Kindai bluefin tuna, farmed sustainably, available in Philadelphia

It's a chilly 35 degrees in the fish-cutting room at the new state-of-the-art headquarters of Samuels & Son Seafood in South Philadelphia's wholesale fish market.

Two workers carefully lift the beautiful, shiny, silvery-blue, torpedo-shaped, 196-pound tuna from its coffin-shaped foam air-freight container onto the worktable.

This ultra-luxury bluefin tuna called Kindai is flown in weekly from Japan for Samuels to sell to chefs who pay about $40 to $50 per pound to serve it, usually as sushi, ceviche, or crudo.

One of the company's top cutters, Pham Mung, carefully dissects the fish into custom-cut sections, with the super-fatty bottom loin, or otoro, the most expensive. The silky, buttery, luminous flesh is deep red, almost purple, with a beautiful texture and a pure and vivid taste.

But this bluefin tuna was not caught in the open sea; it began its life as an egg in a lab at a Japanese university and is now being offered at some of the finest local restaurants serving sushi and crudo, including Morimoto, Zama, and Vetri in Center City and Fuji in Haddonfield.

Since the 1970s, as sushi has grown into a worldwide phenomenon, demand has skyrocketed for bluefin, a fish many sushi aficionados consider piscine royalty. As a result, "an estimated 80 percent of the world's bluefin tuna stocks have been fished out."

"All populations of bluefin tuna are being caught faster than they can reproduce," according to Monterey Bay Aquarium's Seafood Watch.

To make matters worse, the BP drilling rig disaster gushed oil into the only bluefin tuna spawning ground in the Americas, as the western Atlantic population of bluefin were about to spawn in the Gulf of Mexico.

Samuels, the region's largest wholesale seafood distributor, until recently had been buying three to four wild bluefin weekly, and only fish caught responsibly with rod and reel. But in a further commitment to sustainability, Samuels recently made the difficult decision to stop selling wild bluefin tuna.

"We recognize there is a significant problem with bluefin tuna due to overharvesting over the last 30 years," said Joseph Lasprogata, director of purchasing at Samuels. "We will no longer handle wild northern bluefin tuna."

"By doing this, we hope to bring attention to this important issue. When stocks have reached a healthy level, we'll carry bluefin once more."

Instead, Samuels has become the regional supplier of Kindai tuna, born and bred at Japan's Kinki University's Fisheries Laboratories, as one way to sustain the bluefin, at least for top restaurants.

Research began there in 1970, and it took until 2002 for scientists to succeed in raising bluefin from egg to full-grown fish. Kindai is a nickname for Kinki University, which has pioneered what it calls a "blue revolution" - developing marine resources to help feed the world. Like a Gucci bag, each Kindai tuna comes with a label of authenticity. The supply is quite limited - only a few hundred fish are harvested each year. Just three reach the U.S. each week, two of them headed for Samuels, which sells the fish to top restaurants in New York, Philadelphia, and Washington.

Kindai tuna are farmed, rather than ranched: raised to maturity from wild bluefin eggs, which ensures genetic diversity. Mediterranean, South Australian, and Mexican tuna ranchers capture juvenile fish, raise them in net pens, and often ship them to market before they are mature enough to reproduce. Critics say ranching doesn't help rebuild stocks, though the higher prices they fetch help fishermen.

Because tuna never stop moving (up to 40 m.p.h.), they eat enormous amounts. It takes about 25 pounds for a ranched tuna to gain 1 pound; for Kindai, the ratio is better, but still high: about 12 to 1, though scientists are working to bring the feed conversion ratio down.

The farmed tuna eat mainly squid, mackerel, and sardines that have been frozen to prevent waste and kill bacteria. Because Kindai are smaller and eat smaller fish, which contain less mercury, they are also lower in mercury than wild bluefin.

"These Japanese scientists want to do the right thing for this majestic animal," said Anthony D'Angelo, head of product development at Samuels. "The fish eat their natural diet, they are not crammed into small pens. . . . Their true value is the future of our fisheries."

Chef Hiroyuki "Zama" Tanaka, of Zama Restaurant, realized he needed to take a stand on the bluefin tuna: "I am so happy that I deal with Kindai tuna because it is sustainable, consistent, and clean. Every time I order the fish it's the same."

Initially, he listed the Kindai as bluefin tuna on his menu and it sold slowly. When he changed the wording to "100 percent sustainable," sales took off.

"I've had a really great reaction from customers, both for sustainability and taste. I think that in five, 10, or 15 years people will say, 'Wow, you really used to eat wild bluefin!' Just like salmon, we'll see that farmed bluefin will become the standard."

Marc Vetri, chef/owner of Vetri, Osteria, and Amis, said he had been using Kindai more and more as part of his tasting menus at Vetri. "I love it! It's ridiculous how good it is," he said. "And it's a step in the right direction for bluefin tuna."