[Federal Register Volume 78, Number 107 (Tuesday, June 4, 2013)]
[Notices]
[Pages 33357-33369]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-13119]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XC561
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to Conducting Maritime Strike
Operations by Eglin Air Force Base 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 an Incidental Harassment
Authorization (IHA) to take marine mammals, by harassment, incidental
to Maritime Strike Operations in the Gulf of Mexico (GOM). The USAF's
activities are considered military readiness activities. Pursuant to
the Marine Mammal Protection Act (MMPA), NMFS requests comments on its
proposal to issue an IHA to Eglin AFB to take, by harassment, several
species of marine mammal during the specified activity for a period of
1 year.
DATES: Comments and information must be received no later than July 5,
2013.
ADDRESSES: Comments on the application should be addressed to Michael
Payne, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service, 1315 East-West Highway,
Silver Spring, MD 20910. The mailbox address for providing email
comments is [email protected]. NMFS is not responsible for email
comments sent to addresses other than the one provided here. Comments
sent via email, including all attachments, must not exceed a 10-
megabyte file size.
Instructions: All comments received are a part of the public record
and will generally be posted to http://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.
An electronic copy of the application containing a list of the
references used in this document and Eglin AFB's Draft Environmental
Assessment (DEA) 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: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this
notice may also be viewed, by appointment, during regular business
hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Brian D. Hopper, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct
[[Page 33358]]
the Secretary of Commerce to allow, upon request, the incidental, but
not intentional, taking of small numbers of marine mammals by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified geographical region if certain findings are
made and either regulations are issued or, if the taking is limited to
harassment, a notice of a proposed authorization is provided to the
public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s), will not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant), and if the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such takings
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103
as ``. . . an impact resulting from the specified activity that cannot
be reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process
by which citizens of the U.S. can apply for an authorization to
incidentally take small numbers of marine mammals by harassment.
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of
an application followed by a 30-day public notice and comment period on
any proposed authorizations for the incidental harassment of marine
mammals. Within 45 days of the close of the comment period, NMFS must
either issue or deny the authorization.
The National Defense Authorization Act (NDAA) (Pub. L. 108-136)
removed the ``small numbers'' and ``specified geographical region''
provisions and amended the definition of ``harassment'' as it applies
to a ``military readiness activity'' to read as follows (section
3(18)(B) of the MMPA): (i) Any act that injures or has the significant
potential to injure a marine mammal or marine mammal stock in the wild
[Level A Harassment]; or (ii) Any act that disturbs or is likely to
disturb a marine mammal or marine mammal stock in the wild by causing
disruption of natural behavioral patterns, including, but not limited
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to
a point where such behavioral patterns are abandoned or significantly
altered [Level B Harassment].
Summary of Request
NMFS received an application on December 11, 2012, from Eglin AFB
for the taking, by harassment, of marine mammals incidental to Maritime
Strike Operations within the Eglin Gulf Test and Training Range
(EGTTR). A revised application was submitted on January 22, 2013, which
provided updated marine mammal information. The EGTTR is described as
the airspace over the Gulf of Mexico (GOM) that is controlled by Eglin
AFB. The planned test location in the EGTTR is Warning Area 151 (W-
151), which is located approximately 17 miles offshore from Santa Rosa
Island, specifically sub-area W-151A.
The Maritime Strike 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. However, based on analyses provided in
the USAF's Draft Environmental Assessment (DEA), Eglin's IHA
application, including the required mitigation, and for reasons
discussed later in this document, NMFS does not anticipate that Eglin's
Maritime Strike exercises will result in any serious injury or
mortality to marine mammals. Eglin AFB has requested authorization to
take two cetacean species by Level A and Level B harassment. The
requested species include: Atlantic bottlenose dolphin (Tursiops
truncatus) and Atlantic spotted dolphin (Stenella frontalis).
Description of the Specified Activity
This section describes the Maritime Strike missions that have the
potential to affect marine mammals present within the test area.
Maritime Strike operations, a ``military readiness activity'' as
defined under 16 U.S.C. 703 note, involve detonations above the water,
near the water surface, and under water within the EGTTR. These
missions involve multiple types of live munitions identified in Tables
1 and 2 below. The Maritime Strike operations are described in more
detail in the following paragraphs.
The Maritime Strike program was developed in response to the
increasing threats at sea posed by operations conducted from small
boats. The first phase of the Maritime Strike program focused on
detecting and tracking boats using various sensors, simulated weapons
engagements, and testing with inert munitions. The final phase, and the
subject of this notice, consists of testing the effectiveness of live
munitions on small boat threats. The proposed Maritime Strike
activities would involve the use of multiple types of live munitions in
the EGTTR against small boat targets, at all desired surface and water
depth scenarios (maximum depth of 10 feet below the surface) necessary
to carry out the Tactics Development and Evaluation (TD&E) Program.
Multiple munitions (bombs, missiles, and gunner rounds) and aircraft
would be used to meet the objectives of the Maritime Strike program
(Table 1). Because the tests focus on weapon/target interaction,
particular aircraft are not specified for a given test as long as it
meets the delivery parameters. The munitions would be deployed against
static, towed, and remotely controlled boat targets. Static and
controlled targets consist of stripped boat hulls with plywood
simulated crews and systems. Damaged boats would be recovered for data
collection. Test data collection and operation of remotely controlled
boats would be conducted from an instrumentation barge anchored on-
site, which would also provide a platform for cameras and weapon-
tracking equipment. Target boats would be positioned 300 to 600 feet
from the instrument barge, depending on the munition.
Table 1--Live Munitions and Aircraft
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Aircraft (not associated with
Munitions specific munitions)
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GBU-10 laser-guided Mk-84 bomb.......... F-16C fighter aircraft.
GBU-24 laser-guided Mk-84 bomb.......... F-16C+ fighter aircraft.
GBU-31 Joint Direct Attack Munition, F-15E fighter aircraft.
global positioning system guided Mk-84
bomb.
GBU-12 laser-guided Mk-82 bomb.......... A-10 fighter aircraft.
GBU-38 Joint Direct Attack Munition, B-1B bomber aircraft.
global positioning system guided Mk-82
bomb.
GBU-54 Laser Joint Direct Attack B-52H bomber aircraft.
Munition, laser-guided Mk-82 bomb.
CBU-103/B bomb.......................... MQ-1/9 unmanned aerial
vehicle.
AGM-65E/L/K/G2 Maverick air-to-surface
missile.
[[Page 33359]]
AGM-114 Hellfire air-to-surface missile.
M-117 bomb..............................
PGU-12 high explosive incendiary 30 mm
rounds.
M56/PGU-28 high explosive incendiary
20mm rounds.
------------------------------------------------------------------------
Live testing would include three detonation options: (1) Above the
water surface; (2) at the water surface; and (3) below the water
surface (two depths). The number of each type of munition, height or
depth of detonation, explosive material, and net explosive weight (NEW)
of each munition is provided in Table 2.
Table 2--Maritime Strike Munitions
--------------------------------------------------------------------------------------------------------------------------------------------------------
of
Type of munition Total of live detonations by height/ Warhead--explosive Net explosive weight per
munitions depth material munition
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GBU-10.............................. 1 Water Surface: all..... MK-84--Tritonal........... 945 lbs.
GBU-24.............................. 1 Water Surface: all..... MK-84--Tritonal........... 945 lbs.
GBU-31 (JDAM)....................... 13 Water Surface: 4....... MK-84--Tritonal........... 945 lbs (MK-84).
20 feet AGL: 3.........
5 feet underwater: 3...
10 feet underwater: 3..
GBU-12.............................. 1 Water Surface: all..... MK-82--Tritonal........... 192 lbs.
GBU-38 (JDAM)....................... 13 Water Surface: 4....... MK-82--Tritonal........... 192 lbs (MK-82).
20 feet AGL: 3.........
5 feet underwater: 3...
10 feet underwater: 3..
GBU-54 (LJDAM)...................... 1 Water Surface: all..... MK-82--Tritonal........... 192 lbs (MK-82).
AGM-65E/L/K/G2 (Maverick)........... 2 each Water Surface: all..... WDU-24/B penetrating blast- 86 lbs.
(8 total) fragmentation warhead.
CBU-103............................. 4 Water Surface: all..... 202 Blu-97/B Combined 127 lbs.
Effects Bomblets (0.63
lbs each).
AGM-114 (Hellfire).................. 4 Water Surface: all..... High Explosive Anti-Tank 20 lbs.
(HEAT) tandem anti-armor
metal augmented charge.
M-117............................... 6 20 feet AGL: 3......... 750 lb blast/fragmentation 386 lbs (Tritonal).
Water Surface: 3....... bomb, used the same way
as MK-82--Tritonal.
PGU-12 HEI 30 mm.................... 1,000 Water Surface: all..... 30 x 173 mm caliber with 0.1 lbs.
aluminized RDX explosive.
Designed for GAU-8/A Gun
System.
M56/PGU-28 HEI 20 mm................ 1,500 Water Surface: all..... 20 x 120 mm caliber with 0.02 lbs (Comp A-4 HEI).
aluminized Comp A-4 HEI.
Designed for M61 and M197
Gun System.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maritime Strike missions are scheduled to occur over an approximate
two- to three-week period in June 2013. Missions would occur on
weekdays during daytime hours only, with one or two missions occurring
per day. All activities would take place within the EGTTR. Activities
would occur only in Warning Area W-151, and specifically in sub-area W-
151A. W-151A extends approximately 60 nm offshore and has a surface
area of 2,565 nm\2\ (8,797 km\2\). Water depths range from about 30 to
350 m and include continental shelf and slope zones; however, most of
W-151A occurs over the continental shelf, in water depths less than 250
m. Maritime Strike operations would occur in the shallower, northern
inshore portion of W-151A, in water depth of about 35 m (see Figure 2-1
in Eglin's IHA application for a map of the test area).
To ensure safety, prior to conducting Maritime Strike exercises,
Eglin would conduct a pre-test target area clearance procedure for
people and protected species. Support vessels would be deployed around
a defined safety zone to ensure that commercial and recreational boats
do not accidentally enter the area. Before delivering the ordnance,
mission aircraft would make a dry run over the target area to ensure
that it is clear of commercial and recreational boats (at least two
aircraft would participate in each test). Due to the limited duration
of the flyover and potentially high speed and altitude, pilots would
not be able to survey for marine species. In addition, an E-9A
surveillance aircraft would survey the target area for nonparticipating
vessels and other objects on the water surface. Based on the results
from an acoustic impacts analysis for live ordnance detonations, a
separate disturbance zone around the target would be established for
the protection of marine species. The size of the zone would be based
on the distance to which energy- and pressure-related impacts would
extend for the various type of ordnance listed in Table 2 and would not
necessarily be the same size as the human safety zone. Based on the
acoustic modeling result, the largest possible distance from the target
would be 3,526 m (2.2 miles), which corresponds to the 177 dB Level B
harassment threshold for 945 lb NEW munitions detonated at 10 ft
underwater
[[Page 33360]]
(Table 5). At least two of the support vessels would monitor for marine
mammals around the target area. Maritime Strike missions would not
proceed until the target area is determined to be clear of unauthorized
personnel and protected species.
In addition to vessel-based monitoring, one to three video cameras
would be positioned on an instrumentation barge anchored on-site. The
camera configuration and actual number of cameras used would depend on
the specific test being conducted. The cameras are typically used for
situational awareness of the target area and surrounding area, and
could also be used for monitoring the test site for the presence of
marine species. A marine species observer would be located in the Eglin
control tower, along with mission personnel, to monitor the video feed
before and during test activities.
After each test, floating targets would be inspected to identify
and render safe any unexploded ordnance (UXO), including fuzes or
intact munitions. The Eglin Air Force Explosive Disposal Team would be
on hand for each test. UXO that cannot be removed would be detonated in
place, which could result in the sinking of the target vessel. Once the
area has been cleared for re-entry, test personnel would retrieve
target debris and marine species observers would survey the area for
any evidence of adverse impacts to protected species.
Description of Marine Mammals in the Area of the Specified Activity
There are 28 species of marine mammals documented as occurring in
Federal waters of the northern GOM. However, species with likely
occurrence in the test area, and the subject of Eglin's incidental take
request, are the Atlantic bottlenose dolphin (Tursiops truncatus) and
Atlantic spotted dolphin (Stenella frontalis). These two species are
frequently sighted in the northern GOM over the continental shelf, in a
water depth range that encompasses the Maritime Strike test location
(Garrison et al., 2008; Navy, 2007; Davis et al., 2000). Dwarf sperm
whales (Kogia sima) and pygmy sperm whales (K. breviceps) are
occasionally sighted over the shelf, but are not considered regular
inhabitants (Davis et al., 2000). The remaining cetacean species are
primarily considered to occur at or beyond the shelf break (water depth
of approximately 200 m), and are not included in the proposed take
authorization. Of the 28 marine mammal species or stocks that may occur
in the northern GOM, only the sperm whale is listed as endangered under
the ESA and as depleted under the MMPA. Sperm whale occurrence in the
area of the proposed activity is unlikely because almost all reported
sightings have occurred in water depths greater than 200 m. Occurrence
in the deeper portions of W-151 is possible, although based on reported
sightings locations, density is expected to low. Therefore, Eglin AFB
has not requested and NMFS has not proposed the issuance of take
authorizations for this species. Eglin AFB's MMPA application contains
a detailed discussion on the description, status, distribution,
regional distribution, diving behavior, and acoustics and hearing for
the marine mammals in proposed action area. More detailed information
on these species can be found in Wursig et al. (2000), Eglin's DEA (see
ADDRESSES), and in the NMFS U.S. Atlantic and GOM Stock Assessment
Reports (SARs; Waring et al., 2011). This latter document is available
at: http://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.
Density estimates for bottlenose dolphin and spotted dolphin were
derived from two sources. Bottlenose dolphin density estimates were
derived from a habitat modeling project conducted for portions of the
EGTTR, including the Maritime Strike project area (Garrison, 2008).
NMFS developed habitat models using recent aerial survey line transect
data collected during winter and summer. The surveys covered nearshore
and continental shelf waters (to a maximum depth of 200 meters), with
the majority of effort concentrated in waters from the shoreline to 20
meters depth. Marine species encounter rates during the surveys were
corrected for sighting probability and the probability that animals
were available on the surface to be seen. In combination with remotely
sensed environmental data/habitat parameters (water depth, sea surface
temperature and chlorophyll), these data were used to develop habitat
models for cetaceans within the continental shelf and coastal waters of
the eastern GOM. The technical approach, described as Generalized
Regression and Spatial Prediction, spatially projects the species-
habitat relationship based on distribution of environmental factors,
resulting in predicted densities for un-sampled locations and times.
The spatial density model can therefore be used to predict density in
unobserved areas and at different times of year based upon the monthly
composite SST and chlorophyll datasets derived from satellite data.
Similarly, the spatial density model can be used to predict relative
density for any sub-region within the surveyed area.
Garrison (2008) produced bottlenose dolphin density estimates at
various spatial scales within the EGTTR. At the largest scale, density
data were aggregated into four principal strata categories: North-
Inshore, North-Offshore, South-Inshore, and South-Offshore. Densities
for these strata were provided in the published survey report.
Unpublished densities were also provided for smaller blocks (sub-areas)
corresponding to airspace units and a number of these sub-areas were
combined to form larger zones. Densities in these smaller areas were
provided to Eglin AFB in Excel(copyright) spreadsheets by
the report author.
For both large areas and sub-areas, regions occurring entirely
within waters deeper than 200 meters were excluded from predictions,
and those straddling the 200 meter isobath were clipped to remove deep
water areas. In addition, because of limited survey effort, density
estimates beyond 150 meters water depth are considered invalid. The
environmental conditions encountered during the survey periods
(February and July/August) do not necessarily reflect the range of
conditions potentially encountered throughout the year. In particular,
the transition seasons of spring (April-May) and fall (October-
November) have a very different range of water temperatures.
Accordingly, for predictions outside of the survey period or spatial
range, it is necessary to evaluate the statistical variance in
predicted values when attempting to apply the model. The coefficient of
variation (CV) of the predicted quantity is used to measure the
validity of model predictions. According to Garrison (2008), the best
predictions have CV values of approximately 0.2. When CVs approach 0.7,
and particularly when they exceed 1.0, the resulting model predictions
are extremely uncertain and are considered invalid.
Based upon the preceding discussion, the bottlenose dolphin density
estimate used in this document is the median density corresponding to
sub-area 137 (see Figure 3-1 in Eglin AFB's IHA application). The
planned Maritime Strike test location lies within this sub-area. Within
this block, Garrison (2008) provided densities based upon one year
(2007) and five-year monthly averages for SST and chlorophyll. The 5-
year average is considered preferable. Only densities with a CV rounded
to 0.7 or lower (i.e., 0.64 and below) were
[[Page 33361]]
considered. The CV for June in this particular block is 0.62. Density
estimates for bottlenose dolphin are provided in Table 3.
Atlantic spotted dolphin density was derived from Fulling et al.
(2003), which describes the results of mammal surveys conducted in
association with fall ichthyoplankton surveys from 1998 to 2001. The
surveys were conducted by NMFS personnel from the U.S.-Mexico border to
southern Florida, in water depths of 20 to 200 meters. Using the
software program DISTANCE(copyright), density estimates were
generated for East and West regions, with Mobile Bay as the dividing
point. The East region is used in this document. Densities were
provided for Atlantic spotted dolphins and unidentified T. truncatus/S.
frontalis (among other species). The unidentified T. truncatus/S.
frontalis category is treated as a separate species group with a unique
density. Density estimates from Fulling et al. (2003) were not adjusted
for sighting probability (perception bias) or surface availability
(availability bias) [g(0) = 1] in the original survey report, likely
resulting in underestimation of true density. Perception bias refers to
the failure of observers to detect animals, although they are present
in the survey area and available to be seen. Availability bias refers
to animals that are in the survey area, but are not able to be seen
because they are submerged when observers are present. Perception bias
and availability bias result in the underestimation of abundance and
density numbers (negative bias).
Fulling et al. (2003) did not collect data to correct density for
perception and availability bias. However, in order to address this
negative bias, Eglin AFB has adjusted density estimates based on
information provided in available literature. There are no published
g(0) correction factors for Atlantic spotted dolphins. However, Barlow
(2006) estimated g(0) for numerous marine mammal species near the
Hawaiian Islands, including offshore pantropical spotted dolphins
(Stenella attenuata). Separate estimates for this species were provided
for group sizes of 1 to 20 animals [g(0) = 0.76], and greater than 20
animals [g(0) = 1.00]. Although Fulling et al. (2003) sighted some
spotted dolphin groups of more than 20 individuals, the 0.76 value is
used as a more conservative approach. Barlow (2006) provides the
following equation for calculating density:
[GRAPHIC] [TIFF OMITTED] TN04JN13.000
Where
n = number of animal group sightings on effort
S = mean group size
f(0) = sighting probability density at zero perpendicular distance
(influenced by species detectability and sighting cues such as body
size, blows, and number of animals in a group)
L = transect length completed (km)
g(0) = probability of seeing a group directly on a trackline
(influenced by perception bias and availability bias)
Because (n), (S), and (f0) cannot be directly
incorporated as independent values due to lack of the original
information, we substitute the variable Xspecies which
incorporates all three values, such that Xspecies =
(n)(S)(f0) for a given species. This changes the density
equation to:
[GRAPHIC] [TIFF OMITTED] TN04JN13.001
Using the minimum density estimates provided in Fulling et al.
(2003) for Atlantic spotted dolphins and solving for
XSpottedDolphin:
[GRAPHIC] [TIFF OMITTED] TN04JN13.002
XSpottedDolphin = 328.032.
Placing this value of XSpottedDolphin and the revised
g(0) estimate (0.76) in the original equation results in the following
adjusted density estimate for Atlantic spotted dolphin:
[GRAPHIC] [TIFF OMITTED] TN04JN13.003
DAdjusted = 0.265
Using the same method, adjusted density for the unidentified T.
truncatus/S. frontalis species group is 0.009 animals/km\2\. There are
no variances attached to either of these recalculated density values,
so overall confidence in these values is unknown.
Table 3--Marine Mammal Density Estimates
------------------------------------------------------------------------
Density
Species (animals/km\2\)
------------------------------------------------------------------------
Bottlenose dolphin \1\................................. 0.455
Atlantic spotted dolphin \2\........................... 0.265
Unidentified bottlenose dolphin/Atlantic spotted 0.009
dolphin \2\...........................................
------------------------------------------------------------------------
\1\ Source: Garrison, 2008; adjusted for observer and availability bias
by the author.
\2\ Source: Fulling et al., 2003; adjusted for negative bias based on
information provided by Barlow (2003; 2006)
Potential Effects of the Specified Activity on Marine Mammals
Potential impacts from the detonation of explosives include non-
lethal injury (Level A harassment) and disturbance (Level B
harassment). Takes in the form of mortality are neither anticipated nor
requested. The number of marine mammals potentially impacted by
Maritime Strike operations is based on impulsive noise and pressure
waves generated by ordinance detonation at or near the water surface.
Exposure to energy or pressure resulting from these detonations could
result in injury or harassment of marine mammal species. The number of
Maritime Strike missions generally corresponds to the number of live
ordnance expenditures shown in Table 2. However, the number of bursts
modeled for the CBU-103 cluster bomb is 202, which is the number of
individual bomblets per bomb. Also, the 20 mm and 30 mm gunnery rounds
were modeled as one burst each.
Criteria and thresholds for estimating the exposures from a single
explosive activity on marine mammals were established for the Seawolf
Submarine Shock Test Final Environmental Impact Statement (FEIS)
(``SEAWOLF'') and subsequently used in the USS WINSTON S. CHURCHILL
(DDG 81) Ship Shock FEIS (``CHURCHILL'') (DoN,
[[Page 33362]]
1998 and 2001). We adopted these criteria and thresholds in a final
rule on the unintentional taking of marine animals occurring incidental
to the shock testing which involved large explosives (65 FR 77546;
December 12, 2000). Because no large explosives (greater than 1000 lbs
NEW) would be used by Eglin AFB during the specified activities, a
revised acoustic criterion for small underwater explosions (i.e., 23
pounds per square inch [psi] instead of previous acoustic criteria of
12 psi for peak pressure over all exposures) has been established to
predict onset of TTS.
Thresholds and Criteria for Injurious Physiological Impacts
Single Explosion
For injury, NMFS uses dual criteria, eardrum rupture (i.e.
tympanic-membrane injury) and onset of slight lung injury, to indicate
the onset of injury. The threshold for tympanic-membrane (TM) rupture
corresponds to a 50 percent rate of rupture (i.e., 50 percent of
animals exposed to the level are expected to suffer TM rupture). This
value is stated in terms of an Energy Flux Density Level (EL) value of
1.17 inch pounds per square inch (in-lb/in2), approximately 205 dB re 1
microPa\2\-sec.
The threshold for onset of slight lung injury is calculated for a
small animal (a dolphin calf weighing 26.9 lbs), and is given in terms
of the ``Goertner modified positive impulse,'' indexed to 13 psi-msec
(DoN, 2001). This threshold is conservative since the positive impulse
needed to cause injury is proportional to animal mass, and therefore,
larger animals require a higher impulse to cause the onset of injury.
This analysis assumed the marine species populations were 100 percent
small animals. The criterion with the largest potential impact range
(most conservative), either TM rupture (energy threshold) or onset of
slight lung injury (peak pressure), will be used in the analysis to
determine Level A exposures for single explosive events.
For mortality and serious injury, we use the criterion
corresponding to the onset of extensive lung injury. This is
conservative in that it corresponds to a 1 percent chance of mortal
injury, and yet any animal experiencing onset severe lung injury is
counted as a lethal exposure. For small animals, the threshold is given
in terms of the Goertner modified positive impulse, indexed to 30.5
psi-msec. Since the Goertner approach depends on propagation, source/
animal depths, and animal mass in a complex way, the actual impulse
value corresponding to the 30.5 psi-msec index is a complicated
calculation. To be conservative, the analysis used the mass of a calf
dolphin (at 26.9 lbs) for 100 percent of the populations.
Multiple Explosions
For multiple explosions, the CHURCHILL approach had to be extended
to cover multiple sound events at the same training site. For multiple
exposures, accumulated energy over the entire training time is the
natural extension for energy thresholds since energy accumulates with
each subsequent shot (detonation); this is consistent with the
treatment of multiple arrivals in CHURCHILL. For positive impulse, it
is consistent with the CHURCHILL final rule to use the maximum value
over all impulses received.
Thresholds and Criteria for Non-Injurious Physiological Effects
To determine the onset of TTS (non-injurious harassment)--a slight,
recoverable loss of hearing sensitivity, there are dual criteria: an
energy threshold and a peak pressure threshold. The criterion with the
largest potential impact range (most conservative), either the energy
or peak pressure threshold, will be used in the analysis to determine
Level B TTS exposures. We refer the reader to the following sections
for descriptions of the thresholds for each criterion.
Single Explosion--TTS-Energy Threshold
The TTS energy threshold for explosives is derived from the Space
and Naval Warfare Systems Center (SSC) pure-tone tests for TTS
(Schlundt et al., 2000; Finneran and Schlundt, 2004). The pure-tone
threshold (192 dB as the lowest value) is modified for explosives by
(a) interpreting it as an energy metric, (b) reducing it by 10 dB to
account for the time constant of the mammal ear, and (c) measuring the
energy in 1/3-octave bands, the natural filter band of the ear. The
resulting threshold is 182 dB re 1 microPa\2\-sec in any 1/3-octave
band.
Single Explosion--TTS-Peak Pressure Threshold
The second threshold applies to all species and is stated in terms
of peak pressure at 23 psi (about 225 dB re 1 [mu]Pa). This criterion
was adopted for Precision Strike Weapons (PSW) Testing and Training by
Eglin Air Force Base in the Gulf of Mexico (NMFS, 2005). It is
important to note that for small shots near the surface (such as in
this analysis), the 23-psi peak pressure threshold generally will
produce longer impact ranges than the 182-dB energy metric.
Furthermore, it is not unusual for the TTS impact range for the 23-psi
pressure metric to actually exceed the without-TTS (behavioral change
without onset of TTS) impact range for the 177-dB energy metric.
Thresholds and Criteria for Behavioral Effects
Single Explosion
For a single explosion, to be consistent with CHURCHILL, TTS is the
criterion for Level B harassment. In other words, because behavioral
disturbance for a single explosion is likely to be limited to a short-
lived startle reaction, use of the TTS criterion is considered
sufficient protection and therefore behavioral effects (Level B
behavioral harassment without onset of TTS) are not expected for single
explosions.
Multiple Explosions--Without TTS
For multiple explosions, the CHURCHILL approach had to be extended
to cover multiple sound events at the same training site. For multiple
exposures, accumulated energy over the entire uninterrupted firing time
is the natural extension for energy thresholds since energy accumulates
with each subsequent shot (detonation); this is consistent with the
treatment of multiple arrivals in CHURCHILL. Because multiple
explosions could occur within a discrete time period, a new acoustic
criterion-behavioral disturbance without TTS is used to account for
behavioral effects significant enough to be judged as harassment, but
occurring at lower noise levels than those that may cause TTS.
The threshold is based on test results published in Schlundt et al.
(2000), with derivation following the approach of the CHURCHILL FEIS
for the energy-based TTS threshold. The original Schlundt et al. (2000)
data and the report of Finneran and Schlundt (2004) are the basis for
thresholds for behavioral disturbance without TTS. During this study,
instances of altered behavior sometimes began at lower exposures than
those causing TTS; however, there were many instances when subjects
exhibited no altered behavior at levels above the onset-TTS levels.
Regardless of reactions at higher or lower levels, all instances of
altered behavior were included in the statistical summary. The
behavioral disturbance without TTS threshold for tones is derived from
the SSC tests, and is found to be 5 dB below the threshold for TTS, or
177 dB re 1
[[Page 33363]]
microPa\2\-sec maximum energy flux density level in any 1/3-octave band
at frequencies above 100 Hz for cetaceans.
Summary of Thresholds and Criteria for Impulsive Sounds
The effects, criteria, and thresholds used in the assessment for
impulsive sounds are summarized in Table 4. The criteria for behavioral
effects without physiological effects used in this analysis are based
on use of multiple explosives from live, explosive firing during
Maritime Strike exercises.
Table 4--Current NMFS Acoustic Criteria When Addressing Harassment From Explosives
----------------------------------------------------------------------------------------------------------------
Effect Criteria Metric Threshold Effect
----------------------------------------------------------------------------------------------------------------
Mortality...................... Onset of Extensive Goertner modified indexed to 30.5 Mortality.
Lung Injury. positive impulse. psi-msec
(assumes 100
percent small
animal at 26.9
lbs).
Injurious Physiological........ 50 percent Energy flux density... 1.17 in-lb/in\2\ Level A.
Tympanic Membrane (about 205 dB re
Rupture. 1 microPa\2\-
sec).
Injurious Physiological........ Onset Slight Lung Goertner modified indexed to 13 psi- Level A.
Injury. positive impulse. msec (assumes
100 percent
small animal at
26.9 lbs).
Non-injurious Physiological.... TTS............... Greatest energy flux 182 dB re 1 Level B.
density level in any microPa\2\-sec.
\1/3\-octave band (>
100 Hz for toothed
whales and > 10 Hz
for baleen whales)--
for total energy over
all exposures.
Non-injurious Physiological.... TTS............... Peak pressure over all 23 psi........... Level B.
exposures.
Non-injurious Behavioral....... Multiple Greatest energy flux 177 dB re 1 Level B.
Explosions density level in any microPa\2\-sec.
Without TTS. \1/3\-octave (> 100
Hz for toothed whales
and > 10 Hz for
baleen whales)--for
total energy over all
exposures (multiple
explosions only).
----------------------------------------------------------------------------------------------------------------
Anticipated Effects on Habitat
The primary source of marine mammal habitat impact is noise
resulting from live Maritime Strike missions. However, the noise does
not constitute a long-term physical alteration of the water column or
bottom topography. In addition, the activity is not expected to affect
prey availability, is of limited duration, and is intermittent in time.
Surface vessels associated with the missions are present in limited
duration and are intermittent as well. Therefore, it is not anticipated
that marine mammal utilization of the waters in the project area will
be affected, either temporarily or permanently, as a result of mission
activities.
Other sources that could potentially impact marine mammal habitat
were considered and include the introduction of fuel, debris, ordnance,
and chemical materials into the water column. The potential effects of
each were analyzed in the Draft Environmental Assessment and determined
to be insignificant. The analyses are summarized in the following
paragraphs (for a complete discussion of potential effects, please
refer to section 3.3 in the DEA).
Metals typically used to construct bombs, missiles, and gunnery
rounds include copper, aluminum, steel, and lead, among others.
Aluminum is also present in some explosive materials. These materials
would settle to the seafloor after munitions detonate. Metal ions would
slowly leach into the substrate and the water column, causing elevated
concentrations in a small area around the munitions fragments. Some of
the metals, such as aluminum, occur naturally in the ocean at varying
concentrations and would not necessarily impact the substrate or water
column. Other metals, such as lead, could cause toxicity in microbial
communities in the substrate. However, such effects would be localized
to a very small distance around munitions fragments and would not
significantly affect the overall habitat quality of sediments in the
northeastern GOM. In addition, metal fragments would corrode, degrade,
and become encrusted over time.
Chemical materials include explosive byproducts and also fuel, oil,
and other fluids associated with remotely controlled target boats.
Explosive byproducts would be introduced into the water column through
detonation of live munitions. Explosive materials would include 2,4,6-
trinitrotoluene (TNT) and RDX, among others. Various byproducts are
produced during and immediately after detonation of TNT and RDX. During
the very brief time that a detonation is in progress, intermediate
products may include carbon ions, nitrogen ions, oxygen ions, water,
hydrogen cyanide, carbon monoxide, nitrogen gas, nitrous oxide, cyanic
acid, and carbon dioxide (Becker, 1995). However, reactions quickly
occur between the intermediates, and the final products consist mainly
of water, carbon monoxide, carbon dioxide, and nitrogen gas, although
small amounts of other compounds are typically produced as well.
Chemicals introduced into the water column would be quickly
dispersed by waves, currents, and tidal action, and eventually become
uniformly distributed. A portion of the carbon compounds such as carbon
monoxide and carbon dioxide would likely become integrated into the
carbonate system (alkalinity and pH buffering capacity of seawater).
Some of the nitrogen and carbon compounds, including petroleum
products, would be metabolized or assimilated by phytoplankton and
bacteria. Most of the gas products that do not react with the water or
become assimilated by organisms would be released into the atmosphere.
Due to dilution, mixing, and transformation, none of these chemicals
are expected to have significant impacts on the marine environment.
Explosive material that is not consumed in a detonation could sink
to the substrate and bind to sediments. However, the quantity of such
materials is expected to be inconsequential. Research has shown that if
munitions function properly, nearly full combustion of the explosive
materials will occur, and only extremely small amounts of raw material
will remain. In
[[Page 33364]]
addition, any remaining materials would be naturally degraded. TNT
decomposes when exposed to sunlight (ultraviolet radiation), and is
also degraded by microbial activity (Becker, 1995). Several types of
microorganisms have been shown to metabolize TNT. Similarly, RDX
decomposes by hydrolysis, ultraviolet radiation exposure, and
biodegradation.
Based on this information, the proposed Maritime Strike activities
would not have any impact on the food or feeding success of marine
mammals in the northern GOM. Additionally, no loss or modification of
the habitat used by cetaceans in the GOM is expected. Marine mammals
are anticipated to temporarily vacate the area of live fire events.
However, these events usually do not last more than 90 to 120 min at a
time, and animals are anticipated to return to the activity area during
periods of non-activity. Thus, the proposed activity is not expected to
have any habitat-related effects that could cause significant or long-
term consequences for individual marine mammals or on the food sources
that they utilize.
Proposed Mitigation
In order to issue an incidental take authorization (ITA) under
sections 101(a)(5)(A) and (D) of the MMPA, NMFS must, where applicable,
set forth the permissible methods of taking pursuant to such activity
and other means of effecting the least practicable impact on such
species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of such species or stock for taking for certain
subsistence uses (where relevant). The NDAA of 2004 amended the MMPA as
it relates to military readiness activities and the ITA process such
that ``least practicable impact'' shall include consideration of
personnel safety, practicality of implementation, and impact on the
effectiveness of the ``military readiness activity''. The Maritime
Strike activities described in Eglin AFB's application are considered
military readiness activities.
Visual Mitigation
Areas to be used for Maritime Strike operations would be visually
monitored for marine mammal presence from several platforms before,
during, and after the commencement of the mission. Eglin AFB would
provide experienced protected species survey personnel, vessels, and
equipment as required for vessel-based surveys. The primary observers
would be marine scientists with over 1,000 hours of marine mammal
surveying experience collectively. Additionally, all range clearance
personnel involved with the missions would receive NMFS-approved
training developed by the Eglin Natural Resources Section. The
designated protected species survey vessels would be two 25-ft (7.6 m)
Parker 2520 boats with a fully enclosed pilothouse and tower. These
vessels provide large viewing areas and observers would be stationed
approximately 16-ft (4.9 m) above the water surface. Each vessel will
have two observers and each observer will be equipped with binoculars.
Observers will rotate on a regular basis to prevent eye fatigue as
needed. Additional protected species survey vessels can be made
available if required.
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. The visual mitigation
procedures for Maritime Strike operations are outlined below.
Pre-mission: The purposes of pre-mission monitoring are to: (1)
Evaluate the test site for environmental suitability of the mission;
and (2) verify that the Zone of Influence (ZOI) is free of visually
detectable marine mammals, as well as potential indicators of these
species. The area of the ZOI surveyed would be based on the distance to
the largest Level B harassment threshold for the specific ordnance
involved in a given test. For example, the largest ZOI would be 3,526 m
(2.2 mi), which corresponds to the distance to the Level B threshold
(177 dB) for 945 lb munitions detonated at 3 m (10 ft) underwater. The
smallest ZOI would be 37 m (0.02 mi), which is the distance to the
Level B threshold (23 psi) for 20 mm gunnery rounds. Table 5 provides
the ZOI ranges for all the ordnance types and detonation depths
proposed for Maritime Strike operations. On the morning of the Maritime
Strike mission, the test director and safety officer would confirm that
there are no issues that would preclude mission execution and that
weather is adequate to support mitigation measures.
(A) Two Hours Prior to Mission
Mission-related surface vessels would be on site at least two hours
prior to the mission. Observers on board at least one vessel would
assess the overall suitability of the test site based on environmental
conditions (e.g., sea state) and presence/absence of marine mammals or
marine mammal indicators. This information would be related to the
safety officer.
(B) One and One-half Hours Prior to Mission
Vessel-based surveys and video camera surveillance would begin one
and one-half hours prior to live weapon deployment. Surface vessel
observers would survey the applicable ZOI and relay all marine species
and indicator sightings, including the time of sighting and direction
of travel, if known, to the safety officer. Surveys would continue for
approximately one hour. During this time, mission personnel in the test
area would also observe for marine species as feasible. If marine
mammals or indicators are observed within the applicable ZOI, the test
range would be declared ``fouled,'' which would signify to mission
personnel that conditions are such that a live ordnance drop cannot
occur (e.g., protected species or civilian vessels are in the test
area). If no marine mammals or indicators are observed, the range will
be declared ``green.''
(C) One-half Hour Prior to Mission
At approximately 30 minutes prior to live weapon deployment, marine
species observers would be instructed to leave the test site and remain
outside the safety zone, which on average would be 9.5 miles from the
detonation point, (the actual size would be determined by weapon NEW
and method of delivery) during conduct of the mission. Once the survey
vessels have arrived at the perimeter of the safety zone (approximately
30 minutes after being instructed to leave, depending on actual travel
time) the mission would be allowed to proceed. Monitoring for protected
species would continue from the periphery of the safety zone while the
mission is in progress. The other safety boat crews would also be
instructed to observe for marine mammals. Due to the distance from the
target site, these observations would be considered supplemental and
would not be relied upon as the primary monitoring method. After survey
vessels leave the area, marine species monitoring would continue from
the tower through the video feed received from the high definition
cameras on the instrument barge.
(D) Execution of Mission
Immediately prior to live weapons drop, the test director and
safety officer would communicate to confirm the results of marine
mammal surveys and the appropriateness of proceeding with the mission.
The safety officer would have final authority to proceed with,
postpone, move, or cancel the mission.
[[Page 33365]]
The mission would be postponed or moved if:
(1) Any marine mammal is visually detected within the applicable
ZOI. Postponement would continue until the animal(s) that caused the
postponement is confirmed to be outside of the applicable ZOI due to
the animal swimming out of the range.
(2) Large schools of fish or large flocks of birds feeding at the
surface are observed within the applicable ZOI. Postponement would
continue until these potential indicators are confirmed to be outside
the applicable ZOI.
In the event of a postponement, pre-mission monitoring would
continue as long as weather and daylight hours allow.
Post-mission Monitoring: Post mission monitoring would be designed
to determine the effectiveness of pre-mission visual mitigation by
reporting sightings of any dead or injured marine mammals. If post-
mission surveys determine that an injury or lethal take of a marine
mammal has occurred, the next Maritime Strike mission would be
suspended until the test procedure and the monitoring methods would be
reviewed with NMFS and appropriate changes made. Post-mission
monitoring surveys would be conducted by the same observers that
conducted pre-mission surveys, and would commence as soon as EOD
personnel declare the test area safe. Vessels would move into the
applicable ZOI from outside the safety zone and monitor for at least 30
minutes, concentrating on the area down-current of the test site. The
monitoring team would document any marine mammals that were killed or
injured as a result of the test and immediately contact the local
marine mammal stranding network and NMFS to coordinate recovery and
examination of any dead animals. The species, number, location, and
behavior of any animals observed would be documented and reported to
the Eglin Natural Resources Section.
Multiple offshore Air Force missions have been successfully
executed in the general vicinity of the proposed Maritime Strike test
location (W-151 of the EGTTR). These missions have involved both inert
(no explosives) and live weapons testing, and include the following:
2009 Stand-off Precision Guided Munitions (SOPGM) live
missile tests.
2012 Maritime Strike inert drops.
2013 Longbow live missile test (in-air detonation).
2013 Combat Hammer Maritime WESP missions (inert drops in
the Gulf and strafing in the Choctawhatchee Bay).
During these missions, vessel-based observers surveyed for
protected marine species (marine mammals and sea turtles) and species
indicators. They also provided support to enforce human safety
exclusion zones.
All live and inert missions were conducted in a variety of sea
states and weather conditions that encompass the environmental
conditions likely to be encountered during Maritime Strike activities.
While no marine mammals were sighted within the various take threshold
zones (mortality, Level A and B harassment zones) during any of the
live tests (i.e., SOPGM and Longbow missile), survey personnel judged
that they were able to adequately observe the sea surface and there was
reasonable likelihood that marine mammals would have been detected if
present. There have been no documented marine mammal takes throughout
Eglin's history of activities in the Gulf of Mexico. Therefore, based
on these factors, Eglin AFB and NMFS expect that trained protected
species observers would be able to adequately survey and clear
mortality zones (maximum of 457 m) and effectively communicate any
marine mammal sightings to test directors. Further, we expect that test
directors would be able to act quickly to delay live weapon drops
should protected species be observed.
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, 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.
NMFS proposes to include the following measures in the Maritime
Strike IHA (if issued). They are:
(1) Eglin will track their use of the EGTTR for test firing
missions and protected species observations, through the use of mission
reporting forms.
(2) A summary annual report of marine mammal observations and
Maritime Strike 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
Maritime Strike exercise; (ii) a complete description of the pre-
exercise and post-exercise activities related to mitigating and
monitoring the effects of Maritime Strike exercises on marine mammal
populations; and (iii) results of the Maritime Strike exercise
monitoring, including numbers by species/stock of any marine mammals
noted injured or killed as a result of the missions and number of
marine mammals (by species if possible) that may have been harassed due
to presence within the activity zone.
(3) 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.
(4) Any unauthorized takes of marine mammals (i.e., injury or
mortality) must be immediately reported to NMFS and to the respective
stranding network representative.
[[Page 33366]]
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].
Takes by Level A and B harassment are anticipated as a result of
the Maritime Strike mission activities. The exercises are expected to
only affect animals at or very near the surface of the water. Cetaceans
in the vicinity of the exercises may incur temporary changes in
behavior, and/or temporary changes in their hearing thresholds. Based
on the proposed mitigation and monitoring measures described earlier in
this document, no serious injury or mortality of marine mammals is
anticipated as a result of Maritime Strike activities, and no takes by
serious injury or mortality are proposed to be authorized.
Estimating the impacts to marine mammals from underwater
detonations is difficult due to complexities of the physics of
explosive sound under water and the limited understanding with respect
to hearing in marine mammals. Assessments of impacts from Maritime
Strike exercises use, and improve 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 Maritime Strike
exercises include: (1) Mortality, as determined by exposure to a
certain level of positive impulse pressure (expressed as pounds per
square inch per millisecond or psi-msec); (2) injury, both hearing-
related and non-hearing related; and (3) harassment, as determined by a
temporary loss of some hearing ability and behavioral reactions. Due to
the mitigation measures proposed by NMFS for implementation, mortality
resulting from the resulting sounds generated into the water column
from detonations was determined to be highly unlikely and was not
considered further by Eglin AFB or NMFS.
Permanent hearing loss is considered an injury and is termed
permanent threshold shift (PTS). NMFS, therefore, categorizes PTS as
Level A harassment. Temporary loss of hearing ability is termed TTS,
meaning a temporary reduction of hearing sensitivity which abates
following noise exposure. TTS is considered non-injurious and is
categorized as Level B harassment. NMFS recognizes dual criteria for
TTS, one based on peak pressure and one based on the greatest \1/3\
octave sound exposure level (SEL) or energy flux density level (EFDL),
with the more conservative (i.e., larger) of the two criteria being
selected for impacts analysis (note: SEL and EFDL are used
interchangeably, but with increasing scientific preference for SEL).
The peak pressure metric used to predict TTS is 23 pounds per square
inch (psi).
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
the ambient noise environment in which the experiments took place.
Sound levels were progressively increased until behavioral alterations
were noted (at which point the onset of TTS was presumed). It was found
that decreasing the sound intensity by 4 to 6 dB greatly decreased the
occurrence of anomalous behaviors. The lowest sound pressure levels,
over all frequencies, at which altered behaviors were observed, ranged
from 178 to 193 dB re 1 [micro]Pa for the bottlenose dolphins and from
180 to 196 dB re 1 [micro]Pa for the beluga whales. Thus, it is
reasonable to consider that sub-TTS (behavioral) effects occur at
approximately 6 dB below the TTS-inducing sound level, or at
approximately 177 dB in the greatest \1/3\ octave band EFDL/SEL.
Table 4 (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).
The following three factors were used to estimate the potential
noise effects on marine mammals from Maritime Strike operations: (1)
The zone of influence, which is the distance from the explosion to
which a particular energy or pressure threshold extends; (2) the
density of animals potentially occurring within the zone of influence;
and (3) the number of events.
The zone of influence is defined as the area or volume of ocean in
which marine mammals could potentially be exposed to various noise
thresholds associated with exploding ordnance. Table 5 provides the
estimated ZOI radii for the Maritime Strike 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 5--Estimated Range for a Zone of Impact (ZOI) Distance for the Maritime Strike Ordnance
[In meters]
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mortality Level A Harassment Level B Harassment
-----------------------------------------------------------------------------
Munition Height/Depth of detonation 30.5 psi-
msec 205 dB EFD* 13 psi-msec 182 dB EFD* 23 psi 177 dB EFD*
--------------------------------------------------------------------------------------------------------------------------------------------------------
GBU-10..................................... Water Surface................ 202 275 362 1023 1280 1361
GBU-24..................................... Water Surface................ 202 275 362 1023 1280 1361
GBU-31 (JDAM).............................. Water Surface................ 202 275 362 1023 1280 1361
20 feet AGL.................. 0 0 0 0 0 0
[[Page 33367]]
5 feet underwater............ 385 468 700 2084 1281 2775
10 feet underwater........... 457 591 836 2428 1280 3526
GBU-12..................................... Water Surface................ 114 161 243 744 752 1020
GBU-38 (JDAM).............................. Water Surface................ 114 161 243 744 752 1020
20 feet AGL.................. 0 0 0 0 0 0
5 feet underwater............ 239 280 445 1411 752 2070
10 feet underwater........... 279 345 532 1545 752 2336
GBU-54 (LJDAM)............................. Water Surface................ 114 161 243 744 752 1020
AGM-65E/L/K/G2 (Maverick).................. Water Surface................ 84 124 187 618 575 846
CBU-103.................................... Water Surface................ 9 231 21 947 111 1335
AGM-114 (Hellfire)......................... Water Surface................ 46 70 105 425 353 618
M-117...................................... 20 feet AGL.................. 0 0 0 0 0 0
Water Surface................ 147 203 293 847 950 1125
PGU-13 HEI 30 mm........................... Water Surface................ 0 6 7 31 60 55
M56/PGU-28 HEI 20 mm....................... Water Surface................ 0 0 0 16 37 27
--------------------------------------------------------------------------------------------------------------------------------------------------------
* In greatest \1/3\ octave band above 10 Hz or 100 Hz.
Density estimates for marine mammals occurring in the EGTTR are
provided in Table 3. As discussed above, densities were derived from
the results of published documents authored by NMFS personnel. Density
is nearly always reported for an area (e.g., animals per square
kilometer). Analyses of survey results may include correction factors
for negative bias, such as the Garrison (2008) report for bottlenose
dolphins. Even though Fulling et al. (2003) did not provide a
correction for Atlantic spotted dolphins or unidentified bottlenose/
spotted dolphins, Eglin AFB adjusted those densities based on
information provided in other published literature (Barlow 2003; 2006).
Although the study area appears to represent only the surface of the
water (two-dimensional), density actually implicitly includes animals
anywhere within the water column under that surface area. Density
estimates usually assume that animals are uniformly distributed within
the prescribed area, even though this is likely rarely true. Marine
mammals are often clumped in areas of greater importance, for example,
in areas of high productivity, lower predation, safe calving, etc.
Density can occasionally be calculated for smaller areas, but usually
there are insufficient data to calculate density for such areas.
Therefore, assuming an even distribution within the prescribed area is
the typical approach.
In addition, assuming that marine mammals are distributed evenly
within the water column does not accurately reflect behavior. Databases
of behavioral and physiological parameters obtained through tagging and
other technologies have demonstrated that marine animals use the water
column in various ways. Some species conduct regular deep dives while
others engage in much shallower dives, regardless of bottom depth.
Assuming that all species are evenly distributed from surface to bottom
is almost never appropriate and can present a distorted view of marine
mammal distribution in any region. Therefore, a depth distribution
adjustment is applied to marine mammal densities in this document
(Table 6). By combining marine mammal density with depth distribution
information, a three-dimensional density estimate is possible. These
estimates allow more accurate modeling of potential marine mammal
exposures from specific noise sources.
Table 6--Depth Distribution of Marine Mammals in the Maritime Strike Test Area
----------------------------------------------------------------------------------------------------------------
Species Depth distribution Reference
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin.................... Daytime: 96% at <50 m, 4% at Klatsky et al. (2007).
>50 m; Nightime: 51% at <50
m, 8% at 50-100 m, 19% at 101-
250 m, 13% at 251-450 m, and
9% at >450 m.
Atlantic spotted dolphin.............. 76% at <10 m, 20% at 10-20 m, Davis et al. (1996).
and 4% at 21-60 m.
----------------------------------------------------------------------------------------------------------------
As mentioned previously, the number of Maritime Strike activities
generally corresponds to the number of live ordnance expenditures, as
shown in Table 2. However, the number of bursts modeled for the CBU-103
cluster bomb is 202, which is the number of individual bomblets per
bomb. Also, the 20 mm and 30 mm gunnery rounds were modeled as one
burst each.
Table 7 indicates the modeled potential for lethality, injury, and
non-injurious harassment (including behavioral harassment) to marine
mammals in the absence of mitigation measures. The numbers represent
total impacts for all detonations combined. Mortality was calculated as
approximately one-half an animal for bottlenose dolphins and about 0.1
animals for spotted dolphins. It is expected that, with implementation
of the management practices described below, potential impacts would be
mitigated to the point that there would be no mortality takes. Based on
the low mortality exposure estimates calculated
[[Page 33368]]
by the acoustic model combined with the implementation of mitigation
measures, zero marine mammals are expected to be affected by pressure
levels associated with mortality. Therefore, Eglin AFB has requested an
IHA, as opposed to an LOA.
Table 7--Modeled Number of Marine Mammals Potentially Affected by Maritime Strike Missions
----------------------------------------------------------------------------------------------------------------
Level B Level B
Species Mortality Level A Harassment Harassment
Harassment (TTS) (Behavioral)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin.............................. 0.524 2.008 30.187 61.069
Atlantic spotted dolphin........................ 0.145 1.050 16.565 31.345
Unidentified bottlenose dolphin/Atlantic spotted 0.010 0.040 0.597 1.208
dolphin........................................
---------------------------------------------------------------
TOTAL....................................... 0.679 3.098 47.349 93.622
----------------------------------------------------------------------------------------------------------------
Table 8 provides Eglin AFB's the annual number of marine mammals,
by species, potentially taken by Level A harassment and Level B
harassment, by Maritime Strike operations. It should be noted that
these estimates are derived without consideration of the effectiveness
of Eglin AFB's proposed mitigation measures. As indicated in Table 8,
Eglin AFB and NMFS estimate that approximately three marine mammals
could potentially be exposed to injurious Level A harassment noise
levels (205 dB re 1 [mu]Pa\2\-s or higher).
Table 8--Number of Marine Mammals Takes
----------------------------------------------------------------------------------------------------------------
Level B Level B
Species Level A Harassment Harassment
Harassment (TTS) (Behavioral)
----------------------------------------------------------------------------------------------------------------
Bottlenose dolphin.............................................. 2 30 61
Atlantic spotted dolphin........................................ 1 16 32
Unidentified bottlenose dolphin/Atlantic spotted dolphin........ 0 1 1
-----------------------------------------------
TOTAL....................................................... 3 47 93
----------------------------------------------------------------------------------------------------------------
Approximately 47 marine mammals would be exposed annually to non-
injurious (TTS) Level B harassment associated with the 182 dB re 1
[mu]Pa\2\-s threshold. TTS results from fatigue or damage to hair cells
or supporting structures and may cause disruption in the processing of
acoustic cues; however, hearing sensitivity is recovered within a
relatively short time. Based on Eglin AFB and NMFS' estimates, up to 94
marine mammals may experience a behavioral response to these exercises
associated with the 177 dB re 1 [mu]Pa\2\-s threshold (see Table 8).
NMFS has preliminarily determined that this number will be
significantly lower due to the expected effectiveness of the mitigation
measures proposed for inclusion in the IHA (if issued).
Negligible Impact and Preliminary Determinations
NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . .
an impact resulting from the specified activity that cannot be
reasonably expected to, and is not reasonably likely to, adversely
affect the species or stock through effects on annual rates of
recruitment or survival.'' In making a negligible impact determination,
NMFS considers a variety of factors, including but not limited to: (1)
The number of anticipated mortalities; (2) the number and nature of
anticipated injuries; (3) the number, nature, and intensity, and
duration of harassment; and (4) the context in which the takes occur.
The takes from Level B harassment will be due to potential
behavioral disturbance and TTS. The takes from Level A harassment will
be due to potential tympanic-membrane (TM) rupture. Activities would
only occur over a timeframe of two to three weeks in June 2013, with
one or two missions occurring per day. It is possible that some
individuals may be taken more than once if those individuals are
located in the exercise area on two different days when exercises are
occurring. However, multiple exposures are not anticipated to have
effects beyond Level A and Level B harassment.
While animals may be impacted in the immediate vicinity of the
activity, because of the small ZOIs (compared to the vast size of the
GOM ecosystem where these species live) and the short duration of the
Maritime Strike operations, NMFS has preliminarily determined that
there will not be a substantial impact on marine mammals or on the
normal functioning of the nearshore or offshore GOM ecosystems. The
proposed activity is not expected to impact rates of recruitment or
survival of marine mammals since neither mortality (which would remove
individuals from the population) nor serious injury are anticipated to
occur. In addition, the proposed activity would not occur in areas
(and/or times) of significance for the marine mammal populations
potentially affected by the exercises (e.g., feeding or resting areas,
reproductive areas), and the activities would only occur in a small
part of their overall range, so the impact of any potential temporary
displacement would be negligible and animals would be expected to
return to the area after the cessations of activities. Although the
proposed activity could result in Level A (TM rupture) and Level B
(behavioral disturbance and TTS) harassment of marine mammals, the
level of harassment is not anticipated to impact rates of recruitment
or survival of marine mammals because the number of exposed animals is
expected to be low due to the short term and site specific nature of
the activity, and the type of effect would not be detrimental to rates
of recruitment and survival.
Additionally, the mitigation and monitoring measures proposed to be
implemented (described earlier in this document) are expected to
further minimize the potential for harassment.
[[Page 33369]]
The protected species surveys would require Eglin AFB to search the
area for marine mammals, and if any are found in the live fire area,
then the exercise would be suspended until the animal(s) has left the
area or relocated. Moreover, marine species observers located in the
Eglin control tower would monitor the high-definition video feed from
cameras located on the instrument barge anchored on-site for the
presence of protected species. Furthermore, Maritime Strike missions
would be delayed or rescheduled if the sea state is greater than a 4 on
the Beaufort Scale at the time of the test. In addition, Maritime
Strike missions would occur no earlier than two hours after sunrise and
no later than two hours prior to sunset to ensure adequate daylight for
pre- and post-mission monitoring.
Based on the analysis contained herein of the likely effects of the
specified activity on marine mammals and their habitat, and taking into
consideration the implementation of the mitigation and monitoring
measures, NMFS preliminarily finds that Eglin AFB's Maritime Strike
operations will result in the incidental take of marine mammals, by
Level A and Level B harassment only, and that the taking from the
Maritime Strike exercises will have a negligible impact on the affected
species or stocks.
Impact on Availability of Affected Species or Stock for Taking for
Subsistence Uses
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, NMFS has preliminarily determined that the
total taking of affected species or stocks would not have an
unmitigable adverse impact on the availability of such species or
stocks for taking for subsistence purposes.
Endangered Species Act (ESA)
Eglin AFB initiated consultation with the Southeast Region, NMFS,
under section 7 of the ESA regarding the effects of this action on ESA-
listed species and critical habitat under the jurisdiction of NMFS. The
consultation will be completed and a biological opinion issued prior to
any final determinations on the IHA. Due to the location of the
activity, no ESA-listed marine mammal species are likely to be
affected; therefore, NMFS has preliminarily determined that this
proposed IHA would have no effect on ESA-listed species. However, prior
to issuance of this IHA, NMFS will make a final determination whether
additional consultation is necessary.
National Environmental Policy Act (NEPA)
Eglin AFB released a Draft Environmental Assessment (EA) on the
Maritime Strike Operations. NMFS has made this EA available on the
permits Web page. Eglin AFB will issue a Final EA and a Finding of No
Significant Impact (FONSI) on the Maritime Strike Operations prior to
NMFS' final determination on the IHA.
In accordance with NOAA Administrative Order 216-6 (Environmental
Review Procedures for Implementing the National Environmental Policy
Act, May 20, 1999), NMFS will review the information contained in Eglin
AFB's EA and determine whether the EA accurately and completely
describes the preferred action alternative, a reasonable range of
alternatives, and the potential impacts on marine mammals, endangered
species, and other marine life that could be impacted by the preferred
and non-preferred alternatives. Based on this review and analysis, NMFS
may adopt Eglin AFB's PEA under 40 CFR 1506.3, and issue its own FONSI
statement on issuance of an annual authorization under section
101(a)(5) of the MMPA.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
authorize the take of two species of marine mammals incidental to Eglin
AFB's Maritime Strike operations in the GOM provided the previously
mentioned mitigation, monitoring, and reporting requirements are
incorporated.
Dated: May 29, 2013.
Helen M. Golde,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2013-13119 Filed 6-3-13; 8:45 am]
BILLING CODE 3510-22-P