5 research outputs found
Green turtles (Chelonia mydas) foraging at Arvoredo Island in Southern Brazil: Genetic characterization and mixed stock analysis through mtDNA control region haplotypes
We analyzed mtDNA control region sequences of green turtles (Chelonia mydas) from Arvoredo Island, a foraging ground in southern Brazil, and identified eight haplotypes. Of these, CM-A8 (64%) and CM-A5 (22%) were dominant, the remainder presenting low frequencies (< 5%). Haplotype (h) and nucleotide (π) diversities were 0.5570 ± 0.0697 and 0.0021 ± 0.0016, respectively. Exact tests of differentiation and AMOVA ΦST pairwise values between the study area and eight other Atlantic foraging grounds revealed significant differences in most areas, except Ubatuba and Rocas/Noronha, in Brazil (p > 0.05). Mixed Stock Analysis, incorporating eleven Atlantic and one Mediterranean rookery as possible sources of individuals, indicated Ascension and Aves islands as the main contributing stocks to the Arvoredo aggregation (68.01% and 22.96%, respectively). These results demonstrate the extensive relationships between Arvoredo Island and other Atlantic foraging and breeding areas. Such an understanding provides a framework for establishing adequate management and conservation strategies for this endangered species
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