Funding
Eusko Jaurlaritza – Basque Government through the European Maritime, Fisheries and Aquaculture Fund
Changes in the accessibility and availability of mackerel and anchovy: technical and strategic adaptations
The project builds on the SALPAS project (2023–2024) and responds to concerns raised by the fishing sector regarding changes in the behaviour and availability of anchovy and mackerel in the Bay of Biscay. Since 2018, small-scale fisheries in particular have reported increasing difficulties in catching mackerel, linked to a deeper distribution of the species during the fishing season, while trawl and purse seine fleets have largely maintained their catch capacity.
These changes have been linked to key environmental and ecological drivers, including the increase in gelatinous organisms (salps, locally known as “zikiña”), rising predator abundance such as bluefin tuna, and increasing water temperatures. Similar trends have been observed in anchovy, which appears to occupy deeper layers and avoid areas with high concentrations of gelatinous organisms—findings supported by scientific surveys.
The SALPAS project addressed this issue through a multidisciplinary approach, integrating environmental data, scientific surveys and sector knowledge, and identified significant changes in the pelagic ecosystem, including deeper anchovy shoals, marine heatwave-related increases in gelatinous organisms, and greater predation pressure on mackerel.
This new project aims to deepen understanding of these patterns, focusing on changes in the vertical and spatial distribution of anchovy and mackerel, with the goal of generating applied knowledge to support sector adaptation and ensure sustainable exploitation.
The overall objective is to provide scientific knowledge and projections to support adaptation of the fishing sector, ensuring the sustainable exploitation of mackerel and anchovy under changing environmental conditions.
Specific objectives
2025
• Investigate in greater depth the distribution and composition of “zikiña” as a potential driver of anchovy vertical distribution.
• Analyse changes in mackerel vertical distribution and develop models linking anchovy and mackerel distribution to environmental variables.
• Evaluate changes in mackerel availability for the fleet in relation to stock biomass and fishing mortality in northern areas.
• Propose technological and strategic adaptations for efficient and sustainable fishing.
2026
• Analyse variability in adult availability at higher latitudes and in the Cantabrian Sea using biomass indices from acoustic surveys.
• Evaluate shifts in the centre of gravity of mackerel egg aggregations during spawning as an indicator of behavioural changes.
• Analyse the effects of juvenile distribution changes associated with “zikiña” on adult anchovy in spring.
The mackerel and anchovy fishing seasons are a key source of income for artisanal and purse seine fleets, and changes in availability have a direct economic impact on the sector.
This project will identify the causes and magnitude of distributional changes and anticipate future scenarios, providing a solid scientific basis for action. Based on this knowledge, mitigation and adaptation measures will be proposed to maintain fleet efficiency and ensure that exploitation remains sustainable.
Eusko Jaurlaritza – Basque Government through the European Maritime, Fisheries and Aquaculture Fund
Sectors: Fisheries and aquaculture sector
Research lines: Climate change, Efficient, sustainable fisheries and aquaculture
Research sublines: Observation and impact of climate change, Sustainable fishery management
