The Beacon

Oceana Magazine: Tuna in Trouble

A bluefin tuna (Thunnus thynnus) in the Mediterranean. (Photo: Oceana / Keith Ellenbogen)

The Atlantic bluefin tuna made an incredible recovery after decades of overfishing. Now, seismic airgun testing in the Mediterranean Sea threatens to unravel progress that was made for this super predator. This article was originally published in the summer 2014 issue of Oceana magazine, and the full excerpt can be viewed here.

Tuna in Trouble

Picture an ocean super-predator. It’s one of the largest and fastest fish in the entire ocean — growing up to 8.5 feet long and nearly 900 pounds, but still capable of charging through the water at more than 45 miles per hour in short bursts. This fish has glistening, silver-blue scales, sickle-like fins, a row of wicked-looking yellow spines along its back, and rows of sharp teeth. But this beautiful and formidable predator is not a shark — it’s a tuna.

The Atlantic bluefin tuna is deceptively fearsome — most culinary fans of tuna don’t realize that the fish on their plate, Thunnus thynnus, is a highly evolved ocean predator. But unfortunately for bluefin tuna, their size and muscle power make them a highly valuable commercial species. During the past three decades, the Atlantic bluefins population fell dramatically due to overfishing, but Oceana and our allies were successful in halting the decline. Now, just as the tuna are starting to recover, oil and gas exploration in the Mediterranean could jeopardize their recovery.

“If we allow oil and gas exploration in the Spanish Mediterranean, it could undo all of our hard work to help this species recover,” says Xavier Pastor, Oceana senior vice president and executive director for Europe.

Atlantic bluefin tuna are loosely divided into eastern and western populations: the two stocks mingle in the open ocean, but they return to opposite ends of the compass to breed. Eastern bluefins breed in the Mediterranean Sea, while the westerns breed in the Gulf of Mexico.

Both populations collapsed by the early 1980s, after an explosion in the industrial fishing fleet and better gear allowed fishermen to travel farther into the ocean in search of tuna. In 1998 the International Commission for the Conservation of Atlantic Tunas (ICCAT) set quotas to attempt to halt the decline, but the numbers were still far higher than scientists advised. Scientists estimate that between 2005 and 2011, the actual bluefin tuna catch exceeded the total allowable quota by 44 percent, according to a 2013 study in PLOS ONE.

Then in October of 2012, an ICCAT assessment revealed the first signs of recovery for both eastern and western bluefin. The commercial fishing industry clamored to raise the quotas, says Pastor, but Oceana and our allies insisted that doing so would completely undermine further recovery. Since then, Oceana has campaigned to keep bluefin tuna quotas steady in the face of constant pressure from the fishing industry. Yet overfishing isn’t the only thing threatening eastern bluefins.

Spain’s Balearic Islands are known for their tourist-filled beaches and blue waters, but they are also the most critical breeding ground for eastern bluefin. Each summer, tens of thousands of tuna migrate to the area’s warm waters to spawn. Yet these breeding grounds could soon be inundated with the deafening blasts of seismic airguns.

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