Alien species invade aquatic ecosystems through both intentional and accidental means. The voluntary introduction, if performed at all, is usually monitored by professionals who have made a risk assessment. Accidental incursion is more difficult to control and poses a potentially grave threat if left unchecked or undetected.Nonindigenous Fresh Water Organisms focuses on this infringement in North American aquatic ecosystems. The 31 chapters measure the devastating ecological, and sometimes economic, impact caused by the encroachment of immigrant species. The book includes case studies such as the Zebra mussel, which arrived in the Laurentian Great Lakes via the ballast of a foreign ship.There is a section for each pathway of introduction, which includes a chapter devoted to its North American history and an analysis of the potential harm caused by further intrusion.
The final portion of the book is devoted to a prediction methodology for the success or failure of an introduction. The chapter on risk assessment is especially useful for the planning of a voluntary introduction.