Distribution and Movement of Creek Chubs (Semotilus atromaculatus) in Agricultural Headwater Ditches of the Cedar Creek Watershed

摘要

Over 70% of the land in Indiana is dedicated to agriculture. Drainage ditches are used to take excess water from farms and place it into creeks and streams. This water is contaminated with agrichemicals and sediments, and the in-stream habitat and hydrology are negatively impacted. Poor in-stream habitat limits the species that live there. Creek chubs (Semotilus atromaculatus) are a tolerant species that are commonly found in these ditches at greater abundance than in the creeks that they feed. The relative abundance of chubs was compared among sites in Cedar Creek and agricultural ditches near Waterloo, IN from 2006-2013. In 2013, all five ditches sampled had a higher relative abundance of chubs than that in Cedar Creek. Particularly, sites in the A and C ditches had a relative abundance of 0.1629 and 0.4283, while that in Cedar Creek was 0.0865. The objective of this project was to determine if creek chubs prefer ditches over Cedar Creek. Chubs may prefer ditches to avoid predators, to access better food resources, and to reduce competition. We hypothesized that given a “choice” creek chubs would choose the ditches over the creek, even though creeks have much better habitat. Mark and recapture techniques were used to determine the movements of creek chubs in a research study area that has been active for nearly 10 years. We used electrofishing techniques to capture creek chubs during October and November, 2014 from 125-130 m zones in two ditches (A and C). Fish were tagged and coded by date and initial location of capture using Visible Implant Elastomer techniques. Chubs from both ditches were released at the same location, 300 m upstream of the mouth of ditch A, and 160 m downstream of the mouth of C ditch. One week after release, the creek and ditches were sampled again in an attempt to recapture tagged fish. A total of 17% of chubs collected from ditches were recaptured. However, most of the chubs (50%) were recaptured within 50 m of the release point. Another 33% were recaptured in Cedar Creek beyond 50 m from the release point. The remaining 17% were recaptured in A and C ditches. If release and recapture data represent the natural tendency of chub movement, then it appears that they do not have a strong preference for ditches. Recapture efforts will resume in spring, 2015 to determine if the distribution of chubs has changed since November. The results of this project will contribute to a better understanding of the distribution of forage fish in agricultural headwater streams.