Variation in lake sturgeon (Acipenser fulvescens Rafinesque, 1817) abundance in rivers across Ontario, Canada

Abstract

Summary The objectives of this study were to (i) assess the variation in relative abundance of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) subjected to various man-induced stresses and physical characteristics at a landscape scale across Ontario; and (ii) ascertain the factors that explain the variability observed among rivers using a multivariate approach. A standardized index netting program targeting juvenile and adult Lake Sturgeon was conducted over two field seasons at 22 river sites across Ontario. Each river had unique or different human-induced stresses and physical characteristics. Relative abundance of Lake Sturgeon varied in river across the Ontario landscape. A principal component analysis was conducted using site physical characteristics with the associated anthropogenic stressors. The catch-per-unit-effort (CPUE) for juvenile and adult Lake Sturgeon were then regressed with the scores of principal components having eigenvalues >1. The variation observed was best explained by the negative relationship observed between CPUE and the presence of hydroelectric generating stations. Historical commercial fisheries also had an effect on Lake Sturgeon abundance whereas subsistence fisheries seemed to focus on rivers that were not regulated and where Lake Sturgeon numbers were greater. Research and recovery efforts should focus on minimizing the impact of hydroelectric generation on Lake Sturgeon while achieving socioeconomic goals.