Sound in the oceans and its effect on marine mammals

Abstract

Editor's note: The Marine Mammals Protection Act of 1972 is up for renewal by the U.S. Congress this year. Because amendments to this law could dramatically impact the use of air guns in U.S. waters, Jack Caldwell has prepared this summary of issues likely to be focal points during congressional hearings on this matter. John Richardson (LGL, Ltd.) and Roger Gentry (NMFS) contributed many helpful comments to this summary. In recent years, attention has increasingly focused on dramatically rising noise levels in the world's oceans and their possible effects on marine life (particularly marine mammals). The United Kingdom, Australia, and the United States are studying the effects of seismic survey noise on mammals and are requiring mitigation to help protect marine mammals from possible negative effects. In the United States, the groups most actively involved (and most aware of developments taking place) with regard to the overall noise issue include U.S. federal and state regulatory bodies such as the Minerals Management Service (MMS), the National Marine Fisheries Service (NMFS), and the California Coastal Commission (CCC); biologists (particularly those interested in marine mammals); acousticians (especially those who study sound propagation in the oceans); groups that use sound in the oceans for research (U.S. Navy, U.S. Geological Survey, and numerous universities); and environmental groups such as the Natural Resources Defense Council. Less involved—at least until this point—is the oil industry, and perhaps less still is the shipping industry. The National Research Council conducted a study on this issue from 1992 to 1994 and concluded that the state of knowledge concerning the effects of noise on marine mammals is woefully lacking. Research is being conducted to improve the state of knowledge, but definitive work remains scarce. Key questions include: