Quantifying Summer Residency Times and Variation in Diel Behaviors of Lake Sturgeon in Buffalo Harbor, NY

Lake Sturgeon (Acipenser fulvescens) populations in easternmost Lake Erie were assumed functionally extirpated following the closure of the commercial fishery in the 1900’s. Remnant aggregations have been documented near the upper Niagara River. However, information about residency and movement within the adjoining Buffalo Harbor area of Lake Erie is deficient largely due to the dearth of these fish in targeted surveys. To inform future catch survey designs, we examined temporospatial diving and residency behaviors within the harbor. We surgically implanted 19 Lake Sturgeon with 69kHz acoustic transponders. These units transmitted pressure and location data to an array of Vemco© VR2W acoustic receivers that were deployed along the harbor from May to September 2015. We found that distance and depth changes were most dramatic in the late evening/early morning hours. Fish were relatively quiescent in the late morning/early evening. The majority of fish used the harbor extensively in the summer even after the spawning season ended. These findings support the hypothesis that Lake Sturgeon use the harbor outside of the spawning season, but are more active at night, which likely explains their apparent scarcity in surveys conducted during daytime hours. Future catch efforts should be coordinated with respect to these behaviors.