SIOUX FALLS, S.D. (KELO) — The Minnesota Department of Natural Resources has confirmed the presence of an invasive species, but it’s not zebra mussels or carp.

Wildlife officials say signal crayfish were found in Lake Winona, which is near Alexandria, Minnesota. This is the first time they have been found in Minnesota waters.

A commercial harvester found several of them in the lake. However, so far there is no evidence of eggs or younger crayfish. They are larger and more aggressive than Minnesota crayfish and can out compete native species for food and habitat.

Signal crayfish can spread between waterways or be transported by people. They can also crawl over land at night and during wet weather.