August 23, 2010
NOAA’s Fisheries Service has issued regulations and a letter of authorization (LOA) to the U.S. Navy that require protective measures to minimize impacts to marine mammals while conducting training exercises around the Mariana Islands in the South Pacific.
The Navy requested an authorization under the Marine Mammal Protection Act because mid-frequency sound generated by tactical sonar and sound and pressure generated by detonating explosives may affect marine mammal behavior or cause temporary loss of hearing sensitivity.
NOAA’s Fisheries Service does not expect the exercises to result in serious injury or death to marine mammals and has required the Navy to use mitigation measures to avoid injury or death. Exposure to sonar in certain circumstances has been associated with the stranding of some marine mammals and, therefore, the authorization allows for a small number of incidental injuries or mortalities of marine mammals. NOAA’s Fisheries Service has determined these effects would have a negligible impact on the species or stocks involved.
Under the authorization the Navy is required to follow mitigation measures to minimize effects on marine mammals including:
NOAA’s Fisheries Service and the Navy have worked to develop a robust monitoring plan that includes extensive survey and photo-identification databases that will strengthen the marine mammal density and distribution data available in the Mariana Islands. Additionally, the Navy has developed (with input from NOAA’s Fisheries Service) an integrated comprehensive monitoring plan to prioritize monitoring goals and standardize data collection methods across all of their U.S. range complexes.
The authorization includes an adaptive management component that requires that the Navy and NOAA’s Fisheries Service 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.
The Navy has been conducting training exercises, including the use of mid-frequency sonar, in the Mariana Islands for more than 60 years. Exercises range from large, 10-day long joint multi-strike group exercises using multiple surface vessels, submarines and aircraft, to multi-hour exercises designed to target specific skills or weapons systems, such as missile tracking. Some exercises involve explosives.
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