Bonnin L. auteur aut IRD Lett Christophe auteur aut IRD Dagorn Laurent auteur aut IRD Filmalter J. D. auteur aut IRD Forget Fabien auteur aut IRD Verley Philippe auteur aut IRD Capello Manuela auteur aut IRD text journalArticle eng text/pdf born digital access Juvenile silky sharks (Carcharhinus falciformis)regularly associate with floating objects yet the reasons driving this behaviour remain uncertain. Understanding the proportion of time that silky sharks spend associated with floating objects is essential for assessing the impacts of the extensive use of fish aggregating devices (FADs) in the tropical tuna purse-seine fisheries, including increased probability of incidental capture and the potential of an ecological trap. Previous studies provided insight into the amount of time that silky sharks spent at an individual FAD but were unable to assess neither the time spent between two associations nor the proportion of time spent associated/unassociated. The percentage of time that juvenile silky sharks spend unassociated with floating objects was estimated through the analysis of horizontal movements of 26 silky sharks monitored with pop-up archival tags. Under the assumption that a high association rate with drifting FADs would align the trajectories of tracked sharks with ocean surface currents, a novel methodology is proposed, based on the comparison of shark trajectories with simulated trajectories of passively drifting particles derived using a Lagrangian model. Results revealed that silky shark trajectories were divergent from surface currents, and thus unassociated with FADs, for at least 30% of their time. The potential of the methodology and the results are discussed in the context of increasing FAD densities in the Indian Ocean. specialized bycatch fish aggregating devices Lagrangian drift model pop-up satellite archival telemetry silky shark vulnerability OCEAN INDIEN SEYCHELLES 034 040 020 126 32 1 74-82 2021 1052-7613 https://www.documentation.ird.fr/hor/fdi:010079498 10.1002/aqc.3420 1052-7613 [F B010079498] https://www.documentation.ird.fr/hor/fdi:010079498 https://www.documentation.ird.fr/intranet/publi/2020/09/010079498.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-10-09 2025-02-24 fdi:010079498 fre