Mississippi River / Bighead carp In Lake Pepin Raises Alarms

October 9, 2007

Release from: Dennis Lien
Pioneer Press

Another bighead carp has been caught in Lake Pepin, raising new concerns about the northern migration of the voracious invader.

The 29-pound fish was netted Wednesday, south of Frontenac, Minn., by three commercial fishermen, according to Jay Rendall, invasive species prevention coordinator for the Minnesota Department of Natural Resources. Rendall said they knew immediately what they had caught and notified the DNR fisheries office in Lake City, which confirmed the find.

Bighead carp are one of several types of Asian carp that were imported to the United States more than three decades ago, escaped into the wild and now threaten to overwhelm native fish populations in the Mississippi River watershed. They have taken over large portions of the Illinois and Missouri rivers and are becoming increasingly common in the Mississippi as far north as central Iowa.

It was the second bighead caught in Lake Pepin, a widening of the Mississippi between Minnesota and Wisconsin. Four years ago, three commercial fishermen netted a 23-pound bighead on the southern end of the lake, about 10 miles southeast of the most recent catch.

Tim Adams of Wabasha, Minn., was in both boats.

This time, he and his partner, George Richtman of Trempealeau, Wis., and a crew member were using a large net for buffalo and common carp, and were bringing in their catch when one of the fish caught their attention.

"You could tell him apart,'' Adams said. "Just the color of him. We knew we had something we weren't supposed to have."

"He had no doubt,'' said Kevin Stauffer, area fisheries supervisor out of Lake City. "He called us right away."

The fish was 39.4 inches long and weighed 28.7 pounds. Bigheads can exceed 50 pounds.

Authorities said they aren't sure how the two bighead carp got this far north, but do not believe they are part of a reproducing population.

"Until we see more of them, or some evidence of reproduction, I don't see anything that has really changed," Rendall said. "But it is another reminder that our window of opportunity is getting shorter for trying to prevent a population from becoming established here."

As part of an effort to slow the northern migration, the state is backing an experimental underwater sound-and-bubble barrier that could be built just north of Dubuque, Iowa. Congress recently authorized $4 million for the project, but that money hasn't been released yet.

The proposed barrier would be north of where bigheads are believed to have advanced and much farther north of where silver carp, which can leap out of the water and strike boaters, have gotten so far.

The bighead and silver carp are large filter-feeders that were brought to the U.S. to help clean up water in southern fish farms.

Many of those fish escaped or were released, and have been gradually expanding their range.

In many parts of the Illinois and Missouri rivers, they dominate the aquatic ecosystem. They consume the plankton that are the foundation of the aquatic food chain and compete directly with larval fishes, paddlefish, buffalo and freshwater clams.

They also are hard to catch with hook-and-line equipment or to net, making it difficult to assess their range.

Dennis Lien can be reached at dlien@pioneerpress.com or 651-228-5588.