Asian tiger shrimp invade U.S waters

Though tasty with lemon and garlic butter, Asian tiger shrimps are spreading through the Gulf of Mexico and Eastern seaboard and menacing the areas' ecosystems.

The crustaceans can measure up to 13 inches long and weigh nearly a pound, with dark and white stripes circling their bodies. They can be very disruptive to the Gulf's ecosystem, says James Morris, a marine ecologist with the National Oceanic and Atmospheric Administration's Center for Coastal Fisheries and Habitat Research in Beaufort, N.C.

Originally from the western Pacific Ocean, the shrimp have been spotted sporadically in U.S waters for the past two decades. But last year, 331 were counted in the Gulf of Mexico, up from 32 in 2010 and just six in 2006, according to a tally kept by the U.S. Geological Survey (USGS).

Scientists are trying to figure out where the invasive shrimp came from. Theories include that they spawned from a batch that escaped a lab two decades ago or that they immigrated here in the ballast water of ocean-crossing ships.  

DNA testing is expected to show whether they are breeding in the Gulf or were swept in from other regions.