(a) Regulations in this subpart apply only to the U.S. Navy (Navy) for the taking of marine mammals that occurs in the area described in paragraph (b) of this section and that occurs incidental to the activities listed in paragraph (c) of this section. Requirements imposed on the Navy must be implemented by those persons they authorize or fund to conduct activities on their behalf.

(b) The taking of marine mammals by the Navy under this subpart may be authorized in a letter of authorization (LOA) only if it occurs within the Pacific Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) Sonar Study Area. The Pacific SURTASS LFA Sonar Study Area is delineated in Figure 1 to this paragraph (b) and includes the western and central North Pacific Ocean and eastern Indian Ocean, not including the western Indian Ocean or Sea of Okhotsk.

(c) The taking of marine mammals by the Navy is authorized only if it occurs incidental to the Navy conducting military readiness activities, including those in the following categories:

(1) Training;

(2) Maintenance and upgrades; and

(3) Exercises.

Regulations in this subpart are effective from August 12, 2026, through August 11, 2033.

(a) Under LOAs issued pursuant to § 216.106 of this chapter and this subpart, the Navy may incidentally, but not intentionally, take marine mammals within the area described in § 218.230(b) by Level A harassment and Level B harassment associated with the use of SURTASS LFA sonar during activities listed in § 218.230(c), provided the activity is in compliance with all terms, conditions, and requirements of this subpart and the applicable LOA.

(b) The incidental take of marine mammals by the activities listed in § 218.230(c) is limited to the following species:

Except incidental take described in § 218.232 and authorized by an LOA issued under § 216.106 of this chapter and this subpart, it shall be unlawful for any person to do the following in connection with the activities described in this subpart:

(a) Violate, or fail to comply with, the terms, conditions, and requirements of this subpart or an LOA issued under § 216.106 of this chapter and this subpart;

(b) Take any marine mammal not specified in § 218.232(b);

(c) Take any marine mammal specified in § 218.232(b) in any manner other than as specified in the LOA;

(d) Take a marine mammal specified in § 218.232(b) after NMFS determines such taking results in more than a negligible impact on the species or stock of such marine mammal; or

(e) Take a marine mammal specified in § 218.232(b) after NMFS determines such taking is having, or may have, an unmitigable adverse impact on the availability of the species or stock for taking for subsistence uses.

When conducting the activities identified in § 218.230(c), the mitigation measures contained in this section and any LOA issued under § 216.106 of this chapter and this subpart must be implemented by Navy personnel or contractors who are trained according to the requirements in the LOA. If Navy contractors are serving on behalf of Navy personnel, Navy contractors must follow the mitigation applicable to Navy personnel. These mitigation measures include, but are not limited to:

(a) General operating procedures. Prior to SURTASS LFA sonar activities, the Navy must promulgate executive guidance for the administration and execution of and compliance with the regulations in this subpart and LOA.

(b) Manned surface vessel mitigation. Manned surface vessel mitigation applies to Auxiliary General Ocean Surveillance (T-AGOS) vessels underway and must be implemented to the maximum extent practical based on the prevailing circumstances, including consideration of safety of vessels, towing platforms, and crews, as well as maneuverability restrictions, consistent with the following:

(1) Immediately prior to getting underway and while underway, Lookouts will observe for marine mammals;

(2) While underway, Navy personnel must maneuver the manned surface vessels (which may include reducing speed) to maintain a distance of at least 457.2 meters (m) (500 yards (yd)) around observed whales and 182.9 m (200 yd) around all other marine mammals (except bow- or wake-riding dolphins), providing it is safe to do so. No further action is necessary if a dolphin continues to approach the vessel after the vessel has made one course and/or speed change.

(3) Pedestal-mounted `Big Eye' (20 x 110 millimeter (mm)) binoculars (if installed) shall be used to assist in the detection of marine mammals in the vicinity of the vessel. If the presence of marine mammals is detected acoustically, Lookouts posted on the vessel shall increase the vigilance of their visual observation.

(4) Manned surface vessel mitigation will not be implemented if one or more of the following conditions applies:

(i) 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);

(ii) The vessel's safety is threatened; or

(iii) Doing so is impractical based on mission requirements (e.g., restricted ability to maneuver during towing activities).

(c) SURTASS LFA sonar mitigation zone; suspension and delay. If a marine mammal is detected, through monitoring required under § 218.235, within or about to enter within 2,000 yd (1.8 kilometers (km)) of the SURTASS LFA source (i.e., the LFA mitigation zone), Navy personnel must immediately delay or suspend SURTASS LFA sonar transmissions.

(d) Recommencement of SURTASS LFA sonar transmissions. The following requirements for commencement or recommencement of SURTASS LFA sonar transmissions apply:

(1) Navy personnel must not commence or recommence SURTASS LFA sonar transmissions earlier than 15 minutes after:

(i) All marine mammals have left the area of the 2,000-yd (1.8 km) LFA sonar mitigation zone; and

(ii) There is no further detection of any marine mammal within the 2,000-yd (1.8 km) LFA sonar mitigation zone as determined by the visual, passive acoustic, and active acoustic high frequency monitoring described in § 218.235.

(2) [Reserved]

(e) Ramp-up of the high-frequency/marine mammal monitoring (HF/M3) active sonar. The following requirements for ramp-up procedures for the HF/M3 active sonar apply:

(1) Prior to full-power use, Navy personnel must ramp up the HF/M3 active sonar power level beginning at a maximum source sound pressure level of 180 decibels referenced to 1 microPascal (dB re 1 µPa) root-mean-square (RMS) sound pressure level (SPL) in 10-dB increments to full operating levels over a period of no less than 5 minutes. Navy personnel must implement this ramp-up procedure:

(i) At least 30 minutes prior to any SURTASS LFA sonar transmissions; and

(ii) Any time after the HF/M3 source has been powered down for more than 2 minutes.

(2) Navy personnel must not increase the HF/M3 SPL once a marine mammal is detected; and

(3) Ramp-up may recommence once marine mammals are no longer detected by all of the monitoring methods.

(f) Geographic mitigation. The Navy must implement the geographic mitigation requirements described in paragraphs (f)(1) through (f)(3) of this section.

(1) The activities specified in § 218.230(c) must be conducted such that:

(i) The received level of SURTASS LFA sonar transmissions will not exceed 180 dB re 1 µPa RMS SPL within 22 km (12 nautical miles (nmi)) from any emergent land, including offshore islands;

(ii) The received level of SURTASS LFA sonar transmissions will not exceed 180 dB re 1 µPa RMS SPL at a distance of 1 km (0.5 nmi) seaward of the outer perimeter of any Offshore Biologically Important Area (OBIA) in the SURTASS LFA Study Area during the effective period specified. OBIAs and the related effective periods are listed in paragraph (f)(2) of this section or may be subsequently identified through the adaptive management process specified in § 218.237(c)(1). The boundaries and effective periods of the OBIAs will be kept on file in NMFS' Office of Protected Resources (OPR) and on its website.

(iii) No more than 25 percent of the sound source amount analyzed (no more than 275 hours in a given year) of SURTASS LFA sonar for training and testing will be conducted within 18.5 km (10 nmi) of any single OBIA during any year; and

(iv) SURTASS LFA sonar activities will not occur within territorial seas of foreign nations, which are areas from 0-22 km (0-12 nmi) from shore.

(2) Figure 1 to this paragraph (f)(1) shows the location of the OBIAs. Table 1 to paragraph (f)(1) shows the specified timeframes when the requirements from paragraph (f)(1) apply.

(3) Should national security require the Navy to exceed a requirement in paragraph (f)(1)(iii) of this section, personnel conducting the activity are required to obtain approval through the chain of command prior to commencement of the activity. The Navy must provide NMFS with notification as soon as is practicable and include the information (e.g., sonar hours in exceedance of 25 percent) in its annual activity reports submitted to NMFS.

(g) Cetacean live stranding. In the event of a cetacean live stranding (or near-shore atypical milling) event within the Study Area or within 50 km (27 nmi) of the boundary of the Study Area, where the NMFS Marine Mammal Stranding Network is engaged in herding or other interventions to return animals to the water, NMFS OPR will advise the Navy of the need to implement shutdown procedures for all active acoustic sources within 50 km of the stranding. Following this initial shutdown, NMFS will communicate with the Navy to determine whether circumstances support modification of the shutdown zone. The Navy 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:

(1) 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;

(2) Shutdown procedures remain in effect. Otherwise, shutdown procedures must 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

(3) Further observations. If further observations of the marine mammals indicate the potential for re-stranding, additional coordination with NMFS 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.

The Navy must implement the following monitoring and reporting requirements when conducting the specified activities:

(a) Notification of take. If the Navy reasonably believes that the specified activity identified in § 218.230 resulted in the mortality or serious injury of any marine mammals, or in any Level A harassment or Level B harassment of marine mammals not identified in this subpart, then the Navy must notify NMFS immediately or as soon as operational security considerations allow.

(b) Monitoring and reporting under the LOA. The Navy must conduct all monitoring and reporting required under the LOA.

(c) Notification of injured, live stranded, or dead marine mammals. Navy personnel must abide by the Notification and Reporting Plan, which sets out notification, reporting, and other requirements when dead, injured, or live stranded marine mammals are detected. The Notification and Reporting Plan is available at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

(d) Mitigation monitoring. The Navy must conduct all monitoring required under the LOA, including:

(1) Visual observations. Visual observations must be conducted by trained Lookouts on the vessel's bridge using standard binoculars (7x) and the naked eye. Pedestal-mounted 'Big Eye' (20 x 110 mm) binoculars (if installed) must be used to assist in the detection of marine mammals in the vicinity of the vessel.

(i) Lookouts must conduct visual monitoring from the vessel's bridge during all daylight hours (30 minutes before sunrise until 30 minutes after sunset);

(ii) During training and testing activities that employ SURTASS LFA sonar in the active mode, Lookouts must conduct visual monitoring beginning 30 minutes before sunrise or 30 minutes before SURTASS LFA sonar begins to transmit and continue until 30 minutes after sunset or until 15 minutes after the SURTASS LFA sonar transmissions cease;

(iii) Lookouts must log all detections of marine mammals during SURTASS LFA sonar transmissions during training and testing activities;

(iv) Lookouts must record the number, identification, bearing, and range of observed marine mammals during training and testing activities, and must identify marine mammals to the lowest taxonomic level possible; and

(v) Lookouts must continue visual observations until 15 minutes have passed since the last detection of the marine mammal.

(2) Passive Acoustic Monitoring. During activities specified in § 218.230(c) that employ SURTASS LFA sonar in the active mode, Navy personnel must conduct passive acoustic monitoring using the SURTASS towed horizontal line array to detect vocalizing marine mammals.

(i) Passive acoustic monitoring must begin 30 minutes before the SURTASS LFA sonar begins to transmit and continue until 15 minutes after SURTASS LFA sonar transmissions cease; and

(ii) If a detected sound is estimated to be from a vocalizing marine mammal, the sonar technician must notify the senior military member-in-charge, who must alert the HF/M3 sonar operator and Lookouts (during daylight).

(3) Active Acoustic (HF/M3) Monitoring. During activities specified in § 218.230(c) that employ SURTASS LFA sonar in the active mode, Navy personnel must use the HF/M3 sonar to detect, locate, and track marine mammals in relation to the SURTASS LFA sonar array and the LFA mitigation zone, subject to the ramp-up requirements in § 218.234(e).

(i) HF/M3 sonar monitoring must begin 30 minutes before the SURTASS LFA sonar begins to transmit and continue until 15 minutes after SURTASS LFA sonar transmissions cease; and

(ii) If a marine mammal is detected during HF/M3 monitoring within the SURTASS LFA mitigation zone, the sonar operator must notify the senior military member-in-charge.

(4) Cessation of Monitoring. Navy personnel must continue monitoring either for at least 15 minutes after completion of the SURTASS LFA sonar training and testing transmission or, if marine mammals are exhibiting unusual changes in behavioral patterns, until behavior patterns return to normal or conditions prevent continued observations.

(e) Designation of qualified individuals. The Navy must designate qualified on-site individuals to conduct the mitigation, monitoring, and reporting activities specified in these regulations and LOA issued under §§ 216.106 of this chapter and 218.236.

(f) Marine Mammal Monitoring Program. The Navy must continue to assess data from the Marine Mammal Monitoring Program and work toward making some portion of that data, after appropriate security reviews, available to scientists with appropriate clearances. Any portions of the analyses conducted by these scientists based on these data that are determined to be unclassified after appropriate security reviews will be made publicly available.

(g) Annual Pacific SURTASS LFA Study Area marine species monitoring report. The Navy must submit an unclassified annual report (Annual Pacific SURTASS LFA Study Area Marine Species Monitoring Report) of the Study Area marine species monitoring describing the implementation and results from the previous calendar year. Data collection methods will be standardized across range complexes and the Study Area to allow for comparison in different geographic locations. The draft report must be submitted annually to the Director, Office of Protected Resources, NMFS. NMFS will submit any comments or questions on the report within 3 months of receipt. The report will be considered final after the Navy has addressed NMFS' comments, or 3 months after submittal of the draft if NMFS does not provide comments on the draft report. The report must describe progress of knowledge made with respect to new or continuing scientific knowledge of marine mammals.

(h) Quick look reports. In the event that the sound source amount analyzed in the preambles of the Marine Mammal Protection Act (MMPA) proposed rule (91 FR 11618, March 10, 2026) and this final rule are exceeded within a given reporting year, the Navy must submit a preliminary report detailing the exceedance within 21 days after the anniversary date of issuance of the LOA.

(i) Annual Pacific SURTASS LFA training and testing report. The Navy must submit a classified and unclassified report (Annual Pacific SURTASS LFA Training and Testing Report) to the Director, Office of Protected Resources, NMFS, annually within 3 months of the 1-year anniversary of the date of the issuance of the LOA. For the final reporting year, the Navy must submit a final/close-out (year 7) Annual Pacific SURTASS LFA Training and Testing Report. NMFS will submit any comments or questions on the report within 1 month of receipt. The report will be considered final after the Navy has addressed NMFS' comments, or 1 month after submittal of the drafts if NMFS does not provide comments on the draft report.

(1) Annual Reports. The Annual Pacific SURTASS LFA Training and Testing Report must include elements listed below. The analysis in the report must be based on the data from the current year's report and data collected from previous annual reports.

(i) Dates, times, and locations of each vessel during each training and testing activity;

(ii) Information on sonar transmissions during each training and testing activity, including:

(A) Total annual hours or quantity of each bin of sonar used in all training and testing events,

(B) Cumulative sonar use quantity from previous years' reports through the current year, and

(C) Records of any sonar delays or suspensions due to the presence of marine mammals.

(iii) Marine mammal detection information during specified activities where mitigation was implemented:

(A) Date, time, and location of sighting;

(B) Species (if not possible, indication of whale/dolphin/pinniped);

(C) Number of individuals;

(D) Initial Detection Sensor (e.g., visual, passive acoustic, HF/M3 sonar);

(E) Indication of specific type of platform observation was made from (including, for example, what type of surface vessel or testing platform);

(F) Length of time observers maintained visual contact with marine mammal;

(G) Sea state;

(H) Visibility;

(I) Sound source in use at the time of sighting;

(J) Indication of whether animal was less than 200 yd (182.9 m), 200 to 500 yd (182.9 to 457.2 m), 500 to 1,000 yd (457.2 to 914.4 m), 1,000 to 2,000 yd (914.4 m to 1.8 km), or greater than 2,000 yd (1.8 km) from sonar source;

(K) Whether operation of sonar sensor was delayed, or sonar was powered or shut down, and the length of delay;

(L) Bearing and range from the vessel; and

(M) For visual observations, Lookouts must report the observed behavior of the animal(s) in plain language and without trying to categorize in any way (such as animal closing to bow ride, paralleling course/speed, floating on surface and not swimming, etc.) and if any calves were present.

(iv) Delays or suspensions of LFA sonar transmissions due to mitigation monitoring protocol. Information on marine mammal detections would include marine mammal type (i.e., whales, dolphins) and/or species identifications, number of marine mammals detected, time of detections, type of detection (visual, passive acoustic, HF/M3 sonar), bearing and range from the vessel, abnormal behavior (if any), and remarks or narrative as necessary.

(v) An evaluation (based on data gathered during the reporting year) of the effectiveness of mitigation measures designed to minimize the received level to which marine mammals may be exposed. This evaluation must identify the specific observations that support any conclusions the Navy reaches about the effectiveness of the mitigation.

(2) Final/close-out report. The final/close-out report at the conclusion of the authorization period (year 7) will also serve as the comprehensive close-out report and provide the annual totals for each sound source bin with a comparison to the annual amount analyzed and the 7-year total for each sound source bin with a comparison to the 7-year amount analyzed.

(j) National security requirement. If the Navy invokes the national security requirement described in § 218.234(f)(3), Navy personnel must include information about the event in its Annual Pacific SURTASS LFA Training and Testing Report.

(a) To incidentally take marine mammals pursuant to this subpart, the Navy must apply for and obtain an LOA.

(b) An LOA, unless suspended or revoked, may be effective for a period of time not to exceed the expiration date of this subpart.

(c) The LOA will set forth:

(1) Permissible methods of incidental taking;

(2) Geographic areas for incidental taking;

(3) Means of effecting the least practicable adverse impact (i.e., mitigation) on the species and stocks of marine mammals and their habitat; and

(4) Requirements for monitoring and reporting.

(d) Issuance of the LOA must be based on a determination that the level of taking is consistent with the findings made for the total taking allowable under the regulations of this subpart.

(e) Notice of issuance, modification, or denial of the LOA will be published in the Federal Register within 30 days of a determination.

(f) In the event of projected changes to mitigation, monitoring, or reporting measures required by an LOA, the Navy must apply for and obtain a modification of the LOA under § 218.237.

(a) NMFS may modify the mitigation, monitoring, or reporting measures in a LOA issued under §§ 216.106 of this chapter and 218.236 of this subpart at the request of the Navy or NMFS' own initiative if:

(1) The anticipated effects of the modified measure are the same as those described and analyzed for this subpart;

(2) The modified measure has a reasonable likelihood of effectiveness;

(3) NMFS determines the modified measure does not change the findings made for this subpart; and

(4) Navy concurs with the modified measure and that, where applicable, it is practicable for the Navy in the context of personnel safety, practicality of implementation, and impacts on the effectiveness of the military readiness activity.

(b) If modifications to the mitigation, monitoring, or reporting measures are substantial NMFS will publish a notice of the proposed LOA modification in the Federal Register and solicit public comment.