Mountain Whitefish Overwintering Habitat Use in the McLeod River
Author(s)
Brittany Schmidt, Kevin Fitzsimmons, and Andrew Paul
Summary
As demand continues to grow for industrial, agricultural, and domestic water use, Albertans are seeking strategies to manage water needs into the future. One of the primary tasks in water management is determining the instream flow needs of an ecosystem so that managers can seek to meet socio-economic needs, while maintaining the ecological integrity of a watershed. In 2014-15, Alberta Environment and Parks (AEP) determined overwintering areas and microhabitat characteristics for mountain whitefish (MNWH) in the Wapiti River and developed a resource selection function (RSF) model to predict winter instream flow needs. Mountain whitefish were selected as a species of focus due to their tendency to occupy areas of faster moving water, which could make them more sensitive to changes in flow. The resulting RSF model showed MNWH were sensitive to water withdrawals during low winter flows. Alberta Conservation Association (ACA), in collaboration with AEP, developed the current project to validate the results from the Wapiti River. We conducted a telemetry survey on the McLeod River, where we tagged and tracked MNWH throughout the winter of 2017-18 to determine overwintering habitat. We collected under-ice habitat data at tagged fish locations, as well as at additional sites available to fish within the study area. We used this data to develop an RSF model to determine if MNWH overwintering habitat in the McLeod River could be predicted by a set of parameters. Results from our telemetry survey indicate that fish movement varied from 9 km upstream to 89 km downstream of initial tagging locations, with fish travelling greater distances from September to November than from November to March as they moved into overwintering habitat. Our RSF model found MNWH habitat use to be predicted by depth and dominant substrate, with fish showing preference for shallower habitats with larger particle sized substrate. Our data provides valuable information with regards to under-ice movement and overwintering habitat preference for MNWH and can be used in future management decisions with regards to winter instream flow needs.