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Eating seafood can be healthy for you and the environment—if you choose mindfully.
Eating from the ocean is complicated. On one hand, we face health cautions associated with seafood. Toxins like methylmercury from coal-fired plants and polychlorinated biphenyls (PCBs) from a variety of industrial processes have entered the marine food web. Methylmercury levels in some seafood and large fish like swordfish, many species of shark, and bigeye, yellowfin, and bluefin tuna all regularly exceed the Environmental Protection Agency’s mercury safe limit of o.3 parts per million by more than 2o percent. Both mercury and PCBs have been shown to cause damage to the nervous system and can impair heart health when consumed at high levels.
Along with this troubling news, we hear that the ocean has been “overfished”—meaning that we’re catching more fish than can be replaced through natural reproduction. Even those who choose farmed seafood instead of wild in an effort to preserve the ocean’s supply may find themselves in an environmental quandary. For example, to grow a single 10-pound farmed salmon, a farmer must feed that fish more than 15 pounds of wild fish because farmed fish aren’t available as feed. Fish farming, in other words, could result in a net loss of wild fish.
But the story about fish is not entirely dire. Seafood is rich in heart-saving, brain-building omega-3 fatty acids. When compared to other meats like beef, seafood can have a lower carbon footprint. And not all seafood is in peril. As you wade through the options within the seafood category, you can choose mindfully to minimize the impact on the environment. Here are seven seafood selections that are good both for you and the planet.
1. Alaskan Sockeye Salmon
Remember, it takes 1.5 pounds of wild salmon to grow one pound of farmed salmon. In general, then, wild Alaskan salmon is a better choice than farmed salmon if you’re looking to preserve wild fish populations. But not just any wild salmon: More than one-third of those harvested in Alaskan waters start their lives in a hatchery. This practice, begun in the 197os, was meant to artificially boost harvests. But some biologists worry that hatchery fish lack the genetic characteristics that wild fish have gained over time to adapt to their waters. Thus, pumping so many hatchery fish into rivers and streams where they’re free to spawn may threaten the long-term survival of wild populations.
Your Best Choice: Wild Alaskan sockeye salmon, which is the least supplemented by hatcheries. As a bonus, sockeye has some of the highest levels of omega-3s and lowest levels of mercury and PCBs among salmon. Although sockeye has been overfished in the past, excellent management—ensuring that an adequate number of spawners are left in the water for the next year and enlisting fish counters statewide for monitoring—is now in place, as demonstrated by more than a decade of consistently high returns to Alaskan rivers. Biologists are forecasting the 2o15 run in Bristol Bay (the nation’s biggest wild sockeye fishery) to be the largest in 15 years. In all, 52 million sockeye are anticipated, up from a low of less than 2o million in 2oo2.
2. Farm-Raised Catfish
If every person in the world were to eat the two portions of seafood a week that most physicians recommend, the wild ocean would need to produce three times its current yield. The trick, then, is to find species of farmed fish that don’t require wild fish to grow. US farm-raised catfish are fed primarily corn and soy, a diet similar to cattle feed. But because catfish (and indeed nearly all fish) are cold-blooded and don’t have to spend as much energy resisting gravity as land creatures, they can much more efficiently process feed. In other words, far less feed is required to grow an American catfish than to grow an American cow. And because cattle emit methane—a major greenhouse gas—as part of their digestive process, fish end up having a much smaller carbon footprint than cows, making fish a good choice of protein.
3. Farmed Clams, Mussels, and Oysters
Clams, mussels, and oysters don’t require any fish as their feed. In fact, they grow plump and sweet by making the water a healthier place for fish to live. Here’s how the system works: For years, excess nitrogen from fertilizers and wastewater-treatment plants has made its way into the marine environment. The nitrogen acts as a fertilizer and causes algae to bloom in the ocean. When bacteria eat dead alga e, they consume oxygen, which can create oxygen-poor dead zones where fish can’t survive.
This is where clams, mussels, and oysters come in. They eat the algae and remove it from the water before it can damage coastal ecosystems. And because the algae have high levels of heart-healthy omega-3 fatty acids, the filter feeders that eat the algae can also contain very high levels of the recommended nutrients. Mussels, for example, have omega-3s at levels equivalent to canned tuna—without the mercury concerns of certain tuna types. Also, because filter feeders eat at the bottom of the food web, organic pollutants, which accumulate the higher you go up the food chain, are rarely a concern.
It’s best to choose farmed clams, mussels, and oysters so as not to subtract wild filter-feeders from the aquatic system. Most farming of clams, mussels, and oysters is done in ocean waters, so it helps clean the environment while allowing the wild supply to be sustainable.
4. Sablefish or Black Cod
Since the passage of the 1996 Sustainable Fisheries Act, overfishing has been actively opposed and more than three dozen American fish species have been restored to sustainable levels. A major rebuilding success story has been US sablefish, also known as “black cod.” Although sablefish have moderate levels of mercury (from o.o9 to o.29 parts per million), according to the Natural Resources Defense Council, levels are generally lower than for similarly large fish. Plus, they are rich in omega-3s and are managed under strict quota systems.
5. Sea Bass
Among other fish-rebuilding success stories have been two fish, both called “sea bass:” black sea bass on the East Coast and white sea bass on the West. “Sea bass” is more of a marketing name than a taxonomic designation, and West Coast white and East Coast black sea bass are biologically very different. Like sablefish, sea bass were seriously overfished in the 197os and 198os, and then populations were rebuilt in the 2ooos. Both of these fish are near-shore dwellers, so they are often caught by small day-boat American fishermen and marketed directly to consumers through a new kind of seafood distribution system called a community-supported fishery, or CSF. Like community-supported agriculture systems, CSFs cut out the many middlemen between producer and consumer. In a CSF system, fishermen sell shares in their catch ahead of time, allowing them to gear up at the beginning of a season.
Supporting local fishermen has clear environmental and economic benefits, as well: Currently, about 90 percent of the seafood Americans eat is imported, traveling an average of nearly 5,5oo miles to reach our plates, according to a recent study published in Fisheries Research. But CSF-caught fish, on the other hand, journey less than 5o miles from boat to plate.
6. Pacific Spot Prawn or Oregon’s Pink Shrimp
Shrimp are the most popular seafood in America. We eat about 4 pounds of shrimp per person per year—almost as much as the combined intake of the next two top seafoods (salmon and tuna). Nearly 9o percent of the shrimp we eat is imported, which has caused problems across the globe because hundreds of thousands of acres of mangrove forest in Southeast Asia and Latin America have been leveled to make way for shrimp farms. Wild imported shrimp are problematic too, as they’re usually trawled in fine-meshed nets that can result in more pounds of accidentally killed “bycatch” than of the targeted shrimp. (Rates in shrimp fisheries have ranged from 2 to 1o pounds of bycatch for every pound of shrimp landed.) Bycatch routinely gets dumped overboard as waste. Trawling foreign shrimp and then shipping them to American markets also burns quite a bit of fossil fuel: worst case, shrimp-trawl fisheries use 4,ooo liters of fuel for every metric ton landed.
The best option, then, is American and Canadian Pacific spot prawns. These 5- to 8-inch-long crustaceans are caught in traps, which minimizes bycatch. Also, they are harvested after they’ve spawned and just before they will die of natural causes. Spot prawns are expensive—about double the price of your standard commodity shrimp— so a cheaper alternative is Oregon’s pink shrimp, which are smaller and sweeter, caught by midwater trawling with minimal bycatch, and available canned from companies like Wild Planet and fresh, particularly on the West Coast.
7. Sardines and Herring
Sardines on the West Coast and Atlantic herring on the East Coast are a much easier catch, and thus less burdensome on the environment. Because sardine and herring nets are pulled through open water with no bottom friction, these “small pelagics” require less than a tenth of the fuel to catch than bottom-trawled seafoods like flounder and sole. Sardines and herring are also rich in omega-3s and low in environmental toxins. But there is one hitch: Most American sardines and herring are used as lobster and tuna bait or salmon feed, while the sardines and herring available for human consumption generally come from other countries. But if we ask our local fishmongers to supply American-caught sardines and herring, the market will likely respond to our demands.