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Mini Monsters "Musseling" into Missouri

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Published on: Aug. 2, 1995

Last revision: Oct. 20, 2010

turbid rivers, including the Cumberland and the Tennessee have self-sustaining populations.

As of the spring of this year, zebra mussels in Missouri have been limited to the Mississippi River, but that's only the vanguard of the invasion. "Zebra mussels are capable of colonizing everywhere in Missouri," said Al Buchanan, an environmental services biologist with the Conservation Department. "I'm almost certain they'll be in Lake of the Ozarks this year; there's so much boat traffic, so many accesses."

Zebra mussels are likely to thrive in the Lake of the Ozarks, Buchanan said, and the population will provide a constant feed of larvae through the dam and downstream. They are also likely to be spread by boats to other reservoirs.

"Predicting what will happen to fish populations is sheer speculation,"Buchanan said. "High numbers of zebra mussels could affect shad, which also feed on plankton, and we don't know what will happen with predator species or plankton-eating paddlefish."

Lots of other questions remain unanswerable. Will zebra mussels establish themselves in the Current, Meramec, Jack's Fork, Eleven Point or North Fork rivers?

What about fish hatcheries? "It would be impossible to stock fish from an infested hatchery," Cindy Borgwordt, Fisheries Division information officer said, "because of the danger of contamination of new waters."

Already, the zebra mussel threat has forced the Conservation Department to close Hunnewell Lake, source of the Hunnewell hatchery's water, to privately owned boats to reduce the threat of zebra mussel contamination from craft that have recently been in the Mississippi River.

To keep Lake Sherwood, near St. Louis, free of zebra mussels, the lake association has plans to install a wash rack at the lake's single access and will require all boats to be washed before being launched.

Other states have taken more stringent measures. Minnesota, for example, has set up highway check stations that stop boaters and inspect their boats. People found transporting zebra mussels, water milfoil and other aquatic troublemakers are being fined.

Because the invasion is just happening now and no one can predict its course, management options in Missouri are limited. This summer, the Conservation Department posted zebra mussel alert posters at all water access sites and has produced id cards and brochures about zebra mussels. Posters, id cards and brochures are available free by writing to "Zebra Mussel," Missouri Conservation Department, P.O. Box 180, Jefferson City, 65102-0180.

What else might be done? A few fish species - drum, suckers, redear sunfish -will eat zebra mussels, as will some diving ducks, but these native species are unlikely to make much of a dent in the population.

A new exotic species, the round goby, has followed the zebra mussels into the Great Lakes and appears to have taken hold in southern Lake Michigan. The goby's large mouth and peg-like teeth suit it well for feeding on zebra mussels. The bottom dwelling fish seldom reach 8 inches in length, but they may provide food for gamefish.

Researchers are also testing to see whether zebra mussels mixed with wood chips and other materials will compost. No other prominent economic uses for zebra mussels loom on the horizon, but if you can figure out a good use for them, it will likely enrich you more than could the lottery.

According to Borgwordt, the best approach for Missourians right now is to conscientiously work to stop the spread of zebra mussels in order to buy time for a control method to be developed.

With our moderate temperatures and fertile waters, Missouri seems primed for an explosion of zebra mussels. It could be in 3 years, 5 years, 10 years or next year.

What effect zebra mussels will have on our ecosystems and environment is anybody's guess. They may change the aquascape entirely, or their populations might explode, crash and then settle into a more moderate persence among Missouri's biota.

Not knowing makes facing the threat even harder.

It's like waiting for a hurricane that's coming, but you don't know how severe it will be or where it will hit the hardest. After you've done what you can to protect yourself, all that's left is to hunker down and try to ride it out

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