Echolocation by marine delphinids and one species of fresh-water dolphin

Evans, William E.

doi:10.1121/1.1913562

Cited by 152 publications

(109 citation statements)

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“…The target detection and discrimination abilities of captive dolphins and harbor porpoises (Phocoena phocoena) were later described in much greater detail . In addition, porpoises, like bats, have been shown to be able to navigate through mazes of thin wires with no or few collisions, again suggesting a role for echolocation in navigation and obstacle avoidance (Evans, 1973). More recently, Verfuss and colleagues (2005) further described captive porpoise click emission rates during navigation; their data indicate that porpoises use specific landmarks for orientation, and provide more evidence that porpoises use echolocation for navigation as well as foraging.…”

Section: General Overview Of Animal Echolocationmentioning

confidence: 94%

“…Early demonstrations of echolocation ability in cetaceans included the abilities of Amazon River dolphins (Inia geoffrensis) and bottlenose dolphins (Tursiops truncatus) to detect and discriminate between pairs of targets while blindfolded or in the dark; the animals produced broadband clicks as they performed the tasks (Norris, 1969;Evans, 1973). Those experiments suggested a possible role for echolocation in prey detection and selection.…”

Section: General Overview Of Animal Echolocationmentioning

confidence: 99%

“…A few species of toothed whales have been shown experimentally to use echolocation for navigation or for prey detection and capture, and most other odontocetes produce sounds potentially useful for echolocation (Evans, 1973;. A sequence of events analogous to that described for bats has been recorded from echolocating narwhals Buzz production rate has been proposed as a proxy for toothed whale foraging success rate (Miller et al, 2004;Watwood et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…A few species of odontocetes (toothed whales) have been shown experimentally to use echolocation for navigation or for prey detection and capture, and most other odontocetes produce sounds potentially useful for echolocation (Evans, 1973;. Early demonstrations of echolocation ability in cetaceans included the abilities of Amazon River dolphins (Inia geoffrensis) and bottlenose dolphins (Tursiops truncatus) to detect and discriminate between pairs of targets while blindfolded or in the dark; the animals produced broadband clicks as they performed the tasks (Norris, 1969;Evans, 1973).…”

Section: General Overview Of Animal Echolocationmentioning

confidence: 99%

“…Combined, these features may allow researchers to distinguish successful prey capture attempts from unsuccessful ones on the basis of acoustic data alone, without requiring high-resolution visual observations of each prey capture attempt. Accurate estimates of bat foraging success could thus be derived from acoustic recordings.A few species of toothed whales have been shown experimentally to use echolocation for navigation or for prey detection and capture, and most other odontocetes produce sounds potentially useful for echolocation (Evans, 1973;. A sequence of events analogous to that described for bats has been recorded from echolocating narwhals Buzz production rate has been proposed as a proxy for toothed whale foraging success rate (Miller et al, 2004;Watwood et al, 2006).…”

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confidence: 99%

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Echolocation-based foraging by harbor porpoises and sperm whales, including effects of noise and acoustic propagation

DeRuiter¹

2008

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In this thesis, I provide quantitative descriptions of toothed whale echolocation and foraging behavior, including assessment of the effects of noise on foraging behavior and the potential influence of ocean acoustic propagation conditions on biosonar detection ranges and whale noise exposure. In addition to presenting some novel basic science findings, the case studies presented in this thesis have implications for future work and for management.In Chapter 2, I describe the application of a modified version of the Dtag to studies of harbor porpoise echolocation behavior. The study results indicate how porpoises vary the rate and level of their echolocation clicks during prey capture events; detail the differences in echolocation behavior between different animals and in response to differences in prey fish; and show that, unlike bats, porpoises continue their echolocation buzz after the moment of prey capture.Chapters 3-4 provide case studies that emphasize the importance of applying realistic models of ocean acoustic propagation in marine mammal studies. These chapters illustrate that, although using geometric spreading approximations to predict communication/target detection ranges or noise exposure levels is appropriate in some cases, it can result in large errors in other cases, particularly in situations where refraction in the water column or multi-path acoustic propagation are significant.Finally, in Chapter 5, I describe two methods for statistical analysis of whale behavior data, the rotation test and a semi-Markov chain model. I apply those methods to test for changes in sperm whale foraging behavior in response to airgun noise exposure. Test results indicate that, despite the low-level exposures experienced by the whales in the study, some (but not all) of them reduced their buzz production rates and altered other foraging behavior parameters in response to the airgun exposure. Sincere thanks also to the many other people who have helped with data collection and analysis over the course of my graduate work, and also to everyone who offered comments on drafts of this thesis. More detailed acknowledgments can be found at the end of each chapter, but here I would especially like to thank the following. Thesis Objectives and Chapter 1 OverviewThe goal of my thesis research has been to provide quantitative descriptions of toothed whale echolocation and foraging behavior (Chapters 2 and 5), including assessment of the effects of noise on foraging behavior (Chapter 5) and the potential influence of ocean acoustic propagation conditions on biosonar detection ranges (Chapter 3) and whale noise exposure (Chapter 4). I have focused on two study species, the harbor porpoise (Phocoena phocoena, Chapters 2-3) and the sperm whale (Physeter macrocephalus, Chapters 4-5).The following sections present background information relevant to the research presented in the rest of the thesis, beginning with a review of previous research on the use of echolocation by foraging animals. This review is followed by b...

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Section: General Overview Of Animal Echolocationmentioning

confidence: 94%

Section: General Overview Of Animal Echolocationmentioning

confidence: 99%