The Influence of River Connectivity on the Fish Community and Sport Fish Abundance in Demopolis Reservoir, Alabama

Demopolis Reservoir is a short-retention (three-day) mainstream impoundment where sedimentation over the past 50 years has caused separation of some backwater areas and sloughs that were historically connected to the reservoir during normal water level periods. We collected fish with direct-current electrofishing from closed-access backwater (separated from the reservoir unless flood events occur), open-access backwater, and mainstream riverine habitats four times a year over a year and a half to document species richness, diversity, evenness, and relative abundance of all fish and major sport fish. Species richness, represented by more than one individual, was the lowest in closed-access backwater habitats and highest in the open-access habitats. Fish communities were similar, but closed access habitats were more dissimilar from riverine habitats. Species diversity and evenness were highest in riverine habitats, as gizzard shad (Dorosoma cepadianum) and centrarchid sport fish that included largemouth bass (Micropterus salmoides), crappie (Pomoxis spp.), bluegill (Lepomis macrochirus), and redear sunfish (L. microlophus), were more abundant in closed- and open-access backwater habitats than in riverine habitats. Re-establishing connectivity to closed-access backwaters to riverine portions of the reservoir will not only provide anglers access to fishery resources, but permit exchange of diverse fish faunas. Key words: connectivity, sedimentation, fish community, similarity, diversity, sport fish

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