TROPIVarBi

Context

The fishery resources of tropical tunas (skipjack, yellowfin and bigeye), which are among the main species used by the canning industry, are distributed throughout the tropical and subtropical regions of the world’s oceans. Since the mid-20th century, these species have been subject to increasing levels of exploitation. Longline fleets began operating in the 1950s, but it was from the 1970s onwards that these fisheries expanded significantly with the development of purse-seine fleets, which began supplying the canning market on a regular basis. Since then, the increase in the number and capacity of vessels, together with the expansion of fishing grounds, has made tropical tuna fisheries some of the most important fisheries worldwide (FAO, 2006).

In this context, the Basque freezer tuna purse-seine fleet has a significant presence in the Atlantic and Indian Oceans, supplying raw material to a large part of the Basque canning industry. For several years, AZTI has played an active role in the international organisations responsible for managing tuna stocks in these oceans: ICCAT in the Atlantic and IOTC in the Indian Ocean. These organisations structure their work around species working groups, a scientific committee and the commission. The working groups are responsible for stock assessments and for analysing the available information on the status and dynamics of tuna populations. The scientific committee consolidates this information and develops management recommendations, while the commission is the decision-making forum where countries agree on management measures.

Objectives

The overall objective is to contribute to comprehensive stock assessments and the development of scientific recommendations for the management of tropical tunas (yellowfin, bigeye and skipjack), which are of major importance to the Basque fishing sector in the Atlantic and Indian Oceans.

The specific objectives are:

• To participate actively in the scientific committees of ICCAT and IOTC, attending working groups and contributing to stock assessments. In 2025, bigeye tuna assessments will be carried out in both oceans, alongside further progress on Management Strategy Evaluation (MSE), with a particular focus on the Atlantic.
• To respond to specific requests and provide the Basque Government and the fishing sector with information on the status of tropical tuna resources and related issues.
• To communicate the recommendations arising from the scientific committees to the fishing sector.
• To develop tools for assessing different management strategies applicable to the freezer tuna fleet.
• To carry out studies on the biology and population dynamics of tropical tunas in the Atlantic and Indian Oceans, contributing to their sustainable management.
• To promote scientific dissemination, both through high-impact scientific journals and publications aimed at a wider audience.

Expected impact

The continued participation of AZTI experts in IOTC and ICCAT working groups will strengthen the role of science in the main international forums, contributing scientific leadership and greater capacity to inform decision-making. Working documents are expected to be presented to the working groups of both organisations, alongside the publication of scientific papers in leading journals and outreach materials for the general public.

The main impact of this project lies in the importance of tropical tunas for numerous fishing fleets, including the Basque fleet, and in the need to ensure their sustainable exploitation. AZTI researchers currently hold leadership positions, including the chairmanship of the IOTC Working Party on Tropical Tunas and other positions of responsibility, giving them a prominent role in international fisheries management. This active and recognised presence strengthens the contribution of science in key institutions such as the European Union, helping to ensure that scientific recommendations developed at regional level are taken into account in global decision-making.

Funding