6 of the Healthiest Fish to Eat (And 6 to Avoid)

You probably already know that you're supposed to be eating fish twice a week. Fish are a lean, healthy source of protein -- and the oily kinds, such as salmon, tuna, sardines, etc., deliver those heart- and brain-healthy omega-3 fats you've probably also heard you should be getting in your diet. But then there's also this concern about sustainability -- and choosing seafood that's sustainable. Knowing what seafood is best for your health and the environment is not always easy.

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Fortunately, Seafood Watch, the program run by the Monterey Bay Aquarium, has combined data from leading health organizations and environmental groups to come up with its list "Super Green: Best of the Best" of seafood that's good for you and good for the environment.

To make the list, last updated in January 2010, fish must: a) have low levels of contaminants -- below 216 parts per billion [ppb] mercury and 11 ppb PCBs; b) be high in health-promoting omega-3 fats; and c) come from a sustainable fishery.

Many other options are on the program's list of "Best Choices" (seafoodwatch.org). The Blue Ocean Institute (blueocean.org) also has sustainability ratings and detailed information.

Here are 6 fish -- that are healthy for you and the planet -- that Seafood Watch says you should be eating.

Lemon Caper Tuna and Noodles

Many tuna are high in mercury, but albacore tuna -- the kind of white tuna that's commonly canned -- gets a Super Green rating as long as (and this is the clincher) it is "troll- or pole-caught" in the United States or British Columbia. The reason: smaller (usually less than 20 pounds), younger fish are typically caught this way (as opposed to the larger fish caught on longlines). These fish have much lower mercury and contaminant ratings, and those caught in colder northern waters often have higher omega-3 counts. The challenge: You need to do your homework to know how your fish was caught, or look for the Marine Stewardship Council (MSC) blue eco label.

Herbed Salmon

To give you an idea of how well managed Alaska's salmon fishery is, consider this: Biologists are posted at river mouths to count how many wild fish return to spawn. If the numbers begin to dwindle, the fishery is closed before it reaches its limits, as was done recently with some Chinook fisheries. This close monitoring, along with strict quotas and careful management of water quality, means Alaska's wild-caught salmon are both healthier (they pack 1,210 milligrams of omega-3s per 3-ounce serving and carry few contaminants) and more sustainable than just about any other salmon fishery.

Farmed oysters are good for you (a 3-ounce serving contains more than 300 milligrams of omega-3s and about a third of the recommended daily values of iron). Better yet, they are actually good for the environment. Oysters feed off the natural nutrients and algae in the water, which improves water quality. They can also act as natural reefs, attracting and providing food for other fish. One health caveat: Raw shellfish, especially those from warm waters, may contain bacteria that can cause illnesses.

The tiny, inexpensive sardine is making it onto many lists of superfoods, and for good reason. It packs more omega-3s (1,950 milligrams!) per 3-ounce serving than salmon, tuna, or just about any other food; it's also one of the very, very few foods that's naturally high in vitamin D. Many fish in the herring family are commonly called sardines. Quick to reproduce, Pacific sardines have rebounded from both overfishing and a natural collapse in the 1940s.

Lemon and Herb Grilled Trout Sandwiches

Though lake trout are high in contaminants, nearly all the trout you will find in the market is farmed rainbow trout. In the U.S., rainbow trout are farmed primarily in freshwater ponds and "raceways" where they are more protected from contaminants and fed a fishmeal diet that has been fine-tuned to conserve resources.

Freshwater coho salmon is the first -- and only -- farmed salmon to get a Super Green rating. All other farmed salmon still falls on Monterey Bay Aquarium's Seafood Watch "avoid" list for a few reasons. Many farms use crowded pens where salmon are easily infected with parasites, may be treated with antibiotics, and can spread disease to wild fish (one reason Alaska has banned salmon farms). Also, it can take as much as 3 pounds of wild fish to raise 1 pound of salmon. Coho salmon, however, are raised in closed freshwater pens and require less feed, so the environmental impacts are reduced. They're also a healthy source of omega-3s -- one 3-ounce serving delivers 1,025 milligrams.

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