You Are What You Eat: The Ocean on Your Plate

©istockphoto/LauriPatterson

Fish is good for us. And roughly 25 percent of all protein we consume comes from the sea. Keeping our oceans full of fish isn’t just good for SCUBA divers, wildlife lovers and National Geographic specials: it’s a major factor in how we’ll feed a growing world.

But there’s something fishy about buying fish. When you show up at the fish counter, you’ll find a baffling array. Line caught? Trawl-caught? Farmed? Wild? Different methods are used to obtain each type of fish, with varying effects. As the saying goes, there’s no such thing as a free lunch. Here’s what you should know about how it ends up on your plate.

Avoid Toxins: Eat Low on the Food Chain
To protect yourself from toxins like mercury, eat fish that are relatively low on the food chain, and that don’t live for a really long time. Fish like bluefin tuna, which are predators that live for more than 30 years, gradually accumulate toxins from their prey, which then get passed on to you when you eat them. Smaller fish with shorter life spans (like Pacific salmon, which live only 3-5 years) accumulate fewer toxins.

Good Fisheries and Bad
Where a fish is caught matters—even if the fish is the same. That’s because some fisheries are well managed to provide a stable yield without fishing out the entire population. If you’re after a Chinook (King) salmon, get it from the well-managed Alaska fishery before you buy it from Washington, where salmon runs are in danger. Want a rockfish? Get one caught in California, where a fishery collaborative has protected their breeding areas.

Say Bye-Bye to Bycatch
Fishing techniques vary with the species, the sea, and the industry. Gillnets scoop up everything in a section of the sea—including lots of fish that they don’t want, called “bycatch.” Bycatch is often tossed, dead or injured, back into the sea. Gillnets can also trap air-breathers like dolphins or sea turtles. Purse seines are a bit more selective, catching entire groups of schooling fish in a small area. The best options are line-catching, trolling and jigging, which are more selective and allow fishermen to quickly remove bycatch before they die.

Keep the Bottom In Shape
Bottom-trawls and dredges scrape the seafloor in search of bottom fish like flounder, cod and halibut. This damages the seafloor, which can be slow to recover, as the collapsed New England cod fishery can attest to. Avoid fish caught through bottom trawls when you can. Traps that sit on the bottom and that fish swim or crawl into (imagine a giant lobster or crab trap) are a better option.

Smart Farming
In the future, more of our fish will come from farms, called Aquaculture. This seems sensible because we can chow down without depleting the sea. But how it’s done matters. Net-pen salmon farms have been an ecological disaster in Scotland, Chile, and are also threatening British Columbia. They raise Atlantic Salmon that often escape and spread disease to wild fish, and the chemicals used to keep them free of sea lice harm the ocean food chain. But put in tanks on land, where the water is carefully treated, fish farms can work well. Farmed salmon are a no-no, but Tilapia and Giant Tiger Prawns raised in onshore farms are a great option.

Vote With Your Dollar
The sign at the fish counter may not say if the cod they’re selling was jigged in Alaska or bottom-trawled off Newfoundland. Ask. More grocery stores and restaurants have realized that consumers want to know. Seafood Watch, a smartphone app from the Monterey Bay Aquarium, can help you make good choices.