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Dude, Where's my Transmitter? Probability of Radio Transmitter Detections and Locational Errors for Tracking River Fish
Author(s) -
Watkins Owen B.,
Paul Andrew J.,
Spencer Stephen C.,
Sullivan Michael G.,
Foote Lee
Publication year - 2019
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1002/nafm.10307
Subject(s) - transmitter , altitude (triangle) , remote sensing , radio transmitter design , environmental science , acoustics , computer science , telecommunications , physics , geography , mathematics , channel (broadcasting) , geometry
To simulate radio‐location tracking of fish in a lotic system, we deployed 148‐ MH z radio transmitters and measured signals from three altitudes over a known location. We examined detection distance, location error, and detection probability for two transmitter types at seven transmitter depths. We found that transmitter type, altitude, flight direction, and depth affected both detectability of transmitters and accuracy of locations. Maximum observed detection distance was 5,614 m for the small‐type transmitters at an altitude of 300 and 14,508 m for large‐type transmitters at an altitude of 600 m. Detection distances declined rapidly with increasing transmitter depth for both transmitter types. Locational errors ranged from 8 to 842 m (x¯ = 177 m; SE = 15.2) and were biased with flight direction. Detection probabilities declined with increasing transmitter depth and with increasing number of scanned frequencies. Scanning five frequencies, at the optimal flight altitude for a given transmitter type, resulted in nearly a 50% loss of detection probability at a 5‐m depth and a 90% decrease at a 7‐m depth. We recommend that researchers model their probability of detection a priori, all transmitters transmit on a single frequency, and a receiver altitude of 300 m should be maintained.