Lake Trout Spawning Site Utilization in Lake Champlain

After 60 years of restoration efforts in the Great Lakes and Lake Champlain, natural recruitment of lake trout (Salvelinus namaycush) populations is still limited. Despite years of research, we still know very little about basic spawning behavior and movements of this species. Males are more abundant than females on spawning sites early in the spawning season and may use the same sites year after year. We hypothesize that males will show site fidelity and remain at a preferred site during the spawning season, whereas females will 'sample' multiple spawning reefs to maximize their reproductive success. This hypothesis will be supported if males spend more time on spawning sites than females, visit fewer sites than females, and return to the same site year after year.  We deployed 27 receivers in Lake Champlain to study lake-wide movements at multiple, discrete spawning sites.  We used a novel approach of defining site residence without a VPS array using real-time detection probabilities of onsite sentinel tags. Data to date suggest both sexes visit multiple sites, but select a preferred spawning site where they spend the majority of the spawning season. Data from future years will determine the degree of spawning site fidelity by each sex.