Scientists Confirm Pacific Bluefin Tuna Is on the Brink

The latest scientific assessment of Pacific bluefin tuna is out, and it confirms that this overexploited, highly valued resource has been ravaged by rampant overfishing.

Scientists with the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean, or ISC, published their findings online on April 18. The report finds the population of Pacific bluefin tuna remains barely 4 percent of its historic size before fishing began, a dramatic decline equivalent to the entire U.S. population dropping to that of Pennsylvania.

This is a clear example of what happens when fishing nations turn a blind eye to decades of severe overfishing,” said Amanda Nickson, director of global tuna conservation for The Pew Charitable Trusts. “The Pacific bluefin population has literally been decimated. The solution is clear—we need a precautionary quota to limit overall catch and a minimum size limit to protect juveniles. These steps should be implemented immediately as part of a robust rebuilding plan to ensure this species can pull through and recover.”

Pew continues to advocate for implementation of science-based catch limits on both sides of the Pacific to help reverse the bluefin's decline. A minimum size limit for each fish is also critical for protecting juveniles. This is the chief management recommendation of ISC scientists. Prohibiting the catch of bluefin that weigh less than 20 kilograms (44 pounds) would protect fish age 2 and younger and lead to significant population gains in just a few years.

Are fishing nations ready to act?

In the latest assessment, scientists looked at ways the population might be rebuilt. Only one scenario showed signs it might work—reducing the catch of juveniles by 50 percent in the western and central Pacific and setting a hard catch limit for bluefin of 2,750 metric tons (6.1 million pounds) a year in the eastern Pacific. However, even these measures might not lead to a population that would be considered healthy and rebuilt.

It is a positive sign that Japan, which catches the bulk of Pacific bluefin tuna, is now publicly committing to bring its fishing in line with what scientific advice tells us is the bare minimum to reverse the decline of Pacific bluefin tuna,” Nickson said. “Still, we need a commitment from all fishing nations across the Pacific to take collective action on a scientifically based rebuilding plan that restores the population to at least 25 percent of its original size within 10 years.”

This year, the regional fisheries management organizations that regulate Pacific bluefin tuna will take up these issues. Japan accounts for a majority of the Pacific bluefin caught each year, with Mexico, South Korea, Chinese Taipei, and the United States netting significant percentages as well. These member states of the Inter-American Tropical Tuna Commission and the Western and Central Pacific Fisheries Commission must come to consensus and act on the scientific advice by implementing catch limits and restricting fishing of the smallest and youngest fish.

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