U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2012–3100

September 2012

The National Nonindigenous Aquatic Species Program

Printed on recycled paper

The U.S. Geological Survey (USGS) 

Nonindigenous Aquatic Species (NAS) Program 

monitors, analyzes, and records sightings of 

non-native (introduced) aquatic species throughout the United States. The program is based at the 

USGS Southeast Ecological Science Center in 

Gainesville, Florida.

The initiative to maintain scientific 

information on nationwide occurrences of 

non-native aquatic species began with the Aquatic 

Nuisance Species Task Force, a group created 

by Congress in 1990 to address the need for this 

type of information by natural resource managers. Since then, the NAS program has maintained 

the database as a clearinghouse of information for 

confirmed sightings of non-native aquatic species 

throughout the Nation. The program also produces 

email alerts, maps, summary graphs, publications, 

and other information products to support natural 

resource managers.

The NAS Database in a Nutshell

The NAS database includes records of 

aquatic vertebrates and invertebrates occurring 

outside of their native range. It is freely accessible at a public website (http://nas.er.usgs.gov), 

where users can query the database to view current 

distributions. 

The NAS database encompasses aquatic 

ecosystems (wetlands, lakes, rivers, estuaries, and 

coastlines) throughout the U.S. and its territories. 

The database contains records of more than 1,100 

species dating back to the year 1850, and new 

records are continuously added by NAS program 

staff. The database also offers a searchable reference database on non-native aquatic species, 

factsheets on individual species, distribution maps, 

and new location notices.

Maps produced from the database are widely 

used in scientific talks, publications, and web 

pages, as well as by television, internet, and 

printed news outlets. 

Management & Policy Uses

Risk Analysis

• The U.S. Army Corps of Engineers used NAS to examine the 

risk of non-native species introduction across watershed connections to help prioritize which connections to sever and which to 

monitor.

• The U.S. Forest Service used the database to identify infested 

source waters, thereby lowering the risk of unintentionally 

spreading non-native species while airdropping water drawn from 

natural sources, such as lakes and ponds, to fight fires.

Monitoring and Prevention

• Data and alerts are used by natural resource agencies to determine 

where to focus monitoring efforts.

• Federal and nongovernmental partners have prepared field guides 

for early detection of invasive marine fishes.

• Ecological modelers use NAS data in predictive modeling to 

show possible distributions of species in future invasions.

• South Carolina State planners used pathway analysis to determine 

where to direct their public education as an intervention for 

decreasing new invasions.

Management and Planning 

• Occurrence data supports national assessments of aquatic 

invasions and regional management of non-native aquatic species.

• Reports from NAS have been used to document the range 

expansion of invasive species throughout a region of concern.

Federal Policymaking 

• Data and reports from NAS have been used to make decisions 

about Lacey Act listings.

• NAS provides information for Congressional testimonies.
NAS Specimen Records 

Each specimen record documents a non-native aquatic 

species in a particular location at a point in time. The specimen may not have survived or reproduced after the sighting, 

however, the record provides documentation of the event, 

allowing researchers to analyze trends and pathways in 

introductions. All specimen records include the location, 

date, and identity of the non-native aquatic species. Other 

details, such as photos or museum specimens (in cases 

where the organism was caught), are available for some 

records. To the extent possible, the database includes the 

best available information on the population status of each 

species, documenting whether it has failed or established a 

self-sustaining wild population. The database also distinguishes between non-native species that are transplants, 

meaning they are native to a different part of the U.S., and 

exotics which originate from other countries.

Records are compiled from published materials, such 

as books, journal articles, and technical reports, as well as 

records and reports from federal and state fish and wildlife 

agencies, museum holdings, and university researchers. 

Fishermen, boaters, and divers, and other members of the 

general public also submit reports of sightings. 

To ensure the integrity of the data, the identity and 

reported location of each species is verified by NAS program staff before each new specimen record is entered into 

the database. Supporting documentation, such as collection 

information, photos, supporting academic literature, or a 

first-hand account, is attached to the specimen record.

This specimen record provides details about a single introduction 

of the vermiculated sailfin catfish, including a map of the location.

Queries and Searches

Users can select text-based search to type in a genus, 

species or common name, or browse all occurrences within a 

broader taxonomic group, such as frogs, mammals, or fishes. 

Specimen records can also be queried according to geographic 

criteria, including:

• State 

• County

• Major drainage area—2-digit Hydrologic Unit Code (HUC)

• Drainage—6-digit HUC

• Watershed—8-digit HUC

• Using advanced text searches, users can filter results 

by additional criteria, such as year, freshwater or marine 

environments, introduction pathway, and exotic or 

transplant categories. 

A text-based search for “carp” as a common name returned 

these 13 carp species. From here, users can access a point 

map showing locations of sightings.
Assessing Trends in Introductions 

The NAS database also includes summary graphs to 

show key facts and trends, such as origins of non-native 

aquatic species, as well as pathways and environments 

where they have been introduced. The graphs can include 

all species in the U.S. or by individual state. They also 

can be displayed by taxonomic groups (fishes, mollusks, 

crustaceans, reptiles, and amphibians). 

Types of graphs currently available include:

• Introductions over time

• Introductions by taxonomic group

• Native transplants versus foreign (exotics)

• Introductions by pathway

• Continent of origin of exotic species 

This bar graph compares transplants with exotics, 

including the categories of hybrids, cryptogenic, or 

unknown origins.

Pie charts, such as this one for Florida, 

catagorized non-native aquatic occurrences 

by their introduction pathways.

Interpreting Point Maps 

Each individual specimen record includes an 

online map displaying the location of the occurrence to the finest scale possible. Point maps show 

all records for a given species. Some records 

(particularly early dates) have imprecise locations, 

therefore NAS uses a point distribution system to 

enable all records to be georeferenced by latitude 

and longitude (lat-long). Each record’s lat-long 

accuracy is designated by one of three categories, 

which are indicated by shape on the map: 

○ Accurate – Lat-long is reasonably 

close to described location, such as 

“mouth of Smith Creek.”

□ Approximate – Lat-long is in the 

general vicinity of the collection, 

such as “a pond in Gainesville, Florida.” 

 Centroid – Lat-long is calculated based 

on the center of a polygon, such as with 

county- or drainage-level records. This point map shows the results of a query for 

bighead carp. Colors indicate population status. 
Watch for New Introductions! 

The NAS Alert System is designed to notify registered users of new 

occurrences based on geographic area, species, or broad taxonomic categories. 

•	 State Watches track sightings by State. 

•	 Group Watches include categories of fish, amphibians, 

reptiles, mollusk, crustaceans, and other species. 

•	 Species Watches create single-species alerts.

To register to receive alerts, visit the NAS homepage at http://nas.er.usgs.gov. 

Alerts are triggered for any recent occurrence not previously been reported in 

a given country, state, county, drainage system, or bioregion. 

Report Sightings! 

The public plays a significant role in the invasive species issue by acting 

as “early detectors” of new invasions. Users can locate the waters where a 

non-native species was seen, accurately report the geographic coordinates 

using an online map, and upload a photo for NAS program staff to verify the 

species identity. This online tool has been a very effective for reporting new 

invasions. A recent analysis of the NAS Alert System showed that approximately two-thirds of the alerts generated in the past 5 years have come 

from personal communication through this volunteer reporting mechanism. 

Reports can be submitted online at: 

http://nas.er.usgs.gov/SightingReport.aspx.

Partnerships 

The NAS program works closely with state agencies and develops special 

tools with partnerships, such as integrated reporting and filtered website views. 

Working with the Smithsonian Environmental Research Center (SERC), NAS 

has helped to create an integrated data system called NISbase (www.NISbase.

org) that links SERC invasive marine species data with NAS invasive freshwater species data. Through other partnerships, NAS offers custom, regional views 

of the database that allow managers to focus on a specific area of interest. Two 

examples of this include the National Oceanic and Atmospheric Administration (NOAA) Great Lakes Aquatic Nonindigenous Species Information System 

(GLANSIS) and a regional view of the Columbia River that NAS provides as 

part of a consortium of state, federal and nongovernmental partners. NAS is 

also a member of the Global Invasive Species Information Network (GISIN) 

and Global Biodiversity Information Facility (GBIF), and provides data to these 

larger networks as well as other invasive species databases. Data analysis, time 

series maps, and detailed regional maps can be designed for special projects. 

For More Information 

Pam Fuller, Biologist/NAS Program Leader

USGS Southeast Ecological Science Center

7920 NW 71st Street 

Gainesville, FL 32653

Phone: 352-264-3481

Email: pfuller@usgs.gov

Potential partners can contact NAS for more information 

about custom maps and other tools.

Visit NAS online at: http://nas.er.usgs.gov 

Suggested Citation:

Pawlitz, R.J., and David, K.D., 2012, The National Nonindigenous Aquatic 

Species Program: U.S. Geological Survey Fact Sheet 2012-3100, 4 p.