Growth and Mortality of Hatchery‐Reared Striped Bass Stocked into Nonnatal Systems

Abstract

Cross‐stocking involves the use of fish from nonnatal sources to augment populations. This practice may not be effective, especially if fish from different populations are not well adapted to the environmental conditions of the areas intended for enhancement. Yet, the ecological consequences of cross‐stocking have received little attention, particularly in coastal environments. We used tag return data (1990–2010) from an ongoing stock enhancement program to compare the growth and mortality of hatchery‐reared Striped Bass Morone saxatilis of Roanoke River origin between their natal (Albemarle Sound estuary) and two nonnatal systems (Tar‐Pamlico and Neuse rivers) in North Carolina. Despite their Roanoke River origin, stocked juveniles exhibited high fidelity (>90%) to nonnatal systems and similarly high growth as in their natal habitat (von Bertalanffy K values were statistically similar among systems and ranged from 0.54 to 0.61). However, time‐at‐liberty estimators of total mortality (Z) indicated stocked Striped Bass experienced significantly higher mortality in nonnatal (Z values, 0.48–0.51) versus natal (Z = 0.33) systems. Therefore, while cross‐stocking may not contribute to stock rebuilding, it appeared to be an effective management tool for supporting local put‐and‐take fisheries for this recreationally and commercially important species. Received March 11, 2014; accepted July 16, 2014

Juvenile and Adult Striped Bass Mortality and Distribution in an Unrecovered Coastal Population

“…In contrast, Callihan et al. () used a time‐at‐liberty approach to estimate discrete total mortality of Neuse River Striped Bass from the time of stocking to the time of capture (mean = 2.1 years), resulting in a lower estimate of 48%.…”

“…Tagging studies conducted by Hawkins (), NCDMF and NCWRC (), and Callihan et al. () indicated that Neuse River Striped Bass are riverine, and therefore any differences between true survival and apparent survival should be negligible. Another limitation of both models is that adults were assumed to experience equal mortality across all sizes; however, harvest mortality would not be equal.…”

“…Although it is possible that some adult Striped Bass emigrated permanently, emigration out of the Neuse River is rare (Hawkins ; NCDMF and NCWRC ; Callihan et al. ).…”