A big increase in reports of Asian tiger shrimp along the U.S. Southeast coast and in the Gulf of Mexico has federal biologists worried the species is encroaching on native species' territory.
The shrimp are known to eat their smaller cousins, and sightings of the massive crustaceans have gone up tenfold in the last year, biologists say.
The black-and-white-striped shrimp can grow 13 inches long and weigh a quarter-pound, compared to eight inches and a bit over an ounce for domestic white, brown and pink shrimp.
Scientists fear the tigers will bring disease and competition for native shrimp. Both, however, can be eaten by humans.
"They're supposed to be very good,' Pam Fuller, a biologist with the U.S. Geological Survey told CNN. "But they can get very large, sorta like lobsters.'
The last U.S. tiger shrimp farm closed in Florida in 2004, without ever raising a successful crop, according to a USGS fact sheet about the species.
Reports of tiger shrimp in U.S. waters rose from a few dozen a year - 21 in 2008, 47 in 2009 and 32 in 2010 - to 331 last year, from North Carolina to Texas.
'That's a big jump,' Ms Fuller told the Associated Press.