Fish Collections in Wilson Creek
March 19, 2005
Thomas More College

The data from the fish collections in Wilson Creek (Table 1) reflect a high-quality habitat with clean water. For instance, indicator species of good water quality, such as darters and sculpins, were present at all fish sites surveyed along the mainstem. These species were absent in the lentic backwater areas occupied by the former channel. The presence of these species reflects optimal chemical and physical characteristics and high quality riffle areas within the study areas. Darters and sculpins cannot tolerate heavy siltation and low dissolved oxygen levels typically associated with degraded streams. Furthermore, a variety of substrates within the stream was observed including sand, cobble and gravel. Larger rocks and trees were also present which provide refuge, habitat and stability and also prevent erosion.

In addition to the variation in substrate, similar variation in flow regimes and water depth were seen which is helpful in creating a natural series of pools, riffles and runs associated with a stream of this size. Although some pollution-tolerant species were present, namely creek chub (Semotilus atromaculatus), and bluntnose minnow (Pimephales notatus), neither dominated the samples and though no quantity date were collected, all species collected were well-represented.

Furthermore the percent of omnivores was low and the percentage of insectivores was at a moderate level which indicates a stable environment. The presence of simple lithophils also indicate the presence of high quality habitat, specifically clean gravel and cobble substrates and the low level of siltation in this stream. Finally, the proportion of individuals with DELTS (deformities, eroded fins, lesions and tumors) was very low. Only a few fish with DELTS were noted and these were found in the old channel not connected to the new one.

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