Real-Time 2-Dimensional Fish Tracking in the Tailrace of a Hydroelectric Damreal-Time 2-Dimensional Fish Tracking in the Tailrace of a Hydroelectric Dam

A hydropower dam tailrace is a challenging environment for any fisheries sampling methodology.  Using acoustic telemetry to precisely position and track individual fish in 2-dimensions (2D) within these hydraulically dynamic regions would appear unfeasible.  The challenges to successful telemetry system performance in dam tailrace areas include significant levels of entrained air and turbulence, shallow water, large angular stream-bed substrate, and possible non-reverberant noise from power production.  These noise impacts can be minimized by using acoustic tags that are fully-programmable and utilize pulse-repetition period coding schemes.

A recently-conducted feasibility study was able to overcome these obstacles and demonstrated the ability to successfully track acoustic tags with 2-D resolution in a hydropower dam tailrace.  A system was deployed and tested at the site in a single day and demonstrated the ability to detect and position tags under high noise conditions.  Animated 2D tracks produced in real-time will be presented and compared with overlaid post-processed tracks.  Additional examples from acoustic tag assessments at other hydroelectric facilities located in North and South America will be presented.  These results demonstrate that acoustic tags using the pulse-repetition period method can provide an effective tool to monitor fish in complex and acoustically-noisy tailrace environments.