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Scientists eye new framework for bigeye tuna catch limits for territories

Western Pacific Regional Fishery Management Council logo
(Source: WPRFMC media release)

Pago Pago, AMERICAN SAMOA — The Western Pacific Regional Fishery Management Council’s Scientific and Statistical Committee (SSC) this week reviewed a framework to establish multi-year allocation limits for bigeye tuna from American Samoa, Guam, and the Commonwealth of the Northern Mariana Islands (CNMI). The new framework may remove requirements for annual catch limits in the territories from the Council’s Pelagic Fishery Ecosystem Plan. 

The Western and Central Pacific Fisheries Commission (WPCFC), that manages the tuna stock internationally, does not require catch limits for Small Island Developing States and Participating Territories. However, the Council conservatively recommended catch limits for the territories when the WCPO bigeye tuna stock was considered to be experiencing overfishing in 2014. New data revealed in 2017 the stock was not overfished, nor experiencing overfishing. 

The Council is considering taking action to specify multi-year territorial bigeye tuna catch and/or allocation limits at its meeting during the last week of March. The SSC determined that the bigeye tuna stock was healthy and any potential impacts of the Hawai‘i-based U.S. longline fishery would be minimal.

 “We can all agree, based on the science available, that the options presented to the Council do not pose any significant conservation risk to tuna stocks,” said Steve Martell, SSC member.

SSC members plan to develop alternatives to manage the U.S. longline fleet before the WCPFC hosts its longline management workshops this summer.


The (SSC) also reviewed a 2023 study that found the Phoenix Islands Protected Area (PIPA) and other large oceanic no-take marine protected areas (MPAs) do not have discernible conservation benefits for Pacific skipjack and bigeye tuna.

The paper published in Frontiers in Marine Science was led by world-renowned tuna expert Dr. John Hampton of the Pacific Community (SPC) and a team of tuna scientists and oceanographers. The authors evaluated the estimated population and fishery changes for these two commercially important tunas in the PIPA and a series of large hypothetical MPAs, making up approximately 33% of the Western and Central Pacific Ocean (WCPO).

 “Skipjack and bigeye tuna have a wide distribution in tropical and sub-tropical waters of the Pacific, and are capable of spawning anywhere the water temperature is greater than about 25 °C [77°F],” said Hampton. “Their larvae drift in the surface water currents, and as they grow, they are able to move widely throughout the region. So closing off one part of the area does not offer much, if any, protection to species like this.” He added, “When areas like the PIPA are closed to fishing, we tend to see the vessels that would have fished there simply move their activities to adjacent areas, which again limits their conservation effectiveness.”

SSC member Ray Hilborn also presented research findings suggesting the 2016 expansion of the Papahānaumokuākea Marine National Monument (PMNM) in the Northwestern Hawaiian Islands did not lead to significant localized increases in tuna. Hilborn’s analyses counter claims made in a study published in Science in October 2022. The claim was based on higher tuna catch rates outside the expansion area after 2016. Hilborn revealed catch rates were already higher in areas immediately outside the new monument border prior to its designation. 

The SSC concurred with the two scientists’ findings.