Ecology of loggerhead marine turtles Caretta caretta in a neritic foraging habitat: movements, sex ratios and growth rates

Mortality patterns of marine turtles entangled in fishing gear, found dead at sea or stranded dead on and around the coast of Britain in the period 1992–1996 are described. Of a total of 38 dead turtles identified, 35 were leatherback turtles (Dermochelys coriacea) and three were loggerhead turtles (Caretta caretta). All D. coriacea were considered adults or subadults nearing sexual maturity. Six individuals were assessed as females, ten were classified as males and 19 were not sexed. Dermochelys coriacea (N=20 measured) ranged from 120 to 210 cm in curved carapace length (mean, 152 cm). The three C. caretta were juveniles, and ranged from 15 to 30 cm curved carapace length. Possible origins, causes of mortality and interactions with fisheries are discussed. In addition, contaminant levels were determined in the tissues of three D. coriacea. Concentrations of organic contaminants determined were found to be low.

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Comparative Growth Rates of Wild Immature Chelonia mydas and Caretta caretta in Florida

Journal of Herpetology ◽

10.2307/1563536 ◽

1981 ◽

Vol 15 (4) ◽

pp. 447 ◽

Cited By ~ 28

Author(s):

Mary T. Mendonca

Keyword(s):

Growth Rates ◽

Chelonia Mydas ◽

Caretta Caretta

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Validation of incubation duration as an index of the sex ratio of hatchling sea turtles

Canadian Journal of Zoology ◽

10.1139/z99-039 ◽

1999 ◽

Vol 77 (5) ◽

pp. 831-835 ◽

Cited By ~ 40

Author(s):

N Mrosovsky ◽

Cecília Baptistotte ◽

Matthew H Godfrey

Keyword(s):

Sex Ratio ◽

High Temperatures ◽

Low Temperatures ◽

Sea Turtles ◽

Sex Ratios ◽

Caretta Caretta ◽

Turtle Species ◽

Loggerhead Turtles ◽

Incubation Duration

One method of estimating the sex ratio of hatchling sea turtles is to use the incubation duration. Long and short durations imply low and high temperatures, respectively. In turtle species whose sex is determined by temperature, males are produced at low temperatures and females at high temperatures. This study assesses the validity of using incubation duration to estimate the sex ratio. Samples of hatchling loggerhead turtles (Caretta caretta) were collected from nests with known incubation durations, and sex was ascertained by means of histology. The sex ratio of groups of nests determined by histology was compared with that predicted from previous relationships between incubation duration and sex ratio. For conditions causing relatively long or relatively short incubation durations, the sex ratio could be predicted with considerable accuracy. For conditions causing durations nearer to the pivotal duration (that which gives 50% of each sex), predictions could be off by 10%, depending on the distribution of incubation durations, but it was still possible to determine whether ratios were highly skewed or approximately balanced. Estimating sex ratios of hatchling sea turtles from incubation durations is simple, cheap, and can be used retrospectively.

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Growth rates of wild green turtles,Chelonia mydas, at a temperate foraging habitat in the northern Gulf of Mexico: assessing short‐term effects of cold‐stunning on growth

Journal of Natural History ◽

10.1080/00222930802357335 ◽

2008 ◽

Vol 42 (43-44) ◽

pp. 2793-2807 ◽

Cited By ~ 16

Author(s):

Erin McMichael ◽

Jeffrey Seminoff ◽

Raymond Carthy

Keyword(s):

Gulf Of Mexico ◽

Growth Rates ◽

Chelonia Mydas ◽

Foraging Habitat ◽

Short Term ◽

Northern Gulf Of Mexico ◽

Green Turtles ◽

Short Term Effects

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Reconstructed paternal genotypes reveal variable rates of multiple paternity at three rookeries of loggerhead sea turtles (Caretta caretta) in Western Australia

Australian Journal of Zoology ◽

10.1071/zo14076 ◽

2014 ◽

Vol 62 (6) ◽

pp. 454 ◽

Cited By ~ 16

Author(s):

J. N. Tedeschi ◽

N. J. Mitchell ◽

O. Berry ◽

S. Whiting ◽

M. Meekan ◽

...

Keyword(s):

Population Size ◽

Western Australia ◽

Sea Turtles ◽

Sex Ratios ◽

Multiple Paternity ◽

Caretta Caretta ◽

Loggerhead Sea Turtles ◽

Female Population ◽

Species Specific ◽

Operational Sex Ratios

Female sea turtles are promiscuous, with clutches of eggs often sired by multiple males and rates of multiple paternity varying greatly within and across species. We investigated levels of multiple paternity in loggerhead sea turtles (Caretta caretta) from three rookeries in Western Australia by analysing polymorphic species-specific genetic markers. We predicted that the level of multiple paternity would be related to female population size and hence the large rookery at Dirk Hartog Island would have higher rates of multiple paternity than two smaller mainland rookeries at Gnaraloo Bay and Bungelup Beach. Contrary to our prediction, we found highly variable rates of multiple paternity among the rookeries that we sampled, which was unrelated to female population size (25% at Bungelup Beach, 86% at Gnaraloo Bay, and 36% at Dirk Hartog Island). Approximately 45 different males sired 25 clutches and the average number of sires per clutch ranged from 1.2 to 2.1, depending on the rookery sampled. The variance in rates of multiple paternity among rookeries suggests that operational sex ratios are variable in Western Australia. Periodic monitoring would show whether the observed patterns of multiple paternity for these three rookeries are stable over time, and our data provide a baseline for detecting shifts in operational sex ratios.

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