Invasive species are alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health. Alien species are, with respect to a particular ecosystem, any species, including its seeds, eggs, spores or other biological material capable of propagating that species, that is not native to that ecosystem (Office of the President of the Unites States, 1999). Aquatic invasive species are a sub-set of invasive species that impact aquatic ecosystems. Based on the definition from the federal Non-indigenous Aquatic Nuisance Prevention and Control Act of 1990, aquatic invasive species are defined in this document as non-native species that threaten the diversity or abundance of native species, the ecological stability of infested waters, human health and safety, or commercial, agricultural, aquacultural, or recreational activities dependent on such waters. Article 1, Section 27 of the Pennsylvania Constitution states that the people have a right to clean air, pure water, and to the preservation of the natural, scenic, historic and esthetic values of the environment. Pennsylvania's public natural resources are the common property of all the people, including generations yet to come. As trustee of these resources, the Commonwealth shall conserve and maintain them for the benefit of all the people. The value of Pennsylvania’s aquatic resources demands a comprehensive response to the threat posed by aquatic invasive species. The Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990, amended by the National Invasive Species Act of 1996, calls for the development of state and regional AIS management plans. Gathering input from Pennsylvania representatives of state and federal agencies, industry, nongovernmental organizations and other stakeholders, and using guidance from the federal Aquatic Nuisance Species Task Force, this plan has been developed to coherently address AIS issues across Pennsylvania. This plan is to be implemented under the auspices of the Governor’s Pennsylvania Invasive Species Council (PISC).