A close encounter between a blue whale and a cargo ship in the Santa Barbra Channel.
(Photo courtesy of NOAA)
important habitats for numerous marine mammals, including several of the large whales. To address this issue, Okeanos -- Foundation for the Sea held an International Workshop on Shipping Noise and Marine Mammals in Hamburg, Germany, in April 2008. This meeting convened a diverse group of stakeholders from around the world with expertise in the areas of underwater acoustics, naval architecture, marine engineering, shipbuilding, marine mammal bioacoustics, maritime operations (i.e., ship owners and operators), and noise control, as well as in international maritime and environmental law and policy. Participants noted that, unlike chemical pollution, noise does not persist in the environment. This means that if a source of noise is reduced, the amount of noise energy in the water is immediately lowered (measurably or not, depending on other noise in the area). Also, unlike military sonar or seismic surveys, none of the incidental noise introduced into the marine environ24 MTR
ment by commercial shipping serves an intended purpose. This means that it could theoretically be eliminated without affecting shipping activities. Under these favorable circumstances, participants decided that the amount of noise introduced into the marine environment from shipping could and should be minimized as much as possible to reduce or eliminate the impacts of noise on whales and other marine mammals. To achieve this goal the workshop participants called for initial global action that is intended to reduce the contributions of shipping to ambient noise energy in the 10300 Hz band by (on average) 3 dB in 10 years and by 10 dB in 30 years relative to current levels. It is, of course, expected that some areas will require and experience greater changes than others as a result of quieting commercial vessel operations. The workshop participants concluded that this global goal would be best accomplished through technological and/or operational measures designed to reduce the noise
June 2008
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