Mixed Stock Analysis of Juvenile Hawksbill Sea Turtles (Eretmochelys Imbricata) at Brewers Bay and Hawksbill Cove, St. Thomas, USVI

Mixed Stock Analysis of Juvenile Hawksbill Sea Turtles (Eretmochelys Imbricata) at Brewers Bay and Hawksbill Cove, St. Thomas, USVI
Author: Jessica N. Levenson
Publisher:
Total Pages: 43
Release: 2020
Genre: Hawksbill turtle
ISBN:
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Marine turtles’ complex life histories present substantial challenges in identifying population boundaries and relationships due to their highly migratory behaviors, philopatry, and wide dispersal throughout large areas of tropical and subtropical latitudes. Mitochondrial DNA (mtDNA) research has identified rookery-specific haplotypes that represent isolated populations with potentially limited gene flow, which results in nesting populations having a unique genetic signature. Juvenile populations at dispersed foraging grounds are composed of a diverse genetic mixture from multiple nesting locations. Analysis of the genetic composition of turtles from foraging locations could inform general life history patterns like the variations in habitat use, migration, and dispersal and suggest the natal origin of specific populations. Brewers Bay and Hawksbill Cove (BBHC), in St Thomas US Virgin Islands has been the site of in water research on the movement and behavior of hawksbill sea turtles (Eretmochelys imbricata). However, no studies have focused on how they connect with nesting populations in the Caribbean. Therefore, we collected tissue samples from 59 juvenile hawksbill turtles that were hand-captured to genetically characterize the structure of this foraging ground using mitochondrial DNA. All turtles captured were within the juvenile size class and ranged from 19.5 cm to 65.0 cm curved carapace length. Recapture rates confirm residency within BBHC with 32 individuals being recaptured at least once between 2014 and 2019. Ten haplotypes were found; EiA01 appeared 24 times, EiA11 appeared 14 times, EiA09 appeared 6 times, EiA83 appeared 4 times, EiA02, EiA24, EiA41, and EiA43 each appeared 2 times, and EiA12 and EiA23 each appeared 1 time. These haplotypes were compared against previously characterized rookeries throughout the Caribbean to determine the most likely origins for the St. Thomas population. An analysis of the ten haplotypes using the program BAYES suggested that the biggest contributing source to this juvenile population was the leeward side of Barbados, with lesser but notable contributions from nesting populations from windward side of Barbados, Nicaragua, Guadeloupe, and Sandy Point, St. Croix. The results presented from this study are an important contribution to the baseline data of foraging ground connections to natal beaches, which is essential for designing management plans for population recovery.

Diet and Habitat Use of Juvenile Hawksbill Turtles (Eretmochelys Imbricata) in the Gulf of California, Mexico

Diet and Habitat Use of Juvenile Hawksbill Turtles (Eretmochelys Imbricata) in the Gulf of California, Mexico
Author: Kara Satomi Reynolds
Publisher:
Total Pages: 33
Release: 2021
Genre:
ISBN:
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The hawksbill sea turtle (Eretmochelys imbricata) is an endangered species thought to spend their juvenile years in protected, nearshore areas before returning to their natal beaches to breed. We caught, measured, and sampled skin and anterior and posterior scutes from hawksbill turtles in a foraging ground around Isla San Jose, Gulf of California, Mexico. We analyzed the [delta]13C and [delta]15N values from tissues taken from mostly juvenile (96.4%) individuals, based upon morphometric measurements, as well as potential prey items to assess their foraging habits. A Bayesian mixing model analysis of the stable isotope values indicated hawksbills are consuming a primarily invertebrate-based diet supplemented by foraging on plant matter composed largely of seagrass and algae. The [delta]13C values from posterior scute samples increased with age, suggesting a potential location shift as younger turtles move from a more pelagic habitat to the nearshore foraging area at Isla San Jose.

Juvenile Dispersal and Genetic Connectivity in the Sea Turtle 'Lost Years'

Juvenile Dispersal and Genetic Connectivity in the Sea Turtle 'Lost Years'
Author: Katrina F. Phillips
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:
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Juvenile dispersal is a life history strategy found across taxa and habitat types. In this dissertation, I examine juvenile dispersal in an evolutionary context and explore the conditions that support high dispersal, which necessitates subsequent ontogenetic habitat shifts. I use a sea turtle study system to evaluate the genetic and behavioral patterns associated with juvenile dispersal and ontogenetic shifts in marine environments. Specifically, I focus on four sea turtle species found in the northeastern Gulf of Mexico in the early life stage known as the ‘lost years’: green turtles (Chelonia mydas), Kemp’s ridleys (Lepidochelys kempii), loggerheads (Caretta caretta), and hawksbills (Eretmochelys imbricata). I use mitochondrial DNA (mtDNA) haplotypes and ocean transport probabilities to estimate contributions from source rookeries to sampling sites in the Gulf of Mexico as well as assess gaps in the available genetic datasets. The mixed stock analyses indicate that the majority of ‘lost years’ green turtles I sampled originate from nesting beaches along the coast of Mexico, with smaller contributions from Costa Rica and Suriname. More broadly, I identify gaps in available genetic data across species, life stages, and ocean basins, particularly among early juveniles. I use telemetry data to characterize sea turtle ‘lost years’ movements with respect to the continental shelf and proximity to the coast, potential recruitment to coastal habitats, and passive versus active behavior by using oceanographic surface drifters as a control. The West Florida Shelf is a high-use area, particularly among green turtles and Kemp’s ridleys. Finally, I analyze genome-wide single nucleotide polymorphisms to test whether mtDNA haplotype data accurately reflect overall population structure for defining management units. These data provide valuable insight into the elusive ‘lost years’ juvenile dispersal life stage in sea turtles and fill substantial data gaps impeding management for species conservation.

Genetic Characterization of Hawksbill Turtles (Eretmochelys Imbricata) in the Eastern Pacific Ocean

Genetic Characterization of Hawksbill Turtles (Eretmochelys Imbricata) in the Eastern Pacific Ocean
Author: Alexander Richard Gaos
Publisher:
Total Pages:
Release: 2017
Genre:
ISBN: 9780355150827
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The hawksbill marine turtle (Eretmochelys imbricata) is a highly threatened species whose conservation status is particularly precarious in the eastern Pacific Ocean, where it is estimated that

The Leatherback Turtle

The Leatherback Turtle
Author: James R. Spotila
Publisher: JHU Press
Total Pages: 246
Release: 2015-10-30
Genre: Science
ISBN: 142141709X
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The most comprehensive book ever written on leatherback sea turtles. Weighing as much as 2,000 pounds and reaching lengths of over seven feet, leatherback turtles are the world’s largest reptile. These unusual sea turtles have a thick, pliable shell that helps them to withstand great depths—they can swim more than one thousand meters below the surface in search of food. And what food source sustains these goliaths? Their diet consists almost exclusively of jellyfish, a meal they crisscross the oceans to find. Leatherbacks have been declining in recent decades, and some predict they will be gone by the end of this century. Why? Because of two primary factors: human redevelopment of nesting beaches and commercial fishing. There are only twenty-nine index beaches in the world where these turtles nest, and there is immense pressure to develop most of them into homes or resorts. At the same time, longline and gill net fisheries continue to overwhelm waters frequented by leatherbacks. In The Leatherback Turtle, James R. Spotila and Pilar Santidrián Tomillo bring together the world’s leading experts to produce a volume that reveals the biology of the leatherback while putting a spotlight on the conservation problems and solutions related to the species. The book leaves us with options: embark on the conservation strategy laid out within its pages and save one of nature’s most splendid creations, or watch yet another magnificent species disappear.

Pacific Presences

Pacific Presences
Author: Lucie Carreau
Publisher:
Total Pages:
Release: 2018
Genre: ART
ISBN: 9789088905919
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Hundreds of thousands of works of art and artefacts from many parts of the Pacific are dispersed across European museums. They range from seemingly quotidian things such as fish-hooks and baskets to great sculptures of divinities, architectural forms and canoes. These collections constitute a remarkable resource for understanding history and society across Oceania, cross-cultural encounters since the voyages of Captain Cook, and the colonial transformations that have taken place since. They are also collections of profound importance for Islanders today, who have varied responses to their disp.