Posted by BOB on November 20, 2004

Q: IN NORTHEAST OHIO, IN SOME OF OUR DEEPER RESEVIORS,WE HAVE AN OVER POPULATION OFF FRESSWATER CLAMMS. BOTH LAKES ARE LOSING THE WEED BASE AND RESOLTING IN LOW FORAGE COUNTS. WHEN FALL LET DOWN OCCURS YOU REALLY NOTTICE THEM STUCK TO EVERYTHING. EVEN SOME OF THE FISH HAVE SORES. WILL THE WEEDS COME BACK?WILL THE CLAMS DIE?ANY INFO WOULD BE HELPFUL THANK YOU! BOB

A: It sounds as though you have Zebra Mussels (these are an introduced clam) as these are definitely common in some of the Great Lakes now and other nearby bodies of water. Take a look at this unit and see if the picture of this clam is like what you're seeing. www.enaturalist.org

Zebra Mussel numbers can be enormous and they are able to make a difference in water quality by straining out microscopic plants to feed. Lakes inhabited by large numbers of these clams usually become very clear. The activity of the clams shouldn't affect the larger plants however, just the small, floating ones. There may be a couple of things going on in your lakes and the clams are only part of the problem. I'll bet the Ohio Dept of Conservation can help you understand what is going on. Thanks for your question.

John Wiessinger ( November 23, 2004)