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Seafood FAQ: Alleviate consumer concerns about farmed shrimp
The environmental community's accusations have prompted consumers to ask more questions about the crustacean's origins
March 01, 2005
Thanks to the emergence of aquaculture in the ’80s and ’90s, shrimp has established itself as America’s favorite seafood. U.S. per capita shrimp consumption jumped from 2.2 pounds in 1990 to 4 pounds in 2003, stealing the No. 1 position from canned tuna in 2001.
But the crustacean’s rise to stardom hasn’t come without pressure from the environmental community, which continues to accuse the shrimp-farming industry of using the potentially lethal antibiotic chloramphenicol, destroying mangroves, harming the environment and displacing traditional livelihoods in rural Asian and Latin American communities. As a result, some consumers are questioning whether they should eat shrimp. Here are the answers to a few common concerns.
Q. Is chloramphenicol still used in shrimp farming?
Most countries, including the United States, have banned the use of chloramphenicol in animal-food production. The Food and Drug Administration has a zero-tolerance policy for the antibiotic in food sold in the marketplace. The agency, which currently has a detection level of 0.3 parts per billion, has tested seafood for chloramphenicol since 2002 and has detained product containing the antibiotic.
“I’ve talked to people at FDA who say a lot of shrimp-farming countries have initiated educational campaigns to discourage the use of [banned] antibiotics at the farm level,” says Thor Lassen, president of Ocean Trust in Reston, Va., who released a report called “Shrimp Sustainability Review” last August.
Research over the past 25 years has consistently found that any amount of chloramphenicol is potentially lethal to humans, according to the Public Citizen report “Chemical Cocktail: The Health Impacts of Eating Farm-Raised Shrimp,” which was released last December. The report is the second of six the Washington, D.C.,
consumer-advocacy group is due to release by April as part of the anti-farmed-shrimp campaign it launched last April.
Little research exists on the toxicity of chloramphenicol, says the Global Aquaculture Alliance in St. Louis. But the group points to a recent Dutch study that found an individual must consume an inordinate amount of shrimp containing traces of chloramphenicol to be at risk of developing cancer.
According to the study, if a 154-pound individual consumed 0.3 ounces of shrimp per week containing 10 ppb of chloramphenicol, he or she would be exposed to 0.17 parts per trillion of chloramphenicol per day. That’s 5,000 times less than the dose estimated to increase the risk of cancer in one out of 1 million individuals.
Q. What does farming shrimp have to do with mangroves?
Mangroves are intertidal shrubs found in tropical and subtropical climates. They serve as a source of food in coastal ecosystems and as a breeding ground for many species of fish and shellfish. The removal of mangroves can harm coastal ecosystems, as well as accelerate coastal erosion.
Some members of the environmental community say construction of shrimp ponds is responsible for mangrove destruction. Up to 38 percent of global mangrove loss is tied to shrimp farming, according to the 2003 Environmental Justice Foundation report “Smash and Grab: Conflict, Corruption and Human Rights Abuses in the Shrimp-Farming Industry.”
But according to the GAA, less than 5 percent of global mangrove loss is attributed to shrimp farming. The practice of removing mangroves to build shrimp ponds has mostly stopped, says the group. Agriculture, urban development and the use of wood for building material and fuel are mainly to blame for mangrove destruction.
Most mangrove destruction occurred 20 to 30 years ago, before the boom in shrimp farming, adds Lassen. Moreover, the soil in mangrove wetlands is highly acidic, which is unfavorable to shrimp farming, he says. Farmers prefer to build shrimp ponds in upland areas where the soil is less acidic.
Q. How do shrimp farms affect the environment?
Shrimp are raised in brackish ponds. Usually, water is pumped into the ponds from nearby estuaries and discharged back into the estuaries or settlement ponds. If the water-exchange rate is too high, excess nutrients can be discharged back into the estuaries, leading to algae blooms that suffocate sealife.
The water-exchange rate can reach 40 percent daily, according to the Public Citizen report “Shell Game: The Environmental and Social Impacts of Shrimp Aquaculture,” which was released last November.
But according to Lassen, most farmers limit the water-exchange rate to 2 to 5 percent daily, down from 10 to 30 percent daily in previous decades. In the last 10 years, the amount of water discharged per kilogram of shrimp produced has been cut in half, he adds. That’s because more farmers are reducing water-exchange rates and switching from open to closed systems during the growout stage to protect shrimp from disease.
Additionally, more farmers are adding settlement ponds to catch excess nutrients, says Lassen. In Thailand, which represents about one-quarter of total U.S. shrimp imports — more than any other country, 10 to 15 percent of ponds larger than 15 acres must be devoted to a settlement pond.
Q. What are the social effects of shrimp farming?
Some members of the environmental community contend that the expansion of shrimp farming displaces traditional livelihoods such as rice farming, reducing the availability and diversity of agricultural products. In Thailand, nearly half of the land used to raise shrimp was once used to grow rice, according to the EJF report “Smash and Grab.”
Lassen argues that the expansion of shrimp farming generates employment in rural areas with few other job opportunities. Most Asian shrimp farmers are small-scale farmers owning less than 12 acres of land.
Between 1.2 million and 1.5 million full-time jobs are created by shrimp farming, and an additional 3.6 million to 9 million jobs are created indirectly at the hatchery, processing, distribution and exporting levels, says Lassen. The Food and Agriculture Organization values the global shrimp crop at nearly $7 billion at the farm level.