Lake whitefish (Coregonus clupeaformis) are ecologically, economically, and culturally significant across their range, yet little is documented about the species' spawning behaviour. Recruitment of lake whitefish has dramatically declined over the past two decades across many regions of the Laurentian Great Lakes, most notably in lakes Huron and Michigan, prompting research efforts to fill critical knowledge gaps in the life history of this species. Understanding the reproductive ecology of lake whitefish, including documenting aspects of spawning behaviour, may reveal clues about factors contributing to the declines. This study used fine-scale acoustic telemetry to characterize sex-specific movement patterns and habitat associations of lake whitefish during the spawning season. A VEMCO Positioning System (VPS) was deployed at an active spawning shoal in Georgian Bay (Lake Huron), with guidance provided by Saugeen Ojibway Nation members with local ecological knowledge about the shoal and the lake whitefish population. In the fall of 2020, 50 lake whitefish were captured and tagged at the spawning shoal; 28 of those fish were observed the following spawning season in 2021. A clear increase and decrease was observed in the presence of individuals in the study area over the spawning period. Both sexes moved into shallower waters at night and deeper waters during the day at rates of 0.162 m/h and 0.08 m/h, respectively. Decreased rates of movement and horizontal distance travelled were detected during the day leading up to a peak activity phase where 22 fish were present. At night during this peak activity phase, males moved 30.0% faster on average than females (0.204 ± 0.13 and 0.143 ± 0.10 m/s, respectively). This study provided a unique opportunity to work with local First Nations to understand lake whitefish spawning behaviour, providing insights into the reproductive ecology of a population undergoing concerning declines in recruitment and abundance.
Author Keywords: Coregonine restoration, Coregonus clupeaformis, Fine-scale acoustic telemetry, GLATOS, Spawning habitat, Two-Eyed Seeing