The zebra mussel has been a poster child for invasive species ever since it unleashed economic and ecological havoc on the Great Lakes in the late 1980s. Yet despite intensive efforts to control it and its relative, the quagga mussel, these fingernail-sized mollusks are spreading through U.S. rivers, lakes and bays, clogging water supply pipes and altering food webs.
Now, the mussels threaten to reach the country’s last major uninfested freshwater zones to the west and north: the Columbia River Basin in Washington and Oregon, and the waterways of Alaska.
