Seasonal Movements and Spatial Overlap of Juvenile and Adult Lake Sturgeon in Lake Champlain

Abstract

The lake sturgeon Acipenser fulvescens is a large, long-lived, potamodromous species that is widely distributed throughout freshwater systems in the central part of North America. In this study, we used acoustic telemetry to examine seasonal distribution and movement patterns of endangered Lake Sturgeon in Lake Champlain, Vermont. Acoustic tags were implanted in 29 juvenile Lake Sturgeon (453-874 mm TL) and 19 adults (1,215-1,615 mm TL) from the Winooski River and nearby areas of Lake Champlain between 2015 and 2019; tags were detected with 23 passive acoustic receivers deployed in the river and delta area and an additional 34 receivers deployed throughout Lake Champlain. Home range analysis using a lattice-based density estimator indicated that juvenile home range sizes were the same as adult home range sizes in spring and summer but were statistically larger than adult home ranges in winter. Cumulative home range analysis showed that juvenile and adult home ranges overlapped in shallow (<10-m) water in the summer and fall. In winter and spring, cumulative home ranges from juveniles included deepwater sites (>25 m), while adults remained in shallow water near the mouth of their spawning river. Seven juveniles made longrange movements (18-34 km) during the winter and spring months, and 13 juveniles moved back into the lower section of their natal river after overwintering in Lake Champlain. This study is the first to directly compare adult and juvenile Lake Sturgeon distribution, home range size, movements, and habitat use in a large lake system and provides a baseline for further research on the movement ecology of Lake Sturgeon in Lake Champlain.

Movement, home range, and structural habitat use of the Largemouth Bass complex in two large Texas reservoirs

“…2022; Izzo et al. 2022). The lattice‐based method applies a random walk across a lattice of nodes accounting for only the usable habitat (i.e., submerged habitat that is not on land) to estimate activity space.…”

“…Home range was calculated from relocations of individual fish by using a lattice-based density estimator within the R package LatticeDensity (Barry and McIntyre 2011). The lattice-based density estimation method was chosen over traditional kernel estimation due to the ability to account for the irregular boundaries of the study sites as well as holes (i.e., islands) within those boundaries; this method is commonly applied by telemetry studies evaluating fish activity (Kneebone et al 2012;Hollema et al 2017;Legare et al 2018;Edwards et al 2022;Izzo et al 2022). The lattice-based method applies a random walk across a lattice of nodes accounting for only the usable habitat (i.e., submerged habitat that is not on land) to estimate activity space.…”

“…Within the lattice applied across each study area, we applied a node spacing of 50 m (Izzo et al 2022) while keeping each lattice uniform enough to perform estimations. Estimation of an optimal smoothing parameter (k) was applied using a fixed value across every fish, as is commonly employed after visual inspection of a range of k-values (Kneebone et al 2012;Hollema et al 2017;Legare et al 2018;Edwards et al 2022;Izzo et al 2022). A k-value of 5 was chosen for the estimation of each home range.…”