Zebra Mussels, which are native to Eurasia, more specifically the Balkans, Poland, and the former Soviet Union, were first introduced to North America in 1988 in Lake St. Clair, a small lake between Lakes Huron and Eerie. Since then, they have spread throughout the Great Lakes and various rivers that flow by. The zebra mussels get their name from their striped patterns on their shells, and range from fingernail size to nearly two inches long. On average a female can begin to reproduce when it is two years old and can produce up to a million eggs in a year. Sheer numbers and the fact that they are small allow the mussels to spread very quickly, especially since young zebra mussels are able to swim freely.

However, with so many of these zebra mussels and no natural predator in the area, the mussels out-compete the native species and eat all the food available. Also, as the mussels become older, they attach themselves to hard surfaces, which include boats, other mollusks, turtles, and water-intake pipes. This can clog pipes and kill the other animals. Slowly overtime, some animals have adapted to the increase in these mollusks and have begun to feed the new food source. However, this is not nearly enough to keep the population of zebra mussels in check. Tons of money are spent unclogging pipes and clearing out sharp shells from shores and beaches every year. While the effects of the zebra mussels are devastating, it also increased the number of certain fishes that have begun to feed on the mollusks and underwater plantation, resulting in a large change in the ecosystems. It will be interesting to see if perhaps in the near future, there will be enough predators to keep the zebra mussels to spread.