Asian carp, an invasive species that has populated parts of the Mississippi and Missouri rivers in the south, now threatens Minnesota’s northern lakes, according to the Star Tribune. These fish pose a threat to the Minnesota aquatic ecosystems as they outcompete other species for food.

Instead of installing an electric barrier, which has been used in other rivers, the DNR wants to keep the invasive fish from spreading to northern lakes with a barrier of noise and bubbles at the Ford Dam near Fort Snelling.

Although this type of barrier probably won’t be as effective as an electric barrier, it will continue to be safe for boaters who use the lock. The bubbles would serve as a wall for the fish and underwater speakers would produce a sound that Asian carp (who are known to be “noise-sensitive”) cannot tolerate, in hopes of stopping about 60 to 90 percent of the fish from reaching northern waters until another solution is found.

The barrier, which is estimated to cost between $12-$19 million to build (plus $250,000 each year to operate), would span across a channel that funnels boats into the lock. The best and least expensive way to keep the fish from spreading north would be to close the upper lock and dam at St. Anthony Falls in Minneapolis, but it would have to be approved by Congress.