r.am,'ik (Forsskal) + + + Y@[email protected],L--s sp. + + + + + + + LoUirinus juveniles klacolor nLger (Forsskal) + Ll(@no@iixir _aLmdoculis (Cuvier and Valenciennes) + + NEMIPTERIDAE Scolopsis cancellatus (Cuvier and Valenciennes) + CAESTONIDAE Coesio cacrulaureLiq Lacepede CARANCIDAE LJ Caranx mel@!mjiy_gjiq Cuvier + + + _pf-_capLe@Lus pt s (Eydoux and Souleyo-) Scumberoides lysan (Forsskal) + + + Trnchinotus bailloni (Lacepede) + KYPIIOSIDAR EM@iosus cinerascens (Forsskal) + MULLTDAE, flavolineatus (Lacepede) . . . + + . . . + + + M. vinivolensis (Valenciennes) + + E@j @aerLem- barberinus (Lacepede) . . . . . . . . . . . . . . . . . P. bifascLntus (Lacepede) + P.. cyclostomus (Lacepede) + + + + + L. pleurc@sLigma (Bennett) + . . . . . P. trifasciatus (Lacepede) + + + . . . . . spilurus (Bleeker) + Table 3. (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 CIRRHITIDAE Cirrhitus pinnulatus (Schneider) Neocirrhites armatus (Castlenau) Paracirrhites arcatus (Cuvier) + P. for.steri (Schneider) + LE10,GNATHIDAE [email protected] argyreus Cuvier and Valenciennes . . . + + CHAETODONTIDAE Chaetodon auriga Forsskal + + . . . . . . . . . + + + C. bennetti Cuvier and Valenciennes + + citrinellus Ctivier and Valenciennes + + + + + @Llj@jjpLum Ctivier and Valenciennes + + + + . . . + C. kleini Bloch + T. -fin-ul7i 1,ncepede + + + + 4. . . . . . Ln ;e-IL-n-noLus Bloch and Schneider + + mertensli-CLIvier + C. ortlatiss-imus Solander + + + C. pqn@t @@tofasciatus Ckivier giiadrimaedlatus Gray- C. reticulatus Cuvier + @-rifas-ciatus Mungo Park . . . . . . . . C. ujietensis Cuvier and Valenciennes . . . + + C. till jM,@Cjla t US Bloell + + Forcipiger. flavisslinus Jordan and McCregor Heniochus c Cuvier . . . . . . . . . . Megapro.todon trifascialls (Cmelin) + + POMACANTHIDAE Centropyge flavissimus (Cuvier and Valenciennes) + Pomacanthus imperator (Bloch) + + + Table 3 . (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 1-1 12 13 14 15 16 17 18 19 POMACH,NTRIDAE AbUdefduf vaigiensis (Quoy and Gaimard) + + A. + A. [email protected] (Lacepede) + + + + + + + A. sordidus (Forsskal) + ,@@iprion clarkii (Bennett) + A. Telanopus Bleeker + + . . . + Chronils atripectoralis Welander and Schultz + + + + C. caerulea (Cuvler) . . . . . . . . . . . C. ELr.@@!_ritifer Fowler + Chromis xanthura (Bleeker) + Dascyllus arunnus (Linnaeus) . . . . . . . . . . . . . . . . D. reticulatus (Richardson) + D. trimaculatus (Ruppell) + + + + + + + fup-omace-n-trus albifasciatus (Schlegel. and Muller) . . . . . . . + + + + + E. fasciolatus (Ogilby) + + + E. lividus (Bloch and Schneider) + + + + E. nigricans (Lacepede) + + + . . . . . . Glyphidodontops glaucus (Cuiver and Valenciennes) + + + G. leucopomus (Lesson) + + + + + + Plectroglyphidodon dickii (Lienard) + + imparipennis (Vaillant and Sauvage) johnstonianus Fowler and Ball . . . 1@. jachry (Quoy and Caimard) + lita t us P. leucozona (Bleeker) + + 1@. _phoi@nixerjsis (Schultz) Pomacentrus pavo (Bloch) + + . . . + + + + + P. vaiuli Jordan and Senle + + + + . . . . . . uni@-enCT-Tied pomacentrid + LABRIDAE Anampses caeruleopunctatus Ruppell + A. twisti Bleeker + 'jod-janus axillaris (Bennett) Cheilinus chlorurus (Bloch) + + + . . . . Table 3 . (continued) HABITATS SPrCIIIS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 .16 17 .18 19 C. L)@@ Bleeker + + + + C. rhodochrous Cunther + + + C. Crilobatus Lacepede + + + + . . . + + C. imdUlatus Ruppell + . . . @11- CLJHI@17@p - + + + + Cheilio inermis (Forsskal) . . . . + + + + + + + '5ici-rrhila-br-us- sp. + @ori@s aya!ila Lacepede + C1. &jqi@t@nadi (Quoy and Gaimard) + + Cymolutes praetextatus (Quoy and Gaimara) + + + + + I@L)Lb @Im@ insidiator (Pallas) + + @@m jiost@7- varius Lacppede + + + + + lialichoorcs c@ntriq@j @rus (Lacepede) + + + U. hartzfeldi (Bleeker) + H. mqrgii@ita@eou- (Cuvier and Valenciennes) + + + + + @jarLj.!j._ituq_ Ruppell + + 11. trimaculatus (Qtjoy and Gaimard) . . . . . . . + + + + + + . . . . Ilemigymnus fasciatus (Bloch) + + + H. t (9) och) + + . . . + + LLibrAcht s tLn . ineatus (Guichenot) + Labroides bicolor Fowler and Bean + L. diRlidiat(LS Cuvier & Valenciennes . . . . . . . + + + 4 Macro haryngodon meleagris (Cuvier and Valenciennes) + rscudocheilinus evanidus Jordan and Evermann + fseu(Lo juloides cerasinus-, (Snyder) -9tetLiojLijj,,.;- band@Tn-ensis (Bleeker) + + + + + + . . . . + + + + _@. StrigivenLer (Bennett) .@tetho @!Iis jilveniles + + + + L _ Thalassoma amt@ycejLh@iLa (Bleeker) + T. fuscum (Lacepede) + T. Ti-ar(Tw-icke (Bennett) + . . . . + 7. i'utescens (Lay and Bennett) + + + 4 1- . . . T. p2jpuremn (Fnrsskal) + R@Llqque'@ittata (Lay and Bennett) + + Xyrichtys macrolepidotus (Bloch) + Table 3. (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 .1. 5 1.6 17 1-8 1. X. taeniourus (Lacepede) + + + + . . . . . unidentMed labrid A + unidentified labrid B + unidentified labrid C SCARIDAE Calotomus -spkni@ens (Quoy and Gaimard) + Cetoscarus bicolor (Ruppell) Scartis chLji2rc!@on Jenyns . . . + + @-.fo-rs-L@xi Cuvler and Valenciennes + + + S. sexviLtatus Ruppell 2jiobban Forsskal + + + + + + + + + S. globiceps Cuvier and Valenciennes S. harid Forsskal + S. jonesi Streets 9. rtibroviolaceus (Bleeker) S. -@r-(ffdus Forsskal . . . . . . . . . . . . . S. venosus Citvier and Valenciennes + 00 ScariLq sp. + + + + + juvenile. scarids . . . . . . . . . . . . . . . . MUGILOIDIDAE Parapercis cephalopunctata (Seale) + + P. clathrata Ogilby ACANTHURIDAE Acanthurus achilles Shaw A. gLaucopareius Cuvier + A. guttatits Bloch and Schneider 'K. lineatus (Linnaeus) + . . . X. Za-C;@-07iv-ier and Valenciennes + + + + + . . . + + + nigrofUSCUs Forsskal + + A. olivaceous Bloch and Schneider + + + + pyroferus Kittlitz Table 3 . (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 it. triostegus (Linnaeus) + + + + + . . . A. xanthopterus Cuvier and Valenciennes . . . . . . . . . . + Ctenbchaetus striatus Cuvier and Valenciennes . . . + + + Naso brevTr-oqtris Valenciennes + + + + + + + N. literatus. (Bloch and Schneider) . . . + . . . . . N. tuberosus (Lacepede) N. unicornis (Forsskal) + + + + + + . . . K. s - + j,.v.nil.s Zebrasoma flavescens (Bennett) . . . . . . . . . Z. velifer.. (Bloch) + + + ZANCLIDA9 Zanclus cornutus (Linnaeus) . . . . . . . . . SIGANIDAE Siganus argenteus (Quoy and Gaimard) + + + . . . + + + + S. punctatus (Bloch and Schneider) + S. spinus (Linnaeus) . . . . + + + + + . . . . + @i&@nus sp. + MICRODESMIDAE Gunnelichthys monostigma Smith BLENNTTDAE Exallias brevis (Kner) Meiacanthits atrodorsalis (Gunther) + + . . . TI-etrosJrtes breviceps (Bleeker) + P. mitratus Ruppell + Plagiotremus tapeinosoma (Bleeker) + + Salarias fasciatus (Bloch) + + CALLIONYMIDAE Diplo&rammus goramensis (Bleeker) + Table 3. (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 1 GOBIIDAE Acentrogobius ornatus (Ruppell) + + + Ambly&obius albimaculatus (Ruppell) + + + + + + Fusigobius neophytus (Gunther) + + + + Gnatholepis sp. + + + Paragobiodon echinocephalus (Ruppell) + unidentified gobiids + + ELEOTRIDAE Asterropteryx semipunctatus Ruppell + + Po n cu ius zebra Fowler pt:o reMtris evides (Jordan and Hubbs) P. microlepis (Bleeker) + + + + Valenciennes strigatus Broussonnet + + + + BOTHIDAE Bothus mancus (Broussonnet) + + + SOLEIDAE Aseraggodes melanogtictus (Peters) + BALISTIDAE Balistoides viriaescens (Bloch and Schneider) + + Melichthys vidua (Solander) Rhinecanthus aculeatus Linnaeus . . . . . . . + + . . . . + + ,@. rectangulus (Blocif and Schneider) + + + + Sufflamen bursa (Bloch and Schneider) chrysoptera (Bloch and Schneider) MONACANTHIDAE Alutera scripts (Osbeck) Amanses scopas (Cuvier) Cantherines dumerilli (Hollard) @@. pardalis (Ruppell) + Oxymonacanthus longirostris (Bloch and Schneider) + + + + + Tahle 3 (continued) HABITATS SPECIES 1 2 3 4 5 6 7 8 9 10 11 12 1.3 14 15 16 17 18 1 OSTRACIONTIDAE Lactoris fornasini (Bianconi) + + ___racion cubicus Linnaeus + + + 0. meleagris Shaw + TETRAODONTIDAE Arothron hispidus (Linnaeus) + + + + 4. + @C -immaculatus (Bloch and Schneider) + 7A. nigrqpLtrlctaL@@s (Bloch end Schneider) + + + Arothron sp. + Canthigaster solandri (Richardson) . ... . . . . . . . . . . + + Total Species in Habitat (excluding unidentified 7 37 47 41 30 26 52 74 31 .56 31 8 22 68 84 90 77 50 6 juveniles in habitats where appropriate aduLt forms were seen) IThis species has often been erroneously identified by recent aut:hors as EX!mcjth(@rax thyrsoideus (Richardson). Randall (1973 undescribed. Two specimens were collected and will be deposited in the University of Guam Marine Laboratory (UGML) Fish 21"dentifications of barraCUdas are tentative. The species identified as @@,@aenn chtnensis Lacepede has beencollected oil Gil University of Guam Marine Laboratory (UGML) Fish Collection. 3This species was tentatively identified by Lachner in Schultz et al. (1953) as Apopgon n e;@L nov i I Valencterines but may be un 41dentification is tentative. 5This species will be described by John Shepard. 6Randall and Mange (1978) provided this name for this Indo-Pacific surgeonfish which has been erroneously kiiown as Acanthurus EiLi@Li(@Ltn, (Lacepede) in recent literature. No author designation was given. 7This individual was seen momentarily and is Probably one of the above three species. It is not counted -In tile total species Lagoon. Table 4. Individual and total zooplankton densities for horizontal surface tows in Saipan Lagoon in Janu Density (Individuals/m3) Taxon 1 2 3 4 5 6 7 8 1 9 10 11 12 13 14 1 Fish eggs 54.8 1.2 26.0 66.4 15.7 2.1 3.5 1.3 3.0 18.5 1.0 5.1 10.3 0.7 26 Fish larvae <0.1 0.1 0.2 0.1 <0.1 <0.1 <0.1 0.4 0.3 3.1 0.1 <0.1 0 Copepods 0.1 0.1 2.1 13.9 0.4 0.3 0.7 1.0 0.8 1.1 117.6 485.1 2-.4 0.4 0 Brachyuran zoeae 1.1 0.4 0.9 0.3 1.3 0.5 0.1 0.4 4.8 1.0 15.8 0.7 0.2 0 .Shrimp larvae 0.2 0.1 1.4 0.1 0.2 0.11 0.1 4.2 6.1 32.51 1.7 0.2 0 Chaetognaths 0.1 0.5 0.1 <0.1 0.1 <0.1 2.2 13.6 52.4 1 <0.1 Larvaceans <0.1 0.3 0.1 0.1 0.3 30.2 25.41 <0.1 I Foraminifera 0.1 0.2 2.5 0.3 0.5 1.0 0.2 0.7 1.2 0.4 0.7 1.01 1 Gastropod larvae 0.6 0.2 , 0.4 0.2 <0.1 0.1 <0.1 1.4 9.2 0.2 1 Bivalve larvae <0.1 Medusae <0.1 0.3 Pagurid megalopas <0.1 Lucifer 0.3 1.5 Insects <0.1 0.1 <0.1 0.1 Mysids <0.1 0.5 0.1 0 Ascidian tadpoles <0.1 <0.11 0.2 <0.1 Radiolaria <0.1 0.1 <0.1 <0.1 0.1 <0.1 0 Polychaetes <0.1 <0.1 <0.1 <0.1 Heteropods <0.1 1@sopods <0.1 0.1 0.1 <0.1 Egg case <0.11 <0.1 <0.1 Amphipods 0.1 0 Stomatopod larvae 0.5 Nauplii <0.1 Cumaceans <0.1 Misc. worms <0.1 <0.1 Misc. unknowns <0.1 <0.1 0.2 0.1 0.1 <0.1 0.1 <0. 0.2 0 TOTAL 57.0 2.1 32.0 83.5 19.0 3.8 5.4 3.6 5.8 33.9 171.1 631.6 16.0 1.7 30 -7 9 3 4 /17 6 Figure 1. Locations of zooplankton tows in 15 Saipan Lagoon, January 1979. 43 PLATE I SAIPAN LAGOON FISH HABITATS A. Habitat 1. Silty inlet lined with mangroves and under influence of freshwater runoff, north of Charlie Dock. Average Depth, 0.5'm. B. Habitat 2. Thick patches of the seagrass, Enhalus acoroides surrounded by fine sand, adjacent to Achugau Beach, 1.3 m. C. Habitat 3. Vast expanse of the seagrass Halodule uninervis south of Susupe Point, 1.3 m. D. Habitat 6. Coarse sand with scattered rocks covered with the alga Sargassum poly_qystum, Susupe Point, 1.5 m. E. Habitat 8. Extensive patch reef consisting mainly of dead coral covered with Caulpera racemosa and other algae and scattered living heads of the coral Pocillopora damicornis. About 800 m north of Flores Point. 1 m. F. Habitat 8. Some large examples of the soft coral Sarcophyton tracheiliqphorum, 1 m. G. Habitat 9. Shoreline south of the power barge with sub- strate consisting of rocks and scrap metal overgrown with the coral, Pocillopora damicornis, 3 m. H. Habitat 10. Tanapag Harbor in the vicinity of the north- east mooring buoy. Substrate consists of fine sand with scattered living coral patches, primarily Pocillopora damicorni's, 12 m. The fish in the center is the goatfish, Parupeneus trifasciatus. 44 'r77: 1-14Q, .@001'-'- cqll Aw Zk. ,lit 4-A i - - - - - ----- PLATE II SAIPAN LAGOON FISH HABITATS A. Habitat 10. Tanapag Harbor in the vicinity of the north- east mooring buoy. A vast sandy plain at 12 m. B. Habitat 10. Tanapag Harbor in the vicinity of the north- east mooring buoy. A patch reef area at a depth of 10 m. C. Habitat 12. Flat sandy plain covered with a mat of the blue-green alga, Microcoleus lyngbyaceus, 1.1 km west of Dogas Point, northern Tanapag Lagoon, 3 m. D. Habitat 12. Another view of the area shown in C. E. Habitat 13. Coarse sand with scattered algae and holothurians, central Garapan Lagoon, 2.5 m. F. Habitat 13. Coarse sand with scattered holothurians and several goatfish, Mulloidichthys flavolineatus, central Garapan Lagoon, 2.5 m. G. Habitat 14. Coarse sand interspersed with patches of Acropora, Garapan Lagoon, 1.5 m. Several small parrot- fishes and two goatfish, Parupeneus barberinus can be seen. H. Habitat 14. Patches of the corals Acropora and Porites, Garapan Lagoon, 1.5 m. 46 INN 7- A---Mm pw .MIT- zn X'. -40% W6 PLATE III SAIPAN LAGOON FISH HABITATS A. Habitat 15. Large p4tches of the coral Acropora formosa near the proposed fisheries complex, northern Garapan Lagoon, 2 m. The fish at left are squirrelfish, Flammeo sammara. B. Habitat 15. Large patch of the coral Acropora formosa nearly 2 m thick, northern Garapan Lagoon, 2.5 m. The fishes are the goatfish, Parupeneus spilurus and the snapper Lutjanus kasmira. C. Habitat 17. Patch reef on the west side of Managaha Island, 2.5 m. D. Habitat 17. Edge of a patch reef on the west side of Managaha. Island, 3.5 m. E. Habitat 18. Area of coarse sand, rubble and small pieces of living Acropora corals about 300 m north of Dogas Point, northern Tanapag Lagoon, 1.5 m. F. Habitat 18. Coarse sand with large scattered mounds of dead and living coral adjacent to the area shown in E. G. Habitat 20. Large expanses of Acropora spp. and other corals interspersed with sand and rubble patches, immediately inshore of the exposed reef flat, northern Tanapag Lagoon. 48 A' -tip, 14 777 J,F PLATE IV SAIPAN LAGOON FISH HABITATS A. Habitat 20. Large expanses of coral, mainly Acropora spp., immediately inshore of the exposed reef flat, northern Tanapag Lagoon, 0.7 m,. The tops of these corals are exposed during the lowest tides. B. Habitat 21. Large expanses of Acropora spp. and other corals with scattered patches of rubble and coarse sand, outer edge of Garapan Lagoon, 1 m. C. Habitat 22. Submerged reef crest of eroded limestone dissected by sand channels, northeast edge of Garapan Lagoon, 1.5 m. D. Habitat 22. Area adjacent to that shown in C. E. Habitat 23. Surge zone at extreme upper portion of spur and groove 'zone at the reef margin immediately north of Afetna Point, I m. F. Habitat 23. Reef margin at'the lower portion of the spur and groove zone immediately north of Afetna Point, 4 m. Fishes seen are the surgeonfish Acanthurus guttatus, A glaucopareius, and Naso unicornis and the pariotfish, Scarus sordidus. G. Habitat 24. Reef margin off the northern end of Garapan Lagoon, 3 m. Several species of surgeonfish and parrot- fish can be seen. H. Habitat 24. Coralline algal reef dissected by deep, cavernous sand channels and holes, outside the northern end of Garapan Lagoon, 10 m. The fish in the upper portion of the photo are the parrotfish, Scarus sordidus. 50 El Or.: 7- kp PLATE V REEF FISHES OF POTENTIAL ECONOMIC IMPORTANCE A. Family Holocentridae, squirrelfish. Flammeo opercularis, .about 16 cm standard length, outer Ga7rapan Lagoon, habitat 21, 1.6 m. B. Family Mugilidae, mullets. Plicomugil-lobiosus about 13 cm s.l., Enewetak Atoll, Marshall Islands. mullet, similar to these were seen only in very shallow water adjacent to the shoreline in habitats 1 and 3 or in the surf zone of habitat 23. C. Family Sphyraenidae, barracudas. Sphyraena helleri, about 35 cm s.l., Kawaihae, Hawaii, a small species possibly identical with those seen in habitat 7. D. Family Apogonidae, cardinalfish. Apogon sp., about 3 cm. s.l., 2.5 m, habitat 13. E. Family Serranidae, groupers. Epinephelus merra, about 18 cm s.l., Guam. F. Family Kuhliidae, flagtails. Kuhlia taeniura, 9.4 cm s.l., from a tide pool at Afetna Point. G. Family Kyphosidae, rudderfish. Kyphosus cinerascens, about 18 cm s.l., Kona Coast, Hawaii. H. Family Carangidae, jacks. The common high-bodied jack, Caranx melampygus, about 60 cm s.l., Enewetak Atoll, Marshall Islands. 52 --7-77 IJA r7 PLATE VI REEF FISHES OF POTENTIAL ECONOMIC IMPORTANCE A. Family Carangidae, jacks. One of the slender jacks, the leatherback, Scomberoides lysan, about 25 cm s.l,, Guam. B. Family Lutjanidae, snappers. The red-snapper, Lutjanus bohar, about 58 cm s.l., in a fish trap off Guam. This, one of the largest species of reef snappers,was observed only outside the lagoon, in habitat 24. Large specimens may be responsible for ciguatera poisoning. C. Family Lutj@Lnidae, snappers. Lutjanus sp., about 10 cm s.l., 12 m. Tanapag Harbor, Habitat 10. D. Family Lutjanidae, snappers. Aprion vire9cens, about 25 cm s.l., Oahu, Hawaiian Islands. This highly prized food fish reaches a length of 1 m and was seen only in the deepest part of Tanapag Harbor, habitat 10. E. Family Caesionidae, fusiliers. Caesio xanthonotus, about 16 cm s.l., Enewetak Atoll, Mars 11 Islands. F. Family Lethrinidae. Lethrinus harak, a juvenile about 10 cm s.l., over the seagrass, Halodule uninervis, 1.5 m, habitat 2. G. Sparid, Monotaxis grandoculis, a juvenile about 10 cm s.l., Oahu, Hawaii3n Islands. H. Family Leiognathidae, Mojarras. Gerres argyreus?, 19.0 cm s.l., Guam. 54 ........... OL NOEL PLATE VII REEF FISHES OF POTENTIAL ECONOMIC IMPORTANCE A. Family Mullidae, goatfish. Parupeneus barberinus, about 11 cm s.l., 1.5 M, Susupe Point, habitat 6. B. Family Pomacentridae, damselfish. A typical aggregation of Chromis caerulea, above staghorn coral, Acropora formosa, 1 m, habitat 15. C. Family Pomacentridae, damselfish. Chromis caerulea, about 4 cm t.l., 2.5 m, habitat 13. D. Family Labridae, wrasse. Cheilinus trilobatus, about 10 cm t.l., 1.5 m, Managaha Island, habitat 16. This species reaches a total length of 35 cm. E. Family Labridae, wrasse. Xyrichtys taeniourus, about 10 cm s.l., 1.5 m, Managaha Island, habitat 16. This species reaches a total length of 25 cm. F. Family Scaridae, parrotfish. Scarus ghobban, 7.8 cm s.l., from a seagrass (Enhalus acoroides) bed, 1.5 m, habitat 2. G. Family Acanthuridae, surgeonfish. Acanthurus lineatus, about 20 cm s.l., Enewetak Atoll, Marshall Islands. This is the most abundant surgeonfish along the upper edge of the reef margin of Saipan Lagoon. H. Family Siganidae, rabbitfish. Siganus spinus, 12.0 cm s.l., from a seagrass (Enhalus acoroides) bed, 1.5 m, habitat 2. 56 4V A d" an 010 -L'i nh i u Key to Color Maps B = Blue, G = Green, Y = Yellow, 0 = Orange, R = Red Densities in number per 1000 m2 1. Habitats: B = Habitat 1, G = Habitat 2, Y = Habitat 3, 0 = Habitat 4, R = Habitat 5 2. Habitats: B = Habitat 6, G = Habitat 7, Y = Habitat 8, 0 = Habitat 9, R = Habitat 10 3. Habitats: B = Habitat 11, G = Habitat 12, Y = Habitat 13, 0 = Habitat 14, R = Habitat 15 4. Habitats: B = Habitat 16, G = Habitat 17, Y = Habitat 18, 0 = Habitat 19, R = Habitat 20 5. Habitats: B = Habitat 21, G = Habitat 22, Y = Habitat 23, 0 = Habitat 24 6. Sharks: R = >.068=.085 7. Large Squirrelfish: B = >0-3, R = >12-15 8. Large Groupers: G = >.05-.10, R = >.20-.25 9. Slender Jacks: B = >0-.12, R = >.48-60 10. High-bodied Jacks: B >0-2.5, R = >10.0-12.5 11. Snappers: B = >0-4, Y >8-12, R = >16-20 12. Leiognathids: G = >.15-.30, Y = >.30-.45, R = >.60-75 13. Sparids: G >.05-.10, R = >.20-.25 14. Goatfish: B >0-9, G = >9-18, Y = >18-27, R = >36-45 15. Large Wrasses: B = >0-.6, G = >.6-1.2, Y = >1.2-1.8, O= >1.8-2.4, R = >2.4-3.0 16. Juvenile Parrotfish: B = >0-15, G = >15-30, Y = >30-45, 0= >45-60, R = >60-75 17. Adult Parrotfish: B = >0-10, G = >10-20, R = >40-50 18. Surgeonfish: B = >0-17, G = >l7-34, Y = >34-51, R =>68-85 19. Rabbitfish: B = >0-6, G = >6-12, Y = >12-18, 0 = >18-24, R = >24-30 20. Silversides: 0 = >2.1-2.8, R = >2.8-3.5 21. Cardinalfish: B = >0-.9, G = >.9-1.8, Y = >1.8-2.7, 0 = >2.7-3.6, R = >3.6-4.5 22. Blue Chromis: B = >0-120, G = >120-240, Y = >240-350, R = >480-600 23. Number of Fish Species: B= >0-20, G = >20-40, Y= >40-60, 0 = >60-80, R = >80-100 58 US Department of Commerce NOAA Coastal Services Center Library 2234 South Hobson Avenue Charleston, SC 29405-2413