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- Key issues in assessing threats to sea turtles: Knowledge gaps and future directionsPublication . Fuentes, Mariana M. P. B.; McMichael, Erin; Kot, Connie Y.; Silver-Gorges, Ian; Wallace, Bryan P.; Godley, Brendan; Brooks, Annabelle M. L; Ceriani, Simona A; Cortés-Gómez, Adriana A.; Dawson, Tiffany M.; Dodge, Kara L.; Flint, Mark; Jensen, Michael P; Komoroske, Lisa M.; Kophamel, Sara; Lettrich, Matthew; Long, Christopher A.; Nelms, Sarah E.; Patrício, Ana Rita; Robinson, Nathan J.; Seminoff, Jeffrey; Ware, Matthew; Whitman, Elizabeth R.; Chevallier, Damien; Clyde-Brockway, Chelsea E.; Korgaonkar, Sumedha A.; Mancini, Agnese; Mello-Fonseca, J; Monsinjon, Jonathan; Neves-Ferreira, Isabella; Ortega, Anna A.; Patel, Samir H.; Pfaller, Joseph B.; Ramirez, Matthew D.; Raposo, Cheila; Smith, Caitlin E.; Abreu-Grobois, F. Alberto; Hays, Graeme C.Sea turtles are an iconic group of marine megafauna that have been exposed to multiple anthropogenic threats across their different life stages, especially in the past decades. This has resulted in population declines, and consequently many sea turtle populations are now classified as threatened or endangered globally. Although some populations of sea turtles worldwide are showing early signs of recovery, many still face fundamental threats. This is problematic since sea turtles have important ecological roles. To encourage informed conservation planning and direct future research, we surveyed experts to identify the key contemporary threats (climate change, direct take, fisheries, pollution, disease, predation, and coastal and marine development) faced by sea turtles. Using the survey results and current literature, we also outline knowledge gaps in our understanding of the impact of these threats and how targeted future research, often involving emerging technologies, could close those gaps.
- Satellite tracking and field assessment highlight major foraging site for green turtles in the Banc d'Arguin, MauritaniaPublication . Catry, Paulo; Senhoury, Cheibani; Sidina, Ebaye; El Bar, Nahi; Samba Bilal, Abdellahi; Ventura, Francesco; Godley, Brendan; Pires, António A.; Regalla, Aissa; Patrício, Ana RitaThere is a remarkable paucity of estimates of the numeric importance of sea turtles at foraging grounds. The Banc d'Arguin (BA) is a vast shallow marine area off the coast of Mauritania, known as a site of world importance for coastal migratory birds and other biodiversity, including extensive seagrass beds. We sampled foraging green turtles on the BA, and extensively tracked adult female green turtles from the Bijagós archipelago, the only significant nesting aggregation within 3000 km of the BA, to estimate the abundance of this foraging aggregation. Additionally, we used a demographic simulation to support our findings. Based on satellite tracking of adult females (n = 46), we estimate that 50 % of the nesting population from the Bijagós migrate to the BA post-nesting. We combine data on numbers nesting in the Bijagós with information on proportion migrating to the BA in the same years to conservatively estimate that 8285 adult female green turtles forage at this site. We also estimate that adult females represent only 5.6 % of the green turtles in the BA, implying that the number of turtles there is of the order of 150,000 individuals. Most of the BA enjoys effective protection as part of the Parc National du Banc d'Arguin where significant fisheries regulations are well enforced by a marine surveillance program. We show that the BA is one of the major foraging sites for green turtles nesting in the Bijagós and a site of critical importance for immature and adult green turtles in a global context.
- Atlantic connectivity of a major green sea turtle Chelonia mydas foraging aggregation at the Banc d’Arguin, MauritaniaPublication . Patrício, Ana Rita; Coveney, Sophia A.; Barbanti, Anna; Barbosa, Castro; Broderick, Annette; El’Bar, Nahi; Godley, Brendan; Hancock, Joana M.; Regalla De Barros, Aissa; Senhoury, Cheibani; Sidina, Ebaye; de Thoisy, Benoît de; Tilley, Dominic; Weber, Sam; Catry, PauloABSTRACT: 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.