Field Tests of Two Acoustic Telemetry Systems to Examine Range and Detection Efficiency

In an effort to better understand the performance of acoustic telemetry systems in environments where juvenile salmon studies are often conducted, we collected empirical data in the Snake and Columbia rivers. The objective of our tests was to determine the detection efficiency and range of two acoustic telemetry systems (Vemco and Advanced Telemetry Systems (ATS)) commonly used in the Columbia River Basin and Puget Sound. We used VR2W receivers (n=2) and V7-2L transmitters (n=20) made by Vemco and Juvenile Salmon Acoustic Telemetry System (JSATS) Trident SR3000 receivers (n=2) and SS300 transmitters (n=20) made by ATS.  Receivers were deployed in both a deep-slow reservoir forebay and a shallower tailrace area with more velocity. Fixed range and moving tests were performed with all of the transmitters deployed between 2 and 4 m below the water surface.  Additional data were collected to better understand the influence of multiple V7 transmitters on DE. The Vemco system appears well suited to studies involving larger, and slower moving organisms in areas where few tagged animals will be in range of receivers simultaneously. The JSATS is better suited for conditions in which larger numbers of smaller tagged organisms may be rapidly passing receiver locations.