Economic costs of mussels infestation in Montana

Abstract

Publication: Flathead Lake Biological Station, University of Montana

A 2019 study by research economist Nanette M. Nelson of the Flathead Lake Biological Station assessed the potential economic impact of dreissenid mussels—an invasive species including zebra and quagga mussels—if they were to colonize all of Montana’s water bodies. These mussels pose a serious threat to ecosystems and infrastructure by clogging water intakes, degrading water quality, and altering aquatic environments. Using water usage data and cost models from infested regions, the study estimated statewide economic damages ranging from $96 million to $234 million annually in mitigation and lost revenue.

Additionally, Montana could face $288 million to $497 million in private property value losses, primarily around high-value lakefront properties. The most heavily affected sectors would include tourism, irrigation, and hydroelectric power generation. The Columbia River Basin, still free of invasive mussels, is especially at risk due to its economic reliance on recreation and hydropower. The report emphasizes the importance of prevention and early detection, noting that Montana’s current invasive species funding—about $6.5 million—is only a fraction of the cost that could result from inaction. The study offers a scalable, data-driven model that policymakers can use to justify proactive investment in mussel prevention programs.