The frequency of spawning and skipped migration in a central Canadian population of anadromous Arctic char inferred using acoustic telemetry

Understanding spawning frequency and migration behaviour is essential for managing iteroparous anadromous fishes such as Arctic char (Salvelinus alpinus). Using a decade of acoustic telemetry data from southern Victoria Island, Nunavut, we examined the frequency of marine migrations and inferred spawning events in Arctic char. Many individuals (128 of 256 fish) skipped marine foraging migrations every two to four years, instead remaining in freshwater during summer or making only brief marine transits—patterns consistent with reported spawning intervals in other populations and likely associated with spawning events, although spawning was not directly observed. These results suggest that Arctic char in this region do not spawn annually, reflecting the high energetic costs of reproduction and limited feeding opportunities in Arctic environments. Our findings demonstrate the flexible life-history tactics Arctic char employ to cope with extreme seasonality in resource availability. While telemetry offers valuable insight into migration and reproductive behaviour, confirming spawning events and interpreting short marine excursions remain challenging. Integrating telemetry with otolith microchemistry, genomics, and extended tracking will further clarify reproductive and foraging ecology. As Arctic conditions continue to change, such knowledge is critical to the sustainable management and conservation of this culturally and economically important species.