Climate-Driven Shift of Immature Albacore: Potential Habitat Alterations in the Indian Ocean

Abstract

Climate change is causing significant changes in maritime habitats, altering the distribution of marine organisms and potentially leading to poleward migration of species, impacting fishing operations and coastal communities' subsistence methods. The present study analyzed the distribution of the Indian Ocean immature albacore tuna (Thunnus alalunga) by using an ensemble modeling approach and considering three representative concentration pathway (RCP) scenarios (2.6, 4.5 and 8.5) to assess the implications of predicted climate change. Three species distribution models (generalized additive modeling, boosted regression tree, and random forest) incorporating various oceanographic parameters were used as inputs to create an ensemble model that replicated the immature albacore distribution. The study period revealed that the distribution of immature albacore tuna was primarily concentrated between 28 degrees S and 34 degrees S in the Indian Ocean. The findings indicated a substantial disparity in the distribution of immature albacore tuna by the year 2100, with RCP 8.5 showing a notable contrast to RCP 2.6. The projected distribution range under RCP 8.5 is expected to significantly change by 2100, with an estimated range of 38 degrees S-41 degrees S, compared to 30 degrees S-34 degrees S under RCP 2.6. By integrating these outcomes into managerial strategies, decision-makers can make informed decisions that not only protect the other fisheries of the Indian Ocean but also safeguard the livelihoods of the people who rely on them in the face of changing climatic conditions.