The rate of species introductions has increased dramatically in the past few centuries, as a result of human activities, such as global exploration, trade, and colonization. Species evolve and disperse naturally, but at a much slower rate without human influence.

Species introduction happens both intentionally and unintentionally. In the late 1800s Federal funding helped to introduce carp to the United States from Europe for their presumed culinary excellence and angling potential. By contrast, ocean going vessels from Europe accidentally introduced the zebra mussel to North America by dumping contaminated ballast water into the Great Lakes.

More recently, zerba mussels have dispersed into inland lakes, largely through the inter-lake movement of recreational and fishing boats. Mussels attach to boats, nets, docks, swim platforms, boat lifts, and can be moved on any of these objects. They also can attach to aquatic plants, making it critical to remove all aquatic vegetation before leaving a lake. Microscopic mussel larvae may be carried in water contained in bait buckets, bilges or any other water moved from an infested lake or river. Click here to learn more.