What is a zebra mussle?

Answer 1

The zebra mussel (scientific name Dreissena polymorpha) is a highly invasive freshwater bivalve (like a clam), originally from the Caspian Sea (the world's largest lake) in Asia Minor, just north of Iran. They are called zebra mussels because of a distinct striped pattern on their shells. It grows to the size of about a thumbnail, but they can grow in very large densities. They have observed millions of these mussels per square meter in some places. In established populations, which is what happens in most places where it has invaded, they can be devastating to the environment and also a severe economic and aesthetic problem. Large populations can be very efficient at removing nutrients from the water, which may leave little for other organisms in the ecosystem to feed on. Because they also attach to things, you might find them encrusting rocks, piers, boats, pipes, and pretty much anything else in the water that provides a nice firm place for them to settle on. There is no known way to effectively get rid of them once they are established, so they will usually result in high costs to constantly remove them from docks, pilings, boats, water intake pipes, etc. Here is a webpage where you can find sources for other information on zebra mussels: http://www.invasivespeciesinfo.gov/aquatics/zebramussel.shtml