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| NAS - Nonindigenous Aquatic Species |
This map layer is a compilation of confirmed quagga mussel sighting
reports in the United States and Canada from 1988 through 2009 and is updated
daily. It provides geographical and historical information to show distribution
over space and time. Each sighting report does not necessarily represent an established
population, but for most locations it does. The reports came from a variety of
Federal, State, and municipal agencies, universities, public utilities, engineering
and private consultant firms. The locations of confirmed sightings were registered
at 1:100,000-scale on EPA Reach File Version 3.0 and are maintained as an ArcInfo
shapefile. These data are intended for geographic display and analysis at the
national level, and for large regional areas. Sightings were reported with varying
levels of accuracy. Some of the reports were as latitude-longitude coordinates,
some as river miles, and others as just a lake, beach, harbor, or a water body
and nearest town name. If no specific location was reported in a lake, the point
was assigned in the center. The data should be displayed and analyzed at scales
appropriate for 1:2,000,000-scale data. It is possible that quagga mussels can
be found at other locations not displayed here, but have gone unreported to this
effort. It is also possible that zebra mussels may not persist at a particular
site after the introduction through natural means or eradication. No responsibility
is assumed by the U.S. Geological Survey in the use of these data. Acknowledgment
of the U.S. Geological Survey would be appreciated in products derived from these
data. Also see the Zebra
Mussel Distribution
Quagga mussel locations are represented with larger red markers.
Click on a marker for more information.
Suggested citation: Benson, A. J. 2010. Quagga mussel sightings distribution. Retrieved [add current date] from http://nas.er.usgs.gov/taxgroup/mollusks/zebramussel/quaggamusseldistribution.asp.
For more information, contact: Amy Benson, abenson@usgs.gov