Taking and Importing Marine Mammals: U.S. Navy Training in the Cherry Point Range Complex
Federal Register: March 16, 2009 (Volume 74, Number 49)
Proposed Rules
Page 11052-11077
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DOCID:fr16mr09-23
Page 11052
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration 50 CFR Part 218
RIN 0648-AX10
Taking and Importing Marine Mammals; U.S. Navy Training in the
Cherry Point 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 Cherry Point Range Complex for the period of May 2009 through May 2014. 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 April 6, 2009.
ADDRESSES: You may submit comments, identified by 0648-AX10, 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 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 (enter NA in the required fields if you wish to remain anonymous). Attachments to electronic comments will be accepted in Microsoft Word, Excel, WordPerfect, or
Adobe PDF file formats only.
FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected
Resources, NMFS, (301) 713-2289, ext. 137.
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
Draft Environmental Impact Statement (DEIS) for the Cherry Point Range
Complex was published on September 12, 2008, and may be viewed at http://www.NavyCherryPointRangeComplexEIS.com. NMFS participated in the development of the Navy's DEIS as a cooperating agency under the
National Environmental Policy Act (NEPA).
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 13, 2008, NMFS received an application from the Navy requesting authorization for the take of Atlantic spotted dolphin incidental to the proposed training activities in the Cherry Point
Range Complex over the course of 5 years. These training activities are classified as military readiness activities. The Navy states that these training activities may cause various impacts to marine mammal species in the proposed Cherry Point Range Complex area. The Navy requests an authorization to take two individuals of this species annually by Level
B Harassment. Please refer to the take table on page 6 of the Addendum of the LOA application for detailed information of the potential exposures from explosive ordnance (per year) for marine mammals in the
Cherry Point Range Complex. However, due to the implementation of the proposed mitigation and monitoring measures, NMFS believes that the actual take would be less than estimated.
Description of the Specified Activities
The Navy Cherry Point Range Complex geographically encompasses offshore and near-shore operating areas (OPAREAs), instrumented ranges, and special use airspace (SUA) located along the southern east coast
(North Carolina and South Carolina) of the U.S. Atlantic coast (see
Figure 1 of the LOA application). The action area includes the area from the shoreline to the 3 nm (5.6 km) boundary of the OPAREA, as well as the Cherry Point OPAREA. Together, components of the Navy Cherry
Point Range Complex encompass: 18,966 nm\2\ of special use airspace (warning area); 18,617 nm\2\ of offshore surface and subsurface OPAREA; and 12,529 nm\2\ of subsurface area greater than 100 fathoms
(600 ft) in depth.
In the application submitted to NMFS, the Navy requests an authorization to take marine mammals incidental to conducting training operations within the Cherry Point Range Complex. These training activities consist of surface warfare, mine warfare, amphibious warfare, and vessel movement. A description of each
Page 11053
of these training activities 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 Cherry Point
Range Complex training operations, SUW events involving the use of explosive ordnance include air-to-surface Missile Exercises (MISSILEX) that occur at sea.
Air-to-surface missile exercises involve helicopter (AH-1W) crews launching missiles at at-sea surface targets with the goal of destroying or disabling the target. MISSILEX (A-S) training in the Navy
Cherry Point Study Area can occur during the day or at night. Table 1 below summarizes the level of MISSILEX planned in the Cherry Point
Range Complex for the proposed action.
Table 1--Level of MISSILEX Planned in the Cherry Point Range Complex per Year
Potential time of
Operation
Platform
System/ordnance
Number of events
day
Missile Exercise (MISSILEX)
AH-1W........... AGM-114 (Hellfire; 8- 8 sorties (5 HE
Day or Night.
(Air to Surface).
pound [lb] Net
missiles; 3
Explosive Weight [NEW] NEPM).
High Explosive [HE] rounds \1\ and Non-
Explosive Practice
Munitions [NEPM]).
Tube-launched,
8 sorties (8
Optically tracked,
missiles).
Wire-guided (TOW)
Missile (all 15.33 NEW
HE rounds)\1\.
\1\ Uses stationary or towed surface targets; 1 missile/sortie.
Mine Warfare/Mine Exercises
Mine Warfare (MIW) includes the strategic, operational, and tactical use of mines and mine countermine measures (MCM). MIW is divided into two basic subdivisions: (
-
The laying of mines to degrade the enemy's capabilities to wage land, air, and maritime warfare, and
(b) the countering of enemy-laid mines to permit friendly maneuver or use of selected land or sea areas (DoN, 2007d).
MIW consists of two unit level operations: Airborne mine countermeasures (AMCM) and mine neutralization. AMCM or Mine
Countermeasures Exercises (MCMEX) train forces to detect, identify, classify, mark, avoid, and disable (or verify destruction of) underwater mines (bottom or moored) using a variety of methods including air, surface, sub-surface, and ground assets. The AMCM systems include mine hunting sonar (AQS-24A), influence mine sweeping systems (MK-105 and MK-104), anti-mine ordnance (Airborne Mine
Neutralization System [AMNS]), and moored mine sweep system (MK-103).
Mine Neutralization operations involve the detection, identification, evaluation, rendering safe, and disposal of underwater
Unexploded Ordnance (UXO) that constitutes a threat to ships or personnel. Mine hunting techniques involve divers, specialized sonar, and unmanned underwater vehicles (UUVs) to locate and classify the mines and then destroy them using one of two methods: mechanical
(explosive cutters) or influence (matching the acoustic, magnetic, or pressure signature of the mine).
In addition to the current mine exercises (AMCM), the Organic
Airborne Mine Countermeasures (OAMCM) training exercises will begin in the Navy Cherry Point Operating Area (OPAREA) as these new systems are introduced into the fleet. The OAMCM systems include mine hunting sonar
(AQS-20), influence mine sweeping towed arrays (Organic Airborne and
Surface Influence Sweep [OASIS]) that emulates the magnetic and acoustic signatures of transit platforms, anti-mine ordnance systems
(Rapid Airborne Mine Clearance System [RAMICS] and AMNS), and mine hunting laser (Airborne Laser Mine Detection System [ALMDS]) that uses a light imaging detecting and ranging (LIDAR) to detect, localize, and classify near-surface moored/floating mines.
MIW training using Explosive Ordnance Disposal (EOD) underwater detonations in the Navy Cherry Point Study Area occur only during daylight hours in the locations described in Figure 1 of the LOA application. Table 2 below shows a summarized level of MIW in the
Cherry Point Study Area.
Table 2--Level of Mine Warfare Planned in the Cherry Point Range Complex per Year
Number of
Potential time
Duration of
Operation
Platform
System/ordnance events per year
of day
event
Mine Neutralization.......... EOD.......... 20 lb NEW
20 events...... Day............ 8 hours. charges.
EOD personnel detect, identify, evaluate, and neutralize mines. The
EOD mission during training is to locate and neutralize mine shapes after they are initially located by another source, such as an MCM or coastal minehunter MHC class ship or an MH-53 or MH-60 helicopter. For underwater detonations, EOD divers are deployed from a ship or small boat to practice neutralizing a mine shape underwater. The neutralization exercise in the water is normally done with an explosive charge of 20-lbs NEW. The initiation of the charge is controlled remotely by EOD personnel. If the mine shape were an actual mine, it would explode due to the pressure and energy exerted in the water from the smaller EOD explosive charge. This training is conducted only during day light hours in the Cherry Point Area.
Amphibious Warfare
Amphibious Warfare (AMW) involves the utilization of naval firepower and logistics in combination with U.S. Marine Corps (USMC) 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, ship-to- shore maneuver, shore bombardment and other naval fire support, and air strike
Page 11054
and close air support training. In the Cherry Point Study Area, AMW training 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 in the Cherry Point Study Area would occur only during daylight hours in the locations described in
Figure 1 of the LOA application. Table 3 below summarizes the levels of
FIREX with IMPASS planned in the Cherry Point Range Complex for the proposed action.
Table 3--Level of FIREX With IMPASS Planned in the Cherry Point Range Complex per Year
Number of
Potential time
Duration of
Operation
Platform
System/ordnance
events
of day
event
FIREX with IMPASS............ CG, DDG...... 5'' gun
2 events (78
Day............ 12 hours.
(IMPASS).
rounds).
Vessel Movement
Vessel movements are associated with most activities under the training operations in the Navy Cherry Point Study Area. Currently, the number of Navy vessels operating in the Navy Cherry Point Study Area varies based on training schedules and can range from 0 to about 10 vessels at any given time. Ship sizes range from 362 ft for a submarine
(SSN) to 1,092 ft for an aircraft carrier (CVN) and speeds generally range from 10 to 14 knots (kt). 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 OPAREA, which is a vast area encompassing 18,617 square nautical miles (nm\2\) (an area approximately the size of West Virginia). The
Navy logs about 950 total vessel days within the Study Area during a typical year. Consequently, the density of ships within the Study Area at any given time is extremely low (i.e., less than 0.005 ships/nm\2\).
Description of Marine Mammals in the Area of the Specified Activities
There are 33 cetacean species, 4 pinniped species, and 1 sirenian species that have the potential or are confirmed to occur in the Cherry
Point Range Complex (DoN, 2008). However, only 34 of those species are expected to occur regularly in the OPAREA, as indicated in Table 4. The remaining species are considered extralimital in the Study Area; indicating there are one or more records of an animal's presence in the
Study Area, but it is considered beyond the normal range of the species. Extralimital species will not be analyzed further in this study.
Table 4--Marine Mammal Species Found in the Cherry Point Range Complex
Family and scientific name
Common name
Federal status
Order Cetacea
Suborder Mysticeti (baleen whales)
Eubalaena glacialis......... North Atlantic right Endangered. whale.
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........... Rough-toothed 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....
Grampus griseus............. Risso's dolphin.....
Peponocephala electra....... Melon-headed whale..
Feresa attenuata............ Pygmy killer whale..
Pseudorca crassidens........ False killer whale..
Orcinus orca................ Killer whale........
Page 11055
Globicephala melas.......... Long-finned pilot whale.
G. macrorhynchus............ Short-finned pilot whale.
Phocoena phocoena........... Harbor porpoise.....
Order Carnivora
Suborder Pinnipedia (seals, sea lions, walruses)
Phoca vitulina.............. Harbor seal.........
Order Sirenia
Trichechus manatus.......... West Indian manatee. Endangered.
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 Cherry Point Study Area was recently updated in 2008 (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 (e.g., 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 presented in this assessment are derived from the Navy OPAREA Density Estimates
(NODE) for the Southeast OPAREAs report (DoN, 2007). Quantification of marine mammal density and abundance was primarily accomplished by evaluating line-transect survey data which was collected by the NMFS
Northeast and Southeast Fisheries Science Centers (NEFSC and SEFSC).
The NEFSC and SEFSC are the technical centers within NMFS that are responsible for collecting and analyzing data to assess marine mammal stocks in the U.S. Atlantic Exclusive Economic Zone (EEZ). These data sets were analyzed and evaluated in conjunction with regional subject matter experts, NMFS technical staff, and scientists with the
University of St. Andrews, Scotland, Centre for Environmental and
Ecological Modelling (CREEM). Methods and results are detailed in NODE
Reports covering all U.S. Atlantic coast OPAREAS as well as the Gulf of
Mexico.
Density estimates for cetaceans were derived in one of three ways, in order of preference: (1) Through spatial models using line-transect survey data provided by the NMFS (as discussed below); (2) using abundance estimates from Mullin and Fulling (2003); or (3) based on the cetacean abundance estimates found in the NMFS stock assessment reports
(SAR; Waring et al., 2007), which can be viewed at http:// www.nmfs.noaa.gov/pr/sars/species.htm. The following lists how density estimates were derived for each species:
Model-Derived Density Estimates
Fin whale, sperm whale, beaked whales, bottlenose dolphin, Atlantic spotted dolphin, striped dolphin, common dolphin, Risso's dolphin, and pilot whales.
SAR or Literature-Derived Density Estimates
North Atlantic right whale, humpback whale, minke whale, Kogia spp., rough-toothed dolphin, pantropical spotted dolphin, and Clymene dolphin.
Species for Which Density Estimates Are Not Available
Blue whale, sei whale, Bryde's whale, killer whale, pygmy killer whale, false killer whale, melon-headed whale, spinner dolphin,
Fraser's dolphin, harbor porpoise.
Spatial modeling using Program DISTANCE (RUWPA), a program based on
Buckland et al. (2001, 2004), is the primary method of density estimation used to produce the updated NODE reports. Together with appropriate line-transect survey data, this method provides the most accurate/up-to-date density information for marine mammals in U.S. Navy
OPAREAs. The density estimates in this document were calculated by a team of experts using survey data collected and provided by the NMFS and with expert modeling support provided by CREEM. Researchers at
CREEM are recognized as the international authority on density estimation and have been at the forefront in development of new techniques and analysis methods for animal density including spatial modeling techniques. Spatial modeling techniques have an advantage over traditional line-transect/distance sampling techniques in that they can provide relatively fine scale estimates for areas with limited or no available survey effort by creating models based on habitat parameters associated with observations from other surveys with similar spatial or temporal characteristics. Analysis of line-transect data in this manner allows for finer-scale spatial and/or temporal resolution of density estimates, providing indications of regions within the study area where higher and lower concentrations of marine mammals may occur rather than the traditional approach of generating a single estimate covering a broad spatial strata. These generic spatial strata tend to mask the finer scale habitat associations suggested by the specific ecology of an individual species.
For the model-based 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 (SST), and chlorophyll a concentration was formulated using generalized additive models (GAMs). This relationship was then used to generate a two-dimensional density surface for
Page 11056
the region by predicting densities in areas where no survey data exist.
For the Southeast, all analyses for cetaceans were based on sighting data collected through shipboard surveys conducted by the NMFS NEFSC and SEFSC between 1998 and 2005. Species-specific density estimates derived through spatial modeling were compared with abundance estimates found in the SAR (Waring et al., 2007) to ensure consistency and all spatial models and density estimates were reviewed by NMFS technical staff. For a more detailed description of the methodology involved in calculating the density estimates, please refer to the NODE report for the Southeast OPAREAs (DoN, 2007a).
Potential Impacts to Marine Mammal Species
The Navy considers that explosions associated with MISSILEX, FIREX with IMPASS, and MINEX are the activities with the potential to result in Level A or Level B harassment of marine mammals. Vessel strikes were also analyzed for potential effect to marine mammals.
Vessel Strikes
Collisions with commercial and Navy ships can result in serious injury and may occasionally cause fatalities to cetaceans and manatees.
Although the most vulnerable marine mammals may be assumed to be slow- moving cetaceans or those that spend extended periods of time at the surface in order to restore oxygen levels within their tissues after deep dives (e.g., sperm whale), fin whales are actually struck most frequently (Laist et al., 2001). Manatees are also particularly susceptible to vessel interactions and collisions with watercraft constitute the leading cause of mortality (USFWS, 2007). Smaller marine mammals such as bottlenose and Atlantic spotted dolphins move more 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 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 trans-Atlantic 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 human-related 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; followed by right whales, humpback whales, sperm whales, and gray whales (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, 2006).
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 mid-Atlantic 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. 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 2008,
NMFS published a final rule concerning right whale vessel collision reduction strategy and established operational measures for the shipping industry to reduce the potential for large vessel collisions with North Atlantic right whales while transiting to and from mid-
Atlantic ports during right whale migratory periods (73 FR 60173;
October 10, 2008). Although NMFS' ship strike rule does not apply to the Navy's activities, the Navy developed its own ship strike avoidance measures to reduce the probability of ship strikes. Recent studies of right whales have shown that these whales tend to lack a response to the sounds of oncoming vessels (Nowacek et al., 2004). 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' mid-Atlantic migratory corridor, the Navy was the first federal agency to proactively adopt additional mitigation measures for transits in the vicinity of mid-Atlantic ports during right whale migration.
Accordingly, the Navy has proposed mitigation measures to reduce the potential for collisions with surfaced marine mammals (for more details refer to Proposed Mitigation Measures 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 in 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., long-term effects or population consequences). The following is an assessment of marine mammal responses and disturbances when exposed to anthropogenic sound.
-
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
Page 11057
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 a 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 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 na[iuml]ve or experienced with the sound (i.e., what are the known/unknown consequences of the exposure).
If 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 non-auditory 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.
No tissue effects--The received sound is insufficient to cause either direct (mechanical) or indirect effects to tissues. No stress response occurs.
-
The Stress Response
The acoustic source is considered a potential stressor if, by its action on the animal, via auditory or non-auditory 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 hypothalamic-pituitary-adrenal (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
Page 11058
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 conditions of disease or injury). 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.
-
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.
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 disruption to a natural behavioral pattern (e.g., breeding or nursing) 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.
-
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, unit-level 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 by-products, 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). Non-lethal 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, the higher the level of impulse and pressure level
Page 11059
exposure, the more severe the impact to an individual.
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 gas-liquid interface
(Landsberg, 2000). Gas-containing organs, particularly the lungs and gastrointestinal tract, are especially susceptible (Goertner, 1982;
Hill, 1978; Yelverton et al., 1973). In addition, gas-containing 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). Sound-related 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 causing decreased sensitivity (Ketten, 1995) (See Assessment of
Marine Mammal Response to Anthropogenic Sound Section above). Sound- related 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 in this request include: FIREX with IMPASS, MISSILEX, and MINEX. Table 5 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 6 Hellfire events per year that can take place in sub-areas 16 and 17 during any season, so there are 1.5 events modeled for each season.
Table 5--Number of Explosive Events Within the Cherry Point Range Complex
Annual
Sub-area *
Ordnance
Winter
Spring
Summer
Fall
totals
MISSILEX.......................... ............ ............ ............ ............
22 16 & 17........................................ Hellfire..........................
1.5
1.5
1.5
1.5 ........... 16 & 17........................................ TOW...............................
2
2
2
2
...........
FIREX with IMPASS................. ............ ............ ............ ............
2 13 & 14........................................ 5rounds...............
.25
.25
.25
.25 ........... 4 & 5.......................................... 5rounds...............
.25
.25
.25
.25 ...........
MINEX............................. ............ ............ ............ ............
20
UNDET.......................................... 20 LB.............................
5
5
5
5
...........
* See Figure 1 of the LOA application for the location of sub-areas.
Definition of Harassment
As mentioned previously, with respect to military readiness activities, Section 3(18)(B) of the MMPA defines ``harassment'' as: (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].
Level B Harassment
Of the potential effects that were described in the Assessment of
Marine Mammal Response to Anthropogenic Sound and the Explosive
Ordnance Exposure Analysis sections, the following are the types of effects that fall into the Level B Harassment category:
Behavioral Harassment--Behavioral disturbance that rises to the level described in the definition above, when resulting from exposures to underwater detonations, is considered Level B Harassment. Some of the lower level physiological stress responses discussed in the
Assessment of Marine Mammal Response to Anthropogenic Sound section will also likely co-occur with the predicted harassments, although these responses are more difficult to detect and fewer data exist relating these responses to specific received levels of sound. When
Level B Harassment is predicted based on estimated behavioral responses, those takes may have a stress-related physiological component as well.
Acoustic Masking and Communication Impairment--Acoustic masking is considered Level B Harassment as it can disrupt natural behavioral patterns by interrupting or limiting the marine mammal's receipt or transmittal of important information or environmental cues.
TTS--As discussed previously, TTS can affect how an animal behaves in response to the environment, including conspecifics, predators, and prey. The following physiological mechanisms are thought to play a role in inducing auditory fatigue: 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. Ward (1997) suggested that when these effects result in
TTS rather than PTS, they are within the normal bounds of physiological variability and tolerance
Page 11060
and do not represent a physical injury. Additionally, Southall et al.
(2007) indicate that although PTS is a tissue injury, TTS is not because the reduced hearing sensitivity following exposure to intense sound results primarily from fatigue, not loss, of cochlear hair cells and supporting structures and is reversible. Accordingly, NMFS classifies TTS (when resulting from exposure to underwater detonations) as Level B Harassment, not Level A Harassment (injury).
Level A Harassment
Of the potential effects that were described in the Assessment of
Marine Mammal Response to Anthropogenic Sound section, the following are the types of effects that fall into the Level A Harassment category:
PTS--PTS is irreversible and considered to be an injury. PTS results from exposure to intense sounds that cause a permanent loss of inner or outer cochlear hair cells or exceed the elastic limits of certain tissues and membranes in the middle and inner ears and result in changes in the chemical composition of the inner ear fluids.
Physical Disruption of Tissues Resulting from Explosive Shock
Wave--Physical damage of tissues resulting from a shock wave (from an explosive detonation) is classified as an injury. Blast effects are greatest at the gas-liquid interface (Landsberg, 2000) and gas- containing organs, particularly the lungs and gastrointestinal tract, are especially susceptible to damage (Goertner, 1982; Hill 1978;
Yelverton et al., 1973). 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).
Severe damage (from the shock wave) to the ears can include tympanic membrane rupture, fracture of the ossicles, damage to the cochlea, hemorrhage, and cerebrospinal fluid leakage into the middle ear.
Acoustic Take Criteria
For the purposes of an MMPA incidental take authorization, three types of take are identified: Level B Harassment; Level A Harassment; and mortality (or serious injury leading to mortality). The categories of marine mammal responses (physiological and behavioral) that fall into the two harassment categories were described in the previous section.
Because the physiological and behavioral responses of the majority of the marine mammals exposed to underwater detonations cannot be detected or measured, a method is needed to estimate the number of individuals that will be taken, pursuant to the MMPA, based on the proposed action. To this end, NMFS uses an acoustic criteria that estimate at what received level (when exposed to explosive detonations)
Level B Harassment, Level A Harassment, and mortality (for explosives) of marine mammals would occur. The acoustic criteria for Underwater
Detonations are discussed.
Thresholds and Criteria for Impulsive Sound
Criteria and thresholds for estimating the exposures from a single explosive activity on marine mammals were established for the Seawolf
Submarine Shock Test Final Environmental Impact Statement (FEIS)
(``Seawolf'') and subsequently used in the USS Winston S. Churchill
(DDG-81) Ship Shock FEIS (``Churchill'') (DoN, 1998 and 2001a). NMFS adopted these criteria and thresholds in its final rule on unintentional taking of marine animals occurring incidental to the shock testing (NMFS, 2001a). Since the ship-shock events involve only one large explosive at a time, additional assumptions were made to extend the approach to cover multiple explosions for FIREX (with
IMPASS). In addition, this section reflects a revised acoustic criterion for small underwater explosions (i.e., 23 pounds per square inch [psi] instead of previous acoustic criteria of 12 psi for peak pressure over all exposures), which is based on the final rule issued to the Air Force by NMFS (NMFS, 2005c).
I.1. Thresholds and Criteria for Injurious Physiological Impacts
I.1.a. Single Explosion
For injury, NMFS uses dual criteria: eardrum rupture (i.e. tympanic-membrane injury) and onset of slight lung injury. These criteria are considered indicative of the onset of injury. The threshold for tympanic-membrane (TM) rupture corresponds to a 50 percent rate of rupture (i.e. 50 percent of animals exposed to the level are expected to suffer TM rupture). This value is stated in terms of an Energy Flux Density Level (EL) value of 1.17 inch pounds per square inch (in-lb/in2), approximately 205 dB re 1 microPa\2\-sec.
The threshold for onset of slight lung injury is calculated for a small animal (a dolphin calf weighing 26.9 lbs), and is given in terms of the ``Goertner modified positive impulse,'' indexed to 13 psi-msec
(DoN, 2001). This threshold is conservative since the positive impulse needed to cause injury is proportional to animal mass, and therefore, larger animals require a higher impulse to cause the onset of injury.
This analysis assumed the marine species populations were 100 percent small animals. The criterion with the largest potential impact range
(most conservative), either TM rupture (energy threshold) or onset of slight lung injury (peak pressure), will be used in the analysis to determine Level A exposures for single explosive events.
For mortality, NMFS uses the criterion corresponding to the onset of extensive lung injury. This is conservative in that it corresponds to a 1 percent chance of mortal injury, and yet any animal experiencing onset severe lung injury is counted as a lethal exposure. For small animals, the threshold is given in terms of the Goertner modified positive impulse, indexed to 30.5 psi-msec. Since the Goertner approach depends on propagation, source/animal depths, and animal mass in a complex way, the actual impulse value corresponding to the 30.5 psi- msec index is a complicated calculation. To be conservative, the analysis used the mass of a calf dolphin (at 26.9 lbs) for 100 percent of the populations.
I.1.b. Multiple Explosions
For this analysis, the use of multiple explosions only applies to
FIREX (with IMPASS). Since FIREX require multiple explosions, the
Churchill approach had to be extended to cover multiple sound events at the same training site. For multiple exposures, accumulated energy over the entire training time is the natural extension for energy thresholds since energy accumulates with each subsequent shot (detonation); this is consistent with the treatment of multiple arrivals in Churchill. For positive impulse, it is consistent with Churchill to use the maximum value over all impulses received.
I.2. Thresholds and Criteria for Non-Injurious Physiological Effects
The NMFS' criterion for non-injurious harassment is TTS--a slight, recoverable loss of hearing sensitivity (DoN, 2001). For this assessment, there are dual criteria for TTS, an energy threshold and a peak pressure threshold. The criterion with the largest potential impact range (most conservative) either the energy or peak pressure threshold, will be used in the analysis to determine Level B TTS exposures.
I.2.a. Single Explosion--TTS-Energy Threshold
The first threshold is a 182 dB re 1 microPa\2\-sec maximum energy flux
Page 11061
density level in any \1/3\-octave band at frequencies above 100 Hertz
(Hz) for toothed whales and in any \1/3\-octave band above 10 Hz for baleen whales. For large explosives, as in the case of the Churchill
FEIS, frequency range cutoffs at 10 and 100 Hz make a difference in the range estimates. For small explosives ( 100 Hz for toothed whales and > 10 Hz for baleen whales)-- for total energy over all exposures.
Non-injurious Physiological.... TTS............... Peak pressure over 23 psi............ Level B. all exposures.
Page 11062
Non-injurious Behavioral....... Multiple
Greatest energy
177 dB re 1
Level B.
Explosions
flux density
microPa\2\-sec.
Without TTS.
level in any \1/ 3\-octave (> 100
Hz for toothed whales and > 10
Hz for baleen whales)--for total energy over all exposures
(multiple explosions only).
The criteria for mortality, Level A Harassment, and Level B
Harassment resulting from explosive detonations were initially developed for the Navy's Sea Wolf and Churchill ship-shock trials and have not changed since other MMPA authorizations issued for explosive detonations. The criteria, which are applied to cetaceans and pinnipeds are summarized in Table 11. Additional information regarding the derivation of these criteria is available in the Navy's FEIS for the
Cherry Point Range Complex and in the Navy's CHURCHILL FEIS (U.S.
Department of the Navy, 2001).
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 geo-acoustic 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 Geo-acoustics--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 summarized for each major type of exercise. A more in-depth effects analysis is in Appendix A of the LOA application and the Addendum. 1. FIREX (With IMPASS)
Modeling was completed for a 5-in. round, 8-lb NEW charge exploding at a depth of 1 ft (0.3 m). The analytical approach begins using a high-fidelity acoustic model to estimate energy in each 5-in 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 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 39-shot event is calculated as the sum of small impact areas for seven FIREX missions (each with four to six rounds fired) and one pre-FIREX action (with six rounds fired). Table 7 shows the Zone of Influence (ZOI) results of the model estimation.
Table 7--Estimated ZOIs (km\2\) for a Single FIREX (With IMPASS) Event
Estimated ZOI @
Estimated ZOI @ 177 dB re 1 Estimated ZOI @
205 dB re 1
Area *
muPa\2\-sec (multiple
23 psi
muPa\2\-sec or detonations only)
13 psi
4 & 5....................................... NA **.........................
3.7387
0.18522 13 & 14..................................... NA **.........................
3.7387
0.18522
* Please see Figure 1 of the LOA application for the locations of these areas.
** In this area, which occurs in deeper water, the 23 psi 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 5), provides the exposure estimates for that animal species for the nominal exercise case of 39 5-in explosive rounds. The potential effects would occur within a series of small impact areas associated with the pre-calibration 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 two locations in the Cherry
Point Range Complex. In addition to other mitigation measures, dedicated lookouts would be onboard the ship monitoring the target area for marine mammals before the exercise, during the deployment of the
IMPASS array, and during the return to firing position. Ships will not fire on the target until the area is cleared and will suspend the exercise if any marine mammals enter the buffer area. Due to safety reasons, the buffer zone must remain clear of all types of platforms.
During the actual firing of the weapon, the participants involved must be able
Page 11063
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 the distance between the firing position and the buffer zone, lookouts are only expected to visually detect breaching whales, whale blows, and large pods of dolphins and porpoises. Implementation of mitigation measures like these reduce the likelihood of exposure and potential effects in the
ZOI. 2. MINEX
The Comprehensive Acoustic System Simulation/Gaussian Ray Bundle
(OAML, 2002) model, modified to account for impulse response, shock- wave waveform, and nonlinear shock-wave effects, was run for acoustic- environmental 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/
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 TTS-energy criterion (182 dB re 1 microPa\2\-sec) was dominant over the pressure criteria and therefore used to determine the
ZOI for the Level B exposure analysis. Table 8 shows the ZOI results of the model estimation.
The total ZOI, when multiplied by the animal densities and total number of events (Table 5), 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.
The underwater detonations are restricted to one area (UNDET Area,
Onslow Bay) (Figure 1 of the LOA application), observers would survey the target area for marine mammals for 30 minutes prior through 30 minutes post detonation. 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.
Table 8--Estimated ZOIs (km\2\) for MINEX
ZOIs
Threshold
20-lb shot
Level A ZOI @ 13 psi................... 0.13 km\2\ 10%
Level B ZOI @ 182 dB re 1 microPa\2\- 0.8 km\2\ 25% sec.
-
MISSILEX (Hellfire and TOW)
Modeling was completed for three explosive missiles involved in
MISSILEX: each assumed detonation at 1-m (3.3 ft) depth. The NEW used in simulations of the Hellfire and TOW missiles are 8 lbs and 15.33 lbs, respectively. The single explosion TTS-energy criterion (182 dB re 1 microPa\2\-sec) was used to determine the ZOI for the Level B exposure analysis. Table 9 shows the ZOI results of the model estimation. The total ZOI, when multiplied by the animal densities and total number of events (Table 5), provides the exposure estimates for that animal species for each specified missile. 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.
Ships will not fire on the target until the area is clear of marine mammals, and will suspend the exercise if any enter the buffer area.
Implementation of mitigation measures like these reduce the likelihood of exposure and potential effects in the ZOI.
Table 9--Estimated ZOIs (km\2\) for MISSILEX
Estimated ZOI @ 182 dB re 1
Estimated ZOI @ 205 dB re 1
Estimated ZOI @ 30.5 psi microPa2-s or 23 psi
microPa2-s or 13 psi
-------------------------------
Area
Ordnance
----------------------------------------------------------------
Win
Spr
Sum
Fall
Win
Spr
Sum
Fall
Win
Spr
Sum
Fall
16 & 17........................... Hellfire............ 0.31 0.31 0.31 0.31 0.04 0.04 0.04 0.04 Results from the Navy's monitoring from the previous year
(either from the Cherry Point Range Complex or other locations)
Compiled results of Navy funded research and development
(R&D) studies (presented pursuant to the ICMP, which is discussed elsewhere in this document)
Results from general marine mammal and sound research
(funded by the Navy [described below] or otherwise)
Any information which reveals that marine mammals may have been taken in a manner, extent or number not authorized by these regulations or subsequent Letters of Authorization.
Mitigation measures could be modified or added if new data suggests that such modifications would have a reasonable likelihood of accomplishing the goals of mitigation laid out in this proposed rule and if the measures are practicable. NMFS would also coordinate with the Navy to modify or add to the existing monitoring requirements if the new data suggest that the addition of a particular measure would more effectively accomplish the goals of monitoring laid out in this proposed rule. The reporting requirements associated with this rule are designed to provide NMFS with monitoring data from the previous year to allow NMFS to consider the data in issuing annual LOAs. NMFS and the
Navy will meet annually prior to LOA issuance to discuss the monitoring reports, Navy R&D developments, and current science and whether mitigation or monitoring modifications are appropriate.
Monitoring and Reporting Measures
In order to issue an ITA for an activity, Section 101(a)(5)(A) of the MMPA states that NMFS must set forth ``requirements pertaining to the monitoring and reporting of such taking.'' The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for LOAs must include the suggested means of accomplishing the necessary monitoring and reporting that will result in increased knowledge of the species and of the level of taking or impacts on populations of marine mammals that are expected to be present.
Monitoring measures prescribed by NMFS should accomplish one or more of the following general goals: a. An increase in the probability of detecting marine mammals, both within the safety zone (thus allowing for more effective implementation of the mitigation) and in general to generate more data to contribute to the effects analyses. b. An increase in our understanding of how many marine mammals are likely to be exposed to levels of explosives or other stimuli that we associate with specific adverse effects, such as behavioral harassment,
TTS, or PTS. c. An increase in our understanding of how marine mammals respond
(behaviorally or physiologically) to explosives or other stimuli expected to result in take and how anticipated adverse effects on individuals (in different ways and to varying degrees) may impact the population, species, or stock (specifically through effects on annual rates of recruitment or survival). d. An increased knowledge of the affected species. e. An increase in our understanding of the effectiveness of certain mitigation and monitoring measures. f. A better understanding and record of the manner in which the authorized entity complies with the incidental take authorization.
The Navy would be required to cooperate with the NMFS when monitoring the impacts of the activity on marine mammals.
The Navy must notify NMFS immediately (or as soon as clearance procedures allow) if the specified activity is thought to have resulted in the mortality or injury of any marine mammals, or in any take of marine mammals not identified in this document.
The Navy must conduct all monitoring and/or research required under the Letter of Authorization, if issued.
The monitoring methods proposed for use during training events in the Cherry Point Range Complex include a combination of individual elements designed to allow a comprehensive assessment include: 1. Vessel and aerial surveys. i. Visual surveillance of 1 event per year. If possible, the event surveyed will be one involving multiple detonations. Due to the limited number of events conducted in the Cherry Point Range Complex, there is a potential that it may be impossible to coordinate required surveys to take place during the limited opportunities presented. In any case, any missed annual survey requirement will roll into the subsequent year ensuring that the appropriate number of surveys occur over the 5-year regulations. Likewise, additional surveys may be scheduled in any year where additional opportunities arise, with the number of surveys during the 5-year regulations not to exceed 5. ii. For surveyed training events, aerial or vessel surveys will be used 1-2 days prior to, during (if safe to do so), and 1-5 days post detonation. The variation in the number of days after allows for the detection of animals that gradually return to an area, if they indeed do change their distribution in response to underwater detonation events. iii. Surveys will include any specified exclusion zone around a particular detonation point plus 2,000 yards beyond the border of the exclusion zone (i.e., the circumference of the area from the border of the exclusion zone extending 2,000 yards outwards). The survey shall be conducted using a towed array behind the survey vessel in transect lines or grid in the predetermined area outside the exclusion zone and should be conducted in a manner that ensures the entire circumference of the exclusion zone can be observed. For vessel-based surveys a passive acoustic system (hydrophone or towed array) could be used to determine if marine mammals are in the area before and/or after a detonation event. Depending on animals sighted, it may be possible to conduct focal surveys of animals outside of the exclusion zone
(detonations could be delayed if marine mammals are observed within the exclusion zone) to record behavioral responses to the detonations. iv. When conducting a particular survey, the survey team will collect:
A. Species identification and group size;
B. Location and relative distance from the detonation site;
Page 11070
C. The behavior of marine mammals including standard environmental and oceanographic parameters;
D. Date, time and visual conditions associated with each observation;
E. Direction of travel relative to the detonation site; and
F. Duration of the observation. 2. Passive acoustic monitoring. i. When practicable, a towed hydrophone array should be used whenever shipboard surveys are being conducted. The towed array would be deployed during daylight hours for each of the days the ship is at sea. ii. A towed hydrophone array is towed from the boat and can detect and localize marine mammals that vocalize and would be used to supplement the ship-based systematic line-transect surveys
(particularly for species such as beaked whales that are rarely seen). iii. The array would need to detect low frequency vocalizations (
-
