WITHDRAWN: Receiver mount design, tag depth, and wind speed affect detection probability of acoustic telemetry tags in a Missouri River tributary

Abstract

Background One of the most important considerations for acoustic telemetry study designs is detection probability between the transmitter and the receiver. Variation in river conditions and flow regimes among river systems can lead to differences in detection probability between systems. In this study we evaluate the detection probabilities of two acoustic tag models at various distances from stationary receivers, for two different mount designs, at two different tag depths, and across varying wind speed. InnovaSea V16-6H (hereafter V16) and V13-1L (hereafter V13) tags were deployed in the James River, SD at a deep depth of 0.36 m above the benthic surface or at shallow depths of 2.29 m (V16 tag) or 1.98 m (V13 tag) above the benthic surface downstream of stationary receivers at distances of 100, 200, or 300 m. Two receiver mount designs that included a fixed position on bridge pilings in a PVC pipe or in a midriver frame, were used to detect acoustic signals. Tags were deployed for 72 hrs at each location, and hourly detections were summarized and compared to the expected number. We assessed downstream distance, receiver mount design, tag depth, and wind effects on tag detection using Bayesian logistic regression. Results Tag detection was high (>70%) at 100 m, >50% at 200 m, and lowest but variable at 300 m for the V16 tags. Tag detection was nearly 100% at 100 m, >50% at 200 m, and <10% at 100 m for the V13 tags. Detection probability was improved for the pipe mount when V16 tags were deployed at deep locations. There was no effect of tag depth or receiver design for the V13 tags. Wind had a strong, negative effect on the shallow V16 tag but no effect on the V13 tag. Conclusions Overall, mounting the receiver in a PVC pipe was more secure, and detection probability was greater for the V16 tag than the V13 tags. This study demonstrates the detectability of acoustic telemetry tags to downstream distances of at least 200 m in a Missouri River tributary.