Dreissena polymorpha
zebra mussel

Zebra mussels were originally found in the Black and Caspian Seas. Today, they are found in the Rhine River, rivers in middle Europe, and in lakes and rivers in the United States, including the Great Lakes.

Zebra Mussels are found mostly in stagnant freshwater. They disperse to new areas during the larvae stage.

Zebra Mussels are filter-feeders. They take water in, filter out the food, and then expel the water from their bodies. They must attach to a solid substance to mature into the adult stage. Once attached to their foundation they remain there for the rest of their lives, sessile. Many zebra mussels colonize with other zebra mussels on the same substrate.

Zebra mussels eat mainly bacteria, blue-green algae, small green algae, and very fine detritus particles, which they capture by filter-feeding. The larvae of the zebra mussels eat mainly algae.

The infestation of zebra mussels into many areas of the world has created a major economic problem. The introduction of zebra mussels to North America is one of the great ecological disasters of our time. Their initial entry was from ship ballast emptied into Lake St. Clair, Michigan. They rapidly spread throughout much of the Great Lakes, then into smaller inland lakes, and most recently into the Mississippi River system. The native mussels in Lake St. Clair are now reported to be completely eliminated. The larval mussels settle in water pipes and grids, impeding the flow of water through these pipes. Sometimes waste from the mussels causes water fouling.

Zebra Mussels were added to freshwater lakes in the Netherlands to help make the water more transparent (they eat the phytoplankton that makes the waters cloudy). Other cities in other countries have done the same.

Zebra Mussels have spread into many freshwater lakes and rivers all over the world. Due to the fact that they reproduce in very high numbers, and because they can live in most freshwater enviroments, they are not in danger of becoming extinct.

Zebra mussels get their name from the zebrated markings on their shells. They are preyed up by certain species of ducks (Tufted Ducks, Pochard, and Scaup), some eels, and crayfish. The part of the Lampsilis covered in the pictures shown is that part of the animal exposed above the substrate. The zebra mussels have gotten inside the valves and prevent them from closing completely.