Nonindigenous Aquatic Species (NAS)

The Nonindigenous Aquatic Species Program neatly parallels several major directives of the 1999 Executive Order on Invasive Species by offering a relevant program to detect, monitor, conduct research and promote public education on invasive species.   In addition it meets a science priority of the USGS by determining the status of  biological resources in aquatic systems. An expansive spatial database underlies the NAS program, which was created in 1978 and continues to be updated and revised. It supports the underlying role of the NAS program, which is to provide a continual national assessment of the status and distribution of nonindigenous aquatic species.

The NAS database functions as a repository and central clearinghouse for occurrence information from across the country.  It contains locality information on more than 1100 species introduced as early as 1850.  Vertebrates, invertebrates, algae and vascular plants are tracked. Taxa include foreign species as well as those native to North America that have been transported outside of their natural range. Locality data is obtained from many sources including the literature, state, federal and local monitoring programs, museum accessions, on-line databases, professional communications and reporting forms.  Before inclusion in the database, records are critically reviewed then geographically referenced to the finest USGS hydrologic unit in order to correlate locality data with river drainage. USGS hydrologic units are commonly employed by natural resource agencies for referencing many types of environmental data, physical as well as biological, and implemented for management at the watershed level.

Program Goals

• Develop and provide an accurate ongoing assessment of the status and distribution of nonindigenous aquatic species nationwide.
   
• Identify geographic gaps in knowledge of the distribution of introduced aquatic organisms.
   
• Gain an understanding of the scope and scale of aquatic introductions in the United States.

The website provides immediate access to new occurrence records through a real-time interface with the NAS database. Website users can perform automatic queries to obtain lists of species according to state or hydrologic basin of interest. Fact sheets, distribution maps and news on new occurrences are continually posted and updated.  Staff may be contacted for specific data, custom products and reports. The NAS website also provides information on reports and meetings and links to relevant sites.

A Few Facts from the NAS Database

• Nonindigenous species have been recorded from nearly every aquatic system in the United States.
   
• In just five years, from 1988-1993, the zebra mussel spread to waters of 20 states. Currently they have been detected in 190 lakes that have no connection to the Great Lakes or to inland waterways.
   
• Introduced through the aquarium trade to seven states, the snail, Melanoides tuberculata, has been found carrying parasites fatal to native fish species in Texas.
   
• One of the nation's top problem aquatic weeds, hydrilla, currently infests 179 drainages in 16 states.
   
• More than 500 fish species have been introduced in the U.S., one-third are foreign, the remaining are native species transported outside of their natural range.

Program Staff

Jim Williams Ph.D. Branch Chief
Amy Benson Fisheries Biologist
Pam Fuller Biologist
Colette Jacono Botanist