ABSTRACT

ABSTRACT Quagga mussels (Dreissena rostriformis bugensis) and zebra mussels (Dreissena polymorpha) are dreissenid species native to eastern Europe and western Russia. First discovered in the Great Lakes in the late 1980s, they are now considered invasive species throughout North America. Dreissenid mussels use byssal threads to attach and hitchhike between unconnected waterbodies. Resource managers began to recognize the signi‘cance of the eastern North American invasion in the early 1990s. It is widely accepted that trailered boats introduced the mussels to western United States waters, where they were ‘rst reported in the Lake Mead National Recreation Area in January 2007. The invasive mussels are now found in all western states except Idaho, Oregon, Washington, Montana, Wyoming, Alaska, and Hawaii. The mussels would have asigni‘cant economic impact if they are introducedto Idaho’s waters and infrastructure systems. In response to this threat, the Idaho Legislature enacted progressive Invasive Species Laws in 2008 to establish state agency authorities and prevent the mussels from being introduced to the state. Through these policies, the state operates highway-based stations to inspect boats that are entering the state. More than 100 mussel-fouled boats have been interceptedby Idaho’s program to date. The chances of eradicating anew population of zebra or quagga mussels in an Idaho waterbody will depend directly on the ability of the state to respond quickly. Idaho has developed an exclusion strategy and contingency plan in the event prevention fails.