Moberly Lake Trout Rehabilitation Project

Here is the most recent report on the Moberly Lake trout rehabilitation project.

Executive Summary

Lake trout declines in Moberly Lake have been a matter of public concern since at least the early 1970’s. A series of standardised habitat assessments completed by Horne (2003) and Anderson (2007a) indicate that habitat quality is excellent, and that the long and varied history of harvest pressures was responsible for lake trout declines.

Lake trout stock assessment and mark-recapture work completed from 2005-2012 indicates that lake trout are at critically low abundance (less than 500 fish ? 35cm) and that a nearly total collapse in recruitment is occurring, the combination of which may lead to extirpation within a ten-year period (Anderson 2009).

The recruitment failures are believed to be the result of cultivation-depensation interactions within the larger fish community, and most likely involve lake whitefish (and/or perhaps slimy sculpins; Anderson 2009).

In collaboration with the Freshwater Fisheries Society of BC (FFSBC), a series of three rehabilitative stocking efforts have been undertaken in an effort to re-establish the species community balance in Moberly Lake and promote successful recruitment of lake trout to the population. To this end, the first successful egg-take was completed in fall 2010, using Moberly lake trout as brood stock. The progeny were hatchery-reared until release as large yearlings in the spring of 2012. The second egg-take was completed in the fall of 2012, again using native brood stock, with progeny intended for release in the spring of 2014. One last egg collection and subsequent stocking is planned for the fall of 2014 and spring of 2016 respectively.

The main intent of this report is to document the activities completed since the time of last reporting (2010-2012 inclusive), and provide an update on results of the continuing data analyses.

Complete Report