Lopetegui-Eguren L. auteur aut IRD Poos J. J. auteur aut IRD Arrizabalaga H. auteur aut IRD Guirhem G. L. auteur aut IRD Murua H. auteur aut IRD Lezama-Ochoa N. auteur aut IRD Griffiths S. P. auteur aut IRD Gondra J. R. auteur aut IRD Sabarros Philippe auteur aut IRD Baez J. C. auteur aut IRD Juan-Jorda M. J. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Oceanic whitetip shark (Carcharhinus longimanus) is an important top predator in pelagic ecosystems currently classified as globally Critically Endangered by the International Union for the Conservation of Nature. This species is incidentally caught by fisheries targeting highly migratory tunas and billfishes throughout the Indian Ocean. Understanding the temporal, spatial and environmental factors influencing the capture of this species is essential to reduce incidental catches. In this study, we used generalized additive models to analyze the spatio-temporal distributions of the juvenile oceanic whitetip shark catches and the environmental conditions in the western Indian Ocean using observer data from 2010 to 2020 of the European Union and associated flags purse seine fishery. We found sea surface temperature and nitrate concentration to be the most important environmental variables predicting the probability of catching an oceanic whitetip shark. A higher probability of capture was predicted in areas where sea surface temperature was below 24 degrees C and with low nitrate concentrations close to zero and intermediate values (1.5-2.5 mmol.m(-3)). We also found a higher probability of capture in sets on fish aggregating devices than in sets on free schools of tuna. The Kenya and Somalia basin was identified to have higher probabilities of capture during the summer monsoon (June to September) when upwelling of deep cold waters occurs. We provide the first prediction maps of capture probabilities and insights into the environmental preferences of oceanic whitetip shark in the western Indian Ocean. However, the causal mechanisms behind these insights should be explored in future studies before they can be used to design spatial management and conservation strategies, such as time-area closures, for bycatch avoidance. specialized oceanic whitetip shark species distribution model bycatch species tropical tuna purse-seine fishery Western Indian Ocean OCEAN INDIEN 040 021 020 9 863602 [19 p.] 2022 https://www.documentation.ird.fr/hor/fdi:010085260 10.3389/fmars.2022.863602 [F B010085260] https://www.documentation.ird.fr/hor/fdi:010085260 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2022-09/010085260.pdf IRD - Base Horizon / Pleins textes 2022-09-02 2025-02-24 fdi:010085260 fre