Large- and small-scale movement and distribution of acoustically tagged lake sturgeon (Acipenser fulvescens) in eastern Lake Erie

Abstract

Background Defining the spatial distribution, home range, and movement patterns of lake sturgeon ( Acipenser fulvescens ) is important to managers and decision-makers given the large migration potential and potamodromous behavior exhibited by the species. A remnant population of lake sturgeon remains in the far eastern basin of Lake Erie and although recent efforts have estimated the population size, described the age distribution, and identified a primary spawning site no study to date has examined the spatial distribution or movements of individuals within this population. Between 2014 and 2018, we acoustically tagged 59 adult lake sturgeon, captured in the Buffalo Harbor area, and monitored their large-scale movements throughout Lake Erie with the Great Lakes Acoustic Telemetry System and small-scale movements with a Vemco Positioning System in the Buffalo Harbor area. After dividing Lake Erie into seven sections, we ran a multi-state mark–recapture model to examine the movement rates into and out of the eastern most section of the lake. Within a heavily utilized lake section, in the Buffalo Harbor area, we identified home ranges with our Vemco Positioning System for each season and year using averaged Brownian bridge movement models. Results Although some sturgeon demonstrated large-scale movements, traversing the entirety of Lake Erie, the majority of individuals spent their time in the eastern basin of the lake. Home ranges appeared to vary among seasons, but were consistent across years with lake sturgeon selecting the northeastern, rocky, and shallow area of our array during pre-spawning and spawning seasons and leaving our array, or selecting a trough running along the northwestern portion of our array comprising sand and bedrock, in the summer and fall seasons. Conclusions Documenting these large-scale movements aligns with previous findings that lake sturgeon on either end of the lake are genetically similar and demonstrates lake sturgeon in the eastern basin exhibit strong philopatry. Our small-scale movement models provide managers with spatial reference points, in the form of utilization distributions, indicating heavily used areas by lake sturgeon within seasons. Future studies should examine what parameters are driving site selection in these areas.