Ecology, behavior, and biological characteristics of juvenile lake sturgeon, Acipenser fulvescens, within an impounded reach of the Winnipeg River, Manitoba, Canada

Abstract

The lake sturgeon, Acipenser fulvescens, was once abundant throughout Canada and the United States, however, high commercial harvests and habitat alterations have dramatically reduced most populations. The species was extirpated from many rivers that it once inhabited, and has been designated as threatened or endangered throughout its range. Currently, few healthy lake sturgeon populations remain and the species is receiving considerable attention with respect to its protection and recovery. Although considerable effort is underway to conserve the species, several factors, including over-harvest and habitat alteration, pollution and a general lack of understanding about lake sturgeon ecology and behavior continue to hamper recovery efforts. This thesis examined the ecology and behavior of juvenile lake sturgeon within a 41 km long impounded section of the Winnipeg River, a large river in the Canadian Shield, over a three-year period (2006 – 2008). Habitat preferences, species associations, diet, and movement were described on a seasonal basis. Biological characteristics were also described for juvenile lake sturgeon within the study area. Studies presented in this thesis are among the first conducted for juveniles of this species in the Hudson Bay drainage basin, and from large riverine environments in general. Results are important, not only for improving our understanding of lake sturgeon at the juvenile life history stage, but for facilitating further research. In particular, future research studies identified in the final chapter have the potential to enhance our understanding of factors influencing mortality during the early life history stages of the lake sturgeon, and therefore, greatly enhance recovery efforts.