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Advisor(s)
Abstract(s)
ABSTRACT: Understanding population connectivity is paramount for effective conservation.
While genetic tools have elucidated sea turtle migration patterns, notable data gaps limit our
understanding of ocean-wide connectivity, especially regarding east Atlantic green turtles. We
characterized the genetic composition of a globally important green turtle foraging aggregation at
the Banc d’Arguin, Mauritania, incorporating data from 323 individuals captured between 2018
and 2021. Using extended mitochondrial DNA D-loop (738 base pairs [bp]) and mitochondrial short
tandem repeat (mtSTR; ~200 bp) markers, we assessed the genetic structure of Atlantic green turtle
foraging aggregations and estimated the most likely origin of immature green turtles from the Banc
d’Arguin using mixed stock analyses (MSAs). We identified 6 D-loop haplotypes, with a clear
dominance of CM-A8.1 (91.8%) followed by CM-A5.1 (6.3%) and 4 rare haplotypes: CM-A1.4,
CMA6.1, CM24.1 and CM36.1. We found 13 mtSTR haplotypes, with ‘7-12-4-4’ being dominant
(89.0%). The genetic composition at the Banc d’Arguin differed significantly from the only foraging
aggregation studied in West Africa to date — in the archipelago of Cabo Verde (located ca. 750 km
from the Banc d’Arguin) — dominated by haplotype CM-A5. The MSA combining both genetic
markers indicated that 87.6% of immature green turtles at the Banc d’Arguin originate from the
major East Atlantic rookery at Poilão (Guinea-Bissau), but 11.6% come from more distant rookeries
in South America (8.1%) and potentially Ascension Island (3.4%). We suggest that green turtle
transatlantic movements may be more common than previously thought and highlight the importance of the Banc d’Arguin as a regional foraging hub for this species.
Description
Keywords
Sea turtles Population genetics Migratory connectivity Dispersal Foraging grounds Mixed-stock analysis mtDNA Atlantic Ocean
Citation
Patrício, A. R., Hancock, J. M., Broderick, A. C., Godley, B. J., Tilley, D., Weber, S., Coveney, S. A., Barbanti, A., Barbosa, C., Regalla, A., El, B. N., Senhoury, C., Sidina, E., Catry, P., & de Thoisy, B. (2024). Atlantic connectivity of a major green sea turtle Chelonia mydas foraging aggregation at the Banc d’Arguin, Mauritania. Endangered Species Research, 54, 365–382. https://doi.org/10.3354/esr01345
Publisher
Inter-Research