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Wyoming Game and Fish increases efforts to block mussel infestation

by Wyoming Livestock Roundup

    Although microscopic when young, two species of freshwater, bivalve mollusks could wreak havoc on Wyoming’s water systems and reservoirs should they make their way into the state.
    Members of the list of aquatic invasive species (AIS), zebra and quagga mussels currently occupy waters in over 30 states, and surround Wyoming on three sides in Utah, Colorado and Nebraska. The nearest infected waters are 50 miles from the Wyoming state line in Utah.
    The mussels were imported to the U.S. on ships traveling from the Black, Aral and Caspian seas in the mid-1980s to the Great Lakes, from which they spread quickly throughout the eastern U.S.
    To prevent their introduction to Wyoming the Wyoming Game and Fish Department (WGFD) has undertaken extensive public education and outreach efforts, as well as working with the Bureau of Reclamation on monitoring in the state’s major waters and the Wyoming Legislature on legislation for mandatory checkpoints and funding for surveillance.
    “After the mussels began to spread downstream it became obvious they were crossing watersheds, and their primary transport was watercraft,” says WGFD Director Steve Ferrell, adding, “In the West the plan was to keep them in the East with an initiative called the 100th Meridian, an effort to keep them from crossing that line.”
    That worked for about 20 years, but in 2007 they were found in the lower Colorado River and Lake Mead between Nevada and Arizona. “After that they moved downstream and began crossing watersheds,” says Ferrell. “The concern for all the states is the impact they have not just on fish and wildlife resources, but on anybody who uses water, from irrigation districts to hydropower to municipal water.”
    Ferrell says the investment in prevention is far better than what would be spent to maintain and manage populations if they were to make it into the state. “Once they establish they’re nearly impossible to eradicate, and they multiply so quickly,” he notes. “They essentially could clog a 30-inch pipe in a short period of time, so it’s a constant maintenance nightmare for water users.”
    Some states estimate the cost of cleaning a single intake tower on a cooling plant at $800,000. “It’s a pricey proposition, once you have them, to continue the operation of the facility that’s affected,” says Ferrell.
    “In the ag water supply, the mussels could cover any hard surface of an irrigation canal, covering the entire bottom and colonizing on top of existing mussels,” says WGFD AIS Coordinator Beth Bear. “That would impede water delivery and clog pipes.”
    The WGFD plan for the invasive mussels includes four steps – prevention, surveillance, containment and eradication.
    “We’ve ramped up our outreach and education to the public, and we’re going to continue to do that with the available resources,” says Ferrell.
    “We’re asking watercraft owners to drain, clean and dry boats for at least five days between waters, and that will stop the transport of mussels and all other aquatic invasive species,” says Bear. “We’re targeting mussels, but it will also catch all the other invasive plants.”
    In addition to education, the other half of prevention is boat inspections. “Most states have a program to inspect watercraft and decontaminate those that need it with a high pressure hot water wash at 140 degrees, which kills them,” says Ferrell.
    Regarding surveillance, Ferrell says there are people looking for the organism in its environment. “They take a sample of water and send it to a lab, and if the larval forms are present they run a DNA test,” he says.
    Bear says they expect to first see the mussels in public use areas.
    In containment, Ferrell says if a population is identified there needs to be an immediate response plan to keep the infected water from spreading.
    The fourth step, eradication, he says is really hard. “The cost of eradication is outrageous, and only one isolated population has been eradicated,” explains Ferrell. “In a big body of water like Buffalo Bill, Boysen or Flaming Gorge, management would be expensive and eradication impossible.”
    Bear notes that if Wyoming’s large reservoirs are infected there’s no way to get rid of the mussels unless the entire water is treated, which would also kill everything else in the reservoir. “Once they’re in it’s a matter of containing the spread,” she says.
    Flaming Gorge Reservoir experienced a near miss in April, when a Wyomingite bought and imported a boat from Arkansas. Before launching it he had it inspected and a live quagga mussel was found and removed. “His awareness and the awareness of the mechanic that inspected the boat allowed us to decontaminate it,” says Ferrell.
    The mussels can live out of water for an extended period of time, depending on air temperature and humidity. Ferrell says they can live up to seven days in Wyoming’s climate, provided it’s not cold enough to freeze.
    Going forward, Ferrell says the department’s working with the Travel, Recreation and Wildlife Committee of the Wyoming Legislature on an interim study. “They were very interested in seeing what we could do to prevent their invasion into Wyoming. They directed us to draft a bill that addresses the plan the WGFD has written,” he notes.
    Bear says that right now invasive aquatic species are covered under the WGFD, state noxious weeds and federal legislation, but nothing covers the whole gamut.
    The WGFD will also finish writing the state’s Invasive Species Management Plan for Aquatic Mussels, which should be finished by the end of the year.
    “Once the mussels are in a body of water, any water user can be impacted, from the sprinkler head on an irrigation pivot to the faucet in your kitchen,” cautions Ferrell.
    “If these mussels come into the state they’ll create a domino effect, causing severe outages,” says Game and Fish Commission member Jerry Galles. “They plug things up and take aquatic habitat fisheries need, as well as fill livestock ponds, drainage systems and irrigation ditches. It’s a state issue, and not just wildlife related.”
    Christy Hemken is assistant editor of the Wyoming Livestock Roundup and can be reached at

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