Zebra mussels have now found their way to the United States originating in the Caspian Sea and sought habitation, originally, in Lake St. Claire when ballast water brought them here. From there, zebra mussels spread and wreaked havoc on the environments and its biodiversity, particularly in Presque Isle. Zebra mussels filter zooplankton and phytoplankton, making the water clearer, but not cleaner. They have had a negative impact on the existence of clams, walleye and many other organisms. To preserve the biodiversity of Presque Isle, zebra mussels must be killed and controlled. Different methods that can be used to achieve this are chlorination, poison, scraping, etc. What are invasive species? Invasive species are non-native organisms that occupy habitats and disrupt the natural ecological cycles of the habitat. They threaten the biodiversity of an ecosystem and are biological pollutants. Invasive species introduced into new habitats usually maximize their reproduction in their new home and crowd out native species. Their lack of natural predators in their new community allows for proliferation, growth and expansion as a result of their abundant food supply. Once established, invasive species can rarely be eliminated because their new habitat is conducive to their survival. Introduction to Zebra Mussels Zebra mussels also known as Dreissena polymorpha are small freshwater molluscs that have invaded American rivers and lakes. They came from the Balkans, Poland and the Soviet Union. In 1988 they were found in a small body of water connecting Lake Huron and Lake Erie, known as Lake St. Clair. Biologists believe that in European ports, in the ballast water of a ship, in the center of paper, the optimal temperature of zebra mussels can influence their reproductive cycle. When water temperatures reach about 50°F, zebra mussels are breeding in Lake Erie. The eggs are fertilized when both eggs and sperm are released into the water, which then develop into free-floating larvae called veligers. The larvae are carried by water currents, which allows them to expand their distribution. For approximately 10-15 days the larvae are in the planktonic stage. After this stage, veligers seek out an attachment point and attach themselves using elastic fibers known as byssal threads. The point at which mussels begin to form their shells is known as the sedimentation stage. If the water temperature is heated beyond the optimal temperature, the zebra mussels will be in anaerobic conditions and their reproduction process will be interrupted..