November 9, 2010
NOAA’s Fisheries Service has issued regulations and a letter of authorization to the U.S. Navy that includes measures to protect marine mammals while conducting training exercises off the coasts of Washington, Oregon, and northern California.
The regulations and letter require the Navy to implement protective measures during training to minimize impacts to marine mammals.
The Navy requested an authorization under the Marine Mammal Protection Act, because the mid-frequency sound generated by tactical sonar, and the sound and pressure generated by detonating explosives, may affect the behavior of some marine mammals, or cause a temporary loss of their hearing sensitivity.
NOAA’s Fisheries Service does not expect the exercises to result in serious injury or death to marine mammals. NOAA is requiring the Navy to use mitigation measures to avoid injury or death. In certain circumstances exposure to sonar has been associated with the stranding of some marine mammals. Therefore, authorizations for Navy training exercises at other locations where those circumstances may exist have included allowances for a small number of incidental injuries or mortalities of marine mammals. However, due to the short duration and less intense nature of the sonar exercises in the northwest training range, mortality is not anticipated or authorized.
Under the authorization, the Navy is required to follow mitigation measures to minimize effects on marine mammals, including:
These measures should minimize the potential for injury or death, and significantly reduce the number of marine mammals exposed to levels of sound likely to cause temporary or permanent loss of hearing sensitivity. Additionally, the authorization includes an adaptive management component that requires that the Navy and NOAA’s Fisheries Service to meet yearly to discuss new science, Navy research and development, and Navy monitoring results, to determine if modifications to mitigation or monitoring measures are appropriate.
NOAA’s Fisheries Service and the Navy have worked to develop a monitoring plan that includes passive acoustic monitoring and marine mammal tagging that will augment the marine mammal abundance and distribution data available in the Northwest. Additionally, the Navy has developed (with input from NOAA’s Fisheries Service) an integrated comprehensive monitoring plan to better prioritize monitoring goals and standardize data collection methods across all of their U.S. range complexes.
The Navy has been conducting training exercises, including the use of mid-frequency sonar, in the northwest training range for more than 60 years. Training in this area consist primarily of 1½-hour exercises by one surface vessel, using sonar while the vessel is in transit from one location to another. The total annual sonar use in this area is substantively less than planned in other Navy training ranges. Some exercises involve explosives.
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