
National Water Quality Assessment Program (NAWQA)
Tennessee River Basin Study
Photo Gallery
The
types and numbers of fish species present in a stream can be used as an
indicator of both the past and present condition of the watershed. Because most species require clean
substrate to spawn and clear water to feed, their condition and presence can be
used to develop biological indices that serve as a “health” rating for a
stream, to evaluate a particular land-use type, or monitor water quality
impacts below a point-source discharge. Various techniques are utilized to
collect fish such as, hauling a seine through pools and backwater areas to
actively pursuing fish with a towed electrofishing unit.



Last Modified 7/3/01
maintainer rmitchel@usgs.gov