TEMPLADOS VarBi

Context

Basque temperate tuna fisheries, particularly albacore (Thunnus alalunga) and Atlantic bluefin tuna (Thunnus thynnus), are essential to the Basque coastal fleet, both in terms of tradition and economic value. Ports in the Basque Country account for nearly 50% of Spain’s albacore catches and around 30% of international catches in the North Atlantic, highlighting the importance of this resource.

Monitoring these fisheries has been essential for decades to ensure their sustainability. The International Commission for the Conservation of Atlantic Tunas (ICCAT), through its Standing Committee on Research and Statistics (SCRS), assesses the status of stocks each year and proposes management measures based on scientific evidence. Within this framework, data provided by the Basque fleet —particularly time series of abundance indices (CPUE)— are fundamental, as they represent one of the main sources of information used to assess albacore and Atlantic bluefin tuna populations.

The introduction of harvest control rules and long-term management strategies for both species has brought about a paradigm shift in international fisheries governance. This creates a need to continuously update available analyses and data in order to adapt management decisions to the actual status of the stocks and ensure the sustainability of both the resource and the fishing sector.

Objectives

The aim of this project is to improve the management of temperate tuna species. To achieve this, AZTI will carry out the following activities:

• Active participation in ICCAT’s scientific committee.
• Continuous provision of information to public authorities and the fishing sector on the status of the fisheries.
• Studies on tuna fisheries and biology to improve understanding of the dynamics of these populations.
• Coordination and chairing of the albacore working group.
• Analysis of CPUE for temperate tuna species in the Bay of Biscay.
• Evaluation of management strategies for albacore.
• Identification of exceptional circumstances that may affect the application of the TAC.
• Contribution to the development of new Atlantic bluefin tuna management advice for the 2026–2028 period.

Expected impact

The project will improve the quality and availability of scientific data for assessing albacore and Atlantic bluefin tuna stocks, helping to ensure that management decisions are based on robust and up-to-date indicators.

Updating abundance time series for the Basque fleet will be key to verifying the status of these resources and ensuring that the TACs and management strategies adopted by ICCAT reflect the actual condition of the populations. In this way, the project contributes to the sustainability of temperate tuna species, an essential resource for the Basque coastal fleet.

The development of management advice is particularly important for this fleet, which catches a significant proportion of the albacore TAC and benefits from a derogation under current regulations concerning minimum sizes for Atlantic bluefin tuna. Direct involvement in defining these measures therefore helps ensure that the specific characteristics of the Basque fleet are represented in decision-making.

In addition, AZTI’s leadership of the albacore working group places the organisation in a position of responsibility and international recognition in tuna management. The scientific contributions generated through the project —working documents, publications and presentations at ICCAT and international scientific forums— consolidate AZTI’s research excellence and strengthen its role as a reference laboratory in this field.

Funding