An unwelcome visitor in the form of an invasive giant prawn has scientists saying they are worried for the future of the Gulf of Mexico's ecosystem.

The Asian tiger prawn, which can grow to a foot long, with a voracious appetite and an unfortunate tendency to carry disease, has invaded the northern gulf and could be a threat native species from crabs and oysters to smaller brown and white shrimp, researchers said.

"It has the potential to be real ugly," Leslie Hartman, Matagorda Bay ecosystem leader for the Texas Parks and Wildlife Department, told the Houston Chronicle. "But we just do not know."

Native to the western Pacific, tiger prawns have been showing up along the Gulf Coast since 2006, but this year saw a huge increase in their numbers, researchers said.

Their presence raises concerns about large-scale aquaculture in the gulf, since tiger prawns carry at least 16 viruses, such as white spot, which can be lethal to other shrimp.

"We need to be really, really cautious," George Leonard, who leads the Ocean Conservancy's aquaculture program, said.

Tiger prawns eat the same types of food as native shrimp species but will also prey on their smaller cousins, as well as on crabs and young oysters, researchers said.

"It's a large, competitive species," Tony Reisenger of the Texas Sea Grant program at Texas A&M University said.