Invasive Mussels in Montana

In early November 2016, Montana Department of Fish, Wildlife & Parks (MFWP) reported that Tiber Reservoir, east of Shelby, Montana tested positive for zebra mussels. They also reported that Canyon Ferry near Helena had suspect results. Since that time, additional samples from the Milk River downstream of Nelson Reservoir and the Missouri River upstream of Townsend also returned suspect results. This is concerning because Montana had been one of a few remaining western states void of invasive mussels.

On November 30th, 2016 Governor Bullock issued an executive order declaring a statewide natural resource emergency that included the deployment of an interagency rapid response team to tackle the emerging issue. On December 1st, 2016 the state took further action by issuing emergency orders restricting the launch and removal of boats from Tiber Reservoir and Canyon Ferry. Glacier National Park and the Blackfeet Indian Reservation placed moratorium closures to boating, and the U.S. Fish & Wildlife Service closed Jessup Mill Pond outside of Creston in response to the zebra mussel threat. 2017 ushered in a new paradigm for the public’s interaction with Montana waters.

Fortunately, after five years of extensive testing and surveying both reservoirs, no further evidence of invasive mussels has been found. Both reservoirs were declared mussel free in 2022, but we must all take an active role in this issue by spreading the word, talking to our elected officials, and supporting local and statewide AIS prevention efforts.