Detection Efficiency of Acoustic Transmitters at Priority Locations within Lake Sharpe

Determining fish movements using acoustic telemetry can only be reliably estimated if there is high probability of detecting tagged fish within the study area (i.e., detection efficiency, DE). The objective of this study was to determine the effective range of two Vemco acoustic transmitters with different power outputs (dB) to Vemco VR2W stationary receivers at two backwater locations in Lake Sharpe, South Dakota. In 2015, during late August and early September, Vemco transmitters were placed at fixed distances from receivers for 24-72 h and DE quantified. At site one, DE for both tags was >90% out to 274 m. At site two, DE for both tags was >90% at 137 m, which is the maximum distance from the receiver to shore. In both instances, night time DE was greater than daytime DE and low power tags performed better than high power tags in both locations. While tag detections at site two provide a reliable estimate of fish movement since >90% DE was achieved at all ranges and tag types, further testing at distances > 274 m will be completed in 2016 at locations where distances from the receiver to shore are greater than 274 m.