Taking of Marine Mammals Incidental to Specified Activities; U.S. Marine Corps Training Exercises at Air Station Cherry Point, 71535-71554 [2011-29851]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 223 (Friday, November 18, 2011)]
[Notices]
[Pages 71535-71554]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-29851]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA800


Taking of Marine Mammals Incidental to Specified Activities; U.S. 
Marine Corps Training Exercises at Air Station Cherry Point

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

-----------------------------------------------------------------------

SUMMARY: NMFS has received an application from the U.S. Marine Corps 
(USMC) requesting authorization to take marine mammals incidental to 
various training exercises at Marine Corps Air Station (MCAS) Cherry 
Point Range Complex, North Carolina. The USMC's activities are 
considered military readiness activities pursuant to the Marine Mammal 
Protection Act (MMPA), as amended by the National Defense Authorization 
Act (NDAA) for Fiscal Year 2004. Pursuant to the MMPA, NMFS is 
requesting comments on its proposal to issue an incidental harassment 
authorization (IHA) to the USMC to take bottlenose dolphins (Tursiops 
truncatus), by Level B harassment only, from specified activities.

DATES: Comments and information must be received no later than December 
19, 2011.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Permits and Conservation Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910-3225. The mailbox address for providing email 
comments is ITP.Laws@noaa.gov. NMFS is not responsible for email 
comments sent to addresses other than the one provided here. Comments 
sent via email, including all attachments, must not exceed a 10-
megabyte file size.
    Instructions: All comments received are a part of the public record 
and may be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm 
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.
    A copy of the application containing a list of the references used 
in this

[[Page 71536]]

document may be obtained by writing to the address specified above, 
telephoning the contact listed below (see FOR FURTHER INFORMATION 
CONTACT), or visiting the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. The following associated document is also 
available at the same Internet address: Environmental Assessment MCAS 
Cherry Point Range Operations (USMC 2009). Documents cited in this 
notice may also be viewed, by appointment, during regular business 
hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) of the MMPA (16 U.S.C. 1361 et seq.) direct 
the Secretary of Commerce 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) 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 for incidental takings may 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 certain 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.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of 
an application followed by a 30-day public notice and comment period on 
any proposed authorizations for the incidental harassment of marine 
mammals. Within 45 days of the close of the comment period, NMFS must 
either issue or deny the authorization.
    The NDAA (Pub. L. 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 September 22, 2011, NMFS received an application from the USMC 
requesting an IHA for the harassment of Atlantic bottlenose dolphins 
(Tursiops truncatus) incidental to air-to-surface and surface-to-
surface training exercises conducted around two bombing targets (BTs) 
within southern Pamlico Sound, North Carolina, at MCAS Cherry Point. 
NMFS first issued an IHA to the USMC for the same activities that was 
valid for a period of one year, beginning December 1, 2011 (75 FR 
72807; November 26, 2010).
    Weapon delivery training would occur at two BTs: Brant Island 
Target (BT-9) and Piney Island Bombing Range (BT-11). Training at BT-9 
would involve air-to-surface (from aircraft to in-water targets) and 
surface-to-surface (from vessels to in-water targets) warfare training, 
including bombing, strafing, special (laser systems) weapons; surface 
fires using non-explosive and explosive ordnance; and mine laying 
exercises (inert). Training at BT-11 would involve air- to-surface 
exercises to provide training in the delivery of conventional (non-
explosive) and special (laser systems) weapons. Surface-to-surface 
training by small military watercraft would also be executed here. The 
types of ordnances proposed for use at BT-9 and BT-11 include small 
arms, large arms, bombs, rockets, missiles, and pyrotechnics. All 
munitions used at BT-11 are inert, practice rounds. No live firing 
occurs at BT-11. Training for any activity may occur year-round. Active 
sonar is not a component of these specified training exercises; 
therefore, discussion of marine mammal harassment from active sonar 
operations is not included within this notice.

Description of the Specified Activity

    The USMC is requesting authorization to harass bottlenose dolphins 
from ammunition firing conducted at two BTs within MCAS Cherry Point. 
The authorization would be valid for a period of one year from the date 
of issuance. The BTs are located at the convergence of the Neuse River 
and Pamlico Sound, North Carolina. BT-9 is a water-based target located 
approximately 52 km (28 nautical miles [nm]) northeast of MCAS Cherry 
Point. The BT-9 target area ranges in depth from 1.2 m to 6.1 m, with 
the shallow areas concentrated along the Brandt Island Shoal (which 
runs down the middle of the restricted area in a northwest to southeast 
orientation). The target itself consists of three ship hulls grounded 
on Brant Island Shoals, located approximately 4.8 km (3 miles [mi]) 
southeast of Goose Creek Island. Inert (non-explosive) ordnance up to 
454 kilograms (kg) (1,000 lbs) and live (explosive) ordnance up to 45.4 
kg (100 lbs) TNT equivalent, including ordnance released during 
strafing, are authorized for use at this target range. The target is 
defined by a 6 statute-mile (SM) diameter prohibited area designated by 
the U.S. Army Corps of Engineers, Wilmington District (33 CFR 334.420). 
Non-military vessels are not permitted within the prohibited area, 
which is delineated by large signs located on pilings surrounding the 
perimeter of the BT. BT-9 also provides a mining exercise area; 
however, all mine exercises are simulation only and do not involve 
detonations. BT-9 standard operating procedures limit live ordnance 
deliveries to a maximum explosive weight of 100 lbs TNT equivalent. The 
USMC estimates that it would conduct approximately 1,539 aircraft-based 
and 165 vessel-based sorties, annually, at BT-9. The standard sortie 
consists of two aircraft per bombing run or an average of two and 
maximum of six vessels.
    BT-11 is a 50.6 square kilometers (sq km) (19.5 square miles [sq 
mi]) complex of land- and water-based targets on Piney Island. The BT-
11 target area ranges in depth from 0.3 m along the shoreline to 3.1 m 
in the center of Rattan Bay (BA 2001). The in-water stationary targets 
of BT-11 consist of a barge and patrol (PT) boat located in roughly the 
center of Rattan Bay. The barge target is approximately 135 ft by 40 ft 
in dimension. The PT boat is approximately 110 ft by 35 ft in 
dimension. Water depths in the center of Rattan Bay are estimated as 
2.4 to 3 m (8 to 10 ft) with bottom depths ranging from 0.3 to 1.5 m (1 
to 5 ft) adjacent to the shoreline of Piney Island. A shallow ledge, 
with substrate expected to be hard-packed to hard bottom, surrounds 
Piney Island. No live firing occurs at BT-11; all munitions used are 
inert,

[[Page 71537]]

non-explosive practice rounds. Only 36 percent of all munitions fired 
at BT-11 occur over water; the remaining munitions are fired to land 
based targets on Piney Island. The USMC estimates that it would conduct 
approximately 6,727 aircraft-based and 51 vessel-based sorties, 
annually, at BT-11.
    All inert and live-fire exercises at MCAS Cherry Point ranges are 
conducted so that all ammunition and other ordnances strike and/or fall 
on the land or water based target or within the existing danger zones 
or water restricted areas. A danger zone is a defined water area that 
is closed to the public on an intermittent or full-time basis for use 
by military forces for hazardous operations such as target practice and 
ordnance firing. A water restricted area is a defined water area where 
public access is prohibited or limited in order to provide security for 
Government property and/or to protect the public from the risks of 
injury or damage that could occur from the government's use of that 
area (33 CFR 334.2). Surface danger zones are designated areas of 
rocket firing, target practice, or other hazardous operations (33 CFR 
334.420). The surface danger zone (prohibited area) for BT-9 is a 4.8 
km radius centered on the south side of Brant Island Shoal. The surface 
danger zone for BT-11 is a 2.9 km radius centered on a barge target in 
Rattan Bay.
    According to the application, the USMC is requesting take of marine 
mammals incidental to specified activities at MCAS Cherry Point Range 
Complex, located within Pamlico Sound, North Carolina. These activities 
include gunnery; mine laying; bombing; or rocket exercises and are 
classified into two categories here based on delivery method: (1) 
Surface-to-surface gunnery and (2) air-to-surface bombing. Exercises 
may occur year round, day or night (approximately 15 percent of 
training occurs at night).

Surface-to-Surface Gunnery Exercises

    Surface-to-surface fires are fires from boats at sea to targets at 
sea. These can be direct (targets are within sight) or indirect 
(targets are not within sight). Gunnery exercise employing only direct 
fire is the only category of surface-to-surface activity currently 
conducted within the MCAS Cherry Point BTs. An average of two and 
maximum of six small boats (24-85 ft), or fleet of boats, typically 
operated by Special Boat Team personnel, use a machine gun to attack 
and disable or destroy a surface target that simulates another ship, 
boat, swimmer, floating mine or near shore land targets. Vessels travel 
between 0-20 kts with an average of two vessels actually conducting 
surface-to-surface firing activities. Typical munitions are 7.62 
millimeter (mm) or .50 caliber (cal) machine guns; and/or 40 mm Grenade 
machine guns. This exercise is usually a live-fire exercise, but at 
times blanks may be used so that the boat crews can practice their ship 
handling skills. The goal of training is to hit the targets; however, 
some munitions may bounce off the targets and land in the water or miss 
the target entirely. Additionally, G911 Concussion hand grenades (inert 
and live) are used; however, these are not aimed at targets, as the 
goal is to learn how to throw them into the water.
    The estimated amount of munitions expended at BT-9 and BT-11 during 
this training can be found in Table 1 below. Historically, boat sorties 
have been conducted at BT-9 and BT-11 year round with equal 
distribution of training effort throughout the seasons. Live fires 
constitute approximately 90 percent of all surface-to-surface gunnery 
events. The majority of sorties originated and practiced at BT-9 as no 
live fire is conducted at BT-11. The USMC has indicated a comparable 
number of sorties would occur throughout the IHA timeframe. There is no 
specific schedule associated with the use of ranges by the small boat 
teams. However, exercises tend to be scheduled for 5-day blocks with 
exercises at various times throughout that timeframe. There is no 
specific time of year or month training occurs as variables such as 
deployment status, range availability, and completion of crew specific 
training requirements influence schedules.
    A number of different types of boats are used during surface-to-
surface exercises depending on the unit using the boat and their 
mission and include versions of Small Unit River Craft, Combat Rubber 
Raiding Craft, Rigid Hull Inflatable Boats, Patrol Craft. They are 
inboard or outboard, diesel or gasoline engines with either propeller 
or water jet propulsion. Boat crews approach, at a maximum of 20 kts, 
and engage targets simulating other boats, swimmers, floating mines, or 
near shore land targets with 7.62 mm or .50 cal machine guns; 40 mm 
grenade machine guns; or M3A2 Concussion hand grenades (approximately 
200, 800, 10, and 10 rounds respectively). Vessels typically travel in 
linear paths and do not operate erratically. Other vessels may be 
located within the BTs; however, these are support craft and do not 
participate in munitions expenditures. The purpose of the support craft 
is to remotely control High Speed Maneuvering Surface Targets (HSMSTs) 
or to conduct maintenance on electronic equipment located in the towers 
at BT-9. Support craft are typically anchored or tied to marker pilings 
during HSMST operations or tied to equipment towers. When underway, 
vessels do not typically travel faster than 12-18 kts or in an erratic 
manner.

      Table 1--Type and Amount of Munitions Expended at BT-9 and BT-11 During Surface-to-Surface Exercises
----------------------------------------------------------------------------------------------------------------
                                                                                                    Munitions
                   Range                     Annual number             Munitions type                expended
                                             of sorties \1\                                          annually
----------------------------------------------------------------------------------------------------------------
BT-9......................................              165  5.56 mm...........................            1,468
                                            ...............  7.62 mm...........................          218,500
                                            ...............  .50 cal...........................          166,900
                                            ...............  40 mm Grenade--Inert..............           15,734
                                            ...............  40 mm Grenade--Live (HE)..........            9,472
                                            ...............  G911 Grenade......................              144
BT-11.....................................               51  7.62 mm...........................           44,100
                                            ...............  .40 cal...........................            4,600
                                            ...............  40 mm Grenade--Inert..............            1,517
                                            ...............  40 mm Illumination-Inert..........                9
----------------------------------------------------------------------------------------------------------------
\1\ Sorties are from FY 2007 CURRS data.


[[Page 71538]]

Air-to-Surface

    Air-to-surface training involves ordnance delivered from aircraft 
and aimed at targets on the water's surface or on land in the case of 
BT-11. A description of the types of targets used at MCAS Cherry Point 
is provided in the section on BTs above. There are four types of air-
to-surface activities conducted within the MCAS Cherry Point BTs: Mine 
laying; bombing; gunnery or rocket exercises which are carried out via 
fixed wing or rotary wing aircraft.

Mine Laying Exercises

    Mine Warfare (MIW) includes the strategic, operational, and 
tactical use of mines and mine countermine measures. MIW is divided 
into two basic subdivisions: (a) 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, 2007). MCAS Cherry Point would only 
engage in mine laying exercises as described below. No detonations of 
any mine device are involved with this training.
    During mine laying, a fixed-wing or maritime patrol aircraft (P-3 
or P-8) typically drops a series of about four inert mine shapes in an 
offensive or defensive pattern, making multiple passes along a pre-
determined flight azimuth, and dropping one or more shapes each time. 
Mine simulation shapes include MK76, MK80 series, and BDU practice 
bombs ranging from 25 to 2,000 pounds in weight, There is an attempt to 
fly undetected to the area where the mines are laid with either a low 
or high altitude tactic flight. The shapes are scored for accuracy as 
they enter the water and the aircrew is later debriefed on their 
performance. The training shapes are inert (no detonations occur) and 
expendable. Mine laying operations are regularly conducted in the water 
in the vicinity of BT-9.

Bombing Exercises

    The purpose of bombing exercises is to train pilots in destroying 
or disabling enemy ships or boats. During training, fixed wing or 
rotary wing aircraft deliver bombs against surface maritime targets at 
BT-9 or BT-11, day or night, using either unguided or precision-guided 
munitions. Unguided munitions include MK-76 and BDU-45 inert training 
bombs, and MK-80 series of inert bombs (no cluster munitions 
authorized). Precision-guided munitions consist of laser-guided bombs 
(inert) and laser-guided training rounds (inert). Typically, two 
aircraft approach the target (principally BT-9) from an altitude of 
approximately 914 m (3,000 ft) up to 4,572 m (15,000 ft) and, when on 
an established range, the aircraft adhere to designated ingress and 
egress routes. Typical bomb release altitude is 914 m (3,000 ft) for 
unguided munitions or above 4,572 m (15,000 ft) and in excess of 1.8 km 
(1 nm) for precision-guided munitions. However, the lowest minimum 
altitude for ordnance delivery (inert bombs) would be 152 m (500 ft).
    Onboard laser designators or laser designators from a support 
aircraft or ground support personnel are used to illuminate certified 
targets for use when using laser guided weapons. Due to target 
maintenance issues, live bombs have not been dropped at the BT-9 
targets for the past few years although these munitions are authorized 
for use. For the effective IHA timeframe, no live bombs would be 
utilized. Live rockets and grenades; however, have been expended at BT-
9.
    Air-to-Surface bombing exercises have the potential to occur on a 
daily basis. The standard sortie consists of two aircraft per bombing 
run. The frequency of these exercises is dependent on squadron level 
training requirements, deployment status, and range availability; 
therefore, there is no set pattern or specific time of year or month 
when this training occurs. Normal operating hours for the range are 
0800-2300, Monday through Friday; however, the range is available for 
use 365 days per year.

Rocket Exercises

    Rocket exercises are carried out similar to bombing exercises. 
Fixed- and rotary-wing aircraft crews launch rockets at surface 
maritime targets, day and night, to train for destroying or disabling 
enemy ships or boats. These operations employ 2.75-inch and 5-inch 
rockets.
    The average number of rockets delivered per sortie is approximately 
14. As with the bombing exercise, there is no set level or pattern of 
amount of sorties conducted.

Gunnery Exercises

    During gunnery training, fixed- and rotary-wing aircraft expend 
smaller munitions targeted at the BTs with the purpose of hitting them. 
However, some small arms may land in the water. Rotary wing exercises 
involve either CH-53, UH-1, CH-46, MV-22, or H-60 rotary-wing aircraft 
with mounted 7.62 mm or .50 cal machine guns. Each gunner expends 
approximately 800 rounds of 7.62 mm and 200 rounds of .50 cal 
ammunition in each exercise. These may be live or inert.
    Fixed wing gunnery exercises involve the flight of two aircraft 
that begin to descend to the target from an altitude of approximately 
914 meters (m) (3,000 feet [ft]) while still several miles away. Within 
a distance of 1,219 m (4,000 ft) from the target, each aircraft fires a 
burst of approximately 30 rounds before reaching an altitude of 305 m 
(1,000 ft), then breaks off and repositions for another strafing run 
until each aircraft expends its exercise ordnance allowance of 
approximately 250 rounds. In total, about 8-12 passes are made by each 
aircraft per exercise. Typically these fixed wing exercise events 
involve an F/A-18 and AH-1 with Vulcan M61A1/A2, 20 mm cannon; AV-8 
with GAU-12, 25 mm cannon.

Munition Descriptions

    A complete list of the ordnance authorized for use at BT-9 and BT-
11 can be found in Tables 2 and 3, respectively. There are several 
varieties and net explosive weights (for live munition used at BT-9) 
can vary according to the variety. All practice bombs are inert and 
used to simulate the same ballistic properties of service type bombs. 
They are manufactured as either solid cast metal bodies or thin sheet 
metal containers. Since practice bombs contain no explosive filler, a 
practice bomb signal cartridge (smoke) is used for visual observation 
of weapon target impact. Practice bombs provide a low cost training 
device for pilot and ground handling crews. Due to the relatively small 
amount of explosive material in practice bombs (small signal charge), 
the availability of ranges for training is greatly increased.
    When a high explosive detonates, it is converted almost instantly 
into a gas at very high pressure and temperature. Under the pressure of 
the gases thus generated, the weapon case expands and breaks into 
fragments. The air surrounding the casing is compressed and shock 
(blast) wave is transmitted into it. Typical initial values for a high-
explosive weapon are 200 kilobars of pressure (1 bar = 1 atmosphere) 
and 5,000 degrees Celsius. There are five types of explosive sources 
used at BT-9: 2.75'' Rocket High Explosives, 5'' Rocket High 
Explosives, 30 mm High Explosives, 40 mm High Explosives, and G911 
grenades. No live munitions are used at BT-11.

[[Page 71539]]



             Table 2--Description of Munitions Used at BT-9
------------------------------------------------------------------------
                                                          Net explosive
           Ordnance                   Description            weight
------------------------------------------------------------------------
MK76 Practice Bomb (inert)....  25-pound teardrop-      (of signal
                                 shaped cast metal       cartridge)
                                 bomb, with a bore       varies, maximum
                                 tube for installation   0.083800 lbs.
                                 of a signal cartridge.
BDU 33 Practice Bomb (inert)..  Air Force MK 76         same as above.
                                 practice bomb.
BDU 48 Practice Bomb (inert)..  10-pound metal          same as above.
                                 cylindrical bomb body
                                 with a bore tube for
                                 installation of a
                                 signal cartridge.
BDU 45 Practice Bomb (inert)..  500-pound metal bomb    (of signal
                                 either sand or water    cartridges,
                                 filled. Two signal      total 0.1676
                                 cartridges.             lbs.
BDU 50 Practice Bomb (inert)..  500-pound metal bomb    same as above.
                                 either sand or water
                                 filled. Two signal
                                 cartridges.
MK 81 Practice Bomb (inert)...  250-pound bomb........  0.
MK 82 Practice Bomb (inert)...  500-pound bomb........  0.
MK 83 Practice Bomb (inert)...  1000-pound bomb         0.1676 lbs.
                                 configured like BDU
                                 45.
MK 84 Practice Bomb (inert)     2000-pound bomb         0.1676 lbs.
 (special exception use only).   configured like BDU
                                 45.
2.75-inch (inert).............  Unguided 2.75-inch      0.
                                 diameter rocket.
5-inch Zuni (inert)...........  Unguided 5-inch         0.
                                 diameter rocket.
5-inch Zuni (live)............  Unguided 5-inch         15 lbs.
                                 diameter rocket.
2.75wp (inert)................  2.75-inch rocket        0.
                                 containing white
                                 phosphorous.
2.75HE........................  High Explosive, 2.75-   4.8 lbs.
                                 inch rocket.
0.50 cal (inert)..............  Machine gun rounds....  0.
7.62 mm (inert)
20 mm (inert)
25mm (inert)
30 mm (inert)
40 mm (inert)
25 mm HE (live)...............  High Explosive          0.269 lbs.
                                 Incendiary, Live
                                 machine gun rounds.
Self Protection Flare.........  Aerial flare..........  0.
Chaff.........................  18-pound chaff          0.
                                 canister.
LUU-2.........................  30-pound high           0.
                                 intensity
                                 illumination flare.
Laser Guided Training Round     89-pound inert          0.
 (LGTR) (inert).                 training bomblet.
------------------------------------------------------------------------


             Table 3--Description of Munitions Used at BT-11
------------------------------------------------------------------------
                Ordnance                           Description
------------------------------------------------------------------------
MK76 Practice Bomb.....................  25-pound teardrop-shaped cast
                                          metal bomb body, with a bore
                                          tube for installation of a
                                          signal cartridge.
BDU 33 Practice Bomb...................  Air Force designation for MK 76
                                          practice bomb.
BDU 48 Practice Bomb...................  10-pound metal cylindrical bomb
                                          body with a bore tube for
                                          installation of a signal
                                          cartridge.
BDU45 Practice Bomb....................  500-pound metal bomb body
                                          either sand or water filled.
                                          Configured with either low
                                          drag conical tail fins or high
                                          drag tail fins for retarded
                                          weapons delivery. Two signal
                                          cartridges installed.
MK 81 Practice Bomb....................  250-pound inert bomb.
MK 82 Practice Bomb....................  500-pound inert bomb.
2.75-inch..............................  Unguided 2.75 inch diameter
                                          rocket.
5-inch Zuni............................  5 inch diameter rocket.
WP-2.75-inch...........................  White phosphorous 7-pound
                                          rocket.
0.50 cal...............................  Inert machine gun rounds
7.62 mm
5.56 mm
20 mm
30 mm
40 mm
TOW....................................  Wire guided 56-pound anti-tank
                                          missile.
Self Protection Flare..................  Aerial flare.
SMD SAMS...............................  1.5-pound smoking flare.
LUU-2..................................  30-pound high-intensity
                                          illumination flare.
Laser Guided Training Round (LGTR).....  89-pound inert training
                                          bomblet.
------------------------------------------------------------------------

     The amounts of all ordnance to be expended at BT-9 and BT-11 (both 
surface-to-surface and air-to-surface) are 897,932 and 1,109,955 
rounds, respectively (see Table 4 and 5 below).

[[Page 71540]]



                      Table 4--Amount of Live and Inert Munitions Expended at BT-9 Per Year
----------------------------------------------------------------------------------------------------------------
                                                                 Proposed number of explosive
           Proposed munitions \1\              Proposed total   rounds having an impact on the    Net explosive
                                              number of rounds               water                 weight (lb)
----------------------------------------------------------------------------------------------------------------
Small Arms Rounds Excluding .50 cal.........           525,610  N/A...........................               N/A
.50 Cal.....................................           257,067  N/A...........................               N/A
Large Arms Rounds--Live.....................            12,592  30mm HE: 3,120................            0.1019
                                                                40mm HE: 9,472................            0.1199
Large Arms Rounds--Inert....................            93,024  N/A...........................               N/A
Rockets--Live...............................               241  2.75'' Rocket: 184............               4.8
                                                                5'' Rocket: 57................              15.0
Rockets--Inert..............................               703  N/A...........................               N/A
Bombs and Grenades--Live....................               144  G911 Grenade: 144.............               0.5
Bombs and Grenades--Inert...................             4,055  N/A...........................               N/A
Pyrotechnics................................             4,496  N/A...........................               N/A
                                             -------------------------------------------------------------------
    Total...................................           897,932  12,977........................               N/A
----------------------------------------------------------------------------------------------------------------
\1\ Munitions may be expended from aircraft or small boats.


          Table 5--Amount of Inert Munitions Expended at BT-11
------------------------------------------------------------------------
                                                          Proposed total
                 Proposed munitions \1\                      number of
                                                            rounds \2\
------------------------------------------------------------------------
Small Arms Rounds Excluding .50 Cal.....................         507,812
.50 Cal.................................................         326,234
Large Arms Rounds.......................................         240,334
Rockets.................................................           4,549
Bombs and Grenades......................................          22,114
Pyrotechnics............................................           8,912
                                                         ---------------
    Total...............................................       1,109,955
------------------------------------------------------------------------
\1\ Munitions may be expended from aircraft or small boats.
\2\ Munitions estimated using FY 2007 CURRS data on a per sortie-
  operation basis.

Description of Marine Mammals in the Area of the Specified Activity

    Forty marine mammal species occur within the nearshore and offshore 
waters of North Carolina; however, the majority of these species are 
solely oceanic in distribution. Only one marine mammal species, the 
bottlenose dolphin, has been repeatedly sighted in Pamlico Sound, while 
an additional species, the endangered West Indian manatee (Trichechus 
manatus), has been sighted rarely (Lefebvre et al., 2001; DoN 2003). 
The U.S. Fish and Wildlife Service oversees management of the manatee; 
therefore, authorization to harass manatees would not be included in 
any NMFS' authorization and will not be discussed further.
    No sightings of the endangered North Atlantic right whale 
(Eubalaena glacialis) or other large whales have been observed within 
Pamlico Sound or in vicinity of the BTs (Kenney 2006). No suitable 
habitat exists for these species in the shallow Pamlico Sound or BT 
vicinity; therefore, whales would not be affected by the specified 
activities and will not be discussed further. Other dolphins, such as 
Atlantic spotted (Stenella frontalis) and common dolphins (Delphinus 
delphis), are oceanic in distribution and do not venture into the 
shallow, brackish waters of southern Pamlico Sound. Therefore, the 
specified activity has the potential to affect one marine mammal 
species under NMFS' jurisdiction: the bottlenose dolphin.
    Coastal (or nearshore) and offshore stocks of bottlenose dolphins 
in the Western North Atlantic can be distinguished by genetics, diet, 
blood characteristics, and outward appearance (Duffield et al., 1983; 
Hersh and Duffield, 1990; Mead and Potter, 1995; Curry and Smith, 
1997). Initially, a single stock of coastal morphotype bottlenose 
dolphins was thought to migrate seasonally between New Jersey (summer 
months) and central Florida based on seasonal patterns in strandings 
during a large scale mortality event occurring during 1987-1988 (Scott 
et al., 1988). However, re-analysis of stranding data (McLellan et al., 
2003) and extensive analysis of genetic, photo-identification, 
satellite telemetry, and stable isotope studies demonstrate a complex 
mosaic of coastal bottlenose dolphin stocks (NMFS 2001) which may be 
migratory or resident (they do not migrate and occur within an area 
year round). Four out of the seven designated coastal stocks may occur 
in North Carolina waters at some part of the year: The Northern 
Migratory stock (NM; winter); the Southern Migratory stock (SM; 
winter); the Northern North Carolina Estuarine stock (NNCE; resident, 
year round); and the more recently identified Southern North Carolina 
Estuarine stock (SNCE; resident, year round). Stable isotope depleted 
oxygen signature (hypoxic conditions routinely develops during summer 
in North Carolina waters) (Cortese, 2000), satellite telemetry, and 
photo-identification (NMFS, 2001) support stock structure analysis. 
Dolphins encountered at the BTs likely belong to the NNCE and SNCE 
stock; however, this may not always be the case. NMFS' 2010 stock 
assessment report provides further detail on stock delineation. All 
stocks discussed here are considered depleted (and thus strategic) 
under the MMPA (Waring et al., 2010).
    NMFS provides abundance estimates for the four aforementioned 
migratory and resident coastal stocks in its 2010 stock assessment 
report. The best available abundance estimate for the NNCE stock is the 
combined abundance from estuarine (Read et al., 2003) and coastal 
(aerial survey data dating from 2002) waters. This combined estimate is 
1,387 (Waring et al., 2010). Similarly, the best available abundance 
estimate for the SNCE stock is the combined abundance from estuarine 
and coastal waters. This combined estimate is 2,595 (Waring et al., 
2010). The best abundance estimate for the NM stock, resulting from 
2002 aerial surveys, is 9,604 (Waring et al., 2010). Using the same 
information, the resulting best abundance estimate for the SM stock is 
12,482 (Waring et al., 2010).
    From July 2004 through April 2006, the NMFS' SEFSC conducted 41 
aerial surveys to document the seasonal distribution and estimated 
density of sea turtles and dolphins within Core Sound and portions of 
Pamlico Sound, and coastal waters extending one mile offshore (Goodman 
et al., 2007). Pamlico Sound was divided into two survey areas: western 
(encompassing BT-9 and BT-11) and eastern (including Core Sound and the 
eastern portion of restricted air space R-5306). In total, 281 dolphins 
were sighted in the western range. To account for animals likely missed 
during sightings (i.e., those below the surface), Goodman et al. (2007) 
estimate that, in reality, 415

[[Page 71541]]

dolphins were present. Densities for bottlenose dolphins in the western 
part of Pamlico Sound were calculated to be 0.0272/km\2\ in winter; 
0.2158/km\2\ in autumn; 0.0371/km\2\ in summer; and 0.0946/km\2\ in 
summer (Goodman et al., 2007). Dolphins were sighted throughout the 
entire range when mean sea surface temperature (SST) was 7.60 [deg]C to 
30.82 [deg]C, with fewer dolphins sighted as water temperatures 
increased. Like in Mayer (2003), dolphins were found in higher numbers 
around BT-11, a range where no live firing occurs.
    In 2000, Duke University Marine Lab (DUML), conducted a boat-based 
mark-recapture survey throughout the estuaries, bays and sounds of 
North Carolina (Read et al., 2003). This summer survey yielded a 
dolphin density of 0.183/km\2\ (0.071 mi\2\) based on an estimate of 
919 dolphins for the northern inshore waters divided by an estimated 
5,015 km\2\ (1,936 mi\2\) survey area. Additionally, from July 2002-
June 2003, the USMC supported DUML to conduct dolphin surveys 
specifically in and around BT-9 and BT-11. During these surveys, one 
sighting in the restricted area surrounding BT-9 and two sightings in 
proximity to BT-11 were observed, as well as seven sightings in waters 
adjacent to the BTs. In total, 276 bottlenose dolphins were sighted 
ranging in group size from two to 70 animals with mean dolphin density 
in BT-11 more than twice as large as the density of any of the other 
areas; however, the daily densities were not significantly different 
(Maher, 2003). Estimated dolphin density at BT-9 and BT-11 based on 
these surveys were calculated to be 0.11 dolphins/km\2\, and 1.23 
dolphins/km\2\, respectively, based on boat surveys conducted from July 
2002 through June 2003 (excluding April, May, Sept. and Jan.). However, 
the USMC choose to estimate take of dolphins based on the higher 
density reported from the summer 2000 surveys (0.183/km\2\). Although 
the aerial surveys were conducted year round and therefore provide for 
seasonal density estimates, the average year-round density from the 
aerial surveys is 0.0936, lower than the 0.183/km\2\ density chosen to 
calculate take for purposes of this MMPA authorization. Additionally, 
Goodman et al. (2007) acknowledged that boat based density estimates 
may be more accurate than the uncorrected estimates derived from the 
aerial surveys.
    In Pamlico Sound, bottlenose dolphins concentrate in shallow water 
habitats along shorelines, and few, if any, individuals are present in 
the central portions of the sounds (Gannon, 2003; Read et al., 2003a, 
2003b). The dolphins utilize shallow habitats, such as tributary creeks 
and the edges of the Neuse River, where the bottom depth is less than 
3.5 m (Gannon, 2003). Fine-scale distribution of dolphins seems to 
relate to the presence of topography or vertical structure, such as the 
steeply-sloping bottom near the shore and oyster reefs, which may be 
used to facilitate prey capture (Gannon, 2003). Results of a passive 
acoustic monitoring effort conducted from 2006-2007 by Duke University 
researchers validated this information. Vocalizations of dolphins in 
the BT-11 vicinity were higher in August and September than 
vocalization detection at BT-9, an open water area (Read et al., 2007). 
Additionally, detected vocalizations of dolphins were more frequent at 
night for the BT-9 area and during early morning hours at BT-11.
    Unlike migrating whales which display strong temporal foraging and 
mating/birthing periods, many bottlenose dolphins in Pamlico Sound are 
residents and mate year round. However, dolphins in the southeast U.S. 
do display some reproductive seasonality. Based on neonate stranding 
records, sighting data, and births by known females, the populations of 
dolphins that frequent the North Carolina estuarine waters have calving 
peaks in spring but calving continues throughout the summer and is 
followed by a smaller number of fall births (Thayer et al., 2003).
    Bottlenose dolphins can typically hear within a broad frequency 
range of 0.04 to 160 kHz (Au, 1993; Turl, 1993). Electrophysiological 
experiments suggest that the bottlenose dolphin brain has a dual 
analysis system: one specialized for ultrasonic clicks and another for 
lower-frequency sounds, such as whistles (Ridgway, 2000). Scientists 
have reported a range of highest sensitivity between 25 and 70 kHz, 
with peaks in sensitivity at 25 and 50 kHz (Nachtigall et al., 2000). 
Recent research on the same individuals indicates that auditory 
thresholds obtained by electrophysiological methods correlate well with 
those obtained in behavior studies, except at some lower (10 kHz) and 
higher (80 and 100 kHz) frequencies (Finneran and Houser, 2006).
    Sounds emitted by bottlenose dolphins have been classified into two 
broad categories: pulsed sounds (including clicks and burst-pulses) and 
narrow-band continuous sounds (whistles), which usually are frequency 
modulated. Clicks have a dominant frequency range of 110 to 130 
kiloHertz (kHz) and a source level of 218 to 228 dB re 1 [mu]Pa (peak-
to-peak) (Au, 1993) and 3.4 to 14.5 kHz at 125 to 173 dB re 1 [mu]Pa 
(peak-to-peak) (Ketten, 1998). Whistles are primarily associated with 
communication and can serve to identify specific individuals (i.e., 
signature whistles) (Caldwell and Caldwell, 1965; Janik et al., 2006). 
Up to 52 percent of whistles produced by bottlenose dolphin groups with 
mother-calf pairs can be classified as signature whistles (Cook et al., 
2004). Sound production is also influenced by group type (single or 
multiple individuals), habitat, and behavior (Nowacek, 2005). Bray 
calls (low-frequency vocalizations; majority of energy below 4 kHz), 
for example, are used when capturing fish, specifically sea trout 
(Salmo trutta) and Atlantic salmon (Salmo salar), in some regions 
(i.e., Moray Firth, Scotland) (Janik, 2000). Additionally, whistle 
production has been observed to increase while feeding (Acevedo-
Guti[eacute]rrez and Stienessen, 2004; Cook et al., 2004).

Potential Effects on Marine Mammals

    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].
    The USMC has concluded that harassment to marine mammals may occur 
incidental to munitions firing noise and pressure at the BTs. These 
military readiness activities would result in increased noise levels, 
explosions, and munition debris within bottlenose dolphin habitat. NMFS 
also considered the potential for harassment from vessel and aircraft 
operation. NMFS' analysis of potential impacts from these factors, 
including consideration of the USMC's analysis in its application, is 
outlined below.

Anthropogenic Sound

    Marine mammals respond to various types of anthropogenic sounds 
introduced in the ocean environment. Responses are highly variable and 
depend on a suite of internal and external factors which in turn 
results in varying degrees of significance (NRC, 2003; Southall et al., 
2007). Internal factors include: (1) Individual hearing

[[Page 71542]]

sensitivity, activity pattern, and motivational and behavioral state 
(e.g., feeding, traveling) at the time it receives the stimulus; (2) 
past exposure of the animal to the noise, which may lead to habituation 
or sensitization; (3) individual noise tolerance; and (4) demographic 
factors such as age, sex, and presence of dependent offspring. External 
factors include: (1) Non-acoustic characteristics of the sound source 
(e.g., if it is moving or stationary); (2) environmental variables 
(e.g., substrate) which influence sound transmission; and (3) habitat 
characteristics and location (e.g., open ocean vs. confined area). To 
determine whether an animal perceives the sound, the received level, 
frequency, and duration of the sound are compared to ambient noise 
levels and the species' hearing sensitivity range. That is, if the 
frequency of an introduced sound is outside of the species' frequency 
hearing range, it cannot be heard. Similarly, if the frequency is on 
the upper or lower end of the species hearing range, the sound must be 
louder in order to be heard.
    Marine mammal responses to anthropogenic noise are typically subtle 
and can include visible and acoustic reactions such as avoidance, 
altered dive patterns and cessation of pre-exposure activities and 
vocalization reactions such as increasing or decreasing call rates or 
shifting call frequency. Responses can also be unobservable, such as 
stress hormone production and auditory trauma or fatigue. It is not 
always known how these behavioral and physiological responses relate to 
significant effects (e.g., long-term effects or individual/population 
consequences); however, individuals and populations can be monitored to 
provide some insight into the consequences of exposing marine mammals 
to noise. For example, Haviland-Howell et al. (2007) compared sighting 
rates of bottlenose dolphins within the Wilmington, NC stretch of the 
Atlantic Intracoastal Waterway (ICW) on weekends, when recreational 
vessel traffic was high, to weekdays, when vessel traffic was 
relatively minimal. The authors found that dolphins were less often 
sighted in the ICW during times of increased boat traffic (i.e., on 
weekends) and theorized that because vessel noise falls within the 
frequencies of dolphin communication whistles and primary energy of 
most fish vocalizations, the continuous vessel traffic along that 
stretch of the ICW could result in social and foraging impacts. 
However, the extent to which these impacts affect individual health and 
population structure is unknown.
    A full assessment of marine mammal responses and disturbances when 
exposed to anthropogenic sound can be found in NMFS' proposed 
rulemaking for the Navy Cherry Point Range Complex (74 FR 11057, March 
16, 2009). That rulemaking was made final on June 15, 2009 (74 FR 
28370). In summary, sound exposure may result in physiological impacts, 
stress responses, and behavioral responses which could affect proximate 
or ultimate life functions. Proximate life history functions are the 
functions that the animal is engaged in at the time of acoustic 
exposure. The ultimate life functions are those that enable an animal 
to contribute to the population (or stock, or species, etc.).

I. Physiology-Hearing Threshold Shift

    In mammals, high-intensity sound may rupture the eardrum, damage 
the small bones in the middle ear, or over stimulate the 
electromechanical hair cells that convert the fluid motions caused by 
sound into neural impulses that are sent to the brain. Lower level 
exposures may cause a loss of hearing sensitivity, termed a threshold 
shift (TS) (Miller, 1974). Incidence of TS may be either permanent, 
referred to as permanent threshold shift (PTS), or temporary, referred 
to as temporary threshold shift (TTS). The amplitude, duration, 
frequency, and temporal pattern, and energy distribution of sound 
exposure all affect the amount of associated TS and the frequency range 
in which it occurs. As amplitude and duration of sound exposure 
increase, generally, so does the amount of TS and recovery time. Human 
non-impulsive noise exposure guidelines are based on exposures of equal 
energy (the same SEL) producing equal amounts of hearing impairment 
regardless of how the sound energy is distributed in time (NIOSH 1998). 
Until recently, previous marine mammal TTS studies have also generally 
supported this equal energy relationship (Southall et al., 2007). Three 
newer studies, two by Mooney et al. (2009a, 2009b) on a single 
bottlenose dolphin either exposed to playbacks of Navy MFAS or octave-
band noise (4-8 kHz) and one by Kastak et al. (2007) on a single 
California sea lion exposed to airborne octave-band noise (centered at 
2.5 kHz), concluded that for all noise exposure situations the equal 
energy relationship may not be the best indicator to predict TTS onset 
levels. Generally, with sound exposures of equal energy, those that 
were quieter (lower sound pressure level [SPL]) with longer duration 
were found to induce TTS onset more than those of louder (higher SPL) 
and shorter duration (more similar to noise from AS Cherry Point 
exercises). For intermittent sounds, less TS will occur than from a 
continuous exposure with the same energy (some recovery will occur 
between exposures) (Kryter et al., 1966; Ward, 1997). Additionally, 
though TTS is temporary, very prolonged exposure to sound strong enough 
to elicit TTS, or shorter-term exposure to sound levels well above the 
TTS threshold, can cause PTS, at least in terrestrial mammals (Kryter, 
1985). However, these studies highlight the inherent complexity of 
predicting TTS onset in marine mammals, as well as the importance of 
considering exposure duration when assessing potential impacts.
    PTS consists of non-recoverable physical damage to the sound 
receptors in the ear, which can include total or partial deafness, or 
an impaired ability to hear sounds in specific frequency ranges; PTS is 
considered Level A harassment. TTS is recoverable and is considered to 
result from temporary, non-injurious impacts to hearing-related 
tissues; TTS is considered Level B harassment.

Permanent Threshold Shift

    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 irreversible and considered to be an injury that 
could result in PTS. 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. In some cases, there can be total or partial deafness 
across all frequencies, whereas in other cases, the animal has an 
impaired ability to hear sounds in specific frequency ranges. There is 
no empirical data for onset of PTS in any marine mammal, and therefore, 
PTS- onset must be estimated from TTS-onset measurements and from the 
rate of TTS growth with increasing exposure levels above the level 
eliciting TTS-onset. PTS is presumed to be likely if the hearing 
threshold is reduced by >= 40 dB (i.e., 40 dB of TTS). Relationships 
between TTS and PTS thresholds have not been studied in marine mammals, 
but are assumed to be similar to those in humans and other terrestrial 
mammals.

[[Page 71543]]

Temporary Threshold Shift

    TTS is the mildest form of hearing impairment that can occur during 
exposure to a loud sound (Kryter, 1985). 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 as Level 
B Harassment, not Level A Harassment (injury); however, NMFS does not 
consider the onset of TTS to be the lowest level at which Level B 
Harassment may occur (see III. Behavior section below).
    Southall et al. (2007) considers a 6 dB TTS (i.e., baseline hearing 
thresholds are elevated by 6 dB) sufficient to be recognized as an 
unequivocal deviation and thus a sufficient definition of TTS onset. 
TTS in bottlenose dolphin hearing have been experimentally induced. For 
example, Finneran et al. (2002) exposed a trained captive bottlenose 
dolphin to a seismic watergun simulator with a single acoustic pulse. 
No TTS was observed in the dolphin at the highest exposure condition 
(peak: 207 kPa [30psi]; peak-to-peak: 228 dB re: 1 microPa; SEL: 188 dB 
re 1 microPa\2\-s). Schludt et al. (2000) demonstrated temporary shifts 
in masked hearing thresholds in five bottlenose dolphins occurring 
generally between 192 and 201 dB rms (192 and 201 dB SEL) after 
exposure to intense, non-pulse, 1-s tones at, 3kHz, 10kHz, and 20 kHz. 
TTS onset occurred at mean sound exposure level of 195 dB rms (195 dB 
SEL). At 0.4 kHz, no subjects exhibited threshold shifts after SPL 
exposures of 193dB re: 1 microPa (192 dB re: 1 microPa\2\-s). In the 
same study, at 75 kHz, one dolphin exhibited a TTS after exposure at 
182 dB SPL re: 1 microPa but not at higher exposure levels. Another 
dolphin experienced no threshold shift after exposure to maximum SPL 
levels of 193 dB re: 1 microPa at the same frequency. Frequencies of 
explosives used at MCAS Cherry Point range from 1-25 kHz; the range 
where dolphin TTS onset occurred at 195 dB rms in the Schludt et al. 
(2000) study.
    Preliminary research indicates that TTS and recovery after noise 
exposure are frequency dependent and that an inverse relationship 
exists between exposure time and sound pressure level associated with 
exposure (Mooney et al., 2005; Mooney, 2006). For example, Nachtigall 
et al. (2003) measured TTS in a bottlenose dolphin and found an average 
11 dB shift following a 30 minute net exposure to OBN at a 7.5 kHz 
center frequency (max SPL of 179 dB re: 1 microPa; SEL: 212-214 dB re: 
1 microPa\2\-s). No TTS was observed after exposure to the same 
duration and frequency noise with maximum SPLs of 165 and 171 dB re: 1 
microPa. After 50 minutes of exposure to the same 7.5 kHz frequency 
OBN, Natchigall et al. (2004) measured a 4-8 dB shift (max SPL: 160dB 
re 1microPa; SEL: 193-195 dB re:1 microPa\2\-s). Finneran et al. (2005) 
concluded that a sound exposure level of 195 dB re 1 [mu]Pa2-s is a 
reasonable threshold for the onset of TTS in bottlenose dolphins 
exposed to mid-frequency tones.

II. Stress Response

    An 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. Here, 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 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. 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. Any immediate effect of exposure that 
produces an injury is assumed to also produce a stress response and 
contribute to the 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). 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.

III. Behavior

    Changes in marine mammal behavior in response to anthropogenic 
noise may include altered travel directions, increased swimming speeds, 
changes in dive, surfacing, respiration and feeding patterns, and 
changes in vocalizations. As described above, lower level physiological 
stress responses could also co-occur with altered behavior; however, 
stress responses are more difficult to detect and fewer data exist 
relative to specific received levels of sound.

Acoustic Masking

    Anthropogenic noise can interfere with, or mask, detection of 
acoustic signals such as communication calls, echolocation, and 
environmental sounds important to marine mammals. Southall et al. 
(2007) defines auditory masking as the partial or complete reduction in 
the audibility of signals due to the presence of interfering noise with 
the degree of masking depending on the spectral, temporal, and spatial 
relationships between signals and masking noise, as well as the 
respective received levels. Masking of sender communication space can 
be considered as the amount of change in a sender's communication space 
caused by the presence of other sounds, relative to a pre-industrial 
ambient noise condition (Clark et al., in press). 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. Projecting noise into

[[Page 71544]]

the marine environment which causes 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. To compensate for masking, 
marine mammals, including bottlenose dolphins, are known to increase 
their levels of vocalization as a function of background noise by 
increasing call repetition and amplitude, shifting calls higher 
frequencies, and/or changing the structure of call content (Lesage et 
al., 1999; Scheifele et al., 2005; McIwem, 2006).
    While it may occur temporarily, NMFS does not expect auditory 
masking to result in detrimental impacts to an individual's or 
population's survival, fitness, or reproductive success. Dolphins are 
not confined to the BT ranges; allowing for movement out of area to 
avoid masking impacts. The USMC would also conduct visual sweeps of the 
area before any training exercise and implement training delay 
mitigation measures if a dolphin is sighted within designated zones 
(see Proposed Mitigation Measures section below). As discussed 
previously, the USMC has been working with DUML to collect baseline 
information on dolphins in Pamlico Sound, specifically dolphin 
abundance and habitat use around the BTs. The USMC has also recently 
accepted a DUML proposal to investigate methods of dolphin acoustic 
detection around the BTs. NMFS would encourage the USMC to expand 
acoustic investigations to include the impacts of training exercises on 
vocalization properties (e.g., call content, duration, frequency) and 
masking (e.g., communication and foraging impairment) of the affected 
population of dolphins in Pamlico Sound.

Assessment of Marine Mammal Impacts From Explosive Ordnances

    MCAS Cherry Point plans to use five types of explosive sources 
during its training exercises: 2.75'' Rocket High Explosives, 5'' 
Rocket High Explosives, 30 mm High Explosives, 40 mm High Explosives, 
and G911 grenades. The underwater explosions from these weapons 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. In general, potential impacts from 
explosive detonations can range from brief effects (such as short term 
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).
    Explosives produce significant acoustic energy across several 
frequency decades of bandwidth (i.e., broadband). Propagation loss is 
sufficiently sensitive to frequency as to require model estimates at 
several frequencies over such a wide band. The effects of an underwater 
explosion on a marine mammal depend 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. The net explosive weight (or NEW) of an explosive is the 
weight of TNT required to produce an equivalent explosive power. The 
detonation depth of an explosive is particularly important due to a 
propagation effec