Aquatic Invasive Species
Date Published: October 2010
Number of Pages: 76
Author(s): Allen Pleus, Eric Anderson, Jesse Schultz, and Larry LeClair, WDFW and Bill Balcom, Washington State Patrol
“The Dreissena [zebra and quagga mussels] is perhaps better fitted for dissemination by man and subsequent establishment than any other freshwater shell; the tenacity of life, unusually rapid propagation, the faculty of becoming attached by string byssus to extraneous substances and the power of adapting itself to strange and altogether artificial surroundings have combined to make it one of the most successful molluscan colonists in the world.” (Kew, H.W. 1893)
The Washington Department of Fish and Wildlife (department) and the Washington State Patrol (WSP) continue to implement the legislative invasive species directives established since 1998. This report is submitted to the legislature for meeting the requirements of both Chapter 43.43.400(4) and 77.12.879(4) RCW and describes the challenges found and actions taken to implement the program. The program is primarily funded through dedicated fees on resident recreational watercraft as provided through ESSB 5699 (2005 c 464). The legislation established the Aquatic Invasive Species (AIS) Prevention and Enforcement Programs, which are managed by co-AIS coordinators in the department Fish and Enforcement divisions and in collaboration with the WSP enforcement liaison in the Commercial Vehicles Division. Although the AIS Prevention and Enforcement programs address many priority aquatic invasive species, the greatest focus has been on Zebra (Dreissena polymorpha) and Quagga (Dreissena bugensis) mussels.
The environmental, economic, and social/human health risks of zebra and quagga mussels can be catastrophic. Zebra and Quagga mussels are ecosystem changers that are continuing to completely alter the aquatic communities in the Great Lakes and other watersheds where they have become established. Health risks include contamination of water supplies, increased occurrences of blue-green and other toxic algae blooms, ability to concentrate contaminated sediments up to 300,000 times ambient levels and then disperse these into the food chain through direct consumption or through fecal matter, which has then killed wildlife and could sicken humans. They are also a freshwater bio-fouler that can quickly reduce or stop flows in hydro and water supply systems, plug water cooling systems in watercraft motors, and create physical hazards to fish and humans as their shells are capable of cutting skin.
A recently released report by the Independent Economic Advisory Board at the request of the Northwest Power and Conservation Council found that it is likely zebra and quagga mussels will eventually colonize some of the large rivers of the Columbia Basin, and that there is much value in delaying this result for as long as possible. Furthermore, there is a substantial economic risk in the hundreds of millions of dollars annually if these mussels become established in the Columbia Basin and that costs to mitigate for zebra or quagga mussels at hydropower facilities within this basin would be significantly greater than those incurred at other infested sites around the country due to their comprehensive fish passage facilities. They concluded that it would be a good economic investment to improve prevention programs to delay an infestation.
It is important to note that the Columbia River basin and the Pacific Northwest in general, are among the last large river or regional drainage basins in the continental United States that remain free of zebra or quagga mussels. This is due to a combination of increasing prevention measures and luck. Within this area, the highest risk for introductions of zebra and quagga mussels and other aquatic invasive species is by hitchhiking on recreational and commercial watercraft that are being transported from other infested parts of the United States and Canada. There is also a growing threat of interstate transportation through ballast water if freshwater ports in California become infested and are transported to Columbia River ports.
Unfortunately, while the threat of zebra and quagga mussels and other aquatic invasive species increases, the resources to fight this threat have decreased over the past two years due to budget cuts and reductions in other revenue sources used to supplement this work. In addition, it has been recognized that limited regulatory authorities would not be sufficient to contain or eradicate a zebra or quagga mussel infestation if it happened today. Recommendations are provided for establishing the resources needed to address this critical threat.
The following is a brief summary of some AIS Prevention and Enforcement accomplishments that have occurred since the department’s last report to the 2008 legislature.
Early detection actions: High-risk water bodies were annually surveyed statewide for juvenile and adult zebra and quagga mussels. During 2008-2009 alone, a total of 662 plankton tows (looking for free-floating juvenile stage of mussels) were conducted and 177 artificial substrates (looking for adult settling) were deployed at 234 sites throughout Washington. The sites were distributed over 108 different water bodies. To date, no zebra or quagga mussels have been detected. Projections for the number of water bodies that can be surveyed during the 2011-13 season will depend mostly on volunteer efforts as funding reductions will direct most actions to rapid response and watercraft inspections.
Rapid response actions: Twenty-two recreational watercraft have been intercepted in the state since 2006 with zebra, quagga, or other Dreissena mussels attached – all were decontaminated. Ten of these watercraft were carrying live mussels, eight were carrying mussels where it was not possible to determine if they were alive or dead, and four were carrying just the attached shells. An important lesson learned was that shells alone could trigger a rapid response watercraft decontamination or could trigger a large scale rapid response action if they were to drop off at a boat launch. Unfortunately, the ability to fully remove all shells from an infested watercraft is still problematic.
Watercraft inspection actions: Over 12,500 watercraft have been inspected since 2007 through boater surveys, integrated AIS/boater safety inspections, WSP Port of Entry weigh station inspections, and at mandatory AIS check stations. Of these, 22 were found to have zebra or quagga mussels (see above) and 200 watercraft were found to be infested with aquatic plants. Mandatory AIS check stations are staff-intensive, but provide very high direct and indirect value in watercraft owner appreciation for our state’s efforts to prevent AIS introductions. Projections for the number of watercraft that can be inspected during the 2011-13 season is likely to be reduced due to budget cuts. As a comparison, Idaho has a budget of $1.3 million and was able to inspect 44,000 boats in 2010.
Nonresident watercraft analysis: Approximately 10% of all inspected watercraft were registered distributed over 24 other states and two provinces of Canada. Overall, Idaho contributed by far the largest proportion of nonresident registered watercraft (378), followed by Oregon (233), California (74), Arizona (36), British Columbia (22), Utah (13), and Montana (12). Of these, California, Arizona, and Utah have known established populations of zebra or quagga mussels. When nonresident watercraft owners were asked what water body they last used, the result was 85 different water bodies distributed over 13 states and two Canadian provinces. The ten most frequently visited were Coeur d’ Alene Lake, ID (42); Willamette River, OR (18); Dworshak Reservoir, ID (18); Lake Mead, AZ/NV (16); Clear Lake, CA (15); Pend Oreille Lake, ID (12); California Delta, CA (11); Shasta Lake, CA (9); Lake Havasu, AZ/CA (9), and Clearwater River, ID (9). Of those ten water bodies, lakes Mead and Havasu are known to be contaminated with zebra and/or quagga mussels. The remaining 75 water bodies are distributed over eight states and two provinces of which seven of the states are known to harbor infestations of zebra and/or quagga mussels.
State and regional coordination: The department closely coordinates with the Washington Invasive Species Council, the Aquatic Nuisance Species Committee, the Columbia River Basin Team, and the Aquatic Nuisance Species Western Regional Panel to address state and regional issues. For example, a hypothetical detection of zebra mussels at the Two River’s Marina at the mouth of the Spokane River was this year’s annual table-top exercise for the Columbia River Basin Team’s Interagency Invasive Species Rapid Response Plan. Participants on site included department planning and enforcement staff, the U.S. Fish and Wildlife Service, the Pacific States Marine Fisheries Commission, the U.S. Bureau of Reclamation, the Lake Roosevelt National Park Service, the U.S. Army Corps of Engineers, the Spokane Tribe of Indians, the Confederated Tribes of the Colville Reservation, the Upper Columbia United Tribes, the Columbia River Inter-Tribal Commission, the Washington Invasive Species Council, and representatives from the states of Idaho, Oregon, and Montana. The Washington Departments of Ecology and Agriculture provided real-time responses to chemical permit and use questions.
Pleus, A., E. Anderson, J. Schultz, L. LeClair, and B. Balcom. 2010. Washington State Aquatic Invasive Species Prevention and Enforcement Program: Report to the Legislature. Washington Department of Fish and Wildlife and Washington State Patrol. Olympia. October 2010.
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