Environment & Science
4:01 pm
Sat August 4, 2012

A new Asian Carp threat in Michigan waters

State wildlife officials are concerned that a potentially damaging fish has turned up in the St. Joseph River in Berrien County.

It wasn’t that unusual when a fisherman pulled a 33 pound Grass Carp out of the St. Joe River a month ago.   But the fact that the carp was capable of reproducing was unusual.

Most Grass Carp caught in Michigan waters are genetically altered so they can’t reproduce.   They come from private ponds, often in Indiana where they are legal to have with a permit.   Grass Carp are banned in Michigan.    

The fish are used to reduce aquatic plant life. They’re very good at doing that.   Too good,  according to Jay Wesley of the Department of Natural Resources.

“They eat about 30 percent of their body weight per day. So they could eat a lot of vegetation,” says Wesley.

Wesley says that could eventually affect native fish species.    He also notes that the St. Joe River flows into Lake Michigan, potentially spreading Grass Carp. 

It’s unclear where this particular fish came from or if there are other Grass Carp capable of reproducing in Michigan waters.