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 what the Navy calls "a temporary loss of their hearing."
Mid-frequency sonar can emit continuous sound well above 235 decibels, an intensity roughly comparable to a rocket at blastoff. The sonar blasts travel across hundreds of miles of ocean to reveal objects, such as submarines, underwater.
NOAA's Fisheries Service, which issued the authorization says serious injury or death to marine mammals is not expected as a result of the exercises. But the agency acknowledges that exposure to sonar has been associated with the stranding of some marine mammals, and some injury or death could occur.
The Fisheries Service has determined that these effects would have "a negligible effect on the species or stocks involved."
Protective measures outlined by NOAA require the Navy to establish marine mammal safety zones around each vessel using sonar and shut down sonar operations if marine mammals are seen within designated safety zones.
The Navy must use exclusion zones to ensure that explosives are not detonated when animals are detected within a certain distance.
The Navy must implement a stranding response plan that includes a training shutdown provision in certain circumstances and a memorandum 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.
Humpback mother and calf in Hawaiian waters (Photo by Fotolen)
The regulations establish an area of extra caution in the Maui Basin because of its high density of humpback whales. The Hawaiian Islands National Marine Sanctuary covers the four island area of Maui; Penguin Bank; and extends off the north shore of Kauai, the north and south shores of Oahu, and the north Kona and Kohala coasts of the Big Island.
Hawaii is the only place in the United States where humpbacks breed, calve, and nurse their young. Approximately 4,000-5,000 whales migrate to the Hawaiian Islands each winter. Although the population of humpbacks is increasing, these whales remain endangered.
NOAA Fisheries Service said in a statement today that 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 loss of hearing."
But environmentalists disagree.
"The role of the National Marine Fisheries Service is to protect the health and welfare of marine mammals and they are abdicating their duty with this authorization," said Taryn Kiekow, marine mammal staff attorney with the Natural Resources Defense Council. The nonprofit organization has fought a series of legal battles against the Navy's use of sonar due to its adverse effects on whales and dolphins.
"They are recycling protections for sensitive marine mammal species and habitat near Hawaii that courts have repeatedly found inadequate," Keikow said.
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 Pacific Rim Training Exercises, to two- to three-day exercises to test the readiness of battle groups, known as Undersea Warfare Exercises, and shorter exercises that last less than a day.
NOAA's Fisheries Service and the Navy have developed a 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 better understand how marine mammals respond to various levels of sound and to assess the effectiveness of mitigation measures.
The implementation of this monitoring plan is included as a requirement of the regulations and the letter of authorization.
The letter of authorization, which is required for the Navy to legally conduct sonar activities, is 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.
Copyright Environment News Service (ENS) 2009. All rights reserved.