DISTRIBUTION AND ABUNDANCE OF NON-INDIGENOUS FISHES IN THE GREAT RIVERS OF THE 
CENTRAL BASIN, USA 

Mark S. Pearson1, Dave Bolgrien1, Ted Angradi1, Frank H. McCormick2, Terri 
Jicha1, Debra L. Taylor1, Brian H. Hill1

1USEPA, ORD, NHEERL, Mid-Continent Ecology Division, Duluth, MN 55804

2USFS, Environmental Sciences Research, Olympia, Forestry Sciences Laboratory, 
Olympia, WA 98512

      EPA has implemented the Environmental Assessment and Monitoring Program, 
Great Rivers Ecosystems (EMAP-GRE) to assess the ecological condition of the 
Upper Mississippi, Ohio and Missouri Rivers using a probabilistic sampling 
design. Fish assemblages, other biotic assemblages, and water quality parameters 
will be used to assess the condition of these rivers. One important biotic 
indicator is the relative abundance and distribution of non-indigenous fishes 
because they are a biological stressor that may disrupt the function and 
structure of aquatic ecosystems. Fish assemblages were sampled in 2004-2005 on 
all three rivers using daytime electrofishing along two continuous 500 m 
shoreline transects (primary and secondary) at each site. The most abundant non-
indigenous species across all three rivers was the Common carp (Cyprinis 
carpio). The Bighead carp (Hypophtlamichthys nobilis) and Silver carp 
(Ctenopharyngodon idella) were collected in each river, although in smaller 
numbers.  Data will be presented that show the occurrence and proportion of 
river length occupied by non-indigenous fishes in the Great Rivers of the 
central basin, USA. This abstract does not necessarily reflect EPA policy.
      
Keywords:  Great Rivers, fish assemblages, non-indigenous fish