Atlantic bluefin tuna will shift north as ocean warming accelerates.
- An international study led by researchers at AZTI examines how ocean warming is pushing Atlantic bluefin tuna northwards, while ecologically critical areas such as the Mediterranean Sea and the Gulf of Mexico could become increasingly unsuitable for spawning.
- Published in Fish and Fisheries, the research identifies emerging suitable habitats and high-latitude “refugia zones”, and highlights the need to incorporate climate-change impacts into fisheries management to safeguard the sustainability of one of the world’s most economically valuable marine species.
Atlantic bluefin tuna (Thunnus thynnus), one of the world’s most iconic and highly prized marine species, is changing its distribution in direct response to climate change. An international scientific study concludes that rising ocean temperatures will alter—throughout the 21st century—the areas where this species can feed, spawn and be harvested.
The study, Navigating Future Waters: The Resilience of the Atlantic Bluefin Tuna Under Climate Change, published in Fish and Fisheries, shows that as the ocean warms, bluefin tuna are likely to shift progressively northwards in search of cooler, more productive waters. This shift would mean habitat losses in tropical and temperate regions, alongside gains in favourable conditions further north—such as northern Europe, waters around Greenland, and the Northeast Atlantic.
Another projection indicates that the two main spawning grounds for bluefin tuna—the Mediterranean Sea and the Gulf of Mexico—could become far less suitable for adult fish. Under the most pessimistic greenhouse-gas emissions scenario, habitat suitability in the Mediterranean could decline by 27%, while suitability in the Gulf of Mexico could drop by as much as 70%, jeopardising the species’ long-term reproductive success.
“Bluefin tuna show a strong capacity to adapt, but our projections indicate that climate change is altering the balance between feeding areas, spawning grounds and fishing activity,” explains Maite Erauskin-Extramiana, AZTI researcher and lead author of the study. “That is why it is essential to progressively integrate projected climate-change impacts into management systems, so we can anticipate change and manage resources more efficiently and sustainably.”
New refugia and emerging challenges
The work also analyses how the distribution of key prey species for bluefin tuna—such as sardine, mackerel and squid—is expected to evolve. These prey species show a similar shift towards higher latitudes, creating new overlap areas between tuna and their main prey, particularly in boreal regions. These areas could act as “climate refugia” or future hotspots of especially favourable conditions.
“Climate change is affecting not only ecosystems, but also how we manage marine resources,” says Erauskin-Extramiana. “Anticipating these shifts is key to protecting both biodiversity and the livelihoods that depend on it.”
Science to support climate-adaptive management
The study is based on advanced models combining environmental data, bluefin tuna occurrences, prey distribution and fishing activity, and projects multiple climate scenarios through to the end of the century. The findings underscore the urgent need for flexible, climate-adaptive fisheries management—capable of responding to species that no longer conform to traditional boundaries.
This study was conducted with support from Spain’s Ministry of Science and Innovation and the European projects FutureMares, SusTunTech, Mission Atlantic, Biodiversa+ and SOMBEE.
Scientific article
Erauskin-Extramiana, M., Valle, M., Cruz, L., Muhling, B., Fernandes-Salvador, J. A., Pozo Buil, M., Ortuño Crespo, G., Brodie, S., Hazen, E. L., Bograd, S. J., Arrizabalaga, H., Merino, G., & Lezama-Ochoa, N. (2026). Navigating future waters: The resilience of the Atlantic bluefin tuna under climate change. Fish and Fisheries. Advance online publication. https://doi.org/10.1111/faf.70061
About AZTI
AZTI (www.azti.es) is a scientific and technological centre specialising in the marine environment and food, developing high-impact transformation projects with organisations aligned with the United Nations 2030 Sustainable Development Goals (SDGs). Its mission is to drive positive change for the future through cutting-edge, value-added products and technologies grounded in robust science and research—contributing to a healthy, sustainable and inclusive society.
AZTI brings more than 40 years of experience, a presence in 45 countries, three sites in the Basque Country, and a team of more than 280 full-time professionals. Its track record is supported by over 1,900 indexed publications, and its excellence is underpinned by its research staff—69% of whom hold PhDs and 57% of whom are women.
AZTI is a member of the Basque Research and Technology Alliance (BRTA), an alliance made up of four cooperative research centres and 12 technology centres. BRTA aims to foster collaboration among its member organisations, strengthen the conditions for generating and transferring knowledge to companies to enhance competitiveness, energise the industrial fabric, and project Basque scientific-technological capabilities internationally.
Image: AZTI