Quota and catch concentration in fisheries under the ITQ system: Insights from bluefin tuna in the Strait of Gibraltar

Abstract

The Individual Transferable Quota (ITQ) system is widely regarded as an effective policy tool to regulate fishing, to maintain the economic level, and to promote the sustainability of resources. However, its implementation can influence the distribution of quotas, potentially leading to changes in the economic structure of the sector, which raises concerns about the future of small-scale vessels. This study evaluates the impact of ITQs on bluefin tuna (Thunnus thynnus) in the Ports of the Strait of Gibraltar, where ITQs have been applied since 2008. To analyze these effects, we use Lorenz curves and Gini indices to examine the evolution of catches and income. The results reveal that the application of ITQs has reinforced the concentration of economic activity in these ports. Based on these findings, we propose a new ITQ distribution to ensure the economic viability of small-scale vessels and to address the concentration caused by the current ITQ system. Our redistribution proposal focuses on reallocating quotas to vessels that no longer catch bluefin tuna as bycatch and those that currently have low allocations. This paper provides insights into the economic consequences of rigid quota allocation systems that may be relevant to fisheries facing similar challenges worldwide.