Seafood Watch, the program run by the Monterey Bay Aquarium, has updated their “Super Green: Best of the Best” list of seafood that’s good for you and good for the environment. To read an updated blog post on healthy seafood, click here .
Even though I keep up with the news on fish and health, I still get confused when it comes to buying seafood. Between worrying about contaminants like mercury and chemicals such as PCBs that I should avoid, wanting to get enough of the healthy omega-3 fats that are good for my heart and brain, and feeling like I should make an environmentally friendly choice, I have a hard time figuring out which fish is OK to eat given all my concerns. (What’s in your fish? Is it toxic? )
So I’ve stopped guessing at the fish counter. I just stick to these 6 fish and shellfish, identified as the “Best of the Best” when it comes to seafood that’s good for you and good for the environment by Seafood Watch, a program of the Monterey Bay Aquarium. (And I avoid these 6 fish: bluefin tuna, Chilean sea bass (aka Patagonian toothfish), groupers, monkfish, orange roughy and farmed salmon because they carry high levels of mercury and PCBs and their populations are depleted. Find out more here .)
To make this “Super Green” list, fish must: a) have low levels of contaminants—below 216 parts per billion [ppb] mercury and 11 ppb PCBs; b) be high in omega-3s; 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.
1. Salmon (wild-caught, Alaska)
(Find a recipe for Blackened Salmon Sandwich and 20+ more easy, healthy salmon recipes here .)
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 950 mg of omega-3s and carry few contaminants) and more sustainable than just about any other salmon fishery.
2. Pink Shrimp (wild-caught, Oregon) & Spot Prawns (wild-caught, British Columbia)
(Get the recipe for Emeril Lagasse's Shimp Ceviche and dozens more delicious, healthy shrimp recipes here.) 
Most shrimp are plentiful and reproduce quickly. But whether they are sustainably farmed and harvested is the big question. In an effort to reduce the by-catch caused by netting and prevent ocean floors from being scraped clean by dragging, the U.S. has strict regulations on farming and trawling. The best choices are wild-caught MSC-certified pink shrimp (aka cocktail shrimp) from Oregon or their larger sisters, spot prawns, also from the Pacific Northwest, which are caught by traps. Avoid: imported shrimp, farmed or wild.
3. Mussels & Oysters (farmed)
(Get recipes for Steamed Mussels in Tomato Broth and more healthy seafood recipes here.) 
Farmed mussels and oysters are good for you (a 3-oz. serving of mussels contains 700 mg of omega-3s and oysters pack 44 percent of the recommended daily values of iron). Better yet, they are actually good for the environment. Both 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.
4. Sardines, Pacific (wild-caught)
The tiny, inexpensive sardine is making it onto many lists of superfoods and for good reason. It packs more omega-3s (1,950 mg!) per 3-oz. 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.
5. Rainbow Trout (farmed)
Though lake trout are high in contaminants, nearly all the trout you will find in the market is 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.
6. Albacore Tuna (troll-or pole-caught, from the U.S. or British Columbia)
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 U.S. 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. Pregnant women and young children should consider chunk light tuna instead; it’s lower in mercury.