Habitat Utilization and Influences on Dispersal of Young-of-Year Lake Sturgeon (Acipenser fulvescens) in the Great Lakes Connecting Channels

The identification and protection of nursery habitat utilized by post-drift larval and young-of-year lake sturgeon has been designated as a top priority in the Great Lakes Basin. In the Great Lakes Connecting Channels, most studies have focused on adult and juvenile (>300mm) lake sturgeon, with relatively little attention being given to earlier life-stages, resulting in a gap in knowledge of lake sturgeon-environmental connectivity through their early life history development. This study examined the influence of both abiotic and biotic influences on the distribution of larval and YOY lake sturgeon in the St. Clair River System. Larvae were found to reside in the ~1-2 km stretch of the river between their spawning point of origin and the river mouth, for a period of 2-3 weeks and were found in greater abundance in smaller, low-flow velocity, secondary channels, suggesting that larvae may not just passively drift downstream but are actively selecting preferred sites. Georeferenced habitat information on substrate, invertebrate composition, flow, and depth collected in this system was used to construct a habitat suitability index in a GIS to produce spatially explicit models, predicting the location and abundance of suitable YOY and juvenile life stage specific habitat in the St. Clair River.