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

This paper presents complementary information on the Associative Behavior-Based abundance Index
(ABBI) for the western Indian Ocean skipjack tuna (Katsuwonus pelamis) presented in paper IOTC-
2023-WPTT25(DP)-12. Using data from 2013-2022, we show that the ABBI is robust to the addition of
new data to the time series. Estimates of the quarterly relative abundance per 10° × 10° strata and of the
ratio between abundances of free-swimming and associated skipjack tuna are also provided, as
requested during the WPTT25 Data Preparatory Meeting.