Shrimp's Dirty Secrets: Why America's Favorite Seafood Is a Health and Environmental Nightmare

Americans love their shrimp. It's the most popular seafood in the country, but unfortunately much of the shrimp we eat are a cocktail of chemicals, harvested at the expense of one of the world's productive ecosystems. Worse, guidelines for finding some kind of "sustainable shrimp" are so far nonexistent.

In his book, Bottomfeeder: How to Eat Ethically in a World of Vanishing Seafood, Taras Grescoe paints a repulsive picture of how shrimp are farmed in one region of India. The shrimp pond preparation begins with urea, superphosphate, and diesel, then progresses to the use of piscicides (fish-killing chemicals like chlorine and rotenone), pesticides and antibiotics (including some that are banned in the U.S.), and ends by treating the shrimp with sodium tripolyphosphate (a suspected neurotoxicant), Borax, and occasionally caustic soda.

Upon arrival in the U.S., few if any, are inspected by the FDA, and when researchers have examined imported ready-to-eat shrimp, they found 162 separate species of bacteria with resistance to 10 different antibiotics. And yet, as of 2008, Americans are eating 4.1 pounds of shrimp apiece each year -- significantly more than the 2.8 pounds per year we each ate of the second most popular seafood, canned tuna. But what are we actually eating without knowing it? And is it worth the price -- both to our health and the environment?

Understanding the shrimp that supplies our nation's voracious appetite is quite complex. Overall, the shrimp industry represents a dismantling of the marine ecosystem, piece by piece. Farming methods range from those described above to some that are more benign. Problems with irresponsible methods of farming don't end at the "yuck," factor as shrimp farming is credited with destroying 38 percent of the world's mangroves, some of the most diverse and productive ecosystems on earth. Mangroves sequester vast amounts of carbon and serve as valuable buffers against hurricanes and tsunamis. Some compare shrimp farming methods that demolish mangroves to slash-and-burn agriculture. A shrimp farmer will clear a section of mangroves and close it off to ensure that the shrimp cannot escape. Then the farmer relies on the tides to refresh the water, carrying shrimp excrement and disease out to sea. In this scenario, the entire mangrove ecosystem is destroyed and turned into a small dead zone for short-term gain. Even after the shrimp farm leaves, the mangroves do not come back.

A more responsible farming system involves closed, inland ponds that use their wastewater for agricultural irrigation instead of allowing it to pollute oceans or other waterways. According to the Monterey Bay Aquarium's Seafood Watch program, when a farm has good disease management protocols, it does not need to use so many antibiotics or other chemicals.

One more consideration, even in these cleaner systems, is the wild fish used to feed farmed shrimp. An estimated average of 1.4 pounds of wild fish are used to produce every pound of farmed shrimp. Sometimes the wild fish used is bycatch -- fish that would be dumped into the ocean to rot if they weren't fed to shrimp -- but other times farmed shrimp dine on species like anchovies, herring, sardines and menhaden. These fish are important foods for seabirds, big commercial fish and whales, so removing them from the ecosystem to feed farmed shrimp is problematic.

Additionally, some shrimp are wild-caught, and while they aren't raised in a chemical cocktail, the vast majority is caught using trawling, a highly destructive fishing method. Football field-sized nets are dragged along the ocean floor, scooping up and killing several pounds of marine life for every pound of shrimp they catch and demolishing the ocean floor ecosystem as they go. Where they don't clear-cut coral reefs or other rich ocean floor habitats, they drag their nets through the mud, leaving plumes of sediment so large they are visible from outer space.