Seafood Done Smart

By Andrew Rice

My wife and I fight about fish.

Other couples may fight over the remote control, about whose in-laws will get a holiday visit, or about who left the toilet seat up (again). We don't, but sometimes we do fight about the relative merits of mariculture (fish farming) vs. wild-caught fish. My wife recoils at the thought of eating farm-raised Atlantic salmon as if it were pen-raised veal. I'm troubled by the overfishing of wild stocks of fish all over the world. At other times, we squabble about whether we should let our son eat yellowfin tuna, which we all love, but which also contains high levels of mercury.

Our various struggles are just a microcosm of the larger debates about eating fish. The fact is, there's no one easy answer when it comes to picking fish that is healthy, environmentally sustainable, affordable, and delicious. But don't worry; with a little research, it's possible to find the right fish to grace your dinner table. Here are some tips.

Fish fat: fabulous for you!

There wouldn't be much point in eating fish if it were bad for us. To begin with, seafood is a great source of protein, generally low in fat and reasonably low in cholesterol. But it has other benefits too. The National Oceanic and Atmospheric Administration (NOAA), which runs America's national marine sanctuaries, says research has shown that eating seafood may reduce our risk for a number of unhealthy conditions, including stroke, hypertension, and heart disease.

Why is it seafood that has these benefits rather than, say, a giant cheeseburger? Because seafood is rich in certain polyunsaturated fatty acids commonly known as omega-3 fatty acids whereas the cheeseburger is just rich in fat. Not all fish are made equally when it comes to their omega-3 content. The best are cold-water fish, like wild salmon, albacore tuna, mackerel, and herring. Studies by the Washington State Department of Fisheries have found that wild and farmed salmon both have roughly the same amounts of omega-3s per portion. Sardines and other small fish are also excellent sources.

Malevolent mercury

Of course, the flip side of the health equation is the concern about levels of methylmercury in fish. This heavy trace metal is the fallout of industrial pollution of the atmosphere, largely from the burning of coal, and has been linked to brain damage and birth defects. All fish contain some mercury, but the health benefits of most fish species generally outweigh the downside. The best rule of thumb is to avoid large fish that live a long time, as they accumulate the most mercury in their flesh. The EPA advises that consumers avoid shark, swordfish, and king mackerel. Smaller fish like sardines, anchovies, and herring tend to have the lowest mercury levels, as do shellfish like shrimp, lobster, and scallops. Larger fish like halibut, tuna, and salmon have higher levels but not dangerously so, unless you eat them in very large quantities.

o keep your mercury levels in the safe zone, the Natural Resources Defense Council advises eating unlimited quantities of low-mercury species like tilapia, anchovies, catfish, and freshwater trout. You should limit your intake of moderate-mercury species like halibut, lobster, and mahi-mahi to less than six servings per month. Eat no more than three servings per month of high-mercury species like tuna, albacore, and sea bass. And, as mentioned earlier, entirely avoid species like shark, swordfish, and king mackerel.

Is seafood safe for kids?

The verdict on whether or not to feed my 9-year-old son the yellowfin tuna sushi he loves so much (aka maguro, at your local sushi joint) turned out to be a hung jury. According to the Natural Resources Defense Council Web page about mercury levels in fish, both children under 6 years of age and pregnant women should avoid high-mercury species entirely. According to the NRDC, at 9, my son can safely eat tuna, albacore, and other varieties in the high-mercury category, but he should limit his intake to less than 1 ounce of tuna per 12 pounds of body weight per week (in his case, about 6 ounces per week), which is a pretty good portion of sushi.

If you think you or your loved ones might already be suffering from elevated mercury levels, the Sierra Club offers mercury testing for $20.00 per person. You simply download and print out the brochure here, fill it out, and mail it in to the address provided with a sample of hair cut according to the instructions. They'll test it and mail the results back to you in about a month.

The impact on our oceans

Finally, there are a lot of valid concerns about the environmental impact of our fish-eating habits, whether it's the depletion of wild tuna stocks by industrial fishing fleets or the localized pollution caused by pens of farm-raised salmon. Even more complicated, a fish that's okay to eat from one ocean or area, like California halibut, might be overfished or endangered in another, like Atlantic halibut.

The best single resource I've found for navigating the environmental questions around any species of fish or shellfish is the Monterey Bay Aquarium's Seafood Watch Web site and downloadable buyer's guide. A PDF of the guide, customized for various regions, is available at http://www.montereybayaquarium.org/cr/cr_seafoodwatch/download.aspx.

I also downloaded the Seafood Watch app from the iTunes^® store, which is great for checking whether or not you should buy that delicious-looking monkfish fillet on sale at your favorite grocery store. (The answer? No, because it's caught by trawlers that also catch endangered sea turtles.)

A short list of common species that are both mercury safe and environmentally sustainable includes domestically farmed freshwater fish like tilapia, catfish, and trout; wild-caught Alaskan salmon; Pacific halibut; sardines; and mahi-mahi.

Maybe now my wife and I can start fighting about something really important, like who's going to clean up after our seafood dinner.