Biquet J. A. auteur aut IRD Tixier Paul auteur aut IRD Richard G. auteur aut IRD Soehnlen M. auteur aut IRD Thellier T. auteur aut IRD Carzon P. auteur aut IRD Clua E. auteur aut IRD Guinet C. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Marine megafauna feeding on fishery catches (depredation) or being incidentally caught on fishing gear (bycatch) have become important issues. Their socioeconomic and conservation stakes have been increasingly studied across the world fisheries. They remain understudied in the Pacific Ocean, where longline tuna fisheries reported such interactions. In this study, we provide the first assessment of bycatch and depredation by sharks and odontocetes on longlines in French Polynesia between 2000 and 2018, using data from observers reporting, captains' logbooks, questionnaires and additional monitoring by authors during three fishing trip. We found that less than 2% of the catch had been depredated, and that shark depredation was more common than odontocete depredation. Shark bycatch was important (20,000 sharks annually, 0.5 shark every 1000 hooks) and odontocete bycatch seemed low (13 occurrences in 18 years), though we identified clear reporting flaws. We discuss the range of uncertainty associated with our assessment, based on the current reporting systems, and the potential consequences of depredation and bycatch on tuna fisheries, as well as on shark and odontocete populations in French Polynesia. specialized Fisheries Elasmobranch and cetacean conservation Depredation Bycatch Pacific POLYNESIE FRANCAISE PACIFIQUE 040 082 271 106928 [12 ] 2024 0165-7836 https://www.documentation.ird.fr/hor/fdi:010088961 10.1016/j.fishres.2023.106928 0165-7836 [F B010088961] https://www.documentation.ird.fr/hor/fdi:010088961 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-03/010088961.pdf IRD - Base Horizon / Pleins textes 2024-03-06 2025-11-06 fdi:010088961 fre