Andrew Burnett, a biologist with the state Division of Fish and Wildlife, told the Star-Ledger of Newark that he saw a nutria swimming across Lower Alloway Creek, a tributary of the Delaware River in South Jersey, in late October.

   The nutria, which can grow as big as 2 feet long and weigh up to 20 pounds, can cause damage in ecosystems where it lacks natural predators. But an exterminator told The New York Post that its size can also make it comparatively easy to eliminate.

   "As long as we don't allow the population to grow, we can eradicate them no matter how big they are," said Leonard Douglen of the New Jersey Pest Management Association.

   The nutria has been spreading northward on the U.S. East Coast and reached Maryland and Delaware about 20 years ago.