The proposed action would result in the following increases (above those conducted in previous years, i.e., the No Action Alternative in the Navy's DEIS) in activities associated with the annual take of marine mammals:

Overview of the MIRC

The U.S. military has been training and operating in the area now defined as the MIRC for over 100 years. The MIRC Study Area (see figure 11 in the Navy's application) is located in the Western Pacific (WestPac) and consists of three primary components: ocean surface and undersea areas, special use airspace (SUA), and training land areas. The ocean surface and undersea areas extend from the international waters south of Guam to north of Pagan (CNMI), and from the Pacific Ocean east of the Mariana Islands to the middle of the Philippine Sea to the west, encompassing 501,873 square nautical miles (nm\2\) (1,299,851 square kilometers [km\2\]) of open ocean and littorals (coastal areas). The MIRC Study Area includes ocean areas in the Philippine Sea, Pacific Ocean, and exclusive economic zones (EEZs) of the United States and Federal States of Micronesia (FSM). The MIRC Study Area includes land ranges and training area/facilities on Guam, Rota, Tinian, Saipan, and Farallon de Medinilla (FDM), encompassing 64 nm\2\ (220 km\2\) of land. Special Use Airspace (SUA) consists of Warning Area 517 (W517), restricted airspace over FDM (R7201), and Air Traffic Control Assigned Airspace (ATCAA) encompassing 63,000 nm\2\ (216,000 km\2\) of airspace. For range management and scheduling purposes, the MIRC is divided into training areas under different controlling authorities.

Guam is located roughly three quarters of the distance from Hawaii to the Philippines, about 1,600 miles east of Manila and 1,550 miles southeast of Tokyo. The southern extent of the Commonwealth of the Northern Mariana Islands (CNMI) is located 40 miles north of Guam (Rota Island) and extends 330 miles to the northwest. Saipan, the CNMI capital, is 3,300 miles west of Honolulu and 1,470 miles south southeast of Tokyo. The MIRC is of particular significance for the training of U.S. military forces in the Western Pacific because of its location. As the westernmost complex in U.S. territory, it provides the only opportunity for forwarddeployed U.S. forces to train on U.S. owned lands without having to return to Hawaii or the continental United States.

The seafloor of the MIRC is characterized by the Mariana Trench, the Mariana Basin, the Mariana Ridge, ridges, numerous seamounts, hydrothermal vents, and volcanic activity. These areas are comprised of very deep water with a very rapid transition from the shelf to deep water. The Mariana Trench is located east to southeast of Guam and the Mariana Islands and is characterized by deep depths of 16,404 to 32,808 feet [ft] (5,000 to 10,000 m) (Fryer et al., 2003). The Mariana Basin is located west of Guam and the Mariana Islands, and is characterized by an average depth of 11,483 ft (Taylor and Martinez 2003; Yamazaki et al., 1993). The Mariana Ridge consists of Guam and the Mariana Islands and the waters out to the Mariana Trench, and is characterized by shallow water transitioning to deep water of 11,483 ft (3,500 m) (Taylor and Martinez 2003; Yamazaki et al., 1993). The bottom substrate covering the seafloor in the MIRC is primarily volcanic or marine in nature (Eldredge, 1983).

The waters of the MIRC Study Area undergo an annual cycle of temperature change, however this temperature flux is only a few degrees each year, as would be expected from a tropical climate. The temperature throughout the year ranges from about 25[deg] to 31 [deg]C with an annual mean temperature of 27[deg] to 28 [deg]C for the years ranging from 1984 to 2003 (National Oceanic and Atmospheric Administration [NOAA] 2004). Temperatures increase during the summer and autumn months with peak temperatures occurring in September/ October.

The water column in the MIRC Study Area contains a wellmixed surface layer ranging from 295 ft to 410 ft (90 to 125 m). Immediately below the mixed layer is a rapid decline in temperature to the cold deeper waters. Unlike more temperate climates, the thermocline is relatively stable, rarely turning over and mixing the more nutrient rich waters of the deeper ocean in to the surface layer. This constitutes what has been defined as a ``significant'' surface duct (a mixed layer of constant water temperature extending from the sea surface to 100 feet or more), which influences the transmission of sound in the water. This factor has been included in the modeling analysis of marine mammal impacts.

Marianas Trench Marine National Monument

The Marianas Trench Marine National Monument (the `Monument') was [[Page 53798]]
established in January 2009 by Presidential Proclamation under the authority of the Antiquities Act (16 U.S.C. 431). The Monument consists of approximately 71,897 square nautical miles (246,600 square kilometers) of submerged lands and waters of the Mariana Archipelago and was designated with the purpose of protecting the submerged volcanic areas of the Mariana Ridge, the coral reef ecosystems of the waters surrounding the islands of Farallon de Pajaros, Maug, and Asuncion in the Commonwealth of the Northern Mariana Islands, and the Mariana Trench. The Monument includes the waters and submerged lands of the three northernmost Mariana Islands (the `Islands Unit') and only the submerged lands of designated volcanic sites (the `Volcanic Unit') and the Mariana Trench (the `Trench Unit') to the extent described as follows: The seaward boundaries of the Islands Unit of the monument extend to the lines of latitude and longitude which lie approximately 50 nautical miles (93 kilometers) from the mean low water line of Farallon de Pajaros (Uracas), Maug, and Asuncion. The inland boundary of the Islands Unit of the monument is the mean low water line. The boundary of the Trench Unit of the Monument extends from the northern limit of the EEZ of the United States in the Commonwealth of the Northern Mariana Islands to the southern limit of the Exclusive Economic Zone of the United States in Guam approximately following the points of latitude and longitude identified in Figure 3.61 of the MIRC DEIS. The boundaries of the Volcanic Unit of the Monument include a 1 nautical mile radius centered on each of the islands' volcanic features.

The Monument contains objects of scientific interest, including the largest active mud volcanoes on Earth. The Champagne vent, located at the Eifuku submarine volcano, produces almost pure liquid carbon dioxide. This phenomenon has only been observed at one other site in the world. The Sulfur Cauldron, a pool of liquid sulfur, is found at the Daikoku submarine volcano. The only other known location of molten sulfur is on Io, a moon of Jupiter. Unlike other reefs across the Pacific, the northernmost Mariana reefs provide unique volcanic habitats that support marine biological communities requiring basalt. Maug Crater represents one of only a handful of places on Earth where photosynthetic and chemosynthetic communities of life are known to come together.

The waters of the Monument's northern islands are among the most biologically diverse in the Western Pacific and include the greatest diversity of seamount and hydrothermal vent life yet discovered. These volcanic islands are ringed by coral ecosystems with very high numbers of apex predators, including large numbers of sharks. They also contain one of the most diverse collections of stony corals in the Western Pacific. The northern islands and shoals in the Monument have substantially higher large fish biomass, including apex predators, than the southern islands and Guam. The waters of Farallon de Pajaros (also known as Uracas), Maug, and Asuncion support some of the largest biomass of reef fishes in the Mariana Archipelago.

A portion of the Monument lies within the MIRC, including a small area on the northern border of the MIRC as well as the Volcanic Unit and the Trench Unit (See Figure 3.61). Any of the activities identified under the Proposed Action could take place within areas included in the Monument, where they overlap. The Presidential Proclamation establishing the Monument indicates that the prohibitions required by the Proclamation shall not apply to activities and exercises of the Armed Forces, but also that the Armed Forces shall ensure, by the adoption of appropriate measures not impairing operations or operational capabilities, that its vessels and aircraft act in a manner consistent, so far as is reasonable and practicable, with the Proclamation.

Specified Activities

As mentioned above, the Navy has requested MMPA authorization to take marine mammals incidental to training or RDT&E activities in the MIRC that would result in the generation of sound or pressure waves in the water at or above levels that NMFS has determined will likely result in take (see Acoustic Take Criteria Section), either through the use of MFAS/HFAS or the detonation of explosives in the water. These activities are discussed in the subsections below. In addition to use of active sonar sources and explosives, these activities include the operation and movement of vessels that are necessary to conduct the training, and the effects of this part of the activities are also analyzed in this document.

The Navy's application also briefly summarizes Maritime and Air Interdiction of Maritime Targets and Air Combat Maneuvers; however, these activities are primarily air based and do not utilize sound sources or explosives in the water. No take of marine mammals is anticipated to result from these activities and, therefore, they are not discussed further.

Activities Utilizing Active Sonar Sources

For the MIRC, the training activities that utilize active tactical sonar sources fall primarily into the category of Antisubmarine Warfare (ASW). This section includes a description of ASW, the active acoustic devices used in ASW exercises, and the exercise types in which these acoustic sources are used.

ASW Training and Active Sonar

ASW involves helicopter and sea control aircraft, ships, and submarines, operating alone or in combination, to locate, track, and neutralize submarines. Various types of active and passive sonars are used by the Navy to determine water depth, locate mines, and identify, track, and target submarines. Passive sonar ``listens'' for sound waves by using underwater microphones, called hydrophones, which receive, amplify and process underwater sounds. No sound is introduced into the water when using passive sonar. Passive sonar can indicate the presence, character and movement of submarines. However, passive sonar provides information about only the bearing (direction) to a sound emitting source; it does not provide an accurate range (distance) to the source. Also, passive sonar relies on the underwater target itself to provide sufficient sound to be detected by hydrophones. Active sonar is needed to locate objects that emit little or no noise (such as mines or dieselelectric submarines operating in electric mode) and to establish both bearing and range to the detected contact.

Active sonar transmits pulses of sound that travel through the water, reflect off objects and return to a receiver. By knowing the speed of sound in water and the time taken for the sound wave to travel to the object and back, active sonar systems can quickly calculate direction and distance from the sonar platform to the underwater object. There are three types of active sonar: Low frequency, mid frequency, and highfrequency.

MFAS, as defined in the Navy's MIRC LOA application, operates between 1 and 10 kHz, with detection ranges up to 10 nm (19 km). Because of this detection ranging capability, MFAS is the Navy's primary tool for conducting ASW. Many ASW experiments and exercises have demonstrated that the improved capability (of MFAS over other sources) for long range detection of adversary submarines before they are able to conduct an attack is essential to U.S.
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ship survivability. Today, ASW is the Navy's number one warfighting priority. Navies across the world utilize modern, quiet, diesel electric submarines that pose the primary threat to the U.S. Navy's ability to perform a number of critical missions. Extensive training is necessary if Sailors on ships and in strike groups are to gain proficiency in using MFAS. If a strike group does not demonstrate MFAS proficiency, it cannot be certified as combat ready.

HFAS, as defined in the Navy's MIRC LOA application, operates at frequencies greater than 10 kilohertz (kHz). At higher acoustic frequencies, sound rapidly dissipates in the ocean environment, resulting in short detection ranges, typically less than five nm (9 km). Highfrequency sonar is used primarily for determining water depth, hunting mines and guiding torpedoes.

Surveillance Towed Array Sensor System Low Frequency Active (SURTASS LFA) sonar operates below 1 kHz and is designed to detect extremely quiet dieselelectric submarines at ranges far beyond the capabilities of MFA sonars. There are currently only two ships in use by the Navy that are equipped with LFA sonar; both are ocean surveillance vessels operated by Military Sealift Command (MSC). Acoustic Sources Used for ASW Exercises in the MIRC

Modern sonar technology has developed a multitude of sonar sensor and processing systems. In concept, the simplest active sonars emit omnidirectional pulses (``pings'') and time the arrival of the reflected echoes from the target object to determine range. More sophisticated active sonar emits an omnidirectional ping and then rapidly scans a steered receiving beam to provide directional, as well as range, information. More advanced active sonars transmit multiple preformed beams, listening to echoes from several directions simultaneously and providing efficient detection of both direction and range. The types of active sonar sources employed during ASW active sonar training exercises in the MIRC are identified in Table 1.

The SURTASS LFA system may also be used during some of the Navy's training and testing scenarios within the MIRC Study Area (see SURTASS LFA subsection below), however, that system's use was analyzed in other environmental documentation (DON 1999, 2002b, 2007a; NOAA 2002a, 2007). BILLING CODE 351022P
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ASW sonar systems are deployed from certain classes of surface ships, submarines, helicopters, and fixedwing maritime patrol aircraft (MPA). Maritime patrol aircraft is a category of fixedwing aircraft that includes the current P3C Orion, and the future P8 Poseidon multimission maritime aircraft. The surface ships used are typically equipped with hullmounted sonars (passive and active) for the detection of submarines. Fixedwing MPA are used to deploy both active and passive sonobuoys to assist in locating and tracking submarines or ASW targets during the exercise. Helicopters are used to deploy both active and passive sonobuoys to assist in locating and tracking submarines or ASW targets during the exercise, and to deploy dipping sonar. Submarines are equipped with passive sonar sensors used to locate and prosecute other submarines and/or surface ships during the exercise. The platforms used in ASW exercises are identified below.

Surface Ship SonarsA variety of surface ships participate in training events, including the Fast Frigate (FFG) and the Guided Missile Destroyer (DDG), and the guided missile cruiser (CG). These three classes of ship are equipped with active as well as passive tactical sonars for mine avoidance and submarine detection and tracking. DDG and CG class ships are equipped with the AN/SQS53 sonar system (the most powerful system), with a nominal source level of 235 decibels (dB) re 1 [mu]Pa @ 1 m. The FFG class ship uses the SQS56 sonar system, with a nominal source level of 225 decibels (dB) re 1 [mu]Pa @ 1 m. Sonar ping transmission durations were modeled as lasting 1 second per ping and omnidirectional, which is a conservative assumption that will overestimate potential effects. Actual ping durations will be less than 1 second. The AN/SQS53 hullmounted sonar transmits at a center frequency of 3.5 kHz. The SQS56 transmits at a center frequency of 7.5 kHz. Details concerning the tactical use of specific frequencies and the repetition rate for the sonar pings is classified but was modeled based on the required tactical training setting.

Submarine SonarsSubmarine sonars (e.g., AN/BQQ10) are used to detect and target enemy submarines and surface ships. Because submarine active sonar use is very rare and in those rare instances, very brief, it is extremely unlikely that use of active sonar by submarines would have any measurable effect on marine mammals. In addition, submarines have a high frequency AN/BQS15 sonar used for navigation safety and mine avoidance that is not unlike a fathometer in source level or output. There is, at present, no mine training range in the MIRC area. Therefore, given its limited use and rapid attenuation as a high frequency source, the AN/BQS15 is not expected to result in the take of marine mammals.

Aircraft Sonar SystemsAircraft sonar systems that would operate in the MIRC include sonobuoys and dipping sonar. Sonobuoys may be deployed by maritime patrol aircraft or helicopters; dipping sonars are used by carrierbased helicopters. A sonobuoy is an expendable device used by aircraft for the detection of underwater acoustic energy and for conducting vertical water column temperature measurements. Most sonobuoys are passive, but some can generate active acoustic signals, as well. Dipping sonar is an active or passive sonar device lowered on cable by helicopters to detect or maintain contact with underwater targets. During ASW training, these systems' active modes are only used briefly for localization of contacts and are not used in primary search capacity.

Extended Echo Ranging and Improved Extended Echo Ranging (EER/IEER) SystemsEER/IEER are airborne ASW systems used to conduct ``large area'' searches for submarines. These systems are made up of airborne avionics ASW acoustic processing and sonobuoy types that are deployed in pairs. The EER/IEER System's active sonobuoy component, the AN/SSQ 110A Sonobuoy, generates an explosive sound impulse and a passive sonobuoy (ADAR, AN/SSQ101A) that would ``listen'' for the return echo that has been bounced off the surface of a submarine. These sonobuoys are designed to provide underwater acoustic data necessary for naval aircrews to quickly and accurately detect submerged submarines. The sonobuoy pairs are dropped from a maritime patrol aircraft into the ocean in a predetermined pattern with a few buoys covering a very large area. The AN/SSQ110A Sonobuoy Series is an expendable and commandable sonobuoy. Upon command from the aircraft, the explosive charge would detonate, creating the sound impulse. Within the sonobuoy pattern, only one detonation is commanded at a time. Twelve to twenty SSQ110A source sonobuoys are used in a typical exercise. Both charges of each sonobuoy would be detonated independently during the course of the training, either tactically to locate the submarine, or when the sonobuoys are commanded to scuttle at the conclusion of the exercise. The AN/SSQ110A is listed in Table 1 because it functions like a sonar ping, however, the source creates an explosive detonation and its effects are considered in the underwater explosive section.

Advanced Extended Echo Ranging (AEER) SystemThe proposed AEER system is operationally similar to the existing EER/IEER system. The AEER system will use the same ADAR sonobuoy (SSQ101A) as the acoustic receiver and will be used for a large area ASW search capability in both shallow and deep water. However, instead of using an explosive AN/ SQS110A as an impulsive source for the active acoustic wave, the AEER system will use a battery powered (electronic) source for the AN/SSQ 125 sonobuoy. The output and operational parameters for the AN/SSQ125 sonobuoy (source levels, frequency, wave forms, etc.) are classified. However, this sonobuoy is intended to replace the EER/IEER's use of explosives and is scheduled to enter the fleet in 2011. For purposes of analysis, replacement of the EER/IEER system by the AEER system will be assumed to occur at 25% per year as follows: 201125% replacement; 201250% replacement; 201375% replacement; 2014100% replacement with no further use of the EER/IEER system beginning in 2015 and beyond.

TorpedoesTorpedoes are the primary ASW weapon used by surface ships, aircraft, and submarines. The guidance systems of these weapons can be autonomous or electronically controlled from the launching platform through an attached wire. The autonomous guidance systems are acoustically based. They operate either passively, exploiting the emitted sound energy by the target, or actively, ensonifying the target and using the received echoes for guidance. The MK48 submarine launched torpedo was modeled for active sonar transmissions as a high frequency source during specified training activities within the MIRC. The use of the less powerful MK46 and MK54 torpedoes will also occur in the MIRC, however, their use was accounted for by modeling all torpedo use in MIRC as if they were MK48 torpedoes.

Portable Undersea Tracking RangeThe Portable Undersea Tracking Range (PUTR) would be developed to support ASW training in areas where the ocean depth is between 400 m and 3500 m. In MIRC it would likely be deployed in a TORPEX area or in W517. This system would temporarily instrument up to a 100 squarenautical mile or smaller areas on the seafloor, and would provide high fidelity crew feedback and scoring of crew performance during ASW training activities. No onshore [[Page 53802]]
construction would take place. Seven electronics packages, each approximately 3 ft long by 2 ft in diameter, would be temporarily installed on the seafloor by a range boat. The anchors used to keep the electronics packages on the seafloor are made of steel, approximately 1.5 ftby1.5 ft and 300 pounds. PUTR use is planned for Navy training areas other than MIRC including the Northwest Training Range Complex and Gulf of Alaska. PUTR equipment can be recovered for maintenance or when training is completed. The Navy proposes to deploy this system year round, and to conduct TRACKEX and TORPEX activities for up to 35 days per year at any time of year. During each of the 35 days of annual operation, the PUTR would be in use for up to 8 hours each day. Two separate sound sources are associated with the operation of the PUTR:

Acoustic Device Countermeasures (ADCs)ADCs (e.g., AN/SLQ25 (``NIXIE''), MK2 and MK3 are, in effect, decoys to avert localization and/or torpedo attacks. These do not represent a significant source of sound given their intermittent use and operational characteristics (source output level and/or frequency). Given the sporadic use of these devices, the potential to affect marine mammals is unlikely, therefore these sources were not modeled or considered further in this analysis.

Training TargetsASW training targets are used to simulate opposition submarines. They are equipped with one or a combination of the following devices: (1) Acoustic projectors emanating sounds to simulate submarine acoustic signatures, (2) echo repeaters to simulate the characteristics of the echo of a particular sonar signal reflected from a specific type of submarine, and (3) magnetic sources to trigger magnetic detectors. Based on the operational characteristics (source output level and/or frequency) of these acoustic sources, the potential to affect marine mammals is unlikely, and therefore they were not modeled for this analysis.

SURTASS LFASURTASS LFA is a longrange, allweather, sonar system that operates in the low frequency band (100500 Hz). The system has both passive and active components. The active system component, LFA, is an augmentation to the passive detection system, and is planned for use when passive system performance proves inadequate. LFA is a set of acoustic transmitting source elements suspended by cable from underneath a ship. These elements, called projectors, are devices that produce the active sound pulse, or ping. The projectors transform electrical energy to mechanical energy that set up vibrations or pressure disturbances within the water to produce a ping. The passive, or listening, part of the system is SURTASS, which detects returning echoes from submerged objects, such as submarines, through the use of hydrophones. The SURTASS hydrophones are mounted on a receive array that is towed behind the vessel. The return signals or echoes, which are usually below background or ambient sound level, are then processed and evaluated to identify and classify potential underwater targets.

In the MIRC Study Area, the military intends to conduct three exercises (multistrike group exercises) that will include an LFA component during a fiveyear period that may include both SURTASS LFA and MFA active sonar sources. The expected duration of these combined exercises is approximately 14 days. Based on an exercise of this length, an LFA system would be active (i.e., actually transmitting) for no more than approximately 25 hours. In the combined exercise, LFA sonar is used as a longrange search tool (to find a potential target at long range) while MFA sonar is generally used as a closerrange search tool (to find a target at closer range). The LFA sonar and the MFA sonar would not normally be operated in close proximity to each other. Tactical and technical considerations dictate that the LFA ship would typically be tens of miles from the MFA ship when using active sonar.

Analysis of the environmental impacts of the SURTASS LFA system, including the potential for synergistic and cumulative effects with MFAS operation, was previously presented in a series of Navy EISs and the August, 2009 biological opinion for SURTASS LFA 2009 LOA, and the take of marine mammals incidental to the operation of LFA in the MIRC and elsewhere has been previously authorized by NOAA/NMFS (2002a, 2007). Although the authorization of take of marine mammals incidental to the operation of LFA sonar will not be considered here, NMFS describes and considers the limited manner in which the two separately analyzed systems (LFAS and MFAS) may interact in a multistrike group exercise in the MIRC.

Exercises Utilizing MFAS in the MIRC

As described above, ASW Exercises are the primary type of exercises that utilize MFAS and HFAS sources in the MIRC. Unit level tracking and torpedo ASW exercises occur regularly in the MIRC. Additionally, in a single year the MIRC will either have several major exercises, or one multistrike group exercise, that integrate ASW training with other types of training such as air, surface, or strike warfare. ASW exercise descriptions are included below and summarized (along with the exercises utilizing explosives) in Table 2.

ASW Tracking Exercise (TRACKEX)Generally, TRACKEXs train aircraft, ship, and submarine crews in tactics, techniques, and procedures for search, detection, localization, and tracking of submarines with the goal of determining a firing solution that could be used to launch a torpedo and destroy the submarine. ASW Tracking Exercises occur during both day and night. A typical unitlevel exercise involves one (1) ASW unit (aircraft, ship, or submarine) versus one (1) targeteither a MK39 Expendable Mobile ASW Training Target (EMATT), or a live submarine. The target may be nonevading while operating on a specified track or fully evasive. Participating units use active and passive sensors, including hullmounted sonar, towed arrays, and sonobuoys for tracking. If
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the exercise continues into the firing of a practice torpedo it is termed a Torpedo Exercise (TORPEX). The ASW TORPEX usually starts as a TRACKEX to achieve the firing solution. The different types of TORPEXs are further described below.

Torpedo Exercise (TORPEX)Antisubmarine Warfare (ASW) TORPEX activities train crews in tracking and attack of submerged targets, firing one or two exercise torpedoes (EXTORPs) or recoverable exercise torpedoes (REXTORPs). TORPEX targets and systems used in the Offshore Areas may include live submarines, MK46, MK54, and MK48 torpedoes, MK30 ASW training targets, and MK39 Expendable Mobile ASW Training Targets (EMATTs). The target may be nonevading while operating on a specified track, or it may be fully evasive, depending on the training requirements of the training exercise. Submarines periodically conduct torpedo firing training exercises within the MIRC. Typical duration of a submarine TORPEX exercise is 10 hours, while air and surface ASW platform TORPEX exercises using the MK46 and MK54 torpedoes are considerably shorter.

Joint Expeditionary ExerciseThe Joint Expeditionary Exercise brings different branches of the U.S. military together in a joint environment that includes planning and execution efforts as well as military operations at sea, in the air, and ashore. The purpose of the exercise is to train a U.S. Joint Task Force staff in crisis action planning for execution of contingency operations. It provides U.S. forces an opportunity to practice training together in a joint environment as well as a combined environment with partner nation forces, where more than 8,000 personnel may participate.

The participants and assets could include: Carrier Strike Group with its aircraft carrier, guided missile cruisers and Guided missile destroyers; Amphibious command and assault ships, submarines, logistic ships. It may also include Fleet and Battle Group Staffs, Naval and Air Force aircraft, Marine Expeditionary Units (MEU), and Army Infantry Units. This type of exercise would include activities conducted at sea and in the air and nearshore and ashore activities on Tinian, FDM, Guam, and Saipan.

ASW active sonar activity may include: Single and multiunit TRACKEX and TORPEX in coordinated ASW events; active ASW sources may include SQS53; SQS56; DICASS; IEER/AEER; AQS22; BQQ10; MK48 EXTORP; and, Portable Underwater Tracking Range operation including transponders and MK84 range tracking pingers.

Marine Air Ground Task Force (Amphibious) (MAGTF) ExerciseThis major exercise includes over the horizon, ship to objective maneuver and activities of the ESG and Amphibious MAGTF for up to 10 days. The exercise utilizes all elements of the MAGTF to secure the battlespace (air, land, and sea), maneuver to and seize the objective, and conduct selfsustaining operations ashore with continual logistic support of the ESG. Tinian is the primary MIRC training area for this exercise; however elements of the exercise may be rehearsed nearshore and on Guam.

ASW active sonar activity may include: single and multiunit TRACKEX and TORPEX in coordinated ASW event; active ASW sources may include SQS53C/D; SQS56; DICASS; IEER/AEER; AQS22; BQQ10; MK48 EXTORP and Portable Underwater Tracking Range operation including transponders and MK84 range tracking pingers.

Joint MultiStrike Group ExerciseThe Joint MultiStrike Group conducts training involving Navy assets engaging in a schedule of events (SOE) battle scenario, with U.S. forces pitted against a notional opposition force (OPFOR). Participants use and build upon previously gained training skill sets to maintain and improve the proficiency needed for a missioncapable, deploymentready unit.

The exercise includes several atsea activities. In Command and Control (C2), a command organization exercises operational control of the assets involved in the exercise. This control includes monitoring for safety and compliance with protective measures. Air Warfare (AW) includes missile exercises which involve firing live missiles at air targets. Ships and aircraft fire missiles against air targets. AW also includes nonfiring events such as Defensive Counter Air (DCA). DCA exercises ship and aircrew capabilities at detecting and reacting to incoming airborne threats. In AntiSurface Warfare (ASUW), Naval forces control sea lanes by countering hostile surface combatant ships.

ASW active sonar activity in this exercise may include: Single and multiunit TRACKEX and TORPEX in coordinated ASW events; active ASW sources may include SQS53C/D; SQS56; DICASS; IEER/AEER; AQS22; BQQ 10; MK48 EXTORP; Portable Underwater Tracking Range operation including transponders and MK84 range tracking pingers.
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Activities Utilizing Underwater Detonations

Underwater detonation activities can occur at various depths depending on the activity, but may also include activities with detonations at or just below the surface (such as SINKEX or gunnery exercise [GUNEX]). When the weapons hit the target, except for live torpedo shots, there is no explosion in the water, and so a ``hit'' is not modeled (i.e., the energy (either acoustic or pressure) from the hit is not expected to reach levels that would result in take of marine mammals). When a live weapon misses, it is modeled as exploding below the water surface at 1 ft (5inch naval gunfire, 76mm rounds), 2 meters (Maverick, Harpoon, MK82, MK83, MK84), or 50 ft (MK48 torpedo) as shown in Appendix A of the Navy's application (the depth is chosen to represent the worst case of the possible scenarios as related to potential marine mammals impacts). Exercises may utilize either live or inert ordnance of the types listed in Table 3. Additionally, successful hit rates are known to the Navy and are utilized in the effects modeling. Training events that involve explosives and underwater detonations occur throughout the year and are described below and summarized in Table 2.

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Sinking ExerciseIn a SINKEX, a specially prepared, deactivated vessel is deliberately sunk using multiple weapons systems. The exercise provides training to ship and aircraft crews in delivering both live and inert ordnance on a real target. These target vessels are empty, cleaned, and environmentallyremediated ship hulk. A SINKEX target is towed to sea and set adrift at the SINKEX location. The duration of a SINKEX is unpredictable since it ends when the target sinks, sometimes immediately after the first weapon impact and sometimes only after multiple impacts by a variety of weapons. Typically, the exercise lasts for 4 to 8 hours over 1 to 2 days. SINKEXs occur only occasionally during MIRC exercises. Potential harassment would be from underwater detonation. SINKEX events have been conducted in the open ocean of the western Pacific and within the MIRC, in compliance with 40 CFR 229.2.

The Environmental Protection Agency (EPA) grants the Navy a general permit through the Marine Protection, Research, and Sanctuaries Act to transport vessels ``for the purpose of sinking such vessels in ocean waters[hellip]'' (40 CFR 229.2). Subparagraph (a)(3) of this regulation states ``All such vessel sinkings shall be conducted in water at least 1,000 fathoms (6,000 feet) deep and at least 50 nautical miles from land.''

SINKEX events typically include at least one surface combatant (frigate, destroyer, or cruiser); one submarine; and numerous fixed wing and rotarywing aircraft. One surface ship will serve as a surveillance platform to ensure the hulk does not pose a hazard to navigation prior to and during the SINKEX. The weapons actually expended during a SINKEX can vary greatly. Table 12 in the Navy's application indicates the typical ordnance used in a SINKEX, which include HARPOON, HELLFIRE, and MAVERICK missiles, 5' gunfire, MK48 torpedoes, and underwater demolitions. This table reflects the planning for weapons, which may be expended during one SINKEX in the MIRC Study Area. This level of ordnance is expected for each of the SINKEX events in the Joint Multistrike Group exercise. With the exception of the torpedo, which is designed to explode below the target hulk in the water column, the weapons deployed during a SINKEX are intended to strike the target hulk, and thus not explode within the water column.

SurfacetoSurface Gunnery ExerciseSS GUNEX take place in the open ocean to provide gunnery practice for Navy and Coast Guard ship crews. GUNEX training activities conducted in the offshore study area involve stationary targets such as a MK42 floating atsea target (FAST) or a MK58 marker (smoke) buoy. The gun systems employed against surface targets include the 5inch, 76 millimeter (mm), 25mm chain gun, 20mm Closein Weapon System (CIWS), and 50caliber machine gun. Typical ordnance expenditure for a single GUNEX is a minimum of 21 rounds of 5inch or 76mm ammunition, and approximately 150 rounds of 25mm or .50caliber ammunition. Both live and inert training rounds are used. After impacting the water, the rounds and fragments sink to the bottom of the ocean. A GUNEX lasts approximately 1 to 2 hours, depending on target services and weather conditions. The live 5inch and 76mm rounds are considered in the underwater detonation modeling.

AirtoSurface Gunnery Exercise (AS GUNEX)AS GUNEX training activities are conducted by rotarywing aircraft against stationary targets (Floating atsea Target [FAST] and smoke buoy). Rotarywing aircraft involved in this activity would include a single helicopter using either 7.62mm or .50caliber doormounted machine guns. A typical GUNEX will last approximately one hour and involve the [[Page 53806]]
expenditure of approximately 400 rounds of 0.50caliber or 7.62mm ammunition. Due to their being inert and the small size of the rounds, they are not considered to have an underwater detonation impact.

AirtoSurface Missile Exercise (AS MISSILEX)The AS MISSILEX consists of the attacking platform releasing a forwardfired, guided weapon at the designated towed target. The exercise involves locating the target, then designating the target, usually with a laser. AS MISSILEX training that does not involve the release of a live weapon can take place if the attacking platform is carrying a captive air training missile (CATM) simulating the weapon involved in the training. The CATM MISSILEX is identical to a livefire exercise in every aspect except that a weapon is not released. The training requires a laser safe range as the target is designated just as in a livefire exercise. From 1 to 16 aircraft, carrying live, inert, or CATMs, or flying without ordnance (dry runs) are used during the exercise. At sea, seaborne powered targets (SEPTARs), Improved Surface Towed Targets (ISTTs), and decommissioned hulks are used as targets. AS MISSILEX assets include helicopters and/or 1 to 16 fixedwing aircraft with air tosurface missiles and antiradiation missiles (electromagnetic radiation source seeking missiles). Targets include SEPTARs, ISTTs, and excess ship hulks. When HELLFIRE Missiles are used the exercise is called a HELLFIRE MISSILEX. HELLFIRE MISSILEXs would occur 2 times per year in an area approximately 3035 nm south of Apra Harbor in W517. Potential harassment would be from underwater detonation.

SurfacetoSurface Missile Exercise (SS MISSILEX)SS MISSILEX involves the attack of surface targets at sea by use of cruise missiles or other missile systems, usually by a single ship conducting training in the detection, classification, tracking and engagement of a surface target. SS MISSILEXs always occur during a SINKEX. Engagement is usually with HARPOON missiles or Standard missiles in the surfaceto surface mode. Targets could include virtual targets or the SEPTAR or ship deployed surface target. SS MISSILEX training is routinely conducted on individual ships with embedded training devices. A SS MISSILEX could include 4 to 20 surfacetosurface missiles, SEPTARs, a weapons recovery boat, and a helicopter for environmental and photo evaluation. All missiles are equipped with instrumentation packages or a warhead. Surfacetoair missiles can also be used in a surfaceto surface mode. Each exercise typically lasts five hours. Future SS MISSILEX could range from 4 to 35 hours. Potential harassment would be from underwater detonation.

AirtoSurface Bombing ExerciseDuring an AirtoSurface Bombing Exercise (BOMBEX AS), fixedwing aircraft deliver bombs against simulated surface maritime targets, typically a smoke float, with the goal of destroying or disabling enemy ships or boats. Typically, a flight of two aircraft will approach the target from an altitude of between 15,000 ft to less than 3,000 ft, and will adhere to designated ingress and egress routes. Typical bomb release altitude is below 3,000 ft and within a range of 1000 yards for unguided munitions, and above 15,000 ft and in excess of 10 nm for precisionguided munitions. In most training exercises, the aircrew drops inert training ordnance, such as the Bomb Dummy Unit (BDU45) on a MK58 smoke float used as the target. Some BOMBEXs include the use of the MK84/GBU31 JDAM, the largest bomb proposed for use. JDAM training would occur 4 times per year in W517 and generally in the southern portion avoiding known fishing areas. The surface danger zone requires a 25 nm buffer around the aim point, so that all operations occur within W517. Each BOMBEX AS can take up to 4 hours to complete.

Mine NeutralizationMine Neutralization involves the detection, identification, evaluation, rendering safe, and disposal of mines and unexploded ordnance (UXO) that constitutes a threat to ships or personnel. Mine neutralization training can be conducted by a variety of air, surface and undersea assets. Potential harassment would be from underwater detonation.

Tactics for neutralization of ground or bottom mines involve the diver placing a specific amount of explosives, which when detonated underwater at a specific distance from a mine results in neutralization of the mine. Floating, or moored, mines involve the diver placing a specific amount of explosives directly on the mine. Floating mines encountered by Fleet ships in openocean areas are detonated at the surface. In support of an expeditionary assault, divers and Navy marine mammal assets deploy in very shallow water depths (10 to 40 feet) to locate mines and obstructions. Divers are transported to the mines by boat or helicopter. Inert dummy mines are used in the exercises. The total net explosive weight used against each mine ranges from less than 1 pound to 20 pounds.

All demolition activities are conducted in accordance with Commander, Naval Surface Forces Pacific (COMNAVSURFPAC) Instruction 3120.8F, Procedures for Disposal of Explosives at Sea/Firing of Depth Charges and Other Underwater Ordnance (DoN 2003). Before any explosive is detonated, divers are transported a safe distance away from the explosive. Standard practices for tethered mines require ground mine explosive charges to be suspended 10 feet below the surface of the water.

EERIEER AN/SSQ110AThe Extended Echo Ranging and Improved Extended Echo Ranging (EER/IEER) Systems are airborne ASW systems used in conducting ``large area'' searches for submarines. These systems are made up of airborne avionics ASW acoustic processing and sonobuoy types that are deployed in pairs. The IEER System's active sonobuoy component, the AN/SSQ110A Sonobuoy, generates a sound similar to a ``sonar ping'' using a small explosive and the passive AN/SSQ101A ADAR Sonobuoy ``listens'' for the return echo of the ``sonar ping'' that has been bounced off the surface of a submarine. These sonobuoys are designed to provide underwater acoustic data necessary for naval aircrews to quickly and accurately detect submerged submarines. The sonobuoy pairs are dropped from a fixedwing aircraft into the ocean in a predetermined pattern with a few buoys covering a very large area. The AN/SSQ110A Sonobuoy Series is an expendable and commandable sonobuoy. Upon command from the aircraft, the bottom payload is released to sink to a designated operating depth. A second command is required from the aircraft to cause the second payload to release and detonate the explosive to generate a ``ping''. There is only one detonation in the pattern of buoys at a time. Potential harassment would be from underwater detonations.

The AEER system (described in the sonar source section) will eventually replace use of the EER/IEER system and was analyzed for this proposed rule.

Vessel Movement

The operation and movement of vessels that is necessary to conduct the training described above is also analyzed here. Training exercises involving vessel movements occur intermittently and are variable in duration, ranging from a few hours up to 10 days. During training, speeds vary and depend on the specific type of activity, although 1014 knots is considered the typical speed. The Navy logs about 1,000 total vessel days within
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the MIRC Study Area during a typical year. Training activities are widely dispersed throughout the large OPAREA, which encompasses 501,873 nm\2\ (1,299,851 km\2\). Consequently, the density of Navy ships within the Study Area at any given time is low.

Research, Development, Testing, and Evaluation

The Services may conduct RDT&E, engineering, and fleet support for command, control, and communications systems and ocean surveillance in the MIRC. These activities may include ocean engineering, missile firings, torpedo testing, manned and unmanned submersibles testing, unmanned aerial vehicle (UAV) tests, electronic combat (EC), and other DoD weapons testing.

RDT&E activities, if they have a potential for takes of marine mammals, will be reviewed to assure they are included within the parameters of existing sonar and explosive activities as modeled for this rule and the LOAs. As an example, if a new model of SQS 53 sonar were tested, as long as it's operating parameters are within the parameters modeled, an equal number of hours of SQS 53C use in training would be deducted to ensure that the total SQS 53C hours for the year (training plus RDT&E) remain within those described in the rule. The same would apply for explosives, overall NET explosive weights for similar munitions would be reviewed to assure compliance with existing rules.

Additional information on the Navy's proposed activities may be found in the LOA Application and the Navy's MIRC DEIS.
Description of Marine Mammals in the Area of the Specified Activities

Thirtytwo marine mammal species or populations/stocks have confirmed or possible occurrence within the MIRC, including seven species of baleen whales (mysticetes), 22 species of toothed whales (odontocetes), two species of seal (pinnipeds), and the dugong (sirenian). Table 4 summarizes their abundance, Endangered Species Act (ESA) status, occurrence, and density in the area. Seven of the species are ESAlisted and considered depleted under the MMPA: Blue whale; fin whale; humpback whale; sei whale; sperm whale; North Pacific right whale; Hawaiian monk seal; and dugong. The dugong is managed by the U.S. Fish and Wildlife Service and will not be addressed further here. BILLING CODE 351022P
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BILLING CODE 351022C

Species Not Considered Further

North Pacific right whaleThe likelihood of a North Pacific right whale (Eubalaena japonica) occurring in the action area is extremely low. The North Pacific right whale population is the most endangered of the large whale species (Perry et al., 1999) and, currently, there is no reliable population estimate for this species, although the population in the western North Pacific Ocean is considered to be very small, perhaps in the tens to low hundreds of animals. Despite many years of systematic aerial and shipbased surveys for marine mammals off the western coast of the U.S., only seven documented sightings of right whales were made from 1990 through 2005 near Alaska (Waite et al., 2003; Wade et al., 2006). Based on this information, it is highly unlikely for a right whale to be present in the action area. Consequently, this species will not be considered in the remainder of this analysis.

Hawaiian monk sealThe likelihood of a Hawaiian monk seal (Monachus schauinslandi) being present in the action area is extremely low. There are no confirmed records of Hawaiian monk seals in the Micronesia region; however, Reeves et al. (1999) and Eldredge (1991, 2003) have noted occurrence records for
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seals (unidentified species) in the Marshall and Gilbert islands. It is possible that Hawaiian monk seals wander from the Hawaiian Islands to appear at the Marshall or Gilbert Islands in the Micronesia region (Eldredge 1991). However, given the extremely low likelihood of this species occurrence in the action area, the Hawaiian monk seal will not be considered in the remainder of this analysis.

Hubbs Beaked WhaleThe likelihood of a Hubbs beaked whale (Mesoplodon carlhubbsi) occurring in the action area is extremely low. There are no occurrence records for the Mariana Islands and the nearest records are from strandings in Japan (DoN 2005). Recent data suggests that the distribution is likely north of 30[deg] N (MacCleod et al., 2006). Given the extremely low likelihood of this species occurrence in the action area, the Hubbs beaked whale will not be considered in the remainder of this analysis.

IndoPacific Bottlenose DolphinThe likelihood of an IndoPacific bottlenose dolphin (Tursiops aduncas) occurring in the action area is extremely low. The IndoPacific bottlenose dolphin is generally associated with continental margins and does not appear to occur around offshore islands that are great distances from a continent, such as the Marianas (Jefferson as cited in DoN 2005). Given the extremely low likelihood of this species occurrence in the action area, the Indo Pacific bottlenose dolphin will not be considered in the remainder of this analysis.

Northern Elephant SealNorthern elephant seals (Mirounga angustirostris) are common on islands and mainland haulout sites in Baja California, Mexico north through central California. Elephant seals spend several months at sea feeding and travel as far as the Gulf of Alaska. Occasionally juveniles wander great distances with several individuals being observed in Hawaii and Japan. Although elephant seals may wander great distances it is very unlikely that they would travel to Japan or Hawaii and then continue traveling to the MIRC. Given the extremely low likelihood of this species occurrence in the action area, the northern elephant seal will not be considered in the remainder of this analysis.

The Navy has compiled information on the abundance, behavior, status and distribution, and vocalizations of marine mammal species in the MIRC waters from the Navy Marine Resource Assessment and has supplemented this information with additional citations derived from new survey efforts and scientific publications. NMFS has not designated stocks of marine mammals in the waters surrounding the MIRC and, therefore, does not compile stock assessment reports for this area. This information may be viewed in the Navy's LOA application and/or the Navy's DEIS for MIRC (see Availability), and is incorporated by reference herein.

There are no designated marine mammal critical habitats or known breeding areas within the MIRC. Much is unknown about the reproductive habits of the dolphin species in MIRC, but they are thought to mate throughout their range (like better studied species and stocks are known to do) and possibly throughout the year. Even less is known about the mating habits of beaked whales. Baleen whales and sperm whales are thought to breed seasonally in areas within and around the MIRC and some calves have been seen with sperm, Bryde's and sei whales (DoN 2007b), although it is not known where exactly breeding and calving occurs.

Spinner dolphins, which rest primarily during the day in relatively large groups, are known to consistently use certain areas (usually bays) for this function. Because of this, they are regularly visited by whalewatching boats or other members of the public interested in viewing or interacting with them, which could potentially put them at increased energetic risk if their resting cycles are repeatedly interrupted in a significant manner. There are several recognized resting areas for spinner dolphins in the MIRC Study Area: Agat Bay, Bile/Tougan Bay, and Double Reef. These areas are in clear, calm, shallow waters sheltered from prevailing tradewinds.

Marine Mammal Hearing and Vocalizations

Cetaceans have an auditory anatomy that follows the basic mammalian pattern, with some changes to adapt to the demands of hearing in the sea. The typical mammalian ear is divided into an outer ear, middle ear, and inner ear. The outer ear is separated from the inner ear by a tympanic membrane, or eardrum. In terrestrial mammals, the outer ear, eardrum, and middle ear transmit airborne sound to the inner ear, where the sound waves are propagated through the cochlear fluid. Since the impedance of water is close to that of the tissues of a cetacean, the outer ear is not required to transduce sound energy as it does when sound waves travel from air to fluid (inner ear). Sound waves traveling through the inner ear cause the basilar membrane to vibrate. Specialized cells, called hair cells, respond to the vibration and produce nerve pulses that are transmitted to the central nervous system. Acoustic energy causes the basilar membrane in the cochlea to vibrate. Sensory cells at different positions along the basilar membrane are excited by different frequencies of sound (Pickles, 1998). Baleen whales have inner ears that appear to be specialized for low frequency hearing. Conversely, dolphins and porpoises have ears that are specialized to hear high frequencies.

Marine mammal vocalizations often extend both above and below the range of human hearing; vocalizations with frequencies lower than 18 Hertz (Hz) are labeled as infrasonic and those higher than 20 kHz as ultrasonic (National Research Council [NRC], 2003; Figure 41). Measured data on the hearing abilities of cetaceans are sparse, particularly for the larger cetaceans such as the baleen whales. The auditory thresholds of some of the smaller odontocetes have been determined in captivity. It is generally believed that cetaceans should at least be sensitive to the frequencies of their own vocalizations. Comparisons of the anatomy of cetacean inner ears and models of the structural properties and the response to vibrations of the ear's components in different species provide an indication of likely sensitivity to various sound frequencies. The ears of small toothed whales are optimized for receiving highfrequency sound, while baleen whale inner ears are best in low to infrasonic frequencies (Ketten, 1992; 1997; 1998).

Baleen whale vocalizations are composed primarily of frequencies below 1 kHz, and some contain fundamental frequencies as low as 16 Hz (Watkins et al., 1987; Richardson et al., 1995; Rivers, 1997; Moore et al., 1998; Stafford et al., 1999; Wartzok and Ketten, 1999) but can be as high as 24 kHz (humpback whale; Au et al., 2006). Clark and Ellison (2004) suggested that baleen whales use low frequency sounds not only for longrange communication, but also as a simple form of echo ranging, using echoes to navigate and orient relative to physical features of the ocean. Information on auditory function in mysticetes is extremely lacking. Sensitivity to lowfrequency sound by baleen whales has

FOR FURTHER INFORMATION CONTACT

Jolie Harrison, Office of Protected Resources, NMFS, (301) 7132289, ext. 166.