Seismic surveys and marine wildlife: Impacts, the lack thereof, and thoughts on managing both

Abstract

Sufficient scientific data exist to conclude that seismic airguns used in geophysical exploration have a low probability of direct harm to most marine life, except at close range where physical injury is a real danger. Further, airguns in some conditions do not appear to disturb animals; however, in other conditions, they result in moderate to extreme behavioral responses and/or acoustic masking over large areas. Additionally, recent studies have reported the presence of seismic survey sound energy over ranges of ~4000 km. While the potential for effects have not even been investigated at such ranges, the presence of the signals must be taken into account when evaluating overall potential for impacts. Mitigation measures have historically focused on reducing immediate harm, but systematically measuring and understanding the full potential for impacts is an important aspect of any responsible development program. The European Union has recognized ocean noise as a pollutant and as an indicator of environmental quality under its Marine Strategy Framework Directive. Given this and the international and transboundary nature of noise from marine seismic surveys, their ubiquity, the presence of numerous other sources of ocean noise, and that incorporating acoustic disturbance into an understanding of population level consequences is progressing, a responsible path forward should focus on the creation of legally binding international commitments and standards for the management and minimization of noise.