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Tropical tuna purse seiners extensively use drifting Fish Aggregating Devices (dFADs), human-made floating objects deployed by fishers to facilitate the capture of tunas. The majority of drifting Fish Aggregating Devices (dFADs) in use today are constructed primarily of highly durable non-biodegradable synthetic materials. There is currently no legal obligation to recover dFADs after deployment, which leads to beaching events. To ascertain the extent of beachings within a local context, we analysed all identified beaching events (n=3,775) in the Seychelles Archipelago found among trajectories of dFADs deployed by French purse seiners during 2010-2020 as a function of intra- and inter-annual trends, water depth and distance from land, seasonality and benthic habitat. Beachings occurred most frequently during the (boreal) winter monsoon (December-March). Due the extended shallow Mahé Plateau, beaching occurred in both nearshore (≤5 km from land, 0-40m water depth) and offshore regions (>5 km, 0-60m depth). Despite representing <20% of the overall mapped habitat, the majority of beachings occurred within the benthic habitat ‘Coral/Algae’ (38.1%), and therefore, pose a significant concern for conservation. Our results provide a detailed view of the spatiotemporal pattern of beachings and suggest recovery efforts be directed to reduce marine debris and perturbations of coastal habitats.
