Tracking Lake Trout Habitat Use Using A New Telemetry Approach

The study of habitat use by fish has advanced through the use of acoustic telemetry. This technique allows the continuous monitoring of fish implanted with acoustic transmitters that send information to stationary receivers deployed in the water bodies. More recently, transmitters that measure acceleration have allowed us to describe habitat-specific activity in fish. These transmitters can also be used to estimate metabolic rates because acceleration is directly proportional to swimming speed, which is associated to oxygen consumption during active metabolism in fish. In this study we employed acceleration – depth transmitters to quantify the energetic costs of habitat use by Lake Trout, a cold-water top predator, across a suite of lakes differing in forage species. Lake Trout showed high variability in depth occupancy across the four study lakes. In general they occupied depths that matched their expected thermal and dissolved oxygen preferendum; however, we also observed frequent high-acceleration excursions to shallower or deeper parts of the lake. Activity estimates corresponded well with changes in depth, revealing a positive relationship between these two variables. By using these transmitters we were able to track habitat use by Lake Trout and link specific behaviours to metabolic costs. This telemetry technique has improved out ability to track energy expenditure associated to swimming behaviours in fish.