Shrimp - Why Some Shrimp Should Be Avoided
Wild shrimp are usually caught by trawling. That's a fishing method in which large nets are towed through the water or dragged along the seafloor. Trawl nets scoop up everything in their path: shrimp, fish, sea stars, even endangered sea turtles. Fishermen keep the valuable shrimp, but often discard the other, unwanted animals (known as "bycatch").
Shrimp trawl fisheries have among the world's highest highest levels of bycatch. According to the U.S. National Marine Fisheries Service, in the Gulf of Mexico, three pounds of bycatch are caught for every pound of shrimp that goes to market. According to the Worldwide Fund for Nature, in the Gulf of Thailand it can be 14 pounds of bycatch per pound of shrimp. The bycatch, crushed in the net and then dumped on deck, is usually discarded dead or dying. Sea turtles, already critically endangered, have been killed by the thousands in shrimp trawl nets.
Concerns about bycatch have led fishermen to develop devices they can put on their nets to reduce unwanted catch. The "bycatch reduction device" (BRD) and the Nordmore grate are net modifications that help fish escape from shrimp nets. All U.S. shrimp trawlers—and all foreign fleets selling shrimp in the U.S—are supposed to outfit their nets with trap-door "turtle excluder devices," or TEDs, to let sea turtles escape. However, not every nation enforces TED use.
A better alternative is wild shrimp caught in traps. This fishing method produces little bycatch; any unwanted animals that end up in the traps can be released alive. We consider trap-caught shrimp a "Best Choice."
What about farmed shrimp?
Most of the world's shrimp is farmed in Southeast Asia, where valuable coastal wetlands, especially mangrove forests, are often destroyed to create commercial shrimp farms. This reduces habitat needed by juvenile fishes, which means fewer fish for local people to catch for their protein needs and fewer fish in the food web sustaining marine life. Mangrove forests help shelter the coastline from tropical storms, and when the forests are gone, storm damage to coastal settlements is more severe.
Where shrimp are cultivated intensively, pollutants and disease organisms build up in the muck beneath each pond. After a few years, the pond can no longer support healthy shrimp. The pond is abandoned and the farm must expand to fresh territory. The contaminated muck cannot support regrowth of the mangrove forest, so the ecosystem will not recover for decades, if ever. While some countries now have laws to protect their mangrove resource, shrimp are so valuable on the international market that the pressure to develop shrimp farms is still strong.
Some shrimp farms are environmentally friendly. They are located inland, away from sensitive coastal habitat. Water is recirculated, and wastewater is treated to remove pollutants.
However, because there is currently no way for consumers to tell the source of most farmed shrimp on the market, we maintain a general recommendation to avoid farm-raised shrimp from unknown sources.
Information courtesy of Monterey Bay Aquarium. Visit their site. www.montereybayaquarium.org