Another Great Year For The Iowa Great Lakes

This boat hoist removed from Clear Lake in the fall has Zebra Mussels on the underside of the horizontal members. The zebra mussel outbreak at Clear Lake began only three years ago.

SAMPLER PLATES

This past spring the Department of Natural Resources installed sampler plates below navigation buoys near boat ramps on the Iowa Great Lakes. These sampler plates consist of multiple metal plates spaced close together to provide zebra mussels a place to attach their bodies. These sampler plates have been pulled from the lakes in the past few weeks and did not provide any sign of zebra mussels. Although this is not a comprehensive test, it does provide some initial good news.

DOCK & HOIST REMOVAL

When the docks and hoists are removed from the lakes this fall we will have a more wide spread chance to see if zebra mussels arrived this summer. The zebras that hitched a ride on visiting boats could have attached themselves to dock posts, swim ladders, and hoists. These invasive critters prefer dark places so they are more likely to be found on the underside of horizontal members.

So look at dock posts, swim ladders, and hoists after they are removed from the lake to see if any zebra mussels have begun growing there. To help with identification detailed pictures of EWM and ZM's are available on the Water Safety Council website www.watersafetycouncil.org -- click on Aquatic Invasive Species. If you think you have spotted zebra mussels a call to the DNR Fish Hatchery in Spirit Lake, 712/ 336-1840 will provide expert help with the proper identification.

Why Are Eurasian Watermilfoil and Zebra Mussels a Concern?

Eurasian watermilfoil is not a native plant to the United States. With no natural enemies, it grows very quickly. In a short time, it can create a thick mat of weeds that makes it difficult to fish, swim or boat. In larger bodies of water, there is no effective way to eliminate them, so the best way to deal with Eurasian milfoil is to prevent them from gaining a foothold in our lakes in the first place.

Zebra mussels are not a native mussel to the United States. For this reason, they also grow very quickly with no effective way to stop their rapid growth. Young adult zebra mussels are about the size of your fingernail and have the characteristic brown and white zebra like stripes. Their sharp edges can cut swimmers feet so they are dangerous on swim ladders and dock posts. Because zebra mussels multiply so rapidly, they can block the water intake pipes that provide drinking water to most Dickinson County residents.