Assessment of a Constructed Fish Migration Barrier Using Radio Telemetry and Floy Tagging

Abstract

We assessed the effectiveness of a constructed fish migration barrier in the Salmo River, British Columbia, Canada, 10 years after it was constructed. The barrier was initially installed to prevent an expected increase in upstream migration of suckers Catostomus spp. and northern pikeminnow Ptychocheilus oregonensis into the Salmo River following the creation of Seven Mile Reservoir on the Pend d'Oreille River. To determine the effectiveness of the barrier, we applied radio and Floy tags to these species in Seven Mile Reservoir to assess whether upstream migration over the barrier was occurring. After sampling below the barrier, 5 largescale suckers C. macrocheilus and 5 northern pikeminnow were radio-tagged, whereas 124 suckers and 11 northern pikeminnow were Floy-tagged. Radio tracking surveys confirmed that most radio-tagged suckers and northern pikeminnow made migrations only within the reservoir, but one sucker was tracked above the barrier. This movement occurred after the peak of annual discharge. During snorkel surveys conducted above the barrier, we observed five Floy-tagged suckers. The results are discussed in relation to the use of tagging methods to monitor sucker and northern pikeminnow migrations and assess the effectiveness of constructed fish migration barriers.