The green turtle, Chelonia mydas, in Queensland: breeding males in the southern Great Barrier Reef

1993 ◽  
Vol 20 (4) ◽  
pp. 513 ◽  
Author(s):  
CJ Limpus
Keyword(s):  
Great Barrier Reef ◽  
Green Turtle ◽  
Carapace Length ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Adult Males ◽  
Green Turtles ◽  
Adult Females ◽  
Breeding Seasons ◽  
Slow Growing

Breeding male green turtles, Chelonia mydas, at any one courtship area in the southern Great Barrier Reef mate with females that will nest on rookeries spread throughout the region. In comparison with the breeding females from the same breeding unit, the males are smaller in curved carapace length, and a higher proportion of males remigrate for additional breeding seasons at 1-2-year intervals. Like the adult females, adult males are slow-growing, averaging 0.046 cm year-1. Each male appears to display a fidelity to a particular courtship area, to which it returns in successive breeding migrations. At the conclusion of the courtship period, the males disperse to widely scattered feeding areas.

scholarly journals Closing the gap: mixed stock analysis of three foraging populations of green turtles (Chelonia mydas) on the Great Barrier Reef

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5651
Author(s):  
Karina Jones ◽  
Michael Jensen ◽  
Graham Burgess ◽  
Johanna Leonhardt ◽  
Lynne van Herwerden ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Spatial Ecology ◽  
New Caledonia ◽  
Relative Proportion ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Green Turtles ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock

A solid understanding of the spatial ecology of green turtles (Chelonia mydas) is fundamental to their effective conservation. Yet this species, like many marine migratory species, is challenging to monitor and manage because they utilise a variety of habitats that span wide spatio-temporal scales. To further elucidate the connectivity between green turtle rookeries and foraging populations, we sequenced the mtDNA control region of 278 turtles across three foraging sites from the northern Great Barrier Reef (GBR) spanning more than 330 km: Cockle Bay, Green Island and Low Isles. This was performed with a newly developed assay, which targets a longer fragment of mtDNA than previous studies. We used a mixed stock analysis (MSA), which utilises genetic data to estimate the relative proportion of genetically distinct breeding populations found at a given foraging ground. Haplotype and nucleotide diversity was also assessed. A total of 35 haplotypes were identified across all sites, 13 of which had not been found previously in any rookery. The MSA showed that the northern GBR (nGBR), Coral Sea (CS), southern GBR (sGBR) and New Caledonia (NC) stocks supplied the bulk of the turtles at all three sites, with small contributions from other rookeries in the region. Stock contribution shifted gradually from north to south, although sGBR/CS stock dominated at all three sites. The major change in composition occured between Cockle Bay and Low Isles. Our findings, together with other recent studies in this field, show that stock composition shifts with latitude as a natural progression along a coastal gradient. This phenomenon is likely to be the result of ocean currents influencing both post-hatchling dispersal and subsequent juvenile recruitment to diverse coastal foraging sites.

Migration of green (Chelonia mydas) and loggerhead (caretta caretta) turtles to and from eastern Australian rookeries

1992 ◽  
Vol 19 (3) ◽  
pp. 347 ◽  
Author(s):  
CJ Limpus ◽  
JD Miller ◽  
CJ Paramenter ◽  
D Reimer ◽  
N McLachlan ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Indigenous People ◽  
Chelonia Mydas ◽  
Caretta Caretta ◽  
Commercial Fishing ◽  
High Fidelity ◽  
Barrier Reef ◽  
Migratory Behaviour ◽  
Green Turtles ◽  
Feeding Ground

Feeding-ground captures of green (Chelonia mydas) and loggerhead (Caretta caretta) turtles tagged while nesting at eastern Australian rookeries over a 21-year period are summarised. These turtles which nest in the Great Barrier Reef region range widely throughout the Arafura and Coral seas. The tag recoveries include many from turtles that live in neighbouring countries and migrate to breed in Australia. The breeding female shows a high fidelity to her home feeding ground as well as to her nesting beach. Most recaptures of the green turtles occurred during hunting for food by indigenous people while most recaptures of loggerhead turtles were incidental captures in commercial fishing activities. Migratory behaviour, imprinting and navigation are discussed.

scholarly journals Foraging Habits of Green Sea Turtles (Chelonia mydas) in the Northwestern Gulf of Mexico

2021 ◽  
Vol 8 ◽  
Author(s):  
Lyndsey N. Howell ◽  
Donna J. Shaver
Keyword(s):  
Gulf Of Mexico ◽  
Green Turtle ◽  
Carapace Length ◽  
Foraging Ecology ◽  
Chelonia Mydas ◽  
Foraging Habitat ◽  
Seagrass Meadows ◽  
Green Sea Turtles ◽  
Green Turtles

Knowledge of green turtle (Chelonia mydas) foraging ecology in the northwestern Gulf of Mexico (GOM) is critical as populations begin to recover from heavy harvesting in prior centuries. We present a comprehensive long-term assessment of green turtle diets from carcasses salvaged from 1987 to 2014 along the Texas coast. Digestive tract contents were examined from 420 green turtles, ranging in size from 7.3 to 86.0 cm in straight carapace length (SCLmax). Green turtles as small as 16.2 cm SCLmax recruit from the oceanic environment to nearshore foraging habitat in the northwestern GOM and consume macroalgae principally. A successive shift in diet and habitat to inshore seagrasses was evident by the seagrass-dominated diet of turtles larger than 30 cm SCLmax. Animal matter remained a frequently ingested diet item suggesting these immature green turtles are better classified as omnivores. The overall evidence indicates that Texas’ recovering green turtle assemblage is exhibiting foraging plasticity within seagrass meadows changing species composition and density.

Allometric models for sex ratio determination in all stages of ontogeny of Chelonia mydas from Bahía de los Ángeles, México

2020 ◽  
Vol 100 (5) ◽  
pp. 825-830
Author(s):  
Elena Solana-Arellano ◽  
David Ramírez-Delgado ◽  
Erika Santacruz-López
Keyword(s):  
Los Angeles ◽  
Gulf Of California ◽  
Carapace Length ◽  
Principal Component ◽  
Tail Length ◽  
Chelonia Mydas ◽  
Background Information ◽  
Adult Males ◽  
Allometric Models ◽  
Adult Females

AbstractIn order to determine the sex of Chelonia mydas individuals found within one of the principal foraging areas of the Gulf of California during any given stage of ontogeny, 529 individuals were sampled in Bahía de los Ángeles from 1995–2012, and their morphometric data were collected. A principal component analysis (PCA) was performed for the morphometric variables, and two principal components were obtained that unambiguously separated sexes and ontogenetic stages. The first component was defined by straight carapace length (SCL), curve carapace length (CCL), plastron length (PL) and carapace depth (CD), while the second factor was represented by total tail length (TTL). Allometric models were fitted with the most important variables determined by the PCA. The model PL = αSCLβ was able to distinguish between adults and immature individuals. For adult organisms, the model that best separated males from females was TTL = αSCLβ. Adult females had SCL values of 66–96.7 cm and TTL values of 16.3–25 cm, while adult males had SCL values of 66.4–12.5 cm and TTL values > 25 cm. As the organisms were considered immature only if SCL < 77.3, we were able to determine the TTL values for immature individuals by using elemental mathematics and solving for SCL in the equation TTL = αSCLβ for each group (i.e. adult females, adult males and immatures). So, considering the mathematical approach and acknowledging the lack of background information, immature individuals may be considered potential females if the TTL value is between 7.04–17.8 cm and potential males if the TTL value > 17.8 cm.

scholarly journals PRIMEROS REGISTROS DE TORTUGAS BLANCAS Chelonia mydas CON FIBROPAPILOMAS, EN YUCATÁN, MÉXICO

2007 ◽  
Vol 22 (1-2) ◽  
pp. 29
Author(s):  
A. Maldonado-Gasca, ◽  
M. Zapata-Rosales
Keyword(s):  
Green Turtle ◽  
Carapace Length ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Marine Turtles ◽  
Straight Carapace Length ◽  
Green Turtles ◽  
High Prevalence ◽  
Migratory Route

First reports of green turtles Chelonia mydas with fibropapillomas, in Yucatán, México Fibropapillomas are cutaneous tumors that affect the health of marine turtles worldwide. In July 11th of 1998, a juvenile green turtle (Chelonia mydas) with tumors was captured by fishermen in the Sea Turtles Sanctuary of Rio Lagartos, Yucatán. The straight carapace length of this turtle was 44.6 cm, and we found 30 tumors with a size from 1 cm - 10 cm on the back flippers, neck, front flippers and in both eyes. On July 10th, 1999, another juvenile green turtle with fibropapillomatosis was captured by fishermen in the same area. This turtle was smaller (S.C.L. = 40.8 cm) with 5 small tumors (1 cm - 4 cm) on the back flippers and tail. The prevalence of fibro papillomatosis in Yucatan is low (2.4%). Considering the migratory route of this species and the high prevalence of green turtles with fibropapillomas in Florida, USA, we suggest an initial contagion between the populations of these peninsulas. Those are the first documented reports of green turtles with fibropapillomas in Yucatán, México.

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