Movement of Lake‐Origin Burbot Reared in a Hatchery Environment and Released into a Large River Drainage

Abstract

AbstractBurbot Lota lota in Kootenay Lake and the Kootenay River of British Columbia, Idaho, and Montana (U.S. spelling: “Kootenai River”) are at risk of demographic extinction. We conducted a pilot study to evaluate poststocking dispersal and movement of hatchery‐reared, lake‐strain burbot (Moyie Lake, British Columbia) in a riverine environment to determine the potential utility of this hatchery strain for future burbot rehabilitation efforts in this system. We implanted ultrasonic tags into 30 hatchery‐reared burbot (ages 2 and 3) and released them into the Goat River, a tributary to the Kootenay River, in October 2009. Dispersal over a distance of 2 km from the Goat River release site to the Kootenay River occurred within 1–9 d after release (mean = 3.1 d; n = 28 active tags). Thereafter, 14 burbot remained in the Kootenay River for the rest of the 144‐d study period; nine of these fish were observed moving upstream from the Goat River confluence, and five were observed both upstream and downstream from the confluence. The other 14 burbot were observed in Kootenay Lake; of these fish, eight were detected in the lake for the duration of the study, and six were observed to move regularly between the lake and the river. Dispersal distances (distance between the upstream‐most and downstream‐most detections per individual) within the Kootenay River ranged from 10 to 138 km (mean = 80 km), and tagged fish were detected over a 236‐km reach (from 135 km downstream to 101 km upstream of the Goat River confluence). We also observed burbot in the vicinity of known spawning locations during the February spawning season. The observed dispersal suggests that a limited number of stocking locations may be sufficient to allow burbot to access available habitats within a few months postrelease. Our observations therefore suggest that lake‐origin, hatchery‐reared burbot may be suitable for stocking in a riverine environment.Received June 11, 2010; accepted December 4, 2010