Weilgart, Linda S. 2007.
Observed effects of noise on marine mammals include: changes in vocalizations, respiration, swim speed, diving, and foraging behavior; displacement, avoidance, shifts in migration path, stress, hearing damage, and strandings. Responses of marine mammals to noise can often be subtle and barely detectable, and there are many documented cases of apparent tolerance of noise. However, marine mammals showing no obvious avoidance or changes in activities may still suffer important, even lethal, consequences.
Hatch and Wright, 2007.
Sound in the oceans is generated by a variety of natural sources, such as breaking waves, rain, and marine animals, as well as a variety of human-produced sources, such as ships, sonars and seismic signals. This paper provides a basic introduction to the sources and physics of underwater sound for the uninitiated audience and provide references for the interested reader to gain additional information.
Hildebrand, John A.
There is sufficient evidence to conclude that some high-intensity sounds are harmful and, on occasion, fatal to marine mammals. Evidence suggests that given the opportunity, marine mammals avoid high-intensity sound. Damage to marine mammal hearing due to anthropogenic sound exposure has been documented in some extreme cases. Multiple mass-strandings of beaked whales following high-intensity sound exposure demonstrate a repeated pattern of events. Following exposure to high-intensity sonar or airguns, beaked whales have been known to strand on the shore, and these animals die if not returned to the sea by human intervention.
Moore and Stafford,
Ambient Noise Budgets and Acoustic Detection of Cetaceans in the North Pacific and Gulf of Alaska. Advancement of Detection and Prediction tools and Transfer to Navy & NOAA staff
Vladimir V. Popov, et al, 2007.
The two soundreceiving areas acoustic windows have different frequency sensitivities. In all studies of acoustic window localization performed before, wideband acoustic probes were used. So depending on stimulus parameters and experimental design, either of these two areas could be detected,
Finneran and Schlundt, 2007.
Experiments were conducted in a vinyl-walled, seawater-filled pool approximately 3.7 61.5 m. Acoustic signals were pure tone and linear and sinusoidal frequency modulated tones with bandwidths/modulation depths of 1%, 2%, 5%, 10%, and 20%. Hearing thresholds were measured using a behavioral response paradigm and up/down staircase technique. All three audiograms revealed significant high frequency hearing loss above 40 kHz, similar to that reported in prior behavioral and evoked potential hearing tests.
Nowacek, et al, 2007
We are concerned about the lack of investigation into the potential effects of prevalent noise sources such as commercial sonars, depth finders and fisheries acoustics gear. Furthermore, we were surprised at the number of experiments that failed to report any information about the sound exposure experienced by their experimental subjects. Conducting experiments with cetaceans is challenging and opportunities are limited, so use of the latter should be maximized and include rigorous measurements and or modelling of exposure. We focus in detail on those studies that report quantitatively on both the sound field as well as some indicator of response, i.e. received sound characteristics associated with behavioural or physiological response(s). Studies that did not report sound exposure at the location(s) of the animal(s) are not specifically reviewed, because results are almost impossible to interpret; i.e. measured or modelled characteristics of the received sounds (‘received level’ or RL) are critical to the interpretation of animal(s) responses or lack thereof.
As a means of assessing the degree of masking of a variety of industrial noises, animal experiments are inefficient because of the amount of time and cost involved. It would be preferable to have a fast, ground-truthed model simulating masked hearing experiments and thus predicting maskin o effects in cases where direct experiments with animals are infeasible.
The more subtle effects such as masking, annoyance and changes in behavior are often overlooked, especially in animals, because these subtleties can be very difficult to detect. many consequences of exposure to noise can result in a cascade of secondary stressors such as increasing the ambiguity in received signals or causing animals to leave a resourceful area, all with potential negative if not disastrous consequences.
Wardle, et al, 2000
Observations of marine fish and invertebrates on an inshore reef were made using TV and acoustic tags one week before, during, and four days after a seismic triple G. airgun (three synchronised airguns, each gun 2.5l and 2000psi) was deployed and repeatedly fired. The guns were fired once/min for eight periods on four days at different positions. The structure and intensity of the sound of each triple G. gun explosion was recorded and calibrated. Peak sound pressure levels of 210dB (rel to 1mPa) at 16m range and 195dB (rel to 1mPa) at 109m range were measured at positions where the fish were being observed.
Finneran, et al, 2007.
Assessing temporary threshold shift in a bottlenose dolphin (Tursiopstruncatus) using multiple simultaneous auditory evoked potentials.
The increased speed of the multiple ASSR technique also makes it a potentially useful approach for assessing frequency-dependent patterns of temporary hearing loss in animals, since hearing thresholds at multiple frequencies could be measured in a relatively short amount of time. To date, measurements of temporary hearing loss, or temporary threshold shift TTS, in marine mammals have used both behavioral.
McCauley, et al, 2005.
Marine petroleum exploration involves the repetitive use of high-energy noise sources, air-guns, that produce a short, sharp, low-frequency sound. Despite reports of behavioral responses of fishes and FIC marine mammals to such noise, it is not known whether exposure to air-guns has the potential to me' damage the ears of aquatic vertebrates. It is shown here that the ears of fish exposed to an operating 959mo air-gun sustained extensive damage to their sensory epithelia that was apparent as ablated hair cells. The damage was regionally severe, with no evidence of repair or replacement of damaged sensory cells up to 58 days after air-gun exposure.