A Tale of Three Tuna
The future of sushi is in your hands

By Trevor Corson

Imagine sitting down at your favorite sushi bar. The chef reaches across the fish case and serves you three pieces of sushi. “Bluefin tuna,” he says with a grin. The pink flesh of bluefin, marbled with fat, is considered by many connoisseurs to be the ultimate sushi delight.

These three pieces of bluefin look exactly alike, but the chef points at them and frowns. “Each of these tuna is different,” he says. His gaze sweeps across the fish in his case. “Depending on what you eat,” he continues, “you can save the future of sushi ... or destroy it. Your choice.”

Most of us don’t realize that we face such stark choices at the sushi bar, and most sushi chefs don’t tell us these things. But industry and technology have, in fact, brought three radically different types of bluefin tuna to our tables. Which of these three types of bluefin we eat—and more importantly, how much of them we eat—could determine whether sushi as we know it survives.

Let’s investigate these three types of bluefin tuna. The first piece is “wild-caught.” This fish was harvested the old-fashioned way, from the open ocean by a fisherman. It might have been caught off Boston or Vietnam or in the Mediterranean, flown on ice to Tokyo for grading and pricing, and then flown to New York, L.A. or Kansas City.

But fishermen have caught so many wild bluefin that the species is in terrible danger. Scientists estimate that in some areas of the globe, 90 percent of bluefin have been wiped out. At an average sushi restaurant nowadays, it’s becoming less likely that you’ll encounter a wild-caught bluefin at all.

This brings us to the second piece of sushi. This bluefin tuna would be labeled “farmed.” Sounds promising, right? Trouble is, this second fish—like 99 percent of bluefin that are labeled “farmed”—wasn’t farmed at all. It was actually “ranched,” a questionable technique that tuna entrepreneurs pioneered in the early 1990s.

Just like the first of our three tuna, this ranched variety began its life in the open ocean. Fishermen trapped a school of these fish in a huge net, but instead of killing them, they towed the net to a holding pen near shore. Then they fed the tuna a rich diet of frozen fish for a few months, until the bluefin had grown big and fat.

Unlike true farming, ranching does nothing to help stocks of wild bluefin. If anything, it worsens their plight, since the fish are often trapped at a younger age, before they’ve had a chance to do much mating. Ranching mostly just helps the ranchers, by reducing risk and generating a steady supply of pricey, pre-fattened fish.

And now to our third and final piece of sushi. It looks deceptively like the other two pieces, but it represents a new development in tuna science and technology.

Until recently, no one had actually managed to cultivate bluefin in captivity. The fish are edgy, enormous, and very fast swimmers. But after several decades of experimentation, biologists at Kinki University in Japan finally succeeded a few years ago. They sold the first of their true farm-raised bluefin to restaurants in Japan in 2004.

In the past few months, a very small number of sushi restaurants in the U.S. have begun to feature these fish as well, branded as “Kindai Tuna.” Each of these bluefin arrives from Japan with a certificate stating that it was farmed in a healthy and environmentally friendly way.

Unfortunately, when it comes to most types of fish, farming has often caused as many problems as it has solved—pollution, genetic alterations, and health risks, not to mention flesh that tastes bland. It remains to be seen whether true farmed bluefin turn out to be as sustainable and friendly as the farmers claim.

So which of the three pieces of bluefin on your plate should you choose? If you had to pick one, the third—the true farmed variety (if you can find a restaurant that serves it)—would, at least, take some of the pressure off the decimated populations of wild fish.

But here’s another idea: When you sit down at the sushi bar, ask your chef what he’d recommend besides bluefin. What most sushi lovers don’t realize is that tuna was never a traditional sushi fish in Japan in the first place—the red, fatty flesh was considered too cloying. It wasn’t until the Japanese began to eat a more Westernized diet in the 20th century, with fattier foods and more red meat, that the cult of bluefin began.

A good sushi chef can introduce you to a flavorful array of more traditional fish that most Americans have never tasted; a few chefs have even made a point of removing bluefin from their menus. If you can’t live without tuna, varieties such as yellowfin and bigeye are less threatened than bluefin. And if you insist on bluefin, save it for the occasional indulgence. Your choices make a difference, and by eating less bluefin, you’ll not only be helping the environment, you’ll actually be getting a more authentic experience at the sushi bar.

Trevor Corson is the author of “The Zen of Fish: The Story of Sushi, from Samurai to Supermarket” (HarperCollins).

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