Sturgeon Restoration in Lake Michigan Through Fish Passage: Efficacy of Attraction Flows on Upstream Passage

Lake sturgeon (Acipenser fulvescens) were once abundant in Lake Michigan and had unobstructed access to feeding and spawning areas within its many tributaries. Hydroelectric dams now impede much of this access, contributing to a more than 99% decline in the population. One method for re-establishing this lost connection is to create an artificial pathway around the dams (i.e., fishway). Working in collaboration with two of the dam's owners, We Energies and North American Hydro, we conducted two experiments to test efficacy of attraction flows on lake sturgeon in the Menominee River, a major tributary to Lake Michigan.  The Menominee River forms the border between northern Wisconsin and Michigan’s Upper Peninsula.  Our first experiment tested how well sturgeon attract to various flow rates within an empty turbine bay of an existing hydroelectric dam.  Results show that even with a modest attraction flow (approximately 2% of river flow) sturgeon would enter the turbine bay within minutes of flow application.  In our second experiment, we used a prototype fishway channel, suspended downstream of the discharge from a hydroelectric dam, to test whether we could attract sturgeon into an enclosed trap near the river’s surface using a constant attraction flow (approximately 4% of river flow) and a target velocity (approximately 1.07 meters per second).  The prototype fishway channel, fitted with a trap, was 1.5 m wide and 1.5 m deep and was suspended approximately 1.83 m from the river bottom with a ramping screen leading from the river bottom to the fishway channel.  Video and Passive Integrated Transponder (PIT) telemetry results show nearly 20% of the sturgeon population were attracted up into the fishway channel and passed through a 45.7 cm wide V-trap opening without hesitation. Overall, results from our studies indicate that sturgeon can be successfully attracted into a fishway using a designed flow and show the ability to be trapped if necessary.  Future tests to further evaluate their ability to be trapped are planned.