|Shields Jr, Fletcher|
Submitted to: Journal of Environmental Science and Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 28, 2011
Publication Date: August 20, 2012
Citation: Knight, S.S., Cullum, R.F., Shields Jr, F.D., Smiley, P.C. 2012. Effects of channelization on fish biomass in river ecosystems. Journal of Environmental Science and Engineering. 1(8):980-985. Interpretive Summary: Straightening of a river channel can cause bank erosion that results in wide, shallow river with very little aquatic habitat. Fish were sampled using electroshocking gear and hoop nets to evaluate the impact of stream bank erosion and loss of habitat resulting from channelization on fish communities. This research shows what when a river is channelized the loss of habitat results in a river that can only support very small fishes. This information may be useful in making comparison of damaged riverine ecosystems and assist managers in determining impairment and success in meeting Total Maximum Daily Load (TMDL)goals.
Technical Abstract: Channel straightening of a meandering river is a common trigger of channel incision which may results in stream bank destabilization. Several of the rivers in the upland portion of the Yazoo River Basin have subjected channelization resulting in changes in the physical and geomorphological characteristics of these systems. Fish were sampled using electroshocking gear and hoop nets to evaluate the impact of stream bank destabilization and loss of habitat heterogeneity resulting from channelization on fish communities. While distinct differences in the fish communities were evident, only the Skuna appeared to have characteristics of a damaged system. More than 95% of the catch was comprised of species reaching an adult length of less than 300 mm. The lotic omnivorous fishes that dominated the catch from Skuna are often associated with smaller streams rather than rivers. Furthermore, 72% of the catch consisted of fish preferring littoral zone habitats. The shallow depth and lack of woody debris in Skuna provided a selective advantage for smaller species of fish that could use shoreline habitats as protection from the current. Based on results from the Skuna River, channel straightening that leads to channel incision, bank failure and over widening provide habitats too shallow to support a community of fishes typical of northern Mississippi riverine system. This information may be useful in making comparison of damaged riverine ecosystems and assist managers in determining impairment and success in the Total Maximum Daily Load (TMDL) process.