The Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC) – two regional fishery management organizations (RFMOs) that set rules for tuna fishing in the Pacific Ocean – have rejected a Japanese proposal to speed up catch limit increases of Pacific bluefin tuna.
The Japanese delegation that attended a meeting of the Joint Working Group on Pacific Bluefin Tuna from 3 to 5 July in Fukuoka, Japan, requested hastened catch limit increases in response to the species’ rapidly growing stock, referencing data that buttresses their claim.
A report by the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean states that the initial target – jointly adopted by the WCPFC and the IATTC – of rebuilding Pacific bluefin tuna stock back up from its historically low spawning stock biomass (SSB) in 2010 was achieved in 2019 – five years earlier than expected.
A second target of limiting fishing mortality to 20 percent of the potential SSB has a 60 percent probability of success in 2023 – six years earlier than originally estimated.
“[The] WCPFC and IATTC increased the catch limits of large Pacific bluefin (30 kilograms or larger) by 15 percent since 2022, but this increase has apparently fallen behind the rapid increase of the PBF stock,” the delegation’s proposal states.
The delegation attributed the rapid increase in the population of bluefin to stricter limits imposed on retaining juveniles, which allows more fish to reach spawning size.
It also noted that as bluefin populations increase, the requirement to release bycatch bluefin from nets before hauling them in results in the escape of target fish, placing a heavy burden on fishermen – particularly those operating set-nets.
“In usual cases, fishermen release Pacific bluefin by sagging or opening a part of [their] set-net, which results in the escape of other fish species, causing great economic losses,” the report said. “Such releases are becoming more frequent all over Japan due to the significant gap between the growing stock level and the fixed catch limits. In some set net sites in Japan, fishermen released Pacific bluefin from their nets in more than half of their annual operations.”
Both longline and artisanal troll fishery vessels must shift target species after reaching their Pacific bluefin catch limit, according to the proposal’s outline of the issue. Pacific bluefin is, thus, a “choke species” that prevents fishing for other species for fear of exceeding catch limits through accidental bycatch.
Some experts said that, although the RFMOs rejected the proposal this time, there may be hope for accelerated catch limit increases at future meetings.
“This year’s meeting did not change the current catch limit, but there will be a stock assessment next year,” Shana Miller, project director of international fisheries conservation for the Ocean Foundation, told SeafoodSource following the meeting. “Depending on the outcome of the assessment, catch limits may be increased for 2025, especially if the second rebuilding target is projected to have been met.”
However, Miller said that it would be premature to significantly increase the catch limit next year, since there is always some uncertainty in stock assessments. She added that a long-term harvest strategy that could interfere with current catch increase proposals is planned for adoption in 2025.
The working group, while rejecting the quickened catch increase proposal, managed to pass some measures during the meeting, including setting reference points for a management strategy evaluation (MSE) – a computer model that tests harvest control rules (HCRs) under a wide range of conditions – and advancing an electronic catch monitoring system.
Reference points typically include both a target and a limit and often rely on data concerning population size or fishing mortality. Miller said reference points considering both data points are most effective.
“The final list of candidate reference points agreed this week, unfortunately, does not include a stock size-based target reference point,” Miller said. “However, the agreed workplan does now require an evaluation of harvest strategy performance relative to a population level associated with the target fishing mortality, so this could accomplish the same goal.”
The meeting also discussed funding and administration for an electronic catch documentation system called the Pacific Bluefin Tuna Catch Documentation (ePBCD) system. Members agreed to a provisional path forward to get the system online within the next few years.
“We applaud this effort and encourage development and application of similar catch documentation systems for other key Pacific stocks,” Miller said.
Following the Joint Working Group meeting, the 19th Regular Session of the Northern Committee of the WCPFC also occurred in Fukuoka from 6 to 7 July, where the committee helped advance a harvest strategy for albacore tuna within the WCPFC’s boundaries.
Miller said that the biggest wins from the two meetings came from the latter gathering, specifically regarding climate change and albacore tuna management.
“For the first time, the Northern Committee discussed the potential impacts of climate change on Pacific tuna fisheries and the need to start exploring management approaches that can adapt to a changing ocean,” said Miller. “We look forward to engaging in this important effort, which should include incorporating climate considerations into the ongoing development of harvest strategies for North Pacific stocks since harvest strategies already offer an adaptive management approach.”
Regarding albacore, Grantly Galland, project director for international fisheries at The Pew Charitable Trusts, said the meeting elicited significant progress – but that further actions are necessary to ensure the changes stick.
“Today, the WCPFC Northern Committee took a significant step toward comprehensive, Pacific-wide management for North Pacific albacore tuna. Adopting a science-based harvest strategy that relies on data to automatically set catch limits shows a serious commitment to long-term sustainability,” Galland said. “Now, because North Pacific albacore is jointly managed with the IATTC in the Eastern Pacific, success still hinges on agreement by IATTC managers, who meet in August. Without a Pacific-wide harvest strategy, the good work by WCPFC risks being ineffective.”
Photo courtesy of Carl.Salisbury/Shutterstock
