Asian carp pose a major risk to water ecosystems in North America and wildlife managers have been struggling to keep the invasive species from spreading unmitigated throughout continental waterways.

A new study by the University of Notre Dame, Resources for the Future, and the US Forest Service documents the various barriers available for Asian carp prevention and assesses the effectiveness of each one.

While previous studies have assessed the pros and cons of different Asian carp management strategies, this study, published in the journal Environmental Science and Technology, takes the process further by rating the likelihood of success of the various measures.

"Our study goes beyond just presenting barrier options by putting numbers to how effective various barriers will be, including hydrologic separation and the currently operating electric barrier system," said lead study author Marion Wittmann of the University of Notre Dame.

The researchers estimate that 95-100 percent of Asian carp could be kept from entering the Great Lakes using hydrologic separation methods. However, such a method is more costly than the electric barrier system currently in operation.

While cheaper, the electric barrier option does not keep as many Asian carp from entering the Great Lakes system, the researchers found, noting that the system runs at an 85-95 percent prevention rate.

Other methods on the table include strobe lights, sounds and bubbles to deter the fish. When deployed individually, these methods are between 80 and 100 percent likely to fail, the researchers said. But when they are used in unison between 75 and 95 percent of Asian carp could be kept out of Lake Michigan, the researchers said.

"Protecting the Great Lakes from invasive species eventually comes down to understanding how effective a management strategy may be, how much it will cost and what the benefits of those options are," said study co-author David Lodge, director of the University of Notre Dame's Environmental Change Initiative. "Here we have estimated the efficiencies of various barriers without having to wait for more barrier testing and while the fish are swimming closer to the Great Lakes."

With no natural predators in American waters, Asian carp are a major threat to the biodiversity in water ecosystems. If allowed to establish themselves in the Great Lake system, the Asian carp will consume other fish species, wiping out the food sources of native fish.

"An important finding of this study is that knowledgeable experts identified clear differences in the likely effectiveness of some Asian carp prevention technologies as opposed to others," said co-author John Rothlisberger, an aquatic ecologist with the US Forest Service. "Physical separation stands out from the rest as having the least associated uncertainty and the highest probability of preventing the introduction of Asian carp into Lake Michigan."