Some Aspects of the Nesting Behavior and Reproductive Biology of Sea Turtles 1

Transcription

1 AMER. ZOOL., 20: (1980) Sme Aspects f the Nesting Behavir and Reprductive Bilgy f Sea Turtles 1 HAROLD F. HIRTH Department f Bilgy, University f Utah, Salt Lake City, Utah SYNOPSIS. Basic reprductive data frm 21 green turtle (Chelnia mydas), 8 leatherback (Dermchelys criacea), 7 hawksbill (Eretmchelys imbricata), 7 live ridley (Lepidchelys livacea), 6 lggerhead (Caretta caretta), 1 Kemp's ridley (Lepidchelys kempt), and 1 flatback (Chelnia depressa) ppulatins are prvided. Sme intraspecific and interspecific relatinships between size f nester and clutch, egg size and hatchling size are analyzed. Measurements f reprductive rates ( = numbers f hatchlings per female per year) in 1 1 ppulatins varied frm 35 t 200 in an live ridley and lggerhead clny, respectively. Nesting behavir f each species is described in terms f type f nesting emergence and time spent n the nesting beach (=chelnery). The relatively large number f ylkless eggs laid by many leatherbacks and by sme hawksbills invites further study. Sme aspects f sea turtle nesting behavir and reprductin are cmpared t thse f ther chelnians. INTRODUCTION Currently there is a surge f interest in the life-histry strategies f marine turtles. Much f this interest revlves arund an increased awareness that sme ppulatins are endangered and that sme species are ecnmically valuable. Althugh sme aspects f a sea turtle's life histry, such as grwth rate and lngevity, are almst cmpletely unknwn, ther aspects like fecundity and nesting behavir, which are easily mnitred by land-based bilgists, are well dcumented. The main purpses f this paper are t review sme f the distinctive aspects f the reprductive bilgy and nesting behavir f sea turtles, t pint ut relatinships between bdy size and reprductive parameters, and t prvide estimates f reprductive rates in sme f the better-knwn ppulatins. The carapace length f a sea turtle is the maximum straight-line distance alng the midline, frm the anterir-mst margin f the cervical scute t the psterir-mst edge f the marginal scale. Investigatrs shuld clearly state the methd they use t measure the carapace length f leatherbacks. In the few studies cited herein 1 Frm the Sympsium n Behaviral and Reprductive Bilgy f Sea Turtles presented at the Annual Meeting f the American Sciety f Zlgists, December 1979, at Tampa, Flrida. 507 where length f the carapace ver the curve is recrded, I have, fr cmparative purpses, subtracted 4 cm frm the measurements (2 cm in case f Chelnia depressa). Exact cnversins wuld, f curse, depend upn the arch f the shells but my reductin hpefully brings ver-the-curve measurements mre in line with the cnventinal methd f measuring sea turtles. Where several studies have been cnducted n the same nesting beach by different investigatrs, I have used demgraphic data frm the mst cmprehensive study, particularly the study with the largest sample sizes. Als, where pssible, I have used carapace length measurements that I have taken since this eliminates sme f the human variatin in taking this measurement. I use the wrd chelnery (pi. chelneries) t refer t the nesting beach f a sea turtle. The level f nesting n sme chelneries mentined in this paper may nw nt be f any majr significance. Data frm such nesting beaches are included fr cmparative purpses. I use established specific names nly (the taxnmy f sea turtles, especially at the specific and subspecific levels, is currently underging revisin). The means used in regressins were frm samples f five r mre. Statistical significance is at the 5% level and statistical prcedure fllws Skal and Rhlf (1969).

2 TABLE 1. Reprductive bilgy f green turtles. 3 O 00 Lcality Trtuguer, Csta Rica b She!! beach, Guyana 11 Surinam 11 Aves Is. Ascensin Is. Eurpa Is. Trmelin Is. Aldabra Atll Carapace length f nesting females (cm) Sharma beach, 96 Suth Yemen 1 " ( ) Hawke's Bay, Pakistan 11 K Kram Is., Thailand Pangumbahan, Indnesia ( ) ( ) 109 (97-125) ( ) ( ) (91-125) ( ) ( ) (75-105) Nesting seasn July-Sept March-Aug Peak July Feb-July Peak Apr-May Mar-Sept Peak June-Aug Jan-June Peak Feb-Apr Peak Oct-Feb Peak Oct-Dec Peak Feb-Oct Peak Oct-Nv Peak June-Nv Peak Apr-Sept Peak June-Nv Diameter f eggs (mm) 45.7 ( ) ca (40-50) 44.4 ( ) 54.6 (49-58) 44.7 ( ) 44.6 ( ) ( ) (50-55) 45 Weight f e gg s <g) 45.1 ( ) 47.9 ( ) 48 ( ) 44.8 (35-55) Clutch 110 (18-193) ( ) 138 (12-226) (53-181) 147 (75-238) (79-230) 90? 106 (70-130) (70-130) 107 Carapace Renesting Length f length f interval incubatin hatcnlings (days) (days) (mm) (11-16) 14.5 (10-17) 12 (10-15) (13-15) 9.6 (7-13) 55.6 (48-70) 56.4 (49-65) 59.5 (58-62) (50-90) (47-69) ca. 48 (45-50) 50.6 (49-52) 49.7 (46-56) 51 (48-53) 54.6 ( ) 51.7 ( ) 50.9 (35-54) 48.6 ( ) 50.1 (45-53) 46.9 ( ) (48-53) Weight f hatcnlings (g) 27 ( ) 26 (21-31) 23.9 ( ) ca (20-28) Surce Carr and Hirth, 1962; Carr etal., 1978 Pritchard, 1969 Schulz, 1975 Rainey, 1971 Carr and Hirth, 1962; Carr etal., 1974; Carr, 1975 Servan, 1976; Hughes, 1974 Hughes, 1974 Hirth and Carr, 1970; Frazier, 1971; Gibsn, 1979 Hirth and Carr, 1970; F.A.O., 1973 Mintn, 1966 Penyapl, 1958 Suwel and Kuntjr, 1969; Suwel, 1971 ID

3 Lcality Pulau Berhala, Indnesia Sarawak Is. Sabah Is. Bnin Is. Hern Is. French Frigate Shals Scilly Atll Galapags Is. Naranj Beach, Csta Rica" Carapace length r nesting females (cm) 97.5 (84-110) (86-121) 92.2 ( ) 95.6 (80-109) 81.3 ( ) 82.9 (73-97) Nesting seasn Peak Nv Jan Peak July Aug Peak July-Oct May-Aug Nv Apr Peak Dec-Jan May Sept Peak June July Nv-May Peak Jan-Mar Diameter f eggs (mm) (43-46) " Mean values are fllwed by ranges in parentheses. b Mainland nesting beaches. TABLE 1. Cntinued. Weight f e gg s (g) 36 ( ) ( ) 50 (45-54) 118 (48-175) (3-184) (3-190) (70-150) 110 (50-200) 104 (38-145) 81 (19-131) 87 (65-107) Carapace Renesting Length f length f interval incubatin hatcnhngs (days) (days) (mm) 10.5 (8-17) 10.5 (2-19) 14.5 (9-21) 13 (11-18) 12.5 (54-70) (49-73) ca (42-77) 64.5 (54-88) 49 (46-51) 32? ca (48-59) 46.2 ( ) 51.2 (50-52) Weight f hatcnhngs 21.2 ( ) 22.1 ( ) ca (25-35) Surce Mhr, 1927 Harrissn, 1955; Hendricksn, 1958 de Silva, 1970 Fukada, 1965 Bustard, 1972 Balazs, 1979 Dumenge, 1973 Pritchard, 1971a Crnelius, 1976 z P! 1 z CO 5 < 1) PI H c PI

4 510 HAROLD F. HIRTH As C_ O 110 z Na, ;»Ga As. I MEAN CARAPACE LENGTH NESTING FEMALES (CM) FIG. 1. Mean clutch and mean shell length f nesting green turtles. Line is regressin f clutch (Y) n carapace length (): Y = , t (9) = 6.49, P< Data frm Table 1. Ga = Galapags, Na = Naranj, Ha = Hawaii, Sh = Sharma, Sa = Sarawak, T = Trtuguer, He = Hern, As = Ascensin, Tr = Trmelin, Su = Surinam, Eu = Eurpa. GREEN TURTLE, CHEWNIA MYDAS Sme basic reprductive data frm 21 green turtle ppulatins are given in Table 1. The average clutch and mean carapace length f nesting females frm 11 lcalities were used as data pints in a linear regressin (Fig. 1), and the evidence indicates a highly significant relatinship. A weighted regressin yielded a similar regressin line. Several investigatrs have cmmented n the small size f the East Pacific green turtles. Caldwell (19626) speculated that the green turtle in the Gulf f Califrnia matured at a smaller size than the Atlantic frm; and Marquez and Di (1973) estimated that the Gulf f Califrnia turtles reached reprductive maturity at a carapace length f frm 55 t 65 cm. Hwever, it is imprtant t nte that the smallest nesting females recrded n the Galapa- I Ha Sh.Sa T. H.. i 1 I 1 I MEAN CARAPACE LENGTH NESTING FEMALES ICMI Tr. Av..Su Eu FIG. 2. Mean egg diameter and the average carapace length f nesting green turtles. Regressin f egg size n carapace length is nt significant (( (8) = 1.58, P > 0.1). Data frm Table 1. Av = Aves; ther abbreviatins as in Figure 1. gs and Naranj beaches were actually larger than the smallest nesters recrded at Trtuguer, and were nly a few centimeters shrter than the smallest gravid individuals measured at K Kram, Scilly and Sharma (Table 1). Fur wrkers have reprted a psitive crrelatin between size f nesting female and clutch within a nesting ppulatin: Hrnell (1927) n Aldabra Atll, Bustard (1972) n Hern Island, Simn and Parkes (1976) n Ascensin Island, and Balazs (1979) n French Frigate Shals. Such psitive crrelatins are evidence fr a strng selective advantage t attainment f a large size. In additin, Bustard (1972) fund that n Hern Island the average size f the egg remains similar despite changes in size f the mther. Hughes (1974), hwever, fund n crrelatin between size f female and clutch n Eurpa Island. In this regard, it is interesting t nte that Eurpa turtles have the largest average clutch. Intraspecifically, the available data indicate n evidence f relatinships between the mean size f eggs and the mean size f nesting females at ten lcalities (Fig. 2), nr between the mean carapace length f hatchlings and mean carapace length f

5 NESTING BIOLOGY OF SEA TURTLES O -^ I i 45.Ga.Na 1 Ha. 1 Sh. 1 T»* 1 1 A». As, Su Eu MEAN CARAPACE LENGTH NESTING FEMALES (CM) FIG. 3. Mean carapace length f hatchlings and the average carapace length f nesting green turtles. Regressin f hatchling length n length f nesters is nt significant (t (9) = 1.37, P > 0.2). Data frm Table 1. Al = Aldabra; ther abbreviatins as in Figures 1 and 2. nesting females at eleven lcalities (Fig. 3). I interpret these data t mean that there is selectin fr a green turtle egg with a diameter f abut 45 mm and fr a hatchling with a carapace length f abut 50 mm. In additin t the data assembled in Table 1 there are several ther brief accunts f hatchlings whse shells register arund 50 mm. Deraniyagala (1939) mentined that hatchlings in Sri Lanka had a carapace length f between 49 and 54 mm, and that ne specimen frm the Maldive Islands had a shell length f 49 mm. McKewn (1977) reprted that green turtle hatchlings in the Slmn Islands ranged in carapace length frm 45 t 52 mm (mean, 49). The average rati f hatchling weight t egg weight in eight ppulatins (Table 1) varies frm 41 t 62%, and indicates that green turtle hatchlings are prprtinately lighter than almst all ther nn-marine turtles (cf., tabular data in Ewert, 1979). Sufficient reprductive data are available frm tw mainland and tw island chelneries t allw us t speculate n sme aspects f reprductive success. Data in Table 2 indicate that the number f hatchlings prduced by a female each year varies frm 67 t 138. This measurement f reprductive rate is used mainly fr cmparative purpses. As the Table indicates, green turtles d nt regularly nest annually and furthermre, the prductin f, say, 100 hatchlings per year is nt the bilgical equivalent f 200 hatchlings every ther year. The emergence percentages cited in the Table are the best available estimates fr natural nests, and these percentages as well as ther estimates in the Table may change when mre data becme available. Of the fur ppulatins the Hawaiian females prduce the fewest hatchlings, and this t sme extent is attributed t the relatively large numbers f females which appear n the chelnery during the nesting seasn and vipsit nly nce r nt at all. These individuals accunt fr the lw average number (1.8) f clutches per seasn. Eclgical factrs which culd be related t the differences in hatchling utput include predatin rates in the sea, grwth rates, and juvenile mvements. The average incubatin time ( = time frm vipsitin t emergence f the majrity f hatchlings n the surface) n fur mainland beaches is 52.7 days and that n fur island chelneries is 60.8 days (see Table 1). In the eleven lcales where infrmatin is available (see Table 1), 70 days is the lngest incubatin perid recrded amng three mainland nesting ppulatins while fur f the island nesting ppulatins registered incubatin perids lnger than 70 days. Shrter incubatin perids n mainlands are perhaps adaptive and may reflect upn the thery that egg predatin by terrestrial vertebrates is higher there than n islands. Hwever, mre infrmatin is needed befre ne can make precise statements regarding mainland and island incubatin perids. The weather during the incubatin perid certainly affects the length f incubatin (and affects the climb f hatchlings t the surface). Hendricksn (1958), Bustard (1972), and Schulz (1975), amng thers, fund that incubatin perids were lnger under rainy cnditins than dry cnditins. The available data als suggest n significant difference between the average number f eggs laid n insular r

6 512 HAROLD F. HIRTH TABLE 2. Estimates f reprductive rates f sme sea turtles. Lcality Trtuguer Surinam Hern Is. French Frigate Shals Mn Reps Tnga land Trtuguer Cusin Is. Eilanti, Surinam "La Escbilla," Mexic Trengganu Mean clutch Predminant re- Percent Hatchhngs per Mean number migratin successclutches per interval ful hatch female nesting seasn (years) (=emerge) per year Chelnia mydas " Chelnia depressa 3 ca Caretta caretta Eretmchelys imbricata at least " Lepidchelys livacea Dermchelys cnacea ca Surce Carr and Hirth, 1962; Carr et ai, 1978 Schulz, 1975 Bustard, 1972 Balazs, 1979 Limpus, 1971, persnal cmmunicatin Hughes, 1974 Carr et al., 1966; Carr and Stancyk, 1975 Diamnd, 1976 Schulz, 1975 Marquez, et al., 1976 Balasingam and Png, 1972; Siw, n date a Carr and Hirth (1962) recrded 50.8% hatch in an egg hatchery and Bustard (1972) dcuments abut 25% increased hatch in natural nests. b 25% is added t the 46.7% hatching rate in transplanted eggs. mainland beaches. Analysis and ranking f such reprductive and eclgical parameters represent lucrative areas f research fr the evlutinary eclgist. Data in Table 1 indicate that there is nesting year-arund n the chelneries in the Indian Ocean and the East Indies regin (but with sme strng seasnal peaks), while turtles in the Caribbean, Suth Atlantic, and Pacific regins tend t be strnger seasnal nesters. This tendency persists n mst mainland and island chelneries in these regins. The peak f nesting at mst f the chelneries in the nrthern and suthern hemispheres is during the summer. FLATBACK TURTLE, CHEI.OSIA DEPRESSA The flatback turtle is restricted t Australian waters. The mean carapace length f nesting females n Crab Island and n Mn Reps (a mainland beach) are respectively, abut 85.5 cm (Bustard, 1972) and abut 90.3 cm (Limpus, 1971). Thus, the flatback is slightly larger than the East Pacific ppulatins f its cngener, C. mydas, but it lays significantly fewer eggs (cf., Tables 1 and 2). There is year-arund nesting n sme flatback beaches in nrthern Australia while n ther beaches the peak f nesting is usually in Nvember and December. Daytime nesting is cmmn n Crab Island (Bustard, 1972) and has been bserved n Mn Reps (Bustard et al., 1975) althugh ncturnal nesting is predminant n the latter beach. On Mn Reps the females lay eggs at abut 15-day intervals and incubatin is abut 53 days. The average egg is 52.1 mm in diameter (range ) and it weighs

7 NESTING BIOLOGY OF SEA TURTLES 513 II ill usin well 2 n U S m «in m c Oi 195 ^3 <u Idw 2CO 62) I Ol r^ 77, 19 Oi lart,.c u W S" i t CO 55; Oi well 2 O CM iri * m iri t Ol d Smil tt Q 1975 c n 3 be t CO CO O to^cm 1 0 t^ ^ Tj- "^ m «" - " «~ "j* "7 -"Tf~t^~ ""00""Ol""CM t t in t t^ i ^ C O T3 13 I 0 ^ «J «, 3 be 3-2" =2 c3 < a. Z t -tt O (M 00 M O t^- ~j" (O i CO "7 Ol 00^; OOQO O5Q0 i = E JSJ: 77.8 g (range ). The average hatchling has a carapace length f 61.2 mm (range ) and it weighs 43.6 g (range ) (data frm Limpus, 1971). It is ntewrthy that the average egg weight, hatchling weight, and hatchling length f depressa n Mn Reps are greater than thse reprted fr any mydas ppulatin (see Table 1). Because f their size flatback hatchlings n the Australian beaches escape sme f the crab and bird predatrs that can take the smaller green and lggerhead hatchlings (Limpus, 1971). Presumably, depressa's large size has similar survival value during the critical first few mnths in the sea. On the ther hand, the available data indicate that a typical flatback prduces fewer hatchlings than almst all ther sea turtles (Table 2). LOGGERHEAD TURTLE, CARETTA CARET Like thse f all ther sea turtles, the eggs f lggerheads are spherical and white. Data in Table 3 indicate that the average diameters f eggs frm fur ppulatins n the better-knwn chelneries are similar. Limpus (1973) recrded that the eggs n Mn Reps ranged frm 37.6 t 42.3 mm (mean, 40.1) and Bustard et al. (1975) reprted that the eggs n Hern Island averaged abut 40 mm in diameter. There is n relatinship between the diameter f eggs and clutch in the Mn Reps ppulatin (see raw data in Limpus, 1973). In this sample the mean egg diameter, in clutches varying frm 102 t 160 eggs, ranged nly frm 38.4 t 41 mm. The mean carapace lengths f hatchlings frm fur ppulatins are als very similar (Table 3). In additin t the data in Table 3, the average shell length f ten hatchlings frm the Slmn Islands registered 44.9 mm (range 43-46) (Carr, 1952), and the mean carapace length f 60 frm Sirahama, Japan, measured 45.8 mm (range 40-55) (Nishimura, 1967). The available data suggest n relatinship between the average clutch and the average carapace length f nesting females at six chelneries (Table 3). My data frm the Masirah Island nesting ppulatin indicate n relatinship between clutch and length f female (I (27) = 0.53, P > 0.5).

8 514 HAROLD F. HIRTH In this sample f 29, the carapace lengths ranged frm 82 t 107 cm and the clutches varied between 72 and 130 eggs. Caldwell etal. (19596) fund n crrelatin between size f nesting female and clutch in the Jekyll Island ppulatin. Hwever, Ehrhart (19796) discvered a psitive crrelatin between clutch and size f nester n Cape Kennedy. Kaufmann (1975) nted that at Buritaca a female's clutch size increases with her successive renestings during a nesting seasn, but n clear trend in clutch size is evident during renestings at Mn Reps (Limpus, 1973) nr n Cape Kennedy (Ehrhart, 1977). It wuld be wrthwhile t determine if there is any crrelatin between length f nester and her ttal egg prductin ver a nesting seasn. An estimate f the reprductive rate f lggerheads in Suth Africa is prvided in Table 2. The figure f 200 is the highest cmputed in this paper and it will be interesting t cmpare this figure with ther lggerhead ppulatins when infrmatin becmes available. If reprductive data frm the nesting ppulatin n Cape Rmain, Suth Carlina (Caldwell, 1959), and frm nesters n Jekyll and Cumberland Islands, Gergia (Caldwell et al., 1959a, Caldwell 1962a, Richardsn et al., 1976), are cmbined, then the estimated reprductive rate f lggerheads in these tw states is 185. HAWKSBILL TURTLE, ERETMOCHEL.YS 1MBRICATA The data indicate a highly significant relatinship between the average clutch (fertile eggs) and mean carapace length f nesting hawksbills frm six chelneries (Fig. 4). The available data als indicate that the females nesting n Seil Ada Kebir and Jabal Aziz are the smallest, lay the fewest fertile eggs, and that their eggs are very slightly larger than ther hawksbill eggs. It is ntewrthy that n Seil Ada Kebir the ttal number f eggs laid in 26 clutches averaged but an average f 27.4% f the eggs in each clutch were ylkless and either small r malfrmed, leaving a mean f 73.2 fertile eggs in each clutch (Hirth and Latif, 1980). Likewise, n Jabal Aziz, MEAr*J CLUTCH / / /ija I I I / /.Ar C. T./ %She I I I I I MEAN CARAPACE LENGTH NESTING FEMALES (CM) FIG. 4. Average clutch and the average shell length f nesting hawksbill turtles. Line is regressin f clutch (Y) n carapace length (): Y = , t (4) = 12.08, P < Data frm Table 4. Se = Seil Ada, Ja = Jabal Aziz, Ar = Arnavn, She = Shell Beach, T = Trtuguer, C = Cusin. the ttal number f eggs laid in five clutches averaged but each nest cntained frm 9 t 39% ylkless eggs, leaving an average clutch f 81.2 (Hirth and Carr, 1970). In bth ppulatins the vast majrity f the ylkless eggs were laid last. It is tempting t speculate that these are sacrificial eggs depsited t satiate terrestrial predatrs althugh, theretically, as already mentined, eggs depsited n islands are subject t less predatin, at least by terrestrial vertebrates, than thse laid n mainlands. Physilgical explanatins, including the pssibility that the barren va are the last f the seasn, are perhaps mre plausible. At Trtuguer it was nted that "a variable number f small ylkless eggs may be laid" (Carr et al., 1966), but there is n mre elabratin. Deraniyagala (1939) nted that the last tw eggs laid in a clutch f 115 in Sri Lanka were either diminutive r defrmed, while anther hawksbill there laid 138 nrmal eggs. In Guyana, Pritchard (1969) fund n abnrmal-sized eggs in seven clutches

9 NESTING BIOLOGY OF SEA TURTLES s CARAPACE LENGTH NESTING HAWKSBILL (CM) FIG. 5. Clutch and carapace length f 26 hawksbills n Seil Ada Kebir Island. Slid circles and slid regressin line (Y = , t (24) = 2.39, P < 0.05) prtray fertile eggs while white circles and dashed regressin line (Y = , ( (24) = 2.74, P < 0.02) represent ttal number f eggs. Clutch (Y) is regressed n carapace length (). but he did bserve ne female lay a cmplete clutch f small r defrmed eggs. The relatinship between the number f fertile eggs depsited and the carapace length f the hawksbill in the Seil Ada Kebir ppulatin is significant as is the relatinship between the ttal number f eggs depsited and the size f the female (see Fig. 5). The prductivity f such hawksbill ppulatins thus depends t a large extent n size-distributin, and the implicatins fr management f hawksbills are bvius. Data in Table 4 indicate that the carapace lengths f hatchlings are similar, ranging frm 39.1 t 45.9 mm. Schmidt (1916) briefly mentined that the carapace lengths f hawksbill hatchlings in the West Indies were abut 40 mm, and that egg diameters ranged frm 39 t 43 mm. Deraniyagala (1939) fund the carapace lengths f hatchlings in ne clutch in Sri Lanka measured between 39 and 42 mm and that the eggs in three clutches varied frm 35 t 38 mm in diameter. The available data indicate that the hawksbill is nt an annual nester anywhere. The evidence des suggest a triennial nesting cycle at Trtuguer (Carr and Stancyk, 1975). Estimates f the annual reprductive rates n tw beaches where the female nests in a slitary fashin are prvided in Table 2. Because f the paucity f field data frm these tw sites and because f the assumptins made, the estimates f 77 and 189 might best be cnsidered as representing the minimal and maximal number f hatchlings per year per slitary nesting female. A ntable difference between the Trtuguer and Cusin Island nesting ppulatins, in additin t ne being n the mainland and the ther n an island, is that nesting is ncturnal at Trtuguer and diurnal at Cusin Island. It is interesting t nte that the reprductive rates f hawksbill and green turtles n the Trtuguer chelnery are abut 77 and 78 hatchlings, respectively. The hawksbill is a reptile which exhibits a wide range f nesting behavir frm predminantly slitary nesting t nesting in large grups. Whether this flexibility is due t a natural behaviral plasticity r whether we are witnessing artifactual behavir due t centuries f sustained explitatin is unknwn. Hirth and Latif (1980) prvide a brief histrical accunt f the trtiseshell trade in the Red Sea and speculate that at ne time there must have been a great amunt f nesting there. At the present time abut six turtles can be seen nesting each night in March n Seil Ada Kebir Island and the same may be true n ther islands in the Suakin Archipelag. Nesting in small grups has als been reprted n Jabal Aziz Island. T my knwledge, the largest hawksbill ppulatins extant tday are in the Trres Strait where large grups f up t 100 turtles nest nightly n sme islands (Bustard, 1974). KEMP'S RIDLEY TURTLE, LEPIDOCHELYS KEMP I Almst all Kemp's ridleys nest n the Tamaulipas cast f Mexic and thus this species has the mst restricted breeding range f any marine turtle. Nesting takes place between April and July (peak, May

10 Lcality Trtuguer, Csta Rica Shell Beach, Guyana Seil Ada Kebir Island, Sudan Jabal Aziz Is., Suth Yemen Cusin Is., Seychelles Palau Is., Micrnesia Arnavn Is., Slmn Islands Carapace length f nesting females (cm) 83.1 ( ) 84.1 ( ) 66 ( ) 69.5 (63-72) 85.5 ( ) 80.5 (68-93) Nesting seasn May-Nv peak May-June July-Aug Feb-Apr Jan-Mar Aug-Mar Mar-Sep year arund peak May-Aug * Mean values are fllwed by ranges in parentheses. TABLE 4. Reprductive bilgy f hawksbill turtles.* Diameter f eggs (mm) 38 ( ) (36-40) 40 (37-42) 40.5 (38-45) (33-36) Clutch (53-206) 158 ( ) 73.2 (32-117) 81.2 (69-99) 182 ( ) (63-151) (75-250) Renesting interval (days) ca (13-28) Length f incubatin (days) 58.6 (52-74) 62 (56-79) (60-70) 64 (43-90) Carapace length f natchlings (mm) 42.4 ( ) Surinam ( ) Surce Carr and Stancyk, 1975; Carr et at., 1966 Pritchard, 1969 Hirth and Latif, 1980 Hirth and Carr, 1970 Diamnd, 1976 Fukada, 1965 McKewn, 1977 en > r- D

11 NESTING BIOLOGY OF SEA TURTLES 517 and June), during the daytime, and is in the frm f a mass emergence knwn by the Spanish term "arribada" ( = arrival). The mass nesting f adults and subsequent mass emergence f hatchlings serves in part as a predatr satiatin r swamping strategy, and as such is analgus t the reprductive strategy f many ther diverse frms f life such as sme cicadas and certain trpical fruit trees. The arribada is nw estimated t be cmpsed f abut 500 females, dwn frm an estimated 40,000 in Althugh n infrmatin is available n the nesting success during large arribadas, it is pssible that the number f hatchlings prduced n this beach in primal times may have been similar t the number f livacea hatchlings prduced n "La Escbilla" tday (see Table 2). Pritchard and Marquez (1973) reprt a crrelatin between arribadas and wind directin and velcity but Casas-Andreu (1978) fund arribadas were mre assciated with lunar cycles and with ambient temperatures. Chavez et al. (1967) and Pritchard and Marquez (1973 and persnal cmmunicatin) have prvided the fllwing reprductive data: The carapace length f the average nesting female is 64.6 cm (range ); the average clutch is 110 (range ); and the eggs range frm 35 t 44.5 mm in diameter (mean, 38.9) and weigh between 24 and 41 g (mean, 30). The available data indicate that kempi nests up t three times per seasn (average abut tw) at abut 20- t 28-day intervals; incubatin averages 54 days (range 50 70) and, like livacea, the majrity f individuals nest n either a ne r tw-year cycle. Hatchling carapace lengths and weights are respectively, mean 42.7 mm (range 38-46) and 16.4 g ( ). OLIVE RIDLEY TURTLE, LEPIDOCHELYS OUVACEA The available data suggest that the largest gravid livacea are fund in Surinam and that they lay the largest clutches. Hwever, the Surinam eggs are similar in size t ther live ridley eggs and, except fr the hatchlings frm India, Surinam hatchlings are similar in size t hatchlings elsewhere (Table 5). Additinal reprts f hatchling carapace lengths are as fllws: 6 frm Pakistan ranged frm 41.5 t 46 mm (Mintn, 1966); 39 frm Masirah Island ranged frm 37.5 t 45 mm, mean 41.9 (F.A.O., 1973); and 5 frm sutheast Africa measured between 42.9 and 44.6 mm (Hughes, 1974). The turtles nesting n the Pacific casts f Mexic and Csta Rica average the smallest, include the smallest recrded nesters, and have the smallest average clutch. Pritchard (1969) reprted that larger Hnduran ridleys laid mre eggs than smaller nes. Observatins indicate that renesting in many livacea is synchrnized t the arribadas rather than t a precise endgenus rhythm. The 17, 30, and 22, 45 days cited in Table 5 are actually intervals between arribadas during which mst f the turtles renested. Hwever, sme live ridleys nest in a slitary fashin r in small grups and their renesting intervals are shrter than thse individuals renesting in the synchrnized mass nestings. Arribadas in Surinam are crrelated with strng ffshre winds (Schulz, 1975) but n such crrelatin has been fund in Csta Rica (Hughes and Richard, 1974) nr at sme nesting sites in Mexic (Casas-Andreu, 1978). The largest knwn nesting aggregatins f L. livacea are n mainland beaches {e.g., in Mexic, Csta Rica, India). The estimated reprductive rates n tw mainland beaches under cnditins f a large arribada ("La Escbilla") and small arribada (Eilanti) are given in Table 2. A very large number f eggs n the Mexican beach are destryed by nesting females in the same r succeeding arribada and the resulting lw reprductive rate, in terms f ffspring prduced by a female, may be cmpensated fr by a hatchling's success in escaping shallw-water predatrs when large numbers f them enter the water at abut the same time. Hatching success reaches 80% under cntrlled cnditins at "La Escbilla," and this raises the interesting pint that a slitary nesting female culd

12 00 Lcality Eilanti Beach, Surinam Crmandel cast, India Sri Lanka Playa "La Escbilla," Mexic Hnduras cast Playa Nancite, Csta Rica Playa Naranj, Csta Rica Carapace length f nesting females (cm) 68.5 (63-75) 67 (59-71) 62.9 ( ) 66.6 ( ) 63.3 ( ) 65.2 ( ) Nesting seasn Apr-Aug peak June-July Jan-Mar Sep-Jan July-Dec peak Aug-Oct year arund peak Aug-Nv year arund peak Sep-Dec * Mean values are fllwed by ranges in parentheses. TABLE 5. Reprductive bilgy f live ridley turtles. 4 Diameter f eggs (mm) 40 (37-41) 40.5 (38^3) 38.8 ( ) 37.5 ( ) Clutch 116 (37-166) (94-140) (90-135) ca. 100 (72-132) (98-123) 105 (74-126) Renesting interval (days) 17,30 22,45 Length f incubatin (days) 55 (46-62) 55.2 (50-63) 50 (42-50) 48.5 Carapace length f hatchhngs (mm) ( ) 42.8 (40-46) 40.3 Surce Schulz, 1975 Valliappan and Whitaker, 1974 Deraniyagala, 1939 Marquez et al, 1976 Carr, 1952 Hughes and Richard, 1974 Crnelius, 1976 Q

13 Lcality Matina, Csta Rica Trinidad Is. Surinam Silebache, French Guiana Tngaland, Suth Africa Sri Lanka Trengganu, Malaysia Playa Naranj, Csta Rica Carapace length 01 nesting females (cm) ca. 152 ( ) ( ) ca. 157 ( ) ca. 156 ( ) ca. 147 ( ) 141 ( ) Nesting seasn Apr-July Mar-Aug Feb June May-Aug Oct-Feb May June May Sept Dec-May? * Mean values are fllwed by ranges in parentheses. TABLE 6. Reprductive bilgy f leatherback turtles.* Diameter f eggs (mm) 53.6 ( ) (52-65) 53 (50-57) 53.1 (50-54) 51 Clutch 80 (45-121) (65-130) 85 (5-128) 88.1 (51-112) (55-142) (90-130) ca (35-140) 65.6 Renesting interval (days) Length f incubatin (days) ca. 65 (51-74) ca. 65 (60-70) (62-72) (58-65) 56 (52-61) Carapace length f natchlings (mm) (56-60) 58.7 ( ) (58-60) 55 Surce Carr and Ogren, 1959 Pritchard, 1971A Pritchard, 1971 A; Schulz, 1975 Pritchard, 1971A Hughes, 1974 Deraniyagala, 1939 Balasingam and Png, 1972; Siw, n date Crnelius, 1976 z PS 32 0 S a H c 5 C/l

14 520 HAROLD F. HIRTH prduce many mre hatchlings n the beach than ne nesting in an arribada. Fr an annual nester n "La Escbilla" the estimated reprductive rate is abut 70 hatchlings, but this is still smewhat less than the reprductive rate f an annual nester in Surinam. Hughes and Richard (1974) estimated that nly 0.2% f 11.5 millin eggs laid during ne arribada in Csta Rica prduced hatchlings. They pstulated that a cnsiderable number f eggs are destryed by turtles digging up each ther's nests, that many eggs are ruined by sil rganisms, and that hatchlings are taken by a variety f predatrs. It shuld be mentined, hwever, that L. livacea may be the mst abundant sea turtle in the wrld tday. It is bvius that many mre reprductive and eclgical data are needed befre ne can fully cmprehend the reprductive strategy f the live ridley, r that f any marine turtle. It is interesting t nte that Charnv (persnal cmmunicatin) has bserved high egg destructin by late spawning females n sme Pacific salmn redds. LEATHERBACK TURTLE, DERMOCHELYS COR1ACEA The average leatherback nesting at Naranj is smaller and lays fewer eggs than its cunterparts elsewhere (Table 6). Hwever, the smallest nesting females have been recrded n Trinidad and Sri Lanka. The very limited infrmatin indicates that the eggs and hatchlings f Naranj leatherbacks are slightly smaller than thse f ther leatherbacks. Except fr the Naranj site, leatherback breeding is restricted t spring and summer mnths. The average number f fertile eggs laid by leatherbacks varies frm 66 t 104, with mst laying abut 85, and each clutch usually cntains an additinal 10 t 33% small, ylkless eggs. These ylkless eggs are usually laid tward the end f vipsitin. The reprductive rate f a leatherback at Trengganu is estimated at 58 hatchlings per year (Table 2). It is ntewrthy that female leatherbacks, like flatbacks, prduce fewer but larger eggs and hatchlings cmpared t mst ther sea turtles. SOME GENERAL COMPARISONS OF SEA TURTLE NESTING BEHAVIOR Sme mdal attributes f nesting behavir are prvided in Table 7. The species are listed in descending rder f adult female shell length. The average time spent n the beach fr nesting is the time frm when the turtle leaves the sea until she reenters it. Naturally, the time spent n land varies widely and is affected by such things as size and nesting experience f the turtle, reprductive readiness, width f the strand, cmpactness f the sand, and the density f nesters. The use f terms ther than slitary t describe nesting n the beach des nt necessarily imply a scial nature. The Table indicates that the three largest species typically nest at night and that their average sjurn n the beach ranges between 1.5 and 2.5 hr. Sme ppulatins f Chelnia depressa and Eretmchelys nest in the daytime while ther ppulatins nest at night. Accrding t Ehrenfeld (1979) mst nn-marine turtles nest by day. The tw smallest sea turtles cmmnly nest in arribadas and spend an hur r less n the beach. The 1.6 hr given fr hawksbills was cmputed fr individuals nesting in small grups at night. Chelnia mydas may nest in small r large grups n the better-knwn beaches tday but certainly nested in large grups n many beaches befre depredatin by man. In my pinin, the green turtle is the mst "particular" nester and this partly accunts fr her relatively lng time n the strand. Lggerheads cme ashre in large grups during the peak f the nesting seasn n Masirah Island, and the density f nesting there may be the highest in the wrld fr lggerheads (F.A.O., 1973). CONCLUSIONS In general, the reptilian literature indicates that fecundity is directly crrelated with bdy size, intraspecifically and interspecifically. The data presented herein suggest that the mean clutch and the average carapace length f females in a nesting ppulatin are directly related intraspecifically amng live ridley, hawksbill and green turtle ppulatins, but the avail-

15 NESTING BIOLOGY OF SEA TURTLES 521 TABLE 7. Sme characteristics f marine turtle nesting behavir n the better-knwn chelneries. Species Dermchelys criacea Chelnia mydas Caretta caretta Chelnia depressa Eretmchelys imbricata Lepidchelys hvacea Lepidchelys kempt Predminant time f nesting night night night day and night day and night night day able evidence indicates n such relatinship amng lggerhead ppulatins. Insufficient data preclude making statements abut the average size f nester and clutch amng flatback and amng leatherback ppulatins, althugh small leatherbacks in the East Pacific d lay fewer eggs per clutch than their cnspecifics elsewhere. The leatherback is the largest sea turtle, yet its average number f eggs per clutch is less than that f any ther species f sea turtle except the flatback. The sea turtle data suggest a reciprcal assciatin intergenerically between the average clutch and the mean diameter f eggs. And, excluding the flatback, the evidence indicates a psitive trend intergenerically between the average length f nesters and the average size f eggs (and hatchlings). Hatching (=emergence) success in natural nests f all species f sea turtles averages between abut 60 and 85%, except at chelneries where density-dependent nest destructin prevails. In virtually all ppulatins f sea turtles, the average carapace length f hatchlings is a few millimeters larger than the average diameter f the eggs. As a grup sea turtles lay far mre eggs per clutch than mst ther chelnians, and their eggs are larger than thse f mst ther turtles (cf., tables in Ewert, 1979, and Mll, 1979). Mst marine turtles, like many ther trpical and subtrpical chelnians, lay several clutches during the nesting seasn. The data indicate a tendency fr larger species f sea turtles t have shrter renesting intervals than smaller species; the average renesting interval in leatherbacks is abut 9.5 days and that in ridleys is up t 3 r 4 wk. Average time spent n land fr nesting (hr) Predminant type nesting small grups large grups small and large grups small grups slitary, small and large grups arribada arnbada In general, sea turtle eggs have shrter incubatin perids than thse f mst ther turtles. And, althugh annual reprductive cycles are cmmn fr sme Kemp's and sme live ridley turtles and have been reprted in ther species f marine turtles, mst sea turtles nest every 2 r 3 yr, and in this regard are different frm mst female chelnians which generally have annual cycles (Mll, 1979). R ecmmendatins Much mre demgraphic wrk is needed. It wuld be interesting t see if intrappulatin trends, based n large sample sizes and measures f variance, are cnsistent with sme f the interppulatin trends described herein. Many leatherbacks and sme hawksbills lay a significant number f small, ylkless eggs alng with their fertile eggs. Other sea turtles ccasinally depsit a few such eggs. This reprductive trait shuld be investigated. ACKNOWLEDGMENTS This paper is dedicated t Archie Carr, mentr and sage. I thank the fllwing scientists fr cnstructive cmments n the paper: Dennis Bramble, Ric Charnv, Jhn Legler, Frank Parkinsn and Jhn Endler (wh als advised n statistical prcedure). I als thank Dave Owens fr rganizing this imprtant sympsium and Rbert Truland f the Chelnia Institute fr financially aiding the cnference and facilitating publicatin f this cmplete manuscript. REFERENCES Balasingam, E. and T. Y. Png Preliminary bservatin n nesting returns f the leathery

16 522 HAROLD F. HIRTH turtle (Dermchelys cnacea Linn.) in Central eclgy and survival utlk f the hawksbill turtle. Bil. Cnserv. 8: Trengganu, Malaysia. Malay Nat. J. 25:6-9. Balazs, G. H Synpsis f bilgical data n Casas-Andreu, G Analisis de la anidacin de the green turtle in the Hawaiian Islands. Final las trtugas marinas del gener Lepidchelys en reprt t N.O.A.A., Natinal Marine Fisheries Mexic. An. Centr Cienc. Mar Limnl. Univ. Service (cntract N. 79-ABA-02422). Nal. Autn. Mexic 5: Bustard, R Sea turtles: Their natural histry Chavez, H., M. Cntreras, and T. P. E. Hernandez. and cnservatin. Taplinger Publ. C., New Aspects bilgics y prteccin de la trtuga lra, Lepidchelys kempt (Carman), en la csta Yrk. Bustard, R Barrier reef sea turtle ppulatins. In Prc. Secnd Int. Cral Reef Symp- 17:1-40. de Tamaulipas, Mexic. Inst. Nac. Inv. Bil. Pes. sium 1, pp Great Barrier Reef Cmmittee, Brisbane, Australia. at Playa Naranj, Csta Rica. Brenesia 8:1-27. Crnelius, S. E Marine turtle nesting activity Bustard, H. R., P. Greenham, and C. Limpus. Deraniyagala, P. E. P The tetrapd reptiles f Nesting behavir f lggerhead and flatback turtles in Queensland, Australia. Kninkl. mb Mus., Ceyln. Ceyln. Vl. 1, Testudinates and crcdilians. Cl- Nederl. Akad. Wetenschappen Amsterdam. de Silva, G. S Marine turtle cnservatin in Prc. Series C, 78, N. 2: Sabah. Ann. Rep. Res. Branch Frest Dept., Caldwell, D. K The lggerhead turtles f Frest Dept., Sabah, Malaysia 1970; 125- Cape Rmain, Suth Carlina. Bull. Fla. State 136. Mus. 4: Diamnd, A. W Breeding bilgy and cnservatin f hawksbill turtles, Eretmchelys imbri- Caldwell, D. K. 1962a. Cmments n the nesting behavir f Atlantic lggerhead sea turtles, based cata L., n Cusin Island, Seychelles. Bil. Cnserv. 9: primarily n tagging returns. Quart. J. Fla. Acad. Sci. 25: Dumenge, F Develpment f the "turtle Caldwell, D. K. 1962A. Sea turtles in Baja Califrnian prject" in French Plynesia. In Suth Pacific Island Fisheries Newsletter, N. 10, pp waters (with special reference t thse f the Gulf f Califrnia), and the descriptin f a new subspecies f nrtheastern Pacific green turtle. Ls Ehrenfeld, D. W Behavir assciated with Numea, New Calednia. Angeles Cunty Mus., Cntrib. Sci. N. 61:3-31. nesting. In M. Harless and H. Mrlck (eds.), Caldwell, D. K., F. H. Berry, A. Carr, and R. A. Ragtzkie. 1959a. Multiple and grup nesting by Wiley and Sns, New Yrk. Turtles: Perspectives and research, pp the Atlantic lggerhead turtle. Bull. Fla. State Ehrhart, L. M Threatened and endangered Mus. 4: species f the Kennedy Space Center. Semi-annual reprt t the Natinal Aernautics and Caldwell, D. K., A. Carr, and L. H. Ogren Nesting and migratin f the Atlantic lggerhead turtle. Bull. Fla. State Mus. 4: Center, Bimedical Office Cde: MD-B, pp Space Administratin, Jhn F. Kennedy Space Caldwell, D. K., A. Carr, and T. R. Hellier, Jr Natural histry ntes n the Atlantic lggerhead turtle, Caretta caretta caretta. Quart. J. species f the Kennedy Space Center. Semi-an- Ehrhart, L. M. 1979a. Threatened and endangered Fla. Acad. Sci. 18: nual reprt t the Natinal Aernautics and Carr, A Handbk f turtles. Crnell U. Press, Space Administratin, Jhn F. Kennedy Space Ithaca, New Yrk. Center, Bimedical Office Cde: MD-B, pp. 1- Carr, A The Ascensin Island green turtle 214. clny. Cpeia 1975: Ehrhart, L. M Analysis f reprductive Carr, A., M. H. Carr, and A. B. Meylan The characteristics f Caretta caretta in east-central eclgy and migratins f sea turtles, 7. The west Flrida. Amer. Zl. 19:955. (Abstr.) Caribbean green turtle clny. Bull. Amer. Mus. Ewert, M. A The embry and its egg: Develpment and natural histry. In M. Harless and Nat. Hist Carr, A. and H. Hirth The eclgy and migratins f sea turtles, 5. Cmparative features search, pp Wiley and Sns, New Yrk. H. Mrlck (eds.), Turtles: Perspectives and re- f islated green turtle clnies. Amer. Mus. F.A.O Reprt t the Gvernment f the Peple's Demcratic Republic f Yemen n marine Nvitates 2091:1-42. Carr, A., H. Hirth, and L. Ogren The eclgy turtle management, based n the wrk f H. F. and migratins f sea turtles, 6. The hawksbill Hirth and S. L. Hllingwrth, marine turtle bilgists. Rep. FAO/UNDP (TA), (3178). turtle in the Caribbean Sea. Amer. Mus. Nvitates 2248:1-29. Frazier, J Observatins n sea turtles at Aldabra Atll. Phil. Trans. Ryal Sc. Lndn B Carr, A. and L. Ogren The eclgy and migratins f sea turtles, 3. Dermchelys in Csta 260: Rica. Amer. Mus. Nvitates N. 1958:1-29. Fukada, H Breeding habits f sme Japanese Carr, A., P. Rss, and S. Carr Internesting behavir f the green turtle, Chelnia mydas, at a Univ. B 27: reptiles (critical review). Bull. Kyt Gakugei mid-cean breeding grund. Cpeia 1974:703- Gibsn, T. S. H Green turtle (Chelnia mydas 706. (L.)) nesting activity at Aldabra Atll. Phil. Trans. Carr, A. and S. Stancyk Observatins n the Ryal Sc. Lndn B 286:

17 NESTING BIOLOGY OF SEA TURTLES 523 Harrissn, T The edible turtle (Chelnia mydas) in Brne. 3. Yung turtles in captivity. Sarawak. Mus. J. 6: Hendricksn, J. R The green sea turtle, Chelnia mydas (Linn.), in Malaya and Sarawak. Prc. Zl. Sc. Lndn 130: Hirth, H. and A. Carr The green turtle in the Gulf f Aden and the Seychelles Islands. Verh. K. Ned. Akad. Wet. (Afd. Nat. Tweede Reeks) 58:1-44. Hirth, H. and E. M. A. Latif A nesting clny f the hawksbill turtle (Eretmchelys imbricata) n Seil Ada Kebir Island, Suakin Archipelag, Sudan. Bil. Cnserv. 17: Hrnell, J The turtle fisheries f the Seychelles Islands. Lndn: H.M.S.O. Hughes, D. A. and J. D. Richard The nesting f the Pacific ridley turtle Lepidchelys livacea n Playa Nancite, Csta Rica. Marine Bil. 24: Hughes, G. R The sea turtles f suth-east Africa. I. Status, mrphlgy and distributins. II. The bilgy f the Tngaland lggerhead turtle Caretta caretta L. with cmments n the leatherback turtle Dermchelys criacea L. and the green turtle Chelnia mydas L. in the study regin. Invest. Rep. Ns. 35, 36. Suth African Assc. Mar. Bil. Res. Oceangraphic Res. Institute, Durban, Suth Africa. Kaufmann, R Studies n the lggerhead sea turtle, Caretta caretta caretta (Linne) in Clmbia, Suth America. Herpetlgica 31: Limpus, C. J The flatback turtle Chelnia depressa Carman in sutheast Queensland, Australia. Herpetlgica 27: Limpus, C.J Lggerhead turtles (Caretta caretta) in Australia: Fd surces while nesting. Herpetlgica 29: Marquez, R. M. and T. Di Ensay teric sbre el analisis de la pblacin de trtuga prieta, Chelnia mydas camnegra Caldwell, en aguas del Glf de Califrnia, Mexic. Bull. Tkai Reg. Fish. Res. Lab. N. 73:1-22. Marquez, R. M., A. Villanueva O., and C. Pentaflres S Sinpsis de dats bilgics sbre la trtuga glfina, Lepidchelys livacea (Eschschltz, 1829). McKewn, A Marine turtles f the Slmn Islands. Ministry f Natural Resurces, Fisheries Divisin, Hniara. Mintn, S. A A cntributin t the herpetlgy f West Pakistan. Bull. Araer. Mus. Nat. Hist. 134: Mhr, J. C. van der Meer On anmalus eggs f the green turtle. Misc. Zl. Sumatrana 22:1-2. Mll, E. O Reprductive cycles and adaptatins. In M. Harless and H. Mrlck (eds.), Turtles: Perspectives and research, pp Wiley and Sns, New Yrk. Nishimura, S The lggerhead turtles in Japan and neighbring waters (Testudinata: Chelniidae). Publ. Set Mar. Bil. Lab. 15: Penyapl, A A preliminary study f the sea turtles in the Gulf f Thailand. Nat. Hist. Bull. Siam Sc. 17: Pritchard, P. C. H Sea turtles f the Guianas. Bull. Fla. State Mus. 13: Pritchard, P. C. H. 1971a. Galapags sea turtles preliminary findings. J. Herp. 5:1-9. Pritchard, P. C. H. 1971A. The leatherback r leathery turtle, Dermchelys criacea. I.U.C.N. Mngraph N. 1, Mrges, Switzerland, 39 pp. Pritchard, P. C. H. and R. Marquez Kemp's ridley turtle r Atlantic ridley. I.U.C.N. Mngraph N. 2, Mrges, Switzerland, 30 pp. Rainey, W. E Recnnaissance f the green turtle, Chelnia mydas, nesting aggregatin at Aves Island, Lesser Antilles. Caribbean Res. Inst., Cllege f Virgin Islands, St. Thmas, V.I. Richardsn, T. H., J. I. Richardsn, C. Ruckdeschel, and M. W. Dix Remigratin patterns f lggerhead sea turtles (Caretta caretta) nesting n Little Cumberland and Cumberland Islands, Gergia. In Prceedings f the Flrida and Interreginal Cnference n Sea Turtles, July, 1976, Jensen Beach, Flrida, pp Fla. Mar. Res. Publ. N. 33. Schmidt, J Marking experiments with turtles in the Danish West Indies. Med. Kmm. Havund., Ser. Fiskeri 5:1-26. Schulz, J. P Sea turtles nesting in Surinam. Neder. Cmm. Int. Natuur. Med. 23, Stichting Natuur. Suriname (Stinasu), Verhandeling N. 3. Servan, J Eclgie de la trtue vena a Pile Eurpa (Canal de Mzambique). Terre Vie 30: Simn, M. H. and A. S. Parkes The green sea turtle (Chelnia mydas): Nesting n Ascensin Island, J. Zl., Lndn 179: Siw, K. T. N date. Leathery (Dermchelys criacea) cnservatin prgramme in Rantau Abang, the State f Trengganu, Malaysia. Mime. reprt, Fisheries Dept., Trengganu, Malaysia. Skal, R. R. and F. J. Rhlf Bimetry. W. H. Freeman C., San Francisc. Suwel, I. S Sea turtles in Indnesia. In Marine turtles, pp I.U.C.N. Publ. New Series, 31. Mrges, Switzerland. Suwel, I. S. and Kuntjr Penju Laut. Rimba Indnesia 14: Valliappan, S. and R. Whitaker Olive ridleys n the Crmandel cast. Madras Snake Park, Madras, India. Wrth, D. F. and J. B. Smith Marine turtle nesting n Hutchinsn Island, Flrida, in Flrida Marine Res. Publ. 18:1-17.

18