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Water: Habitat Protection

Invasive Species

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Invasive species means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health. Invasive species are one of the largest threats to our terrestrial, coastal and freshwater ecosystems, as well as being a major global concern. Invasive species can affect aquatic ecosystems directly or by affecting the land in ways that harm aquatic ecosystems. Invasive species represent the second leading cause of species extinction and loss of biodiversity in aquatic environments worldwide. They also result in considerable economic effects through direct economic losses and management/control costs, while dramatically altering ecosystems supporting commercial and recreational activities. Effects on aquatic ecosystems result in decreased native populations, modified water tables, changes in run-off dynamics and fire frequency, among other alterations. These ecological changes in turn impact many recreational and commercial activities dependent on aquatic ecosystems. Common sources of aquatic invasive species introduction include ballast water, hull fouling, aquaculture escapes, and accidental and/or intentional introductions, among others.


Corbicula fluminea. Often called the Asian clam, this small mollusk can clog intake pipes for cooling water.

Vessels and Invasive Species

Vessels can be a significant pathway for the introduction or spread of invasive species through the discharge of ballast water containing invasive species or the transport of invasive species that have accumulated as biofouling on ships' hulls. EPA and its federal partners, such as the U.S. Coast Guard, are working together and using their authorities to help address the environmental and economic threats associated with ship-related introductions of invasive species. For information on EPA activities under the Clean Water Act addressing this issue visit the EPA Vessel Discharges, and EPA Clean Boating Act webpages. For information on U.S. Coast Guard activities under their statutory authorities, visit the U.S. Coast Guard Aquatic Nuisance Species webpage.

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