Abstract

During the first year of life of Striped Bass Morone saxatilis, the effect of estuarine habitat use on growth rate is poorly understood. In a split-plot experiment, growth and feeding rates were compared between anadromous (Chesapeake Bay) and nonanadromous (Santee-Cooper) broods of juvenile striped bass (45–90 days posthatch) exposed to a range of salinity levels (0.5, 7, and 15 ppt) and temperatures (20, 24, and 28 C). At 28 C, which best simulated the summertime conditions of young juveniles, Chesapeake Bay fish showed highest growth performance. For this temperature and strain, growth was approximately 40% higher at 7 ppt than at 0.5 or 15 ppt. Santee-Cooper juveniles showed no response to salinity. Over combined temperature and salinity levels, Chesapeake Bay juveniles experienced 22% higher growth rates than did Santee-Cooper juveniles, supporting a proposal that early growth rates are inversely related to latitude. Because salinity had a strong effect on Chesapeake Bay striped bass growth rate, we also conclude that variation in distribution patterns within and among estuaries can substantially modify the expected latitudinal gradient in growth rate.