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Accounting for false mortality in telemetry tag applications


Bird, T and Lyon, J and Wotherspoon, S and King, R and McCarthy, M, Accounting for false mortality in telemetry tag applications, Ecological Modelling, 355 pp. 116-125. ISSN 0304-3800 (2017) [Refereed Article]

Copyright Statement

Copyright 2017 Elsevier B.V.

DOI: doi:10.1016/j.ecolmodel.2017.01.019


Deaths of animals in the wild are rarely observed directly, which often limits understanding of survival rates. Telemetry transmitters offer field ecologists the opportunity to observe mortality events in cases as the absence of animal movement. When observations of mortality are based on factors such as the absence of animal movement, live individuals can be mistaken for dead, resulting in biased estimates of survival. Additionally, tag failure or emigration might also influence estimates of survival in telemetry studies. Failing to account for mis-classification, tag failure, and emigration rates can result in overestimates of mortality rates by up two-fold, even when the data are corrected for obviously mistaken entries. We use a multi-state capture–recapture model with a misclassification parameter in estimating both the rate of permanent emigration and/or tag failure and the rate at which individuals are mistakenly identified as dead. We use this method on an annual telemetry survey of three species of native fish in the Murray river, Australia: Murray cod (Maccullochella peelii), trout cod (Maccullochella macquariensis) and golden perch (Macquaria ambigua). Evidence for higher mortality rates in the first year post-implantation occurred for Murray cod and golden perch, which is likely an effect of tagging and/or the transmitter, or transmitters shedding. Using simulations, we confirm that our model approach is robust to a broad range of misclassification and transmitter failure rates. With these simulations we also demonstrate that misclassification models that do not account for emigration will likely be erroneous if live and dead animals have different probabilities of detection. These findings will have a broad interest to ecologists wishing to account for multiple sources of misclassification error in capture-mark-recapture studies, with the caveat that the specifics of the approach are dependent on species, transmitter types and other aspects of experimental design which may or may not be amenable to the misclassification framework.

Item Details

Item Type:Refereed Article
Keywords:Murray cod, trout cod, golden perch, capture-recapture, telemetry, tag failure
Research Division:Mathematical Sciences
Research Group:Statistics
Research Field:Biostatistics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Wotherspoon, S (Dr Simon Wotherspoon)
ID Code:116833
Year Published:2017
Web of Science® Times Cited:6
Deposited By:Ecology and Biodiversity
Deposited On:2017-05-23
Last Modified:2018-05-28

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