Albacore tuna (Thunnus alalunga) habitat and variability in French Polynesia

Abstract

Albacore tuna is important for the economy and food industry of French Polynesia. Nowadays, it represents 55% of the offshore fishery. With its lower resilience to climate change, relative to other tuna species, albacore requires focused study. This study investigates albacore’s spatial distribution and relative abundance within the FP Exclusive Economic Zone (FP-EEZ) by analysing monthly fishery data from 2000 to 2022.

Environmental parameters influencing Catch Per Unit Effort (CPUE) are assessed using a Generalized Additive Model (GAM) to define preferred habitat of albacore tuna. The parameters include sea surface temperature (SST), dissolved oxygen (DO) at 100m, chlorophyll concentration (Chl), sea surface salinity (SSS), and zonal and meridional currents. GAMs have the possibility to analyses past data in order to create a model that can predict on short and long-term time scale. Our results reveal a clear seasonal variability with a peak between May and December, and a pronounced interannual variation linked to El Niño Southern Oscillation. Our data show that part of the FP-EEZ is a spawning ground for albacore tuna, providing critical insights for sustainable fisheries management. GAM is a powerful tool to help making decisions as for a proper management of fishery resource in French Polynesia EEZ.