Carp scare affects Minnesota

Asian carp species are moving up the Mississippi River, endangering native plants and animals.

Allison Wickler

The silver species of Asian carp can jump up to 10 feet out of lakes and rivers, hitting boaters and causing injury and potentially death, according to the U.S. Fish and Wildlife Service.

Although this might seem extreme, the problems these fish can cause are much more significant on a broader ecological level and they may be coming to Minnesota.

Asian carp are a group of four species – bighead, black, grass and silver – of invasive, non-native fish that were originally brought to the United States from China in the 1960s and 1970s to aid in the biological control of algae in Arkansas.

The fish escaped from aquaculture facilities and began spreading to southern states and up the Mississippi River. They now account for up to 90 percent of the fish biomass in areas of the river near Illinois and Iowa, said Ray Norrgard, a wetland and wildlife specialist at the Minnesota Department of Natural Resources.

Their presence reduces the abundance of native aquatic plants that provide food and breeding environments for native species and can also reduce the presence of aquatic animal species.

Some Asian carp can grow to five feet in length, weigh up to 110 lbs. and eat 40 percent of their body weight per day, according to U.S. Fish and Wildlife Service data. Research has shown they are moving up the Mississippi River at 40 to 50 miles per year.

So far in Minnesota, one bighead carp was found in the St. Croix River in 1996 and one was caught in Lake Pepin in 2003, according to the Minnesota Department of Natural Resources.

University professor Peter Sorensen of the department of fisheries, wildlife and conservation biology works with the problem of the invasive common carp, which he said are different than Asian carp and are already abundant in Minnesota.

He said nobody in Minnesota is working specifically on the Asian carp threat because Asian carp aren’t abundant here yet and because it competes with other issues which also need money.

“But there’s absolutely nothing to stop them from moving further north and everyone’s just waiting for it to happen,” he said.

Norrgard said most people don’t realize the harm that common carp can cause, much less the dire threat Asian carp pose.

The four species together eat vegetation, plankton, invertebrates and mollusks, Norrgard said.

“If you put them all together in the Mississippi River, then you’ve affected every single aspect of that food chain,” he said.

Phyllis Windle, senior staff scientist in the Union of Concerned Scientists’ Global Environment Program, said she hopes solutions like putting large, electric barriers across rivers to stop the fish from moving upstream can combat the problem. But she said that seems to be the only short-term solution for now.

Young silver Asian carp are often used as bait and are transported much farther than they could have originally traveled, Windle said.

Kevin Denny, president of the University’s Hunting and Fishing Club, said the group tries to promote good ethics by not transporting species away from where they were obtained.

“If someone is bringing their own bait, we try to make sure it’s from the source where we are fishing,” he said.

Since the 1990s, people concerned about Asian carp have pushed for their inclusion on the list of invasive species in the Lacey Act, Windle said. That’s currently the only way the United States regulates imports and interstate transport of invasive species.

There are versions of invasive species legislation in both the House of Representatives and the Senate, she said, but the measures most likely will not pass this year.

Despite the challenges, Sorensen said she’s optimistic scientists can effectively combat the Asian carp problem.

“If you get some smart people together and some money and give them some time, I think we can do things,” he said. “I really think science is very powerful.”