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- Movement patterns of green turtles at a key foraging site: the Banc d’Arguin, MauritaniaPublication . Mestre, Julie; Patrício, Ana Rita; Sidina, Ebaye; Senhoury, Cheibani; El’bar, Nahi; Beal, Martin; Regalla De Barros, Aissa; Catry, PauloABSTRACT: Interactions with fisheries is a major threat to sea turtles. However, space-use at foraging locations remains overlooked in many populations, preventing effective protection. We assess the space-use of 14 juvenile and 24 adult green turtles (Chelonia mydas) satellite-tracked in 2018–2022 within a foraging site of global importance for this species, the Banc d’Arguin in Mauritania, West Africa. Turtles exhibited a patchy distribution and used overlapping habitats irrespective of sexes and life stages. Mean individual home range was larger (151.5 ± 160.5 km²) than values reported in most green turtle populations. Individuals concentrated in two main areas used year-round. Inshore/offshore movements seem to occur within the central part of the Banc d’Arguin, with turtles moving to deeper areas during colder months. More than half of the turtles performed within-season range shifts and switched between up to four distinct areas, with some individuals returning to previously visited sites. Turtles mostly exploited shallow areas (4.30 ± 3.42 m) and seemed to use disproportionally more of the areas inside the Parc National du Banc d’Arguin, than areas of similar bathymetry outside this marine protected area. This suggests that foraging green turtles have been benefiting from the management of the Park since it was established in 1976. However, turtles’ home range overlapped greatly with artisanal fisheries, which operate in the central shallow waters of the Park. The present study provides valuable ecological information that can be used to inform the planning of fisheries management zones, aiming to reduce the interactions between turtles and artisanal fisheries. © The Author(s) 2024.
- Spatial distribution of inter-nesting green turtles from the largest Eastern Atlantic rookery and overlap with a marine protected areaPublication . Raposo, Cheila; Mestre, Julie; Rebelo, Rui; Regalla De Barros, Aissa; Davies, Alasdair; Barbosa, Castro; Patrício, Ana RitaUnderstanding the spatial distribution of wildlife is fundamental to establish effective conservation measures. Tracking has been key to assess movement patterns and connectivity of sea turtles, yet some regions of great significance are largely understudied. We tracked 44 green turtles from the largest rookery in the Eastern Atlantic, on Poilão Island, Guinea-Bissau, during 2018 through 2020, to assess their inter-nesting movements, connectivity with nearby islands and fidelity to inter-nesting sites. Additionally, we investigated individual and environmental factors that may guide inter-nesting distribution and assessed the adequacy of a marine protected area to support this population during the breeding period. Green turtles had an overall home range of 124.45 km2 , mostly occupying a restricted area around Poilão Island, with 52% of this home range falling within the no-take zone of the João Vieira-Poilão Marine National Park. Turtles exhibited strong fidelity to inter-nesting sites, likely as a strategy to save energy. Only 2 turtles performed significant excursions out of the park, and connectivity between Poilão and nearby islands within the park was limited. Larger turtles and turtles tagged later in the nesting season tended to have smaller core areas and home ranges; thus, experienced breeders may be moving less and potentially benefit from energy saving. This study highlights the importance of a marine protected area for the conservation of one of the largest green turtle breeding populations globally, and provides suggestions for further increasing its effectiveness.