Habitat Used by Juvenile Lake Sturgeon Acipenser fulvescens in the North Channel of the St. Clair River (Michigan, USA)

Lake sturgeon (Acipenser fulvescens) occupy the St. Clair River, part of a channel connecting lakes Huron and Erie in the Laurentian Great Lakes. In the North Channel of the St. Clair River, juvenile lake sturgeon 3-7 years old (374–793 mm in length) were studied to determine movement patterns and habitat usage. Seventeen juveniles were implanted with ultrasonic transmitters and tracked June-August of 2004, 2005 and 2006. Telemetry data, Geographic Information Software, video images of the river bottom, and benthic substrate samples were used to determine the extent and composition of habitats they occupied. Juvenile lake sturgeon habitat selection was strongly related to water depth. Over 95% of the time, they occupied depths > 9 m; depths most commonly occupied were 12 -18 m (44% of occupied locations). All sturgeon showed a high degree of site fidelity; home range areas varied from 0.8 km² to 10.8 km². Many juvenile lake sturgeon had a high degree of home range overlap in areas that contained gravel bottom substrate without zebra mussels. Juvenile lake sturgeon home range was smaller in areas that contained gravel substrate than in areas covered with zebra mussels. A significant negative correlation was found between the amount of zebra mussel coverage and water depth. Bottom substrates at greater depths had lower zebra mussel coverage. Our findings are consistent with the hypothesis that juvenile lake sturgeon occupy deep areas of the North Channel because those areas lack zebra mussels and contain gravel substrates.