Importance of the Connectivity of Backwater Areas for Fish Production in Demopolis Reservoir, Alabama

Abstract

ABSTRACT Larval and juvenile fishes were sampled in backwater areas and the river proper in Demopolis Reservoir, Alabama, in 2002 and 2003. Because backwater habitats have declined in Demopolis Reservoir due to sedimentation, we sampled both closed-access and open-access backwaters to assess the effects of the loss of connectivity on the use of these areas for spawning and juvenile habitats. Larval fishes were generally more abundant in the disconnected backwater habitats, least abundant in the riverine habitat, and intermediate in the open-access backwaters in both years. Juvenile fishes were only sampled during 2003. Abundances of juvenile largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus) were higher in backwater areas than in the river proper. Three species of nongame fish were collected in greater numbers in the river proper, whereas four species were collected in greater numbers in backwater habitats. Twenty-three species were collected from open-access backwaters, but only 18 of these were also collected in backwater areas that had been closed off. Based on our results, Demopolis Reservoir fits the prevailing paradigm that backwater areas provide essential habitat for spawning and the production of early life stages of fish.