In many parts of Latin America and Asia, large swaths of coastal mangrove forests have been cut down and turned into shrimp farms. Not only does this deforestation destroy habitat for birds and cause other ecological problems, but it also releases a large amount of the carbon stored in mangrove soil—so much, in fact, that the shrimp end up having a sizable carbon footprint, according to calculations presented here today at the annual meeting of the American Association for the Advancement of Science (which publishes ScienceNOW).

 

To get a handle on how much carbon dioxide is represented by shrimp, ecologist Boone Kauffman of Oregon State University in Corvallis made some estimates based on typical shrimp farms in southeast Asia. He looked at farms that are relatively large and not particularly productive, with harvests yielding 50 to 500 kilograms of shrimp per hectare. These farms, which make up about half of those in the world, only last for 5 years or so before the buildup of sludge in the ponds and the acid sulfate soil renders them unfit for shrimp. “It's the equivalent of slash-and-burn agriculture,” Kauffman said. (Other types of shrimp farms are more efficient and not located in mangrove forests.)