Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Conducting Air-to-Surface Gunnery Missions in the Gulf of Mexico, 5045-5054 [2010-2017]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 75, Number 20 (Monday, February 1, 2010)]
[Notices]
[Pages 5045-5054]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-2017]


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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; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA) 
regulations, notification is hereby given that NMFS has issued an 
Incidental Harassment Authorization (IHA) to the U.S. Air Force (USAF), 
Eglin Air Force Base (Eglin AFB), 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.

DATES:  Effective January 27, 2010, through January 26, 2011.

ADDRESSES:  A copy of the authorization, 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 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, 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 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) (Public Law 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).
    On February 17, 2009, NMFS received a request from Eglin AFB for a 
renewal of its IHA, which expired on December 10, 2009. No 
modifications to the activity location, the mission activities, or the 
mitigation and monitoring measures required under the 2008-2009 IHA 
were 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 in the Notice of Proposed IHA (74 FR 53474, October 19, 2009) 
and later in this document, NMFS concurs with Eglin AFB 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 authorized 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

[[Page 5046]]

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 has made the 
IHA effective for an entire year from January 27, 2010, through January 
26, 2011. However, it should be noted that the level of activity has 
been far lower over the past few years than that predicted to be 
conducted by the USAF and by NMFS in this document for two reasons. 
First, many of the training crew members have been engaged in other 
activities in other parts of the world recently. Second, land ranges 
are the preferred method of live-fire training. In the last year, the 
USAF crews have not used the water ranges due to the excellent 
availability of land ranges. However, at some point in the future, land 
ranges may become more difficult to acquire, so water ranges are needed 
to ensure that aircrews can be fully trained. A detailed overview of 
the activity was provided in the Notice of Proposed IHA (74 FR 53474, 
October 19, 2009). No changes have been made to the proposed 
activities.

Comments and Responses

    A notice of receipt of Eglin AFB's application and NMFS' proposal 
to issue an IHA to the USAF, Eglin AFB, published in the Federal 
Register on October 19, 2009 (74 FR 53474). During the 30-day public 
comment period, NMFS received comments from the Marine Mammal 
Commission (MMC) and a member of the public. The comment from the 
private citizen opposed the issuance of an authorization without any 
specific substantiation for why such an authorization should not be 
issued. For the reasons set forth in this document, NMFS has determined 
that issuance of the authorization is appropriate. Following are the 
comments from the MMC and NMFS' responses.
    Comment 1: The MMC continues to question NMFS' conviction that 
temporary threshold shift (TTS), in all instances, constitutes no more 
than Level B harassment. The MMC recommends that NMFS revise its 
interpretation of TTS to indicate that it constitutes a temporary loss 
of function with consequences that may vary widely from negligible to 
biologically significant (e.g., compromised ability to forage, respond 
to reproductive cues, detect predators) depending on a variety of 
circumstances at the time the loss occurs, including the nature of the 
structural and functional hearing loss, the animals' behavioral 
response to the stimulus, its history, and environmental conditions; as 
such, and under certain circumstances, TTS may constitute Level A 
harassment.
    Response: NMFS agrees with the MMC that additional information 
regarding the range of effects from TTS should be added to the analysis 
of potential effects from the A-S gunnery mission exercises. That 
information has been added to the ``Potential Effects of the Specified 
Activity on Marine Mammals'' section found later in this document.
    Regarding the MMC's assertion that under certain circumstances TTS 
may constitute Level A harassment, this issue has been addressed 
several times by NMFS in the past (see for example 70 FR 48675, August 
19, 2005; and 66 FR 22450, May 4, 2001). As stated in those documents, 
the best scientific information available concludes that TTS is not an 
auditory injury, but is a temporary physiological reaction on the part 
of mammals to avoid an injury. The MMC, however, argues for considering 
TTS as both Level A harassment and Level B harassment based on 
conjecture on what might occur if a marine mammal with compromised 
hearing was at a disadvantage for survival. As noted previously, it is 
likely that marine mammals evolved certain behavioral responses to 
address natural loud noises in the environment (for example, billions 
of lightning strikes per year on the ocean at about 260 dB peak) by 
changes in conspecific spatial separation. For a more detailed analysis 
of why TTS is not considered Level A harassment, please refer to the 
Federal Register citations provided here, as well as Southall et al. 
(2007) for information on this subject.
    Comment 2: The MMC recommends that NMFS conduct a thorough review 
of the considerable information available on behavioral responses of 
marine mammals to sound before it moves forward with proposed 
regulations tied to the narrow findings of Schlundt et al. (2000) as 
the basis for estimating the number of animals likely to exhibit 
behavioral responses.
    Response: NMFS used the findings in Schlundt et al. (2000), as it 
was the best available science when developing the pressure criterion 
and estimating the level of take. However, NMFS will review any 
additional literature suggested by the MMC during the development of 
proposed regulations.
    Comment 3: The MMC reiterates its concern over the conclusion that 
no animals could be killed over the course of a year of such exercises. 
The MMC recommends that NMFS require performance testing of mitigation 
measures to assess their actual effectiveness at detecting marine 
mammals. The Navy is being asked to conduct similar evaluation 
programs, and doing so seems essential if our collective approach to 
such matters is to be considered science-based.
    Response: Since the MMC did not make any specific recommendations 
regarding the performance testing of mitigation measures to assess 
their actual effectiveness at detecting marine

[[Page 5047]]

mammals, NMFS is uncertain as to what exactly it is the MMC is 
recommending be done in this instance. Regarding the evaluation 
programs being conducted by the Navy, NMFS assumes that the MMC is 
referring to the effectiveness of visual observations by vessel-based 
marine mammal observers based on years of experience. The Navy's 
evaluation monitoring is in no way comparable to the activities being 
conducted here by Eglin AFB.
    The application addendum submitted by Eglin AFB in January 2007 
explained in detail the advantages and improved effectiveness of using 
the Infrared Detection Sets (IDS) system over typical night-vision 
devices and other visual observation systems. The IDS system is capable 
of detecting differences in temperature from thermal energy (heat) 
radiated from living bodies or from reflected and scattered thermal 
energy. Visible light is not necessary for object detection. This 
system is equally effective during day or night use. For a full 
explanation on the IDS system and its effectiveness, please refer to 
the 2008 IHA Notice of Issuance (73 FR 78318, December 22, 2008), Eglin 
AFB's 2007 application addendum, or NMFS' 2008 EA (see ADDRESSES). 
These documents also describe the effectiveness of this system at 6,000 
ft (1,829 m) altitude, which was a requested change by the USAF due to 
safety concerns for personnel if protected species surveys were flown 
at lower altitudes.
    Aircraft crew members are required to scan the testing area prior 
to the commencement of all A-S gunnery mission activities, for which 
optical and electronic sensors are required to be employed for target 
detection. If any marine mammals are detected within the AC-130's orbit 
circle, either during initial clearance or after commencement of live 
firing, the mission will be immediately halted and relocated as 
necessary or suspended until the marine mammal has left the area. If 
relocated to another target area, the clearance procedures must be 
repeated. Based on the analysis of effectiveness of the observation 
systems, NMFS has determined that flying the pre-mission surveys at an 
altitude of 6,000 ft (1,829 m) is a sufficient altitude to detect the 
presence of marine mammals. Since activities will not have occurred 
prior to these surveys, any sighted marine mammals will be assumed to 
either be alive or dead from a cause other than Eglin AFB's A-S 
activities.
    Regarding the effectiveness of differentiating between a live and a 
dead marine mammal during post-mission protected species surveys, 
unless there is significant physical damage, the operators/systems are 
not capable of determining between a non-moving live animal and a dead 
animal with no apparent physical damage. Typically, marine mammals do 
not exhibit the same levels of energy/heat transfer back into the 
environment that is associated with land animals due to their 
insulating fat layers. However, the USAF has stated that they would be 
able to see a wounded or recently killed marine mammal on or near the 
surface that is bleeding externally or with significant open wounds, as 
this would provide a heat signature that can be detected quite well by 
the IDS system.
    Additionally, the size of the wound, time elapsed since the injury 
was incurred, and orientation of the animal/wound are all factors 
determining whether or not one could see the gunnery-type wounds (such 
as bullet holes or fragmentation wounds). However, the weapons used 
during A-S exercises detonate on or very near the surface. According to 
the USAF, even if the weapon failed to detonate, gun-type projectiles 
lose lethal velocity within a few feet of the surface. Lastly, if a 
marine mammal enters the exercise area during a live-fire event, 
exercises would cease immediately, and the activity would either remain 
suspended until the area was determined to be clear of marine mammals 
or moved to a new area, where pre-mission surveys would be conducted be 
recommencing live-fire events.
    Comment 4: The MMC states that until data are available that 
demonstrate the effectiveness of electronic detection techniques in 
higher sea states, authorizing incidental taking during operations 
conducted in such conditions is premature. Therefore, the MMC 
recommends that NMFS work with the USAF to design and conduct the 
necessary performance verification testing for electronic detection 
devices under the pertinent sea state conditions.
    Response: For the 2008 IHA, NMFS increased the sea state 
restriction from 3 to 4. The reasoning for increasing the sea state 
limitation was fully explained in the 2008 IHA Notice of Issuance (73 
FR 78318, December 22, 2008) and NMFS' 2008 EA. Readers should refer to 
those documents for the explanation.
    USAF subject matter experts have determined based on in-the-field 
experience, the airborne systems adequately function in a sea state of 
4. Research conducted by Baldacci et al. (2005) indicated a sea state 
of 2 or 3 was pushing their system capabilities. However, Baldacci et 
al. (2005) were looking horizontally along the surface of the water, 
whereas the USAF is looking nearly straight down, thus improving system 
capabilities in higher sea states. Specific system capabilities/
limitations are classified and cannot be publicly provided.
    Sensor Operators are continuously scanning the area for traffic, 
boats, marine mammals, etc. when transiting to and from the water 
exercise ranges. The USAF will instruct the Sensor Operators to begin 
gathering additional data, such as sea state and level of difficulty in 
detecting objects at the different sea states, during those transits 
for comparison purposes, as long as doing so does not interfere with 
mission training activities. Beyond this new data collection effort, 
NMFS is uncertain what the MMC intended, as they did not provide any 
specific details on the types of data that should be collected or 
collection methods.
    Comment 5: The MMC recommends that NMFS review its overall strategy 
for managing risks associated with such testing and training activities 
and consider how its existing strategy might be modified to be both 
more precautionary but also more likely to lead to scientific 
advancement in this field of research.
    Response: Pursuant to section 101(a)(5)(D) of the MMPA, NMFS may 
issue an IHA if it finds that the activity will have a negligible 
impact on the affected species or stock and that such taking will not 
have an unmitigable adverse impact on the affected species or stock for 
subsistence uses (where relevant). Additionally, NMFS must prescribe 
means of effecting the least practicable impact on the affected species 
or stocks and their habitats. In this case, NMFS reviewed and analyzed 
the activity and the mitigation measures proposed by USAF to determine 
whether there would be a negligible impact on the affected species and 
stocks and whether they constitute the means of effecting the least 
practicable impact. NMFS has made both these determinations.
    The USAF is currently using the results of a recent habitat/species 
abundance survey in order to limit exercises in areas during times of 
year when high marine species abundance is anticipated. In 2007, Dr. 
Lance Garrison, NMFS Southeast Fisheries Science Center, conducted a 
marine species habitat modeling survey in the EGTTR as part of the 
Department of Defense Legacy Resource Management Program. In this 
project, the researchers developed habitat models using new aerial 
survey line transect data collected during the winter and summer of 
2007. In combination with remotely sensed habitat parameters (i.e., sea 
surface temperature and chlorophyll), these

[[Page 5048]]

data were used to develop spatial density models for bottlenose 
dolphins and several sea turtle species within continental shelf and 
coastal waters of the eastern GOM. The ``species-environment'' 
relationship describes the environmental preferences and tolerances of 
the target species. This relationship is then projected spatially to 
provide a finer-scale prediction of areas within a region where animal 
density is expected to be highest. Similarly, the relationship can be 
used to predict the density of animals outside of the time period or 
area when survey data are collected. Although there are some 
limitations to the results of Dr. Garrison's study, the data are used 
by training crews at Eglin AFB to help determine the best locations for 
training missions in the EGTTR so that areas with high abundances of 
marine mammals and sea turtles can be avoided. Such scientific studies 
are being used to reduce impacts to marine mammals (and other protected 
species) in the EGTTR.

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 document.
    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.
    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's Eastern Planning Area, an area 
of 70,470 km\2\. Texas A&M University and NMFS conducted the surveys 
from 1996 to 1998. A complete discussion on the abundance and density 
data can be found in the Notice of Proposed IHA (74 FR 53474, October 
19, 2009) and 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 AFB that A-S 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 since that time. That information was provided 
in the Notice of Proposed IHA (74 FR 53474, October 19, 2009) and is 
not repeated here. Table 1 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.

               Table 1. Current NMFS acoustic criteria when addressing harassment from explosives
----------------------------------------------------------------------------------------------------------------
 
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Level B Behavior                                 177 dB re 1 microPa\2\-sec 1/3 Octave SEL (sound energy level)
----------------------------------------------------------------------------------------------------------------
Level B TTS Dual Criterion                                            182 dB re 1 microPa\2\-sec 1/3 Octave SEL
----------------------------------------------------------------------------------------------------------------
Level B TTS Dual Criterion                                                                               23 psi
----------------------------------------------------------------------------------------------------------------
Level A PTS (permanent threshold shift)                                          205 dB re 1 microPa\2\-sec SEL
----------------------------------------------------------------------------------------------------------------
Level A Injury (non-hearing related)                                                                13 psi-msec
----------------------------------------------------------------------------------------------------------------
Mortality                                                                                         30.5 psi-msec
----------------------------------------------------------------------------------------------------------------

    TTS can disrupt behavioral patterns by inhibiting an animal's 
ability to communicate with conspecifics and interpret other 
environmental cues important for predator avoidance and prey capture. 
However, depending on the degree (elevation of threshold in dB), 
duration (i.e., recovery time), and frequency range of TTS, and the 
context in which it is experienced, TTS can have effects on marine 
mammals ranging from discountable to serious. For example, a marine 
mammal may be able to readily compensate for a brief, relatively small 
amount of TTS in a non-critical frequency range that takes place during 
a time when the animal is traveling through the open ocean, where 
ambient noise is lower and there are not as many competing sounds 
present. Alternatively, a larger amount and

[[Page 5049]]

longer duration of TTS sustained during a time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts if it were in the same frequency band as the necessary 
vocalizations and of a severity that it impeded communication.
    The following physiological mechanisms are thought to play a role 
in inducing auditory fatigue: effects to sensory hair cells in the 
inner ear that reduce their sensitivity; modification of the chemical 
environment within the sensory cells; residual muscular activity in the 
middle ear; displacement of certain inner ear membranes; increased 
blood flow; and post-stimulatory reduction in both efferent and sensory 
neural output. Ward (1997) suggested that when these effects result in 
TTS rather than permanent threshold shift (PTS), they are within the 
normal bounds of physiological variability and tolerance and do not 
represent a physical injury. Additionally, Southall et al. (2007) 
indicate that although PTS is a tissue injury, TTS is not, because the 
reduced hearing sensitivity following exposure to intense sound results 
primarily from fatigue, not loss, of cochlear hair cells and supporting 
structures and is reversible. Accordingly, NMFS classifies TTS (when 
resulting from exposure to underwater detonations) as Level B 
Harassment, not Level A Harassment (injury).

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. 
However, the possibility of DPI to marine mammals is considered highly 
unlikely. Therefore, the risk of injury or mortality is low. The Notice 
of Proposed IHA (74 FR 53474, October 19, 2009) contained a complete 
discussion of possible impacts from DPI on marine mammals. Impacts to 
marine mammals from Eglin AFB's activities 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).
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. 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. A full description of anticipated effects on habitat was 
provided in the Notice of Proposed IHA (74 FR 53474, October 19, 2009). 
Based on that information, NMFS has determined that the 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. 
The 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.

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 included in this IHA are the same as those 
required in the 2008-2009 IHA (73 FR 78318, December 22, 2008), which 
are also 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 (see ADDRESSES). The revisions to those three requirements are 
also included in this 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 of Issuance (73 FR 78318, December 
22, 2008) or NMFS' 2008 EA (see ADDRESSES) for the full explanation.

Development of the Training Round (TR)

    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 marine mammal has left the area. Daytime and 
nighttime visual monitoring will be supplemented with infrared (IR) and 
low-light television (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 is required for the initial gun calibration, and, after this 
phase, the guns may be

[[Page 5050]]

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 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.

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 also required in the 2010 IHA. These 
requirements are:
    (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 nighttime 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 A-S gunnery exercise.
    NMFS 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 determined that the 
required 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.

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 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 has included these same measures in the 2010 IHA. 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

[[Page 5051]]

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 A-S 
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 and 
authorized for 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 required to 
be implemented (described earlier in this document), no injury or 
mortality of marine mammals is anticipated as a result of or authorized 
for the A-S gunnery mission activities.
    The Notice of Proposed IHA (74 FR 53474, October 19, 2009) included 
an in-depth discussion of the methodology used by Eglin AFB and NMFS to 
estimate take by harassment incidental to the A-S gunnery exercises and 
the numbers of cetaceans that might be affected by the exercises. A 
summary is provided here.
    DPI 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. 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 required mitigation measures 
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. As shown in the 2002 Final PEA and the Notice of Proposed IHA 
(74 FR 53474, October 19, 2009), 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, DPI from gunnery 
activities may also affect marine mammals in the surface zone. Again, 
DPI are anticipated to affect only marine mammals at or near the ocean 
surface. Accordingly, the density estimates have been adjusted to 
indicate surface animals only being potentially affected. 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.
    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), as well as the Notice of 
Proposed IHA (74 FR 53474, October 19, 2009) and are summarized in this 
document. 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.
    Permanent hearing loss is considered an injury and is termed 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, as well as for Level A harassment, 
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 net explosive weight used, resulted in 
a zone of possible Level B harassment approximately equal to that 
obtained by using a 182 decibel (dB) re 1 microPa2-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

[[Page 5052]]

but that one should use 23 psi. This explanation was provided in the 
Notice of Proposed IHA (74 FR 53474, October 19, 2009).
    Table 1 (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 2 provides the 
estimated ZOI radii for the EGTTR ordnance.

                                  Table 2. Estimated Range for a Zone of Impact (ZOI) Distance for the EGTTR Ordnance.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     Level A Harassment-     Level B Harassment Non-   Level B Harassment Non-   Level B Harassment-Non-
                   Expendable                       Injurious(205 dB) EFD    Injurious (182 dB) EFD    injurious (23 psi) For    injurious (177 dB) EFD
                                                             (m)                   For TTS (m)                 TTS (m)              For Behavior (m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
105 mm FU                                                            0.79                      11.1                       216                      22.1
--------------------------------------------------------------------------------------------------------------------------------------------------------
105-mm TR                                                            0.22                       3.0                        90                       6.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
40-mm HE                                                             0.33                       4.7                       122                       9.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
25-mm HE                                                             0.11                       1.3                        49                       2.6
--------------------------------------------------------------------------------------------------------------------------------------------------------
FU=Full-up; TR=Training Round; HE=High Explosive

    Based on the detailed discussion contained in the Notice of 
Proposed IHA (74 FR 53474, October 19, 2009), Table 3 in this Federal 
Register document provides Eglin AFB's estimates of the annual number 
of marine mammals, by species, potentially taken by Level B harassment, 
by the gunnery mission noise. It should be noted that these estimates 
are derived without consideration of the effectiveness of the required 
mitigation measures (except use of the TR), which are discussed earlier 
in this document. As indicated in Table 3, Eglin AFB and NMFS estimate 
that up to 271 marine mammals may incur Level B (TTS) harassment 
annually. 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 NMFS' estimates, up to 25 marine mammals may experience a behavioral 
response to these exercises during the time frame of an IHA (see Table 
3). 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 
1,000 marine mammals of 16 stocks may incur Level B (harassment) takes 
during the 1-year period of an IHA. NMFS has determined that this 
number will be significantly lower due the to the expected 
effectiveness of the mitigation measures required in the IHA. 
Additionally, mortality resulting from either DPI or the resulting 
sounds generated into the water column from detonations was determined 
to be highly unlikely.

[[Page 5053]]



                                                    Table 3. Yearly Estimated Number of Marine Mammals Affected by the Gunnery Mission Noise
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                               Level A Harassment        Level B Harassment Non-                                      Level B Harassment Non-
                     Species                      Adjusted Density (/km\2\)              For Ear Rupture                   TTS                Injurious 23 psi For TTS               Behavior
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale                                                       0.007                    <0.001                         0.010                           0.4                           0.041
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sperm whale                                                         0.011                    <0.001                         0.016                           0.0                           0.064
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dwarf/pygmy sperm whale                                             0.024                    <0.001                         0.035                           1.5                           0.139
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale                                                0.10                    <0.001                         0.015                           0.6                           0.058
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mesoplodon spp.                                                     0.019                    <0.001                         0.028                           1.2                           0.110
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy killer whale                                                  0.030                    <0.001                         0.044                           1.9                           0.174
------------------------------------------------------------------------------------------------------------------------------------------------------------------
False killer whale                                                  0.026                    <0.001                         0.038                           1.6                           0.151
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Short-finned pilot whale                                            0.027                    <0.001                         0.039                           1.7                           0.157
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Rough-toothed dolphin                                               0.028                    <0.001                         0.041                           1.7                           0.163
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin                                                  0.810                     0.006                         1.177                          50.1                           4.706
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Risso's dolphin                                                     0.113                     0.001                         0.164                           7.0                           0.657
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin                                            0.677                     0.005                         0.984                          41.9                           3.934
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pantropical spotted dolphin                                         1.077                     0.008                         1.565                          66.7                           6.258
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Striped dolphin                                                     0.237                     0.002                         0.344                          14.7                           1.377
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Spinner dolphin                                                     0.915                     0.007                         1.330                          56.6                           5.316
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Clymene dolphin                                                     0.253                     0.002                         0.368                          15.7                           1.470
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unidentified dolphin**                                              0.053                    <0.001                         0.077                           3.3                           0.308
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unidentified whale                                                  0.008                    <0.001                         0.012                           0.5                           0.046
------------------------------------------------------------------------------------------------------------------------------------------------------------------
All marine mammals                                                  4.325                     0.032                          6.29                         271.1                           25.13
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
km\2\ = square kilometers; NA = not applicable
*dB= dB re 1 Pa\2\-s
**Bottlenose dolphin/Atlantic spotted dolphin


[[Page 5054]]

Negligible Impact Determination

    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ''...an 
impact resulting from the specified activity that cannot be