Handling dolphin detections from C-PODs, with the development of acoustic parameters for verification and the exploration of species identification possibilities
- 30 December 2015
- journal article
- research article
- Published by Taylor & Francis Ltd in Bioacoustics
- Vol. 25 (2), 99-110
- https://doi.org/10.1080/09524622.2015.1125789
Abstract
C-PODs are static passive acoustic monitoring devices used to detect odontocete vocalizations in the range of 20–160 kHz. However, falsely classified detections may be an issue, particularly with broadband species (i.e. many dolphin species) due to anthropogenic and other noise occurring at the same frequency. While porpoise detections are verified using species-specific acoustic parameters, the equivalent does not currently exist for verifying dolphin detections. Development of such parameters would increase the accuracy of dolphin detections and eliminate the need for additional monitoring techniques or devices, reducing the cost of monitoring programmes. Herein, we present parameters based on acoustic characteristics of bottlenose (n = 29), common (n = 19) and Risso’s (n = 99) dolphin click trains, sighted within 1 km of C-PODs during land-based surveys, for in-software verification. Overlap of click train parameters among dolphin species prevented robust species identification; therefore, parameters were devised for these dolphin species collectively using frequency, inter-click interval and click train duration. A data set of 4898 Detection Positive Hours was visually verified using these parameters. The temporal and spatial patterns in the visually verified data were similar to land-based observations, suggesting the parameters operate at an acceptable accuracy. However, 68% of high-, moderate- and low-quality KERNO detections were false-positive. Our results suggest that the accuracy of classifiers and quality class weightings are site-specific, and we highlight the importance of data exploration to make the most appropriate software choices based on the aims of a study.Keywords
This publication has 16 references indexed in Scilit:
- Acoustic detection probability of bottlenose dolphins, Tursiops truncatus, with static acoustic dataloggers in Cardigan Bay, WalesThe Journal of the Acoustical Society of America, 2013
- Methodology and results of calibration of tonal click detectors for small odontocetes (C-PODs)The Journal of the Acoustical Society of America, 2013
- Identifying Foraging Behaviour of Wild Bottlenose Dolphins (Tursiops truncatus) and Harbour Porpoises (Phocoena phocoena) with Static Acoustic DataloggersAquatic Mammals, 2013
- Whistle characteristics in free-ranging bottlenose dolphins (Tursiops truncatus) in the Mediterranean Sea: Influence of behaviourMammalian Biology - Zeitschrift fur Saugetierkunde, 2011
- Acoustic masking in marine ecosystems: intuitions, analysis, and implicationMarine Ecology Progress Series, 2009
- Echolocation signals of wild harbour porpoises,Phocoena phocoenaJournal of Experimental Biology, 2007
- Ecology, status and conservation of short‐beaked common dolphins Delphinus delphis in the Mediterranean SeaMammal Review, 2003
- Identifying critical areas and habitat preferences of bottlenose dolphins Tursiops truncatusMarine Ecology Progress Series, 2002
- Environmental Models of Cetacean Abundance: Reducing Uncertainty in Population TrendsConservation Biology, 2000
- Habitat Use by Bottlenose Dolphins: Seasonal Distribution and Stratified Movement Patterns in the Moray Firth, ScotlandJournal of Applied Ecology, 1997