Some of the plants and animals in the Bay watershed are not native, but have been introduced either intentionally for agriculture or aesthetic reasons, or accidentally through ship ballast water or unintentional releases. Invasive non-native species in the Chesapeake Bay include phragmites, purple loosestrife, the water chestnut, Asiatic clam, rapa whelk, tiger mosquito, mute swan, nutria, and brown trout.

For more information about invasive species in the Chesapeake Bay, please see the links below:

Maryland Sea Grant College has produced a series of very informative videos and fact sheets entitled "Exotics in the Chesapeake." The Chesapeake Bay Program Invasive Species Workgroup has identified phragmites, the mute swan, purple loosestrife, nutria, the water chestnut and the zebra mussel as invasive species that cause “significant damage” to the Bay's aquatic ecosystem.They are now developing management plans to address the damage that these species have caused and the control of these species in the future.

The Chesapeake Bay Program’s 1993 report, Chesapeake Bay Policy for the Introduction of Non-Indigenous Aquatic Species lays out the official policy on introductions of non-native species for the Chesapeake Bay Program and the states in the Chesapeake Bay basin.

The Aquatic Nuisance Species (ANS) Task Force has recently formed a Mid-Atlantic Regional Panel (MARP) to help prevent the further introduction and distribution of aquatic invasive species. Information on the MARP is not yet available on the web, however the ANS Task Force website is a good source of information about aquatic invasive species. Please stay posted for updates on MARP.