The main goal of the Clean Water Act is to restore and maintain the physical, chemical and biological integrity of our nation's water, says Bailey, an aquatic biologist in the agency's Water Quality Division. It makes sense to monitor the biology itself. Bailey is working with Jack Emblom, biologist with the Minnesota Department of Natural Resources, to assess water quality in the Minnesota River watershed by evaluating the characteristics of the fish communities at several sites. There are several reasons fish work well as biological indicators, Bailey says. They are highly visible to the public, they tend to remain in the same area during the summer, have a long life span and, for many species, their tolerance to environmental stress is well known.
Fish also incorporate the history of the river.
The effects of a spill or midnight dumping may not be present for long in moving water, but can sometimes be measured in the river's fish. Biological monitoring has been used to uncover problems in a stream that researchers didn't suspect were present. Bailey and Emblom are using the Index of Biotic Integrity to evaluate fish communities in the Minnesota River watershed. The index is based on 12 characteristics of fish communities. It includes information about the numbers of native, darter, sunfish and suckers species.