Environment

Biologists in Kentucky are working on an experimental barrier that they hope will deter invasive Asian carp from entering the state’s two largest lakes.

Asian carp reproduce quickly and have dispersed across the South and Midwest since they were first introduced to the U.S. in the 1970s.

The fish crowd out native species for space and eat zooplankton, small organisms that make up the base of the freshwater food chain — leading to worries about widespread disruption of native habitats.

Jessica Morris, a fisheries biologist with Kentucky Department of Fish and Wildlife, heads up a crew trying to slow the spread of Asian carp.

“And so if these fish feed on those [plankton] their whole life cycle, then that reduces the amount of plankton in our waterways for our native fish,” Morris said.

Asian carp are already present in Kentucky’s two largest lakes — Lake Barkley and Kentucky Lake — and so far eradication efforts have been focused on encouraging commercial fishing to thin out the Asian carp population.

Now state and federal officials have partnered on an experimental technology they hope will deter the fish from entering bodies of water — a device that uses light, bubbles and sound to specifically target Asian carp.

“The speakers will be mounted on the bottom of the river bed facing up to get the sound up into the water column. They’re not just broadcasting the sound widely, it’s confined in that wall of bubbles,” Morris said.

The first installment of the Biological Acoustic Fish Fence, or BAFF, will be built on the river bottom just below the Lake Barkley Dam, where a massive number of Asian carp hang out.

To demonstrate just how many Asian carp are camping below Barkley Dam, biologists at KDFW recently invited media to observe while they electrified the water to stun the fish.

Video of the event posted on the Facebook page “War On Carp” shows hundreds of fish leaping from the water as biologists collect them in a boat to tag them with tracking devices.

Morris says that the BAFF should help keep as many of the fish from entering the lock at Lake Barkley when river barges come through.

“Through the lock chamber is the only way that Asian carp can get into Lake Barkley through this dam structure. So if we can cut them off at moving through the lock then that’ll reduce the number of Asian carp going into Lake Barkley,” Morris said.

Biologists will be monitoring to see if as many of the Asian carp make it through Barkley Dam into the lake using transponders that have been surgically installed in many of the fish.

If the BAFF proves effective, Morris says officials will try to build another one in neighboring Kentucky Lake, which is connected to Lake Barkley with a canal.

“And so once we have deterrents placed there, then we anticipate our commercial harvest continuing in the lakes, reducing the numbers of Asian carp that are present in those systems,” Morris said.

The fish fence is scheduled to be finished this fall with hopes to build another fence in the coming years.

Ryland Barton is the Capitol bureau chief for Kentucky Public Radio.