Seasonal Variation in Clutch Size of the Turtle, Dermochelys coriacea

Tucker, Anton D.; Frazer, Nat B.

doi:10.2307/1564689

Cited by 11 publications

(10 citation statements)

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“…In Puerto Rico, the mean number of eggs in leatherback clutches diminishes as the season progresses (Tucker and Frazer 1994). So, in Suriname it is possible that in the warmer last part of the nesting season, a clutch of 100% females produces fewer hatchlings in total than a clutch containing males that was laid in the cooler earlier part of the season.…”

Section: Discussionmentioning

confidence: 99%

Estimating past and present sex ratios of sea turtles in Suriname

Godfrey¹,

Barreto²,

Mrosovsky³

1996

Can. J. Zool.

121

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Leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles in Suriname lay eggs over several months of the year. During this nesting season, changes in rainfall produce changes in sand temperature, which in turn influence the sexual differentiation of incubating sea turtle embryos. The overall sex ratio of leatherback and green sea turtle hatchlings produced at Matapica beach in Suriname was investigated. Estimates of the sex ratios of these turtles in 1993 (green turtles 63.8 % female, leatherbacks 69.4 % female) were roughly 10 % more female-biased than those from an earlier study in 1982. For both species, a significant negative relationship was found between monthly rainfall and monthly sex ratios. Using this relationship and data on rainfall in the past, it was possible to estimate overall sex ratios for an additional 12 years. These estimates varied considerably among different years, ranging from 20 to 90% female in the case of green turtles. Nevertheless, males tended to be produced primarily in April and May, while some females were produced in all months. Such seasonal patterns of production of turtles of different sexes have implications for sea turtle conservation programs that involve manipulating or harvesting eggs.RCsumC : Les tortues marines Dermochelys coriacea et Chelonia mydas pondent leurs oeufs pendant plusieurs mois au Suriname. Durant cette saison de nidification, les variations des prCcipitations entrainent des changements dans la tempkrature du sable, ce qui influence la diffkrenciation sexuelle des embryons en incubation. Les rapports miles : femelles des tortues donates des deux espkces ont Ct C dCterminCs ii Matapica Beach au Suriname. L'estimation de ces rapports en 1993 (63,8% de femelles chez C. mydas et 69,4% de femelles chez D. coriacea) a rCvClC que les Cclosions ont donnC environ 10% de plus de femelles au cours de cette annCe qu'au cours d'une Ctude antCrieure menCe en 1982. Chez les deux espkces, il existe une relation nCgative significative entre les prCcipitations mensuelles et les rapports miles : femelles mensuels. A partir de cette relation et des donnCes sur les prCcipitations dans le passC, il a Ct C possible de faire une estimation des rapports miles : femelles globaux au cours de 12 annCes supplCmentaires. Ces estimations varient fortement d'une annCe ii l'autre, allant de 20 ii 90% de femelles chez C. mydas. NCanmoins, les miles Ctaient plut6t produits en avril ou en mai alors que quelques femelles Ctaient produites tous les mois. De telles variations dans la production des tortues des deux sexes doivent entrer en ligne de compte dans les programmes de conservation des tortues marines dont le protocole comporte des opdrations de manipulation ou de rCcolte d'oeufs.[Traduit par la RCdaction]

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Section: Discussionmentioning

confidence: 99%

Estimating past and present sex ratios of sea turtles in Suriname

Godfrey¹,

Barreto²,

Mrosovsky³

1996

Can. J. Zool.

121

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show abstract

“…The facts that many individuals went on to nest more than five times and that not all individuals laid the same number of clutches may have obscured any trend that was present. Tucker and Frazer (1994) showed that leatherback clutch size decreased after the fifth nesting event at the population level, regardless of female clutch frequency. It is possible that a similar trend would be seen at the individual level if later nests were considered.…”

Section: Reproductive Outputmentioning

confidence: 94%

“…It is possible that a similar trend would be seen at the individual level if later nests were considered. In addition, it is thought that such trends may vary within a population and even within individuals among nesting seasons (Tucker and Frazer, 1994).…”

Section: Reproductive Outputmentioning

confidence: 99%

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Changes in Plasma Chemistry and Reproductive Output of Nesting Leatherbacks

Honarvar

Brodsky²,

Fitzgerald

et al. 2011

Herpetologica

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“…This pattern is not previously known in turtles (but see seasonal decrease in clutch size reviewed in Tucker & Frazer, 1994). Seasonal changes in clutch and egg size occur in some lizards (reviewed in Nussbaum, 1981) and have been reported for other animals (e.g.…”

Section: Seasonal Changes In Clutch Size and Egg Sizementioning

confidence: 87%

Twice every second year: reproduction in the pig‐nosed turtle, Carettochelys insculpta, in the wet–dry tropics of Australia

2003

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The reproductive biology of female pig-nosed turtles Carettochelys insculpta was studied for 4 years in the wetdry tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the dry season diet (aquatic vegetation). Life-history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with 'big' and 'small' wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life-history theory suggest that a big wet season is a time of high energy accumulation for the turtles.

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Seasonal Variation in Clutch Size of the Turtle, Dermochelys coriacea

Cited by 11 publications

References 0 publications

Estimating past and present sex ratios of sea turtles in Suriname

Estimating past and present sex ratios of sea turtles in Suriname

Changes in Plasma Chemistry and Reproductive Output of Nesting Leatherbacks

Twice every second year: reproduction in the pig‐nosed turtle, Carettochelys insculpta, in the wet–dry tropics of Australia

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