Effort Needed to Estimate Species Richness in Small Streams on the Great Plains in Wyoming

Abstract

Our objective was to define the sampling effort needed with electrofishing gear or seines to capture all of the fish species present in sampling reaches on small streams of the Great Plains. The study was conducted because of recent interest in assessing the status of fishes in small streams of the Great Plains, which have lacked information that would enable sampling protocols to be developed. Based on the wetted widths (2–11 m) of sampling reaches, we defined the sampling effort needed to capture 90% and 100% of the fish species present. For electrofishing gear, sampling three 50-m-long units of the stream assured capture of 90% of the fish species present, and sampling four 50-m-units assured capture of 100%. When seines were used, sampling of four 50-m-long units captured 90% of the fish species present, and six 50-m-long units assured capture of 100%. As wetted width increased, the length of stream that needed to be sampled remained relatively constant; accordingly, the surface area of stream that needed to be sampled increased. This was true for both electrofishing gear and seines. The necessary sampling effort was less than that indicated for streams in the southeastern and midwestern United States. Our results can be useful to managers and researchers designing surveys of fishes in small streams on the Great Plains.