216.184—Mitigation.
The activity identified in § 216.180(a) must be conducted in a manner that minimizes, to the greatest extent practicable, adverse impacts on marine mammals and their habitats. When conducting operations identified in § 216.180, the mitigation measures described in this section and in any Letter of Authorization issued under §§ 216.106 and 216.188 must be implemented.
(a)
Through monitoring described under § 216.185, the Holder of a Letter of Authorization must act to ensure, to the greatest extent practicable, that no marine mammal is subjected to a sound pressure level of 180 dB or greater.
(b)
If a marine mammal is detected within or about to enter the mitigation zone (the area subjected to sound pressure levels of 180 dB or greater plus the 1 km (0.54 nm) buffer zone extending beyond the 180-dB zone), SURTASS LFA sonar transmissions will be immediately delayed or suspended. Transmissions will not resume earlier than 15 minutes after:
(2)
There is no further detection of any marine mammal within the mitigation and buffer zones as determined by the visual and/or passive or active acoustic monitoring described in § 216.185.
(c)
The high-frequency marine mammal monitoring sonar (HF/M3) described in § 216.185 will be ramped-up slowly to operating levels over a period of no less than 5 minutes:
(2)
Prior to any SURTASS LFA sonar calibrations or testings that are not part of regular SURTASS LFA sonar transmissions described in paragraph (c)(1) of this section; and
(d)
The HF/M3 sound pressure level will not be increased once a marine mammal is detected; ramp-up may resume once marine mammals are no longer detected.
(1)
the SURTASS LFA sonar sound field exceeds 180 dB (re 1 microPa(rms)) at a distance less than 12 nautical miles (nm) (22 kilometers (km)) from any coastline, including offshore islands;
(2)
the SURTASS LFA sonar sound field exceeds 180 db (re 1 microPa(rms)) at a distance of 1 km (0.5 nm) seaward of the outer perimeter of any offshore biologically important area designated in 216.184(f) during the biologically important period specified.
(f)
The following areas have been designated by NMFS as Offshore Biologically Important Areas (OBIAs) for marine mammals (by season if appropriate):
| Name of area | Location of area | Months of importance |
|---|---|---|
| (1) 200-m isobath North American East Coast | From 28° N. to 50° N., west of 40° W | Year-round. |
| (2) Antarctic Convergence Zone | 30° E. to 80° E. to 45°; 80° E. to 150° E. to 55°; S. 150° E. to 50° W. to 60° S.; 50° W. to 30° E. to 50° S | October 1-March 31. |
| (3) Costa Rica Dome | Centered at 9° N. and 88° W | Year-round. |
| (4) Hawaiian Islands Humpback Whale National Marine Sanctuary-Penguin Bank | Centered at 21° N. and 157° 30' W | November 1 through May 1. |
| (5) Cordell Bank National Marine Sanctuary | Boundaries in accordance with 15 CFR 922.110 | Year-round. |
| (6) Gulf of the Farallones National Marine Sanctuary | Boundaries in accordance with 15 CFR 922.80 | Year-round. |
| (7) Monterey Bay National Marine Sanctuary | Boundaries in accordance with 15 CFR 922.30 | Year-round. |
| (8) Olympic Coast National Marine Sanctuary | Boundaries within 23 nm of the coast from 47°07′ N. to 48°30′ N. latitude | December January, March and May. |
| (9) Flower Garden Banks National Marine Sanctuary | Boundaries in accordance with 15 CFR 922.120 | Year-round. |
| (10) The Gully | 44°13′ N., 59°06′ W. to 43°47′ N.; 58°35′ W. to 43°35′ N.; 58°35′ W. to 43°35′ N.; 59°08′ W. to 44°06′ N.; 59°20′ W | Year-round. |