Research Document - 2004/125

Potential Effect of Seismic Surveys on Fish Eggs, Larvae and Zooplankton

Payne, J.F.

Abstract

Data are generally insufficient to provide informed opinion on the size of injury zones for eggs and larvae of fish and shellfish (or on other planktonic organisms) stemming from seismic activities. With respect to fisheries, it follows that this knowledge gap will have to be considered before questions of potential impacts on populations can be addressed with confidence. It would also be premature at this time to adopt specific reference levels. However it is important to point out that the primary concern would be in relation to the potential for impacts at the stock or sub-stock level such as in a confined bay or similar type of risk zone. A few representative studies on distance-effect relationships would greatly aid understanding in this area with the potential for effects stemming from cumulative energy as well as peak energy being considered, including under conditions of 3-D surveys. Such studies are needed if only for assurance. In addition to injurious effects of a more or less physical nature on larvae or other planktonic forms, the question of subtle effects such as those which may be connected with behavioral functions of communication, movement in the water column or larval settlement can also be asked (with the understanding that like behavioural functions could also be influenced by injurious effects of a physical nature). Although not discussed here, it can also be asked whether other sources of sound such as that associated with select ship traffic lanes may often present equal or greater concerns with respect to some effects, such as those which may be implicated in affecting behaviour.

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