Asian grass carp could pose a significant risk to the Great Lakes, according to a new study. In the years between 2007 and 2012, at least 45 of the animals have been caught in the waterways. 

The U.S. government has already invested more than $200 million trying to stop the spread of the invasive species. 

Grass carp are herbivores, eating plants that live at the bottom of the lakes. The effect grass-eating carp have on ecosystems has not been studied in as much detail as plankton-eaters, like silver and bighead carp. Plankton is a vital food source for many species of marine life, making it an essential part of any aquatic food system. 

Many conservationists fear Asian carp could push other species in the Great Lakes to extinction. If this occurs, it could ruin both the natural diversity of the lakes, as well as the region's multibillion dollar fishing industry. 

Although grass does not play as large of a role in the underwater biotic system as plankton, researchers suggest those people interested in preserving the natural state of waterbodies should also pay attention to grass eaters. 

Oddly, grass carp are being purposely introduced into a pond in New Fairfield, Connecticut. These fish are a sterile variety, incapable of reproducing. Officials there hope the animals will help wipe out Eurasian watermilfoil. Town officials say using the fish to control the milfoil infestation will only cost one-tenth as much as using herbicides. 

"Obviously, this will have to be discussed by our Board of Selectmen. But personally, I think it's sort of a no-brainer," Sherman First Selectman Clay Cope said.

Aquatic farmers in the south used to raise the fish for maintenance of waterways. They were first introduced to aquatic farms in the United States in 1963.

Grass carp have already affected much of the Mississippi River Basin and ecologists want to stop the fish before they get to the Great Lakes in greater numbers, though canals and rivers. The species is already found in 45 states, and research shows the fish can survive, and thrive, in all the Great Lakes. 

Details of the study into invasive Asian grass carp populations in the Great Lakes was published in the Canadian Journal of Fisheries and Aquatic Sciences.