Environmental impact assessment guidelines for offshore petroleum exploration seismic surveys

Abstract

The ocean environment is filled with natural sound, but the last century has introduced many anthropogenic activities that have increased the levels of noise. Research on the impact of anthropogenic noise on marine fauna is now extensive. Levels of threat are well defined. Mitigation and monitoring guidelines exist in many parts of the world; especially for offshore petroleum exploration. In many jurisdictions, these guidelines rely on environmental impact assessments (EIAs) consideration by decision-makers, yet few jurisdictions stipulate what such assessments should contain. Sound propagation in the marine environment is complex, yet robust and defensible modelling is rarely conducted. Many impact assessments are inadequately checked. This stands in contrast to the equivalent process for land-based assessments. We argue that defensible EIAs should include modelling of the proposed noise impact in the region and under the conditions of planned activity. We articulate why clear guidelines about the content of EIAs are needed and propose a template for offshore petroleum exploration assessment.