Influences of water velocity and hydropower operations on spawning site choice and recruitment success of Lake Sturgeon (Acipenser fulvescens) in the Winnipeg River, Manitoba

Although once found in large numbers throughout North America, lake sturgeon (Acipenser fulvescens) populations have declined over the last 100 years, and the species is currently listed as threatened or endangered throughout much of its native range. Although spawning success is vital to lake sturgeon survival, little is known about the effects of water velocity patterns and fluctuations on spawning site choice and larval yield. Research pertaining to this area was carried out on the Winnipeg River, MB, within a 23 km stretch between Seven Sisters Generating Station and Lac du Bonnet. The objective of this study was to determine how lake sturgeon spawning site choice is affected by generating station flow rates and to determine (qualitatively) if flow conditions during incubation impacts natural hatching success. This was done by acoustically tagging and tracking spawning fish, and capturing drifting larvae. Controlled studies were carried out to quantitatively evaluate the impact of flow strength on hatching success. The results of this study will pave the way for future studies aimed at identifying key habitat variables for lake sturgeon spawning, survival, and growth, and may aid in future habitat remediation strategies.