A Case Study Leveraging Angler Reported Data For Whirling Disease Monitoring

Abstract

The Bow River (Alberta, Canada) has a well-documented decline in its rainbow trout fishery, with several stressors attributed to this decline including whirling disease (WD). This study evaluated whether anglers could detect recruitment failure in WD-impacted areas of the Bow River drainage using a smartphone app-based citizen science initiative. Anglers reported age 1 and 2 rainbow and cutthroat trout identified by size distribution, estimated from a provincial database, across 4 sub-watersheds with varying densities of Myxobolus cerebralis actinospores (TAMs), a known predictor of WD severity. TAM densities ranged from undetectable (0 TAMs/L - Waiparous Creek) to moderate ( 0.01 TAMs/L - Jumpingpound Creek). No fish were captured in Jumpingpound Creek over 20.2 angling hours. The Highwood and Sheep Rivers had catch rates of 0.4 and 0.2 age 1 and 2 trout per hour over 30.6 and 27.7 hours, respectively. Waiparous Creek, where WD was absent, had a significantly higher catch rate of 2.2 trout per hour over 20.3 hours. These findings suggest that self-reported angler data can potentially help identify recruitment losses in WD-impacted areas, demonstrating a novel application of citizen science in fisheries research.