AQUATIC INVASIVE SPECIES THREATEN WYOMING'S WATERS

by WGFD Director Steve K. Ferrell

Special from the March/April Wyoming Wildlife News

All anglers enjoy a day outdoors catching quality fish.  Likewise, boaters want quality time on the water.  But most importantly, we all care about the health of our ecosystems and the safety and stability of water supplies in Wyoming.

In the coming months, you'll be hearing a lot more about new potential threats to Wyoming's aquatic ecosystems. These threats come from the potential spread of aquatic invasive species to Wyoming's waters. These organisms represent a very real threat to our state because of the ecological, recreational and economic impacts they can have on water, fish, equipment and water delivery systems.  It will be important for all of us--anglers, boaters and water users alike--to work together to prevent the spread of these organisms.

What are aquatic invasive species?

Aquatic invasive species are organisms that are introduced into new ecosystems. Many of these species are harmful to the natural resources and threaten human uses of these resources.  Often called "nuisance" species or "exotic" species, they can attach to equipment, boats and clothing used in the water, and can be transferred on these items from one body of water to another.  Once established, these species can cause significant problems for aquatic ecosystems and the people who use them.

Any plant and animal can be considered an invasive species if it's moved to an ecosystem where it doesn't belong. But the Wyoming Game and Fish Department is focusing its attention on two particular aquatic invasive species that are posing an immediate threat to Wyoming -zebra mussels and the quagga mussels.

Zebra and quagga mussels are freshwater, bivalve mollusks that typically have a dark and white pattern on their shells (hence the name Zebra).  They are non-native species, invading North America from the Black, Aral and Caspian Seas since the late 1980s.  They were most likely transported to Europe and then North American in the ballast water of ocean-going ships. Though separate species, they are very similar in appearance and impact.  In general, these mussels are up to an inch long, and attach to hard surfaces like boats, piers, pipes and other equipment.  They are often found in clusters.  These mussels reproduce quickly - a single female is capable of producing more than 1 million eggs a year. There are no known populations of these mussels in Wyoming to date, but they have rapidly invaded waters across the country and are now present in three of our neighboring states - Colorado, Nebraska and Utah.

Why is WGFD concerned?

Collectively, aquatic invasive species can have tremendous detrimental impacts to things we value-- healthy ecosystems, recreational equipment, and secure water supplies.  The costs associated with dealing with invasive species can be staggering.  Utah estimates that managing quagga mussels could exceed $15 million per year.  North Dakota estimates maintenance and monitoring costs for water intake facilities at $383,000 per intake per year and nearly $800,000 per year for each cooling plant tower.

Heavy infestations of these species can alter aquatic environments by reducing food sources for game fish.  Mussels remove significant amounts of phytoplankton from the water, which in turn are food for larval and juvenile fish, which are in turn food for sport and commercial fisheries.  These species can also reduce oxygen levels in the water, stressing or killing fish.

Another significant impact of zebra and quagga mussels is the effect on recreational opportunity and equipment.  They can clog water intakes on motors, overheating and ruining boat engines.  They can also attach themselves to the hull, propeller, and other areas of the motor, affecting the performance of the watercraft.  

In addition to impacts on anglers and boaters, aquatic invasive species can increase the operating costs of irrigation and drinking water systems, power plants, dam maintenance and industrial processes.  For example, zebra mussels attach to hard surfaces and colonize on structures like those used for irrigation, power, and municipal water treatment plants, reducing pumping capacities and increasing maintenance costs.  Affected municipalities and industries in the Great Lakes area, where zebra mussels are established, spend millions of dollars every year on mussel control.  Those costs are eventually passed on to consumers.

What is being done?

Wyoming needs a comprehensive and cohesive approach to effectively deal with the increasing risks from aquatic invasive species.  The scope and effect of this issue in Wyoming extends beyond Game and Fish and will require cooperation from other agencies and all citizens of our state.  We have been working with other agencies to create a strategy that will likely involve four stages of action:

-Stage one involves educating the public; 

-Stage two focuses on prevention through inspection and boat washing;

-Stage three involves surveillance and monitoring (looking for mussels and veligers in reservoirs); and

-Stage four focuses on eradication once established.

It’s important to understand that the early stages of action, which focus on education and prevention, are much less expensive than the later stages, which involve dealing with these species once they become established in Wyoming.  A recent study from the University of Florida estimated the benefit:cost ratio of prevention at 70:1, compared to a 4:1 ratio for eradication.  So it's critical, from both an economic and ecological perspective, to do everything we can to prevent these species from entering the state.

How can you help?

The best way you can help with this effort is to make sure you aren't spreading invasive species from one body of water to another.  Overland transport on boats, motors, trailers and other watercraft poses the greatest risk for spreading aquatic invasive species, so it’s important to properly care for your equipment. 

Before leaving a body of water, but while on dry land, do the following:  Drain every conceivable space that can hold water, including engines, live wells or ballast tanks or even just the inside of your canoe, kayak or raft.  Clean any and all equipment by removing plants, mud and other debris.  Allow all equipment to thoroughly dry before launching in another body of water.  Desiccation times to ensure that zebra and quagga mussels are not viable depend on air temperature and humidity; but they can remain alive for over 7 days in July.

Overall, these aquatic invasive species are small, but when introduced to a water body, they can have giant consequences.  It's difficult to overstate the impacts an invasion of the zebra or quagga mussel would have on the ecology, economy and culture of Wyoming.  If you are a fisherman, if you enjoy recreational boating or even if you just use water for drinking or irrigation, it's important to understand how dangerous these species are. Do everything you can to keep them from spreading.  Let's keep Wyoming's waters secure.