/by Karen Mauck & John Fletemeyer. . Mauck, Karen. Fletemeyer, John. Florida.Office of Coastal Zone Management. [Tallahassee, Fla.:Department of Environmental Regulation, Office of Coastal Zone Management,1986?] Sea turtles Florida Delray Beach. Cheloniidae Florida Delray Beach. Leatherneck turtle Florida Delray Beach. Loggerhead turtle Florida Delray Beach. Green turtle Florida Delray Beach. Environmental monitoring Florida Delray Beach. 1986 Delray Beach Sea Turtle Conservatin Report - BY - Karen Mauck & John Fletemeyer Funding for this project was provided by the Department of Environmental Regulation, Office of Coastal Management, using funds provided through the Coastal Zone Management Act of 1972 administered by the National Oceanic and Atmospheric Administration. QL 666 .C536 .M38 1986 US Department of Commerce NOAA Coastal Services Center Library 2234 South Hobson Avenue Charlestono SC 29405-2413 IIN@rPZOIDUC@r:EON The sea turtle is an exceedingly complex lifeform which is poorly known throughout most stages of its natural history. Once sea turtles were abundant, inhabiting much of the tropical and sub-tropical waters of-the-world, but today this is no longer the case. Now most populations of these reptiles have been diminished by a variety of natural and human pressures, and their total population is much smaller than it was only a few decades ago. This drastic decline of sea turtles has made it necessary to declare all seven species of sea turtle as 'either "threatened" or "endangered". The Atlantic loggerhead sea turtle (Caretta caretta carettaj which is the focus of this conservation program;holds an endangered species status under the the I.U.C.N. (1970) and a "threatened" species status under the Federal Endangered Species Act. Considering this most marine biologists consider the sea turtle to be one of world's most over-exploited animals (King, 1979). There are many reasons for the alarming decline of sea turtles. Some are natural and are the result of a variety of marine, avian, and terrestrial animals @that are predators of hatchling and juvenile animals. Other problems related to man and his attempts to develop and sometimes exploit the coastal zone. Condominiums, hotels, private residences, and associated heavy pedestrain traffic seriously impact many important nesting beaches in the United States and other parts of the world. Artificial lights associated with development compound this problem by confusing baby turtles as they emerge from their nests, often causing them to head in the wrong direction away from the sea. Frequently hundreds of baby sea turtles are seen squashed along the roadside. Their carcasses, lying in stench and decay, bear mute and dramatic testimony to what is becoming of the sea turtle. There are other problems which are not discussed in the text of this report. Figure 1 represents a model which depicts most of the sea turtle's survival problems. 71CHIE PRIESIEN73C SrEUD-Z The Delray Sea Turtle Conservation program was initiated when a beach --*and-- renourishment project was conducted on the public beach during the summer of 1984. Due to the discovery during the first year of this projpct that a large sea turtle population nested on Delray Beach (Figure 2), it was unanimously decided by the City Council- to continue this program during the 1985 and 11986 seasons. This report represents a descriptive summary of the results of this summe-PlZ conservation effort and a comparison of the nesting data obtained over the three sasons this program has been in operation. MIE'ICHODS Nesting surveys were conducted between 1 May and 31 August, between \n 6:30 A.M. and8:30 A.M each mornii.: An initial survey of the beach each .-9" morning which involved making a reconnaissance along the entire length of the beach using a Yamaha 175 ATC. Whenever a sea turtle crawl was 1fi observed, it was recorded on a data form. 'It the crawl resulted in a nest, it was marked with an identification stake. After the first survey was concluded, a second survey was conducted to relocate the nest stakes'.. A majority of nests were promptly excavated and relocated to the artificial hatchery located on the beach 300 yards north of Atlantic Blvd. TERkE'STRIAL STAGES Rat s Fox es Vegetation Roots Riprap Pa-ccoon-S Ants G.host Crabs Burrowing Worms :oastal Construction Beach Erosion NESTS ............. .. Artificial Lights ............... Poaching Birds Beach Penourishment NESTING FEMALES Pedestrian Traffic Beach Cleaning Equipment HATCHLINGS LAN -SEA INTERFACE Senility ADULTS Predatory Fish Incidental Capture Boat Runovers Poaching JUVENILES (SUB-ADULTS Oil Contamination Disease Severe Weather D 3 DB-ADULTS Fig. 1 PELAGIC STAGES HYPOTHETICAL MODEL DEPICTING NATURAL AND HUMAN DISTURBANCES RESPONSIBLE FOR REDUCING SEA TURTLE POPULATIONS AT VARIOUS STAGES OF THEIR NATURAL HISTORY OtAtLAPIASSIN JACKSONVILLE A rLANrIc IT111-F - or mzlrfco OCZ'A N ORLANDO TAMPA PA@Z WW PALAII BEACH BEACH 00WIry IDURAY BEACH MIAMI MARTIN CO TY q dlk. 01 Ave. 0)(EECHOS WEST PAW BEACH SR so CF DELRAY BEACH SCOW. I C LANO BEACH FIGURE 2:, Locatign of the Delray Beach Sea Turtle Conservation Proejct. The reason f or leaving a small number of nests on the beach was was to determine if the nesting success of the relocated nests was similar to that of natural nests. In order ensure the protection of the natural nests, they were marked with ID ",steaks. Also the only area where natural nests were lef t on the beach was the area where private homes were located. This helped to eliminate problems dealing with Oedestrain traffic associated with the public beach area. When a natural nest or a relocated nest hatched, the contents of the nests were examined according to the following criteria: 1. Total No. of eggs in the clutch 2. Total No. of unhatched eggs 3. 'rotal No. of eggs to successfully hatch 4. Total No. of pipped eggs with dead hatchlings 5. Total No. of pipped eggs with alive hatchlings 6. Total No. of dead hatchlings observed in the nests 7. Total No. of days it took nest to hatch After the above nest hatching data was recorded, the hatchlings from each nest were immediately transported to the water's edge in plastic buckets. The, baby turtles were then allowed to crawl about 10 feet down the beach before swimming out to sea. In most cases turtle releases were conducted as early as possible, usually between the hours of 7:00 A.M. and 8:00 A.M. :PU:BI-JEC IEIDUGA@ICJEON Since a major objective of this program was to educate the public about the surv3'*.v*al status and natural history of the sea turtle, numerous attempts were made to invovle the public with this program. This was achieved in the follwing ways: 1. Special educational brochures were distributed to the public. 2. Special "Please Keep Lights off the Beach" bulletins were dis- .tributed to private residences and condos'i located on the beach. 3. The public was encouraged to participate in the early morning baby sea turtle releases. n1F-SUI.rrS During the 1986 turtle season, nesting activity on Delray Beach lasted 107 days, beginning on 1 May with a loggerhead sea turtle nest and ending on 16 August with a nest from the same species. In comparison during the 1985 season nesting last 110 days, and during the 1984 season nesting lasted 105 days. This season a total of 355 turtle emergences were observed on Delray Beach. From this total, 150@ of these emergences represented nests. This represents a nesting success of '49%. The total numer of emergences and the computed nesting success is compared for the last three seasons (1984-86) is presented in table 1. Table 1: Comparison of nesting success and the total number of .,emergences on Delary Beach during the past 3 seasons. YEAR NO. of NESTS No. of NESTING FALSE CRAWLS SUCCESS 1984 218 202 55% 1985 156 224 41% 1986 150 205 49% To determine if nesting on Delray beach is increasing or decreasing over the last three seasons, the total number of nests observed on the beach for each year was subjected to a regression analysis. Results of this analysis revealed a trend toward a decrease (Figure 3). However, the P value = .141 indicates that this is not a highly significant trend. *It should be noted that three years of data is not enough to discern any long term trends in sea turtle nesting. H :L -t-t ir ca- 116 w alfflIff I c3 E I*J ta- --3 t-- :L ri Da -t-- -a 0 xr ca- jr t: la k, z@- 1-1 -jr f -=. Old M.1 W a I -13 -A 45 C> rl _C3 JOIN I ON AIR I 16" 1 r"2 L ON if 11111 LMMA Uw%r I 210116 1 aw@d I 06= AAA I =%M if laid IN M%M 121`1111 MMM M%M M%M M%w 161011 M%w Mir In I Iwo= I r m 116 1A lw 0=6= I lin I =%= * 0 &WW 1 MM6M 6+ * v16 1 1101sl! I ,r r I L M I AN MWN I RA I or i laid r M64 I r=M1 I JR6 Mw 1 16 4 1611 lm IN ww L A n I I 41110 111 now= 2 M a 910 1 MIA 10 A In, r I MIAM I MIA I jAn Jwv d6JV A &Ifww &JWW V11 a T% w IN! 1611 w 0 11,61111 1% A @Mwww Would you like to see the table of statistics (Y/N)? y T = 2.103 STANDARD DEVIATION OF X VARIABLE = I P = .141' STANDARD DEVIATION OF Y VARIABLE = 37.6475 SLOPE OF REGRESSION LINE -34 STANDARD ERROR OF SLOPE 16.1658 Y INTERCEPT OF REGRESSION LINE = 67664.7 REGRESSION COEFFICIENT (R) = -.903115 Would you like to do more platting? The peak nesting -month was June lUg.4). June also was the peak month during the 1984 and 1985 seasons. During the past three seasons, the month with the least number of nests observed was August. From the total number nests observed on Delray Beach all but one belonged to Atlantic loggerehead sea turtles, Caretta caretta caretta. The once, exception was a leatherback sea, turtle, Dermochelys coriacea, nest which made on the north end of the public beach on June 8. No green sea turtle, Chelonia mydas, nests were observed during the 1986 season. Nesting broken down by species: is compared in Table 2 for the last three seasons. Table 3: Nesting Broken Down 13Y Species Compared Over The Last Three Seasons on Delray Beach (1984-86). YEAR No. Loggerheads No. Greens No. Leatherbacks 1984 218 0 1 1985 153 2 1 1986 149 0 1 TOTAL 520 2 3 Nesting activity on Delray Beach was not uniform but tended to be concentrated on the southern sections of the beach (Figure 5). As in the case of the previous seasons, nesting density was lowest in the center sections fo the public beach. A total of 11,323 eggs were excavated from 106 nests and were translocated to the artifical hatchery. The mean nest size for this sample was, 197 eggs. The range for this sample was 52 eggs for the smallest nest and 151 eggs for the largest nest. The mean, range and 200. Cl) 175 150 125 LL 100 0 CC 75 W M 50 Z 25 0 MAY JUNE JULY AUGUST MONTH Figure 4: Comparion of the monthly Sea Turtle crawl activity on lray Pr the De oject area during the 1986 nesting season. DELRAY SEA TURTLE MONITORING STUDY xll@ 0 cot A AN 7-1C OCiEAN NESTS FALSE CRAWLS 100 80 Cc 60 1 w I z 40 U= L 20 v ol P P p p p p p 27-28 25- 24 23-24 2 1-22 io-20 17-18 15-16 13-14 11-12 9-10 7-6 5-4 3-4 1-2 all I 1 1114111. 1,000 FEET NESTING ZONES FI(3-4: CRAWL DENSITIES COMPARED OVER 1.000' SECTIONS OF BEACH incubation time for the past three seasons is presented in,table 4. Table 4: Mean nest size, range of nest size and mean incubation time compared over the last three seasons (1984-86). Year Mean Nest Size Smallest Nest Largest Nest Mean Incubation Time (Days) 1984 114 49 160 54 1985 109 60 158 53 1986 108 52 151 53 A comparison between the hatching success of the natural nest sample and the artifical hatchery nest sample is similar. This suggest that the nests which were excavated were not signifcantly impacted. The hatching success for the natural nests was 78.4% and the hatching success for the artificial hatchery nests was 80.4%. Last season the hatching success for the natural nests was 77.5% and 74.6% for the artificiallyl incubated nests. S xxrnrnza -v -y The 1986 Delray Sea Turtle program consisted of two parts--nest relocation and public education. The 1986 season lasted 107 days. During this time 150 nests were observed on the public beach. All but one nest were made by loggerhead sea turtles. The exception was a leatherback sea turtle. A total of 106 of these nests were removed to the hatchery. From these nests a totalof 9,100 hatchlings were released into the sea. The hatching success percentage for the hatchery nests was similar to the natural nests. This indicated that the relocation program was successful. A regression analysis comparing the nesting activity over the last three seasons on Delray Beach suggests a slight decrease in activity. However, based on confidence level value, thi!§ trend was not considered to be highly signifcant. Because of the many human disturbances impacting sea turtle nesting observed during the past three seasons, both investigators reccommend that this program be continued. 'Now incubation time for the past three seasons is presented in table 4. Table 4: Mean nest size, range of nest size and mean incubation time compared over the last three seasons (1984-86). Year Mean Nest Size Smallest Nest Largest Nest Mean Incubation Time (Days) 1984 114 49 160 54 1985 109 60 158 53 1986 108 52 151 53 A comparison between the hatching success of the natural nest sample and the artifical hatchery nest sample is similar. This suggest that the nests which were excavated were not signifcantly impacted. The hatching success for the natural nests was 78.4% and the hatching success for the artificial hatchery nests was 80.4%. Last season the hatching success for the natural nests was 77.5% and 74.6% for the artificiallyi incubated nests. S txrnxna -if- y The 1986 Delray Sea Turtle program consisted of two parts--nest relocation and public education. The 1986 season lasted 107 days. During this time 150 nests were observed on the public beach. All but one nest were made by loggerhead sea turtles. The exception was a leatherback sea turtle. A total of 106 of these nests were removed to the hatchery. From these nests a totalof 9,100 hatchlings were released into the sea. @f 0 ;1112101MR, 3 6668 14102 8177