Behavioural and physiological effects of anthropogenic sound on cetaceans

R. Lung \ Oceans First, Issue 1, 2014, pgs. 12-19.

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Abstract:

Studies show increasingly negative effects associated with anthropogenic sound and human disturbance. These negative effects are both behavioural and physiological. The chronic activation of the short-term stress response as a result of increased ship noise potentially has detrimental effects regarding growth, reproduction, immune function, and digestion. Methods to acquire data involving behaviour are mainly observational. To monitor acoustic behaviour, hydrophones are used. The behaviour of cetacean species is altered in the presence of human disturbances such as marine construction, sonar, and ship noise. Their vocalizations are also affected; differing in length, overall presence, and frequency. Mass strandings have occurred as a result of active naval sonar exposure. Naval sonar administers frequencies similar to those of beaked whales, often resulting in acoustic masking. To examine sustained injuries, post-mortem internal examinations are conducted. The sonar signals can have fatal effects, including hemorrhage in multiple organs, gas and fat embolism, and bubble lesions formed as a result of the supersaturation of nitrogen gas within tissues. Future research will enable the determining of more long term effects in relation to anthropogenic sound effects.