The Montana Invasive Species Council commissioned the study by the University of Montana Flathead Biological Station.
The Flathead Beacon reports that the study only examined a percentage of the total economic impact that invasive mussels could have on the state.
Council chair Bryce Christiaens says mussels can cover boat launches and beaches and cause damage to the state’s ecosystems and infrastructure.
State wildlife officials have been trying to prevent invasive mussel species from being introduced to the state since 2005. Larvae were found at Tiber and Canyon Ferry reservoirs in 2016. So far, no adult mussels have been found in Montana.