The zebra mussel is a small freshwater mussel, this species was originally native to the lakes of southern Russia. Since their first appearance in U.S. waters in 1988, zebra mussels have spread to a large number of waterways, including Lake Simcoe in the Great Lakes region and the Mississippi, Cumberland, Ohio, Tennessee, Michigan, Colorado and Arkansas. Unfortunately, the zebra mussel invasion continues. For example, in 2009, the Massachusetts Department of Conservation and Recreation confirmed that zebra mussels had been found in Laurel Lake in the Berkshires. That same year, the Minnesota Department of Natural Resources announced that live zebra mussels had been found in Pelican Lake, Minnesota. This is the first confirmed sighting in the Red River basin, which extends across the international border into the province of Manitoba. In July 2010, the North Dakota Department of Fish and Game confirmed the presence of zebra mussels in the Red River. As recently as 2010, California also reported invasions. In 2011, a mussel invasion led to reduced water supplies during a drought year, worsening water restrictions in the Dallas area. However, it has been accidentally introduced to many other areas and has become an invasive species in many countries around the world. Zebra mussels get their name from a striped pattern commonly seen on their shell, although it is not universally present. They are usually the size of a fingernail, but can reach a maximum length of almost two inches. Zebra mussel shells are D-shaped. Zebra mussels are filter feeders. They remove particles from sediment at the bottom of lakes. Zebra mussels process up to a gallon of water...... middle of paper ......d when transoceanic ships anchor in freshwater ports. They have become an invasive species in North America and, as such, are the target of federal policy aimed at controlling them, for example in the National Invasive Species Act (1996). A common conclusion made by scientists predicts that the zebra mussel will continue to spread. passively, by boat and pleasure craft, to other rivers in North America. Towed boat traffic is the most likely cause of invasion in North America. This spread can be avoided if boaters thoroughly clean and dry their boats and associated equipment before transporting them to new bodies of water. Since no single North American predator or combination of predators has been shown to significantly reduce zebra mussel numbers, such a spread would most likely result in the permanent establishment of zebra mussels in many waterways North Americans..