Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8815
Title: Comparing the metabolic costs of different sound types in bottlenose dolphins
Author: Marla M. Holt, D. P. Noren, R. C. Dunkin, T. M. Williams
Publication Year: 2016
Journal: Proceedings of Meetings on Acoustics
Keywords: bottlenose dolphin,metabolic cost,sound production,whistles,clicks,Tursiops truncatus

Cetaceans produce different types of sounds that vary according to behavioral context.  They also modify their acoustic signals in response to noise.  The metabolic costs of producing social sounds and clicks were recently measured in two bottlenose dolphins using flow-through respirometry methods.  For both sound types, metabolic rates significantly increased as vocal effort increased, illustrating a modest cost of vocal modification.  Using these data, metabolic costs can be extrapolated to more typical (higher) values of free-ranging dolphins and compared among sound types.  However, cost comparisons are complicated by important differences in methodology and the acoustic energy output between sound type trials.  In this investigation, existing data are analyzed specifically to scale and compare costs with these differences taken into account.  Total metabolic cost of sound production was calculated above baseline values in ml O2 and related to vocal effort in dB re 1 µPa2s (adjusted to on-axis source levels) on a per trial basis.  Results reveal that clicks are produced at smaller costs compared to whistles.  These findings are consistent with the observation that whistles require higher intranasal air pressure during sound generation and allow estimates of the costs of responses across a range of behavioral contexts and disturbance scenarios.


Proceedings for the Effects of Noise on Aquatic Life Conference

Theme: Recovery and rebuilding of marine and coastal species
Foci: Describe the relationships between human activities and species recovery, rebuilding and sustainability.
Develop methods to use physiological, biological and behavioral information to predict population-level processes.