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Assessment of Deep Diving Whales Major Range Distribution within the Monterey Bay National Marine Sanctuary

Hall, D., and J. Kum (April 2001)

Technical Report, 13p.


Currently the U.S. Navy is consulting with the Director of the Office of National Marine Sanctuaries in order to deploy Surveillance Towed Array Sensor System Low Frequency Active Sonar (SURTASS LFA) within the Monterey Bay National Marine Sanctuary. The sonar system is a long-range, low frequency sonar that has both active and passive components. The purpose of the proposed action is to meet U.S. need for improved capability to detect foreign submarines at long range. The characteristics and operating features of the active component (LFA) are:

  • The source is a vertical line array of up to 18 source emitters suspended below the vessel.

  • LFA's transmitted beam is omnidirectional (360 degrees along a horizontal plane (nominal depth of the center of the array is 122m [400 ft]), with a narrow vertical beamwidth that can be steered above or below the horizontal axis.

  • The source frequency is between 100 and 500 Hz. A variety of signal types can be used including continuous wave (CW) and frequency-modulated signals.

It is possible that this deployment of acoustics will adversely affect Sanctuary resources. Operation of the SURTASS LFA system may constitute a violation of federal regulations at 15 CFR (922.132 (5)) which prohibit taking any marine mammal, sea turtle or seabird in or above the Sanctuary, except as permitted by regulations, under the Marine Mammal Protection Act, the Endangered Species Act, and the Migratory Bird Treaty Act. NOAA Fisheries (NMFS) will determine whether to grant the Department of Defense a small take exemption under the Marine Mammal Protection Act.

The FEIS for SURTASS LFA Appendix A states: "Sanctuary regulations require that military activities be carried out in a manner that avoids to the maximum extent practicable adverse impacts on Sanctuary resources and qualities. The Navy has determined that Alternative 1 of the Draft OEIS/EIS would meet this requirement".

Sanctuary regulations at 15 CFR 922.132 (c) except some Department of Defense activities from the above prohibitions, but only military activities specifically identified in the MBNMS Final Environmental Impact Statement/ Management Plan (FEIS/MP) published in June 1992. Sanctuary regulations are very clear in stating that the prohibitions in paragraphs (a) (2) through (9) do not apply to existing military activities carried out by the Department of Defense. SURTASS LFA was not identified as a pre-existing activity in the 1992 FEIS/MP, and would therefore not be eligible for exception from these prohibitions. However, new activities may be exempted after consultation between the Director and the Department of Defense.

We understand the intent of the Navy's proposal is to keep the sound source outside the limits of the United States Territorial Sea. This should reduce potential impacts to the migrating Gray whales during the winter and spring. However, the Monterey Bay National Marine Sanctuary has concerns regarding the variety and distributions of deep diving whales throughout our boundaries, in particular, offshore areas beyond the Territorial Sea during spring, summer, and fall.

Reviewed: April 11, 2024
Web Site Owner: National Ocean Service

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