Zebra mussels originated in the Caspian sea, but began to spread throughout Europe after the creation of canals in the 1700s and 1800s. In 1985, they were brought to the United States after a ship from Europe released its ballast, and within one year, it had colonized the entirety of Lake Erie, and then went on to colonize all the great lakes. By 1992, it could be found as far south a St. Louis. Zebra mussles cause great damage wherever they are introduced because of their filter feeding and colonization on native species (8)
Each mussels filters a quart of water every day, and an entire colony could filter an entire lake or river each day (9). Everything it filters is removed, which means that vast amounts of plankton and algae are removed. Other small fish depend on these plankton, which causes their populations to whither, which in turn hurts the populations of larger fish (8). Zebra mussels also have a habit of colonizing on top of other creatures, including native mussels, clams, crayfish, and turtles. This keeps these creatures from being able to eat, breathe, reproduce, or move (9). Wherever they colonize, water clarity is greatly improved (8).