The USGS Nonindigenous Aquatic Species database contains spatially referenced biogeographic accounts of exotic and native transplant freshwater species in the U.S. and its island territories. NAS specimen occurrences are verified by trained staff and come from literature, museums, state and federal surveys, and public sighting reports. The general public can view and download occurrence information from the national view of the NAS database found here.
The MAPAIS regional view of the NAS database provides a subset view of the national database to nonindigenous aquatic species found in the Mid-Atlantic region states. A border line of the MAPAIS states is provided on the map along with a line for the states bordering the region.