Recovery signs for Pacific bluefin tuna have fishers and farmers celebrating

ISSF: 88 percent of global tuna catch from ‘healthy’ stocks, with a notable comeback for Pacific bluefin tuna

In November 2024, a report by the International Seafood Sustainability Foundation (ISSF) revealed that 88 percent of the world’s commercial tuna catch came from stocks deemed “healthy.” It was an improvement from March 2024, when the figure stood at 86 percent. The report also shows that overfished tuna stocks remained steady at 10 percent. While challenges remain, the data signals continued progress in efforts to ensure the long-term health of tuna fisheries worldwide.

Healthy stocks and recovery are key terms for one of the ocean’s fastest and most resilient fish, the Pacific bluefin – and now, the species’ recovery has achieved a major milestone. According to leading researcher and International Scientific Committee (ISC) member Dr. Michel Dreyfus, the Pacific bluefin tuna population increased from a historic low of 2 percent spawning stock biomass in 2010 to 10 percent in 2020 and continues to move in the right direction.

“The Pacific bluefin population declined due to an over-catch of small bluefin, 10 to 15 cm and weighing 2 to 3 kg, by large fleets of artisanal vessels in the western Pacific,” Dreyfus told the Advocate. “These were fishing for a number of species, but they caught lots of small bluefin as well, and often this was bycatch. ISC assessments show that this was happening from the 1990s to 2012, with 80 percent of bluefin tuna caught being less than one-year-old juveniles. Transpacific measures were quickly enforced, including catch limits for Japanese, American and Mexican fleets that have a lot of bluefin fisheries, such as longliners and purse seiners. This resulted in a very fast recovery.”

In addition to catch limits, a system of biannual quotas was established by the Inter-American Tropical Tuna Commission (IATTC) and the Western and Central Pacific Fisheries Commission (WCPFC) to limit pressure on Pacific bluefin stocks and reduce the capture of juveniles, especially by Western Pacific purse seine fisheries. Rules were also drawn up in the eastern Pacific and rebuilding targets were set. The goal was to rebuild to at least 20 percent spawning stock biomass by 2034. However, initial results from an ISC assessment in 2024 showed that by 2022, this number had already reached 23.2 percent.

“Some fisheries have already received raised catch limits based on the results of the 2020 assessment, and this year, there will be a broader increase because of the Pacific bluefin’s new ‘good’ status,” said Dreyfus. “There are also a lot of measures in place so the population doesn’t go down again. We have to take care that there’s no return to overexploited juvenile bluefin of less than one year of age. Everything is in place so the population will continue to be in a safe zone.”

“These results clearly indicate that after years of effort and coordination by the private, public and academic sectors, Pacific bluefin stocks have reached a crucial goal – they no longer hold an overexploited status,” said Rodrigo Armada, director of sustainability at Baja AquaFarms in Ensenada, Mexico. “The Pacific bluefin is an important component in the development of coastal communities, playing a major role in their economic prosperity and growth. Its recovery is much more than a milestone in conservation. It’s a celebration of the proof that collaborative efforts by mankind and nature’s remarkable resilience can, together, stem the tide on dire situations and ensure a prolonged future for our coastal communities.”

Among such collaborative efforts is the role of aquaculture, adds Armada. Baja AquaFarms farms more than half of the Pacific bluefin biomass that is required to meet its market demand. This reduces fishing pressure on wild stocks. It also shares information with the ISC and IATTC for scientific assessments, while observers are invited on board its tuna purse seine vessel at the capture stage of the operation to ensure that quotas and fisheries management practices set by the IATTC are respected.

“A farming operation gives the market a steady supply of Pacific bluefin without the need to fish year-round, thus reducing pressure on wild stocks,” said Armada. “Since 2012, our farm has also been collaborating with Mexican representatives at the IATTC-WCPFC meetings, providing information each year that gives them the exact catch data from the fleet, which helps them fine-tune their population models and have a more precise stock assessment.”

Armada said that aquaculture can also work with scientists through established scientific agreements that allow the sector to have a deeper understanding of the fish’s biology, habitat and behavior.

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“We have established such agreements with leading local universities in marine sciences: the Universidad Autónoma de Baja California (UABC) Ensenada and the Ensenada Center for Scientific Research and Higher Education (CICESE),” he said.

With sustained efforts across the board and steady scientific leadership, Armada is confident that Pacific bluefin tuna populations will continue to recover and show healthy trends. A shared vision of a future in harmony with the ocean is key to ensuring that these trends do not reverse, he said, while viewing challenges under the same lens will enable industry players, regulators, the scientific community and consumers to foster innovation that brings them closer to nature and gives them a deeper understanding of how to meet the world’s growing demand for responsibly raised seafood.

“What we can confidently say now to the public and to people interested in Pacific bluefin is that the measures we are taking, based on science, are good enough to keep the stock in good condition,” said Dreyfus. “Also, when there are catch limit increases, these will be considered scientifically and based on our probabilities that the stock will not again fall to a red point.”