But migration of the zebra mussels to North America is what has been the cause of concern. Zebra Mussels were first discovered in North America in 1988, more specifically at Lake St. Clair in Canada. By 1990, the mussels were found in all of the Great Lakes. The probable cause for the method of introduction of this species to North America is most likely due to ballast water from cargo ships from the Atlantic. Another form of introduction within the United States is due to private boats who move from lake to lake for leisure.
Native mussels play an important role in nutrient cycline and sediment mixing.
This could seriously affect the ecology of the Mississippi River system. Information from Europe suggests that zebra mussels dominate over native mussels by interfering with feeding, growth, locomotion, respiration, and reproduction. Other parties have other reasons for removing or protecting against the zebra mussels. Zebra mussels colonize pipes, which constricts flow. Navigational and recreational boating can be affected by drag due to mussel attachment.