Zebra Mussels look like small clams with a yellowish or brown “D” shaped shell, usually with alternating dark and light colored stripes. They can be up to two inches long, but most are under an inch. They grow rapidly and mature within a year and reproduce prolifically. An adult female can produce 30,000-100,000 eggs a year. Like other species of mussels, they grow in clusters.

Zebra mussels were accidentally brought to North America, possibly on the hulls of water vessels from Europe. Their free-swimming, nearly invisible larvae, called veligers, may have also been discharged from the ballast water of transoceanic ships. Zebra mussels have plagued Europe for centuries. They have spread to many lakes and rivers in both the US and Canada.

Within two to three weeks, the veligers settle and attach by strong byssus threads to hard surfaces such as rocks, wood, glass, fiberglass, metal, gravel, and native mussels. They are the only mollusk that can firmly attach itself to solid objects. They grow best in areas of free-flowing water where they can filter out large quantities of plankton. Colonies of Zebra mussels may accumulate and clog water-intake pipes and screens of drinking water facilities, industrial facilities, power plants, irrigation pipes, and cooling systems of boat engines.

They are prodigious eaters; they filter out nearly all the phytoplankton and small zooplankton in the 15-40 micrometer size. This doesn’t sound like much, but it has the effect of removing most of the food for microscopic zooplankton and filter feeders, which support larval and juvenile fishes and other animals. The Zebra mussel can effectively starve the native populations of infested lakes and rivers. Once the Zebra mussel arrives, a lakes that are full of phytoplankton soon after the lakes will be devoid of the algae.

Clogging pipes and devouring the food supply are not the only threat the Zebra mussel poses. They present a health hazard by increasing human and wildlife exposure to organic pollutants such as PCBs and PAHs. The Zebra mussel can accumulate the pollutants in their tissues in concentrations 300,000 times greater than in the environment. They deposit these pollutants as pseudofeces, loose pellets of mucous mixed with particulate matter that they filter from the water. Scavenging animals that eat the pseudofeces may pass these pollutants up the food chain. If these mussels coat the beaches, their sharp edges cut the feet of swimmers.

What to do if you find a Zebra Mussel:

ü  Note the date and precise location where the mussel or its shell was found.

ü  Take the mussel (several if possible) with you. Store them in rubbing alcohol.

ü  Do not throw them back in the water!!!

ü  Immediately contact your states DNR (department of Natural Resources).

Help stop the spread of Zebra Mussels

ü  Drain and clean all water from bait buckets and live wells.

ü  Dispose of all bait in the trash.

ü  Wash the hull thoroughly.

ü  Remove all weeds from boats and trailers.

ü  Check boats and motors for Zebra Mussels

ü  Dry boats and trailers completely between launches. (Especially before launching into different fresh waters. If you can wait five days between launches into different fresh waters.)