The Minnesota River is infested with invasive zebra mussels and carp, according to the state Department of Natural Resources.
That designation places additional restrictions on commercial fishers, bait collectors and those with permits to pump water from the river.
Young zebra mussels were found in several locations this summer, and a couple of invasive carp have been captured in the river, said DNR invasive carp coordinator Nick Frohnauer.
"It doesn't mean that they're well established or in the case of carp that they're established at all," Frohnauer said. "But it's just a proactive step that the DNR is taking to prevent one of the risk pathways for these species."
Carp have been captured on the river, but there's no evidence they are reproducing, Frohnauer said.