Shrimp is America’s favorite seafood. About half of it is farmed—and much, if not most, of that comes from Asia. But as we’ve reported, overseas shrimp farms, with some exceptions, leave a lot to be desired. Though they’ve made shrimp very cheap in recent years (think “all you can eat” shrimp deals) and provide a tasty and excellent source of protein, problems of uncontrolled or illegal use of antibiotics, fungicides, and pesticides are rampant in industrialized shrimp aquaculture. Plus, the farms are infamous for polluting waterways, destroying natural habitats, and having high disease rates, among other problems.
What about the farming of other types of shellfish—notably clams, oysters, and mussels? Are such operations any better? Yes, a lot. In fact, these shellfish are in many ways the ideal seafood to farm because they have little, if any, impact on the environment.
A sustainable option
Farmed clams, oysters, and mussels are typically raised in suspension systems in the open ocean or bays (they hang in the water on ropes or plastic trays, or in mesh bags), with few or no chemicals used. And because farmed shellfish eat plankton naturally found in the water, rather than fishmeal, they don’t deplete wild fish populations.
What’s more, because they are filter feeders, they can actually reduce water pollution. There’s also little or no risk of a clam, oyster, or mussel escaping its pen and interbreeding with its wild counterparts—a common occurrence in other types of aquaculture, notably salmon farming.
About 90 percent or more of the oysters, mussels, and clams consumed worldwide are farmed. Most scallops and other types of shellfish, however, are still wild-caught.
Finding Better Shrimp
If you’re willing to do a little detective work, you can seek out responsibly raised or sustainably sourced shrimp using these tips and resources.
Farmed oysters, clams, and mussels get lots of thumbs-up ratings from seafood-sustainability guides, such as those from Monterey Bay Aquarium and Environmental Defense Fund. Importantly, the ratings generally apply to both domestic and imported sources, since these types of shellfish farms tend to be well managed worldwide. (In contrast, most farmed shrimp make “avoid” lists.) So it’s no surprise that some farmed shellfish also carry certification from such organizations as the Aquaculture Stewardship Council, Global Aquaculture Alliance, and the Denmark-based group Naturland, as well as from the Canadian government (Canada Organic), which ensures that they meet certain criteria for being farmed in ecologically responsible ways.
Moreover, mussels and oysters have respectable levels of heart-healthy omega-3 fats—500 to 1,000 milligrams per 3 ounces, versus less than 200 milligrams in shrimp. Clams have 200 to 500 milligrams. (By comparison, salmon has anywhere from 500 to 1,500 milligrams of omega-3s per serving.)
The safety angle
A potential downside of any shellfish is that, as filter feeders, they can concentrate marine bacteria and viruses (such as Vibrio and hepatitis A), which can cause potentially serious illness if shellfish is eaten raw or partially cooked. Pregnant women and young children should eat only fully cooked shellfish, as should anyone who is immunocompromised, has certain medical conditions (including liver or chronic kidney disease, diabetes, cancer, or stomach disorders), or is otherwise in frail health.
Published January 12, 2016