NOAA Will Permit Limited Marine Mammal Deaths Due to Navy Sonar

Written by on January 12, 2009 in Policy & Ocean Law

Beaked Whale Beaches Itself After 2000 Sonar Exercise in The Bahamas

Beaked Whale Beaches Itself After 2000 Sonar Exercise in The Bahamas

The Navy requested authorization under the Marine Mammal Protection Act because the mid-frequency sound generated by tactical active 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.

NOAA’s Fisheries Service has issued regulations and a letter of authorization to the U.S. Navy that will condone a limited number of marine mammal deaths while conducting training exercises around the main Hawaiian Islands. The regulations require the Navy to implement measures designed to protect and minimize effects  to marine mammals.

NOAA’s Fisheries Service said it does not expect the exercises to result in serious injury or death to marine mammals, and is requiring the Navy to use mitigation measures intended to avoid injury or death.  NOAA said, however, that “in a small number of cases, exposure to sonar in certain circumstances has been associated with the stranding of some marine mammals, and some injury or death potentially could occur despite the best efforts of the Navy. Therefore, the regulations and the letter allow for incidental impacts on marine mammals, including injury or death of up to 10 animals of each of 11 species over the five years covered by the regulations.”

NOAA’s Fisheries Service said it has determined that these effects would have a negligible effect on the species or stocks involved.

If you’re wondering what Navy sonar sounds like, listen to this recording of a specific kind of towed, active sonar (SURTASS), and some whale songs that were recorded at the same time.  In the recording, the sonar is the monotone, low-frequency sound.

Sonar and Whales Together

NOAA said the Navy’s procedures will include: 

  • using Navy observers to shut down sonar operations if marine mammals are seen within designated safety zone;
  • using of exclusion 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 a memorndum of agreement to allow the Navy to contribute in-kind services to NOAA’s Fisheries Service if the agency has to conduct a stranding response and investigation;
  • establishing an area of extra caution in the Maui Basin because of its high density of humpback whales.

NOAA believes the 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 loss of hearing.

NOAA said its Fisheries Service and the Navy worked “to develop a robust monitoring plan to use independent, experienced aerial and vessel-based marine mammal observers (as well as Navy watch standers), passive acoustic monitoring, and tagging to help better understand how marine mammals respond to various levels of sound and to assess the effectiveness of mitigation measures.”  NOAA added that the implementation of this monitoring plan is included as a requirement of the regulations and the letter.

The Navy has been conducting training exercises, including the use of mid-frequency sonar, in the Hawaiian Islands for more than 40 years. Exercises range from large multi-national, month-long training exercises using multiple submarines, ships, and aircraft conducted every other year, known as Rim of Pacific Training Exercises (RIMPAC), to two- to three-day exercises to test the readiness of battle groups, known as Undersea Warfare Exercises or USWEXs, and shorter exercises that last less than a day. In addition, some exercises involve the use of explosives.

This regulation, in effect for five years, governs the incidental take of marine mammals during the Navy’s training activities, and includes required mitigation and monitoring measures. The letters of authorization, which are required for the Navy to legally conduct their activities, are issued annually, provided the Navy abides by the terms and conditions of the letter, submits the required annual reports, and shows their activities do not result in more numerous effects or more severe harm to marine mammals than were originally analyzed or authorized.

In a related, but separate issue, the Navy and a coalition of environmental groups recently settled more than three years of litigation over the Navy’s failure to perform environmental impact assessments related to its sonar training exercises.  You can read the Navy’s press release on the settlement here, and the National Resources Defense Council press release here.

Copyright ©  2009 by Marine Science Today, a publication of OceanLines LLC

About the Author

About the Author: Tom Tripp is the owner of OceanLines Ltd., the publisher of OceanLines and founder and Editor Emeritus of Marine Science Today. He is an award-winning marine journalist, science and aviation writer and long-time public communications specialist. His PR career and much of his writing stems from the fact that he loves to explain stuff. It all began when he and his brother Mark threw all of Mom's tomatoes at the back wall of the house. . . .


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