6 research outputs found
Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific
Mitochondrial DNA analyses have been useful for resolving maternal lineages and migratory behavior to foraging grounds (FG) in sea turtles. However, little is known about source rookeries and haplotype composition of foraging green turtle aggregations in the southeastern Pacific. We used mitochondrial DNA control region sequences to identify the haplotype composition of 55 green turtles, Chelonia mydas, captured in foraging grounds of Gorgona National Park in the Colombian Pacific. Amplified fragments of the control region (457 bp) revealed the presence of seven haplotypes, with haplotype (h) and nucleotide (π) diversities of h = 0.300±0.080 and π = 0.009±0.005 respectively. The most common haplotype was CMP4 observed in 83% of individuals, followed by CMP22 (5%). The genetic composition of the Gorgona foraging population primarily comprised haplotypes that have been found at eastern Pacific rookeries including Mexico and the Galapagos, as well as haplotypes of unknown stock origin that likely originated from more distant western Pacific rookeries. Mixed stock analysis suggests that the Gorgona FG population is comprised mostly of animals from the Galapagos rookery (80%). Lagrangian drifter data showed that movement of turtles along the eastern Pacific coast and eastward from distant western and central Pacific sites was possible through passive drift. Our results highlight the importance of this protected area for conservation management of green turtles recruited from distant sites along the eastern Pacific Ocean
Linking loggerhead locations: using multiple methods to determine the origin of sea turtles in feeding grounds
Multinational Tagging Efforts Illustrate Regional Scale of Distribution and Threats for East Pacific Green Turtles (Chelonia mydas agassizii)
Mixed stock analysis of juvenile green turtles aggregating at two foraging grounds in Fiji reveals major contribution from the American Samoa Management Unit
Genetic structure and natal origins of immature hawksbill turtles (Eretmochelys imbricata) in Brazilian waters
Understanding the connections between sea turtle populations is fundamental for their effective conservation. Brazil hosts
important hawksbill feeding areas, but few studies have focused on how they connect with nesting populations in the
Atlantic. Here, we (1) characterized mitochondrial DNA control region haplotypes of immature hawksbills feeding along the
coast of Brazil (five areas ranging from equatorial to temperate latitudes, 157 skin samples), (2) analyzed genetic structure
among Atlantic hawksbill feeding populations, and (3) inferred natal origins of hawksbills in Brazilian waters using genetic,
oceanographic, and population size information. We report ten haplotypes for the sampled Brazilian sites, most of which
were previously observed at other Atlantic feeding grounds and rookeries. Genetic profiles of Brazilian feeding areas were
significantly different from those in other regions (Caribbean and Africa), and a significant structure was observed between
Brazilian feeding grounds grouped into areas influenced by the South Equatorial/North Brazil Current and those influenced
by the Brazil Current. Our genetic analysis estimates that the studied Brazilian feeding aggregations are mostly composed of
animals originating from the domestic rookeries Bahia and Pipa, but some contributions from African and Caribbean
rookeries were also observed. Oceanographic data corroborated the local origins, but showed higher connection with West
Africa and none with the Caribbean. High correlation was observed between origins estimated through genetics/rookery
size and oceanographic/rookery size data, demonstrating that ocean currents and population sizes influence haplotype
distribution of Brazil’s hawksbill populations. The information presented here highlights the importance of national
conservation strategies and international cooperation for the recovery of endangered hawksbill turtle populations