Oregon Sea Grant

Nonnative species are altering freshwater and marine ecosystems in the Pacific Northwest, and more species are introduced every year. This identification guide has been developed as a tool to help watershed councils and other community-based groups increase their understanding of aquatic invasive species (AIS), and to initiate monitoring efforts for species of particular concern to their watersheds. It provides background information and key identification characteristics of many aquatic invaders that are already established or likely to become established in the Pacific Northwest. Ultimately, greater awareness of the pathways that spread aquatic invasive species to new regions can help prevent their introduction, and monitoring efforts can help identify and respond to new invasions before they become a problem.