Japan’s request to increase catch quotas for Pacific bluefin tuna has failed to win endorsement by the regional fisheries commission for two years in a row, as the United States once again opposed an increase, claiming such a move would be premature. Despite a modest recovery since the fishing quotas was introduced in 2015, the stock of Pacific bluefin tuna remains close to the historic low levels and not much more than 10 percent of its peak.

Behind Japan’s repeated calls for expanding the catch quotas is the plight of domestic fishermen, who complain that the restricted fishing regulations have sharply reduced their income and put their livelihood in danger. However, the region’s stock of large tuna with breeding capability stood at 21,000 tons in 2016 — up from a low of 12,000 tons in 2010 but still a fraction of the peak of 168,000 tons in 1961.

The region’s efforts to raise the stock of bluefin tuna to sustainable levels have just begun. Increasing the catch quotas after only a modest gain might slow the pace of recovery. As the world’s largest consumer of Pacific bluefin tuna, Japan needs to tackle the preservation and recovery of the region’s tuna stock from a medium- to long-term perspective instead of seeking to expand the fishing quotas too quickly.

Bluefin tuna are in high demand in Japan for sashimi and high-grade sushi. However, its stock has been depleted over the years due chiefly to overfishing. In 2015, catch quotas were imposed on each country under the Western and Central Pacific Fisheries Commission (WCPFC), which has set a target of bringing the stock back to 43,000 tons in 2024.

In 2017, WCPFC members also agreed on a mechanism in which the fishing quotas could be adjusted in accordance with the prospect of recovery in the bluefin tuna stock. For the second year in a row, Japan sought a 10 to 20 percent increase in the catch quotas during a meeting of the WCPFC’s 10-member Northern Committee held in the U.S. earlier this month.

But while Japan requested the increase on the basis of research that indicated an increase in the number of young tuna in its neighboring seas over the past two years would make the further recovery in the large tuna stock likely in coming years, it failed to win the required support of all the committee members at the meeting in Portland, Oregon.

The government plans to request expanding the bluefin tuna catch quotas again at next year’s meeting of the WCPFC Northern Committee. But it’s not clear whether Japan can obtain the members’ approval given that the recovery of the Pacific bluefin tuna stock continues to lag behind that of Atlantic bluefin tuna.

In fact, we have a lot to learn from the efforts to recover the stock of Atlantic bluefin tuna, which began much earlier than in the Pacific and have been making steady progress. The bluefin tuna stock in the Atlantic was similarly depleted due to overfishing — sinking to half its peak level at one point. The International Commission for the Conservation of Atlantic Tunas (ICCAT) introduced full-scale catch quotas as early as 1999 to control tuna fishing in the region.

The catch control was further tightened later on as the catch of immature tuna weighing less than 30 kg was banned in principle. The catch quotas were cut down to 12,900 tons in 2011 — far below the overall catch that was once estimated at some 60,000 tons. Fishing countries in the region also tightened controls on the tuna stock at the distribution level by requiring that tuna put on the market be accompanied by catch certification showing and certifying its origin and other data in order to combat illegal and unregulated fishing.

Through such efforts, the Atlantic bluefin tuna stock began to grow, and the catch quotas have been gradually increased since 2013 and are scheduled to reach 36,000 tons in 2020. The example of the Atlantic bluefin tuna shows that catch quotas and strict implementation of regulations can facilitate the recovery of stocks to sustainable levels.

Since the catch quotas were introduced for the Pacific bluefin tuna in 2015, Japan has tightened its control of the domestic tuna fishing industry. The government has set fishing quotas by prefecture and by the size of tuna and their fishing methods, providing for penalties against violators of the quotas.

In 2018, fishermen in some areas had to stop fishing for tuna once they met their quota, while in other areas they didn’t reach their quotas. In order to address the complaints of domestic fishermen and maintain their cooperation with the limits on tuna fishing, the government should explore adjusting the quotas by areas to avert this problem or by promoting the trade of surplus quotas between areas.