M. J. Cytreski and J. J. Ney, Department of Fisheries and Wildlife, Virginia Polytechnic Institute and State University, 100 Cheatham Hall, Blacksburg, VA 24060-0321

Abstract. In Smith Mountain Lake, Virginia, the two most popular and abundant game fishes, the indigenous largemouth bass Micropterus salmoides and the non-native striped bass Morone saxatilis, rely heavily upon introduced alewife Alosa pseudoharengus and gizzard shad Dorsoma cepedianum as forage. Motivated by angler desire to increase striped bass stocking levels, this ongoing study was undertaken to determine the annual demand of predators for clupeids and the yearly production of these critical prey species. The demand problem is being handled using bioenergetics modeling. The two primary inputs for deriving individual consumption are diet composition of predators by percent weight and predator growth rates. Extrapolation to population consumption requires abundance estimates for both predator species. Data requirements have been satisfied using a variety of sampling methods, including electrofishing, gillnetting, and rotenone surveys. It was found that largemouth bass annually consume 3.6 kilograms/ha of alewife and 5.2 kilograms/ha of shad, while striped bass utilize 33.1 and 15.2 kilograms/ha, respectively. Over 80 percent of largemouth population consumption is attributed to fish age four and younger. For striped bass, these cohorts are responsible for over 90 percent of population consumption. Average annual conversion efficiencies for largemouth bass range from 8 to 41 percent, and 6 to 23 percent for striped bass.