Zebra Mussel - Dreissena polymorpha




Since Zebra Mussels are filter feeders, their presence in an ecosystem creates water clarity and decreases food supply for other organisms around them. Zebra Mussels generally form colonies that cause an even greater depletion of resources. More info on this can be seen on the adaptation page.

The location of where they live also affects humans. They used the amazing strength of their byssal threads to attach to many different surfaces. Zebra Mussels are known to infest raw water intake pipes and power plant pipes. Since they are generally found in large numbers, they are known to limit water flow causing a large financial impact. They also collect onto the bottom of boat hulls and create drag, and collect on docks, which causes deterioration. The amount of Zebra Mussels usually exceeds 250,000 individuals per square meter. They can cause corrosion of steel and concrete when so many are attached, which affects structural reliability of facilities using these materials. They also have had a large economic impact already.

 Many power plants and water users have had to spend millions of dollars cleaning out zebra mussels from their facilities. More money also has been spent on revamping facilities with special devices to keep zebra mussels out and to monitor for their presence. The extremely high costs of these procedures then gets passed along to the consumers.

Since there are so many Zebra Mussels, they have the ability to attach to native mussels. This leads to smothering them and killing them off. This is one of the most threatening impacts. As many as 10,000 zebra mussels have attached to a single native mussel.  Our natives have all but disappeared in Lake St.Clair and the western basin of Lake Erie.  Survival rates of native unionoid mussel in the Mississippi River, Minnesota have been shown to decrease significantly with the increase in zebra mussel numbers. More interesting facts about Zebra Mussels can be seen here!

Zebra mussels are filtering the Great Lakes at an increasingly fast rate, causing the lakes to become very clear. Most people assume that this increased visibility in the water must mean the water is cleaner, but all they have done is filter out all the algae which normally would be food for native microscopic organisms.

Zebra mussels do not have many natural predators in North America, but it has been documented that several species of fish and diving ducks have been known to eat them. Predation and resource abundance can strongly affect the structure and dynamics of animal populations within aquatic ecosystems.