Acoustic Identification of Nine Delphinid Species in the Eastern Tropical Pacific Ocean

Oswald, Julie N.; Barlow, Jay; Norris, Thomas F.

doi:10.1111/j.1748-7692.2003.tb01090.x

Cited by 162 publications

(131 citation statements)

References 14 publications

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“…In line with other studies of bottlenose dolphin communication (Steiner 1981;Wang et al 1995a,b;Oswald et al 2003;Morisaka et al 2005), the duration and number of inflection points of whistles were highly variable (CVs of 58 and 133, respectively, Figure 7). As bottlenose dolphins develop individually distinctive signature whistles in the first year of life (Caldwell and Caldwell 1979;Caldwell et al 1990), the high variability in these parameters likely reflects differences in the individually distinctive signature whistles produced by group members (Kriesell et al 2014) and may also reflect differences in whistle characteristics due to varying behavioural state (Esch et al 2009a) or group composition (Caldwell et al 1990;Janik et al 2013) during encounters.…”

Section: Discussionsupporting

confidence: 72%

“…As minimum frequency appears to be relatively consistent across populations it may be a good parameter for determining species identity through PAM, particularly if the number of potentially whistling species are few, which is the case in Namibia. However, as the whistle parameters of many dolphin species overlap (Oswald et al 2003;Oswald et al 2007;Baron et al 2008), a more robust approach may be whistle classification based on multiple contour features (Gillespie et al 2013). Future PAM of dolphins in coastal Namibia can use the data collected during this study to train whistle classification systems.…”

Section: Discussionmentioning

confidence: 99%

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The acoustic repertoire of wild common bottlenose dolphins (Tursiops truncatus) in Walvis Bay, Namibia

et al. 2015

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Describing the repertoire of sounds produced by wild cetaceans is necessary for understanding their function, for acoustic population monitoring and for measuring the potential influence of anthropogenic impact. Geographic variation in the types and parameters of sounds makes regional assessment of vocal behaviour necessary. We describe the acoustic repertoire of a small population of common bottlenose dolphins (Tursiops truncatus) inhabiting Walvis Bay, Namibia from recordings made over 59 encounters (72 h) between 2009 and 2012. The characteristics of burst pulse (BP) sounds, low-frequency narrow-band (LFN) sounds, brays, whistles and chirps are described. The BP sounds identified were generated at 150-1050 pulses per second, and most were short, lasting less than 1 s in duration. Bottlenose dolphins from Walvis Bay produce the lowest frequency LFN sounds described for the species. Whistles ranged in frequency from 1.58 to 23.24 kHz, and the mean acoustic parameters were within the range of those described from other geographic regions. Chirps were identified infrequently and usually as single occurrences. Although several sound types were often produced in close temporal succession, we found little evidence of stereotyped bray production, even during recordings of animals feeding. Our results demonstrate geographic variation in both the characteristics and sound types used by bottlenose dolphins and highlight the importance of regional data collection as a pre-curser to passive acoustic monitoring programmes.

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Section: Discussionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

The acoustic repertoire of wild common bottlenose dolphins (Tursiops truncatus) in Walvis Bay, Namibia

et al. 2015

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“…Herman & Tavolga 1980, Au 1993. Field recordings of false killer whale and short-finned pilot whale whistles have been successfully discriminated, and automated classification routines were developed (Rendell et al 1999, Oswald et al 2003. However, misclassification most often occurred with whistles originating from shortfinned pilot whales.…”

Section: Introductionmentioning

confidence: 99%

False killer whale and short-finned pilot whale acoustic identification

Baumann‐Pickering¹,

Simonis²,

Oleson³

et al. 2015

Endang. Species. Res.

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(Jefferson et al. 2008), where long-line fishing is conducted. The behavior, ecology, and social structure of these species have been studied most extensively around the Hawaiian archipelago (Baird 2009 ABSTRACT: False killer whales Pseudorca crassidens and short-finned pilot whales Globicephala macrorhynchus are known to interact with long-line fishing gear in Hawaiian waters, causing economic loss and leading to whale injuries and deaths. The main Hawaiian Islands' insular population of false killer whales is listed as endangered and the offshore population is considered 'strategic' under the Marine Mammal Protection Act due to relatively high bycatch levels. Discriminating between these species acoustically is problematic due to similarity in the spectral content of their echolocation clicks. We used passive acoustic monitoring along with data from satellite tags to distinguish signals from these 2 species. Acoustic encounters recorded with autonomous instruments offshore of the islands of Hawai'i and Kaua'i were matched with concurrent and nearby location information obtained from satellite tagged individuals. Two patterns of echolocation clicks were established for the 2 species. The overall spectral click parameters were highly similar (22 kHz peak and 25 kHz center frequency), but false killer whales had shorter duration and broader bandwidth clicks than short-finned pilot whales (225 µs, 8 kHz [−3 dB bandwidth] and 545 µs, 4 kHz, respectively). Also, short-finned pilot whale clicks showed distinct spectral peaks at 12 and 18 kHz. Automated classification techniques using Gaussian mixture models had a 6.5% median error rate. Based on these findings for echolocation clicks and prior published work on whistle classification, acoustic encounters of false killer whales and short-finned pilot whales on autonomous instruments should be identifiable to species level, leading to better long-term monitoring with the goal of mitigating bycatch.

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“…With these characterizations we are planning on collaborations to enhance acoustic classifiers of FKWs and MHWs (e.g., Oswald et al 2003;Oswald et al 2004). Sound types will be compared to dive movement and behavior, examining prevalence of sounds in various parts of the dive as well as vocalization rates.…”

Section: Resultsmentioning

confidence: 99%

Acoustic Behavior, Baseline Ecology and Habitat Use of Pelagic Odontocete Species of Concern

Tyack¹,

Mooney²,

Baird³

et al. 2012

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LONG-TERM GOALSObtain critical sound use, behavioral ecology, and fine-scale habitat use information of two pelagic species of odontocete cetaceans which inhabit regions of significant U.S. Naval operations and may be impacted by coincident Naval training activities. The goal is to establish baseline acoustics, behavior and ecology of these species to predict and mitigate potential human impacts. Information gained will provide a context for evaluating natural behavioral ecology and potential responses to anthropogenic sounds. OBJECTIVESThrough detailed, non-invasive, bioacoustic behavior measurements:

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Acoustic Identification of Nine Delphinid Species in the Eastern Tropical Pacific Ocean

Cited by 162 publications

References 14 publications

The acoustic repertoire of wild common bottlenose dolphins (Tursiops truncatus) in Walvis Bay, Namibia

The acoustic repertoire of wild common bottlenose dolphins (Tursiops truncatus) in Walvis Bay, Namibia

False killer whale and short-finned pilot whale acoustic identification

Acoustic Behavior, Baseline Ecology and Habitat Use of Pelagic Odontocete Species of Concern

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