Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental To Conducting Air-to-Surface Gunnery Missions in the Gulf of Mexico, 43267-43277 [2011-18324]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 139 (Wednesday, July 20, 2011)]
[Notices]
[Pages 43267-43277]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-18324]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA471


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental To Conducting Air-to-Surface Gunnery 
Missions in the Gulf of Mexico

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

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

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SUMMARY: NMFS received an application from the U.S. Air Force (USAF), 
Eglin Air Force Base (Eglin AFB), for renewal of an Incidental 
Harassment Authorization (IHA) to take marine mammals, by harassment, 
incidental to conducting air-to-surface (A-S) gunnery missions in the 
Gulf of Mexico (GOM). The USAF's activities are considered military 
readiness activities. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS requests comments on its proposal to issue an IHA to Eglin 
AFB to take, by harassment, several species of marine mammal during the 
specified activity for a period of 1 year.

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

ADDRESSES: Comments on the application 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. The mailbox address for providing e-
mail comments is ITP.Hopper@noaa.gov. NMFS is not responsible for e-
mail comments sent to addresses other than the one provided here. 
Comments sent via e-mail, including all attachments, must not exceed a 
10-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally 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 document and NMFS' 2008 Environmental Assessment (EA) and 
Finding of No Significant Impact (FONSI) 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. Documents cited in this 
notice may also be viewed, by appointment, during regular business 
hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Brian D. Hopper or Candace Nachman, 
Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) 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 small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings 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 (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
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 U.S. 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 National Defense Authorization Act (NDAA) (Pub. L. 108-136) 
removed the ``small numbers'' and ``specified geographical region'' 
provisions 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

    NMFS originally received an application on February 13, 2003, from 
Eglin AFB for the taking, by harassment, of marine mammals incidental 
to programmatic mission activities within the Eglin Gulf Test and 
Training Range (EGTTR). The EGTTR is described as the airspace over the 
GOM that is controlled by Eglin AFB. A notice of receipt of Eglin AFB's 
application and Notice of Proposed IHA and request for 30-day public 
comment published on January 23, 2006 (71 FR 3474). A 1-year IHA was 
subsequently issued to Eglin AFB for

[[Page 43268]]

this activity on May 3, 2006 (71 FR 27695, May 12, 2006).
    On January 29, 2007, NMFS received a request from Eglin AFB for a 
renewal of its 2006-2007 IHA, which expired on May 2, 2007. This 
application addendum requested revisions to three components of the IHA 
requirements: Protected species surveys; ramp-up procedures; and sea 
state restrictions. A Notice of Proposed IHA and request for 30-day 
public comment published on May 30, 2007 (72 FR 29974). A 1-year IHA 
was subsequently issued to Eglin AFB for this activity on December 11, 
2008 (73 FR 78318, December 22, 2008) and was effective through 
December 10, 2009.
    On February 17, 2009, NMFS received a request from Eglin AFB for a 
renewal of its 2008-2009 IHA, which was valid through December 10, 
2009. No modifications to the activity location, the mission 
activities, or the mitigation and monitoring measures that were 
required under the 2008-2009 IHA were requested by Eglin AFB at that 
time. A Notice of Proposed IHA and request for 30-day public comment 
published on October 19, 2009 (74 FR 53474). A 1-year IHA was 
subsequently issued to Eglin AFB for this activity on January 27, 2010 
(75 FR 5045, February 1, 2010), which expired on January 26, 2011.
    On May 16, 2011, NMFS received a request from Eglin AFB for a 
renewal of its IHA, which expired on January 26, 2011. This application 
is the one considered by NMFS for this request. Eglin AFB has not had 
coverage for these activities since expiration of the third IHA. 
However, Eglin AFB has not conducted these activities during the period 
without MMPA coverage and will wait to resume these training missions 
until a new MMPA authorization is issued by NMFS.
    A-S gunnery operations may potentially impact marine mammals at or 
near the water surface. Marine mammals could potentially be harassed, 
injured, or killed by exploding and non-exploding projectiles, and 
falling debris (USAF, 2002). However, based on analyses provided in the 
USAF's 2002 Final Programmatic EA (PEA), Eglin's Supplemental 
Information Request (2003), and NMFS' 2008 EA, as well as for reasons 
discussed later in this document, NMFS concurs with Eglin that gunnery 
exercises are not likely to result in any injury or mortality to marine 
mammals. Potential impacts resulting from A-S test operations include 
direct physical impacts (DPI) resulting from ordnance. Eglin AFB has 
requested to take six cetacean species by Level B harassment. The 
requested species include: dwarf sperm whale (Kogia simus); pygmy sperm 
whale (K. breviceps); Atlantic bottlenose dolphin (Tursiops truncatus); 
Atlantic spotted dolphin (Stenella frontalis); pantropical spotted 
dolphin (S. attenuata); and spinner dolphin (S. longirostris). In 
addition, although Eglin AFB's acoustic model predicted the take of two 
cetacean species by Level A harassment (two Atlantic bottlenose dolphin 
and one Atlantic spotted dolphin), neither NMFS nor Eglin AFB 
anticipate that injurious Level A harassment will result from the 
proposed A-S gunnery missions because of Eglin AFB's standard 
mitigation measures; therefore, NMFS is not proposing to authorize 
Level A takes of marine mammals.

Description of the Specified Activity

    A-S gunnery missions, a ``military readiness activity'' as defined 
under 16 U.S.C. 703 note, involve surface impacts of projectiles and 
small underwater detonations with the potential to affect cetaceans 
that may occur within the EGTTR. These missions typically involve the 
use of 25-mm (0.98-in), 40-mm (1.57-in), and 105-mm (4.13-in) gunnery 
rounds containing, 0.0662 lb (30 g), 0.865 lb (392 g), and 4.7 lbs (2.1 
kg) of explosive, respectively. Live rounds must be used to produce a 
visible surface splash that must be used to ``score'' the round (the 
impact of inert rounds on the sea surface would not be detected). The 
USAF has developed a 105-mm training round (TR) that contains less than 
10 percent of the amount of explosive material (0.35 lb; 0.16 kg) as 
compared to the ``Full-Up'' (FU) 105-mm (4.13 in) round. The TR was 
developed as one method to mitigate effects on marine life during 
nighttime A-S gunnery exercises when visibility at the water surface is 
poor. However, the TR cannot be used in the daytime since the amount of 
explosive material is insufficient to be detected from the aircraft.
    Water ranges within the EGTTR that are typically used for the 
gunnery operations are located in the GOM offshore from the Florida 
Panhandle (areas W-151A, W-151B, W-151C, and W-151D as shown in Figure 
1-2 in Eglin's 2011 application). Data indicate that W-151A (Figure 1-3 
in Eglin's application) is the most frequently used water range due to 
its proximity to Hurlburt Field, but activities may occur anywhere 
within the EGTTR.
    Eglin AFB proposes to conduct these mission activities year round 
during both daytime and nighttime hours. Therefore, NMFS proposes to 
make the IHA effective for an entire year from the date of issuance (if 
the IHA is issued).
    As required under the 2006 IHA, the AC-130 gunship aircraft was to 
conduct at least two complete orbits at a minimum safe airspeed around 
a prospective target area at a maximum altitude of 1,500 ft (457 m). 
Based on an amendment requested by Eglin AFB, NMFS required an 
operational altitude of approximately 4,500 to 10,000 ft (1,372-3,048 
m) in the 2008 IHA. Ascent occurs over a 10-15 minute period. Eglin AFB 
has noted that the search area for these orbits ensures that no vessels 
(or protected species) are within an area of 5 nm (9.3 km) of the 
target. The AC-130 continues orbiting the selected target point as it 
climbs to the mission-testing altitude. During the low altitude orbits 
and the climb to testing altitude, aircraft crew visually scan the sea 
surface within the aircraft's orbit circle for the presence of vessels 
and protected species. Primary responsibility for the surface scan is 
on the flight crew in the cockpit and personnel stationed in the tail 
observer bubble and starboard viewing window. The AC-130's optical and 
electronic sensors are also employed for target clearance. If any 
marine mammals are detected within the AC-130's orbit circle, either 
during initial clearance or after commencement of live firing, the 
aircraft will relocate to another target area and repeat the clearance 
procedures. A typical distance from the coast for this activity is at 
least 15 mi (24 km).
    When offshore, the crews can scan a 5-nm (9.3-km) radius around the 
potential impact area to ensure it is clear of surface craft, marine 
mammals, and sea turtles. Scanning is accomplished using radar, all-
light television (TV), infrared sensors (IR), and visual means. An 
alternative area would be selected if any cetaceans or vessels were 
detected within a 5-nm (9.3 km) search area. Once the scan is 
completed, Mk-25 flares are dropped and the firing sequence is 
initiated.
    A typical gunship mission lasts approximately 5 hrs without 
refueling and 6 hrs when air-to-air refueling is accomplished. A 
typical mission includes the following sequence of events: (1) 30 min 
for take-off and to perform airborne sensor alignment, align electro-
optical sensors (IR and TV) to heads-up display; (2) 1.5 to 2 hrs of 
dry fire (no ordnance expended) and includes transition time; (3) 1.5 
to 2 hrs of live fire, and includes clearing the area and transiting to 
and from the range (actual firing activities typically do not exceed 30 
min); (4) 1 hr air-to-air refueling, if and when performed; and (5) 30 
min of transition work (take-offs, approaches, and landings-pattern 
work).

[[Page 43269]]

    The guns are fired during the live-fire phase of the mission. The 
actual firing can last from 30 min to 1.5 hrs but is typically 
completed in 30 min. The number and type of A-S gunnery munitions 
deployed during a mission varies with each type of mission flown. In 
addition to the 25-, 40-, and 105-mm rounds, marking flares are also 
deployed as targets. All guns are fired at a specific target in the 
water, usually the Mk-25 flares, starting with the lowest caliber 
ordnance or action with the least impact and proceeding to greater 
caliber sizes. To establish the test target area, two Mk-25 flares are 
deployed into the center of the 5-nm (9.3-km) radius cleared area 
(visually clear of aircraft, ships, and surface marine species) on the 
water's surface. The flare's burn time normally lasts 10 to 20 min but 
could be much less if actually hit with one of the ordnance 
projectiles; however, some flares have burned as long as 40 min. Live 
fires are a continuous event with pauses during the firing usually well 
under a minute and rarely from 2 to 5 min. Firing pauses would only 
exceed 10 min if surface boat traffic or marine protected species 
caused the mission to relocate; if aircraft, gun, or targeting system 
problems existed; or if more flares needed to be deployed. The Eglin 
Safety Office has described the gunnery missions as having 95-percent 
containment with a 99-percent confidence level within a 5-m (16.4-ft) 
area around the established flare target test area.

Live-fire Event: 25-mm Round

    The 25-mm (0.98-in) firing event in a typical mission includes 
approximately 560 rounds. These rounds are fired in short bursts of 100 
rounds. These bursts last approximately 2-3 s with approximately 100 
rounds per burst. Based on the very tight target area and extremely 
small ``miss'' distance, these bursts of rounds all enter the water 
within a 5-m (16.4-ft) area. Therefore, when calculations of the marine 
mammal Zone of Influence (ZOI) and take estimates are made later in 
this document for the 25-mm rounds, calculations will be based on the 
total number of rounds fired per year divided by 100.

Live-fire Event: 40-mm Round

    The 40-mm (1.57 in) firing event in a typical mission includes 
approximately 64 rounds with approximately 20 rounds per burst. Each 
burst lasts from about 2 to 10 seconds. Based on the very tight target 
area and extremely small ``miss'' distance, these bursts of rounds all 
enter the water within a 5-m (16.4 ft) area. Therefore, when 
calculations of the marine mammal ZOI and take estimates are made later 
in this document for the 40-mm rounds, calculations will be based on 
the total number of rounds fired per year divided by 20.

Live-fire Event: 105-mm Round

    The 105-mm firing event in a typical mission includes approximately 
30 rounds. These rounds are not fired in bursts but as single shots. 
The 105-mm firing event lasts approximately 5 min with approximately 
two rounds per minute. Due to the single firing event of the 105-mm 
round, the peak pressure of each single 105-mm round is measured at a 
given distance (91 m (295 ft) for the 105-mm TR and 216 m (709 ft) for 
the 105-mm FU).
    As described in Eglin's 2011 application, gunnery testing in this 
request includes historical baseline yearly amounts in addition to 
proposed nighttime gunnery missions. Daytime gunnery testing uses the 
105-mm FU round and nighttime gunnery training is proposed using the 
105-mm TR. The number of 105-mm rounds including nighttime operations 
would amount to 2,100. As shown in detail in Table 1, Eglin proposes to 
conduct a total of 25 daytime missions and 45 nighttime missions 
annually, expending 16,350 rounds in the daytime and 29,430 rounds at 
night (750 105-mm FU and 1,350 rounds would be the 105-mm TR).

            Table 1--Annual Summary of Daytime and Nighttime Gunnery Testing Operations in the EGTTR
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                                                                            Number of    Rounds per
                 Category                             Expendable             missions     missions     Quantity
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Daytime Missions..........................  105 mm HE....................           25           30          750
                                            25 mm HEI....................                        64        1,600
                                            40 mm HEI....................                       560       14,000
Nighttime Missions........................  105 mm HE....................           45           30        1,350
                                            25 mm HEI....................                        64        2,880
                                            40 mm HEI....................                       560       25,200
                                           ---------------------------------------------------------------------
    Total.................................  .............................           70  ...........       45,780
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Description of Marine Mammals in the Area of the Specified Activity

    There are 29 species of marine mammals documented as occurring in 
Federal waters of the GOM. Of these 29 species of marine mammals, 
approximately 21 may be found in the vicinity of the proposed action 
area, the EGTTR. These species are the Bryde's whale (Balaenoptera 
edeni), sperm whale (Physeter macrocephalus), dwarf sperm whale (Kogia 
sima), pygmy sperm whale (K. breviceps), Atlantic bottlenose dolphin 
(Tursiops truncatus), Atlantic spotted dolphin (Stenella frontalis), 
pantropical spotted dolphin (S. atenuarta), Blainville's beaked whale 
(Mesoplodon densirostris), Cuvier's beaked whale (Ziphius cavirostris), 
Gervais' beaked whale (M. europaeus), Clymene dolphin (S. clymene), 
spinner dolphin (S. longirostris), striped dolphin (S. coeruleoalba), 
killer whale (Orcinus orca), false killer whale (Pseudorca crassidens), 
pygmy killer whale (Feresa attenuata), Risso's dolphin (Grampus 
griseus), Fraser's dolphin (Lagenodelphis hosei), melon-headed whale 
(Peponocephala electra), rough-toothed dolphin (Steno bredanensis), and 
short-finned pilot whale (Globicephala macrorhynchus). Of these 
species, only the sperm whale is listed as endangered under the 
Endangered Species Act (ESA) and as depleted throughout its range under 
the MMPA. While some of the other species listed here have depleted 
status under the MMPA, none of the GOM stocks of those species are 
considered depleted. Eglin AFB's 2011 MMPA application contains a 
detailed discussion on the description, status, distribution, regional 
distribution, diving behavior, and acoustics and hearing for the marine 
mammals in the EGTTR. Additionally, more detailed information on these 
species can be found in Wursig et al. (2000), NMFS' 2008 EA (see 
ADDRESSES), and in the NMFS U.S. Atlantic and GOM Stock Assessment 
Reports (SARs; Waring et al., 2009). This latter document is available 
at:

[[Page 43270]]

https://www.nefsc.noaa.gov/publications/tm/tm210/. The West Indian 
manatee (Trichechus manatus) is managed by the U.S. Fish and Wildlife 
Service and is not considered further in this proposed IHA Federal 
Register notice.
    The species most likely to occur in the area of Eglin AFB's 
proposed activities for which takes have been requested include: 
Atlantic bottlenose dolphin; Atlantic spotted dolphin; pantropical 
spotted dolphin; spinner dolphin; and dwarf and pygmy sperm whales. 
Bryde's whales, sperm whales, Blainville's beaked whales, Cuvier's 
beaked whales, Gervais' beaked whales, killer whales, false killer 
whales, pygmy killer whales, Risso's dolphins, Fraser's dolphins, 
striped dolphins, Clymene dolphins, rough-toothed dolphins, short-
finned pilot whales, and melon-headed whales are rare in the project 
area and are not anticipated to be impacted by the A-S gunnery mission 
activities. Therefore, these species are not considered further in this 
proposed IHA Federal Register notice.
    For all species other than the bottlenose dolphin, density 
estimates were derived from the Navy OPAREA Density Estimates (NODE) 
for the GOMEX OPAREA report (DON, 2007). Densities were determined 
using one of two methods: (1) Model-derived estimates; or (2) SAR or 
other literature-derived estimates. For the model-based approach, 
density estimates were calculated for each species within areas 
containing survey effort. A relationship between these density 
estimates and associated environmental parameters such as depth, slope, 
distance from the shelf break, sea surface temperature, and 
chlorophyll-a concentration was formulated using generalized additive 
models. This relationship was then used to generate a two-dimensional 
density surface for the region by predicting densities in areas where 
no survey data exist. All analyses for cetaceans in the GOM were based 
on data collected through NMFS-derived vessel surveys conducted between 
1996 and 2004. Species-specific density estimates derived through 
spatial modeling were compared with abundance estimates found in the 
most current SAR to ensure consistency.
    Cetacean density estimates provided by various researchers often do 
not contain adjustments for perception or availability bias. Perception 
bias refers to the failure of observers to detect animals, although 
they are present in the survey area and available to be seen. 
Availability bias refers to animals that are in the survey area, but 
are not able to be seen because they are submerged when observers are 
present. Perception and availability bias result in the underestimation 
of abundance and density numbers (negative bias). The density estimates 
provided in the NODE report are not corrected for negative bias and, 
therefore, likely underestimate density. In order to address potential 
negative bias, density estimates were adjusted using submergence 
factors. Although submergence time versus surface time probably varies 
between and among species populations based on geographic location, 
season, and other factors, submergence times suggested by Moore and 
Clark (1998) were used for this proposed IHA.
    Bottlenose dolphin density estimates were derived from Protected 
Species Habitat Modeling in the EGTTR (Garrison, 2008). NMFS developed 
habitat models using recent aerial survey line transect data collected 
during winter and summer. In combination with remotely sensed habitat 
parameters (sea surface temperature and chlorophyll), these data were 
used to develop spatial density models for cetaceans within the 
continental shelf and coastal waters of the eastern GOM. Encounter 
rates during the aerial surveys were corrected for sighting 
probabilities and the probability that animals were available on the 
surface to be seen. Given that the survey area completely overlaps the 
present study area and that these survey data are the most recent and 
best available, these models are considered to best reflect the 
occurrence of bottlenose dolphins within the study area. Density 
estimates were calculated for a number of subareas within the EGTTR, 
and also aggregated into four principal area categories: (1) North-
Inshore; (2) South-Inshore; (3) North-Offshore; and (4) South-Offshore. 
The proposed action would occur within W-151, which is located in the 
northernmost portion of the EGTTR (Figures 1-2 and 1-3 in Eglin AFB's 
2011 application; see ADDRESSES). Therefore, densities in the northern 
areas are considered to be the most applicable. In order to provide 
conservative impact estimates, the greatest density between summer and 
winter seasons was selected. Densities for northern inshore (shoreline 
to 20 m water depth) and offshore (20 to 200 m water depth) strata were 
averaged, resulting in an overall density estimate of 0.6319 bottlenose 
dolphins per square kilometer (km\2\) to be used in this proposed IHA.
    Cetaceans inhabiting the study area may be grouped as odontocetes 
(toothed whales, including dolphins) or mysticetes (baleen whales), but 
most of the cetaceans occurring in the Gulf are odontocetes. Typically, 
very few baleen whales are found in the Gulf and none are expected to 
occur within the study area given the known distribution of these 
species. Within the bulk of the EGTTR, over the west Florida 
continental shelf, the most common species is the bottlenose dolphin 
(Garrison, 2008), and the Atlantic spotted dolphin also occurs commonly 
over the continental shelf (Fulling et al., 2003). In the continental 
slope waters covered by the EGTTR between the 200 m and 2,000 m 
isobaths, the most common species include bottlenose dolphins, spinner 
dolphins, and pantropical spotted dolphins in the deeper part of this 
area. For conservative analysis, the greatest density between summer 
and winter was used (Table 3-1 in Eglin AFB's 2011 application; see 
ADDRESSES).

Potential Effects of the Specified Activity on Marine Mammals

    A-S gunnery operations may potentially impact marine mammals at or 
near the water surface. Marine mammals could potentially be harassed, 
injured or killed by exploding and non-exploding projectiles, and 
falling debris (USAF, 2002). However, based on analyses provided in the 
USAF's Final PEA, Eglin's Supplemental Information Request (2003), and 
NMFS' 2008 EA, NMFS concurs with Eglin that gunnery exercises are not 
likely to result in any injury or mortality to marine mammals.
    Explosive criteria and thresholds for assessing impacts of 
explosions on marine mammals were discussed by NMFS in detail in its 
issuance of an IHA for Eglin's Precision Strike Weapon testing activity 
(70 FR 48675, August 19, 2005) and are not repeated here. Please refer 
to that document for this background information. However, one part of 
the analysis has changed. That information is provided here.
    Subsequent to the issuance of the USAF 2002 PEA, NMFS updated one 
of the dual criteria related to the onset level for temporary threshold 
shift (TTS; Level B harassment). The USAF 2002 PEA describes the onset 
of TTS by a single explosion (impulse) based on the criterion in use at 
that time. Newly available information based on lab controlled 
experiments that used a seismic watergun to induce TTS in one beluga 
whale and one bottlenose dolphin (Finneran et al., 2002) showed 
measured TTS2 (TTS level 2 min after exposure) was 7 and 6 
dB in the beluga at 0.4 and 30 kHz, respectively, after exposure to 
intense single pulses at 226 dB re: 1 [micro]Pa p-p (peak to peak). 
This sound pressure level (SPL) is equivalent

[[Page 43271]]

to 23 pounds per square inch (psi). Hearing threshold returned to 
within 2 dB of the pre-exposure value within 4 min of exposure. No TTS 
was observed in the bottlenose dolphin at the highest exposure 
condition (228 dB re 1 [micro]Pa p-p). Therefore, NMFS updated the SPL 
from impulse sound that could induce TTS to 23 psi, from the previous 
12 psi. Table 3 in this document outlines the acoustic criteria used by 
NMFS when addressing noise impacts from explosives. These criteria 
remain consistent with criteria established for other activities in the 
EGTTR and other acoustic activities authorized under sections 
101(a)(5)(A) and (D) of the MMPA. The 23 psi criterion is used in this 
document and NMFS' 2008 EA for evaluating the potential for the onset 
of TTS (Level B harassment) in marine mammals. Additional information 
on the derivation of the 23 psi criterion can be found in the Final 
Environmental Impact Statement/Overseas Environmental Impact Statement 
for the Shock Trial of the Mesa Verde (LPD 19) (Department of the Navy, 
2008).

 Table 3--Current NMFS Acoustic Criteria When Addressing Harassment From
                               Explosives
------------------------------------------------------------------------
 
------------------------------------------------------------------------
Level B Behavior..........................  176 dB \1/3\ Octave SEL
                                             (sound energy level).
Level B TTS Dual Criterion................  182 dB \1/3\ Octave SEL.
Level A PTS (permanent threshold shift)...  205 dB SEL.
Level B Dual Criteria.....................  23 psi.
Level A Injury............................  13 psi-msec.
Mortality.................................  30.5 psi-msec.
------------------------------------------------------------------------

Direct Physical Impacts (DPI)

    Potential impacts resulting from A-S test operations include DPI 
resulting from ordnance. DPI could result from gunnery ammunition 
falling into the water. Marine mammals swimming at the surface could 
potentially be injured or killed by projectiles if not sighted and 
firing discontinued; however, the possibility of DPI to marine mammals 
is considered highly unlikely. Therefore, the risk of injury or 
mortality from DPI is discountable. The assumptions made by Eglin AFB 
for DPI calculations can be found in the USAF 2002 Final PEA under the 
analysis for Alternative 1.

Anticipated Effects on Habitat

    The primary source of marine mammal habitat impact is noise 
resulting from gunnery missions. However, the noise does not constitute 
a long-term physical alteration of the water column or bottom 
topography, as the occurrences are of limited duration and are 
intermittent in time. The target flare's burn time normally lasts 10 to 
20 min. Given this short time during which the environment is lighted 
and the variable locations they are dropped, no increases in density of 
phytoplankton or other organisms introducing primary productivity into 
the waters are expected to affect marine mammal habitat or populations. 
Also, live fires are a continuous event with pauses during the firing 
usually well under a minute and rarely from 2 to 5 min. Likewise, 
surface vessels associated with the missions are present in limited 
duration and are intermittent as well.
    Other sources that may affect marine mammal habitat were considered 
and potentially include the introduction of fuel, chaff, debris, 
ordnance, and chemical residues into the water column. Chemical 
residues can enter the water through ammunition, flares, drones, 
missiles, and smoke. However, the small quantities of chemical 
compounds that may potentially be introduced into the marine waters of 
the eastern GOM would rapidly disperse. These additions would be too 
small to adversely impact the GOM waters.
    Based on this information, NMFS has preliminarily determined that 
the proposed A-S gunnery mission activities will not have any impact on 
the food or feeding success of marine mammals in the northern GOM. 
Additionally, no loss or modification of the habitat used by cetaceans 
in the GOM is expected. Marine mammals are anticipated to temporarily 
vacate the area of live fire events. However, these events usually do 
not last more than 90 to 120 min at a time, and animals are anticipated 
to return to the activity area during periods of non-activity. Thus, 
the proposed activity is not expected to have any habitat-related 
effects that could cause significant or long-term consequences for 
individual marine mammals or on the food sources that they utilize.

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) under 
sections 101(a)(5)(A) and (D) of the MMPA, NMFS must, where applicable, 
set forth the permissible methods of taking pursuant to such activity 
and other means of effecting the least practicable impact on such 
species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such species or stock for taking for certain 
subsistence uses (where relevant). The NDAA of 2004 amended the MMPA as 
it relates to military readiness activities and the ITA process such 
that ``least practicable impact'' shall include consideration of 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the ``military readiness activity''. The training 
activities described in Eglin AFB's application are considered military 
readiness activities.
    The mitigation measures proposed for inclusion in the IHA are the 
same as those required in the 2010-2011 IHA (75 FR 5045, February 1, 
2010). These measures are virtually identical to the mitigation 
measures that were required in the 2008 IHA (73 FR 78318, December 22, 
2008) and the 2006 IHA (71 FR 27695, May 12, 2006). There were only 
three differences in the mitigation and monitoring measures between the 
2006 and 2008 IHAs. Eglin AFB's 2007 application addendum requested 
revisions to three components of the IHA requirements: Protected 
species surveys, ramp-up procedures, and sea state restrictions. A 
discussion of the differences in the requirements can be found in the 
2008 IHA Notice of Issuance (73 FR 78318, December 22, 2008) and NMFS' 
2008 EA. The revisions to those three requirements are also included in 
this proposed IHA. However, the explanations as to why Eglin AFB 
requested the changes and NMFS' determinations specific to those three 
requirements are not repeated in this document. Readers should refer to 
either the 2008 IHA notice or NMFS' 2008 EA (see ADDRESSES) for the 
full explanation.

Development of the Training Round

    The largest type of ammunition used during typical gunnery missions 
is the 105-mm (4.13-in) round containing 4.7 lbs (2.1 kg) of high 
explosive (HE). This is several times more HE than that found in the 
next largest round (40 mm/1.57 in). As a mitigation technique, the USAF 
developed a 105-mm TR that contains only 0.35 lb (0.16 kg) of HE. The 
TR was developed to dramatically reduce the risk of harassment at night 
and Eglin AFB anticipates a 96 percent reduction in impact by using the 
105-mm TR.

Visual Mitigation

    Areas to be used in gunnery missions are visually monitored for 
marine mammal presence from the AC-130 aircraft prior to commencement 
of the mission. If the presence of one or more marine mammals is 
detected, the target area will be avoided. In addition, monitoring will 
continue during the mission. If marine mammals are detected at any 
time, the mission will halt immediately and relocate as necessary or be 
suspended until the

[[Page 43272]]

marine mammal has left the area. Daytime and nighttime visual 
monitoring will be supplemented with IR and TV monitoring. As nighttime 
visual monitoring is generally considered to be ineffective at any 
height, the EGTTR missions will incorporate the TR.

Ramp-Up Procedures

    The rationale for requiring ramp-up procedures is that this process 
may allow animals to perceive steadily increasing noise levels and to 
react, if necessary, before the noise reaches a threshold of 
significance. The AC-130 gunship's weapons are used in two activity 
phases. First, the guns are checked for functionality and calibrated. 
This step requires an abbreviated period of live fire. After the guns 
are determined to be ready for use, the mission proceeds under various 
test and training scenarios. This second phase involves a more extended 
period of live fire and can incorporate use of one or any combination 
of the munitions available (25-, 40-, and 105-mm rounds). The ramp-up 
procedure shall be required for the initial gun calibration, and, after 
this phase, the guns may be fired in any order. Eglin AFB and NMFS 
believe this process will allow marine species the opportunity to 
respond to increasing noise levels. If an animal leaves the area during 
ramp-up, it is unlikely to return while the live-fire mission is 
proceeding. This protocol allows a more realistic training experience. 
In combat situations, gunship crews would not likely fire the complete 
ammunition load of a given caliber gun before proceeding to another 
gun. Rather, a combination of guns would likely be used as required by 
an evolving situation. An additional benefit of this protocol is that 
mechanical or ammunition problems on an individual gun can be resolved 
while live fire continues with functioning weapons. This also 
diminishes the possibility of a lengthy pause in live fire, which, if 
greater than 10 min, would necessitate Eglin's re-initiation of 
protected species surveys (described next).

Other Mitigation

    In addition to the development of the TR, the visual mitigation, 
and the ramp-up procedures already described in this document, 
additional mitigation measures to protect marine life were included in 
the 2006, 2008, 2009, and 2010 IHAs and are proposed for inclusion in 
this proposed IHA. These requirements include:
    (1) If daytime weather and/or sea conditions preclude adequate 
aerial surveillance for detecting marine mammals and other marine life, 
A-S gunnery exercises must be delayed until adequate sea conditions 
exist for aerial surveillance to be undertaken. Daytime test firing 
will be conducted only when sea surface conditions are sea state 4 or 
less on the Beaufort scale.
    (2) Prior to each firing event, the aircraft crew will conduct a 
visual survey of the 5-nm (9.3-km) wide prospective target area to 
attempt to sight any marine mammals that may be present (the crew will 
do the same for sea turtles and Sargassum rafts). The AC-130 gunship 
will conduct at least two complete orbits at a minimum safe airspeed 
around a prospective target area at a maximum altitude of 6,000 ft 
(1,829 m). Provided marine mammals (and other protected species) are 
not detected, the AC-130 can then continue orbiting the selected target 
point as it climbs to the mission testing altitude. During the low 
altitude orbits and the climb to testing altitude, the aircraft crew 
will visually scan the sea surface within the aircraft's orbit circle 
for the presence of marine mammals. Primary emphasis for the surface 
scan will be upon the flight crew in the cockpit and personnel 
stationed in the tail observer bubble and starboard viewing window. The 
AC-130's optical and electronic sensors will also be employed for 
target clearance. If any marine mammals are detected within the AC-
130's orbit circle, either during initial clearance or after 
commencement of live firing, the aircraft will relocate to another 
target and repeat the clearance procedures. If multiple firing events 
occur within the same flight, these clearance procedures will precede 
each event.
    (3) The aircrews of the A-S gunnery missions will initiate location 
and surveillance of a suitable firing site immediately after exiting 
U.S. territorial waters (less than or equal to 12 nm (22 km)). This 
would potentially restrict most gunnery activities to the shallower 
continental shelf waters of the GOM where marine mammal densities are 
typically lower, and thus potentially avoid the slope waters where the 
more sensitive species (e.g., endangered sperm whales) typically 
reside.
    (4) Observations will be accomplished using all-light TV, IR 
sensors, and visual means for at least 60 min prior to each exercise.
    (5) Aircrews will utilize visual, night vision goggles, and other 
onboard sensors to search for marine mammals while performing area 
clearance procedures during night-time pre-mission activities.
    (6) If any marine mammals are sighted during pre-mission surveys or 
during the mission, activities will be immediately halted until the 
area is clear of all marine mammals for 60 min or the mission location 
relocated and resurveyed.
    (7) If post-detonation surveys determine that an injury or lethal 
take of a marine mammal has occurred, the test procedure and the 
monitoring methods must be reviewed with NMFS and appropriate changes 
must be made, prior to conducting the next air-to-surface gunnery 
exercise.
    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals;
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned; and
     The practicability of the measure for applicant 
implementation, including consideration of personnel safety, 
practicability of implementation, and impact on the effectiveness of 
the military-readiness activity.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammal species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance, while also 
considering personnel safety, practicability of implementation, and 
impact on the effectiveness of the military-readiness activity.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must, where applicable, 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 ITAs 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

[[Page 43273]]

expected to be present in the proposed action area.
    The Incidental Take Statement in NMFS' Biological Opinion on this 
action required certain monitoring measures to protect marine life. 
NMFS also imposed these same requirements, as well as additional ones, 
under Eglin AFB's 2006, 2008, and 2010 IHAs as they related to marine 
mammals. NMFS is proposing to include these same measures in the 2011 
IHA (if issued). They are:
    (1) The A-S gunnery mission aircrews will participate in the marine 
mammal species observation training. Each crew member will be required 
to complete the training prior to participating in a gunnery mission. 
Observers will receive training in protected species survey and 
identification techniques.
    (2) Aircrews will initiate the post-mission clearance procedures 
beginning at the operational altitude of approximately 15,000 to 20,000 
ft (4,572 to 6,096 m) elevation, and then initiate a spiraling descent 
down to an observation altitude of approximately 6,000 ft (1,829 m) 
elevation. Rates of descent will occur over a 3 to 5 min time frame.
    (3) Eglin will track their use of the EGTTR for test firing 
missions and protected species observations, through the use of mission 
reporting forms.
    (4) A-S gunnery missions will coordinate with next-day flight 
activities to provide supplemental post-mission observations for marine 
mammals in the operations area of the previous day.
    (5) A summary annual report of marine mammal observations and A-S 
activities will be submitted to the NMFS Southeast Regional Office 
(SERO) and the Office of Protected Resources either at the time of a 
request for renewal of an IHA or 90 days after expiration of the 
current IHA if a new IHA is not requested. This annual report must 
include the following information: (i) Date and time of each air-to-
surface gunnery exercise; (ii) a complete description of the pre-
exercise and post-exercise activities related to mitigating and 
monitoring the effects of A-S gunnery exercises on marine mammal 
populations; (iii) results of the monitoring program, including numbers 
by species/stock of any marine mammals noted injured or killed as a 
result of the gunnery exercises and number of marine mammals (by 
species if possible) that may have been harassed due to presence within 
the 5-nm activity zone; and (iv) a detailed assessment of the 
effectiveness of sensor-based monitoring in detecting marine mammals in 
the area of A-S gunnery operations.
    (6) If any dead or injured marine mammals are observed or detected 
prior to testing, or injured or killed during live fire, a report must 
be made to NMFS by the following business day.
    (7) Any unauthorized takes of marine mammals (i.e., injury or 
mortality) must be immediately reported to NMFS and to the respective 
stranding network representative.
Estimated Take by Incidental Harassment
    As it applies to a ``military readiness activity'', the definition 
of harassment is (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].

    Take by Level B harassment is anticipated as a result of the A-S 
gunnery mission activities. The exercises are expected to only affect 
animals at or very near the surface of the water. Cetaceans in the 
vicinity of the exercises may incur temporary changes in behavior, and/
or temporary changes in their hearing thresholds. Based on the proposed 
mitigation and monitoring measures described earlier in this document, 
no serious injury or mortality of marine mammals is anticipated as a 
result of the A-S gunnery mission activities, and no takes by serious 
injury or mortality are proposed to be authorized.
    Estimating the impacts to marine mammals from underwater 
detonations is difficult due to complexities of the physics of 
explosive sound under water and the limited understanding with respect 
to hearing in marine mammals. Detailed assessments were made in the 
notice for the 2006 and 2008 IHAs on this action (71 FR 27695, May 12, 
2006; 73 FR 78318, December 22, 2008) and are repeated in this Federal 
Register notice. These assessments used, and improved upon, the 
criteria and thresholds for marine mammal impacts that were developed 
for the shock trials of the USS SEAWOLF and the USS WINSTON S. 
CHURCHILL (DDG-81) (Navy, 1998; 2001). The criteria and thresholds used 
in those actions were adopted by NMFS for use in calculating incidental 
takes from explosives. Criteria for assessing impacts from Eglin AFB's 
A-S gunnery exercises include: (1) Mortality, as determined by exposure 
to a certain level of positive impulse pressure (expressed as pounds 
per square inch per millisecond or psi-msec); (2) injury, both hearing-
related and non-hearing related; and (3) harassment, as determined by a 
temporary loss of some hearing ability and behavioral reactions. Due to 
the small amounts of net explosive weight (NEW) for each of the rounds 
fired in the EGTTR and the mitigation measures proposed by NMFS for 
implementation, mortality resulting from the resulting sounds generated 
into the water column from detonations was determined to be highly 
unlikely and was not considered further by Eglin AFB or NMFS.
    Permanent hearing loss is considered an injury and is termed 
permanent threshold shift (PTS). NMFS, therefore, categorizes PTS as 
Level A harassment. Temporary loss of hearing ability is termed TTS, 
meaning a temporary reduction of hearing sensitivity which abates 
following noise exposure. TTS is considered non-injurious and is 
categorized as Level B harassment. NMFS recognizes dual criteria for 
TTS, one based on peak pressure and one based on the greatest \1/3\ 
octave sound exposure level (SEL) or energy flux density level (EFDL), 
with the more conservative (i.e., larger) of the two criteria being 
selected for impacts analysis (note: SEL and EFDL are used 
interchangeably, but with increasing scientific preference for SEL). 
The peak pressure metric used in previous shock trials to represent TTS 
was 12 pounds per square inch (psi) which, for the NEW used, resulted 
in a zone of possible Level B harassment approximately equal to that 
obtained by using a 182 decibel (dB) re 1 microPa\2\-s, total EFDL/SEL 
metric. The 12-psi metric is largely based on anatomical studies and 
extrapolations from terrestrial mammal data (see Ketten, 1995; Navy, 
1999 (Appendix E, CHURCHILL FEIS; and 70 FR 48675 (August 19, 2005)) 
for background information). However, the results of a more recent 
investigation involving marine mammals suggest that, for small charges, 
the 12-psi metric is not an adequate predictor of the onset of TTS but 
that one should use 23 psi. This explanation is provided earlier in 
this document.
    Documented behavioral reactions occur at noise levels below those 
considered to cause TTS in marine mammals (Finneran et al., 2002; 
Schlundt et al., 2000; Finneran and Schlundt, 2004). In controlled 
experimental situations, behavioral effects are typically defined as

[[Page 43274]]

alterations of trained behaviors. Behavioral effects in wild animals 
are more difficult to define but may include decreased ability to feed, 
communicate, migrate, or reproduce. Abandonment of an area due to 
repeated noise exposure is also considered a behavioral effect. 
Analyses in other sections of this document refer to such behavioral 
effects as ``sub-TTS Level B harassment.'' Schlundt et al. (2000) 
exposed bottlenose dolphins and beluga whales to various pure-tone 
sound frequencies and intensities in order to measure underwater 
hearing thresholds. Masking is considered to have occurred because of 
the ambient noise environment in which the experiments took place. 
Sound levels were progressively increased until behavioral alterations 
were noted (at which point the onset of TTS was presumed). It was found 
that decreasing the sound intensity by 4 to 6 dB greatly decreased the 
occurrence of anomalous behaviors. The lowest sound pressure levels, 
over all frequencies, at which altered behaviors were observed, ranged 
from 178 to 193 dB re 1 [micro]Pa for the bottlenose dolphins and from 
180 to 196 dB re 1 [micro]Pa for the beluga whales. Thus, it is 
reasonable to consider that sub-TTS (behavioral) effects occur at 
approximately 6 dB below the TTS-inducing sound level, or at 
approximately 176 dB in the greatest \1/3\ octave band EFDL/SEL.
    Table 3 (earlier in this document) summarizes the relevant 
thresholds for levels of noise that may result in Level A harassment 
(injury) or Level B harassment via TTS or behavioral disturbance to 
marine mammals. Mortality and injury thresholds are designed to be 
conservative by considering the impacts that would occur to the most 
sensitive life stage (e.g., a dolphin calf). Table 4 provides the 
estimated ZOI radii for the EGTTR ordnance. At this time, there are no 
empirical data or information that would allow NMFS to establish a peak 
pressure criterion for sub-TTS behavioral disruption.

              Table 4--Estimated Range for a Zone of Impact (ZOI) Distance for the EGTTR Ordnance.
----------------------------------------------------------------------------------------------------------------
                                                                      Level B         Level B         Level B
                                                      Level A     harassment non- harassment non- harassment non-
                   Expendable                       harassment    injurious (182   injurious (23  injurious (177
                                                  injurious (205    dB) EFD for    psi) for TTS     dB) EFD for
                                                    dB) EFD (m)       TTS (m)           (m)        behavior (m)
----------------------------------------------------------------------------------------------------------------
105-mm FU.......................................           22.81          158.26          216.37          281.78
105-mm TR.......................................            8.86           49.79           91.45           90.46
40-mm HE........................................           12.52           74.27          123.83          142.11
25-mm HE........................................               0           23.82           52.72           41.24
----------------------------------------------------------------------------------------------------------------
FU = Full-up; TR = Training Round; HE = High Explosive.
 

    As mentioned previously, the EGTTR live fire events are continuous 
events with pauses during the firing usually well under a minute and 
rarely from 2 to 5 min. Live fire typically occurs within a 30 min time 
frame, including all ordnance fired: 25 mm; 40 mm; and where the 105-mm 
ordnance are fired as separate rounds with up to 30-s intervals, the 
25-mm and the 40-mm are often fired in multiple bursts. These bursts 
include multiple rounds (20 to 100) within a 2- to 10-s time frame. 
Eglin notes that even if animal avoidance once firing commences is not 
considered, the average swim speed (1.5 m/s) of an animal would not 
allow sufficient time for new animals to re-enter the Level B 
harassment ZOI (23 psi) within the time frame of a single burst. As 
such, only the peak pressure of a single round is measured per burst 
and experienced at a given distance (53 m (161 ft; 25-mm HE), 124 m 
(400 ft; 40-mm HE)).
    It is assumed that the average swim speed per cetacean is 
approximately 3 knots or 1.5 m/sec. As a conservative scenario, Eglin 
assumes that there is one animal present within or near the 282 m Level 
B behavioral harassment ZOI (FU 105-mm round ZOI), which is the largest 
ZOI evaluated in this analysis, at the time that the 105-mm live firing 
begins. The overall marine mammal density determination (see Table 3-1 
in the IHA application) assumes a uniform distribution of approximately 
1.4 animals per km \2\, which results in a distance of approximately 
843 m between each animal (all species) on average. At this density 
distribution and typical swim speed, the next available cetacean would 
approach the perimeter of the 216 m (709 ft) ZOI (23-psi TTS ZOI) in 
approximately 9.4 min, assuming a straight line path and a continuous 
swim profile in the direction of the gunnery exercises. With live-fire 
events for the 105-mm occurring at a rate of approximately 2 rounds/
min, approximately 18 to 19 rounds of the 30 round load (or 
approximately two-thirds of the total load) would be expended within 
the 9.4 minute time frame. Based on this scenario, one cetacean would 
be present in the ZOI at the beginning of live fire, and an additional 
cetacean would enter the ZOI after 9.4 minutes. The remaining 11 to 12 
rounds would be expended in approximately 6 minutes, which would not be 
enough time for an additional animal to enter the ZOI. However, 
allowing for potential pauses in firing, it may be possible for one 
additional animal to enter the ZOI, so that up to three cetaceans could 
be exposed to the 23-psi TTS threshold associated with 105-mm FU 
ordnance during a typical mission. Therefore, one cetacean would be 
within the ZOI for every 10 rounds fired (30 divided by 3), on average. 
The number of rounds required to result in one exposure is considered 
an event; therefore, the total number of rounds fired per year is 
divided by 10. It should be noted that this scenario does not take into 
account the possibility of marine mammals avoiding the area once firing 
begins.
    Based on this discussion, Table 5 in this Federal Register document 
provides Eglin AFB's estimates of the annual number of marine mammals, 
by species, potentially taken by Level A harassment and Level B 
harassment, by the gunnery mission noise. It should be noted that these 
estimates are derived without consideration of the effectiveness of 
Eglin AFB's proposed mitigation measures (except use of the TR), which 
are discussed earlier in this document. As indicated in Table 5, Eglin 
AFB and NMFS estimate that approximately three marine mammals could 
potentially be exposed to injurious Level A harassment noise levels 
(205 dB re 1 [mu]Pa \2\ -s or higher); however, neither NMFS nor Eglin 
AFB

[[Page 43275]]

anticipate that injurious Level A harassment will result from the 
proposed A-S gunnery missions because of Eglin AFB's standard 
mitigation measures, and NMFS is not proposing to authorize Level A 
takes of marine mammals.
    Approximately 212 marine mammals would be exposed annually to non-
injurious (TTS) Level B harassment associated with the 182 dB re 1 
[mu]Pa \2\-s threshold. Because these gunnery exercises result in 
multiple detonations, they have the potential to also result in a 
temporary modification in behavior by marine mammals at levels below 
TTS. Based on Eglin AFB and NMFS' estimates, up to 694 marine mammals 
may experience a behavioral response to these exercises during the time 
frame of an IHA (see Table 5). Finally, while one would generally 
expect the threshold for behavioral modification to be lower than that 
causing TTS, due to a lack of empirical information and data, a dual 
criteria for Level B behavioral harassment cannot be developed. 
However, to ensure that takings are covered by this IHA, NMFS estimates 
that approximately 906 marine mammals of five stocks may incur Level B 
(harassment) takes during the 1-year period of an IHA. NMFS has 
preliminarily determined that this number will be significantly lower 
due to the expected effectiveness of the mitigation measures proposed 
for inclusion in the IHA (if issued).

Negligible Impact and Preliminary Determination

    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.'' In making a negligible impact determination, 
NMFS considers a variety of factors, including but not limited to: (1) 
The number of anticipated mortalities; (2) the number and nature of 
anticipated injuries; (3) the number, nature, and intensity, and 
duration of Level B harassment; and (4) the context in which the takes 
occur.
    The takes from Level B harassment will be due to behavioral 
disturbance and TTS. Although activities would be permitted to occur 
year-round and can last for approximately 5 to 6 hours at a time, the 
actual live-fire portion of the exercise usually only lasts for 90 to 
120 min. It is possible that some individuals may be taken more than 
once if those individuals are located in the exercise area on two 
different days when exercises are occurring. However, multiple 
exposures are not anticipated to have effects beyond Level B 
harassment.

[[Page 43276]]

[GRAPHIC] [TIFF OMITTED] TN20JY11.000

    Of the 21 marine mammal species or stocks that may be in the 
vicinity of the EGTTR gunnery mission activities, only the sperm whale 
is listed as endangered under the ESA and as depleted under the MMPA. 
Sperm whale occurrence in the area of the proposed activity is unlikely 
because almost all reported sightings have occurred in water depths 
greater than 200 m. Occurrence in the deeper portions of W-151 is 
possible, although based on reported sightings locations, density is 
expected to low. Therefore, Eglin AFB has not requested and NMFS has 
not proposed the issuance of take authorizations for this species. 
While animals may be impacted in the immediate vicinity of the 
activity,

[[Page 43277]]

because of the small ZOIs (compared to the vast size of the GOM 
ecosystem where these species live) and the small amounts of explosives 
used in the A-S gunnery exercises, NMFS has preliminarily determined 
that there will not be a substantial impact on marine mammals or on the 
normal functioning of the nearshore or offshore GOM ecosystems. The 
proposed activity is not expected to impact rates of recruitment or 
survival of marine mammals since neither mortality (which would remove 
individuals from the population) nor injury are anticipated to occur. 
Although the proposed activity is anticipated to result in Level B 
harassment of marine mammals (both by behavioral disturbance and TTS), 
the level of harassment is not anticipated to impact rates of 
recruitment or survival of marine mammals.
    Additionally, the mitigation and monitoring measures proposed to be 
implemented (described earlier in this document) are expected to 
further minimize the potential for harassment. The protected species 
surveys will require Eglin AFB to search the area for marine mammals, 
and if any are found in the live fire area, then the exercise must be 
suspended until the animal(s) has left the area or relocated. Moreover, 
the aircrews of the A-S gunnery missions will initiate location and 
surveillance of a suitable firing site immediately after exiting U.S. 
territorial waters (less than or equal to 12 nm (22 km)). This would 
potentially restrict most gunnery activities to the shallower 
continental shelf waters of the GOM where marine mammal densities are 
typically lower, and thus potentially avoid the slope waters where the 
more sensitive species (e.g., endangered sperm whales) typically 
reside.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that Eglin AFB's A-S gunnery mission 
exercises will result in the incidental take of marine mammals, by 
Level B harassment only, and that the total taking from the A-S gunnery 
mission exercises will have a negligible impact on the affected species 
or stocks.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

    There are no relevant subsistence uses of marine mammals implicated 
by this action. Therefore, NMFS has preliminarily determined that the 
total taking of affected species or stocks would not have an 
unmitigable adverse impact on the availability of such species or 
stocks for taking for subsistence purposes.

Endangered Species Act (ESA)

    A Biological Opinion issued by NMFS on October 20, 2004, concluded 
that the A-S gunnery exercises in the EGT