Lake Sturgeon Geographic Range, Distribution, and Migration Patterns in the Saskatchewan River

We examined geographic range, distribution, and migration patterns of Lake Sturgeon Acipenser fulvescens within the largest contiguous section of the Saskatchewan River system in Saskatchewan, Canada. Lake Sturgeon use portions of the North, South, and main‐stem Saskatchewan River during the summer months. The Forks area was observed to be an overwintering area. Lake Sturgeon were observed to migrate each year, and all Lake Sturgeon migrated at least once in the 3‐year study. Lake Sturgeon were observed to undertake significant migrations (>100 km/year) using all three rivers. Migration initiation date was consistent over the 3‐year period, whereas migration return date was more variable and may be linked to river flow rate. No significant differences in distance covered between years were identified, but Lake Sturgeon tended to migrate longer distances in years when flow rates were higher. Finally, the spatial extent of Lake Sturgeon in the Saskatchewan River System appears to be larger than that of many previously studied river and lake populations. This study provides important insights into Lake Sturgeon distribution and migration patterns within large prairie rivers, increasing our basic knowledge of this unique fish species in understudied river systems, and provides important information for conservation within their historic range. Received January 16, 2014; accepted August 5, 2014