50 CFR 218.74 - Mitigation requirements.

Regulations last checked for updates: Feb 06, 2026

Title 50 - Wildlife and Fisheries last revised: Jan 22, 2026

View all text of Subpart H [§ 218.70 - § 218.79]

§ 218.74 - Mitigation requirements.

(a) When conducting the activities identified in § 218.70(c), the mitigation measures contained in this section and any LOA issued under this subpart must be implemented by Action Proponent personnel or contractors who are trained according to the requirements in the LOA. If Action Proponent contractors are serving on behalf of Action Proponent personnel, Action Proponent contractors must follow the mitigation applicable to Action Proponent personnel. These mitigation measures include, but are not limited to:

(1) Activity-based mitigation. Activity-based mitigation is mitigation that the Action Proponents must implement whenever and wherever an applicable military readiness activity takes place within the HCTT Study Area. The Action Proponents must implement the mitigation described in paragraphs (a)(1)(i) through (xxii) of this section, except as provided in paragraph (a)(1)(xxiii) of this section.

(i) Active acoustic sources with power down and shut down capabilities. For active acoustic sources with power down and shutdown capabilities (low-frequency active sonar ≥200 decibels (dB), mid-frequency active sonar sources that are hull mounted on a surface ship (including surfaced submarines), and broadband and other active acoustic sources >200 dB):

(A) Mitigation zones and requirements. During use of active acoustic sources with power down and shutdown capabilities, the following mitigation zone requirements apply:

(1) Within 1,000 yards (yd) (914.4 meters (m)) from a marine mammal, Action Proponent personnel must power down active acoustic sources by 6 dB total.

(2) Within 500 yd (457.2 m) from a marine mammal, Action Proponent personnel must power down active acoustic sources by an additional 4 dB (10 dB total).

(3) Within 200 yd (182.9 m) from a marine mammal, Action Proponent personnel must shut down active acoustic sources.

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in or on one of the following: aircraft; pierside, moored, or anchored vessel; underway vessel with space/crew restrictions (including small boats); or underway vessel already participating in the event that is escorting (and has positive control over sources used, deployed, or towed by) an unmanned platform.

(2) Two Lookouts on an underway vessel without space or crew restrictions.

(3) Lookouts must use information from passive acoustic detections to inform visual observations when passive acoustic devices are already being used in the event.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of using active acoustic sources (e.g., while maneuvering on station).

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals during use of active acoustic sources.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing or powering up active sonar transmission). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft).

(ii) Active acoustic sources with shut down capabilities only (no power down capability). For active acoustic sources with shut down capabilities only (no power down capability) (low-frequency active sonar <200 dB, mid-frequency active sonar sources that are not hull mounted on a surface ship (e.g., dipping sonar, towed arrays), high-frequency active sonar, air guns, and broadband and other active acoustic sources <200 dB):

(A) Mitigation zones and requirements. During use of active acoustic sources with shut down capabilities only, the following mitigation zone requirements apply:

(1) At 200 yd (182.9 m) from a marine mammal, Action Proponent personnel must shut down active acoustic sources.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(2) Two Lookouts on an underway vessel without space or crew restrictions.

(3) Lookouts must use information from passive acoustic detections to inform visual observations when passive acoustic devices are already being used in the event.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals during use of active acoustic sources.

(iii) Pile driving and extraction. For pile driving and extraction:

(A) Mitigation zones and requirements. During vibratory and impact pile driving and extraction, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease pile driving or extraction if a marine mammal is sighted within 5 yd (4.6 m) of a pile being driven or extracted.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in or on one of the following: shore, pier, or small boat.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation for 15 minutes prior to the initial start of pile driving or pile extraction.

(2) Action proponent personnel must use soft start standard operating procedures when impact pile driving. Soft start requires the Action Proponent to conduct three sets of strikes (three strikes per set) at reduced hammer energy with a 30-second waiting period between each set. A soft start must be implemented at the start of each day's impact pile driving and at any time following cessation of impact pile driving for a period of 30 minutes or longer.

(3) Action Proponent personnel must observe the mitigation zone for marine mammals during pile driving or extraction.

(iv) Weapons firing noise. For weapons firing noise:

(A) Mitigation zones and requirements. During explosive and non-explosive large-caliber (57 millimeter (mm) and larger) gunnery firing noise (surface-to-surface and surface-to-air), the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease weapons firing if a marine mammal is sighted within 30 degrees on either side of the firing line out to 70 yd (64 m) from the gun muzzle (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a vessel.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of large-caliber gun firing (e.g., during target deployment).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals during large-caliber gun firing.

(v) Explosive bombs. For explosive bombs:

(A) Mitigation zones and requirements. During the use of explosive bombs of any net explosive weight (NEW), the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of explosive bombs if a marine mammal is sighted within 2,500 yd (2,286 m) from the intended target.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of bomb delivery (e.g., when arriving on station).

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals during bomb delivery. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(3) After the event, when practical, Action Proponent personnel must observe the detonation vicinity for injured or dead marine mammals. If any injured or dead marine mammals are observed, Action Proponent personnel must follow established incident reporting procedures (the Notification and Reporting Plan is available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities).

(vi) Explosive gunnery. For explosive gunnery:

(A) Mitigation zones and requirements. During air-to-surface medium-caliber (larger than 50 caliber and less than 57 mm), surface-to-surface medium-caliber, and surface-to-surface large-caliber explosive gunnery, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of air-to-surface medium-caliber ordnance if a marine mammal is sighted within 200 yd (182.9 m) of the intended impact location.

(2) Action Proponent personnel must cease use of surface-to-surface medium-caliber ordnance if a marine mammal is sighted within 600 yd (548.6 m) of the intended impact location.

(3) Action Proponent personnel must cease use of surface-to-surface large-caliber ordnance if a marine mammal is sighted within 1,000 yd (914.4 m) of the intended impact location.

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a vessel or in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of gun firing (e.g., while maneuvering on station).

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals during gunnery fire. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing air-to-surface medium-caliber, surface-to-surface medium-caliber, surface-to-surface large-caliber explosive gunnery). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).

(vii) Explosive underwater demolition multiple charge—mat weave and obstacle loading. For explosive underwater demolition multiple charge—mat weave and obstacle loading:

(A) Mitigation zones and requirements. During the use of explosive underwater demolition multiple charge—mat weave and obstacle loading of any NEW, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease explosive underwater demolition multiple charge—mat weave and obstacle loading if a marine mammal is sighted within 700 yd (640 m) of the detonation site.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) Two Lookouts, one on a small boat and one on shore from an elevated platform.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) The Lookout positioned on a small boat must observe the mitigation zone for marine mammals and floating vegetation for 30 minutes prior to the first detonation.

(2) The Lookout positioned on shore must use binoculars to observe for marine mammals for 10 minutes prior to the first detonation.

(3) Action Proponent personnel must observe the mitigation zone for marine mammals during detonations. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(4) After the event, when practical, Action Proponent personnel must observe the detonation vicinity for injured or dead marine mammals. If any injured or dead marine mammals are observed, Action Proponent personnel must follow established incident reporting procedures.

(viii) Explosive mine countermeasure and neutralization (no divers). For explosive mine countermeasure and neutralization (no divers):

(A) Mitigation zones and requirements. During explosive mine countermeasure and neutralization using 0.1-5 pound (lb) (0.05-2.3 kilogram (kg)) NEW and >5 lb (2.3 kg) NEW, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of 0.1-5 lb (0.05-2.3 kg) NEW if a marine mammal is sighted within 600 yd (548.6 m) from the detonation site.

(2) Action Proponent personnel must cease use of >5 lb (2.3 kg) NEW if a marine mammal is sighted within 2,100 yd (1,920.2 m) from the detonation site.

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a vessel or in an aircraft during 0.1-5 lb (0.05-2.3 kg) NEW use.

(2) Two Lookouts, one on a small boat and one in an aircraft during >5 lb (2.3 kg) NEW use.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of detonations (e.g., while maneuvering on station; typically, 10 or 30 minutes depending on fuel constraints).

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals, concentrations of seabirds, and individual foraging seabirds (in the water and not on shore) during detonations or fuse initiation. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(3) After the event, when practical, Action Proponent personnel must observe the detonation vicinity for 10 or 30 minutes (depending on fuel constraints) for injured or dead marine mammals. If any injured or dead marine mammals are observed, Action Proponent personnel must follow established incident reporting procedures.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing explosive mine countermeasure and neutralization using 0.1-5 pound (lb) (0.05-2.3 kilogram (kg)) NEW and >5 lb (2.3 kg) NEW). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft).

(ix) Explosive mine neutralization (with divers). For explosive mine neutralization (with divers):

(A) Mitigation zones and requirements. During explosive mine neutralization (with divers) using 0.1-20 lb (0.05-9.1 kg) NEW (positive control), 0.1-29 lb (0.05-13.2 kg) NEW (time-delay), and >20-60 lb (9.1-27.2 kg) NEW (positive control), the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of 0.1-20 lb (0.05-9.1 kg) NEW (positive control) if a marine mammal is sighted within 500 yd (457.2 m) of the detonation site (cease fire).

(2) Action Proponent personnel must cease use of 0.1-29 lb (0.05-13.2 kg) NEW (time-delay) and >20-60 lb (9.1-27.2 kg) NEW (positive control) if a marine mammal is sighted within 1,000 yd (914.4 m) of the detonation site (cease fire).

(B) Lookout requirements. The following Lookout requirements apply:

(1) Lookouts in two small boats (one Lookout per boat), or one small boat and one rotary-wing aircraft (with one Lookout each), and one Lookout on shore for shallow-water events during use of 0.1-20 lb (0.05-9.1 kg) NEW (positive control).

(2) Four Lookouts in two small boats (two Lookouts per boat) and one additional Lookout in an aircraft if used in the event during use of 0.1-29 lb (0.05-13.2 kg) NEW (time-delay) and >20-60 lb (9.1-27.2 kg) NEW (positive control).

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Time-delay devices must be set not to exceed 10 minutes.

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of detonations or fuse initiation for positive control events (e.g., while maneuvering on station) or for 30 minutes prior for time-delay events.

(3) Action Proponent personnel must observe the applicable mitigation zone for marine mammals, concentrations of seabirds, and individual foraging seabirds (in the water and not on shore) during detonations or fuse initiation. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(4) When practical based on mission, safety, and environmental conditions: (i) Boats must observe from the mitigation zone radius mid-point.

(ii) When two boats are used, boats must observe from opposite sides of the mine location.

(iii) Platforms must travel a circular pattern around the mine location.

(iv) Boats must have one Lookout observe inward toward the mine location and one Lookout observe outward toward the mitigation zone perimeter.

(v) Divers must be part of the Lookout Team.

(5) After the event, when practical, Action Proponent personnel must observe the detonation vicinity for 30 minutes for injured or dead marine mammals. If any injured or dead marine mammals are observed, Action Proponent personnel must follow established incident reporting procedures.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing explosive mine neutralization (with divers) using 0.1-20 lb (0.05-9.1 kg) NEW (positive control), 0.1-29 lb (0.05-13.2 kg) NEW (time-delay), and >20-60 lb (9.1-27.2 kg) NEW (positive control)). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft).

(x) Explosive missiles and rockets. For explosive missiles and rockets:

(A) Mitigation zones and requirements. During the use of explosive missiles and rockets using 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface) and >20-500 lb (9.1-226.8 kg) NEW (air-to-surface), the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface) if a marine mammal is sighted within 900 yd (823 m) of the intended impact location (cease fire).

(2) Action Proponent personnel must cease use of >20-500 lb (9.1-226.8 kg) NEW (air-to-surface) if a marine mammal is sighted within 2,000 yd (1,828.8 m) of the intended impact location (cease fire).

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the applicable mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of missile or rocket delivery (e.g., during a fly-over of the mitigation zone).

(2) Action Proponent personnel must observe the applicable mitigation zone for marine mammals during missile or rocket delivery. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing use of explosive missiles and rockets using 0.6-20 lb (0.3-9.1 kg) NEW (air-to-surface) and >20-500 lb (9.1-226.8 kg) NEW (air-to-surface)). The wait period for this activity is 30 minutes for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).

(xi) Explosive sonobuoys and research-based sub-surface explosives. For explosive sonobuoys and research-based sub-surface explosives:

(A) Mitigation zones and requirements. During the use of explosive sonobuoys and research-based sub-surface explosives using any NEW of sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW for other types of sub-surface explosives used in research applications, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of any NEW of sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW for other types of sub-surface explosives used in research applications if a marine mammal is sighted within 600 yd (548.6 m) of the device or detonation sites (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a small boat or in an aircraft.

(2) Conduct passive acoustic monitoring for marine mammals; use information from detections to assist visual observations.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of detonations (e.g., during sonobuoy deployment, which typically lasts 20-30 minutes).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals during detonations. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing use of explosive sonobuoys and research-based sub-surface explosives using any NEW of sonobuoys and 0.1-5 lb (0.05-2.3 kg) NEW for other types of sub-surface explosives used in research applications). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft).

(xii) Explosive torpedoes. For explosive torpedoes:

(A) Mitigation zones and requirements. During the use of explosive torpedoes of any NEW, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of explosive torpedoes of any NEW if a marine mammal is sighted within 2,100 yd (1,920.2 m) of the intended impact location.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in an aircraft.

(2) Conduct passive acoustic monitoring for marine mammals; use information from detections to assist visual observations.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals, floating vegetation, and jellyfish aggregations immediately prior to the initial start of detonations (e.g., during target deployment).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals and jellyfish aggregations during torpedo launches. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing use of explosive torpedoes of any NEW). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).

(xiii) Ship shock trials. For ship shock trials:

(A) Mitigation zones and requirements. During ship shock trials using any NEW, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease ship shock trials of any NEW if a marine mammal is sighted within 3.5 nmi (6.5 km) of the target ship hull (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) On the day of the event, 10 observers (Lookouts and third-party observers combined), spread between aircraft or multiple vessels as specified in the event-specific mitigation plan.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must develop a detailed, event-specific monitoring and mitigation plan in the year prior to the event and provide it to NMFS for review.

(2) Beginning at first light on days of detonation, until the moment of detonation (as allowed by safety measures) Action Proponent personnel must observe the mitigation zone for marine mammals, floating vegetation, jellyfish aggregations, large schools of fish, and flocks of seabirds.

(3) If any injured or dead marine mammals are observed after an individual detonation, Action Proponent personnel must follow established incident reporting procedures and halt any remaining detonations until Action Proponent personnel consults with NMFS and review or adapt the event-specific mitigation plan, if necessary.

(4) During the 2 days following the event (minimum) and up to 7 days following the event (maximum), and as specified in the event-specific mitigation plan, Action Proponent personnel must observe the detonation vicinity for injured or dead marine mammals.

(xiv) Sinking exercises. For Sinking Exercises (SINKEX):

(A) Mitigation zones and requirements. During SINKEX using any NEW, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease SINKEX of any NEW if a marine mammal is sighted within 2.5 nmi (4.6 km) of the target ship hull (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) Two Lookouts, one on a vessel and one in an aircraft.

(2) Conduct passive acoustic monitoring for marine mammals; use information from detections to assist visual observations.

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) During aerial observations for 90 minutes prior to the initial start of weapon firing, Action Proponent personnel must observe the mitigation zone for marine mammals, floating vegetation, and jellyfish aggregations.

(2) From the vessel during weapon firing, and from the aircraft and vessel immediately after planned or unplanned breaks in weapon firing of more than 2 hours, Action Proponent personnel must observe the mitigation zone for marine mammals. If a marine mammal is visibly injured or killed as a result of detonation, use of explosives in the event must be suspended immediately.

(3) Action Proponent personnel must observe the detonation vicinity for injured or dead marine mammals for 2 hours after sinking the vessel or until sunset, whichever comes first. If any injured or dead marine mammals are observed, Action Proponent personnel must follow established incident reporting procedures.

(xv) Non-explosive aerial-deployed mines and bombs. For non-explosive aerial-deployed mines and bombs:

(A) Mitigation zones and requirements. During the use of non-explosive aerial-deployed mines and non-explosive bombs, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease using non-explosive aerial-deployed mines and non-explosive bombs if a marine mammal is sighted within 1,000 yd (914.4 m) of the intended target (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation immediately prior to the initial start of mine or bomb delivery (e.g., when arriving on station).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals during mine or bomb delivery.

(xvi) Non-explosive gunnery. For non-explosive gunnery:

(A) Mitigation zones and requirements. During the use of non-explosive surface-to-surface large-caliber ordnance, non-explosive surface-to-surface and air-to-surface medium-caliber ordnance, and non-explosive surface-to-surface and air-to-surface small-caliber ordnance, the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease non-explosive surface-to-surface large-caliber ordnance, non-explosive surface-to-surface and air-to-surface medium-caliber ordnance, and non-explosive surface-to-surface and air-to-surface small-caliber ordnance use if a marine mammal is sighted within 200 yd (182.9 m) of the intended impact location (cease fire).

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a vessel or in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation immediately prior to the start of gun firing (e.g., while maneuvering on station).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals during gunnery firing.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing use of non-explosive surface-to-surface large-caliber ordnance, non-explosive surface-to-surface and air-to-surface medium-caliber ordnance, and non-explosive surface-to-surface and air-to-surface small-caliber ordnance). The wait period for this activity is 30 minutes for activities conducted from vessels and for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).

(xvii) Non-explosive missiles and rockets. For non-explosive missiles and rockets:

(A) Mitigation zones and requirements. During the use of non-explosive missiles and rockets (air-to-surface), the following mitigation zone requirements apply:

(1) Action Proponent personnel must cease use of non-explosive missile and rocket (air-to-surface) if a marine mammal is sighted within 900 yd (823 m) of the intended impact location.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout in an aircraft.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals and floating vegetation immediately prior to the start of missile or rocket delivery (e.g., during a fly-over of the mitigation zone).

(2) Action Proponent personnel must observe the mitigation zone for marine mammals during missile or rocket delivery.

(D) Commencement or recommencement conditions. Action Proponent personnel must ensure one of the commencement or recommencement conditions in paragraph (a)(1)(xxii) of this section is met prior to the initial start of the activity (by delaying the start) or during the activity (by not recommencing use of non-explosive missiles and rockets (air-to-surface)). The wait period for this activity is 30 minutes for activities conducted by aircraft that are not fuel constrained and 10 minutes for activities involving aircraft that are fuel constrained (e.g., rotary-wing aircraft, fighter aircraft).

(xviii) Manned surface vessels. For manned surface vessels:

(A) Mitigation zones and requirements. During the use of manned surface vessels, including surfaced submarines, the following mitigation zone requirements apply:

(1) Underway manned surface vessels must maneuver themselves (which may include reducing speed) to maintain the following distances as mission and circumstances allow:

(i) 500 yd (457.2 m) from whales.

(ii) 200 yd (182.9 m) from other marine mammals.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One or more Lookouts on manned underway surface vessels in accordance with the most recent navigation safety instruction.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals immediately prior to manned surface vessels getting underway and while underway.

(2) [Reserved]

(xix) Unmanned vehicles. For unmanned vehicles:

(A) Mitigation zones and requirements. During the use of unmanned surface vehicles and unmanned underwater vehicles already being escorted (and operated under positive control) by a manned surface support vessel, the following mitigation zone requirements apply:

(1) A surface support vessel that is already participating in the event, and has positive control over the unmanned vehicle, must maneuver the unmanned vehicle (which may include reducing its speed) to ensure it maintains the following distances as mission and circumstances allow:

(i) 500 yd (457.2 m) from whales.

(ii) 200 yd (182.9 m) from other marine mammals.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on a surface support vessel that is already participating in the event, and has positive control over the unmanned vehicle.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals immediately prior to unmanned vehicles getting underway and while underway.

(2) [Reserved]

(xx) Towed in-water devices. For towed in-water devices:

(A) Mitigation zones and requirements. During the use of in-water devices towed by an aircraft, a manned surface vessel, or an unmanned surface vehicle or unmanned underwater vehicle already being escorted (and operated under positive control) by a manned surface vessel, the following mitigation zone requirements apply:

(1) Manned towing platforms, or surface support vessels already participating in the event that have positive control over an unmanned vehicle that is towing an in-water device, must maneuver itself or the unmanned vehicle (which may include reducing speed) to ensure towed in-water devices maintain the following distances as mission and circumstances allow:

(i) 250 yd (228.6 m) from marine mammals.

(ii) [Reserved]

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on the manned towing vessel or aircraft, or on a surface support vessel that is already participating in the event and has positive control over an unmanned vehicle that is towing an in-water device.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals immediately prior to and while in-water devices are being towed.

(2) [Reserved]

(xxi) Net deployment. For net deployment:

(A) Mitigation zones and requirements. During net deployment for testing of an Unmanned Underwater Vehicle, the following mitigation zone requirements apply:

(1) If a marine mammal is sighted within 500 yd (457.2 m) of the deployment location, the support vessel will:

(i) Delay deployment of nets until the mitigation zone has been clear for 15 minutes.

(ii) Recover nets if they are deployed.

(2) [Reserved]

(B) Lookout requirements. The following Lookout requirements apply:

(1) One Lookout on the support vessel.

(2) [Reserved]

(C) Mitigation zone observation. Action Proponent personnel must observe the mitigation zones in accordance with the following:

(1) Action Proponent personnel must observe the mitigation zone for marine mammals for 15 minutes prior to the deployment of nets and while nets are deployed.

(2) Nets must be deployed during daylight hours only.

(xxii) Commencement or recommencement conditions. Action Proponents must not commence or recommence an activity after a marine mammal is observed within a relevant mitigation zone until one of the following conditions has been met:

(A) Observed exiting. A Lookout observes the animal exiting the mitigation zone;

(B) Concluded to have exited. A Lookout concludes that the animal has exited the mitigation zone based on its observed course, speed, and movement relative to the mitigation zone;

(C) Clear from additional sightings. A Lookout affirms the mitigation zone has been clear from additional sightings for the activity-specific wait period; or

(D) Platform or target transit. For mobile events, the platform or target has transited a distance equal to double the mitigation zone size beyond the location of the last sighting.

(xxiii) Exceptions to activity-based mitigation for acoustic and explosive stressors and non-explosive ordnance. Activity-based mitigation for acoustic and explosive stressors and non-explosive ordnance will not apply to:

(A) Not operated under positive control. Acoustic sources not operated under positive control (e.g., moored oceanographic sources);

(B) Safety of navigation. Acoustic sources used for safety of navigation (e.g., fathometers);

(C) Aircraft operating at high altitudes. Acoustic sources used or deployed by aircraft operating at high altitudes (e.g., sonobuoys deployed from high altitude (since personnel cannot effectively observe the surface of the water));

(D) Unmanned platforms. Acoustic sources used, deployed, or towed by unmanned platforms except when escort vessels are already participating in the event and have positive control over the source;

(E) Submerged submarines. Acoustic sources used by submerged submarines (e.g., sonar (since personnel cannot conduct visual observation));

(F) De minimis sources. De minimis acoustic sources (e.g., those >200 kilohertz);

(G) Unattended sources. Unattended sources, including those used for acoustic and oceanographic research;

(H) Bow- or wake-riding. Vessel-based, unmanned vehicle-based, or towed in-water acoustic sources when marine mammals (e.g., dolphins) are determined to be intentionally swimming at the bow or alongside or directly behind the vessel, vehicle, or device (e.g., to bow-ride or wake-ride);

(I) Aircraft operating at high altitudes. Explosives deployed by aircraft operating at high altitudes (i.e., altitudes at which marine mammals on the surface cannot be distinguished);

(J) Submerged submarines. Explosives deployed by submerged submarines, except for explosive torpedoes;

(K) Aerial targets. Explosives deployed against aerial targets;

(L) Vessel-launched or shore-launched missile or rocket events. Explosives during vessel-launched or shore-launched missile or rocket events;

(M) De minimis. Explosives used at or below the de minimis threshold (≤0.1 lb (0.05 kg) NEW);

(N) Unmanned platforms. Explosives deployed by unmanned platforms except when escort vessels are already participating in the event and have positive control over the explosive;

(O) Aircraft operating at high altitudes. Non-explosive ordnance deployed by aircraft operating at high altitudes (i.e., altitudes at which marine mammals on the surface cannot be distinguished);

(P) Aerial targets and land-based targets. Non-explosive ordnance deployed against aerial targets and land-based targets;

(Q) Vessel-launched or shore-launched missile or rocket events. Non-explosive ordnance deployed during vessel- or shore-launched missile or rocket events; and

(R) Unmanned platforms. Non-explosive ordnance deployed by unmanned platforms except when escort vessels are already participating in the event and have positive control over ordnance deployment.

(xxiv) Exceptions to activity-based mitigation for physical disturbance and strike stressors. Activity-based mitigation for physical disturbance and strike stressors will not be implemented:

(A) Submerged submarines. By submerged submarines;

(B) Unmanned vehicles. By unmanned vehicles except when escort vessels are already participating in the event and have positive control over the unmanned vehicle movements;

(C) Bow- or wake-riding. When marine mammals (e.g., dolphins) are determined to be intentionally swimming at the bow, alongside the vessel or vehicle, or directly behind the vessel or vehicle (e.g., to bow-ride or wake-ride);

(D) Hauled out pinnipeds. When pinnipeds are hauled out on man-made navigational structures, port structures, and vessels;

(E) Cable laying. By manned surface vessels and towed in-water devices actively participating in cable laying during Modernization & Sustainment of Ranges activities; and

(F) Mission requirements. When impractical based on mission requirements (e.g., during certain aspects of amphibious exercises).

(2) Geographic mitigation areas. The Action Proponents must implement the geographic mitigation requirements described in paragraphs (a)(2)(i) through (xi) of this section.

(i) Hawaii Island marine mammal mitigation area. Figure 1 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Hawaii Island marine mammal mitigation area, the following requirements apply (year-round):

(A) Surface ship hull-mounted mid-frequency active sonar. The Action Proponents must not use more than 300 combined hours of MF1 (regular duty cycle) and MF1C (continuous duty cycle) surface ship hull-mounted mid-frequency active sonar or 20 hours of helicopter dipping sonar (a mid-frequency active sonar source) annually within the mitigation area.

(B) In-water explosives. The Action Proponents must not detonate in-water explosives (including underwater explosives and explosives deployed against surface targets) within the mitigation area.

(ii) Hawaii 4-Islands marine mammal mitigation area. Figure 1 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Hawaii 4-Islands marine mammal mitigation area, the following requirements apply:

(A) Surface ship hull-mounted mid-frequency active sonar. From November 15-April 15, the Action Proponents must not use MF1 or MF1C surface ship hull-mounted mid-frequency active sonar within the mitigation area.

(B) In-water explosives. The Action Proponents must not detonate in-water explosives (including underwater explosives and explosives deployed against surface targets) within the mitigation area (year-round).

(iii) Hawaii humpback whale special reporting mitigation area. Figure 1 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Hawaii humpback whale special reporting mitigation area, the following requirements apply:

(A) Surface ship hull-mounted mid-frequency active sonar. The Action Proponents must report the total hours of MF1 and MF1C surface ship hull-mounted mid-frequency active sonar used from November through May in the mitigation area in their training and testing activity reports submitted to NMFS.

(B) [Reserved]

(iv) Hawaii humpback whale awareness notification mitigation area. Figure 1 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Hawaii humpback whale awareness notification mitigation area, the following requirements apply:

(A) Hawaii humpback whale awareness notification mitigation area notifications. The Action Proponents must broadcast awareness messages to alert applicable assets (and their Lookouts) transiting and training or testing in the Hawaii Range Complex to the possible presence of concentrations of humpback whales from November through May.

(B) Visual observations. Lookouts must use that knowledge to help inform their visual observations during military readiness activities that involve vessel movements, active sonar, in-water explosives (including underwater explosives and explosives deployed against surface targets), or the deployment of non-explosive ordnance against surface targets in the mitigation area.

(v) Northern California large whale mitigation area. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Northern California large whale mitigation area, the following requirements apply:

(A) Surface ship hull-mounted mid-frequency active sonar. From June 1-October 31, the Action Proponents must not use more than 300 combined hours of MF1 and MF1C surface ship hull-mounted mid-frequency active sonar (excluding normal maintenance and systems checks) total during training and testing within the combination of this mitigation area, the Central California large whale mitigation area, and the Southern California blue whale mitigation area.

(B) [Reserved]

(vi) Central California large whale mitigation area. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Central California large whale mitigation area, the following requirements apply:

(A) Surface ship hull-mounted mid-frequency active sonar. From June 1-October 31, the Action Proponents must not use more than 300 combined hours of MF1 and MF1C surface ship hull-mounted mid-frequency active sonar (excluding normal maintenance and systems checks) total during training and testing within the combination of this mitigation area, the Northern California large whale mitigation area, and the Southern California blue whale mitigation area.

(B) [Reserved]

(vii) Southern California blue whale mitigation area. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. Within the Southern California blue whale mitigation area, the following requirements apply:

(A) Surface ship hull-mounted mid-frequency active sonar. From June 1-October 31, the Action Proponents must not use more than 300 combined hours of MF1 and MF1C surface ship hull-mounted mid-frequency active sonar (excluding normal maintenance and systems checks) total during training and testing within the combination of this mitigation area, the Northern California large whale mitigation area, and the Central California large whale mitigation area.

(B) In-water explosives. From June 1-October 31, the Action Proponents must not detonate in-water explosives (including underwater explosives and explosives deployed against surface targets) during large-caliber gunnery, torpedo, bombing, and missile (including 2.75-inch (7 centimeter) rockets) training and testing.

(viii) California large whale awareness messages. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. For California large whale awareness messages, the following requirements apply:

(A) California large whale awareness messages. The Action Proponents must broadcast awareness messages to alert applicable assets (and their Lookouts) transiting and training or testing off the U.S. West Coast to the possible presence of concentrations of large whales, including gray whales (November-June), fin whales (November-May), and mixed concentrations of blue, humpback, and fin whales that may occur based on predicted oceanographic conditions for a given year (e.g., May-November, April-November).

(B) [Reserved]

(ix) California large whale real-time notification mitigation area. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. Within the California large whale real-time notification mitigation area, the following requirements apply:

(A) California large whale real-time notification mitigation area notifications. For each instance an aggregation of large whales (three or more whales within 1 nmi (1.9 km)) is sighted in the area between 32-33 degrees North and 117.2-119.5 degrees West, Action Proponent surface vessels must report the sightings to other Action Proponent vessels in the vicinity. Reported sightings will be made as soon as operationally and safely feasible.

(B) [Reserved]

(x) San Nicolas Island pinniped haulout mitigation area. Figure 2 to this paragraph (a)(2) shows the location of the mitigation areas. Within the San Nicolas Island pinniped haulout mitigation area, the following requirements apply:

(A) Haulouts. Navy personnel must not enter pinniped haulout or rookery areas. Personnel may be adjacent to pinniped haulouts and rookery prior to and following a launch for monitoring purposes.

(B) Missile and target use. Missiles and targets must not cross over pinniped haulout areas at altitudes less than 305 m (1,000 ft), except in emergencies or for real-time security incidents. For unmanned aircraft systems (UAS), the following minimum altitudes will be maintained over pinniped haulout areas and rookeries: Class 0-2 UAS will maintain a minimum altitude of 300 ft (92 m); Class 3 UAS will maintain a minimum altitude of 500 ft (153 m); Class 4 or 5 UAS will not be flown below 1,000 ft (305 m).

(C) Number of events. The Navy may not conduct more than 40 launch events annually and 10 launch events at night annually.

(D) Scheduling. Launch events must be scheduled to avoid the peak pinniped pupping seasons (from January through July) to the maximum extent practicable.

(E) Monitoring plan. The Navy must implement a monitoring plan using video and acoustic monitoring of up to three pinniped haulout areas and rookeries during launch events that include missiles or targets that have not been previously monitored for at least three launch events.

(F) Review of launch procedure. The Navy must review the launch procedure and monitoring methods, in cooperation with NMFS, if any incidents of injury or mortality of a pinniped are discovered during post-launch surveys, or if surveys indicate possible effects to the distribution, size, or productivity of the affected pinniped populations as a result of the specified activities. If necessary, appropriate changes will be made through modification to the LOA prior to conducting the next launch of the same vehicle.

(xi) National security requirement. Should national security require the Action Proponents to exceed a requirement(s) in paragraphs (a)(2)(i) through (x) of this section, Action Proponent personnel must provide NMFS with advance notification and include the information (e.g., sonar hours, explosives usage) in its annual activity reports submitted to NMFS.

Figure 2 to paragraph (a)(2)—Geographic Mitigation Areas for Marine Mammals in the California Study Area

(3) Cetacean live stranding. In the event of a cetacean live stranding (or near-shore atypical milling) event within the HCTT Study Area or within 50 km (27 nmi) of the boundary of the HCTT Study Area, where the NMFS Marine Mammal Stranding Network is engaged in herding or other interventions to return animals to the water, NMFS Office of Protected Resources will advise the Action Proponents of the need to implement shutdown procedures for all active acoustic sources or explosive devices within 50 km of the stranding. Following this initial shutdown, NMFS will communicate with the Action Proponents to determine whether circumstances support modification of the shutdown zone. The Action Proponents may decline to implement all or part of the shutdown if the holder of the LOA, or his/her designee, determines that it is necessary for national security. Shutdown procedures for live stranding or milling cetaceans include the following:

(i) Shutdown no longer needed. If at any time, the marine mammal(s) die or are euthanized, or if herding/intervention efforts are stopped, NMFS will immediately advise that the shutdown around the animals' location is no longer needed;

(ii) Shutdown procedures remain in effect. Otherwise, shutdown procedures will remain in effect until NMFS determines and advises that all live animals involved have left the area (either of their own volition or following an intervention); and

(iii) Further observations. If further observations of the marine mammals indicate the potential for re-stranding, additional coordination will be required to determine what measures are necessary to minimize that likelihood (e.g., extending the shutdown or moving operations farther away) and to implement those measures as appropriate.

(b) [Reserved]

authority: 16 U.S.C. 1361

source: 74 FR 28343, June 15, 2009, unless otherwise noted.

cite as: 50 CFR 218.74