Ocean Noise 2008 Science

Behavioral impacts clearly replaced strandings and deaths as the key issue for marine mammals encountering human noise. Several studies released during 2008 all suggest that whales of many species may stop or reduce their feeding when moderate to loud human sounds enter their habitat, and this particular impact is likely to become a central focus of future research and regulatory consideration.

The legal tussles over mid-frequency and low-frequency active sonars continued, and the Supreme Court decision does not put an end to the controversy. The Navy crossed an important threshold, completing full Environmental Impact Statements for their sonar training procedures for the first time; the lack of sufficient NEPA analysis was the root of most of the legal challenges. The plans they are putting forward to govern sonar training off most of the US coastline continue to rely on safety measures that Federal Courts have found wanting, though it appears that challenges to their proposals are more likely to focus on avoiding biologically important areas than increasing the safety zones that are designed to avoid injury. All parties seem to be accepting that gross injury is rare to the point of being difficult to use as a lever to shift the balance of interests with the Navy’s national security imperative, but NGOs, many field researchers, and agency staff are all looking more closely at the behavioral impacts that take place at much longer ranges (up to several or even tens of kilometers). The next round of Navy sonar conflicts will center on how willing the Navy is to consider these subtler impacts, and whether NMFS or the courts will impose broader territorial restrictions on sonar training to protect areas where whales may be more susceptible to repeated disruption by sonar transmissions.

Shipping noise is moving very quickly to the forefront of international concerns about rising ocean noise. This year the US, with strong German support, initiated a two-year process at the International Maritime Organization to come up with ship quieting recommendations. Also, the unusual sensitivity of harbor porpoises to boat noise has become clearer.

PDF

Acoustic Ecology Institute