Over-Wintering Physiology of Age-0 Lake Sturgeon: Implications for Conservation Aquaculture

Lake Sturgeon Acipenser fulvescens were recently recommended by the Committee on the Status of Endangered Wildlife in Canada for listing as endangered under the Species At Risk Act in the province of Manitoba, Canada. To remediate the situation, conservation aquaculture is currently used as a management tool to enhance Lake Sturgeon populations that are at risk or endangered. One of the most limiting components of the conservation effort is our understanding of energy requirements that allow age-0 Lake Sturgeon to survive their first winter. In this study, age-0 fish (mean weight 5.6 g ± 0.5 S.E.; mean total length 12.7 cm ± 0.4 S.E.) were held in groups of 12 individuals (for a total of 10 groups) and starved for a period of four weeks while being held at 1 ± 1°C. This setting was intended to mirror winter conditions that occur in the Winnipeg River. While mortality was high (42%) during the experiment, results indicated that fish with a water content < 90% and energy density > 2000 J/g were more likely to survive. Understanding this threshold will help in future refinements of rearing conditions, which look to improve the survival of age-0 fish once released into the wild.