The zebra mussel, a thumbnail-sized mollusk, is a nuisance aquatic species found widely in the United States. Once introduced into lakes, rivers, and saltwaters, it kills off native mollusks and competes with zooplankton for food, in turn, affecting natural food webs. Neither the zebra mussel, nor its close relative the quagga, have been found in Washington waters–yet. The species are widespread in 19 states including the Great Lakes area.

Native to the Caspian and Black Seas, zebra mussels came to the United States in the mid-1980s through ballast water released from foreign ships. Along with the potential to do serious ecological damage, the mussel species has the ability to clog pipes and mechanical systems of industrial plants, utilities, locks, and dams. These mussels are hitchhikers, and easily transported on boats, trailers, and other recreational watercraft.

Incident: This incident highlights the regional and international nature of invasive species and Washington’s heightened concern for zebra and quagga mussels.

On February 3, 2008, a Canadian resident had flown to Nevada and purchased a boat moored in Lake Mead. The man rented a truck to cart his 24-foot watercraft home. He left Lake Mead for British Columbia with a boat and an attached village of mussels in tow. While Nevada regulations require boats to be decontaminated before leaving a marina, budget constraints and personnel shortages have hindered the enforcement of such laws. At 9 p.m. that day, a California Fish and Game inspector stationed at a mandatory checkpoint, stopped the boat owner and his pack of quagga hitchhikers. The boat would have been hosed down there, but problems with the station’s decontamination equipment prevented the inspector from cleaning the boat. Instead, the inspector allowed the Canadian resident to continue his journey after securing his assurances that the boat would be professionally decontaminated once he reached his destination.

California contacted the U.S. Fish and Wildlife Service, and employees there alerted Oregon and Washington. Early February 4, employees of the Washington Department of Fish and Wildlife learned the boat and its owner were headed north on Interstate 5 to the Washington border. After discussions with counterparts in British Columbia and Oregon, Washington Fish and Wildlife staff stepped into action. The Oregon State Patrol escorted the Canadian resident and boat from Oregon to the Port of Entry weigh station in Ridgefield, Washington. The Washington Department of Fish and Wildlife employees inspected and decontaminated the boat at 4 p.m. February 4. As many as 10,000 juvenile quagga mussels were attached to the boat’s trim tabs and lower unit. Most were less than one-eighth of an inch long and appeared alive. Crews hosed down the watercraft with a 140-degree hot water pressure washer and then cleaned with bleach. The owner received a certificate of inspection and decontamination before being allowed to proceed. Department staff informed their British Columbia counterparts that the decontamination was completed. A British Columbia biologist performed a follow-up inspection at the owner’s residence.

The quagga mussel incident demonstrates that an interagency and interstate coordination network is working to prevent the introduction of harmful invasive species. However, communication glitches need to be fixed and nonuniform regulatory and decontamination capacities must be resolved.