Associative Behavior-Based abundance Index (ABBI) for western Indian Ocean skipjack tuna (Katsuwonus pelamis) obtained from echosounder buoys data.

This paper presents the abundance estimates of skipjack tuna (Katsuwonus pelamis) using the Associative Behavior-Based abundance Index (ABBI). By taking advantage of the associative behavior of species around floating objects (FOBs) and acoustic data collected by echosounder buoys used in the tropical tuna purse seine fishery, the ABBI approach provides direct and effort-independent estimates of tropical tuna abundance. Its implementation in the western Indian Ocean for skipjack has shown that the decline in abundance of this species observed since 2018 is shifting towards a stabilization trend of abundance around 2013 levels from 2020 onwards.