Overcapacity and dynamics of a tuna fleet facing catch limits and high efficiency: The case of the Indian Ocean tuna fishery

Abstract

The Indian Ocean Tuna Commission (IOTC) expresses concern over the overfished state and susceptibility to the overfishing of yellowfin tuna (Thunnus albacares). Acknowledging the challenges of increased fishing effort in a profitable fishery, our study aims to understand factors influencing French purse seine fishing vessel dynamics. Our primary goal is to assess purse seine vessel utilisation with recent catch limits and compliance with the European Union Common Fisheries Policy (CFP), which mandates measures to align fishing capacity with opportunities to sustain fish stocks at maximum sustainable yield (MSY). Using Data Envelopment Analysis, we evaluate the relationship between vessel fishing capacity to catch limits and the MSY reference point for yellowfin tuna. Random Utility Models identify key drivers influencing the fleets' strategic decisions, rigorously assessed with a machine-learning algorithm. Findings indicate that the French fleet could meet catch limits with approximately 21% fewer vessels if fully utilised and 26% fewer if reduced to meet their equivalent MSY share. Key influencing factors include catch revenue, vessel age, biomass levels, and interest rates. The predictive model achieves a 93% accuracy rate, essential for effectively implementing regional conservation policies that balance economic stakes with sustainable fishing practices. Aligning capacity with fishing opportunities is crucial for the profitability and preservation of these essential tuna populations, resulting in more sustainable and economically viable fisheries.