AUTHORS: Hannah Thomas, University of Illinois at Urbana-Champaign; Cali Engel, University of Nebraska-Lincoln; William Radigan, University of Nebraska-Lincoln; Dr. Mark Pegg, University of Nebraska-Lincoln; Chris Longhenry, South Dakota Department of Game, Fish, and Parks
ABSTRACT: Acoustic telemetry has become a common method to track fish movement patterns. Understanding the detection capacity of each receiver is a needed, but often overlooked aspect of acoustic telemetry studies. However, range tests can be used to assess detection capacities and ultimately the overall effectiveness of the receiver network. Recent range test investigations have evaluated the effects of distance, mount design, transmitter depth, transmitter model (V13 or V16) and wind speed on detection efficiencies. However, other environmental factors including human generated noise have not received as much attention. Range tests (n=122) were conducted between March 2022 and August 2024 at each of 14 receivers placed in the Missouri River and Lewis and Clark Lake to evaluate the effect of environment on detection efficiencies. Detection efficiencies were related to boater traffic, wind speed, distance from receiver, and seasonality. Detection efficiencies increased with decreasing distance between the tag and receiver and decreased noise interference from boat traffic and high-speed winds. Detection efficiencies were also found to vary among seasons, with spring showing increased detection efficiency compared to summer and fall. Mean detection efficiency at any given receiver and river kilometer was 34% during spring, compared to 25% in summer and 22% in fall. These findings provide valuable insights for future acoustic telemetry studies by highlighting important environmental factors that managers should consider when planning similar studies.
