Assessing the outcomes of stocking of hatchery juveniles in the presence of wild Atlantic salmon
University of New Brunswick
Stocking of hatchery-reared, juvenile Atlantic Salmon (Salmo salar) is a common enhancement and recovery strategy across jurisdictions, yet its impact remains uncertain. We investigated the potential effectiveness of stocking in the Miramichi River system where approximately 150,000 first-feeding fry are stocked annually in reaches where wild juveniles are present. Local site and landscape level characteristics were used to fit predictive models for wild parr densities measured as Percent Habitat Saturation (PHS) using Partial Least Squares Regression (PLSR). The observed PHS of stocked sites was found to be significantly lower than predicted, suggesting stocking has not been effective in increasing the PHS in the studied stocked sites. The results suggest that habitat and other density dependent effects likely limit productive capacity in this system, and consequently, may limit the effectiveness of stocking in other systems with natural production.