Fish use of artificial dyke structures in the Kanawha River, West Virginia

Artificial structures have been used in the past to potentially increase fish production by providing cover, feeding grounds and spawning areas. In some areas the US Army Corp of Engineers has constructed dykes to provide additional habitat for river fishes and to mitigate against navigable related impacts. This study is designed to test whether such structures really function as viable habitats as evidenced by increased abundances relative to natural reference areas lacking structures. Five sets of structures in the Kanawha River, West Virginia were sampled via boat electrofishing using point-abundance sampling twice monthly from June through October 2002 and 2003. We found a difference in taxa using structures relative to reference area. Cyprinidae (p = 0.5 to 0.1) and Catostomidae (p = 0.1) abundance was not dependent on artificial structure in comparison to natural reference. Artificial structures use was most important among Centrarchidae species, especially juveniles, including black bass and several species of Lepomis (p < 0.001). Further, distribution offish between areas with and without structures appears most affected by short-term river flow in 2003 (p = 0.0008) where artificial structure serve as flow shelters (p = 0.0008) and in 2002 water temperature (p = 0.0007). These patterns suggest structures are viable mitigation measures that target and benefit fish of economic interest.