U of M researcher: Physical barriers won't stop Asian carp

Collecting water samples
National Park Service biologist Byron Karns, left, thought the slack water in the auxiliary lock at the Ford Dam might be a likely spot for traces of Asian carp. He was joined by Christina Wille and Stan Zobel.
MPR Photo/Tim Nelson

Physical barriers will not be effective enough to stop invasive species from damaging Minnesota waters, according to a University of Minnesota researcher.

The Coon Rapids Dam had previously been thought to be an effective barrier against Asian carp, but the Department of Natural Resources announced Thursday that it had found e-DNA evidence of the silver carp in the Mississippi River above the dam.

Peter Sorensen has studied carp for years, and helped design an acoustic-bubble carp barrier at his lab at the U of M.

The fish have probably been upstream of the dam for 10 years, Sorensen said.

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"I think we've just lost the first battle," he said. "The silver carp are here, it doesn't mean we've lost the war."

Sorensen said the DNR could install barriers if researchers can figure out where they'd do some good. But he says much more research is needed to craft a holistic approach, that could include engineered diseases that attack certain species.

"We need to develop new technologies, tools, and understandings if we're going to win this war on invasive species, and it's not just silver carp, it's other species too," he said.

Snakeheads may be the next species to arrive, Sorensen said. Australia, which has been dealing with highly destructive invasive species for years, takes a long-term, holistic approach, which often involves biological controls, such as genetically-engineered diseases that target only certain species.