Effects of Simulated Removal of Striped Bass from a Southeastern Reservoir

Abstract

Since the introduction of striped bass Morone saxatilis and hybrids of striped bass and white bass Morone chrysops into reservoirs, much concern has been directed at the possibility of these predators competing with other sport fishes for limited prey. If density of striped bass is reduced or eliminated through modifications of the stocking program, the prey not consumed by striped bass may be shifted to other sport fishes. The resulting increase in biomass of other sport fishes would be a function of the amount of added prey, the percent of this additional prey eaten by other sport fishes, and the efficiency with which the prey is converted into biomass. We used bioenergetics models to estimate annual striped bass prey consumption in Norris Reservoir, Tennessee. Total annual consumption was estimated at 52 kg/ha (estimated range = 17–100 kg/ha), clupeids accounting for the majority (94%), followed by lepomids (4%) and other food items (2%). Existing biomass of black basses Micropterus spp., crappies Pomoxis spp., and percids Stizostedion spp. was about 65 kg/ha (estimated range = 35 − 106 kg/ha). Given the complete removal of striped bass, modeling indicated that the most probable increase in the biomass of these sport fishes would be about 3% with a 75% probability that it would be less than 12%. Thus, not even the complete removal of striped bass would measurably increase the biomass of other sport fishes.