The Scientific Committee of the Indian Ocean Tuna Commission (IOTC) recently published its latest assessment of the stocks overseen by the regional fishery management organization (RFMO), issuing a “green” rating for the yellowfin tuna stock – which has for nearly a decade been considered overfished.
The yellowfin stock has long been the subject of scrutiny by environmental organizations and NGOs, who have criticized the IOTC for failing to address overfishing. A report released by the IOTC Scientific Committee in 2022, the first assessment since 2018, found catch of the species would need to be reduced by 30 percent to bring it back in line with scientific advice.
The yellowfin stock was first declared overfished in 2015, and since that time, the stock has continued to be overfished.
Despite that continued overfishing, the latest report from the IOTC Scientific Committee gave the stock a green rating, using a series of revisions based on a model developed in 2021.
“These revisions addressed many of the recommendations of the independent review of the yellowfin stock assessment carried out in 2023,” the report said.
According to the new assessment, IOTC yellowfin got a green rating, and on the weight of evidence available to the committee, the stock was “determined to be not-overfished and non-subject to overfishing,” the committee report said.
While the new assessment is good news for the yellowfin tuna stock, Pew Charitable Trusts International Fisheries Senior Officer Glen Holmes said it shouldn’t be taken as a sign to abandon any work on its sustainability.
“We welcome the new stock assessment that addresses some of the complexities around yellowfin and indicates a healthier status. However, significant uncertainties remain and the IOTC should continue to treat this stock with caution,” Holmes said.
Holmes told SeafoodSource that a stock shifting from overfished to being considered healthy isn’t unheard of. Pacific bigeye tuna was at one point rated differently until improved knowledge about the growth of the species was introduced.
“It’s also possible that shifting environmental factors have played a role, but at this stage, that is just a theory,” Holmes said.
The story behind the sudden shift in yellowfin tuna’s status, he said, is complicated and related to shifts in both science and policy.
“There was no explicit total allowable catch recommendation previously from the scientific committee, but the maximum sustainable yield was estimated to be 349,000 metric tons,” Holmes said. “The stock assessment that determined this level was also externally peer reviewed, and the reviewers highlighted several issues that needed improvement.”
The latest stock assessment took some of those recommendations into account and, according to Holmes, represents an improved understanding of yellowfin stock dynamics and a more accurate picture of the overall status of the stock.
“However, there are still ...
