Fish Assemblage Monitoring

Fish assemblages include species that represent a variety of trophic levels (omnivores, herbivores, insectivores, planktivores, piscivores), and that exhibit a range of tolerance to water quality or habitat degradation. Fish are long-lived and integrate short-term temporal environmental changes, and also integrate effects of lower trophic levels (e.g., primary producers and benthic macroinvertebrates); thus, fish assemblage structure is reflective of integrated environmental health. (See EPA's Introduction to Freshwater Fishes as Biological Indicators). Of all biological components of waters fish probably receive the greatest public attention because of sport and commercial fishing and attendant concerns regarding fish production success and safety for human consumption.

Fish assemblage monitoring was conducted using a Smith-Root L-24 Electrofisher and an 8 foot seine. Using two identical sets of electroshocking equipment both banks were shocked simultaneously. This required one team member operating the electroshocking equipment and another to net and collect fish on each stream bank. For wide streams two teams conducted sampling, working both banks as well as the center of the stream. After electroshocking the stream, four seine passes were taken to capture a representative sample of fish that might not have been captured using electrofishing techniques. Both the electroshocking and seine samples were composited into one sample. All fish that could be identified on-site after electrofishing were identified and released. Fish that could not be readily identified (with a high confidence of certainty) were preserved in 10% formalin, labeled and brought back to the lab for taxonomic identification. Taxonomic references used to identify the samples included Fishes of Kansas (Cross, 1967; Cross, 1995) and The Fishes of Missouri (Pflieger, 1975).