Marine Sound Pollution: Does It Merit Concern?

Abstract

The possible effects on marine mammals and other marine organisms of sound from human (anthropogenic) sources have become subjects of increasing concern and controversy. In the late 1970s and 1980s, the sources of principal concern were seismic profiling, drilling, and related activities associated with offshore oil and gas development. In the last decade, much of the focus has shifted to activities conducted or supported by the U.S. Navy, most notably the Acoustic Thermometry of Ocean Climate Program, ship-shock tests, development and proposed use of low frequency active sonar to detect new classes of quiet submarines, and the stranding of beaked whales and other cetaceans in the Bahamas in March 2000 coincident with antisubmarine exercises involving use of mid-frequency tactical sonars. There has been substantial controversy concerning the possible impacts of these activities, and a number of law suits seeking to stop or restrict them. The Navy believes that the concerns are unwarranted and that the law suits have impeded its ability to meet its national defense responsibilities. Congress agreed and in the National Defense Authorization Act for Fiscal Year 2004 (Public Law 108-87) made two substantial changes to the Marine Mammal Protection Act (MMPA): (1) it authorized the Secretary of Defense to exempt military readiness activities from the provisions of the MMPA governing the incidental taking of marine mammals; and (2) it added to the Act separate definitions of harassment to apply to such activities. These and other proposed changes to the MMPA could undermine the unique, precautionary or risk-averse philosophy of the Act. An alternative, two-step approach, advocated in this paper, would be to (a) revise the definition of harassment to clearly differentiate types and levels of behavioral disturbance likely to have, and not to have, biologically significant effects; and (b) add a general authorization for all incidental taking expected to have biologically insignificant effects, similar to the general authorization for marine mammal research expected to have biologically insignificant effects added to the MMPA in 1994.