Talk about majesty of the seas. The bluefin is surely the king of tuna - an awesome powerhouse of muscle, speed, and endurance.
Yet it has been so overfished that some predict it may never recover. The oil spill in the Gulf of Mexico - the only known spawning ground for the population in the Western Atlantic - has heightened concerns.
Many people are aware of the cautionary advice: Don't eat the bluefin. Most of us can't anyway. Conservation-minded businesses aren't carrying it, and those that do charge sky-high prices.
But there are plenty of other tuna fish in the sea, and they deserve our attention as well.
Otherwise, says Carl Safina, president of the Blue Ocean Institute, a conservation organization, "we'll lose them, also."
Bluefin used to be so numerous that people sold them for a nickel a pound for cat food, he says.
"So what people take for granted today is something that gets overexploited and demolished tomorrow. It's certainly a cautionary tale that everybody should know."
Year after year, tuna is one of the most-consumed fish in the United States. Canned tuna alone - the burgeoning market for tuna steaks and sushi notwithstanding - is regularly second only to shrimp.
Seafood counters and even grocery aisles of canned tuna offer a baffling array.
At the Reading Terminal Market last week, I came across albacore, yellowfin (also known as ahi), and a few others labeled simply "tuna."
At a Whole Foods, the canned offerings went from Bumble Bee's "chunk light" at $1.39 for six ounces through skipjack and tongol to American Tuna's "pole-caught wild albacore" for $4.99.
Which of these tunas is a good choice for the eco-minded? The answer is complex.
One thing is for sure: With a simple tuna dinner - whether tuna salad, grilled tuna steak, or sushi - there's a whole pile of fishing politics on the plate as well.
Because tuna are highly migratory, their populations are managed by a patchwork of nations and international organizations, with varying results. Scientists recommend quotas, but then a political process for determining the catch takes over, and typically overrides the recommendations.
The United Nations Food and Agriculture Organization reports that most stocks - regional populations - of the major market tuna species are "about fully exploited."
The International Seafood Sustainability Foundation - a partnership of scientists, industry, and the conservation organization WWF - comes at it from a different direction: the kinds of tuna we actually eat.
Between 80 to 85 percent of the tuna we eat comes from healthy stocks, says foundation spokesman Mike Crispino.
Tipping the balance is skipjack, a staple of "chunk light" canned tuna, which amounts to 57 percent of all tuna eaten worldwide. Skipjack is in good shape.
Still, Crispino cautions, "by no means is it a case of, oh, the coast is clear."
Where and how a tuna is fished are hugely important. And mind-bogglingly complicated.
The biggest problem today, Crispino says, is bycatch - the unintentional catch of other species when you're fishing for just one.
For instance, skipjack are so numerous that they are sometimes called rabbits of the sea. Because they mature at an earlier age than other tuna species, they can withstand heavier fishing.
Yet most skipjack are caught in purse seines - large nets that are dragged into a circle around a school of fish, then cinched closed. Young tuna of other species are often caught, along with sharks and sea turtles, and many die.
In the Gulf of Mexico, yellowfin tuna are caught by longline - a line stretched up to 40 miles, with other lines and hooks dangling beneath.
Advocates say longlines help fishermen target species more accurately by, say, changing the size of the hook.
But they do catch sea turtles and bluefins, says Lee Crockett, director of federal fisheries policy for the Pew Environment Group.
To help sort this out, numerous organizations publish seafood and sushi consumer guides that include tuna. Many factor in stock assessments, fishing methods, bycatch concerns, and even health alerts for contaminants like mercury, a concern in some larger fish.
California's Monterey Bay Aquarium has a pocket-size guide that can be downloaded and printed off the Web, as well as an iPhone app.
As a broad generalization, U.S.-caught fish are preferable because regulations are stricter and enforced better. Still, some U.S. stocks are considered overfished, as is the case with North Atlantic populations of albacore.
Fish caught by pole-and-line - a commercialized version of trolling from a sport boat - are generally considered better because there's less bycatch.
But not all tuna are labeled, and store clerks may not know.
Overall, however, environmentalists credit chains that are moving toward sustainability and transparency - notably Wal-Mart and Target - with nudging the market in a better direction. When I asked a clerk at Whole Foods last week how some of the fish were caught, he consulted a lengthy computer printout.
Interest in sustainability is also spawning a growing boutique fishery for tuna.
Just as consumers are now seeking out bird-friendly coffee, they're trying delicacies like the can of $4.99 American Tuna offered at Whole Foods. Or the tongol - a tuna with growing popularity - from a store brand, 365 Everyday Value.
Many companies promote their meat as "wild caught," which has meaning for other fish species but not tuna, which are all but exclusively caught in the wild.
And, akin to the early days of organic labeling, they say that their product is "sustainably fished" - a term that is not legally defined.
There is a certification organization. The Marine Stewardship Council uses independent third-party evaluators to review fisheries - units defined by stock, geography, and fishing methods. If the council's logo is on a can or display tag, it means that the fish came from a certified operation.
The first tuna fishery to be certified, in 2007, was the American Albacore Fishing Association, a family company that runs a fleet of boats out of San Diego. With the new cachet, the white-tablecloth and European markets opened up to the once-struggling company, and it could hardly meet demand.
"Businesses around the world are convinced sustainability is not a passing interest, but it's becoming central to the way we live and do business," says Kerry Coughlin, the stewardship council's regional director for the Americas. "You can debate how steep a curve it is, but no one will debate it's going up."
Farming tuna is difficult, in part because the fish are highly migratory. Recently, however, the industry has succeeded in growing bluefin larvae in a lab - test tube tuna - and raising them to adulthood in captivity.
Farmed bluefin is still expensive - up to $12 for a single piece of sushi at one restaurant - and the taste is not quite the same. But kindai has been enthusiastically received, says Joe Lasprogata, director of purchasing for Samuels and Son Seafood Co. Inc., a Philadelphia wholesaler that no longer sells wild bluefin.
Raising fish on farms doesn't equal sustainability. Critics note that a bluefin needs to eat massive amounts of other fish. In the wild, it would feed randomly as it travels. On a farm, its food fish are often harvested en masse.
Not everyone is comfortable with reducing complex issues to a sort of good-fish, bad-fish mind-set.
In a way, says Paul Greenberg, the author of Four Fish: The Future of the Last Wild Food, a new book about the demise of wild tuna, salmon, bass, and cod, it salves the public and robs the activist community of oomph.
"It is a good idea, from a moral standpoint, to choose the right fish," he says. But it can't stop there.
Find out who the suppliers are, he suggests, "and then start writing letters."
GreenSpace: Finding a Better Tuna: Online Guides
Several organizations offer consumer guides to seafood.
Monterey Bay Aquarium (www.montereybayaquarium.org): Online guide for regions of the country, printable pocket guide, and iPhone app. Ratings for each species include "best choices," "good alternatives," and "avoid." Includes information about mercury. Also has a separate guide for sushi.
Blue Ocean Institute (www.blueocean.org): Online and wallet guides. Has five levels of recommendations. "Green" species are relatively abundant, with fishing methods that cause little damage to habitat and other wildlife. "Red" species face a combination of problems such as overfishing, high bycatch, and poor management. Includes information about mercury. Also has a sushi guide.
FishWatch (www.nmfs.noaa.gov/fishwatch): National Oceanic and Atmospheric Administration program skips recommendations, but has a wealth of information about U.S. fisheries, including population levels, nutrition information, habitat, and bycatch.
- Sandy Bauers