Reduction of marine mammals exposure to harmful levels of sound

NOAANOAA Fisheries announced today final regulations requiring the United States Navy to implement protective measures during training and testing activities off the coasts of California and Hawaii and on the high seas of the Pacific Ocean to reduce the effects on marine mammals.

The Navy requested an authorization under the Marine Mammal Protection Act, because the sound generated by active sonar, the sound and pressure generated by detonating explosives, and other associated activities may affect the behavior of some marine mammals, cause a temporary loss of their hearing sensitivity or other injury.

NOAA Fisheries recently made a final determination that the effects of these Navy operations will have a negligible impact on the species or stocks involved. NOAA Fisheries is requiring that the Navy use mitigation measures designed to reduce impacts to marine mammals.

However, exposure to sonar in certain circumstances has been associated with the stranding of some marine mammals, and some injury or death may occur despite the best efforts of the Navy. Therefore, the authorization allows for a small number of incidental injuries or deaths to marine mammals from sonar, as well as vessel strikes and explosions.

Under the authorization, the Navy will have to follow mitigation measures to minimize effects on marine mammals, including:

  • establishing marine mammal mitigation zones around each vessel using sonar;
  • using Navy observers to shut down sonar operations if marine mammals are seen within designated mitigation zones;
  • using mitigation zones to ensure that explosives are not detonated when animals are detected within a certain distance;
  • implementing a stranding response plan that includes a training shutdown provision in certain circumstances, and allows for the Navy to contribute in-kind services to NOAA's Fisheries Service if the agency has to conduct a stranding response and investigation; and,
  • designating a "Humpback Whale Cautionary Area" to protect high concentrations of humpback whales around Hawaii during winter months.

These measures should minimize the potential for injury or death and significantly reduce the number of marine mammals exposed to harmful levels of sound.

Source: NOAA