Baidai Y. auteur aut IRD Dupaix A. auteur aut IRD Dagorn Laurent auteur aut IRD Gaertner Daniel auteur aut IRD Deneubourg J. L. auteur aut IRD Duparc Antoine auteur aut IRD Capello Manuela auteur aut IRD text journalArticle eng text/pdf reformatted digital access Managing populations of wild harvested species requires the ability to regularly provide accurate abundance assessments. For most marine species, changes in abundance can only be monitored indirectly, using methods reliant on harvest-based indices, with significant inherent limitations surrounding the estimation and standardization of harvest effort. Tropical tunas are some of the most exploited marine species in the world and are among several species in critical need of alternative methods for estimating abundance. Addressing this concern, we developed the Associative Behaviour-Based abundance Index (ABBI), designed to provide direct abundance estimates for animals, which exhibit an associative behaviour with aggregation sites. Its implementation in the western Indian Ocean on skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares) and bigeye tuna (Thunnus obesus), revealed similar trajectories in their relative abundance. The ABBI stands as a potentially promising alternative to enhance traditional tropical tuna stock assessments methods, as well as a new opportunity to assess the abundance of other wild species that display an associative behaviour with physical structures found in their natural environment. specialized direct abundance index associative behaviour tropical tunas echosounder buoys OCEAN INDIEN 040 036 291 2029 20241132 [11 ] 2024 0962-8452 https://www.documentation.ird.fr/hor/fdi:010091261 10.1098/rspb.2024.1132 0962-8452 [F B010091261] https://www.documentation.ird.fr/hor/fdi:010091261 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2024-10/010091261.pdf IRD - Base Horizon / Pleins textes 2024-10-23 2025-11-06 fdi:010091261 fre