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Overfishing is wiping out bluefin tuna — so the US is cracking down

A load of bluefin tuna is pictured in a boat in the port of Sete on the Mediterranean coast, southern France, on May 17, 2014.
A load of bluefin tuna is pictured in a boat in the port of Sete on the Mediterranean coast, southern France, on May 17, 2014.
(PASCAL GUYOT/AFP/Getty Images)

Is there still time to prevent bluefin tuna from vanishing?

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

But that's gradually starting to change. Last week, the US National Oceanic and Atmospheric Administration finalized 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 move 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 big step. "This historic action will help western Atlantic bluefin tuna rebuild to healthy levels," Lee Crockett of the Pew Charitable Trusts said in a statement. 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 are in serious trouble from overfishing. 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

(Smithsonian)

All told, the western Atlantic bluefin population has plummeted 64 percent since 1970. Much of that has been due to overfishing of adults off the coast of North America — a trend driven in part by the high demand for sashimi.

But 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

(NOAA)

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 the bluefin tuna still faces 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 rampant overfishing in the Mediterranean and eastern Atlantic. Just recently, 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 has cracked down on illegal fishing.

It remains to be seen if these new restrictions will work as intended. On the one hand: In 2012, the population of eastern Atlantic bluefin tuna did appear to rebound slightly. But illegal fishing is still ubiquitous, particularly in southern Europe — and that may undermine these stricter quotas.

For the time being, ICCAT is planning to keep its current quotas in place, though some conservation groups have called on the organization to go even further and implement electronic tracking mechanisms to thwart illegal fishing. (It's also worth noting that there are plenty of academic disputes about the optimum levels for quotas.)

Overfishing in the Pacific: Meanwhile, the situation is arguably 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 livesAbout 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:

Tuna-pacific-tuna-migration-776-lw

(Pew Charitable Trusts)

Conservation groups have called for two 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.

But it remains to be seen what sort of policies will emerge. Any restrictions are likely to be contentious, as they'd force fishermen to take a short-term hit — particularly in Japan. And, so far, regulators have been reluctant to take any drastic steps along those lines.

This week, the international commission that governs the west and central Pacific is meeting in Fukuoka, Japan to discuss management policies. Meanwhile, the commission that governs the eastern Pacific has been postponing any moves to regulate bluefin tuna fishing until at least the fall.

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

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