Cardiorespiratory Responses to Acoustic Noise in Belugas

Abstract

To date, most research on the adverse effects of anthropogenic noise on marine mammals has focused on auditory and behavioral responses. Other responses have received little attention and are often ignored. In this study, the effect of acoustic noise on heart rate was examined in captive belugas. The data suggest that (1) heart rate can be used as a measure of physiological response (including stress) to noise in belugas and other cetaceans, (2) cardiac response is influenced by parameters of noise and adaptation to repeated exposure, and (3) cetacean calves are more vulnerable to the adverse effect of noise than adults.

Heart rate regulation in diving sea lions: the vagus nerve rules

“…Based on our analysis of the literature, however, we suspect that the parasympathetic response will predominate in marine mammals during stress. In every case of which we are aware, when a diving animal was stressed, altered ascent and dove deeper, or was unable to access the surface to breathe, the animal maintained the apneic bradycardia or responded with a further decrease in heart rate (Andrews et al, 1997;Dormer et al, 1977;Fedak et al, 1988;Furilla and Jones, 1987;Jobsis et al, 2001;Kvadsheim et al, 2010;Lyamin et al, 2016;Meir et al, 2008;Murdaugh et al, 1961). Despite an increase in body acceleration and prolonged breathholding on exposure to pinger-like sounds, a marked bradycardia also occurred in harbor porpoises (Phocoena phocoena) (Teilmann et al, 2006).…”

Heart rates, heart rate profiles, and electrocardiograms in three killer whales, a beluga, and a pilot whale: An exploratory investigation

“…, Lyamin et al . ). In general, there was a three‐ to four‐fold difference between maximum and minimum heart rates under these conditions, similar to the approximate four‐fold range in heart rate reported in post‐escape dives of narwhals and routine dives of dolphins (Noren et al .…”

Heart rate and startle responses in diving, captive harbour porpoises (Phocoena phocoena) exposed to transient noise and sonar

“…Furthermore, in restrained captive belugas exposed to noise playbacks of a variety of frequencies, the first exposure had clear effects, albeit different, in three individuals: One responded with bradycardia, one with tachycardia, and one with a narrower range of f H . After repeated exposures, the cardiac response lessened for all three individuals ( Lyamin et al, 2016 ). While habituation of heart rate responses occurred rapidly in captivity, it is unknown if, or at what pace, this will occur in the wild, where acoustic stimuli often are novel and less predictable and where animals can flee.…”

“…While the cardiovascular response to an acoustic stressor in wild cetaceans has not been measured, the few studies on captive cetaceans have provided conflicting results with some individuals decreasing and others increasing f H , even within the same species. Such differing f H response types may relate to naivety, sound characteristics, and context ( Lyamin et al, 2016 ; Miksis et al, 2001 ; Teilmann et al, 2006 ). Cetaceans with a strong anti-predator response may be more likely to startle when exposed to certain noises ( Wright et al, 2007 ).…”