NOTICE - Aquatic nuisance species, or ANS, are defined as any nonindigenous (not native) aquatic species of plant or animal that has a negative effect on native species or the ecological stability of waters. Negative effects may lead to a decrease in sportfish and native species numbers or other negative impacts on desirable aquatic life which can lead to commercial and/or recreational loss as well as the possible complete elimination of native species. At times, health issues might also be an area of concern. ANS can take a variety of forms, from plants such as water milfoil, that can clog canals and impede water delivery, to quagga mussels that can clog water intake pipes, to New Zealand mudsnails, which replace native invertebrates that are an essential food source for desirable fishes.

Invasive Species Cost Everyone

Control, or at least reduction, of ANS costs millions of dollars a year. According to a University of Notre Dame study, zebra and quagga mussels cost the Great Lakes regional economy at least $200 million a year. Leonard Willett, Bureau of Reclamation quagga mussel coordinator for the lower Colorado River Dams, estimates that the maintenance bill for clogged hydroelectric cooling pipes in Hoover Dam could reach $1 million per year. Eradicating the northern pike from Davis Lake in California has cost that state over $20 million to date. Keeping water delivery canals in Southern California free of water hyacinth costs that state millions of dollars annually. In addition to maintenance costs, there's also revenue lost from decreased recreational fishing opportunities.

ANS Damage Fisheries

Nevada's waters have already been significantly damaged by the illegal transfer and release of ANS. Introduced bullfrogs, being large and aggressive, have displaced native frog species such as the leopard frog. Nonnative crayfish have been introduced into streams and springs throughout southern Nevada, negatively impacting native fish and amphibian species. Comins Lake, near Ely, was a trophy trout fishery several years ago. It was not uncommon to catch several rainbow over 5-pounds in one outing. Illegally introduced northern pike increased in size and total numbers until they "took over" the lake, decimating the trout and largemouth bass. Quagga and zebra mussels filter water, straining zooplankton and phytoplankton which form the base of the food chain in lakes and ponds; individual mussels can filter up to one liter of water per day. Large decreases in plankton abundance alters the food chain in lakes and reservoirs to the detriment of sport and native fish species. Mussel waste products increase the occurrence of toxic blue-green algae blooms and increased water clarity can also increase the abundance of undesirable aquatic plants. The illegal release of aquarium fish has been the single greatest threat to Nevada's sensitive native fishes in our many warmwater spring systems. Once ANS are released and established, removal or control can be virtually impossible, permanently and negatively impacting our aquatic systems throughout the state.

What Can You Do? Difficulties of Removal and Cleanup

Control of ANS varies with the species, but once established, unwanted species are difficult, if not impossible, to get rid of. Mechanical means of removal, such as cleaning the irrigation ditches of southern California, is both time consuming and expensive. Chemical treatment is the most common procedure for unwanted fish removal. Among the options being investigated for control of invasive mussels include using bacteria that targets the mussels. The use of chemicals, filters and ultraviolet light are other control methods.

What Can You Do?

Boaters

• Remove any visible mud, hitchhiking plants and animals and place them in the trash before transporting equipment.
• Rinse boat and equipment thoroughly, including draining all lake or river water before transporting.
• Clean and dry anything that comes into contact with water (boats, trailers, equipment, clothing, dogs, etc.)
• Flush jet ski, boat or bilge/ballast with hot sudsy water or 5% bleach solution.
• Air-dry boat, personal watercraft or other equipment for at least 5-days before moving to a new body of water.
• Never release plants, fish or animals back into a system, unless they are from that body of water.

Anglers

• Rinse mud and debris from waders, boots and other gear after use, and let it dry as long as possible.
• Do not reuse bait or transfer bait between bodies of water.
• Follow regulations regarding live bait; many invasive species problems are the result of bait releases.
• Never release plants, fish or animals back into a system, unless they are from that body of water.

Aquarium Owners

• Do not release unwanted aquarium plants, animals or fish into Nevada waters. Aquarium releases are a major problem in many Nevada waters.