First-year movement and survival of stocked Striped Bass in a coastal system inferred from individually marked fish

Abstract Objective Stock enhancement programs support many fisheries worldwide, including those for Striped Bass Morone saxatilis. Understanding survival and movement after stocking can help to inform stocking strategies. The goal of this research was to evaluate stocking success by tracking movement and survival of phase II Striped Bass (200–250 mm total length) in the Great Pee Dee River system of coastal South Carolina. The objectives of this study were to (1) determine daily movement across river basins and identify areas where Striped Bass congregate during their first year to infer potential nursery habitat; and (2) estimate first-year survival poststocking. Methods Hydroacoustic transmitters were surgically implanted into 28 phase II Striped Bass prior to stocking on December 1, 2020. Fish were monitored on 74 fixed receivers that were distributed throughout the Great Pee Dee River system. Daily survival and movement were estimated using a multi-state Cormack–Jolly–Seber model. We evaluated multiple models to describe survival (e.g., constant, daily random effect model, and varying by season) and capture probability (e.g., constant and varying by zone). Result Daily persistence probability was high for all zones, and most fish spent most of their time in the delta region at the confluence of the Great Pee Dee and Waccamaw rivers. Median daily survival was greater than 0.986 across all days, and cumulative survival after the 323-day period of the study was 0.131. Survival was highest in winter and lowest in summer. Conclusions This study provides insights into the fate of stocked phase II Striped Bass in their first year poststocking. We identified potential nursery habitat that could be critical for successful long-term viability of this population. We suggest that stocking locations be moved closer to the nursery habitats in the delta region of the Great Pee Dee River–Waccamaw River confluence and closer to Winyah Bay.