# Taking and Importing Marine Mammals; U.S. Navy Training in the Hawaii Range Complex > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A08-1371 ## Record - **Collection:** Federal Register - **Document type:** Proposed Rule - **Published:** June 23, 2008 - **Citation:** 73 FR 35510 ## Text DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration 50 CFR Part 216 [Docket No. 080519680-8684-01] RIN 0648-AW86 Taking and Importing Marine Mammals; U.S. Navy Training in the Hawaii Range Complex AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce. ACTION: Proposed rule; request for comments. SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for authorization to take marine mammals incidental to training activities conducted within the Hawaii Range Complex (HRC) for the period of December 2008 through December 2013. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is proposing regulations to govern that take and requesting information, suggestions, and comments on these proposed regulations. DATES: Comments and information must be received no later than July 23, 2008. ADDRESSES: You may submit comments, identified by 0648-AW86, by any one of the following methods: • Electronic Submissions: Submit all electronic public comments via the Federal eRulemaking Portal: http://www.regulations.gov . • Hand delivery or mailing of paper, disk, or CD-ROM comments should be addressed to Michael Payne, Chief, Permits, Conservation and Education Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225. Instructions: All comments received are a part of the public record and will generally be posted to http://www.regulations.gov without change. All Personal Identifying Information (for example, name, address, etc.) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business Information or otherwise sensitive or protected information. NMFS will accept anonymous comments. Attachments to electronic comments will be accepted in Microsoft Word, Excel, WordPerfect, or Adobe PDF file formats only. Comments regarding the burden-hour estimates or other aspects of the collection-of-information requirements contained in this proposed rule should be submitted in writing to Michael Payne at the address above and to David Rostker, OMB, by e-mail at David_Rostker@omb.eop.gov or by fax to 202-395-7285. FOR FURTHER INFORMATION CONTACT: Jolie Harrison, Office of Protected Resources, NMFS, (301) 713-2289, ext. 166. SUPPLEMENTARY INFORMATION: Availability A copy of the Navy's application may be obtained by writing to the address specified above (See ADDRESSES ), telephoning the contact listed above (see FOR FURTHER INFORMATION CONTACT ), or visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm . The Navy's Final Environmental Impact Statement (FEIS) for the Hawaii Range Complex was published on May 9, 2008, and may be viewed at http://www.govsupport.us/hrc . NMFS participated in the development of the Navy's FEIS as a cooperating agency under NEPA. Last, NMFS is preparing a Draft Environmental Assessment (EA) that analyzes the environmental effects of several different mitigation alternatives for the potential issuance of the proposed rule. The Draft EA will be posted on the following Web site as soon as it is complete: http://www.nmfs.noaa.gov/pr/permits/incidental.htm . Background Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq. ) direct the Secretary of Commerce (Secretary) to allow, upon request, the incidental, but not intentional taking of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) during periods of not more than five consecutive years each if certain findings are made and regulations are issued or, if the taking is limited to harassment, notice of a proposed authorization is provided to the public for review. Authorization shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses, and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such taking are set forth. NMFS has defined “negligible impact” in 50 CFR 216.103 as: An impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival. The National Defense Authorization Act of 2004 (NDAA) (Public Law 108-136) removed the “small numbers” and “specified geographical region” limitations and amended the definition of “harassment” as it applies to a “military readiness activity” to read as follows (Section 3(18)(B) of the MMPA): (i) Any act that injures or has the significant potential to injure a marine mammal or marine mammal stock in the wild [Level A Harassment]; or (ii) Any act that disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly altered [Level B Harassment]. Summary of Request On June 25, 2007, NMFS received an application from the Navy requesting authorization for the take of 24 species of marine mammals incidental to upcoming Navy training activities to be conducted within the HRC, which covers 235,000 nm 2 around the Main Hawaiian Islands (see map on page 17 of the application), over the course of 5 years. These training activities are classified as military readiness activities. The Navy states that these training activities may incidentally take marine mammals present within the HRC by exposing them to sound from mid-frequency or high frequency active sonar (MFAS/HFAS) or to underwater detonations at levels that NMFS associates with the take of marine mammals. The Navy requests authorization to take individuals of 24 species of marine mammals by Level B Harassment. Further, though they do not anticipate it to occur, the Navy requests authorization to take, by injury or mortality, up to 10 individuals each of 10 species over the course of the 5-year period (bottlenose dolphin, Kogia spp. , melon-headed whale, pantropical spotted dolphin, pygmy killer whale, short-finned pilot whale, striped dolphin, and Cuvier's, Longman's, and Blainville's beaked whale). Background of Navy Request The Navy's mission is to maintain, train, and equip combat-ready naval forces capable of winning wars, deterring aggression, and maintaining freedom of the seas. Title 10, U.S. Code (U.S.C.) section 5062 directs the Chief of Naval Operations to train all naval forces for combat. The Chief of Naval Operations meets that direction, in part, by conducting at-sea training exercises and ensuring naval forces have access to ranges, operating areas (OPAREAs) and airspace where they can develop and maintain skills for wartime missions and conduct research, development, test, and evaluation (RDT&E) of naval weapons systems. The HRC, where the Navy has, for more than 40 years, routinely conducted training and major exercises in the waters around the Hawaiian Islands, is a critical part of the Navy's mission, especially as it relates to training, for several reasons. Centrally located in the Pacific Ocean between the west coast of the United States and the naval stations in the western Pacific, and surrounding the most isolated islands in the world, the HRC has the infrastructure (i.e., extensive existing range assets and training capabilities) to support a large number of forces in a location both remote and under U.S. control. The range surrounds the major homeport of Naval Station Pearl Harbor, enabling re-supply and repairs to submarines and surface ships alike. The isolation of the range offers an invaluable facility on which to conduct missile testing and training. Able to link with the U.S. Army's Pohakuloa Training Area, as well as U.S. Air Force and U.S. Marine Corps bases where aircraft basing and amphibious training may occur, the HRC provides a superior joint training environment for all the U.S. armed services and advanced missile testing capability. Among the important assets of the HRC is the Pacific Missile Range Facility (PMRF), which is the world's largest instrumented, multi-environment, military test range capable of supporting subsurface, surface, air, and space training, and RDT&E. It consists of instrumented underwater ranges, controlled airspace, and a temporary operating area covering 2.1 million square nautical miles (nm 2 ) of ocean area. The Navy must have the flexibility and capacity to quickly surge required combat power in the event of a national crisis or contingency operation. Because of its location, training for sustained deployment at the HRC, rather than at ranges on the west coast, saves 10 transit days to the western Pacific from the west coast of the United States. The HRC complex consists of targets and instrumented areas, airspace, surface OPAREAS, and land range facilities. The Navy's proposed action includes conducting current and emerging training in the HRC. Although the Navy plans to conduct many different types of RDT&E on the land, in the air, and in the water, as well as implement infrastructure improvements (addressed comprehensively in the Navy's FEIS), this document specifically analyzes those activities in the HRC for which the Navy seeks MMPA incidental take authorization, i.e., those training activities that the Navy predicts would result in the generation of levels of sound in the water that NMFS has indicated are likely to result in the take of marine mammals (not counting SURTASS LFA sonar, for which the Navy has already obtained an MMPA authorization), either through the use of sonar (mid-frequency active sonar (MFAS) or high frequency active sonar (HFAS)) or from the use of live ordnance, including the detonation of explosives in the water. Table 1-1 in the Navy's application presents a summary of the training and RDT&E activities that will occur in the HRC and indicates the exercise types that the Navy's modeling indicated would likely result in the take of marine mammals. Description of the Specified Activities As mentioned above, the Navy has requested MMPA authorization to take marine mammals incidental to training activities in the HRC that would result in the generation of sound 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. Activities Utilizing Active Tactical Sonar Sources For this operating area (HRC), the training activities that utilize active tactical sonar sources fall into the category of Anti-submarine Warfare (ASW) exercises. This section includes a description of the active acoustic devices used in ASW exercises, as well as the exercise types in which these acoustic sources are used. Acoustic Sources Used for ASW Exercises in the HRC Tactical military sonars are designed to search for, detect, localize, classify, and track submarines. There are two types of sonars, passive and active: • Passive sonars only listen to incoming sounds and, since they do not emit sound energy in the water, lack the potential to acoustically affect the environment. • Active sonars generate and emit acoustic energy specifically for the purpose of obtaining information concerning a distant object from the received and processed reflected sound energy. Modern sonar technology includes a multitude of sonar sensor and processing systems. In concept, the simplest active sonars emit omni-directional pulses (“pings”) and time the arrival of the reflected echoes from the target object to determine range. More sophisticated active sonar emits an omni-directional ping and then rapidly scans a steered receiving beam to provide directional, as well as range, information. More advanced sonars transmit multiple preformed beams, listening to echoes from several directions simultaneously and providing efficient detection of both direction and range. The tactical military sonars to be deployed during testing and training in the HRC are designed to detect submarines in tactical training scenarios. This task requires the use of the sonar mid-frequency range (1 kilohertz [kHz] to 10 kHz) predominantly, as well as one source in the high frequency range (above 10 kHz) that operates at a level high enough to be considered in the modeling. The high frequency source will contribute a comparatively very small amount to the total amount of active sonar that marine mammals will be exposed to during the Navy's proposed activities, however, for this document we will refer to the collective high and mid-frequency sonar sources as MFAS/HFAS. A narrative description of the types of acoustic sources used in ASW training exercises is included below. Table 1 (below) summarizes the nominal characteristics of the acoustic sources used in the modeling to predict take of marine mammals. EP23JN08.001 Surface Ship Sonars —A variety of surface ships participate in testing and training events. Some ships (e.g., aircraft carriers, amphibious assault ships) do not have any onboard active sonar systems, other than fathometers. Others, like guided missile cruisers, are equipped with active as well as passive tactical sonars for mine avoidance and submarine detection and tracking. Within Navy ASW exercises in the HRC, two types of hull-mounted sonar sources account for the majority of the estimated impacts to marine mammals. The AN/SQS-53 hull-mounted sonar, which has a nominal source level of 235 decibels (dB) re 1 μPa and transmits at center frequencies of 2.6 kHz and 3.3 kHz, is the Navy's most powerful sonar source used in ASW exercises in the HRC. The AN/SQS-56 hull-mounted sonar has a nominal source level of 225 dB re 1 μPa and transmits at a center frequency of 7.5 kHz. Sonar ping transmission durations were modeled as lasting 1 second per ping and omni-directional, which is a conservative assumption that may overestimate potential effects. Actual ping durations will be less than 1 second. 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. The AN/SQS-53 and the AN/SQS-56 were modeled using the number of hours of predicted use (typically at two pings per minute; meaning an hour of sonar operation results in approximately 120 one-second pings). Based on modeling results, the Navy anticipates that the operation of these two sources will likely result in take of marine mammals (see Estimated Take of Marine Mammals Section). Hull-mounted sonars occasionally operate in a mode called “Kingfisher,” which is designed to better detect smaller objects. The Kingfisher mode uses the same source level and frequency as normal search modes, however, it uses a different waveform (designed for small objects), a shorter pulse length (< 1 sec), a higher pulse repetition rate (due to the short ranges), and the ping is not omnidirectional, but directed forward. All Kingfisher use in the HRC (approximately 27 hours/year) was modeled as AN/SQS-53, though the less powerful AN/SQS-56 likely accounts for part of the total Kingfisher use as well. Submarine Sonars —Submarine sonars (AN/BQQ-10, AN/BQQ-5, or AN/BSY-1) are used to detect and target enemy submarines and surface ships. Because they are trying to avoid being detected, a submarine's use of MFAS is generally rare, very brief, using minimal power, and may be narrowly focused. Modeling for the AN/BQQ-10 (all three submarine types were modeled as AN/BQQ-10, the most powerful submarine sonar source) assumes sonar use of two pings an hour (which is higher than typical), for one second each, at 235 dB re 1 μPa, and using an omni-directional transmission. The AN/BQQ-10 was modeled using the number of hours of predicted use (at two pings per hour). Based on modeling results, the Navy anticipates that the operation of this source may result in some take of marine mammals (see Estimated Take of Marine Mammals Section). Aircraft Sonar Systems —Aircraft sonar systems that would operate in the HRC include sonobuoys (SSQ-62) and dipping sonar (AN/AQS-22). A sonobuoy is an expendable device, which may be deployed by maritime patrol aircraft or helicopters, used for the detection of underwater acoustic energy and for conducting vertical water column temperature measurements. Most sonobuoys are passive, but some, like the SSQ-62, can also generate active acoustic signals. The SSQ-62 has a nominal source level of 201 dB re 1 μPa and transmits at a center frequency of 8 kHz. Dipping sonar is an active or passive sonar device lowered on cable 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. The AN/AQS-22 has a nominal source level of 217 dB re 1 μPa and transmits at a center frequency of 4.1 kHz. Based on modeling results, the Navy anticipates that the operation of these two sources may result in some take of marine mammals (see Estimated Take of Marine Mammals Section). Torpedoes —Torpedoes are the primary ASW weapon used by surface ships, aircraft, and submarines. The guidance systems of these weapons can be autonomous (acoustically based) or electronically controlled from the launching platform through an attached wire. They operate either passively, exploiting the emitted sound energy by the target, or actively, ensonifying the target and using the received echoes for guidance. We know that the MK-48 operates in the high frequency range (>10 kHZ), however, the nominal source level and the center frequency are classified. Based on modeling results, the Navy anticipates that the operation of this source may result in some take of marine mammals (see Estimated Take of Marine Mammals Section). In addition to the HFA sonar source used to guide the torpedo, the MK-48 is discussed in the “Activities Utilizing Underwater Detonations” Section. Other Acoustic Sources —The Navy uses other acoustic sources in ASW exercises. However, based on operational characteristics (such as frequency and source level), the Navy determined that use of the following acoustic sources would not likely result in the take of marine mammals: • Acoustic Device Countermeasures (ADC)—submarine simulators that make sound to act as decoys to avert localization and/or torpedo attacks. • Training Targets—ASW training targets consisting of MK-30 and/or MK-39 Expendable Mobile ASW Training Target (EMATT) 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. • Range pingers are active acoustic devices that allow inwater platforms on the range (e.g., submarines, target simulators, and exercise torpedoes) to be tracked by hydrophones on the seafloor such as those at the underwater instrumented range at PMRF. The range hydrophones are also tied in with transducer nodes that are capable of transmitting acoustic signals for a limited set of functions, including submarine warning signals, acoustic commands to submarine target simulators (acoustic command link), and occasional voice or data communications (received by participating ships and submarines on range). Types of ASW Exercises in the HRC ASW training conducted within the HRC involves the use of surface ships, submarines, aircraft, non-explosive and explosive exercise weapons, and other training-related devices. ASW training involves the use of active and passive acoustic devices with training activities occurring in both offshore (<12 nm (22 km) from shore) and open ocean (>12 nm (22 km) from shore) areas. A description of the different exercise types is provided below. Table 2 lists the types of ASW exercises and indicates the areas they are conducted in, the average duration of an exercise, the average number of exercises/per year, and the time of year they are conducted. Table 3, at the end of this section, indicates the total number of hours for each source type anticipated for each year for each exercise type. EP23JN08.002 Anti-Submarine Warfare Tracking Exercise (ASW TRACKEX) —An ASW TRACKEX trains aircraft, ship, and submarine crews in tactics, techniques, and procedures for search, detection, and tracking of submarines. No torpedoes are fired during a TRACKEX. ASW TRACKEX includes ships, fixed wing aircraft, helicopters, torpedo targets, submarines, and weapons recovery boats and/or helicopters. As a unit-level exercise, an aircraft, ship, or submarine is typically used versus one target submarine or simulated target. TRACKEXs can include the use of hull-mounted sonar, submarines, or sonobuoys. No explosive ordnance is used in TRACKEX exercises. The target may be non-evading while operating on a specified track or it may be fully evasive, depending on the state of training of the ASW unit. Duration of a TRACKEX is highly dependent on the tracking platform and its available on-station time. A maritime patrol aircraft can remain on station for eight hours, and typically conducts tracking exercises that last three to six hours. An ASW helicopter has a much shorter on-station time, and conducts a typical TRACKEX in one to two hours. Surface ships and submarines, which measure their on-station time in days, conduct tracking exercises exceeding eight hours and averaging up to 18 hours. For modeling purposes, TRACKEX and TORPEX (explained in next section) sonar hours are averaged, resulting in a sonar time of 13.5 hours. ASW TRACKEX events are conducted on ranges within PMRF Warning Area W-188, the Hawaii Offshore Areas and/or the open ocean. Whenever aircraft use the ranges for ASW training, range clearance procedures include a detailed visual range search for marine mammals and unauthorized boats and planes by the aircraft releasing the inert torpedoes, range safety boats/aircraft, and range controllers. TRACKEXs can include the use of hull-mounted sonar, submarines, or sonobuoys, which can result in the take of marine mammals. Anti-Submarine Warfare Torpedo Exercises (ASW TORPEX) —Anti-Submarine Warfare Torpedo Exercises (ASW TORPEX) train crews in tracking and attack of submerged targets, firing one or more Recoverable Exercise Torpedoes. TORPEX targets used in the Offshore Areas include submarines, MK-30 ASW training targets, and MK-39 Expendable Mobile ASW Training Targets. The target may be non-evading while operating on a specified track, or it may be fully evasive, depending on the training requirements. Submarines periodically conduct torpedo firing training exercises within the Hawaii Offshore OPAREA. Typical duration of a submarine TORPEX event is 22.7 hours, while air and surface ASW platform TORPEX events are considerably shorter. For modeling purposes, TRACKEX and TORPEX sonar hours are averaged resulting in a sonar time of 13.5 hours. TORPEXs can include the use of hull-mounted sonar, submarines, sonobuoys, or MK-48 torpedoes (inert), which can result in the take of marine mammals. Rim of the Pacific (RIMPAC) —RIMPAC is a multi-threat maritime exercise where submarines, surface ships, and aircraft from the U.S. and other countries conduct many different exercise events, including ASW against opposition submarine targets to improve coordination and interoperability of combined, bilateral and joint forces of participating nations. RIMPAC occurs during the summer over a 1-month period every other year (currently in even numbered years). Submarine targets include real submarines, targets that simulate the operations of an actual submarine including those described previously under TORPEX, and virtual submarines interjected into the training events by exercise controllers. ASW training events are complex and highly variable. For RIMPAC, the primary event involves a Surface Action Group (SAG), consisting of one to five surface ships equipped with sonar, with one or more helicopters, and a P-3 aircraft searching for one or more submarines. There will be approximately four to eight SAGs for a typical RIMPAC. For the purposes of analysis, each SAG event is counted as an ASW training activity. One or more ASW events may occur simultaneously within the HRC. There will be approximately 44 ASW training events during a typical RIMPAC, with an average event length of approximately 12 hours (ranging from 2-24 hours). In addition to including potential training with of all of the acoustic sources mentioned previously, RIMPAC includes training events that involve underwater detonations (described in the next section: Activities Utilizing Underwater Detonations), including Sinking Exercise, Air-to-Surface Gunnery Exercise, Surface-to-Surface Gunnery Exercise, Naval Surface Fire Support, Air-to-Surface Missile Exercise, Surface-to-Surface Missile Exercise, Bombing Exercise, Mine Neutralization Exercise, and IEER/EER Exercise. Both the use of the acoustic sources as well as the underwater detonations could result in the take of marine mammals. These exercises involving underwater detonations do not overlap in space and time with sonar exercises. Explosives from RIMPAC have been included in the training events described in the next Section. Undersea Warfare Exercise (USWEX) —Carrier Strike Groups (CSGs) and Expeditionary Strike Groups (ESGs) that deploy from the west coast of the United States will experience realistic submarine combat conditions and assess submarine warfare training capabilities postures in the HRC prior to their deployment to real world operations elsewhere. As a combined force, submarines, surface ships, and aircraft will conduct ASW against opposition submarine targets, which include real submarines, targets that simulate the operations of an actual submarine, and virtual submarines interjected into the training events by exercise controllers. USWEX training events are complex and highly variable. The primary event involves from one to five surface ships equipped with sonar, with one or more helicopters, and a P-3 aircraft searching for one or more submarines. A total of five exercises using MFAS/HFAS, lasting three to four days each, could occur throughout the year for USWEX. In addition to the use of hull-mounted sonar (AN/SQS-53 and AN/SQS-56), submarine sonar, helicopter dipping sonar, and sonobuoys, USWEX includes training events that involve underwater detonations as described in the next section (Activities Utilizing Underwater Detonations), including Air-to-Surface Gunnery Exercise, Air-to-Surface Missile Exercise, and Bombing Exercise. Both the use of the acoustic sources as well as the underwater detonations could result in the take of marine mammals. These exercises utilizing underwater detonations do not overlap in space and time with sonar exercises. Explosives from USWEX have been included in the training events described in the next section. Multiple Strike Group Exercise —A Multiple Strike Group Exercise consists of events that involve Navy assets engaging in a schedule of events battle scenario, with U.S. forces (blue forces) pitted against a notional opposition force (red force). Participants use and build upon previously gained training skill sets to maintain and improve the proficiency needed for a mission-capable, deployment-ready unit. The exercise would occur over a 5-day to 10-day period at any time during the year. As described above for USWEX, as a combined force, submarines, surface ships, and aircraft will conduct ASW against opposition submarine targets. In addition to the use of hull-mounted sonar (AN/SQS-53 and AN/SQS-56), submarine sonar, helicopter dipping sonar, and sonobuoys , the Multiple Strike Group Exercise includes training events that involve underwater detonations as described in the next Section (Activities Utilizing Underwater Detonations), including Sinking Exercise, Air-to-Surface Missile Exercise, Mine Neutralization Exercise, and EER/IEER Exercise. Both the use of the acoustic sources as well as the underwater detonations could result in the take of marine mammals. These exercises utilizing underwater detonations do not overlap in space and time with sonar exercises. Explosives from the Multiple Strike Group Exercise have been included in the events described in the next Section. EP23JN08.003 Activities Utilizing Underwater Detonations Underwater detonation activities can occur at various depths depending on the activity (sinking exercise [SINKEX] and mine neutralization), but may also include activities which may have detonations at or just below the surface (SINKEX, gunnery exercise [GUNEX], or missile exercise [MISSILEX]). When the weapons hit the target except for live torpedo shot, 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 (5-inch naval gunfire, 76mm rounds), 2 meters (Maverick, Harpoon, MK-82, MK-83, MK-84), or 50-ft (MK-48 torpedo) as shown in Appendix A of the Navy's application, Table A-7 (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 4. 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 5 at the end of this section. EP23JN08.004 Sinking Exercise (SINKEX) —In a SINKEX, a specially prepared, deactivated vessel is deliberately sunk using multiple weapons systems. The exercise provides training to ship and submarine and aircraft crews in delivering both live and inert ordnance on a real target. These target vessels are remediated to standards set by the Environmental Protection Agency. 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 four to eight hours over one to two days. SINKEXs typically occur only once or twice a year in the HRC. Underwater detonation of several different explosive types could result in the take of marine mammals. Some or all of the following weapons may be employed in a SINKEX: Three HARPOON surface-to-surface and air-to-surface missiles; two to eight air-to-surface Maverick missiles; two to four MK-82 General Purpose Bombs; two Hellfire air-to-surface missiles; one SLAM-ER air-to-surface missile; two-hundred and fifty rounds for a 5-inch gun; and one MK-48 heavyweight submarine-launched torpedo. Surface-to-Surface Gunnery Exercise (S-S GUNEX) —Surface gunnery exercises (GUNEX) take place in the open ocean to provide gunnery practice for Navy and Coast Guard ship crews. GUNEX training events conducted in the Offshore OPAREA involve stationary targets such as a MK-42 FAST or a MK-58 marker (smoke) buoy. The gun systems employed against surface targets include the 5-inch, 76 millimeter (mm), 25-mm chain gun, 20-mm Close-in Weapon System (CIWS), and .50 caliber machine gun. Typical ordnance expenditure for a single GUNEX is a minimum of 21 rounds of 5-inch or 76-mm ammunition, and approximately 150 rounds of 25-mm or .50-caliber 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 S-S GUNEX lasts approximately two to four hours, depending on target services and weather conditions. Detonation of the live 5-inch and 76-mm rounds could result in the take of marine mammals. Naval Surface Fire Support Exercise —Navy surface combatants conduct fire support exercise (FIREX) training events at PMRF on a virtual range against “Fake Island”, located on Barking Sands Tactical Underwater Range (BARSTUR). Fake Island is unique in that it is a virtual landmass simulated in three dimensions. Ships conducting FIREX training against targets on the island are given the coordinates and elevation of targets. PMRF is capable of tracking fired rounds to an accuracy of 30 feet (9.1 m). Detonation of the live 5-inch and 76-mm rounds fired into ocean during this exercise could result in the take of marine mammals. Air-to-Surface Missile Exercise (A-S MISSILEX) —The A-S MISSILEX consists of the attacking platform releasing a forward-fired, guided weapon at the designated towed target. The exercise involves locating the target, then designating the target, usually with a laser. A-S MISSILEX training can take place without the release of a live weapon 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 live-fire exercise in every aspect except that a weapon is not released, nor does it contain any explosives or propellant. The event requires a laser-safe range as the target is designated just as in a live-fire 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. A-S MISSILEX assets include helicopters and/or one to 16 fixed wing aircraft with air-to-surface missiles and anti-radiation missiles (electromagnetic radiation source seeking missiles). When a high-speed anti-radiation missile (HARM) is used, the exercise is called a HARMEX. Targets include SEPTARs, ISTTs, and decommissioned ship hulks. Detonation of live ordnance could result in the take of marine mammals. Surface-to-Surface Missile Exercise (S-S MISSILEX) —Surface-to-surface missile exercise (S-S 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. Engagement is usually with Harpoon missiles or Standard missiles in the surface-to-surface mode. Targets could include virtual targets or the SEPTAR or ship deployed surface target. S-S MISSILEX training is routinely conducted on individual ships with embedded training devices. A S-S MISSILEX could include four to 20 surface-to-surface missiles, SEPTARs, a weapons recovery boat, and a helicopter for environmental and photo evaluation. All missiles are equipped with instrumentation packages or a warhead. Surface-to-air missiles can also be used in a surface-to-surface mode. S-S MISSILEX activities are conducted within PMRF Warning area W-188. Each exercise typically lasts five hours, though future S-S MISSILEXs could range from four to 35 hours. Missile detonation could result in the take of marine mammals. Bombing Exercise (BOMBEX) —Fixed-wing aircraft conduct BOMBEX events against stationary targets (MK-42 FAST or MK-58 smoke buoy) at sea. An aircraft will clear the area, deploy a smoke buoy or other floating target, and then set up a racetrack pattern, dropping on the target with each pass. At PMRF, a range boat might be used to deploy the target for an aircraft to attack. A BOMBEX may involve either live or inert ordnance. Underwater detonation of live ordnance could result in the take of marine mammals. Mine Neutralization —Mine Neutralization events involve 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 subsurface assets. Tactics for neutralization of ground or bottom mines involve a 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 open ocean areas will be detonated at the surface. Inert dummy mines are used in the exercises. The total net explosive weight used against each mine ranges from less than one pound to 20 pounds (0.5 to 9.1 kg). Mine neutralization training takes place offshore in Puuloa Underwater Range, Lima Landing, Naval Inactive Ship Maintenance Facility, MCBH, MCTAB, Barters Point Range, Ewa Training Minefield; and in open-ocean areas. Detonation of live ordnance could result in the take of marine mammals. All demolition activities are conducted in accordance with current Navy directives and approved standard operating procedures. Before any explosive is detonated, divers are transported a safe distance away from the explosive. Standard practices for tethered mines in Hawaiian waters require ground mine explosive charges to be suspended 10 feet (3.0 m) below the surface of the water. EER/IEER AN/SSQ-110A —The Extended Echo Ranging and Improved Extended Echo Ranging (EER/IEER) Systems are air-launched 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/SSQ-110A Sonobuoy, would generate a “ping” (small detonation) and the passive AN/SSQ-101 ADAR Sonobuoy would “listen” 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 expendable and commandable sonobuoy pairs are dropped from a fixed-wing aircraft into the ocean in a predetermined pattern (array) with a few buoys covering a very large area. 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 generating a “ping”. There is only one detonation in the pattern of buoys at a time. Detonation of the buoys could result in the take of marine mammals. Air-to-Surface Gunnery Exercise (A-S GUNEX) —Air-to-Surface GUNEX events are conducted by rotary-wing aircraft against stationary targets (Floating at-sea Target [FAST] and smoke buoy). Rotary-wing aircraft involved in this training activity would include a single SH-60 using either 7.62-mm or .50-caliber door-mounted machine guns. A typical A-S GUNEX will last approximately one hour and involve the expenditure of approximately 400 rounds of 50-caliber or 7.62-mm ammunition. Due to the use of small, inert rounds, A-S GUNEXs are not expected to result in the take of marine mammals. EP23JN08.005 Additional information on the Navy's proposed activities may be found in the LOA Application and the FEIS (Section 2 and Appendices D, E, and J). Description of Marine Mammals in the Area of the Specified Activities There are 27 marine mammal species with possible or confirmed occurrence in the HRC. As indicated in Table 6, there are 25 cetacean species (7 mysticetes and 18 odontocetes) and two pinnipeds. Table 6 also includes the estimated abundance, estimated group size, and estimated probability of detection (based on Barlow 2006) of the species that occur in the HRC. Seven marine mammal species listed as federally endangered under the Endangered Species Act (ESA) occur in the HRC: the humpback whale, North Pacific right whale, sei whale, fin whale, blue whale, sperm whale, and Hawaiian monk seal. The most abundant marine mammals appear to be dwarf sperm whales, striped dolphins, and Fraser's dolphins. The most abundant large whales are sperm whales. BILLING CODE 3510-22-P EP23JN08.006 The Navy has compiled information on the abundance, behavior, status and distribution, and vocalizations of marine mammal species in the Hawaiian waters from peer reviewed literature, the Navy Marine Resource Assessment, NMFS Stock Assessment Reports, and marine mammal surveys using acoustics or visual observations from aircraft or ships. This information may be viewed in the Navy's LOA application and/or the Navy's FEIS for the HRC (see Availability). Additional information is available in NMFS Stock Assessment Reports, which may be viewed at: http://www.nmfs.noaa.gov/pr/sars/species.htm. Based on their rare occurrence in the HRC, the Navy and NMFS do not anticipate any effects to Blue whales, North Pacific right whales, or Northern elephant seals and, therefore, they are not addressed further in this document. Important Reproductive Areas Because the consideration of areas where marine mammals are known to selectively breed or calve are important to both the negligible impact finding necessary for the issuance of an MMPA authorization and the need for NMFS to put forth the means of effecting the least practicable adverse impact paying particular attention to rookeries, mating grounds, and other areas of similar significance, we are emphasizing important reproductive areas within this section. Little is known about the breeding and calving behaviors of many of the marine mammals that occur in the HRC. Some delphinid species have calving peaks once or twice a year, but give birth throughout their ranges. The mysticete species that may occur in the HRC are generally thought to migrate from higher to lower latitudes to breed and calve in the winter. With one notable exception, no breeding or calving areas have been identified in the HRC for the species that occur there. However, the main Hawaiian Islands constitute one of the world's most important habitats for the endangered humpback whale. Nearly two-thirds of the entire North Pacific population of humpback whales migrates to Hawaii each winter to engage in breeding, calving and nursing activities important for the survival of their species. The available sighting information and the known preferred breeding habitat (shallow water) indicates that humpback whale densities are much higher (up to almost four whales/square mile) in certain areas and that humpback mothers and calves are concentrated within the 200-m isobath. The Hawaiian Humpback Whale National Marine Sanctuary worked with Dr. Joe Mobley to compile a figure that generally illustrates humpback whale survey data collected between 1993 and 2003 and indicates areas of high and low density (Mobley 2004, Figure 1). EP23JN08.007 BILLING CODE 3510-22-C A Brief Background on Sound An understanding of the basic properties of underwater sound is necessary to comprehend many of the concepts and analyses presented in this document. A summary is included below. Sound is a wave of pressure variations propagating through a medium (for the sonar considered in this proposed rule, the medium is marine water). Pressure variations are created by compressing and relaxing the medium. Sound measurements can be expressed in two forms: intensity and pressure. Acoustic intensity is the average rate of energy transmitted through a unit area in a specified direction and is expressed in watts per square meter (W/m 2 ). Acoustic intensity is rarely measured directly, it is derived from ratios of pressures; the standard reference pressure for underwater sound is 1 microPascal (μPa); for airborne sound, the standard reference pressure is 20 μPa (Richardson et al. , 1995). Acousticians have adopted a logarithmic scale for sound intensities, which is denoted in decibels (dB). Decibel measurements represent the ratio between a measured pressure value and a reference pressure value (in this case 1 μPa or, for airborne sound, 20 μPa). The logarithmic nature of the scale means that each 10 dB increase is a ten-fold increase in power ( e.g. , 20 dB is a 100-fold increase, 30 dB is a 1,000-fold increase). Humans perceive a 10-dB increase in noise as a doubling of sound level, or a 10 dB decrease in noise as a halving of sound level. The term “sound pressure level” implies a decibel measure and a reference pressure that is used as the denominator of the ratio. Throughout this document, NMFS uses 1 microPascal (denoted re: 1 μPa) as a standard reference pressure unless noted otherwise. It is important to note that decibels underwater and decibels in air are not the same and cannot be directly compared. To estimate a comparison between sound in air and underwater, because of the different densities of air and water and the different decibel standards (i.e., reference pressures) in water and air, a sound with the same intensity (i.e., power) in air and in water would be approximately 63 dB quieter in air. Thus a sound that is 160 dB loud underwater would have the same approximate effective intensity as a sound that is 97 dB loud in air. Sound frequency is measured in cycles per second, or Hertz (abbreviated Hz), and is analogous to musical pitch; high-pitched sounds contain high frequencies and low-pitched sounds contain low frequencies. Natural sounds in the ocean span a huge range of frequencies: from earthquake noise at 5 Hz to harbor porpoise clicks at 150,000 Hz (150 kHz). These sounds are so low or so high in pitch that humans cannot even hear them; acousticians call these infrasonic and ultrasonic sounds, respectively. A single sound may be made up of many different frequencies together. Sounds made up of only a small range of frequencies are called “narrowband”, and sounds with a broad range of frequencies are called “broadband”; airguns are an example of a broadband sound source and tactical sonars are an example of a narrowband sound source. When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different frequencies of sound. Based on available behavioral data, audiograms derived using auditory evoked potential, anatomical modeling, and other data, Southall et al . (2007) designate “functional hearing groups” and estimate the lower and upper frequencies of functional hearing of the groups. Further, the frequency range in which each group's hearing is estimated as being most sensitive is represented in the flat part of the M-weighting functions developed for each group. More specific data is available for certain species (Table 17). The functional groups and the associated frequencies are indicated below: • Low frequency cetaceans (13 species of mysticetes): Functional hearing is estimated to occur between approximately 7 Hz and 22 kHz. • Mid-frequency cetaceans (32 species of dolphins, six species of larger toothed whales, and 19 species of beaked and bottlenose whales): Functional hearing is estimated to occur between approximately 150 Hz and 160 kHz. • High frequency cetaceans (eight species of true porpoises, six species of river dolphins, Kogia , the franciscana, and four species of cephalorhynchids): Functional hearing is estimated to occur between approximately 200 Hz and 180 kHz. • Pinnipeds in Water: Functional hearing is estimated to occur between approximately 75 Hz and 75 kHz, with the greatest sensitivity between approximately 700 Hz and 20 kHz. • Pinnipeds in Air: Functional hearing is estimated to occur between approximately 75 Hz and 30 kHz. Because ears adapted to function underwater are physiologically different from human ears, comparisons using decibel measurements in air would still not be adequate to describe the effects of a sound on a whale. When sound travels away from its source, its loudness decreases as the distance traveled (propagates) by the sound increases. Thus, the loudness of a sound at its source is higher than the loudness of that same sound a kilometer distant. Acousticians often refer to the loudness of a sound at its source (typically measured one meter from the source) as the source level and the loudness of sound elsewhere as the received level. For example, a humpback whale three kilometers from an airgun that has a source level of 230 dB may only be exposed to sound that is 160 dB loud, depending on how the sound propagates. As a result, it is important not to confuse source levels and received levels when discussing the loudness of sound in the ocean. As sound travels from a source, its propagation in water is influenced by various physical characteristics, including water temperature, depth, salinity, and surface and bottom properties that cause refraction, reflection, absorption, and scattering of sound waves. Oceans are not homogeneous and the contribution of each of these individual factors is extremely complex and interrelated. The physical characteristics that determine the sound's speed through the water will change with depth, season, geographic location, and with time of day (as a result, in actual sonar operations, crews will measure oceanic conditions, such as sea water temperature and depth, to calibrate models that determine the path the sonar signal will take as it travels through the ocean and how strong the sound signal will be at a given range along a particular transmission path). As sound travels through the ocean, the intensity associated with the wavefront diminishes, or attenuates. This decrease in intensity is referred to as propagation loss, also commonly called transmission loss. Metrics Used in This Document This section includes a brief explanation of the two sound measurements (sound pressure level (SPL) and sound exposure level (SEL)) frequently used in the discussions of acoustic effects in this document. SPL Sound pressure is the sound force per unit area, and is usually measured in micropascals (μPa), where 1 Pa is the pressure resulting from a force of one newton exerted over an area of one square meter. SPL is expressed as the ratio of a measured sound pressure and a reference level. The commonly used reference pressure level in underwater acoustics is 1 μPa, and the units for SPLs are dB re: 1 μPa. SPL (in dB) = 20 log (pressure/reference pressure) SPL is an instantaneous measurement and can be expressed as the peak, the peak-peak, or the root mean square (rms). Root mean square, which is the square root of the arithmetic average of the squared instantaneous pressure values, is typically used in discussions of the effects of sounds on vertebrates and all references to SPL in this document refer to the root mean square. SPL does not take the duration of a sound into account. SPL is the applicable metric used in the risk continuum, which is used to estimate behavioral harassment takes (see Level B Harassment Risk Function (Behavioral Harassment) Section). SEL SEL is an energy metric that integrates the squared instantaneous sound pressure over a stated time interval. The units for SEL are dB re: 1 μPa 2 s. SEL = SPL + 10log(duration in seconds) As applied to tactical sonar, the SEL includes both the SPL of a sonar ping and the total duration. Longer duration pings and/or pings with higher SPLs will have a higher SEL. If an animal is exposed to multiple pings, the SEL in each individual ping is summed to calculate the total SEL. The total SEL depends on the SPL, duration, and number of pings received. The thresholds that NMFS uses to indicate at what received level the onset of temporary threshold shift (TTS) and permanent threshold shift (PTS) in hearing are likely to occur are expressed in SEL. Potential Effects of Specified Activities on Marine Mammals Exposure to MFAS/HFAS The Navy has requested authorization for the take of marine mammals that may occur incidental to training activities in the HRC utilizing MFAS/HFAS or underwater explosives. The Navy has analyzed other Navy activities in the HRC, both ongoing and proposed, and in consultation with NMFS as a cooperating agency for the HRC EIS, has determined that take of marine mammals incidental to other Navy activities is unlikely and, therefore, has not requested authorization for take of marine mammals that might occur incidental to any other activities. Therefore, NMFS will analyze the potential effects on marine mammals from MFAS/HFAS and underwater detonations, but not from other activities. For the purposes of MMPA authorizations, NMFS's effects assessments have three primary purposes: (1) To put forth the permissible methods of taking within the context of MMPA Level B Harassment (behavioral harassment), Level A Harassment (injury), and mortality (i.e., identify the number and types of take that will occur); (2) to determine whether the specified activity will have a negligible impact on the affected species or stocks of marine mammals (based on the likelihood that the activity will adversely affect the species or stock through effects on annual rates of recruitment or survival); and (3) to determine whether the specified activity will have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (however, there are no subsistence communities that would be affected in the HRC, so this determination is inapplicable for the HRC). More specifically, for activities involving active tactical sonar or underwater detonations, NMFS's analysis will identify the probability of lethal responses, physical trauma, sensory impairment (permanent and temporary threshold shifts and acoustic masking), physiological responses (particular stress responses), behavioral disturbance (that rises to the level of harassment), and social responses that would be classified as behavioral harassment or injury and/or would be likely to adversely affect the species or stock through effects on annual rates of recruitment or survival. In this section, we will focus qualitatively on the different ways that MFAS/HFAS and underwater explosive detonations may affect marine mammals (some of which NMFS would not classify as harassment). Then, in the Estimated Take of Marine Mammals Section, NMFS will relate the potential effects to marine mammals from MFAS/HFAS and underwater detonation of explosives to the MMPA regulatory definitions of Level A and Level B Harassment and attempt to quantify those effects. In its April 14, 2008, Biological Opinion of the U.S. Navy's proposal to conduct four training exercises in the Cherry Point, Virginia Capes, and Jacksonville, Range Complexes NMFS presented a conceptual model of the potential responses of endangered and threatened species upon being exposed to active sonar and the pathways by which those responses might affect the fitness of individual animals that have been exposed, which may then affect the reproduction and/or survival of those individuals. Literature supporting the framework, with examples drawn from many taxa (both aquatic and terrestrial) was included in the “Application of this Approach” and “Response Analyses” sections of that document (available at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm ). This conceptual framework may also be used to describe the responses and pathways for non-endangered and non-threatened species and is included in this document for reference (Figure 2). BILLING CODE 3510-22-P EP23JN08.008 BILLING CODE 3510-22-C Direct Physiological Effects Based on the literature, there are two basic ways that MFAS/HFAS might directly result in physical trauma or damage: Noise-induced loss of hearing sensitivity (more commonly-called “threshold shift”) and acoustically mediated bubble growth. Separately, an animal's behavioral reaction to an acoustic exposure might lead to physiological effects that might ultimately lead to injury or death, which is discussed later in the Stranding section. Threshold Shift (Noise-Induced Loss of Hearing) When animals exhibit reduced hearing sensitivity (i.e., sounds must be louder for an animal to recognize them) following exposure to a sufficiently intense sound, it is referred to as a noise-induced threshold shift (TS). An animal can experience temporary threshold shift (TTS) or permanent threshold shift (PTS). TTS can last from minutes or hours to days (i.e., there is recovery), occurs in specific frequency ranges (i.e., an animal might only have a temporary loss of hearing sensitivity between the frequencies of 1 and 10 kHz)), and can be of varying amounts (for example, an animal's hearing sensitivity might be reduced by only 6 dB or reduced by 30 dB). PTS is permanent (i.e., there is no recovery), but also occurs in a specific frequency range and amount as mentioned. The following physiological mechanisms are thought to play a role in inducing auditory TSs: Effects to sensory hair cells in the inner ear that reduce their sensitivity, modification of the chemical environment within the sensory cells, residual muscular activity in the middle ear, displacement of certain inner ear membranes, increased blood flow, and post-stimulatory reduction in both efferent and sensory neural output (Southall et al. , 2007). The amplitude, duration, frequency, temporal pattern, and energy distribution of sound exposure all affect the amount of associated TS and the frequency range in which it occurs. As amplitude and duration of sound exposure increase, so, generally, does the amount of TS. For continuous sounds, exposures of equal energy (the same SEL) will lead to approximately equal effects. For intermittent sounds, less TS will occur than from a continuous exposure with the same energy (some recovery will occur between exposures) (Kryter et al. , 1966; Ward, 1997). For example, one short but loud (higher SPL) sound exposure may induce the same impairment as one longer but softer sound, which in turn may cause more impairment than a series of several intermittent softer sounds with the same total energy (Ward, 1997). Additionally, though TTS is temporary, very prolonged exposure to sound strong enough to elicit TTS, or shorter-term exposure to sound levels well above the TTS threshold, can cause PTS, at least in terrestrial mammals (Kryter, 1985) (although in the case of MFAS/HFAS, animals are not expected to be exposed to levels high enough or durations long enough to result in PTS). PTS is considered auditory injury (Southall et al. , 2007). Irreparable damage to the inner or outer cochlear hair cells may cause PTS, however, other mechanisms are also involved, such as exceeding the elastic limits of certain tissues and membranes in the middle and inner ears and resultant changes in the chemical composition of the inner ear fluids (Southall et al. , 2007). Although the published body of scientific literature contains numerous theoretical studies and discussion papers on hearing impairments that can occur with exposure to a loud sound, only a few studies provide empirical information on the levels at which noise-induced loss in hearing sensitivity occurs in nonhuman animals. For cetaceans, published data are limited to the captive bottlenose dolphin and beluga (Finneran et al. , 2000, 2002b, 2005a; Schlundt et al. , 2000; Nachtigall et al. , 2003, 2004). For pinnipeds in water, data is limited to Kastak et al. 's measurement of TTS in one harbor seal, one elephant seal, and one California sea lion. Marine mammal hearing plays a critical role in communication with conspecifics, and interpreting environmental cues for purposes such as predator avoidance and prey capture. Depending on the degree (dB), duration, and frequency range of TTS, and the context in which it is experienced, TTS can have effects on marine mammals ranging from discountable to serious (similar to those discussed in auditory masking, below). For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that takes place during a time when the animal is traveling through the open ocean, where ambient noise is lower and there are not as many competing sounds present. Alternatively, a larger amount and longer duration of TTS sustained during time when communication is critical for successful mother/calf interactions could have more serious impacts. Also, depending on the degree and frequency range, the effects of PTS on an animal could range in severity, although it is considered generally more serious because it is a long term condition. Of note, reduced hearing sensitivity as a simple function of development and aging has been observed in marine mammals, as well as humans and other taxa (Southall et al. , 2007), so we can infer that strategies exist for coping with this condition to some degree, though likely not without cost. There is no empirical evidence that exposure to MFAS/HFAS can cause PTS in any marine mammals; instead the probability of PTS has been inferred from studies of TTS (see Richardson et al. 1995). Acoustically Mediated Bubble Growth One theoretical cause of injury to marine mammals is rectified diffusion (Crum and Mao, 1996), the process of increasing the size of a bubble by exposing it to a sound field. This process could be facilitated if the environment in which the ensonified bubbles exist is supersaturated with gas. Repetitive diving by marine mammals can cause the blood and some tissues to accumulate gas to a greater degree than is supported by the surrounding environmental pressure (Ridgway and Howard, 1979). The deeper and longer dives of some marine mammals (for example, beaked whales) are theoretically predicted to induce greater supersaturation (Houser et al. , 2001b). If rectified diffusion were possible in marine mammals exposed to high-level sound, conditions of tissue supersaturation could theoretically speed the rate and increase the size of bubble growth. Subsequent effects due to tissue trauma and emboli would presumably mirror those observed in humans suffering from decompression sickness. It is unlikely that the short duration of sonar pings would be long enough to drive bubble growth to any substantial size, if such a phenomenon occurs. Recent work conducted by Crum et al. (2005) demonstrated the possibility of rectified diffusion for short duration signals, but at sound exposure levels and tissue saturations levels that are improbable to occur in a diving marine mammal. However, an alternative but related hypothesis has also been suggested: Stable bubbles could be destabilized by high-level sound exposures such that bubble growth then occurs through static diffusion of gas out of the tissues. In such a scenario the marine mammal would need to be in a gas-supersaturated state for a long enough period of time for bubbles to become of a problematic size. Yet another hypothesis (decompression sickness) has speculated that rapid ascent to the surface following exposure to a startling sound might produce tissue gas saturation sufficient for the evolution of nitrogen bubbles (Jepson et al. , 2003; Fernandez et al. , 2005). In this scenario, the rate of ascent would need to be sufficiently rapid to compromise behavioral or physiological protections against nitrogen bubble formation. Collectively, these hypotheses can be referred to as “hypotheses of acoustically mediated bubble growth.” Although theoretical predictions suggest the possibility for acoustically mediated bubble growth, there is considerable disagreement among scientists as to its likelihood (Piantadosi and Thalmann, 2004; Evans and Miller, 2003). Crum and Mao (1996) hypothesized that received levels would have to exceed 190 dB in order for there to be the possibility of significant bubble growth due to supersaturation of gases in the blood (i.e., rectified diffusion). More recent work conducted by Crum et al. (2005) demonstrated the possibility of rectified diffusion for short duration signals, but at SELs and tissue saturation levels that are highly improbable to occur in diving marine mammals. To date, Energy Levels (ELs) predicted to cause in vivo bubble formation within diving cetaceans have not been evaluated (NOAA, 2002b). Although it has been argued that traumas from some recent beaked whale strandings are consistent with gas emboli and bubble-induced tissue separations (Jepson et al. , 2003), there is no conclusive evidence of this. However, Jepson et al. (2003, 2005) and Fernandez et al. (2004, 2005) concluded that in vivo bubble formation, which may be exacerbated by deep, long-duration, repetitive dives may explain why beaked whales appear to be particularly vulnerable to sonar exposures. Further investigation is needed to further assess the potential validity of these hypotheses. More information regarding hypotheses that attempt to explain how behavioral responses to MFAS/HFAS can lead to strandings is included in the Behaviorally Mediated Bubble Growth Section, after the summary of strandings. Acoustic Masking Marine mammals use acoustic signals for a variety of purposes, which differ among species, but include communication between individuals, navigation, foraging, reproduction, and learning about their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or auditory interference, generally occurs when sounds in the environment are louder than and of a similar frequency to, auditory signals an animal is trying to receive. Masking is a phenomenon that affects animals that are trying to receive acoustic information about their environment, including sounds from other members of their species, predators, prey, and sounds that allow them to orient in their environment. Masking these acoustic signals can disturb the behavior of individual animals, groups of animals, or entire populations. The extent of the masking interference depends on the spectral, temporal, and spatial relationships between the signals an animal is trying to receive and the masking noise, in addition to other factors. In humans, significant masking of tonal signals occurs as a result of exposure to noise in a narrow band of similar frequencies. As the sound level increases, though, the detection of frequencies above those of the masking stimulus decreases also. This principle is expected to apply to marine mammals as well because of common biomechanical cochlear properties across taxa. Richardson et al. (1995b) argued that the maximum radius of influence of an industrial noise (including broadband low frequency sound transmission) on a marine mammal is the distance from the source to the point at which the noise can barely be heard. This range is determined by either the hearing sensitivity of the animal or the background noise level present. Industrial masking is most likely to affect some species' ability to detect communication calls and natural sounds (i.e., surf noise, prey noise, etc.; Richardson et al. , 1995). The echolocation calls of toothed whales are subject to masking by high frequency sound. Human data indicate low frequency sound can mask high frequency sounds (i.e., upward masking). Studies on captive odontocetes by Au et al. (1974, 1985, 1993) indicate that some species may use various processes to reduce masking effects (e.g., adjustments in echolocation call intensity or frequency as a function of background noise conditions). There is also evidence that the directional hearing abilities of odontocetes are useful in reducing masking at the high frequencies these cetaceans use to echolocate, but not at the low-to-moderate frequencies they use to communication (Zaitseva et al., 1980). As mentioned previously, the functional hearing ranges of mysticetes, odontocetes, and pinnipeds all encompass the frequencies of the sonar sources used in the Navy's training exercises. Additionally, almost all species vocal repertoires span across the frequencies of the sonar sources used by the Navy. The closer the characteristics of the masking signal to the signal of interest, the more likely masking is to occur. However, due to the pulse length and duty cycle of the MFAS/HFAS signal, masking is unlikely to occur as a result of exposure to MFAS/HFAS during the training exercises in the HRC. Impaired Communication In addition to making it more difficult for animals to perceive acoustic cues in their environment, anthropogenic sound presents separate challenges for animals that are vocalizing. When they vocalize, animals are aware of environmental conditions that affect the “active space” of their vocalizations, which is the maximum area within which their vocalizations can be detected before it drops to the level of ambient noise (Brenowitz, 2004; Brumm et al. , 2004; Lohr et al. , 2003). Animals are also aware of environmental conditions that affect whether listeners can discriminate and recognize their vocalizations from other sounds, which are more important than detecting a vocalization (Brenowitz, 1982; Brumm et al. , 2004; Dooling, 2004; Marten and Marler, 1977; Patricelli et al. , 2006). Most animals that vocalize have evolved with an ability to make vocal adjustments to their vocalizations to increase the signal-to-noise ratio, active space, and recognizability of their vocalizations in the face of temporary changes in background noise (Brumm et al. , 2004; Patricelli et al. , 2006). Vocalizing animals will make one or more of the following adjustments to their vocalizations: Adjust the frequency structure; Adjust the amplitude; Adjust temporal structure; or Adjust temporal delivery (see Biological Opinion). Many animals will combine several of these strategies to compensate for high levels of background noise. Anthropogenic sounds that reduce the signal-to-noise ratio of animal vocalizations, increase the masked auditory thresholds of animals listening for such vocalizations, or reduce the active space of an animal's vocalizations impair communication between animals. Most animals that vocalize have evolved strategies to compensate for the effects of short-term or temporary increases in background or ambient noise on their songs or calls. Although the fitness consequences of these vocal adjustments remain unknown, like most other trade-offs animals must make, some of these strategies probably come at a cost (Patricelli et al. , 2006). For example, vocalizing more loudly in noisy environments may have energetic costs that decrease the net benefits of vocal adjustment and alter a bird's energy budget (Brumm, 2004; Wood and Yezerinac, 2006). Shifting songs and calls to higher frequencies may also impose energetic costs (Lambrechts, 1996). Stress Responses Classic stress responses begin when an animal's central nervous system perceives a potential threat to its homeostasis. That perception triggers stress responses regardless of whether a stimulus actually threatens the animal; the mere perception of a threat is sufficient to trigger a stress response (Moberg, 2000; Sapolsky et al. , 2005; Seyle, 1950). Once an animal's central nervous system perceives a threat, it mounts a biological response or defense that consists of a combination of the four general biological defense responses: behavioral responses, autonomic nervous system responses, neuroendocrine responses, or immune response. In the case of many stressors, an animal's first and most economical (in terms of biotic costs) response is behavioral avoidance of the potential stressor or avoidance of continued exposure to a stressor. An animal's second line of defense to stressors involves the autonomic nervous system and the classical “fight or flight” response which includes the cardiovascular system, the gastrointestinal system, the exocrine glands, and the adrenal medulla to produce changes in heart rate, blood pressure, and gastrointestinal activity that humans commonly associate with “stress.” These responses have a relatively short duration and may or may not have significant long-term effect on an animal's welfare. An animal's third line of defense to stressors involves its neuroendocrine or sympathetic nervous systems; the system that has received the most study has been the hypothalmus-pituitary-adrenal system (also known as the HPA axis in mammals or the hypothalamus-pituitary-interrenal axis in fish and some reptiles). Unlike stress responses associated with the autonomic nervous system, virtually all neuro-endocrine functions that are affected by stress—including immune competence, reproduction, metabolism, and behavior—are regulated by pituitary hormones. Stress-induced changes in the secretion of pituitary hormones have been implicated in failed reproduction (Moberg, 1987; Rivier, 1995) and altered metabolism (Elasser et al., 2000), reduced immune competence (Blecha, 2000) and behavioral disturbance. Increases in the circulation of glucocorticosteroids (cortisol, corticosterone, and aldosterone in marine mammals; see Romano et al. , 2004) have been equated with stress for many years. The primary distinction between stress (which is adaptive and does not normally place an animal at risk) and distress is the biotic cost of the response. During a stress response, an animal uses glycogen stores that can be quickly replenished once the stress is alleviated. In such circumstances, the cost of the stress response would not pose a risk to the animal's welfare. However, when an animal does not have sufficient energy reserves to satisfy the energetic costs of a stress response, energy resources must be diverted from other biotic function, which impairs those functions that experience the diversion. For example, when mounting a stress response diverts energy away from growth in young animals, those animals may experience stunted growth. When mounting a stress response diverts energy from a fetus, an animal's reproductive success and its fitness will suffer. In these cases, the animals will have entered a pre-pathological or pathological state which is called “distress” (sensu Seyle 1950) or “allostatic loading” (sensu McEwen and Wingfield, 2003). This pathological state will last until the animal replenishes its biotic reserves sufficient to restore normal function. Relationships between these physiological mechanisms, animal behavior, and the costs of stress responses have also been documented fairly well through controlled experiment; because this physiology exists in every vertebrate that has been studied, it is not surprising that stress responses and their costs have been documented in both laboratory and free-living animals (for examples see, Holberton et al. , 1996; Hood et al. , 1998; Jessop et al. , 2003; Krausman et al. , 2004; Lankford et al. , 2005; Reneerkens et al. , 2002; Thompson and Hamer, 2000). Although no information has been collected on the physiological responses of marine mammals to exposure to anthropogenic sounds, studies of other marine animals and terrestrial animals would lead us to expect some marine mammals to experience physiological stress responses and, perhaps, physiological responses that would be classified as “distress” upon exposure to mid-frequency and low-frequency sounds. For example, Jansen (1998) reported on the relationship between acoustic exposures and physiological responses that are indicative of stress responses in humans (for example, elevated respiration and increased heart rates). Jones (1998) reported on reductions in human performance when faced with acute, repetitive exposures to acoustic disturbance. Trimper et al. (1998) reported on the physiological stress responses of osprey to low-level aircraft noise while Krausman et al. (2004) reported on the auditory and physiology stress responses of endangered Sonoran pronghorn to military overflights. Smith et al. (2004a, 2004b) identified noise-induced physiological transient stress responses in hearing-specialist fish that accompanied short- and long-term hearing losses. Welch and Welch (1970) reported physiological and behavioral stress responses that accompanied damage to the inner ears of fish and several mammals. Hearing is one of the primary senses cetaceans use to gather information about their environment and to communicate with conspecifics. Although empirical information on the relationship between sensory impairment (TTS, PTS, and acoustic masking) on cetaceans remains limited, it seems reasonable to assume that reducing an animal's ability to gather information about its environment and to communicate with other members of its species would be stressful for animals that use hearing as their primary sensory mechanism. Therefore, we assume that acoustic exposures sufficient to trigger onset PTS or TTS would be accompanied by physiological stress responses because terrestrial animals exhibit those responses under similar conditions (NRC, 2003). More importantly, marine mammals might experience stress responses at received levels lower than those necessary to trigger onset TTS. Based on empirical studies of the time required to recover from stress responses (Moberg, 2000), we also assume that stress responses are likely to persist beyond the time interval required for animals to recover from TTS and might result in pathological and pre-pathological states that would be as significant as behavioral responses to TTS. Behavioral Disturbance Behavioral responses to sound are highly variable and context-specific. Exposure of marine mammals to sound sources can result in (but is not limited to) the following observable responses: Increased alertness; orientation or attraction to a sound source; vocal modifications; cessation of feeding; cessation of social interaction; alteration of movement or diving behavior; habitat abandonment (temporary or permanent); and, in severe cases, panic, flight, stampede, or stranding, potentially resulting in death (Southall et al. , 2007). Many different variables can influence an animals perception of and response to (nature and magnitude) an acoustic event. An animals prior experience with a sound type effects whether it is less likely (habituation) or more likely (sensitization) to respond to certain sounds in the future (animals can also be innately pre-disposed to respond to certain sounds in certain ways) (Southall et al. , 2007). Related to the sound itself, the perceived nearness of the sound, bearing of the sound (approaching vs. retreating), similarity of a sound to biologically relevant sounds in the animal's environment (i.e., calls of predators, prey, or conspecifics), and familiarity of the sound may effect the way an animal responds to the sound (Southall et al. , 2007). Individuals (of different age, gender, reproductive status, etc.) among most populations will have variable hearing capabilities, and differing behavioral sensitivities to sounds that will be affected by prior conditioning, experience, and current activities of those individuals. Often, specific acoustic features of the sound and contextual variables (i.e., proximity, duration, or recurrence of the sound or the current behavior that the marine mammal is engaged in or its prior experience), as well as entirely separate factors such as the physical presence of a nearby vessel, may be more relevant to the animal's response than the received level alone. There are few empirical studies of avoidance responses of free-living cetaceans to mid-frequency sonars. Much more information is available on the avoidance responses of free-living cetaceans to other acoustic sources, like seismic airguns and low frequency sonar, than mid-frequency active sonar. Richardson et al. , (1995) noted that avoidance reactions are the most obvious manifestations of disturbance in marine mammals. Behavioral Responses (Southall et al. (2007)) Southall et al. , (2007) reports the results of the efforts of a panel of experts in acoustic research from behavioral, physiological, and physical disciplines that convened and reviewed the available literature on marine mammal hearing and physiological and behavioral responses to man-made sound with the goal of proposing exposure criteria for certain effects. This compilation of literature is very valuable, though Southall et al. note that not all data is equal, some have poor statistical power, insufficient controls, and/or limited information on received levels, background noise, and other potentially important contextual variables—such data were reviewed and sometimes used for qualitative illustration, but were not included in the quantitative analysis for the criteria recommendations. In the Southall et al., (2007) report, for the purposes of analyzing responses of marine mammals to anthropogenic sound and developing critieria, the authors differentiate between single pulse sounds, multiple pulse sounds, and non-pulse sounds. MFAS/HFAS sonar is considered a non-pulse sound. Southall et al., (2007) summarize the reports associated with low and mid-frequency cetacean and pinniped responses to non-pulse sounds (there are no high frequency cetaceans in Hawaii) in Appendix C of their report (incorporated by reference and summarized in the three paragraphs below). The reports that address responses of low frequency cetaceans to non-pulse sounds include data gathered in the field and related to several types of sound sources (of varying similarity to MFAS/HFAS) including: Vessel noise, drilling and machinery playback, low frequency M-sequences (sine wave with multiple phase reversals) playback, low frequency active sonar playback, drill ships, Acoustic Thermometry of Ocean Climate (ATOC) source, and non-pulse playbacks. These reports generally indicate no (or very limited) responses to received levels in the 90 to 120 dB re: 1 Pa range and an increasing likelihood of avoidance and other behavioral effects in the 120 to 160 dB range. As mentioned earlier, though, contextual variables play a very important role in the reported responses and the severity of effects are not linear when compared to received level. Also, though, few of the laboratory or field datasets had common conditions, behavioral contexts or sound sources, so it is not surprising that responses differ. The reports that address responses of mid-frequency cetaceans to non-pulse sounds include data gathered both in the field and the laboratory and related to several different sound sources (of varying similarity to MFAS/HFAS) including: Pingers, drilling playbacks, ship and ice-breaking noise, vessel noise, Acoustic Harassment Devices (AHDs), Acoustic Deterrent Devices (ADDs), MFAS, and non-pulse bands and tones. Southall et al. were unable to come to a clear conclusion regarding these reports. In some cases, animals in the field showed significant responses to received levels between 90 and 120 dB, while in other cases these responses were not seen in the 120 to 150 dB range. The disparity in results was likely due to contextual variation and the differences between the results in the field and laboratory data (animals responded at lower levels in the field). The reports that address the responses of pinnipeds in water to non-pulse sounds include data gathered both in the field and the laboratory and related to several different sound sources (of varying similarity to MFAS/HFAS) including: AHDs, ATOC, various non-pulse sounds used in underwater data communication; underwater drilling, and construction noise. Few studies exist with enough information to include them in the analysis. The limited data suggested that exposures to non-pulse sounds between 90 and 140 dB generally do not result in strong behavioral responses in pinnipeds in water and no data exist at higher received levels. In addition to summarizing the available data, the authors of Southall et al. (2007) developed a severity scaling system with the intent of ultimately being able to assign some level of biological significance to a response. Following is a summary of their scoring system, a comprehensive list of the behaviors associated with each score may be found in the report: • 0-3 (Minor and/or brief behaviors) includes, but is not limited to: No response; minor changes in speed or locomotion (but with no avoidance); individual alert behavior; minor cessation in vocal behavior; minor changes in response to trained behaviors (in laboratory). • 4-6 (Behaviors with higher potential to affect foraging, reproduction, or survival) includes, but is not limited to: Moderate changes in speed, direction, or dive profile; brief shift in group distribution; prolonged cessation or modification of vocal behavior (duration > duration of sound), minor or moderate individual and/or group avoidance of sound; brief cessation of reproductive behavior; or refusal to initiate trained tasks (in laboratory). • 7-9 (Behaviors considered likely to affect the aforementioned vital rates) includes, but is not limited to: Extensive of prolonged aggressive behavior; moderate, prolonged or significant separation of females and dependent offspring with disruption of acoustic reunion mechanisms; long-term avoidance of an area; outright panic, stampede, stranding; threatening or attacking sound source (in laboratory). In Table 7 we have summarized the scores that Southall et al . (2007) assigned to the papers that reported behavioral responses of low-frequency cetaceans, mid-frequency cetaceans, and pinnipeds in water to non-pulse sounds. EP23JN08.009 Potential Effects of Behavioral Disturbance The different ways that marine mammals respond to sound are sometimes indicators of the ultimate effect that exposure to a given stimulus will have on the well-being (survival, reproduction, etc.) of an animal (see Figure 2). There is little marine mammal data quantitatively relating the exposure of marine mammals to sound to effects on reproduction or survival, though data exists for terrestrial species to which we can draw comparisons for marine mammals. Attention is the cognitive process of selectively concentrating on one aspect of an animal's environment while ignoring other things (Posner, 1994). Because animals (including humans) have limited cognitive resources, there is a limit to how much sensory information they can process at any time. The phenomenon called “attentional capture” occurs when a stimulus (usually a stimulus that an animal is not concentrating on or attending to) “captures” an animal's attention. This shift in attention can occur consciously or unconsciously (for example, when an animal hears sounds that it associates with the approach of a predator) and the shift in attention can be sudden (Dukas, 2002; van Rij, 2007). Once a stimulus has captured an animal's attention, the animal can respond by ignoring the stimulus, assuming a “watch and wait” posture, or treat the stimulus as a disturbance and respond accordingly, which includes scanning for the source of the stimulus or “vigilance” (Cowlishaw et al. , 2004). Vigilance is normally an adaptive behavior that helps animals determine the presence or absence of predators, assess their distance from conspecifics, or to attend cues from prey (Bednekoff and Lima,1998; Treves, 2000). Despite those benefits, however, vigilance has a cost of time: when animals focus their attention on specific environmental cues, they are not attending to other activities such a foraging. These costs have been documented best in foraging animals, where vigilance has been shown to substantially reduce feeding rates (Saino, 1994; Beauchamp and Livoreil, 1997; Fritz et al. , 2002). Animals will spend more time being vigilant, which may translate to less time foraging or resting, when disturbance stimuli approach them more directly, remain at closer distances, have a greater group size (for example, multiple surface vessels), or when they co-occur with times that an animal perceives increased risk (for example, when they are giving birth or accompanied by a calf). Most of the published literature, however, suggests that direct approaches will increase the amount of time animals will dedicate to being vigilant. For example, bighorn sheep and Dall's sheep dedicated more time being vigilant, and less time resting or foraging, when aircraft made direct approaches over them (Frid, 2001; Stockwell et al. , 1991). Several authors have established that long-term and intense disturbance stimuli can cause population declines by reducing the body condition of individuals that have been disturbed, followed by reduced reproductive success, reduced survival, or both (Daan et al. , 1996; Madsen, 1994; White, 1983). For example, Madsen (1994) reported that pink-footed geese ( Anser brachyrhynchus ) in undisturbed habitat gained body mass and had about a 46-percent reproductive success compared with geese in disturbed habitat (being consistently scared off the fields on which they were foraging) which did not gain mass and has a 17 percent reproductive success. Similar reductions in reproductive success have been reported for mule deer ( Odocoileus hemionus ) disturbed by all-terrain vehicles (Yarmoloy et al. , 1988), caribou disturbed by seismic exploration blasts (Bradshaw et al. , 1998), caribou disturbed by low-elevation military jet-fights (Luick et al. , 1996), and caribou disturbed by low-elevation jet flights (Harrington and Veitch, 1992). Similarly, a study of elk ( Cervus elaphus ) that were disturbed experimentally by pedestrians concluded that the ratio of young to mothers was inversely related to disturbance rate (Phillips and Alldredge, 2000). The primary mechanism by which increased vigilance and disturbance appear to affect the fitness of individual animals is by disrupting an animal's time budget and, as a result, reducing the time they might spend foraging and resting (which increases an animal's activity rate and energy demand). For example, a study of grizzly bears ( Ursus horribilis ) reported that bears disturbed by hikers reduced their energy intake by an average of 12 kcal/min (50.2 × 103kJ/min), and spent energy fleeing or acting aggressively toward hikers (White et al. 1999). On a related note, many animals perform vital functions, such as feeding, resting, traveling, and socializing, on a diel cycle (24-hr cycle). Substantive behavioral reactions to noise exposure (such as disruption of critical life functions, displacement, or avoidance of important habitat) are more likely to be significant if they last more than one diel cycle or recur on subsequent days (Southall et al. , 2007). Consequently, a behavioral response lasting less than one day and not recurring on subsequent days is not considered particularly severe unless it could directly affect reproduction or survival (Southall et al. , 2007). Stranding and Mortality When a live or dead marine mammal swims or floats onto shore and becomes “beached” or incapable of returning to sea, the event is termed a “stranding” (Geraci et al. , 1999; Perrin and Geraci, 2002; Geraci and Lounsbury, 2005; National Marine Fisheries Service, 2007p). The legal definition for a stranding within the United States is that “a marine mammal is dead and is (i) on a beach or shore of the United States; or (ii) in waters under the jurisdiction of the United States (including any navigable waters); or (B) a marine mammal is alive and is (i) on a beach or shore of the United States and is unable to return to the water; (ii) on a beach or shore of the United States and, although able to return to the water, is in need of apparent medical attention; or (iii) in the waters under the jurisdiction of the United States (including any navigable waters), but is unable to return to its natural habitat under its own power or without assistance.” (16 U.S.C. 1421h). Marine mammals are known to strand for a variety of reasons, such as infectious agents, biotoxicosis, starvation, fishery interaction, ship strike, unusual oceanographic or weather events, sound exposure, or combinations of these stressors sustained concurrently or in series. However, the cause or causes of most stranding are unknown (Geraci et al. , 1976; Eaton, 1979, Odell et al. , 1980; Best, 1982). Numerous studies suggest that the physiology, behavior, habitat relationships, age, or condition of cetaceans may cause them to strand or might pre-dispose them the strand when exposed to another phenomenon. These suggestions are consistent with the conclusions of numerous other studies that have demonstrated that combinations of dissimilar stressors commonly combine to kill an animal or dramatically reduce its fitness, even though one exposure without the other does not produce the same result (Chroussos, 2000; Creel, 2005; DeVries et al. , 2003; Fair and Becker, 2000; Foley et al. , 2001; Moberg, 2000; Relyea, 2005a; 2005b, Romero, 2004; Sih et al. , 2004). Several sources have published lists of mass stranding events of cetaceans during attempts to identify relationships between those stranding events and military sonar (Hildebrand, 2004; IWC, 2005; Taylor et al. , 2004). For example, based on a review of stranding records between 1960 and 1995, the International Whaling Commission (2005) identified ten mass stranding events of Cuvier's beaked whales had been reported and one mass stranding of four Baird's beaked whales ( Berardius bairdii ). The IWC concluded that, out of eight stranding events reported from the mid-1980s to the summer of 2003, seven had been associated with the use of mid-frequency sonar, one of those seven had been associated with the use of low-frequency sonar, and the remaining stranding event had been associated with the use of seismic airguns. Most of the stranding events reviewed by the International Whaling Commission involved beaked whales. A mass stranding of Cuvier's beaked whales in the eastern Mediterranean Sea occurred in 1996 (Frantzis, 1998) and mass stranding events involving Gervais' beaked whales, Blainville's beaked whales, and Cuvier's beaked whales occurred off the coast of the Canary Islands in the late 1980s (Simmonds and Lopez-Jurado, 1991). The stranding events that occurred in the Canary Islands and Kyparissiakos Gulf in the late 1990s and the Bahamas in 2000 have been the most intensively-studied mass stranding events and have been associated with naval maneuvers that were using sonar. Between 1960 and 2006, 48 strandings (68 percent) involved beaked whales, 3 (4 percent) involved dolphins, and 14 (20 percent) involved other whale species. Cuvier's beaked whales were involved in the greatest number of these events (48 or 68 percent), followed by sperm whales (7 or 10 percent), and Blainville's and Gervais' beaked whales (4 each or 6 percent). Naval activities that might have involved active sonar are reported to have coincided with 9 (13 percent) or 10 (14 percent) of those stranding events. Between the mid-1980s and 2003 (the period reported by the International Whaling Commission), we identified reports of 44 mass cetacean stranding events of which at least 7 were coincident with naval exercises that were using mid-frequency sonar. Strandings Associated With MFAS Over the past 12 years, there have been five stranding events coincident with military mid-frequency sonar use that are believed to most likely have been caused by exposure to the sonar: Greece (1996); the Bahamas (2000); Madeira (2000); Canary Islands (2002); and Spain (2006). In 2004, during the RIMPAC exercises, between 150-200 usually pelagic melon-headed whales occupied the shallow waters of the Hanalei Bay, Kaua'i, Hawaii for over 28 hours. NMFS determined that the mid-frequency sonar was a plausible, if not likely, contributing factor in what may have been a confluence of events that led to the Hanalei Bay stranding. A number of other stranding events coincident with the operation of mid-frequency sonar and resulting in the death of beaked whales or other species (Minke whales, dwarf sperm whales, pilot whales) have been reported; however, the majority have not been investigated to the degree necessary to determine the cause of the stranding. Greece (1996) Twelve Cuvier's beaked whales stranded atypically (in both time and space) along a 38.2-kilometer strand of the coast of the Kyparissiakos Gulf on May 12 and 13, 1996 (Frantzis, 1998). From May 11 through May 15, the NATO research vessel Alliance was conducting sonar tests with signals of 600 Hz and 3 kHz and rms SPL of 228 and 226 dB re: 1 μPa, respectively (D'Amico and Verboom, 1998; D'Spain et al. , 2006). The timing and the location of the testing encompassed the time and location of the whale strandings (Frantzis, 1998). Necropsies of eight of the animals were performed, but were limited to basic external examination and sampling of stomach contents, blood, and skin. No ears or organs were collected, and no histological samples were preserved. No apparent abnormalities or wounds were found (Frantzis, 2004). Examination of photos of the animals revealed that the eyes of at least four of the individuals were bleeding. Photos were taken soon after their death (Frantzis, 2004). Stomach contents contained the flesh of cephalopods, indicating that feeding had recently taken place (Frantzis, 1998). All available information regarding the conditions associated with this stranding was compiled, and many potential causes were examined including major pollution events, important tectonic activity, unusual physical or meteorological events, magnetic anomalies, epizootics, and conventional military activities (International Council for the Exploration of the Sea, 2005a). However, none of these potential causes coincided in time with the mass stranding, or could explain its characteristics (International Council for the Exploration of the Sea, 2005a). The robust condition of the animals, plus the recent stomach contents, is not consistent with pathogenic causes (Frantzis, 2004). In addition, environmental causes can be ruled out as there were no unusual environmental circumstances or events before or during this time period (Frantzis, 2004). It was determined that because of the rarity of this mass stranding of Cuvier's beaked whales in the Kyparissiakos Gulf (first one in history), the probability for the two events (the military exercises and the strandings) to coincide in time and location, while being independent of each other, was extremely low (Frantzis, 1998). However, because full necropsies had not been conducted, and no abnormalities were noted, the cause of the strandings could not be precisely determined (Cox et al. , 2006). The analysis of this stranding event provided support for, but no clear evidence for, the cause-and-effect relationship of sonar training activities and beaked whale strandings (Cox et al. , 2006). Bahamas (2000) NMFS and the Navy prepared a joint report addressing the multi-species stranding in the Bahamas in 2000, which took place within 24 hours of U.S. Navy ships using MFAS as they passed through the Northeast and Northwest Providence Channels on March 15-16, 2000. The ships, which operated both AN/SQS-53C and AN/SQS-56, moved through the channel while emitting sonar pings approximately every 24 seconds. Of the 17 cetaceans that stranded over a 36-hr period (Cuvier's beaked whales, Blainville's beaked whales, Minke whales, and a spotted dolphin), 7 animals died on the beach (5 Cuvier's beaked whales, 1 Blainville's beaked whale, and the spotted dolphin) and the other 10 were returned to the water alive (though their fate is unknown). Necropsies were performed on five beaked whales. All five necropsied beaked whales were in good body condition, showing no signs of infection, disease, ship strike, blunt trauma, or fishery related injuries, and three still had food remains in their stomachs. Auditory structural damage was discovered in four of the whales, specifically bloody effusions or hemorrhaging around the ears. Bilateral intracochlear and unilateral temporal region subarachnoid hemorrhage with blood clots in the lateral ventricles were found in two of the whales. Three of the whales had small hemorrhages in their acoustic fats (located along the jaw and in the melon). A comprehensive investigation was conducted and all possible causes of the stranding event were considered, whether they seemed likely at the outset or not. Based on the way in which the strandings coincided with ongoing naval activity involving tactical mid-frequency sonar use, in terms of both time and geography, the nature of the physiological effects experienced by the dead animals, and the absence of any other acoustic sources, the investigation team concluded that mid-frequency sonars aboard U.S. Navy ships that were in use during the sonar exercise in question were the most plausible source of this acoustic or impulse trauma. This sound source was active in a complex environment that included the presence of a surface duct, unusual and steep bathymetry, a constricted channel with limited egress, intensive use of multiple, active sonar units over an extended period of time, and the presence of beaked whales that appear to be sensitive to the frequencies produced by these sonars. The investigation team concluded that the cause of this stranding event was the confluence of the Navy mid-frequency sonar and these contributory factors working together, and further recommended that the Navy avoid operating mid-frequency sonar in situations where these five factors would be likely to occur. This report does not conclude that all five of these factors must be present for a stranding to occur, nor that beaked whales are the only species that could potentially be affected by the confluence of the other factors. Based on this, NMFS believes that the presence of surface ducts, steep bathymetry, and/or constricted channels added to the operation of mid-frequency sonar in the presence of cetaceans (especially beaked whales and, potentially, deep divers) may increase the likelihood of producing a sound field with the potential to cause cetaceans to strand, and therefore, suggests the need for increased vigilance while operating MFAS/HFAS. Madeira, Spain (2000) From May 10-14, 2000, three Cuvier's beaked whales were found atypically stranded on two islands in the Madeira archipelago, Portugal (Cox et al. , 2006). A fourth animal was reported floating in the Madeiran waters by fisherman, but did not come ashore (Woods Hole Oceanographic Institution, 2005). Joint NATO amphibious training peacekeeping exercises involving participants from 17 countries and 80 warships took place in Portugal during May 2-15, 2000. The bodies of the three stranded whales were examined post mortem (Woods Hole Oceanographic Institution, 2005), though only one of the stranded whales was fresh enough (24 hours after stranding) to be necropsied (Cox et al. , 2006). Results from the necropsy revealed evidence of hemorrhage and congestion in the right lung and both kidneys (Cox et al. , 2006). There was also evidence of intercochlear and intracranial hemorrhage similar to that which was observed in the whales that stranded in the Bahamas event (Cox et al. , 2006). There were no signs of blunt trauma, and no major fractures (Woods Hole Oceanographic Institution, 2005). The cranial sinuses and airways were found to be quite clear with little or no fluid deposition, which may indicate good preservation of tissues (Woods Hole Oceanographic Institution, 2005). Several observations on the Madeira stranded beaked whales, such as the pattern of injury to the auditory system, are the same as those observed in the Bahamas strandings. Blood in and around the eyes, kidney lesions, pleural hemorrhages, and congestion in the lungs are particularly consistent with the pathologies from the whales stranded in the Bahamas, and are consistent with stress and pressure related trauma. The similarities in pathology and stranding patterns between these two events suggest that a similar pressure event may have precipitated or contributed to the strandings at both sites (Woods Hole Oceanographic Institution, 2005). Even though no definitive causal link can be made between the stranding event and naval exercises, certain conditions may have existed in the exercise area that, in their aggregate, may have contributed to the marine mammal strandings (Freitas, 2004): Exercises were conducted in areas of at least 547 fathoms (1000 m) depth near a shoreline where there is a rapid change in bathymetry on the order of 547 to 3,281 fathoms (1000-6000 m) occurring across a relatively short horizontal distance (Freitas, 2004); multiple ships were operating around Madeira, though it is not known if MFA sonar was used, and the specifics of the sound sources used are unknown (Cox et al. , 2006, Freitas, 2004); exercises took place in an area surrounded by landmasses separated by less than 35 nm (65 km) and at least 10 nm (19 km) in length, or in an embayment. Exercises involving multiple ships employing MFA near land may produce sound directed towards a channel or embayment that may cut off the lines of egress for marine mammals (Freitas, 2004). Canary Islands, Spain (2002) The southeastern area within the Canary Islands is well known for aggregations of beaked whales due to its ocean depths of greater than 547 fathoms (1000 m) within a few hundred meters of the coastline (Fernandez et al. , 2005). On September 24, 2002, 14 beaked whales were found stranded on Fuerteventura and Lanzarote Islands in the Canary Islands (International Council for Exploration of the Sea, 2005a). Seven whales died, while the remaining seven live whales were returned to deeper waters (Fernandez et al. , 2005). Four beaked whales were found stranded dead over the next 3 days either on the coast or floating offshore. These strandings occurred within near proximity of an international naval exercise that utilized MFAS and involved numerous surface warships and several submarines. Strandings began about 4 hours after the onset of MFA sonar activity (International Council for Exploration of the Sea, 2005a; Fernandez et al. , 2005). Eight Cuvier's beaked whales, one Blainville's beaked whale, and one Gervais' beaked whale were necropsied, six of them within 12 hours of stranding (Fernandez et al., 2005). No pathogenic bacteria were isolated from the carcasses (Jepson et al., 2003). The animals displayed severe vascular congestion and hemorrhage especially around the tissues in the jaw, ears, brain, and kidneys, displaying marked disseminated microvascular hemorrhages associated with widespread fat emboli (Jepson et al., 2003; International Council for Exploration of the Sea, 2005a). Several organs contained intravascular bubbles, although definitive evidence of gas embolism in vivo is difficult to determine after death (Jepson et al., 2003). The livers of the necropsied animals were the most consistently affected organ, which contained macroscopic gas-filled cavities and had variable degrees of fibrotic encapsulation. In some animals, cavitary lesions had extensively replaced the normal tissue (Jepson et al., 2003). Stomachs contained a large amount of fresh and undigested contents, suggesting a rapid onset of disease and death (Fernandez et al., 2005). Head and neck lymph nodes were enlarged and congested, and parasites were found in the kidneys of all animals (Fernandez et al., 2005). The association of NATO MFA sonar use close in space and time to the beaked whale strandings, and the similarity between this stranding event and previous beaked whale mass strandings coincident with sonar use, suggests that a similar scenario and causative mechanism of stranding may be shared between the events. Beaked whales stranded in this event demonstrated brain and auditory system injuries, hemorrhages, and congestion in multiple organs, similar to the pathological findings of the Bahamas and Madeira stranding events. In addition, the necropsy results of the Canary Islands stranding event lead to the hypothesis that the presence of disseminated and widespread gas bubbles and fat emboli were indicative of nitrogen bubble formation, similar to what might be expected in decompression sickness (Jepson et al., 2003; Fernandez et al., 2005). Spain (2006) The Spanish Cetacean Society reported an atypical mass stranding of four beaked whales that occurred January 26, 2006, on the southeast coast of Spain, near Mojacar (Gulf of Vera) in the Western Mediterranean Sea. According to the report, two of the whales were discovered the evening of January 26 and were found to be still alive. Two other whales were discovered during the day on January 27, but had already died. The fourth animal was found dead on the afternoon of May 27, a few kilometers north of the first three animals. From January 25-26, 2006, Standing North Atlantic Treaty Organization (NATO) Response Force Maritime Group Two (five of seven ships including one U.S. ship under NATO Operational Control) had conducted active sonar training against a Spanish submarine within 50 nm (93 km) of the stranding site. Veterinary pathologists necropsied the two male and two female Cuvier's beaked whales. According to the pathologists, the most likely primary cause of this type of beaked whale mass stranding event was anthropogenic acoustic activities, most probably anti-submarine MFAS used during the military naval exercises. However, no positive acoustic link was established as a direct cause of the stranding. Even though no causal link can be made between the stranding event and naval exercises, certain conditions may have existed in the exercise area that, in their aggregate, may have contributed to the marine mammal strandings (Freitas, 2004): Exercises were conducted in areas of at least 547 fathoms (1000 m) depth near a shoreline where there is a rapid change in bathymetry on the order of 547 to 3,281 fathoms (1000-6000 m) occurring across a relatively short horizontal distance (Freitas, 2004); Multiple ships (in this instance, five) were operating MFAS in the same area over extended periods of time (in this case, 20 hours) in close proximity; Exercises took place in an area surrounded by landmasses, or in an embayment. Exercises involving multiple ships employing MFA sonar near land may have produced sound directed towards a channel or embayment that may have cut off the lines of egress for the affected marine mammals (Freitas, 2004). Hanalei Bay (2004) On July 3-4, 2004, approximately 150-200 melon-headed whales occupied the shallow waters of the Hanalei Bay, Kaua'i, Hawaii for over 28 hours. Attendees of a canoe blessing observed the animals entering the Bay in a single wave formation at 7 a.m. on July 3, 2004. The animals were observed moving back into the shore from the mouth of the Bay at 9 a.m. The usually pelagic animals milled in the shallow bay and were returned to deeper water with human assistance beginning at 9:30 a.m. on July 4, 2004, and were out of sight by 10:30 a.m. Only one animal, a calf, was known to have died following this event. The animal was noted alive and alone in the Bay on the afternoon of July 4, 2004 and was found dead in the Bay the morning of July 5, 2004. A full necropsy, magnetic resonance imaging, and computerized tomography examination were performed on the calf to determine the manner and cause of death. The combination of imaging, necropsy and histological analyses found no evidence of infectious, internal traumatic, congenital, or toxic factors. Although cause of death could not be definitively determined, it is likely that maternal separation, poor nutritional condition, and dehydration contributed to the final demise of the animal. Although we do not know when the calf was separated from its mother, the movement into the Bay, the milling and re-grouping may have contributed to the separation or lack of nursing especially if the maternal bond was weak or this was a primiparous calf. Environmental factors, abiotic and biotic, were analyzed for any anomalous occurrences that would have contributed to the animals entering and remaining in Hanalei Bay. The Bay's bathymetry is similar to many other sites within the Hawaiian Island chain and dissimilar to sites that have been associated with mass strandings in other parts of the United States. The weather conditions appeared to be normal for that time of year with no fronts or other significant features noted. There was no evidence of unusual distribution or occurrence of predator or prey species, or unusual harmful algal blooms. Weather patterns and bathymetry that have been associated with mass strandings elsewhere were not found to occur in this instance. A separate event involving melon-headed whales and rough-toothed dolphins took place over the same period of time in the Northern Mariana Islands (Jefferson et al., 2006), which is several thousand miles from Hawaii. Some 500-700 melon-headed whales came into Sasanhaya Bay on 4 July 2004 on the island of Rota and then left of their own accord after 5.5 hours; no known active sonar transmissions occurred in the vicinity of that event. Global reports of these types of events or sightings are of great interest to the scientific community and continuing efforts to enhance reporting in island nations will contribute to our increased understanding of animal behavior and potential causes of stranding events. Exactly what, if any, relationship this event has to the simultaneous events in Hawai'i and whether they might be related to some common factor (e.g., there was a full moon on July 2, 2004) is and will likely remain unknown. However, these two synchronous, nearshore events involving a rarely-sighted species are curious and may point to the range of potential contributing factors for which we lack detailed understanding and which the authors acknowledged might have played some role in the “confluence of events” in Hanalei Bay. The Hanalei event was spatially and temporally correlated with RIMPAC. Official sonar training and tracking exercises in the Pacific Missile Range Facility (PMRF) warning area did not commence until approximately 8 a.m. on July 3 and were thus ruled out as a possible trigger for the initial movement into the Bay. However, six naval surface vessels transiting to the operational area on July 2 intermittently transmitted active sonar (for approximately 9 hours total from 1:15 p.m. to 12:30 a.m.) as they approached from the south. The potential for these transmissions to have triggered the whales' movement into Hanalei Bay was investigated. Analyses with the information available indicated that animals to the south and east of Kaua'i could have detected active sonar transmissions on July 2, and reached Hanalei Bay on or before 7 a.m. on July 3, 2004. However, data limitations regarding the position of the whales prior to their arrival in the Bay, the magnitude of sonar exposure, behavioral responses of melon-headed whales to acoustic stimuli, and other possible relevant factors preclude a conclusive finding regarding the role of sonar in triggering this event. Propagation modeling suggest that transmissions from sonar use during the July 3 exercise in the PMRF warning area may have been detectable at the mouth of the Bay. If the animals responded negatively to these signals, it may have contributed to their continued presence in the Bay. The U.S. Navy ceased all active sonar transmissions during exercises in this range on the afternoon of July 3, 2004. Subsequent to the cessation of sonar use, the animals were herded out of the Bay. While causation of this stranding event may never be unequivocally determined, we consider the active sonar transmissions of July 2-3, 2004, a plausible, if not likely, contributing factor in what may have been a confluence of events. This conclusion is based on: (1) The evidently anomalous nature of the stranding; (2) its close spatiotemporal correlation with wide-scale, sustained use of sonar systems previously associated with stranding of deep-diving marine mammals; (3) the directed movement of two groups of transmitting vessels toward the southeast and southwest coast of Kauai; (4) the results of acoustic propagation modeling and an analysis of possible animal transit times to the Bay; and (5) the absence of any other compelling causative explanation. The initiation and persistence of this event may have resulted from an interaction of biological and physical factors. The biological factors may have included the presence of an apparently uncommon, deep-diving cetacean species (and possibly an offshore, non-resident group), social interactions among the animals before or after they entered the Bay, and/or unknown predator or prey conditions. The physical factors may have included the presence of nearby deep water, multiple vessels transiting in a directed manner while transmitting active sonar over a sustained period, the presence of surface sound ducting conditions, and/or intermittent and random human interactions while the animals were in the Bay. Association Between Mass Stranding Events and Exposure to MFAS Several authors have noted similarities between some of these stranding incidents: they occurred in islands or archipelagoes with deep water nearby, several appeared to have been associated with acoustic waveguides like surface ducting, and the sound fields created by ships transmitting mid-frequency sonar (Cox et al., 2006, D'Spain et al., 2006). Although Cuvier's beaked whales have been the most common species involved in these stranding events (81 percent of the total number of stranded animals and see Figure 3), other beaked whales (including Mesoplodon europeaus, M. densirostris , and Hyperoodon ampullatus ) comprise 14 percent of the total. Other species ( Stenella coeruleoalba, Kogia breviceps and Balaenoptera acutorostrata ) have stranded, but in much lower numbers and less consistently than beaked whales. Based on the evidence available, however, we cannot determine whether (a) Cuvier's beaked whale is more prone to injury from high-intensity sound than other species, (b) their behavioral responses to sound makes them more likely to strand, or (c) they are more likely to be exposed to mid-frequency active sonar than other cetaceans (for reasons that remain unknown). Because the association between active sonar exposures and marine mammals mass stranding events is not consistent—some marine mammals strand without being exposed to sonar and some sonar transmissions are not associated with marine mammal stranding events despite their co-occurrence—other risk factors or a groupings of risk factors probably contribute to these stranding events. Behaviorally Mediated Responses to MFAS/HFAS That May Lead to Stranding Although the confluence of Navy mid-frequency active tactical sonar with the other contributory factors noted in the report was identified as the cause of the 2000 Bahamas stranding event, the specific mechanisms that led to that stranding (or the others) are not understood, and there is uncertainty regarding the ordering of effects that led to the stranding. It is unclear whether beaked whales were directly injured by sound (acoustically mediated bubble growth, addressed above) prior to stranding or whether a behavioral response to sound occurred that ultimately caused the beaked whales be injured and strand. A [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A08-1371. Public record. Not legal advice.