Research Document - 2006/092

Effects of Seismic Energy on Fish: A Literature Review

By T. Worcester

Abstract

The potential impacts of geophysical (seismic) surveys on adult and juvenile fish in Canadian waters are investigated through a literature review of laboratory and in situ studies on the behavioural, physical and biochemical responses of fish to sound, focusing primarily on impacts of airgun sources. Based on the limited number of studies that have been conducted to date, there is considered to be a high probability that some fish within the general vicinity (i.e. hundreds of meters) of a seismic survey operation will exhibit startle responses, changes in swimming speed or direction, and changes in vertical distribution, with recovery likely within minutes to hours after exposure. There is a lower but still reasonable probability that seismic surveys will influence the horizontal distribution and catchability of some fish under certain conditions, such as during migration of pelagic fish. If horizontal dispersion does occur, impacts are more likely to be observed over greater distances (kilometers) and for a longer duration (days). Seismic surveys are considered unlikely to result in immediate mortality of fish; however, sublethal physical damage and physiological impairments may occur within close proximity to an airgun source and could potentially result in delayed mortality or chronic effects. However, additional research is required to assess the intensity of sound levels or typical ranges from a known seismic source required to produce these types of effects. The potential for seismic surveys to disrupt communication and other sound-dependant activities of fish is essentially unknown, as is the long-term ecological significance of the impacts described above.

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