Zebra mussels have been a major problem in Midwestern and Great Lakes waterways for more than three decades when the invasive species was brought over by ships from the Black Sea in eastern Europe. Officials say the mussels were first found in South Dakota in 2014 and have recently spread to new areas.
Mike Greiner is the aquatic invasive species coordinator for the South Dakota Game, Fish and Parks.
Greiner says zebra mussels spread in the summer months when waters are regularly above 50 degrees.
He says zebra mussels spread quickly. He says the first mussel was discovered in November of 2014 in Lewis and Clark lake and by summer the infestation had spread throughout the lake and connected waterbodies.
Greiner says mussels have recently been found in the Lake Francis Case Reservoir.
“Basically from below Big Bend Dam almost throughout the entire reservoir. The lowest would be at the Peace Creek Lakeside Recreation Area. So that’s about 10, 11 miles upstream from fort Randall Dam,” says Greiner.
Greiner says they have equipment deployed to monitor the spread of the mussels for the remainder of the season to determine the extent of their spread. He says the environmental impacts of the mussel vary greatly between bodies of water, but their long-term presence in the Missouri River and connected water ways gives a better look at the potential impacts in South Dakota.
“Some of the effects that we’ve seen from zebra, and their cousin the quagga mussel, have been in in the U.S. for over 30 years now so there’s a lot of examples of what you can expect to see,” says Greiner.
Greiner says the mussels are more likely to affect infrastructure than fisheries but can have severe environmental impacts. He says they are highly efficient filter feeders and can disrupt the food web and over filter waterways causing a disruptive overgrowth of aquatic vegetation.
He says there are promising developments to help eradicate zebra mussels, but no options exist that are consistently effective, especially in larger water ways.
Greiner says the best way to prevent the spread of zebra mussels to outside waterways is to follow established regulations regarding cleaning and drying boats before using them between different bodies of water.