The portions of the VACAPES Study Area addressed in the Navy's application consist of the offshore OPAREA (surface and subsurface waters) and the SUA warning areas (and not the SUA associated with land ranges), and waters extending from the shoreline to the OPAREA boundary (Table 1 of the application). Table 6 of the LOA application provides a list of marine mammal species that have been confirmed and/or have the potential to occur in the VACAPES Study Area.

The VACAPES OPAREA is a set of operating and maneuver areas with defined ocean surface and subsurface operating areas described in detail in Table 1 of the application. The OPAREA is located in the coastal and offshore waters of the western North Atlantic Ocean adjacent to Delaware, Maryland, Virginia, and North Carolina (Figure 1 of the application; 27,661 nm\2\ of surface waters). The northernmost boundary of the OPAREA is located 37 nautical miles (nm) off the entrance to Delaware Bay at latitude 38[deg] 45' N, the farthest point of the eastern boundary is 184 nm east of Chesapeake Bay at longitude 72[deg] 41' W, and the southernmost point is 105 nm southeast of Cape Hatteras, North Carolina, at latitude of 34[deg] 19' N. The western boundary of the OPAREA lies 3 nm from the shoreline at the boundary separating state and Federal waters.

A warning area is airspace of defined dimensions, extending from 3 nm outward from the U.S. coast, which contains activity that may be hazardous to nonparticipating aircraft. The purpose of such warning area is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both.

Description of the Specified Activities

The Navy requests an authorization for take of marine mammals incidental to conducting training operations within the VACAPES Range Complex. These training activities consist of surface warfare, mine warfare, amphibious warfare, strike warfare, and vessel movement. The locations of these activities are described in Figure 1 of the application. A description of each of these training activities within the VACAPES Range Complex is provided below:

Surface Warfare

Surface Warfare (SUW) supports defense of a geographical area (e.g., a zone or barrier) in cooperation with surface, subsurface, and air forces. SUW operations detect, localize, and track surface targets, primarily ships. Detected ships are monitored visually and with radar. Operations include identifying surface contacts, engaging with weapons, disengaging, evasion and avoiding attack, including implementation of radio silence and deceptive measures.

For the proposed VACAPES Range Complex training operations, SUW involving the use of explosive ordnance includes airtosurface Missile Exercises and airtosurface Bombing Exercises that occur at sea. (1) Missile Exercise (AirtoSurface) (MISSILEX (AS)): This exercise would involve fixed winged aircraft crews and helicopter crews who launch missiles at atsea surface targets with the goal of destroying or disabling the target. MISSILEX (AS) training in the VACAPES Range Complex can occur during the day or at night in locations described in Figure 1 of the LOA application. Table 1 below summarizes the levels of MISSILEX planned in the VACAPES Range Complex for the proposed action.
Table 1. Levels of MISSILEX Planned in the VACAPES Range Complex Per Year Operation Platform System/Ordnance Number of Events Missile Exercise (MISSILEX) MH60S, HH60H AGM114 (Hellfire 60 sorties (60 missiles) (Air to Surface) missile)
F/A18, P3C, and P8A AGM65 E/F (Maverick 20 sorties (20 missiles) missile) (2) Bombing Exercise (BOMBEX) (AS): This exercise would involve strike fighter aircraft (F/A18s) delivering explosive bombs against atsea surface targets with the goal of destroying the target. BOMBEX (AS) training in the VACAPES Study Area occurs only during daylight hours in the locations described in Figure 1 of the LOA application. Table 2 below summarizes the levels of BOMBEX planned in the VACAPES Range Complex for the proposed action.
Table 2. Levels of BOMBEX Planned in the VACAPES Range Complex Per Year Operation Platform System/Ordnance Number of Events Bombing Exercise (BOMBEX) F/A18 MK83/GBU32 [1,000 lb High 5 events (20 bombs 4 bombs/ (AirtoSurface, AtSea) Explosive (HE) bomb] event) Mine Warfare/Mine Exercises

Mine Warfare (MIW) includes the strategic, operational, and tactical use of mines and mine countermine measures (MCM). MIW training events are also collectively referred to as Mine Exercises (MINEX). MIW training/MINEX utilizes shapes to simulate mines. These shapes are either concretefilled shapes or metal shapes. No actual explosive mines are used during MIW training in the VACAPES Range Complex study area. MIW training or MINEX is divided into the following.
(1) Mine laying: Crews practice the laying of mine shapes in simulated enemy areas;
(2) Mine countermeasures: Crews practice ``countering'' simulated enemy mines to permit the maneuver of friendly vessels and troops. [[Page 75634]]
``Countering'' refers to both the detection and identification of enemy mines, the marking and maneuver of vessels and troops around identified enemy mines and mine fields, and the disabling of enemy mines. A subset of mine countermeasures is mine neutralization. Mine neutralization refers to the disabling of enemy mines by causing them to selfdetonate either by setting a small explosive charge in the vicinity of the enemy mine, or by using various types of equipment that emit a sound, pressure, or a magnetic field that causes the mine to trip and self detonate. In all cases, actual explosive (live) mines would not be used during training events. Rather, mine shapes are used to simulate real enemy mines. Table 3 below summarizes the levels of mine warfare/mine exercises planned in the VACAPES Range Complex for the proposed action. Table 3. Levels of Mine Warfare/Mine Exercises Planned in the VACAPES Range Complex Per Year Operation Platform System/Ordnance Number of Events Mine Neutralization MH60S AMNS 30 rounds
EOD 20 lb charges 24 events

In the VACAPES Range Complex study areas, MIW training/MINEX events include the use of explosive charges for two and one types of mine countermeasures and neutralization training, respectively. This training would use the Airborne Mine Neutralization System (AMNS) and underwater detonations of mine shapes by Explosive Ordnance Disposal (EOD) divers. MIW training/MINEX would occur only during daylight hours in the locations described in Figure 1 of the LOA application. Amphibious Warfare

Amphibious Warfare (AMW) involves the utilization of naval firepower and logistics in combination with U.S. Marine Corps landing forces to project military power ashore. AMW encompasses a broad spectrum of operations involving maneuver from the sea to objectives ashore, ranging from shore assaults, boat raids, shiptoshore maneuver, shore bombardment and other naval fire support, and air strike and close air support training. AMW that involves the use of explosive ordnance is limited to Firing Exercises (FIREX).

During a FIREX, surface ships use their main battery guns to fire from sea at land targets in support of military forces ashore. On the east coast, the land ranges where FIREX training can take place are limited. Therefore, land masses are simulated during east coast FIREX training using the Integrated Maritime Portable Acoustic Scoring and Simulation System (IMPASS) system, a system of buoys that simulate a land mass. FIREX training using IMPASS would occur only during daylight hours in the locations described in Figure 1 of the LOA application. Table 4 below summarizes the levels of FIREX and IMPASS planned in the VACAPES Range Complex for the proposed action.
Table 4. Levels of FIREX and IMPASS Planned in the VACAPES Range Complex Per Year Operation Platform System/Ordnance Number of Events FIREX with IMPASS CG, DDG 5'' gun (IMPASS) 22 events (858 HE rounds) Strike Warfare

Strike Warfare (STW) operations are the applications of offensive military power at any chosen time and place to help carry out national goals. The systems required to conduct STW include: weapons, launch platforms, and command and control systems, intelligence, surveillance, reconnaissance, and targeting systems, and pilots or crews to operate the systems. STW involving the use of explosive ordnance includes air toair Missile Exercises (MISSILEX (AA)).

Strike fighter and electronic attack aircraft use sensors to detect radar signals from a simulated threat radar site and either simulate or actually launch an explosive or nonexplosive highspeed antiradiation missile (HARM) with the goal of destroying or disabling the threat radar site. HARM missiles are designed to detonate 30 60 ft (9 18 m) above the water surface so as to not destroy the barge target below. Therefore HARM missiles are not included in the underwater explosive exposure modeling since no marine mammal exposures are anticipated. HARM training events are conducted in the daytime and at night in locations described in Figure 1 of the LOA application. Table 5 below summarizes the levels of HARMEX (AA) planned in the VACAPES Range Complex for the proposed action.
Table 5. Levels of HARMEX (AA) Planned in the VACAPES Range Complex Per Year Operation Platform System/Ordnance Number of Events HARM Missile Exercise (HARMEX) F/A18 AGM88 (HARM) 26 sorties (26 missiles) Vessel Movement

Vessel movements are associated with most training operations in the VACAPES Range Complex and include transits to and from the port. Some training operations are strictly vessel movements such as Man Overboard Drills, Tow/Be Towed Exercises, Underway Replenishment, Aircraft Carrier Flight Operations, and use of the transit lanes by submarines when surfaced. Currently, the number of Navy vessels operating in the VACAPES Range Complex study area varies based on training schedules and can range
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from 0 to about 10 vessels at any given time. Ship sizes range from 362 ft (110 m) for a SSN to 1,092 ft (333 m) for a CVN and speeds generally range from 10 to 14 knots during training operations. Operations involving vessel movements occur intermittently and are variable in duration, ranging from a few hours up to 2 weeks. These operations are widely dispersed throughout the operation areas, which is a vast area encompassing 27,661 nm\2\ (an area approximately the size of Indiana) for the VACAPES Range Complex. The Navy logs about 1,400 total vessel days within the Range Complex during a typical year. Consequently, the density of ships within the study area at any given time is extremely low (i.e., less than 0.0004 ships/nm\2\).
Description of Marine Mammals in the Area of the Specified Activities

There are 34 marine mammal species with possible or confirmed occurrence in the VACAPES Range Complex. As indicated in Table 6, there are 33 cetacean species (7 mysticetes and 26 odontocetes) and one pinniped species. Table 6 also includes the federal status of these marine mammal species. Six marine mammal species listed as federally endangered under the Endangered Species Act (ESA) occur in the VACAPES Range Complex: the humpback whale, North Atlantic right whale, sei whale, fin whale, blue whale, and sperm whale. Although it is possible that any of the 34 species of marine mammals may occur in the VACAPES Range Complex, only 24 of those species are expected to occur regularly in the region.
Table 6. Marine Mammal Species Found in the VACAPES Range Complex Family and Scientific Name Common Name Federal Status Order Cetacea
Suborder Mysticeti (baleen whales)
Eubalaena glacialis North Atlantic right whale Endangered Megaptera novaeangliae Humpback whale Endangered Balaenoptera acutorostrata Minke whale .................................. B. brydei Bryde's whale .................................. B. borealis Sei whale Endangered B. physalus Fin whale Endangered B. musculus Blue whale Endangered Suborder Odontoceti (toothed whales)
Physeter macrocephalus Sperm whale Endangered Kogia breviceps Pygmy sperm whale .................................. K. sima Dwarf sperm whale .................................. Ziphius cavirostris Cuvier's beaked whale .................................. Mesoplodon minus True's beaked whale .................................. M. europaeus Gervais' beaked whale .................................. M. bidens Sowerby's beaked whale .................................. M. densirostris Blainville's beaked whale .................................. Steno bredanensis Roughtoothed dolphin .................................. Tursiops truncatus Bottlenose dolphin .................................. Stenella attenuata Pantropical spotted dolphin .................................. S. frontalis Atlantic spotted dolphin .................................. S. longirostris Spinner dolphin .................................. S. clymene Clymene dolphin .................................. S. coeruleoalba Striped dolphin .................................. Delphinus delphis Common dolphin .................................. Lagenodephis hosei Fraser's dolphin .................................. Lagenorhynchus acutus Atlantic whitesided dolphin .................................. [[Page 75636]]
Grampus griseus Risso's dolphin .................................. Peponocephala electra Melonheaded whale .................................. Feresa attenuata Pygmy killer whale .................................. Pseudorca crassidens False killer whale .................................. Orcinus orca Killer whale .................................. Globicephala melas Longfinned pilot whale .................................. G. macrorhynchus Shortfinned pilot whale .................................. Phocoena phocoena Harbor porpoise .................................. Order Carnivora
Suborder Pinnipedia
Phoca vitulina Harbor seal ..................................

The information contained herein relies heavily on the data gathered in the Marine Resource Assessments (MRAs). The Navy MRA Program was implemented by the Commander, Fleet Forces Command, to initiate collection of data and information concerning the protected and commercial marine resources found in the Navy's OPAREAs. Specifically, the goal of the MRA program is to describe and document the marine resources present in each of the Navy's OPAREAs. The MRA for the VACAPES OPAREA was recently updated in 2007 (DoN, 2008).

The MRA data were used to provide a regional context for each species. The MRA represents a compilation and synthesis of available scientific literature (for example, journals, periodicals, theses, dissertations, project reports, and other technical reports published by government agencies, private businesses, or consulting firms), and NMFS reports including stock assessment reports, recovery plans, and survey reports.

The density estimates that were used in previous Navy environmental documents have been recently updated to provide a compilation of the most recent data and information on the occurrence, distribution, and density of marine mammals. The updated density estimates used for the analyses are derived from the Navy OPAREA Density Estimates (NODE) for the Southeast OPAREAS report (DON, 2007).

Density estimates for cetaceans were either modeled using available linetransect survey data or derived using available data in order of preference: (1) through spatial models using linetransect survey data provided by NMFS; (2) using abundance estimates from Mullin and Fulling (2003); (3) or based on the cetacean abundance estimates found in the most current NMFS stock assessment report (SAR) (Waring et al., 2007), which can be viewed at: http://www.nmfs.noaa.gov/pr/sars/species.htm.

For the modelbased approach, density estimates were calculated for each species within areas containing survey effort. A relationship between these density estimates and the associated

environmental parameters such as depth, slope, distance from the shelf break, sea surface temperature, and chlorophyll a concentration was formulated using generalized additive models. This relationship was then used to generate a twodimensional density surface for the region by predicting densities in areas where no survey data exist.

The analyses for cetaceans were based on sighting data collected through shipboard surveys conducted by NMFSNortheast Fisheries Science Center (NEFSC) and Southeast Fisheries Science Center (SEFSC) between 1998 and 2005. Speciesspecific density estimates derived through spatial modeling were compared with abundance estimates found in the most current NMFS SAR to ensure consistency. All spatial models and density estimates were reviewed by and coordinated with NMFS Science Center technical staff and scientists with the University of St. Andrews, Scotland, Centre for Environmental and Ecological Modeling (CREEM). For a more detailed description of the methodology involved in calculating the density estimates provided in this LOA, please refer to the NODE report for the Southeast (DON 2007).

Potential Impacts to Marine Mammal Species

The Navy considers that explosions associated with BOMBEX, MISSILEX, FIREX, and MINEX are the activities with the potential to result in Level A or Level B harassment or mortality of marine mammals. Vessel strikes were also analyzed for their potential effect to marine mammals.

Vessel Strikes

Ship strikes are known to affect large whales and sirenians in the VACAPES Study Area. The most vulnerable marine mammals are those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives (e.g., the sperm whale). In addition, some baleen whales, such as the North Atlantic right whale seem generally unresponsive to vessel sound, making them more susceptible to vessel collisions (Nowacek et al., 2004). These species are primarily large, slow moving whales. Smaller marine mammals, for example, Atlantic bottlenose and Atlantic spotted dolphinsmove quickly throughout the water column and are often seen riding the bow wave of large ships. Marine mammal responses to vessels may include avoidance and changes in dive pattern (NRC, 2003).

After reviewing historical records and computerized stranding databases for evidence of ship strikes involving baleen and sperm whales, Laist et al. (2001) found that accounts of large whale ship strikes involving motorized
[[Page 75637]]
boats in the area date back to at least the late 1800s. Ship collisions remained infrequent until the 1950s, after which point they increased. Laist et al. (2001) report that both the number and speed of motorized vessels have increased over time for transAtlantic passenger services, which transit through the area. They concluded that most strikes occur over or near the continental shelf, that ship strikes likely have a negligible effect on the status of most whale populations, but that for small populations or segments of populations the impact of ship strikes may be significant.

Although ship strikes may result in the mortality of a limited number of whales within a population or stock, Laist et al. (2001) also concluded that, when considered in combination with other humanrelated mortalities in the area (e.g., entanglement in fishing gear), these ship strikes may present a concern for whale populations.

Of 11 species known to be hit by ships, fin whales are struck most frequently; right whales, humpback whales, sperm whales, and gray whales are all hit commonly (Laist et al., 2001). In some areas, one third of all fin whale and right whale strandings appear to involve ship strikes. Sperm whales spend long periods (typically up to 10 minutes; Jacquet et al., 1996) ``rafting'' at the surface between deep dives. This could make them exceptionally vulnerable to ship strikes. Berzin (1972) noted that there were ``many'' reports of sperm whales of different age classes being struck by vessels, including passenger ships and tug boats. There were also instances in which sperm whales approached vessels too closely and were cut by the propellers (NMFS, 2006d).

The east coast is a principal migratory corridor for North Atlantic right whales that travel between the calving/nursery areas in the Southeastern United States and feeding grounds in the northeast U.S. and Canada. Transit to the Study Area from midAtlantic ports requires Navy vessels to cross the migratory route of North Atlantic right whales. Southward right whale migration generally occurs from mid to late November, although some right whales may arrive off the Florida coast in early November and stay into late March (Kraus et al., 1993). The northbound migration generally takes place between January and late March. Data indicate that during the spring and fall migration, right whales typically occur in shallow water immediately adjacent to the coast, with over half the sightings (63 percent) occurring within 18.5 km (10 NM), and 94.1 percent reported within 55 km (30 NM) of the coast (Knowlton et al., 2002). Given the low abundance of North Atlantic right whales relative to other species, the frequency of occurrence of vessel collisions to right whales suggests that the threat of ship strikes is proportionally greater to this species (Jensen and Silber, 2003). Therefore, in 2004, NMFS proposed a right whale vessel collision reduction strategy to consider the establishment of operational measures for the shipping industry to reduce the potential for large vessel collisions with North Atlantic right whales while transiting to and from midAtlantic ports during right whale migratory periods. Although Navy vessel traffic generally represents only 2 3 percent of overall large vessel traffic, based on this biological characteristic and the presence of critical Navy ports along the whales of mid Atlantic migratory corridor, the Navy was the first Federal agency to proactively adopt additional mitigation measures for transits in the vicinity of midAtlantic ports during right whale migration. For purposes of these measures, the midAtlantic is defined broadly to include ports south and east of Block Island Sound southward to South Carolina.

Accordingly, the Navy has proposed mitigation measures to reduce the potential for collisions with surfaced marine mammals (for more details refer to Proposed Mitigation section below). Based on the implementation of Navy mitigation measures, especially during times of anticipated right whale occurrence, and the relatively low density of Navy ships in the Study Area the likelihood that a vessel collision would occur is very low.
Assessment of Marine Mammal Response to Anthropogenic Sound

Marine mammals respond to various types of anthropogenic sounds introduced into the ocean environment. Responses are typically subtle and can include shorter surfacings, shorter dives, fewer blows per surfacing, longer intervals between blows (breaths), ceasing or increasing vocalizations, shortening or lengthening vocalizations, and changing frequency or intensity of vocalizations (NRC, 2005). However, it is not known how these responses relate to significant effects (e.g., longterm effects or population consequences). The following is an assessment of marine mammal responses and disturbances when exposed to anthropogenic sound.

I. Physiology

Potential impacts to the auditory system are assessed by considering the characteristics of the received sound (e.g., amplitude, frequency, duration) and the sensitivity of the exposed animals. Some of these assessments can be numerically based (e.g., temporary threshold shift [TTS] of hearing sensitivity, permanent threshold shift [PTS] of hearing sensitivity, perception). Others will be necessarily qualitative, due to lack of information, or will need to be extrapolated from other species for which information exists.

Potential physiological responses to the sound exposure are ranked in descending order, with the most severe impact (auditory trauma) occurring at the top and the least severe impact occurring at the bottom (the sound is not perceived).

Auditory trauma represents direct mechanical injury to hearing related structures, including tympanic membrane rupture,
disarticulation of the middle ear ossicles, and trauma to the inner ear structures such as the organ of Corti and the associated hair cells. Auditory trauma is always injurious that could result in PTS. Auditory trauma is always assumed to result in a stress response.

Auditory fatigue refers to a loss of hearing sensitivity after sound stimulation. The loss of sensitivity persists after, sometimes long after, the cessation of the sound. The mechanisms responsible for auditory fatigue differ from auditory trauma and would primarily consist of metabolic exhaustion of the hair cells and cochlear tissues. The features of the exposure (e.g., amplitude, frequency, duration, temporal pattern) and the individual animal's susceptibility would determine the severity of fatigue and whether the effects were temporary (TTS) or permanent (PTS). Auditory fatigue (PTS or TTS) is always assumed to result in a stress response.

Sounds with sufficient amplitude and duration to be detected among the background ambient noise are considered to be perceived. This category includes sounds from the threshold of audibility through the normal dynamic range of hearing (i.e., not capable of producing fatigue).

To determine whether an animal perceives the sound, the received level, frequency, and duration of the sound are compared to what is known of the species' hearing sensitivity.

Since audible sounds may interfere with an animal's ability to detect other sounds at the same time, perceived sounds have the potential to result in
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auditory masking. Unlike auditory fatigue, which always results in a stress response because the sensory tissues are being stimulated beyond their normal physiological range, masking may or may not result in a stress response, depending on the degree and duration of the masking effect. Masking may also result in a unique circumstance where an animal's ability to detect other sounds is compromised without the animal's knowledge. This could conceivably result in sensory impairment and subsequent behavior change; in this case, the change in behavior is the lack of a response that would normally be made if sensory impairment did not occur. For this reason, masking also may lead directly to behavior change without first causing a stress response.

The features of perceived sound (e.g., amplitude, duration, temporal pattern) are also used to judge whether the sound exposure is capable of producing a stress response. Factors to consider in this decision include the probability of the animal being naive or experienced with the sound (i.e., what are the known/unknown consequences of the exposure).

The received level is not of sufficient amplitude, frequency, and duration to be perceptible by the animal. By extension, this does not result in a stress response (not perceived).

Potential impacts to tissues other than those related to the auditory system are assessed by considering the characteristics of the sound (e.g., amplitude, frequency, duration) and the known or estimated response characteristics of nonauditory tissues. Some of these assessments can be numerically based (e.g., exposure required for rectified diffusion). Others will be necessarily qualitative, due to lack of information. Each of the potential responses may or may not result in a stress response.

Direct tissue effects Direct tissue responses to sound stimulation may range from tissue shearing (injury) to mechanical vibration with no resulting injury. Any tissue injury would produce a stress response, whereas noninjurious stimulation may or may not.

Indirect tissue effects Based on the amplitude, frequency, and duration of the sound, it must be assessed whether exposure is sufficient to indirectly affect tissues. For example, the hypothesis that rectified diffusion occurs is based on the idea that bubbles that naturally exist in biological tissues can be stimulated to grow by an acoustic field. Under this hypothesis, one of three things could happen: (a) bubbles grow to the extent that tissue hemorrhage occurs (injury); (b) bubbles develop to the extent that a complement immune response is triggered or nervous tissue is subjected to enough localized pressure that pain or dysfunction occurs (a stress response without injury); or (c) the bubbles are cleared by the lung without negative consequence to the animal.

No tissue effects The received sound is insufficient to cause either direct (mechanical) or indirect effects to tissues. No stress response occurs.

II. The Stress Response

The acoustic source is considered a potential stressor if, by its action on the animal, via auditory or nonauditory means, it may produce a stress response in the animal. The term ``stress'' has taken on an ambiguous meaning in the scientific literature, but with respect to the later discussions of allostasis and allostatic loading, the stress response will refer to an increase in energetic expenditure that results from exposure to the stressor and which is predominantly characterized by either the stimulation of the sympathetic nervous system (SNS) or the hypothalamicpituitaryadrenal (HPA) axis (Reeder and Kramer, 2005). The SNS response to a stressor is immediate and acute and is characterized by the release of the catecholamine neurohormones norepinephrine and epinephrine (i.e., adrenaline). These hormones produce elevations in the heart and respiration rate, increase awareness, and increase the availability of glucose and lipids for energy. The HPA response is ultimately defined by increases in the secretion of the glucocorticoid steroid hormones, predominantly cortisol in mammals. The amount of increase in circulating glucocorticoids above baseline may be an indicator of the overall severity of a stress response (Hennessy et al., 1979). Each component of the stress response is variable in time; e.g., adrenalines are released nearly immediately and are used or cleared by the system quickly, whereas cortisol levels may take long periods of time to return to baseline.

The presence and magnitude of a stress response in an animal depends on a number of factors. These include the animal's life history stage (e.g., neonate, juvenile, adult), the environmental conditions, reproductive or developmental state, and experience with the stressor. Not only will these factors be subject to individual variation, but they will also vary within an individual over time. In considering potential stress responses of marine mammals to acoustic stressors, each of these should be considered. For example, is the acoustic stressor in an area where animals engage in breeding activity? Are animals in the region resident and likely to have experience with the stressor (i.e., repeated exposures)? Is the region a foraging ground or are the animals passing through as transients? What is the ratio of young (naive) to old (experienced) animals in the population? It is unlikely that all such questions can be answered from empirical data; however, they should be addressed in any qualitative assessment of a potential stress response as based on the available literature.

The stress response may or may not result in a behavioral change, depending on the characteristics of the exposed animal. However, provided a stress response occurs, we assume that some contribution is made to the animal's allostatic load. Allostasis is the ability of an animal to maintain stability through change by adjusting its physiology in response to both predictable and unpredictable events (McEwen and Wingfield, 2003). The same hormones associated with the stress response vary naturally throughout an animal's life, providing support for particular life history events (e.g., pregnancy) and predictable environmental conditions (e.g., seasonal changes). The allostatic load is the cumulative cost of allostasis incurred by an animal and is generally characterized with respect to an animal's energetic expenditure. Perturbations to an animal that may occur with the presence of a stressor, either biological (e.g., predator) or anthropogenic (e.g., construction), can contribute to the allostatic load (Wingfield, 2003). Additional costs are cumulative and additions to the allostatic load over time may contribute to reductions in the probability of achieving ultimate life history functions (e.g., survival, maturation, reproductive effort and success) by producing pathophysiological states. The contribution to the allostatic load from a stressor requires estimating the magnitude and duration of the stress response, as well as any secondary contributions that might result from a change in behavior.

If the acoustic source does not produce tissue effects, is not perceived by the animal, or does not produce a stress response by any other means, we assume that the exposure does not contribute to the allostatic load. Additionally, without a stress response or auditory masking, it is assumed that there can be no behavioral change. Conversely, any immediate effect of exposure that produces an injury is assumed to also produce a stress response and contribute to the allostatic load.
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III. Behavior

Changes in marine mammal behavior are expected to result from an acute stress response. This expectation is based on the idea that some sort of physiological trigger must exist to change any behavior that is already being performed. The exception to this rule is the case of auditory masking. The presence of a masking sound may not produce a stress response, but may interfere with the animal's ability to detect and discriminate biologically relevant signals. The inability to detect and discriminate biologically relevant signals hinders the potential for normal behavioral responses to auditory cues and is thus considered a behavioral change.

Impulsive sounds from explosions have very short durations as compared to other sounds like sonar or ship noise, which are more likely to produce auditory masking. Additionally the explosive sources analyzed in this document are used infrequently and the training events are typically of short duration. Therefore, the potential for auditory masking is unlikely and no impacts to marine mammals due to auditory masking are anticipated due to implementing the proposed action.

Numerous behavioral changes can occur as a result of stress response. For each potential behavioral change, the magnitude in the change and the severity of the response needs to be estimated. Certain conditions, such as stampeding (i.e., flight response) or a response to a predator, might have a probability of resulting in injury. For example, a flight response, if significant enough, could produce a stranding event. Each altered behavior may also have the potential to disrupt biologically significant events (e.g., breeding or nursing) and may need to be classified as Level B harassment. All behavioral disruptions have the potential to contribute to the allostatic load. This secondary potential is signified by the feedback from the collective behaviors to allostatic loading.
IV. Life Function

IV.1. Proximate Life Functions

Proximate life history functions are the functions that the animal is engaged in at the time of acoustic exposure. The disruption of these functions, and the magnitude of the disruption, is something that must be considered in determining how the ultimate life history functions are affected. Consideration of the magnitude of the effect to each of the proximate life history functions is dependent upon the life stage of the animal. For example, an animal on a breeding ground which is sexually immature will suffer relatively little consequence to disruption of breeding behavior when compared to an actively displaying adult of prime reproductive age.

IV.2. Ultimate Life Functions

The ultimate life functions are those that enable an animal to contribute to the population (or stock, or species, etc.). The impact to ultimate life functions will depend on the nature and magnitude of the perturbation to proximate life history functions. Depending on the severity of the response to the stressor, acute perturbations may have nominal to profound impacts on ultimate life functions. For example, unitlevel use of sonar by a vessel transiting through an area that is utilized for foraging, but not for breeding, may disrupt feeding by exposed animals for a brief period of time. Because of the brevity of the perturbation, the impact to ultimate life functions may be negligible. By contrast, weekly training over a period of years may have a more substantial impact because the stressor is chronic. Assessment of the magnitude of the stress response from the chronic perturbation would require an understanding of how and whether animals acclimate to a specific, repeated stressor and whether chronic elevations in the stress response (e.g., cortisol levels) produce fitness deficits.

The proximate life functions are loosely ordered in decreasing severity of impact. Mortality (survival) has an immediate effect, in that no future reproductive success is feasible and there is no further addition to the population resulting from reproduction. Severe injuries may also lead to reduced survivorship (longevity) and prolonged alterations in behavior. The latter may further affect an animal's overall reproductive success and reproductive effort. Disruptions of breeding have an immediate impact on reproductive effort and may impact reproductive success. The magnitude of the effect will depend on the duration of the disruption and the type of behavior change that was provoked. Disruptions to feeding and migration can affect all of the ultimate life functions; however, the impacts to reproductive effort and success are not likely to be as severe or immediate as those incurred by mortality and breeding disruptions.

Explosive Ordnance Exposure Analysis

The underwater explosion from a weapon would send a shock wave and blast noise through the water, release gaseous byproducts, create an oscillating bubble, and cause a plume of water to shoot up from the water surface. The shock wave and blast noise are of most concern to marine animals. The effects of an underwater explosion on a marine mammal depends on many factors, including the size, type, and depth of both the animal and the explosive charge; the depth of the water column; and the standoff distance between the charge and the animal, as well as the sound propagation properties of the environment. Potential impacts can range from brief effects (such as behavioral disturbance), tactile perception, physical discomfort, slight injury of the internal organs and the auditory system, to death of the animal (Yelverton et al., 1973; O'Keeffe and Young, 1984; DoN, 2001). Nonlethal injury includes slight injury to internal organs and the auditory system; however, delayed lethality can be a result of individual or cumulative sublethal injuries (DoN, 2001). Immediate lethal injury would be a result of massive combined trauma to internal organs as a direct result of proximity to the point of detonation (DoN, 2001). Generally, exposures to higher levels of impulse and pressure levels would result in worse impacts to an individual animal.

Injuries resulting from a shock wave take place at boundaries between tissues of different density. Different velocities are imparted to tissues of different densities, and this can lead to their physical disruption. Blast effects are greatest at the gasliquid interface (Landsberg, 2000). Gascontaining organs, particularly the lungs and gastrointestinal tract, are especially susceptible (Goertner, 1982; Hill, 1978; Yelverton et al., 1973). In addition, gascontaining organs including the nasal sacs, larynx, pharynx, trachea, and lungs may be damaged by compression/expansion caused by the oscillations of the blast gas bubble (Reidenberg and Laitman, 2003). Intestinal walls can bruise or rupture, with subsequent hemorrhage and escape of gut contents into the body cavity. Less severe gastrointestinal tract injuries include contusions, petechiae (small red or purple spots caused by bleeding in the skin), and slight hemorrhaging (Yelverton et al., 1973).

Because the ears are the most sensitive to pressure, they are the organs most sensitive to injury (Ketten, 2000). Soundrelated damage associated with blast noise can be theoretically distinct from injury from the shock wave, particularly farther from the explosion. If an animal is able to hear a noise, at some level it can damage its hearing by
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causing decreased sensitivity (Ketten, 1995) (See Assessment of Marine Mammal Response to Anthropogenic Sound Section above). Soundrelated trauma can be lethal or sublethal. Lethal impacts are those that result in immediate death or serious debilitation in or near an intense source and are not, technically, pure acoustic trauma (Ketten, 1995). Sublethal impacts include hearing loss, which is caused by exposures to perceptible sounds. Severe damage (from the shock wave) to the ears includes tympanic membrane rupture, fracture of the ossicles, damage to the cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle ear. Moderate injury implies partial hearing loss due to tympanic membrane rupture and blood in the middle ear. Permanent hearing loss also can occur when the hair cells are damaged by one very loud event, as well as by prolonged exposure to a loud noise or chronic exposure to noise. The level of impact from blasts depends on both an animal's location and, at outer zones, on its sensitivity to the residual noise (Ketten, 1995).

The exercises that use explosives include: FIREX with IMPASS, MISSILEX, BOMBEX, and MINEX. Table 7 summarizes the number of events (per year by season) and specific areas where each occurs for each type of explosive ordnance used. For most of the operations, there is no difference in how many events take place between the different seasons. Fractional values are a result of evenly distributing the annual totals over the four seasons. For example, there are 45 Hellfire events per year that can take place in Air Kilo during any season, so there are 11.25 events modeled for each season. However, the 20 lb charge MINEX events are more likely to take place in the summer and this is represented in the seasonal allocation of events.
Table 7. Number of Explosive Events within the VACAPES Range Complex SubArea Ordnance Winter Spring Summer Fall Annual Totals MISSILEX ................... ................... .................. .................. 106 AirK Hellfire 11.25 11.25 11.25 11.25 .................. W72A (2) Hellfire 3.75 3.75 3.75 3.75 .................. AirE, F, I, J Harm 6.50 6.50 6.50 6.50 .................. AirK Maverick 5 5 5 5 .................. FIREX ................... ................... .................. .................. 22 5C/D 5'' rounds 1.83 1.83 1.83 1.83 .................. 7C/D and 8C/D 5'' rounds 1.83 1.83 1.83 1.83 .................. 1C1/2 5'' rounds 1.83 1.83 1.83 1.83 .................. MINEX ................... ................... .................. .................. 54 W50 UNDET 5 LB* 7.50 7.50 7.50 7.50 .................. W50 UNDET 20 LB 4.00 4.00 12.00 4.00 .................. BOMBEX ................... ................... .................. .................. 5 AirK MK83** 1.25 1.25 1.25 1.25 .................. * The use of 3.24 lb charges during AMNS training were conservatively modeled as 5 lb charges. ** One event using the MK 83 bombs consists of 4 bombs being dropped in succession. For example, in VACAPES Air K there are 5 MK 83 events, which mean that a total of 20 bombs will be dropped per year.

Acoustic Environment

Sound propagation (the spreading or attenuation of sound) in the oceans of the world is affected by several environmental factors: water depth, variations in sound speed within the water column, surface roughness, and the geoacoustic properties of the ocean bottom. These parameters can vary widely with location.

Four types of data are used to define the acoustic environment for each analysis site:

Seasonal Sound Velocity Profiles (SVP) Plots of propagation speed (velocity) as a function of depth, or SVPs, are a fundamental tool used for predicting how sound will travel. Seasonal SVP averages were obtained for each training area.

Seabed Geoacoustics The type of sea floor influences how much sound is absorbed and how much sound is reflected back into the water column.

Wind Speeds \ Several environmental inputs, such as wind speed and surface roughness, are necessary to model acoustic propagation in the prospective training areas.

Bathymetry data Bathymetry data are necessary to model acoustic propagation and were obtained for each of the training areas. Acoustic Effects Analysis

The acoustic effects analysis presented in the following sections is briefly described for each major type of exercise. A more indepth effects analysis is in Appendix A of the LOA application.

1. FIREX (with IMPASS)

Modeling was completed for a 5in. round, 8lb NEW charge exploding at a depth of 1 ft (0.3 m). The analytical approach begins using a highfidelity acoustic model to estimate energy in each 5in. explosive round. Impact areas are calculated by summing the energy from multiple explosions over a firing exercise (FIREX) mission, and determining the impact area based on the thresholds and criteria. Level B exposures were determined based on
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the 177 dB re 1 microPa\2\sec (energy) criteria for behavioral disturbance (without TTS) due to the use of multiple explosions.

Impact areas for a full FIREX (with IMPASS) event must account for the time and space distribution of 39 explosions, as well as the movement of animals over the several hours of the exercise. The total impact area for the 39shot event is calculated as the sum of small effect areas for seven FIREX missions (each with four to six rounds fired) and one preFIREX action (with six rounds fired). Table 8 shows the Zone of Influence (ZOI) results of the model estimation. Table 8. Estimated ZOIs (km2) for a single FIREX (with IMPASS) Event (39 rounds) Level B ZOI @ 177 dB re 1 Area* microPa\2\sec (multiple Level B ZOI @ Level A ZOI @ 205 dB re 1 detonations only) 23 psims microPa\2\sec or 13 psims 5C/D NA\**\ 3.7044 0.16464 \*\Please see Figure 1 on page 22 of the LOA application for the locations of these areas. \**\In these areas, which occur in deeper water, the 23 psims criteria dominates over the 177 dB re 1 microPa\2\sec behavioral disturbance criteria and therefore was used in the analysis.

The ZOI, when multiplied by the animal densities and the total number of events (Table 7), provides the exposure estimates for that animal species for the nominal exercise case of 39 5in. explosive rounds. The potential effects would occur within a series of small impact areas associated with the precalibration rounds and missions spread out over a period of several hours. Additionally, target locations are changed from event to event and because of the time lag between events, it is highly unlikely, even if a marine mammal were present (not accounting for mitigation), that the marine mammal would be within the small exposure zone for more than one event.

FIREX (with IMPASS) is restricted to three locations in the VACAPES Range Complex. In addition to other mitigation measures, dedicated lookouts monitor the target area for marine mammals before the exercise, during the deployment of the IMPASS array, and during the return to firing position. Prior to the exercise, the area would be visually monitored when the IMPASS sonobuoy array is being deployed by the ship at the detonation location, as well as while returning to the firing position. During the actual firing of the weapon, the participants involved must be able to observe the intended ordnance impact area to ensure the area is free of range transients, however, this observation would be conducted from the firing position or other safe distance. Due to distance between the firing position and the safety zone, lookouts are only expected to visually detect breaching whales, whale blows, and large pods of dolphins and porpoises. Firing would not commence unless the intended ordnance impact area is visible. Implementation of mitigation measures like these reduce the likelihood of exposure and potential effects in the ZOI and eliminate the likelihood of mortality.

2. BOMBEX

Modeling was completed for one explosive source involved in BOMBEX, each assumed detonation at 1m depth. The NEW used in simulations of the MK83 is 415.8lb. Determining the ZOI for the thresholds in terms of total energy flux density (EFD), impulse, peak pressure and 1/3 octave bands EFD must treat the sequential explosions differently than the single detonations. For the MK83, two factors are involved for the sequential explosives that deal with the spatial and temporal distribution of the detonations as well as the effective accumulation of the resultant acoustics. In view of the ZOI determinations, the sequential detonations are modeled as a single point event with only the EFD summed incoherently. The multiple explosion energy criterion was used to determine the ZOI for the Level B without TTS exposure analysis.

Table 9 shows the ZOI results of the model estimation. The ZOI, when multiplied by the animal densities and total number of events (Table 7), provides the exposure estimates for that animal species for the given bomb source.

BOMBEX is restricted to one location in the VACAPES Range Complex. In addition to other mitigation measures, aircraft will survey the target area for marine mammals before and during the exercise. Ships will not fire on the target until the area is surveyed and determined to be free of marine mammals. The exercise will be suspended if any marine mammals enter the buffer area. Implementation of mitigation measures like these effectively reduce exposures in the ZOI and eliminate the likelihood of mortality.
Table 9. Estimated ZOIs (km\2\) for BOMBEX Level B ZOI @ 177 dB re 1 microPa\2\sec Level B ZOI @ 182 dB re 1 Level A ZOI @ 205 dB re 1 Mortality ZOI @ 30.5 psi (multiple detonations only) microPa\2\sec or 23 psi microPa\2\sec or 13 psi Area Ordnance
Win Spr Sum Fall Win Spr Sum Fall Win Spr Sum Fall Win Spr Sum Fall AirK MK83* 135.04 555.51 713.99 912.05 NA NA NA NA 4.28 4.01 6.39 4.55 0.05 0.05 0.05 0.05 [[Page 75642]]

3. MINEX

The Comprehensive Acoustic System Simulation/Gaussian Ray Bundle (CASS/GRAB) (OAML, 2002) model, modified to account for impulse response, shockwave waveform, and nonlinear shockwave effects, was run for acousticenvironmental conditions derived from the
Oceanographic and Atmospheric Master Library (OAML) standard databases. The explosive source was modeled with standard similitude formulas, as in the Churchill FEIS. Because all the sites are shallow (less than 50 m), propagation model runs were made for bathymetry in the range from 10 m to 40 m.

Estimated ZOIs varied as much within a single area as from one area to another, which had been the case for the Virtual At Sea Training (VAST)/IMPASS (DoN, 2003). There was, however, little seasonal dependence. As a result, the ZOIs are stated as mean values with a percentage variation. Generally, in the case of ranges determined from energy metrics, as the depth of water increases, the range shortens. The single explosion TTSenergy criterion (182 dB re 1
microPa\2\

The total ZOI, when multiplied by the animal densities and total number of events (Table 7), provides the exposure estimates for that animal species for each specified charge. Because of the time lag between detonations, it is highly unlikely, even if a marine mammal were present (not accounting for mitigation), that the marine mammal would be within the small exposure zone for more than one detonation. Underwater detonations are restricted to one area in the VACAPES Range Complex. In addition to other mitigation measures, observers will survey the target area for marine mammals for 30 minutes pre and 30 minutes postdetonation. Detonations will be suspended if a marine mammal enters the Zone of Influence and will only restart after the area has been clear for a full 30 minutes. Implementation of mitigation measures like these reduce the likelihood of exposure and potential effects in the ZOI and eliminate the likelihood of mortality. Table 10. Estimated ZOIs (km\2\) for MINEX
ZOIs
Threshold
5lb shot 20lb shot Level A ZOI @ 13 psi 0.03 km\2\ 10% minus> 10% Level B ZOI @ 182 dB re 1 0.2 km\2\ sec minus> 25% minus> 25% 4. MISSILEX (Hellfire, Harm, and Maverick)

The HARM missile explodes no less than 30 feet (9.1 m) above the surface of the water, s

FOR FURTHER INFORMATION CONTACT

Shane Guan, Office of Protected Resources, NMFS, (301) 7132289, ext. 137.