Fragmented Coves in an Aging Reservoir: Do They Serve As Nursery Habitats for Fish Assemblages?

Lake Texoma is home to several isolated coves walled off by sedimentation as a result of reservoir aging. The reservoir fragments are relatively new features on the landscape, isolated from the reservoir and taking diverse forms. These fragments have been formed on the arms of two physicochemically distinct rivers entering Lake Texoma (Red and Washita). Fragmented coves are located within the river-reservoir interface, a highly productive and ecologically important transitional zone. We examined the structure of young-of-the-year (YOY) fish assemblages utilizing these habitats and investigated the influence of environmental factors on taxonomic and guild composition.  Sampling was carried out in two phases from March through November 2014. The first phase (March-July) utilized light traps and push nets to target larval specimens. The second phase (August-November) utilized fyke nets to target juveniles. Differences in YOY fish abundance were observed between river arms and individual fragments. Some of this variation was related to physiochemical and morphological differences between fragments. While habitat generalists were dominant throughout our study area, some fragments hosted species that rely upon river floodplain habitats for reproduction. This work should provide managers with insights into the role that these novel habitats play in supplementing reservoir fish assemblages.