Freshwater Fisheries
Title:	Development of a fish assemblage assessment index for non-wadeable large rivers in maine and new england: 2002-2008
Author(s):	Chris O. Yoder, Midwest Biodiversity Institute; Brandon Kulik, Bryan Apell, Kleinschmidt Assoc.; David Haliwell, Maine DEP
Date:	Tuesday, April 27, 2010
Time:	10:20 am - 10:40 am
Room:	Salon C
Abstract: We conducted systematic sampling of the fish assemblages of the non-wadeable rivers of Maine during 2002-8. The initial purpose of this project was the development of a multimetric index that is framed within the Biological Condition Gradient. Estimates of relative abundance for species that are amenable to efficient capture has been determined on an annual basis at a large number of sites located along extended river reaches. In 2008 we essentially completed the statewide coverage needed to support index development and testing. Exploratory analyses revealed strong differences in key assemblage parameters and species relative abundances between major habitat types (riverine, impounded, tidal), along each river (upper to lower reaches), and along a latitudinal gradient. The mapping of species relative abundance data on a statewide basis served to enhance our understanding of environmental requirements and tolerances based on patterns in spatial distribution. We then developed more detail about the ecological roles of each species in accordance with previously used and our own unique assemblage guilds. These types of analyses were prerequisite to the primary goal of developing multimetric indices, which are also contingent on the accurate description of regional reference conditions. Direct reference analogs are either rare or not entirely representative of the historical potential for these large rivers, thus historical knowledge of the fish assemblage is also needed. The Biological Condition Gradient tool proved useful for visualizing reference condition and understanding how Maine river fish assemblages respond to incremental stressors over time and space. An intial Index of Biotic Integrity was developed and initially tested in 2007 and provides the baseline for extending it to other New England rivers.
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