Modelling the broadband propagation of marine mammal echolocation clicks for click-based population density estimates
| Autor: | Leonard Joseph Thomas, Alexander M. von Benda-Beckmann, Peter L. Tyack, Michael A. Ainslie |
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| Přispěvatelé: | Office of Naval Research, University of St Andrews. School of Mathematics and Statistics, University of St Andrews. Marine Alliance for Science & Technology Scotland, University of St Andrews. Centre for Research into Ecological & Environmental Modelling, University of St Andrews. School of Biology, University of St Andrews. Centre for Social Learning & Cognitive Evolution, University of St Andrews. Sea Mammal Research Unit, University of St Andrews. Sound Tags Group, University of St Andrews. Bioacoustics group, University of St Andrews. Scottish Oceans Institute |
| Rok vydání: | 2018 |
| Předmět: |
Absorption (acoustics)
Passive acoustic monitoring Acoustics and Ultrasonics Computer science Bioacoustics QH301 Biology Acoustics NDAS Human echolocation 01 natural sciences Sonar Background noise QH301 03 medical and health sciences 0302 clinical medicine Narrowband Marine mammal Arts and Humanities (miscellaneous) 0103 physical sciences QA Mathematics SDG 14 - Life Below Water QA 030223 otorhinolaryngology 010301 acoustics Detector Noise |
| Zdroj: | The Journal of the Acoustical Society of America. 143:954-967 |
| ISSN: | 0001-4966 |
| Popis: | Funding: U.S. Office of Naval Research (ONR Grant No. N00014-14-1-0409); P.L.T. acknowledges funding received from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (Grant No. HR09011) and contributing institutions. Passive acoustic monitoring with widely-dispersed hydrophones has been suggested as a cost-effective method to monitor population densities of echolocating marine mammals. This requires an estimate of the area around each receiver over which vocalizations are detected—the “effective detection area” (EDA). In the absence of auxiliary measurements enabling estimation of the EDA, it can be modelled instead. Common simplifying model assumptions include approximating the spectrum of clicks by flat energy spectra, and neglecting the frequency-dependence of sound absorption within the click bandwidth (narrowband assumption), rendering the problem amenable to solution using the sonar equation. Here, it is investigated how these approximations affect the estimated EDA and their potential for biasing the estimated density. EDA was estimated using the passive sonar equation, and by applying detectors to simulated clicks injected into measurements of background noise. By comparing model predictions made using these two approaches for different spectral energy distributions of echolocation clicks, but identical click source energy level and detector settings, EDA differed by up to a factor of 2 for Blainville's beaked whales. Both methods predicted relative density bias due to narrowband assumptions ranged from 5% to more than 100%, depending on the species, detector settings, and noise conditions. Publisher PDF |
| Databáze: | OpenAIRE |
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