High prevalence of basin fidelity and homing by lake trout, Salvelinus namaycush, in a small northern lake

Abstract

Identifying how habitat structure influences the spatio-temporal movements of fishes is important for conservation, population assessment, and management purposes. Here, we determined whether acoustically tagged lake trout, Salvelinus namaycush, from a 305 ha lake exhibited homing behaviour and lake basin fidelity over multiple seasons and years. The lake has two distinct deep basins (‘north’ and ‘south’) connected by a shallower centre basin. Fifteen lake trout captured during the spawning season from both deep basins were tagged and released in the south basin. All translocated north-basin fish quickly returned to the north basin (median= 1.85 d, range= 0.36–4.5 d), apart from one fish that returned 41 d post-release, while none from the south ventured into the north basin during this time. After translocated individuals returned, all fish demonstrated high basin fidelity among years as >90% of detections were from the same basin fish were captured, while <0.7% (by three fish) were from the opposite deep basin and <9% from the centre basin. The probability a fish was detected outside its basin of capture was highest in winter (15.9%) and fall (14.3%), and lowest in summer (0.41%).