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Overfishing has endangered bluefin tuna — so the US is cracking down

Thanks to heavy fishing and the world's vast appetite for sushi, bluefin tuna populations in the Atlantic and Pacific oceans have been shrinking over the past few decades. And most countries have been slow to do much about it.

But that's starting to change. On December 2, the US National Oceanic and Atmospheric Administration finished and published a major new policy to limit certain types of longline fishing in the Gulf of Mexico — a key spawning ground for the western group of Atlantic bluefin tuna.

The rule will force longline fishermen going after swordfish and yellowfin tuna in the region to use lower-impact methods during the spring spawning season. The hope is that this will reduce the inadvertent killing of bluefin tuna from longlines, which has been a major issue for 50 years. (Under current rules, many of the bluefin just end up getting killed and discarded back into the sea.)

Conservation groups hailed the NOAA rule, which was years in the making, as a huge step. "This change is a major victory, especially because the Gulf is the only known spawning ground for the western Atlantic population of the species," Lee Crockett of the Pew Charitable Trusts wrote. But even with this move, experts have noted that there's more work to be done to halt the rapid decline of bluefin tuna around the world.

The new rules focus on (some) Atlantic bluefin tuna

There are three main species of bluefin tuna in the world: the Pacific, the Atlantic, and the Southern. All three appear to be under heavy strain from fishing. The new NOAA rule focuses mainly on the western subset of Atlantic bluefin tuna.

Atlantic bluefin tuna can range for thousands of miles across the ocean, but there are two distinct groups here — one that spawns in the Gulf of Mexico every spring, and one that spawns in the Mediterranean, near Spain:

atlantic bluefin tuna


According to Pew, the western Atlantic bluefin population has declined 64 percent since 1970. Some of that has been due to fishing of adults off the coast of North America — a trend driven in part by the high demand for sashimi.

Yet there's another ongoing problem in the Gulf of Mexico, where the fish go to spawn every spring. Ever since 1982, fishermen have been prohibited from targeting bluefin tuna in these crucial spawning grounds. But even so, many fishing boats have been using longlines to go after swordfish and yellowfin — and they end up accidentally killing a lot of bluefin tuna in the process.

Longlines can extend for 40 miles, use hundreds of hooks, and often sit in the water for up to 18 hours. Because they're so vast, they tend to catch a lot of things unintentionally — sharks, turtles, bluefin tuna.

Over the years, US regulators have tried to limit the damage from longlines with a variety of regulations on hooks and bait. None of it seemed to do the trick. In 2012, longline fishermen unintentionally caught and killed an estimated 239.5 metric tons of Atlantic bluefin tuna in the Gulf — one-fourth of the total US bluefin catch. (Since there's a limit to how much bluefin the fisherman can bring in, most of that fish is simply discarded overboard, a complete waste.)

So now NOAA is taking an even more drastic step — the agency is restricting the use of surface longlines around the Gulf of Mexico and Cape Hatteras during the April and May spawning season. Instead, fishermen will have to use alternative gear (like green sticks and buoy gear) that tend to be monitored more frequently, so as to minimize unintended catches. And NOAA will tighten the limits on the amount of bluefin tuna that boats can catch inadvertently:

modified gear gulf of mexico


Conservationists had been pushing for moves along these lines for a while — here's a post from January in which Lee Crockett of the Pew Charitable Trusts laid out the rationale behind the idea. (Pew had been pushing for even stronger rules — like restricting longlines over a larger area, or in March as well.)

Yet NOAA also tried to navigate a compromise with fishing groups so as not to shut down fishing for swordfish and yellowfin tuna altogether. The final amendment is here, and ended up being 750 pages long.

But bluefin tuna still face plenty of other threats

This latest NOAA rule only deals with one major subset of Atlantic bluefin tuna — it's a significant move, but hardly the only one under debate. In particular, there are still a few other issues that are being discussed right now:

Overfishing in the eastern Atlantic: The eastern Atlantic bluefin population has fallen by 50 percent since 1970, largely due to heavy fishing in the Mediterranean and eastern Atlantic. And regulators have gone back and forth on how tightly to curtail activity.

A few years ago, after decades of lax quotas, the International Commission for the Conservation of Atlantic Tunas (ICCAT) decided to impose much stricter overall limits on catches and started cracking down on illegal fishing. Those restrictions seemed to have an impact: In 2012 and 2013, the population of eastern Atlantic bluefin tuna did appear to rebound slightly.

But this past November, ICCAT decided to loosen the restrictions and increase the amount of Atlantic bluefin tuna that fishermen were allowed to catch. That alarmed conservationists, who argued that tuna populations still need more time to rebound — and that stricter electronic tracking mechanisms were needed to thwart illegal fishing. (It's worth noting that there are plenty of academic disputes about the optimum levels for quotas.)

Overfishing in the Pacific: Meanwhile, the situation is even more dire for Pacific bluefin tuna. An assessment published in April 2014 estimated that bluefin tuna numbers in the northern Pacific Ocean were now 96 percent below their historic baseline.

Pacific bluefin tuna, which spawn off the coast of China and then swim as far as Mexico, are being fished heavily at all stages of their lives. About 80 percent of Pacific bluefin tuna are caught for use in sushi restaurants in Japan, where a single large fish can fetch tens of thousands of dollars on the open market:


(Pew Charitable Trusts)

Conservation groups have called for several things to protect the Pacific bluefin: harder limits on overall catches in the Pacific Ocean and a minimum size limit on catches to protect juveniles.

Back in September, the international commission that governs the west and central Pacific met in Fukuoka, Japan and agreed to limit juvenile catches to 50 percent below 2002-2004 levels (which is roughly how much was caught last year, so this wasn't a huge move). The commission also called for a rebuilding plan that would only slightly increase the size of the tuna population — from 4 percent of historical levels up to 6.9 percent.

Meanwhile, the commission that governs the eastern Pacific has been postponing any moves to regulate bluefin tuna fishing for now. Any restrictions are likely to be contentious, as they'd force fishermen to take a short-term hit — particularly in Japan.

Further reading: How the US stopped its fisheries from collapsing.

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