The Zebra Mussel

Where did the zebra mussel come from?
What have zebra mussels done elsewhere?
What might zebra mussels do to Edinboro Lake?
How might this invasive species spread?
What can people do?

Zebra mussels (Dreissona polymorpha) are small mollusks approximately one inch in size and native to the Caspian Sea. They were first discovered in the U.S. in Lake St. Clair, between Lakes Huron and Erie. It is thought that they were introduced from the ballast of water of an oceangoing ship. Today they are likewise believed to travel on the hulls of unsuspecting fishing and recreational boats.

In Lake Erie the density level of zebra mussels can be 560 or more per square foot. At this population density, zebra mussels can clog water pipes, underwater machinery, and even boat motors.

Zebra mussels disrupt the aquatic food chain by removing most phytoplankton (tiny, free-floating plants) and zooplankton (plankton composed of animals) from water. This causes a dangerous disruption in the aquatic food chain. Their dense population often overtakes native mussels and other species. Native clams have disappeared from Western Lake Erie due to these mussels. Due to their filtering efficiency, zebra mussels can have high concentrations of toxins, which can pass to many waterfowl that feed on them.

Recently, zebra mussels were found in Edinboro Lake, the first inland lake in northwestern PA to be inhabited by these organisms. Because Edinboro Lake is a much smaller than Lake Erie, the effects of zebra mussel are expected to be profound. The current plan is to try to contain the mussels in Edinboro Lake. If they are not contained, then they may pass into Conneautee Creek, then French Creek and then into the Allegheny, Ohio and Mississippi Rivers to further their damage to Pennsylvania's waterways and aquatic industry and recreation.

There is considerable concern over zebra mussel contamination in French Creek because it represents one of the last refuges for many rare and endangered species. The Western Pennsylvania Conservancy lists the stream as having global significance in its near-intact pre-Colonization stream ecosystem. Almost thirty species of mussels inhabit French Creek and two, the Northern Riffleshell and the Clubshell mussel, are endangered species

Residents and visitors of Pennsylvania can help prevent the spread of this invasive species by taking extreme care when transporting boats from one lake to another inland lake. For a complete list of tips and precautions and more information on zebra mussels, please visit http://www.great-lakes.net/envt/flora-fauna/invasive/zebra.html.