Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Conducting Air-to-Surface Gunnery Missions in the Gulf of Mexico, 53474-53486 [E9-24842]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 74, Number 200 (Monday, October 19, 2009)]
[Notices]
[Pages 53474-53486]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-24842]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XS20


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 MMPA, NMFS is requesting comments 
on its proposal to issue an IHA to Eglin AFB to take, by Level B 
harassment only, 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 November 
18, 2009.

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 20910-3225. The mailbox address for 
providing e-mail comments is PR1.0648-XS20@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: Candace Nachman, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 156.

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

[[Page 53475]]

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 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 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 is effective through December 
10, 2009.
    On February 17, 2009, NMFS received a request from Eglin AFB for a 
renewal of its IHA, which is valid through December 10, 2009. No 
modifications to the activity location, the mission activities, or the 
mitigation and monitoring measures that are required under the 2008-
2009 IHA have been requested by Eglin AFB. Therefore, these activities 
are identical to what has been described previously (73 FR 78318, 
December 22, 2008). 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. Sixteen marine mammal species or stocks are considered for 
taking by Level B harassment incidental to Eglin AFB's A-S activities 
and include: Bryde's whale (Balaenoptera brydei); sperm whale (Physeter 
macrocephalus); 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); Cuvier's beaked whale (Ziphius cavirostris); Clymene 
dolphin (S. clymene); spinner dolphin (S. longirostris); striped 
dolphin (S. coeruleoalba); false killer whale (Pseudorca crassidens); 
pygmy killer whale (Feresa attenuata); Risso's dolphin (Grampus 
griseus); rough-toothed dolphin (Steno bredanensis); and short-finned 
pilot whale (Globicephala macrorhynchus).

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 2003 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 December 11, 2009 (after 
expiration of the current IHA) through December 10, 2010.
    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

[[Page 53476]]

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 hr without 
refueling and 6 hr 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 hr of dry fire 
(no ordnance expended) and includes transition time; (3) 1.5 to 2 hr 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).
    The guns are fired during the live-fire phase of the mission. The 
actual firing can last from 30 min to 1.5 hr 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 
an Mk-25 flare, 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 500 to 1,000 rounds. These rounds are fired in short 
bursts. 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 Impact (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 of a typical mission includes 
approximately 10 s with approximately 20 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 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 of a typical mission includes approximately 
20 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 (90 m (295 ft) for the 105-mm TR and 216 m (709 ft) for 
the 105-mm FU).
    As described in Eglin's 2003 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 1,742. As shown in detail in Tables 1 and 2, Eglin 
proposes to conduct a total of 28 daytime missions and 263 nighttime 
missions annually, expending 3,832 rounds in the daytime and 30,802 
rounds at night (242 105-mm FU and 1,500 rounds would be the 105-mm 
TR).

                                           Table 1--Summary of Daytime Gunnery Testing Operations in the EGTTR
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                                                                                                             Baseline
        Test area                   Category                 Expendable                 Condition           quantity of      Number of       Number of
                                                                                                            expendables      missions         events
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W-151A...................  GUN......................  105 mm HE...............  LIVE....................             128               6              18
                                                      25 mm HEI...............  LIVE....................           1,275               1               1
                                                      40 mm HEI...............  LIVE....................             536               6              18
W-151B...................  GUN......................  105 mm HE...............  LIVE....................              46               2               6
                                                      25 mm HEI...............  LIVE....................             294               1               1
                                                      40 mm HEI...............  LIVE....................             146               1               3
W-151C...................  GUN......................  105 mm HE...............  LIVE....................              10               1               3

[[Page 53477]]

 
                                                      25 mm HEI...............  LIVE....................             142               1               1
                                                      40 mm HEI...............  LIVE....................              50               1               3
W-151D...................  GUN......................  105 mm HE...............  LIVE....................              39               2               6
                                                      25 mm HEI...............  LIVE....................             567               1               1
                                                      40 mm HEI...............  LIVE....................             198               2               6
W-151S...................  GUN......................  105 mm HE...............  LIVE....................              19               1               3
                                                      25 mm HEI...............  LIVE....................             283               1               1
                                                      40 mm HEI...............  LIVE....................              99               1               3
                                                                                                         -----------------------------------------------
    Total................  .........................  ........................  ........................           3,832              28              74
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                                         Table 2--Summary of Nighttime Gunnery Training Operations in the EGTTR
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                                                                                                              Alt. 3         Number of       Number of
        Test area                   Category                 Expendable                 Condition            quantity        missions         events
--------------------------------------------------------------------------------------------------------------------------------------------------------
W-151A...................  GUN......................  105 mm TR...............  LIVE....................             902              45             135
                                                      25 mm HEI...............  LIVE....................           7,864               8               8
                                                      40 mm HEI...............  LIVE....................           9,811             102             306
W-151B...................  GUN......................  105 mm TR...............  LIVE....................             255              13              39
                                                      25 mm HEI...............  LIVE....................           1,452               2               2
                                                      40 mm HEI...............  LIVE....................           3,023              31              93
W-151C...................  GUN......................  105 mm TR...............  LIVE....................             197               9              36
                                                      25 mm HEI...............  LIVE....................           2,301               2               2
                                                      40 mm HEI...............  LIVE....................           2,302              24              72
W-151D...................  GUN......................  105 mm TR...............  LIVE....................             133               7              21
                                                      25 mm HEI...............  LIVE....................             830               1               1
                                                      40 mm HEI...............  LIVE....................           1,583              16              48
W-151S...................  GUN......................  105 mm TR...............  LIVE....................              13               1               3
                                                      25 mm HEI...............  LIVE....................              54               1               1
                                                      40 mm HEI...............  LIVE....................              82               1               3
                                                                                                         -----------------------------------------------
    Total................  .........................  ........................  ........................          30,802             263             770
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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 within the proposed action area, the 
EGTTR. These species are the Bryde's whale, sperm whale, dwarf sperm 
whale, pygmy sperm whale, Atlantic bottlenose dolphin, Atlantic spotted 
dolphin, pantropical spotted dolphin, Blainville's beaked whale 
(Mesoplodon densirostris), Cuvier's beaked whale, Gervais' beaked whale 
(M. europaeus), Clymene dolphin, spinner dolphin, striped dolphin, 
killer whale (Orcinus orca), false killer whale, pygmy killer whale, 
Risso's dolphin, Fraser's dolphin (Lagenodelphis hosei), melon-headed 
whale (Peponocephala electra), rough-toothed dolphin, and short-finned 
pilot whale. 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. 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 (Waring et al., 2009). This latter document is available at: 
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 include: Atlantic bottlenose dolphin; Atlantic 
spotted dolphin; pantropical spotted dolphin; spinner dolphin; striped 
dolphin; Risso's dolphin; Clymene dolphin; and dwarf and pygmy sperm 
whales. Blainville's beaked whale, Gervais' beaked whale, killer whale, 
Fraser's dolphin, 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 five species are not considered further in 
this proposed IHA Federal Register notice.
    Cetacean abundance estimates for the study area are derived from 
GulfCet II (Davis et al., 2000) aerial surveys of the continental shelf 
within the Minerals Management Service (MMS) Eastern Planning Area, an 
area of 70,470 km\2\. Texas A&M University and NMFS conducted the 
surveys from 1996 to 1998. Abundance and density data from the aerial 
survey portion of the survey best reflect the occurrence of cetaceans 
within the EGTTR, given that the survey area overlaps approximately 
one-third of the EGTTR and nearly the entire continental shelf region 
of the EGTTR where military activity is highest. Cetaceans inhabiting 
the study area may be grouped as odontocetes (toothed whales, including 
dolphins) or mysticetes (baleen whales). Most of the cetaceans 
occurring in the Gulf are odontocetes. Very few baleen whales exist in 
the Gulf and most would not be expected to occur within the study area 
given the known distribution of these species. Table 3-5 in the USAF 
2002 PEA lists the abundance and density of cetacean populations in the 
northern

[[Page 53478]]

GOM, as estimated from NMFS aerial surveys. However, in order to 
provide better species conservation and protection, the species density 
estimate data were adjusted by incorporating: (1) Temporal and spatial 
variations; (2) surfaced and submerged variations; and (3) overall 
density estimate confidence (Table 3-1 in Eglin AFB's 2003 application; 
see ADDRESSES).
    The GulfCet II aerial surveys identified different density 
estimates of marine mammals for the shelf and slope geographic 
locations. Accordingly, the greatest species density estimate available 
for any given location was utilized for conservative impact 
assessments. The final adjusted density incorporates marine mammal 
submergence factors and a confidence level of the density estimates. 
The GulfCet II surveys focus on enumerating animals detected at the 
ocean surface and therefore do not account for submerged animals. The 
percent time that an animal is submerged versus at the surface was 
obtained from Moore and Clarke (1998), and the density estimates were 
adjusted accordingly. Additionally, the standard deviations of the 
densities were calculated, and the information was used to provide an 
approximately 99 percent confidence level for the adjusted densities. 
The adjusted densities are outlined in Table 3-1 in Eglin AFB's 2003 
application.

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; a 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 [mu]Pa p-p (peak to peak). This 
sound pressure level (SPL) is equivalent 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 [mu]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 inert bombs, gunnery 
ammunition, and shrapnel from live missiles falling into the water. 
Marine mammals swimming at the surface could potentially be injured or 
killed by projectiles and falling debris if not sighted and firing 
discontinued. Mainly due to the comparatively large number of rounds 
expended, small arms gunnery operations offers a worst-case scenario 
for evaluating DPI of EGTTR operations. Some small-arms gunnery rounds 
contain small amounts of explosives, but the majority do not. However, 
the possibility of DPI to marine mammals is considered highly unlikely. 
Therefore, the risk of injury or mortality is low. The assumptions made 
by Eglin AFB for DPI calculations can be found in the USAF 2002 Final 
PEA under the analysis for Alternative 1. Approximately 606 small-arms 
gunnery firing events comprise the baseline level of potential DPI 
events, as shown here in Table 4. DPI impacts are only anticipated to 
affect marine species at or very near the ocean surface.
    Mortality resulting from DPI or 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 because of the 
small amounts of net explosive weight for each of the rounds fired in 
the EGTTR and the proposed mitigation measures discussed later in this 
document (see ``Proposed Mitigation'' section). Impacts to marine 
mammals are anticipated to be limited to Level B harassment in the form 
of temporary changes in behavior or temporary changes in hearing 
thresholds (i.e., TTS).

  Table 4--EGTTR Air-to-Surface Gunnery/Small Arms Operations as Events
------------------------------------------------------------------------
                                         Percentage of      Number of
         Activity/EGTTR event                events           events
------------------------------------------------------------------------
Small Arms 50 Cal Ball Events.........             16.3               99
Small Arms 5.56 Linked Events.........              0.8                5
Small Arms 7.62 mm Ball Events........             82.8              502
                                                        ----------------

[[Page 53479]]

 
Total Baseline--Small Caliber Events..              100              606
------------------------------------------------------------------------

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 of a lighted environment 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 
Section 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 current IHA (73 FR 78318, December 22, 
2008). These measures are virtually identical to the mitigation 
measures that were required in 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 
suspended until the 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 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

[[Page 53480]]

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 and 2008 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 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 and 2008 IHAs as they related to marine mammals. 
NMFS is proposing to include these same measures in the 2009 IHA (if 
issued). They are:
    (1) The A-S gunnery mission aircrews will participate in the marine 
mammal species observation training. Designated crew members will be 
selected to receive training as protected species observers. 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-

[[Page 53481]]

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].

    Only 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 
mitigation and monitoring measures described earlier in this document, 
no injury or mortality of marine mammals is anticipated as a result of 
the A-S gunnery mission activities.
    DPI impacts are only anticipated to affect marine species at or 
very near the ocean surface. As a result, in order to calculate 
impacts, Eglin used corrected species densities (see Table 4-23 in the 
USAF's Final PEA) to reflect the surface interval population, which is 
approximately 10 percent of densities calculated for distribution in 
the total water column. As shown in Table 5 in this document (and 
thereby correcting PEA Table 4-23), the impacts to marine mammals 
swimming at the surface that could potentially be injured or killed by 
projectiles and falling debris was determined to be an average of 
0.2059 marine mammals per year. However, NMFS believes that the 
mitigation measures that Eglin proposes under this action would 
significantly reduce even these low levels.
    In addition to small arms, Eglin calculated the potential for other 
non-explosive items (bombs, missiles, and drones) to impact marine 
mammals. The number of annual events expected are 551 bombs, 1,183 
missiles, and 99 drones. As shown in the 2002 Final PEA and Table 6 in 
this document, the potential for any non-small arms/non-gunnery DPI to 
marine mammals is extremely remote and can, therefore, be discounted.
    Similar to non-small arms/non-gunnery DPI impacts, DPI impacts from 
gunnery activities may also affect marine mammals in the surface zone. 
Again, DPI impacts are anticipated to affect only marine mammals at or 
near the ocean surface and not animals that are submerged at the time. 
Accordingly, the density estimates have been adjusted to indicate 
surface animals only being potentially affected. Using the firing 
methodology explained earlier in this document, Tables 7 and 8 
demonstrate that the potential for any DPI from gunnery activities are 
extremely remote and can be discounted. Using the largest round (105 
mm), it would take approximately 120 yr to impact a marine mammal from 
daytime gunnery activities and approximately 27 yr to impact a marine 
mammal from nighttime gunnery activities.

                   Table 5--Potential Small Arms DPI Impacts (Annual) to Marine Mammal Species
----------------------------------------------------------------------------------------------------------------
                                                     Adjusted
                                      Density         density       Impact zone     Animals in       Years to
             Species                (/     (/    area (km\2\)     impact zone      impact 1
                                      km\2\)          km\2\)                        ()       animal
----------------------------------------------------------------------------------------------------------------
Cetaceans.......................           4.381          0.4381        0.047874        2.10E-02              48
Threatened and Endangered                  0.011          0.0011        0.047874        5.27E-05          18,989
 Cetaceans......................
----------------------------------------------------------------------------------------------------------------


           Table 6--Potential Non-Small Arms/Non-Gunnery DPI Impacts (Annual) to Marine Mammal Species
----------------------------------------------------------------------------------------------------------------
                                                     Adjusted
                                      Density         density       Impact zone     Animals in       Years to
             Species                (/     (/    area (km\2\)     impact zone      impact 1
                                      km\2\)          km\2\)                        ()       animal
----------------------------------------------------------------------------------------------------------------
Cetaceans.......................           4.381          0.4381         0.00688     0.003014128             332
Threatened and Endangered                  0.011          0.0011         0.00688     0.000007568         132,135
 Cetaceans......................
----------------------------------------------------------------------------------------------------------------


[[Page 53482]]


                                       Table 7--Potential Daytime Gunnery DPI Impacts (Annual) to Marine Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Adjusted                                                        Years to
                                                              Density         density       Impact zone      Number of      Animals in       impact 1
                   Species/shell size                     (/km)    (/    area (km\2\)   events ()         ()         i>)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetacea.................................................           4.381          0.4381       .00007854              26      .000881198           1,135
(25 mm).................................................
Cetacea.................................................           4.381          0.4381       .00007854              51      .001770311             565
(40 mm).................................................
Cetacea.................................................           4.381          0.4381       .00007854             242      .008326827             120
(105mm).................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                      Table 8--Potential Nighttime Gunnery DPI Impacts (Annual) to Marine Cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                             Adjusted                                                        Years to
                                                              Density         density       Impact zone      Number of      Animals in       impact 1
                   Species/shell size                     (/km)    (/    area (km\2\)   events ()         ()         i>)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cetacea (25 mm).........................................           4.381          0.4381       .00007854             125      .004287972             233
Cetacea (40 mm).........................................           4.381          0.4381       .00007854             723      .024873814              40
Cetacea (105mm).........................................           4.381          0.4381       .00007854            1061      .036507285              27
--------------------------------------------------------------------------------------------------------------------------------------------------------

    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. 
Similar to the effects from DPI, 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 either DPI or 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 
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 
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 [mu]Pa for the bottlenose dolphins and from 180 
to 196 dB re 1 [mu]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.

[[Page 53483]]

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 9 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 9--Estimated Range for a Zone of Impact (ZOI) Distance for the EGTTR Ordnance
----------------------------------------------------------------------------------------------------------------
                                                              Level B                               Level B
                                           Level A        harassment non-        Level B        h