Tuna, packed in questions

If you eat canned tuna for lunch, you're among millions of Americans who polish off almost a billion pounds of tuna a year, more than 95 percent of it canned. Partly because the size of cans has been reduced, we're eating less canned tuna, though sales of fresh tuna are up. We juggle price, flavor, value, and health benefits while worrying about the dangers of mercury, unwanted additives, environmental degradation, carbon footprint, and the loss of America's tuna fishery and cannery jobs.

Yikes, that's a lot to think about when buying a can of tuna!

To make sense of it all, I compared 19 cans of tuna, all labeled dolphin-safe, ranging in price from 13 cents per ounce for Duet chunk light, double-cooked, unidentified species from Thailand to 88 cents per ounce for American hand-filleted, hand-packed, sashimi-grade single-cooked albacore loins from American Tuna.

What to Look For

1. No additives. But price per ounce doesn't tell the whole story. Most inexpensive canned tuna contains two ingredients that turn the fish into sponges so it absorbs more water that drains right out: soy (often listed as vegetable broth containing soy) and sodium pyrophosphate. You may be paying less money, but what you're getting is less tuna and more additives. Three companies, StarKist, Bumble Bee, and Chicken of the Sea, represent more than 80 percent of America's canned tuna, but most of their products contain additives, something easily checked in the can's list of ingredients.

2. Cooked only once. To get that tuna in the can, large operations freeze the fish on board, fillet it on shore, cook the fillets, freeze again, defrost, and finally cook it once again in the can. It's no wonder much of the flavor and heart-healthy omega-3 oils are lost. America's artisanal canneries cook their tuna once in the can, maintaining flavor, meaty texture, juiciness, and omega-3 oils.

3. Low mercury. With tuna at the top of the food chain, mercury is a concern. The Food and Drug Administration recommends that we eat up to 12 ounces (2 average meals) weekly of fish and shellfish low in mercury, including canned light tuna, but only 6 ounces of the higher-in-mercury albacore. However, a study by Oregon State University's Seafood Laboratory showed that "troll-, bait-, and line-caught albacore off the West Coast of the U.S. had lower levels (of mercury) as their size is smaller than albacore caught in tropical waters by long-lines."

Larger, older albacore from deeper waters will be higher in mercury, as will mature yellowfin.

A 2006 independent study sponsored by the national nonprofit Defenders of Wildlife recommended consumers "avoid brands of light canned tuna that comes from Latin American countries, especially Ecuador and Mexico, because of their astonishingly high average level of mercury." The study found that Asian brands of tuna, especially from Thailand, had the lowest mercury levels on average; it also found American brands to be a better choice than Latin American brands.

Because a quarter of the tuna we eat is at food-service establishments, where price rules, we are probably consuming more mercury than we realize.

4. High omega-3 oils. Because line-caught albacore swim in the cold waters of the North Pacific feeding on anchovies and sardines, they contain 10 times as much omega-3 oils as other tuna - 2.6 grams per 2-ounce (56-gram) portion. Mild albacore tuna, with pinkish white flesh, is rich in omega-3s, as is Spanish Bonito del Norte.

5. Line-caught, American. Our tuna-canning industry grew out of the Pacific sardine fishery in Monterey, Calif. When the sardine catch declined precipitously in the early 20th century, an enterprising sardine canner began packing his empty cans with albacore tuna, which proved to be a perfect food for American soldiers abroad. By 1954, America had become the world's largest producer and consumer of canned tuna.

Today, only about one third of albacore comes from America, caught and packed by companies like Papa George, Tuna Guys, Pacific Fleet, Crown Prince, Wild Planet, Oregon's Choice Gourmet Albacore, and American Tuna. They are revitalizing a local, sustainable fishery where fishermen use only pole and lines, instead of vast nets, catching fish one by one, with no "by-catch."

Natalie Webster is co-owner of American Tuna, formed by six traditional fishing families, many of Portuguese origin and in their fifth generation of fishing on the West Coast.

When their boats carrying 10 to 20 tons of tuna come to shore (and that's considered small-scale), each fish is ticketed with the date, weight, and captain's and vessel's name, and can be traced through processing to the can. They export 95 percent of that catch, mostly to Spain, for high-end canned tuna; Webster would like to see more of that fish stay here. (And the word is spreading: Their tuna is being used for sandwiches at the upscale Blue Hill at Stone Barns in New York, among others.)

For Webster, one big concern is "IUU (illegal, unregulated, unreported) fish, sold at less than market value." She is proud of her company's laurels: "We are the only domestic tuna canner to have earned Marine Stewardship Council certification. Labels don't mean much unless someone," such as the council, "is checking."

6. Species of tuna. Seafood Watch, a program of Monterey Bay Aquarium, recommends British Columbia or West Coast American or Hawaiian pole and troll albacore as a best choice - the only canned tuna to get its green light.

Skipjack is our most common canned light tuna. Fished in tropical waters, it is generally found to have lower levels of mercury. Tongol, or longtail tuna, canned as "light" or "tongol," comes mostly from Thailand and Indonesia. Its off-white meat is tender and mild and it is generally low in mercury.

Fishing for huge bluefin dates back thousands of years in the Mediterranean. Canned bluefin is highly prized in Tunisia (named after tuna) and in Italy, but is usually canned only when smaller bluefin mix with other species in the catch. Yet bluefin is to be avoided, as it is on Seafood Watch's red list as "severely overfished in all oceans."

Bonito is closely related to tuna but cannot be labeled tuna in many countries. Firm, flavorful Spanish Bonito del Norte, a favorite of chefs and aficionados, is actually albacore, high in omega-3 oils.

Yellowfin, labeled "light" or "yellowfin," has pale pink flesh, and is much appreciated for its full-bodied flavor and meaty texture. But it is also often criticized for its high mercury level, especially in larger and older fish. Solid-pack "tonno" (Italian for tuna) in olive oil is usually large yellowfin.

7. Labels don't tell all. Most cans don't include the country of origin, or omega-3 and mercury content. (You can check the Web site www.defenders.org for the study "Is Your Tuna Family-Safe?" for some of this information.)

About one-quarter of our canned tuna is "white," which is always albacore. The remainder is "light," often skipjack, but it may also be yellowfin, tongol, bonito, bigeye, or even bluefin. Chunk tuna consists of small bits and is less expensive. Higher-priced, solid-pack tuna consists of whole loin sections so there's more tuna in the can.

In the end, in spite of all the studies and research that are already available, consumers still need more information in order to make good choices about the tuna we consume.