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Atlantic-wide connectivity of Ascension Island green turtles revealed by finer-scale mitochondrial DNA markers

Sophia Coveney, Eva Jiménez-Guri Orcid Logo, Samantha Ball Orcid Logo, Nathalie Mianseko, Annette C. Broderick Orcid Logo, Brendan J. Godley Orcid Logo, Joana M. Hancock Orcid Logo, Welton Quirino Pereira, Aissa Regalla Orcid Logo, Rita Gomes Rocha Orcid Logo, Cheibani Senhoury, Benoit de Thoisy Orcid Logo, Dominic Tilley Orcid Logo, Sarah Maria Vargas Orcid Logo, Sam B. Weber Orcid Logo, Ana Rita Patrício Orcid Logo

Conservation Genetics

Swansea University Author: Sophia Coveney

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Abstract

Marine turtles undertake long migrations across different geographies and habitats, exposing them to a wide range of threats throughout their lifespan. Analysing population structure and connectivity is key to informing effective conservation management. We expand knowledge of Atlantic-wide connecti...

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Published in: Conservation Genetics
ISSN: 1566-0621 1572-9737
Published: Springer Science and Business Media LLC 2025
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URI: https://cronfa.swan.ac.uk/Record/cronfa70122
Abstract: Marine turtles undertake long migrations across different geographies and habitats, exposing them to a wide range of threats throughout their lifespan. Analysing population structure and connectivity is key to informing effective conservation management. We expand knowledge of Atlantic-wide connectivity of green turtles (Chelonia mydas) by characterising the genetic structure of the Ascension Island nesting population, one of the largest in the Atlantic Ocean, and carrying out Atlantic population structure and mixed stock analyses using high-resolution genetic markers. We amplified a ~ 738 bp fragment (extended D-loop) and a highly polymorphic mitochondrial short tandem repeat (mtSTR) fragment of the mitochondrial DNA control region, designating haplotypes based on (1) extended D-loop and (2) the extended D-loop and mtSTR combined. Overall, 11 extended D-loop and 33 combined haplotypes were found, the dominant haplotypes being CM-A8.1 and CM-A8.1/7-12-4-4. Population structure analysis found three main genetic groups: Northwest Atlantic, Northern South America, and South and East Atlantic. Mixed stock analyses indicate Ascension Island as a major source for juvenile foraging aggregations in the Southwest Atlantic (34–55%) and Central Africa (18–78%), with some contribution to West Africa (3–20%). Green turtles are vulnerable to fishery bycatch in the coastal waters of the South and East Atlantic. Our study underlines how improving sample sizes of Atlantic mtSTR haplotypes could further elucidate green turtle connectivity across threatened regions. We urge international collaboration to minimise mtSTR data gaps, in order to enhance connectivity assessments and improve conservation measures between countries that share populations.
Keywords: mtDNA; Chelonia mydas; mtSTR; Population genetics; Mixed stock analysis; Sea turtles
College: Faculty of Science and Engineering
Funders: Fundação Renova (Technical-Scientific Cooperation Agreement n◦ 30/2018 with FEST - Brazil); Fundação do Estado do Espírito Santo, Brazil (Scholarship #143/2022); Fundação para a Ciência e a Tecnologia (2022-00505.CEECIND, 2023.07021.CEECIND/CP2831/CT0012); Natural Environment Research Council (NE/L009501/1).