Taking of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Training Operations Conducted Within the Gulf of Mexico Range Complex, 9250-9264 [2011-3629]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 33 (Thursday, February 17, 2011)]
[Rules and Regulations]
[Pages 9250-9264]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-3629]



[[Page 9250]]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 218

RIN 0648-AX86


Taking of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Training Operations Conducted 
Within the Gulf of Mexico Range Complex

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

ACTION: Final rule.

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

SUMMARY: NMFS, upon application from the U.S. Navy (Navy), is issuing 
regulations to govern the unintentional taking of marine mammals 
incidental to activities conducted by the Navy's Atlantic Fleet within 
the Gulf of Mexico (GOMEX) Range Complex for the period of April 2010 
through April 2015. The Navy's activities are considered military 
readiness activities pursuant to the Marine Mammal Protection Act 
(MMPA), as amended by the National Defense Authorization Act for Fiscal 
Year 2004 (NDAA). These regulations, which allow for the issuance of 
``Letters of Authorization'' (LOAs) for the incidental take of marine 
mammals during the described activities and specified timeframes, 
prescribe the permissible methods of taking and other means of 
effecting the least practicable adverse impact on marine mammal species 
and their habitat, as well as requirements pertaining to the monitoring 
and reporting of such taking.

DATES: Effective February 17, 2011 through February 17, 2016.

ADDRESSES: A copy of the Navy's application (which contains a list of 
the references used in this document), NMFS' Record of Decision (ROD), 
and other documents cited herein 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 or by telephone via the contact 
listed here (see FOR FURTHER INFORMATION CONTACT). Additionally, the 
Navy's LOA application may be obtained by visiting the Internet at: 
https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications.

FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289, ext. 137.

SUPPLEMENTARY INFORMATION: 

Availability

    Extensive SUPPLEMENTARY INFORMATION was provided in the proposed 
rule for this activity, which was published in the Federal Register on 
Tuesday, July 14, 2009 (74 FR 33960). This information will not be 
reprinted here in its entirety; rather, all sections from the proposed 
rule will be represented herein and will contain either a summary of 
the material presented in the proposed rule or a note referencing the 
page(s) in the proposed rule where the information may be found. Any 
information that has changed since the proposed rule was published will 
be addressed herein. Additionally, this final rule contains a section 
that responds to the comments received during the public comment 
period.

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (Secretary) to allow, upon request, 
the incidental, but not intentional taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) if certain findings are made and regulations are issued or, if 
the taking is limited to harassment, notice of a proposed authorization 
is provided to the public for review.
    Authorization for incidental takings may be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses, and if 
the permissible methods of taking and requirements pertaining to the 
mitigation, monitoring and reporting of such taking are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``an 
impact resulting from the specified activity that cannot be reasonably 
expected to, and is not reasonably likely to, adversely affect the 
species or stock through effects on annual rates of recruitment or 
survival.''
    With respect to military readiness activities, the MMPA defines 
``harassment'' as ``(i) any act that injures or has the significant 
potential to injure a marine mammal or marine mammal stock in the wild 
[Level A Harassment]; or (ii) any act that disturbs or is likely to 
disturb a marine mammal or marine mammal stock in the wild by causing 
disruption of natural behavioral patterns, including, but not limited 
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to 
a point where such behavioral patterns are abandoned or significantly 
altered [Level B Harassment].''

Summary of Request

    On October 2, 2008, NMFS received an application from the Navy 
requesting an authorization for the take of marine mammal species/
stocks incidental to the proposed training operations within the GOMEX 
Range Complex over the course of 5 years. On April 24, 2009, NMFS 
received additional information and clarification on the Navy's 
proposed GOMEX Range Complex training activities. These training 
activities are classified as military readiness activities. The Navy 
states that these training activities may cause various impacts to 
marine mammal species in the proposed GOMEX Range Complex Study Area. 
The Navy requests an authorization to take 17 species of cetaceans 
annually by Level B harassment, and 1 individual each of pantropical 
spotted dolphin and spinner dolphin by Level A harassment (injury). 
However, due to the implementation of the proposed mitigation and 
monitoring measures, NMFS believes that the actual take would be less 
than estimated by the Navy.

Description of the Specified Activities

    The proposed rule contains a complete description of the Navy's 
specified activities that are covered by these final regulations, and 
for which the associated incidental take of marine mammals will be 
authorized in the related LOAs. The proposed rule describes the nature 
and number of the training activities. These training activities 
consist of surface warfare [(Bombing Exercise (Air-to-Surface) or 
BOMBEX (A-S), and Small Arms Training (explosive hand grenades)] and 
vessel movement to, from and within the GOMEX Range Complex Study Area. 
The narrative description of the action contained in the proposed rule 
(74 FR 33960; July 14, 2009; pages 33961-33962) has not changed, except 
that the event duration for Small Arms Training was corrected to ``1-2 
hours'' from ``1 hour'' in Table 1 of the proposed rule (74 FR 33960; 
July 14, 2009; page 33962). This change was to correct a typographical 
error in the proposed rule. Table 1 summarizes the nature and levels of 
these planned activities.

[[Page 9251]]



                            Table 1--Level of Surface Warfare Training Activities Planned in the GOMEX Range Complex per Year
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                   Potential time of
            Operation                  Platform         System/ordnance    Number of events      Training area            day           Event duration
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bombing Exercise (BOMBEX) (Air-   F/A-18............  MK-83 [1,000-lb     1 event (4 bombs    BOMBEX Hotbox.....  Daytime only......  1 hour.
 to-Surface, At-Sea).                                  High Explosive      in succession).
                                                       (HE) bomb] 415.8
                                                       lbs NEW.
Small Arms Training.............  Maritime            MK3A2 anti-swimmer  6 events* (20 live  UNDET Area E3.....  Day or night......  1-2 hours.
                                   Expeditionary       grenades (8-oz HE   grenades).
                                   Support Group       grenade) 0.5 lb
                                   (Various Small      NEW.
                                   Boats).
--------------------------------------------------------------------------------------------------------------------------------------------------------
*An individual event can include detonation of up to 10 live grenades, but no more than 20 live grenades will be used per year.

Description of Marine Mammals in the Area of the Specified Activities

    Twenty-nine marine mammal species have confirmed or potential 
occurrence in the GOMEX Study Area. These include 28 cetacean species 
and 1 sirenian species (DoN, 2007a), which can be found in Table 2. 
Although it is possible that any of the 29 species of marine mammals 
may occur in the Study Area, only 21 of those species are expected to 
occur regularly in the region. Most cetacean species are in the Study 
Area year-round (e.g., sperm whales and bottlenose dolphins), while a 
few (e.g., fin whales and killer whales) have accidental or transient 
occurrence in the area. The Description of Marine Mammals in the Area 
of the Specified Activities section has not changed from what was in 
the proposed rule (74 FR 33960; July 14, 2009; pages 33962-33964).

     Table 2--Marine Mammal Species Found in the GOMEX Range Complex
------------------------------------------------------------------------
  Family and scientific name       Common name         Federal status
------------------------------------------------------------------------
                              Order Cetacea
------------------------------------------------------------------------
                   Suborder Mysticeti (baleen whales)
------------------------------------------------------------------------
Eubalaena glacialis...........  North Atlantic     Endangered.
                                 right whale.
Megaptera novaeangliae........  Humpback whale...  Endangered.
Balaenoptera acutorostrata....  Minke whale.
B. brydei.....................  Bryde's whale.
B. borealis...................  Sei whale........  Endangered.
B. physalus...................  Fin whale........  Endangered.
B. musculus...................  Blue whale.......  Endangered.
------------------------------------------------------------------------
                  Suborder Odontoceti (toothed whales)
------------------------------------------------------------------------
Physeter macrocephalus........  Sperm whale......  Endangered.
Kogia breviceps...............  Pygmy sperm
                                 whale.
K. sima.......................  Dwarf sperm
                                 whale.
Ziphius cavirostris...........  Cuvier's beaked
                                 whale.
M. europaeus..................  Gervais' beaked
                                 whale.
M. bidens.....................  Sowerby's beaked
                                 whale.
M. densirostris...............  Blainville's
                                 beaked whale.
Steno bredanensis.............  Rough-toothed
                                 dolphin.
Tursiops truncatus............  Bottlenose
                                 dolphin.
Stenella attenuata............  Pantropical
                                 spotted dolphin.
S. frontalis..................  Atlantic spotted
                                 dolphin.
S. longirostris...............  Spinner dolphin.
S. clymene....................  Clymene dolphin.
S. coeruleoalba...............  Striped dolphin.
Lagenodephis hosei............  Fraser's dolphin.
Grampus griseus...............  Risso's dolphin.
Peponocephala electra.........  Melon-headed
                                 whale.
Feresa attenuata..............  Pygmy killer
                                 whale.
Pseudorca crassidens..........  False killer
                                 whale.
Orcinus orca..................  Killer whale.
G. macrorhynchus..............  Short-finned
                                 pilot whale.
------------------------------------------------------------------------
                              Order Sirenia
------------------------------------------------------------------------
Trichechus manatus............  West Indian        Endangered.
                                 manatee.
------------------------------------------------------------------------


[[Page 9252]]

Potential Impacts to Marine Mammal Species

    With respect to the MMPA, NMFS' effects assessment on the 
consequences of the Navy's proposed activities on marine mammals and 
their habitat serves four primary purposes: (1) To prescribe the 
permissible methods of taking (i.e., Level B Harassment (behavioral 
harassment), Level A Harassment (injury), or mortality, including an 
identification of the number and types of take that could occur by 
Level A or B harassment or mortality) and to prescribe other means of 
effecting the least practicable adverse impact on such species or stock 
and its habitat (i.e., mitigation); (2) to determine whether the 
specified activity will have a negligible impact on the affected 
species or stocks of marine mammals (based on the likelihood that the 
activity will adversely affect the species or stock through effects on 
annual rates of recruitment or survival); (3) to determine whether the 
specified activity will have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (however, 
there are no subsistence communities in the GOMEX Range Complex Study 
Area); and (4) to prescribe requirements pertaining to monitoring and 
reporting.
    In the Potential Impacts to Marine Mammal Species section of the 
proposed rule, NMFS included a qualitative discussion of the different 
ways that underwater explosive detonations from BOMBEX and Small Arms 
Training with explosive hand grenades may potentially affect marine 
mammals (some of which NMFS would not classify as harassment). See 74 
FR 33960; July 14, 2009; pages 33964-33973. Marine mammals may 
experience direct physiological effects (such as threshold shift), 
acoustic masking, impaired communications, stress responses, and 
behavioral disturbance. The information contained in the Potential 
Impacts to Marine Mammal Species section regarding BOMBEX and Small 
Arms Training in the proposed rule has not changed.
    On April 20, 2010, explosion and fire on the Mobile Offshore 
Drilling Unit Deepwater Horizon MC252 approximately 50 miles southeast 
of the Mississippi Delta led to the BP oil spill, which is the largest 
oil spill in U.S. history and potentially the second largest in world 
history. The oil wellhead leaked for 85 days and was capped on July 15, 
2010. Impacts of this spill are far reaching, and include 
environmental, economic, and societal consequences. Wildlife and 
ecosystems are threatened primarily due to factors such as petroleum 
toxicity and oxygen depletion in the water. Marine species that live in 
the Gulf and in the marshlands surrounding the Gulf are at risk, 
including marine mammals. As of August 31, 2010, 88 dolphins and 1 
whale have been found stranded, including 4 dolphins that were visibly 
oiled. However, the proposed Navy's GOMEX training exercises are not 
expected to further impact the physical marine ecosystem due to the 
nature of the activities.
    Below, in the Estimated Take of Marine Mammals Section, NMFS 
quantifies the potential effects to marine mammals from underwater 
detonation of explosives. In addition, NMFS relates such effects to the 
MMPA definitions of Level A and Level B Harassment. NMFS has also 
considered the effects of mortality on these species, although 
mortality is neither expected, nor will it be authorized.

Mitigation

    In order to issue an incidental take authorization (ITA) under 
Section 101(a)(5)(A) of the MMPA, NMFS must prescribe regulations 
setting forth the ``permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable adverse 
impact on such species or stock and its habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.'' The NDAA amended the MMPA as it relates to military 
readiness activities and the incidental take authorization process such 
that ``least practicable adverse impact'' shall include consideration 
of personnel safety, practicality of implementation, and impact on the 
effectiveness of the ``military readiness activity.'' The GOMEX Range 
Complex training activities described in the proposed rule are 
considered military readiness activities.
    NMFS reviewed the Navy's proposed GOMEX Range Complex training 
activities and the proposed GOMEX Range Complex mitigation measures 
presented in the Navy's application to determine whether the activities 
and mitigation measures were capable of achieving the least practicable 
adverse effect on marine mammals.
    Any mitigation measure prescribed by NMFS should be known to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals (2), (3), and (4) may contribute to this 
goal).
    (2) A reduction in the numbers of marine mammals (total number or 
number at a biologically important time or location) exposed to 
underwater detonations or other activities expected to result in the 
take of marine mammals (this goal may contribute to (1), above, or to 
reducing harassment takes only).
    (3) A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to underwater detonations or other activities expected to result in the 
take of marine mammals (this goal may contribute to (1), above, or to 
reducing harassment takes only).
    (4) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to underwater 
detonations or other activities expected to result in the take of 
marine mammals (this goal may contribute to (1), above, or to reducing 
the severity of harassment takes only).
    (5) A reduction in adverse effects to marine mammal habitat, paying 
special attention to the food base, activities that block or limit 
passage to or from biologically important areas, permanent destruction 
of habitat, or temporary destruction/disturbance of habitat during a 
biologically important time.
    (6) For monitoring directly related to mitigation--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation (e.g., a buffer zone of a 
5,100-yard radius be established and no bombing exercises would be 
initiated marine mammals are detected within the buffer zone, etc.).
    NMFS reviewed the Navy's proposed mitigation measures, which 
included a careful balancing of the likely benefit of any particular 
measure to the marine mammals with the likely effect of that measure on 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the ``military-readiness activity.''
    The Navy's proposed mitigation measures were described in detail in 
the proposed rule (74 FR 33960; July 14, 2009; pages 33973-33975). The 
Navy's measures address personnel training, lookout and watchstander 
responsibilities, operating procedures for training activities using 
underwater detonations of explosives (Bombing Exercises and Small Arms 
Training), and mitigation related to vessel traffic. No changes have 
been made to the mitigation measures described in the proposed rule.

[[Page 9253]]

Monitoring

    In order to issue an ITA for an activity, Section 101(a)(5)(A) of 
the MMPA states that NMFS must 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 LOAs 
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.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    (1) An increase in the probability of detecting marine mammals, 
both within the safety zone (thus allowing for more effective 
implementation of the mitigation) and in general to generate more data 
to contribute to the effects analyses such as whether marine mammals 
are adversely affected by the proposed Navy training exercises in the 
GOM Range Complex.
    (2) An increase in our understanding of how many marine mammals are 
likely to be exposed to levels of underwater detonations or other 
stimuli that we associate with specific adverse effects, such as 
behavioral harassment, temporary threshold shift of hearing sensitivity 
(TTS), or permanent threshold shift of hearing sensitivity (PTS).
    (3) An increase in our understanding of how marine mammals respond 
(behaviorally or physiologically) to underwater detonations or other 
stimuli expected to result in take and how anticipated adverse effects 
on individuals (in different ways and to varying degrees) may impact 
the population, species, or stock (specifically through effects on 
annual rates of recruitment or survival).
    (4) An increased knowledge of the affected species.
    (5) An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.
    (6) A better understanding and record of the manner in which the 
authorized entity complies with the incidental take authorization.

Monitoring Plan for the GOMEX Range Complex Study Area

    The Navy has provided NMFS with a copy of the draft GOMEX Range 
Complex Monitoring Plan. Additionally, NMFS and the Navy have 
incorporated a suggestion from the public, which recommended the Navy 
hold a workshop in 2011 to discuss the Navy's Monitoring Plans for the 
multiple range complexes and training exercises in which the Navy would 
receive ITAs.
    The Navy must notify NMFS immediately (or as soon as clearance 
procedures allow) if the specified activity is thought to have resulted 
in the mortality or injury of any marine mammals, or in any take of 
marine mammals not identified in this document.
    The Navy must conduct all monitoring and/or research required under 
the Letter of Authorization, if issued.
    With input from NMFS, a summary of the monitoring methods required 
for use during training events in the GOMEX Range Complex are described 
below. These methods include a combination of individual elements that 
are designed to allow a comprehensive assessment.
I. Vessel or Aerial Surveys
    (A) The Navy shall visually survey a minimum of 1 explosive event 
per year. If possible, the event surveyed will be one involving 
multiple detonations. One of the vessel or aerial surveys should 
involve professionally trained marine mammal observers (MMOs).
    (B) When operationally feasible, for specified training events, 
aerial or vessel surveys shall be used 1-2 days prior to, during (if 
reasonably safe), and 1-5 days post detonation.
    (C) Surveys shall include any specified exclusion zone around a 
particular detonation point plus 2,000 yards beyond the border of the 
exclusion zone (i.e., the circumference of the area from the border of 
the exclusion zone extending 2,000 yards outwards). For vessel-based 
surveys a passive acoustic system (hydrophone or towed array) could be 
used to determine if marine mammals are in the area before and/or after 
a detonation event.
    (D) When conducting a particular survey, the survey team shall 
collect:
     Location of sighting;
     Species (if not possible, indicate whale, dolphin or 
pinniped);
     Number of individuals;
     Whether calves were observed;
     Initial detection sensor;
     Length of time observers maintained visual contact with 
marine mammal;
     Wave height;
     Visibility;
     Whether sighting was before, during, or after detonations/
exercise, and how many minutes before or after;
     Distance of marine mammal from actual detonations (or 
target spot if not yet detonated);
     Observed behavior--Watchstanders will report, in plain 
language and without trying to categorize in any way, the observed 
behavior of the animal(s) (such as animal closing to bow ride, 
paralleling course/speed, floating on surface and not swimming etc.), 
including speed and direction;
     Resulting mitigation implementation--Indicate whether 
explosive detonations were delayed, ceased, modified, or not modified 
due to marine mammal presence and for how long; and
     If observation occurs while explosives are detonating in 
the water, indicate munitions type in use at time of marine mammal 
detection (e.g., were the 5-inch guns actually firing when the animals 
were sighted? Did animals enter an area 2 minutes after a huge 
explosion went off?).
II. Passive Acoustic Monitoring
    The Navy is required to conduct passive acoustic monitoring when 
operationally feasible.
    (A) Any time a towed hydrophone array is employed during shipboard 
surveys the towed array shall be deployed during daylight hours for 
each of the days the ship is at sea.
    (B) The towed hydrophone array shall be used to supplement the 
ship-based systematic line-transect surveys for marine mammals 
(particularly for species such as beaked whales that are rarely seen).
III. Marine Mammal Observers on Navy Platforms
    (A) MMOs selected for aerial or vessel surveys shall, to the extent 
practicable, be placed on a Navy platform during the exercises being 
monitored.
    (B) The MMO must possess expertise in species identification of 
regional marine mammal species and experience collecting behavioral 
data.
    (C) MMOs shall not be placed aboard Navy platforms for every Navy 
training event or major exercise. Instead, MMOs should be employed 
during specifically identified opportunities deemed appropriate for 
data collection efforts. The events selected for MMO participation 
shall take into account safety, logistics, and operational concerns.
    (D) MMOs shall observe from the same height above water as the 
lookouts.
    (E) The MMOs shall not be part of the Navy's formal reporting chain 
of command during their data collection efforts; Navy lookouts shall 
continue to serve as the primary reporting means within the Navy chain 
of command for marine mammal sightings. The only exception is that if 
an animal is observed within the shutdown zone that

[[Page 9254]]

has not been observed by the lookout, the MMO shall inform the lookout 
of the sighting, and the lookout shall take the appropriate action 
through the chain of command.
    (F) The MMOs shall collect species identification, behavior, 
direction of travel relative to the Navy platform, and distance first 
observed. All MMO sightings shall be conducted according to a standard 
operating procedure. Information collected by MMOs should be the same 
as those collected by Navy lookout/watchstanders described above.
    The Monitoring Plan for the GOMEX Range Complex has been designed 
as a collection of focused ``studies'' (described fully in the GOMEX 
Monitoring Plan) to gather data that will allow the Navy to address the 
following questions:
    (A) What are the behavioral responses of marine mammals that are 
exposed to explosives?
    (B) Is the Navy's suite of mitigation measures effective at 
avoiding injury and mortality of marine mammals?
    Data gathered in these studies will be collected by qualified, 
professional marine mammal biologists or trained Navy lookouts/
watchstanders that are experts in their field. This monitoring plan has 
been designed to gather data on all species of marine mammals that are 
observed in the GOMEX Range Complex study area.

Monitoring Workshop

    During the public comment period on past proposed rules for Navy 
actions (such as the Hawaii Range Complex (HRC) and Southern California 
Range Complex (SOCAL) proposed rules), NMFS received a recommendation 
that a workshop or panel be convened to solicit input on the monitoring 
plan from researchers, experts, and other interested parties. The GOMEX 
Range Complex proposed rule included an adaptive management component 
and both NMFS and the Navy believe that a workshop would provide a 
means for the Navy and NMFS to consider input from participants in 
determining whether (and if so, how) to modify monitoring techniques to 
more effectively accomplish the goals of monitoring set forth earlier 
in the document. NMFS and the Navy believe that this workshop concept 
is valuable in relation to all of the Range Complexes and major 
training exercise rules and LOAs that NMFS is working on with the Navy 
at this time. Consequently, NMFS has determined that this single 
Monitoring Workshop will be included as a component of all of the rules 
and LOAs that NMFS will be processing for the Navy in the next year or 
so.
    The Navy, with guidance and support from NMFS, will convene a 
Monitoring Workshop, including marine mammal and acoustic experts as 
well as other interested parties, in 2011. The Monitoring Workshop 
participants will review the monitoring results from the previous year 
of monitoring pursuant to the GOMEX Range Complex rule as well as 
monitoring results from other Navy rules and LOAs (e.g., VACAPES, 
AFAST, SOCAL, HRC, and other rules). The Monitoring Workshop 
participants would provide their individual recommendations to the Navy 
and NMFS on the monitoring plan(s) after also considering the current 
science (including Navy research and development) and working within 
the framework of available resources and feasibility of implementation. 
NMFS and the Navy would then analyze the input from the Monitoring 
Workshop participants and determine the best way forward from a 
national perspective. Subsequent to the Monitoring Workshop, 
modifications would be applied to monitoring plans as appropriate.

Integrated Comprehensive Monitoring Program

    In addition to the site-specific Monitoring Plan for the GOMEX 
Range Complex, the Navy completed the Integrated Comprehensive 
Monitoring Program (ICMP) Plan at the end of 2009. The ICMP was 
developed by the Navy, with the Chief of Naval Operations Environmental 
Readiness Division (CNO-N45) having the lead. The program does not 
duplicate the monitoring plans for individual areas (e.g., AFAST, HRC, 
SOCAL, VACAPES); instead it is intended to provide the overarching 
coordination that will support compilation of data from both range-
specific monitoring plans as well as Navy funded research and 
development (R&D) studies. The Navy, through its ICMP will coordinate 
the monitoring programs' progress towards meeting its goals and develop 
a data management plan. The ICMP will be evaluated annually to provide 
a matrix for progress and goals for the following year, and will make 
recommendations on adaptive management for refinement and analysis of 
the monitoring methods.
    The primary objectives of the ICMP are to:
     Monitor and assess the effects of Navy activities on 
protected species;
     Ensure that data collected at multiple locations is 
collected in a manner that allows comparison between and among 
different geographic locations;
     Assess the efficacy and practicality of the monitoring and 
mitigation techniques;
     Add to the overall knowledge-base of marine species and 
the effects of Navy activities on marine species.
    The ICMP will be used both as: (1) A planning tool to focus Navy 
monitoring priorities (pursuant to ESA/MMPA requirements) across Navy 
Range Complexes and Exercises; and (2) an adaptive management tool, 
through the consolidation and analysis of the Navy's monitoring and 
watchstander data, as well as new information from other Navy programs 
(e.g., R&D), and other peer-reviewed newly published information.
    In combination with the 2011 Monitoring Workshop and the adaptive 
management component of the GOMEX Range Complex rule and the other Navy 
rules (e.g. VACAPES Range Complex, Jacksonville Range Complex, etc.), 
the ICMP provides a framework for restructuring the monitoring plans 
and allocating monitoring effort based on the value of particular 
specific monitoring proposals (in terms of the degree to which results 
would likely contribute to stated monitoring goals, as well as the 
likely technical success of the monitoring based on a review of past 
monitoring results) that have been developed through the ICMP 
framework, instead of allocating effort based on maintaining an equal 
(or commensurate to effects) distribution of monitoring effort across 
range complexes.
    The ICMP identified:
     A means by which NMFS and the Navy would jointly consider 
prior years' monitoring results and advancing science to determine if 
modifications are needed in mitigation or monitoring measures to better 
effect the goals laid out in the Mitigation and Monitoring sections of 
the GOMEX Range Complex rule.
     Guidelines for prioritizing monitoring projects.
    If, as a result of the workshop and similar to the example 
described in the paragraph above, the Navy and NMFS decide it is 
appropriate to restructure the monitoring plans for multiple ranges 
such that they are no longer evenly allocated (by rule), but rather 
focused on priority monitoring projects that are not necessarily tied 
to the geographic area addressed in the rule, the ICMP will be modified 
to include a very clear and unclassified record-keeping system that 
will allow NMFS and the public to see how each range complex/project is 
contributing to all of the ongoing monitoring programs (resources, 
effort, money, etc.).

[[Page 9255]]

Adaptive Management

    NMFS has included an adaptive management component in the final 
regulations governing the take of marine mammals incidental to Navy 
training exercises in the GOMEX Range Complex. The use of adaptive 
management will give NMFS the ability to consider new data from 
different sources to determine (in coordination with the Navy) on an 
annual basis if mitigation or monitoring measures should be modified or 
added (or deleted) if new data suggests that such modifications are 
appropriate (or are not appropriate) for subsequent annual LOAs, if 
issued.
    The following are some of the possible sources of applicable data:
     Results from the Navy's monitoring from the previous year 
(either from GOMEX Range Complex or other locations)
     Findings of the Workshop that the Navy will convene in 
2011 to analyze monitoring results to date, review current science, and 
recommend modifications, as appropriate to the monitoring protocols to 
increase monitoring effectiveness
     Compiled results of Navy funded research and development 
(R&D) studies (presented pursuant to the ICMP, which is discussed 
elsewhere in this document)
     Results from specific stranding investigations (either 
from GOMEX Range Complex or other locations)
     Results from general marine mammal and sound research 
(funded by the Navy or otherwise)
     Any verified information which reveals that marine mammals 
may have been taken in a manner, extent or number not authorized by 
these regulations or subsequent Letters of Authorization
    Mitigation measures could be modified or added (or deleted) if new 
data suggests that such modifications would have (or do not have) a 
reasonable likelihood of accomplishing the goals of mitigation laid out 
in this proposed rule and if the measures are practicable. NMFS would 
also coordinate with the Navy to modify or add to (or delete) the 
existing monitoring requirements if the new data suggest that the 
addition of (or deletion of) a particular measure would more 
effectively accomplish the goals of monitoring laid out in this 
proposed rule. The reporting requirements associated with this rule are 
designed to provide NMFS with monitoring data from the previous year to 
allow NMFS to consider the data and issue annual LOAs. NMFS and the 
Navy will meet annually, prior to LOA issuance, to discuss the 
monitoring reports, Navy R&D developments, and current science and 
whether mitigation or monitoring modifications are appropriate.

Reporting Measures

    In order to issue an ITA for an activity, Section 101(a)(5)(A) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. Effective reporting is 
critical to ensure compliance with the terms and conditions of a LOA, 
and to provide NMFS and the Navy with data of the highest quality based 
on the required monitoring. Additional detail has been added to the 
reporting requirements since they were outlined in the proposed rule. 
The updated reporting requirements are all included below. A subset of 
the information provided in the monitoring reports may be classified 
and not releasable to the public.
    NMFS will work with the Navy to develop tables that allow for 
efficient submission of the information required below.

General Notification of Injured or Dead Marine Mammals

    Navy personnel will ensure that NMFS (regional stranding 
coordinator) is notified immediately (or as soon as operational 
security allows) if an injured or dead marine mammal is found during or 
shortly after, and in the vicinity of, any Navy training exercise 
utilizing underwater explosive detonations or other activities. The 
Navy will provide NMFS with species or description of the animal(s), 
the condition of the animal(s) (including carcass condition if the 
animal is dead), location, time of first discovery, observed behaviors 
(if alive), and photo or video (if available).

Annual GOMEX Range Complex Monitoring Plan Report

    The Navy shall submit a report annually on March 1 describing the 
implementation and results (through January 1 of the same year) of the 
GOMEX Range Complex Monitoring Plan, described above. Data collection 
methods will be standardized across range complexes to allow for 
comparison in different geographic locations. Although additional 
information will also be gathered, the MMOs collecting marine mammal 
data pursuant to the GOMEX Range Complex Monitoring Plan shall, at a 
minimum, provide the same marine mammal observation data required in 
the major range complex training exercises section of the Annual GOMEX 
Range Complex Exercise Report referenced below.
    The GOMEX Range Complex Monitoring Plan Report may be provided to 
NMFS within a larger report that includes the required Monitoring Plan 
Reports from multiple Range Complexes.

Annual GOMEX Range Complex Exercise Report

    The Navy is in the process of improving the methods used to track 
explosives used to provide increased granularity. The Navy will provide 
the information described below for all of their explosive exercises. 
Until the Navy is able to report in full the information below, they 
will provide an annual update on the Navy's explosive tracking methods, 
including improvements from the previous year.
    (i) Total annual number of each type of explosive exercise (of 
those identified as part of the ``specified activity'' in this final 
rule) conducted in the GOMEX Range Complex.
    (ii) Total annual expended/detonated rounds (missiles, bombs, etc.) 
for each explosive type.

GOMEX Range Complex 5-yr Comprehensive Report

    The Navy shall submit to NMFS a draft report that analyzes and 
summarizes all of the multi-year marine mammal information gathered 
during the GOMEX Range Complex exercises for which annual reports are 
required (Annual GOMEX Range Complex Exercise Reports and GOMEX Range 
Complex Monitoring Plan Reports). This report will be submitted at the 
end of the fourth year of the rule (March 2014), covering activities 
that have occurred through September 1, 2013.

Comments and Responses

    On July 14, 2009, NMFS published a proposed rule (74 FR 33960) in 
response to the Navy's request to take marine mammals incidental to 
military readiness training in the GOMEX Range Complex Study Area and 
requested comments, information and suggestions concerning the request. 
During the 30-day public comment period, NMFS received comments from 3 
private citizens and from the Marine Mammal Commission (Commission). 
The comments are summarized and sorted into general topic areas and are 
addressed below. Full copies of the comment letters may be accessed at 
https://www.regulations.gov.

MMPA Concerns

    Comment 1: The Commission recommended that NMFS require the

[[Page 9256]]

Navy to conduct an external peer review of its marine mammal density 
estimates, the data upon which those estimates are based, and the 
manner in which those data were used for that purpose.
    Response: As discussed in detail in the proposed rule (74 FR 33960; 
July 14, 2009), marine mammal density estimates were based on the most 
recent data and information on the occurrence, distribution, and 
density of marine mammals. The updated density estimates presented in 
this assessment are derived from the Navy OPAREA Density Estimates 
(NODE) for the GOMEX Operation Area (OPAREA) (DoN, 2007).
    Density estimates for cetaceans were either modeled using available 
line-transect survey data or derived using cetacean abundance estimates 
found in the 2006 NOAA stock assessment reports (SARs) (Waring et al., 
2007), which can be viewed at https://www.nmfs.noaa.gov/pr/sars/species.htm. The abundance estimates in the stock assessment reports 
are from Mullin and Fulling (2004).
    For the model-based approach, density estimates were calculated for 
each species within areas containing survey effort. A relationship 
between these density estimates and the associated environmental 
parameters such as depth, slope, distance from the shelf break, sea 
surface temperature (SST), and chlorophyll a (chl a) concentration was 
formulated using generalized additive models (GAMs). This relationship 
was then used to generate a two-dimensional density surface for the 
region by predicting densities in areas where no survey data exist.
    The analyses for cetaceans were based on sighting data collected 
through shipboard surveys conducted by NMFS Southeast Fisheries Science 
Center (SEFSC) between 1996 and 2004. Species-specific density 
estimates derived through spatial modeling were compared with abundance 
estimates found in the 2006 NOAA SARs to ensure consistency. All 
spatial models and density estimates were reviewed by and coordinated 
with NMFS Science Center technical staff and scientists with the 
University of St. Andrews, Scotland, Centre for Environmental and 
Ecological Modeling (CREEM). Subsequent revisions and draft reports 
were reviewed by these same parties. Therefore, NMFS considers that the 
density estimates, including the data upon which those estimates are 
based and the manner in which the data are collected and used, have 
already gone through an independent review process.

Mitigation Measures

    Comment 2: The Commission recommends that NMFS require the Navy to 
develop and implement a plan to evaluate the effectiveness of 
monitoring and mitigation measures before beginning, or in conjunction 
with, the proposed military readiness training operations.
    Response: NMFS has been working with the Navy throughout the 
rulemaking process to develop a series of mitigation, monitoring, and 
reporting protocols. These mitigation, monitoring and reporting 
measures include, but are not limited to: (1) The use of trained 
shipboard lookouts who will conduct marine mammal monitoring to avoid 
collisions with marine mammals; (2) the use of exclusion zones that 
avoid exposing marine mammals to levels of sound likely to result in 
injury or death of marine mammals; (3) several cautionary measures to 
minimize the likelihood of ship strikes of marine mammals; (4) the use 
of MMOs/lookouts to conduct aerial and vessel-based surveys; and (5) 
annual monitoring reports and comprehensive reports to provide insights 
of impacts to marine mammals.
    NMFS has evaluated the effectiveness of the measures and has 
concluded they will result in the least practicable adverse impact on 
the affected marine mammal species or stocks and their habitat. For 
example, operations will be suspended if trained lookouts and/or MMOs 
detect marine mammals within the exercise's specified exclusion zone in 
order to prevent marine mammal injury or mortality. In addition, prior 
to conducting training activities involving underwater explosive 
detonation, the Navy will be required to monitor the safety zones to 
ensure the areas are clear of marine mammals. Such monitoring will also 
be required during the exercise when operationally feasible. These 
monitoring and mitigation measures are expected to reduce the number of 
marine mammals exposed to underwater explosions.
    Over the course of the 5-year rule, NMFS will evaluate the Navy's 
training activities annually to validate the effectiveness of the 
measures. NMFS will, through the established adaptive management 
process, work with the Navy to determine whether additional mitigation 
and monitoring measures are necessary. In addition, with the 
implementation of the ICMP Plan, and the planned Monitoring Workshop in 
2011, NMFS will work with the Navy to further improve its monitoring 
and mitigation plans for its future activities.
    Comment 3. The Commission recommends that NMFS require the Navy to 
describe the protocol for stranding network personnel to communicate 
with the Navy in the event of a stranding that is possibly associated 
with Navy activities.
    Response: As described in the proposed rule (74 FR 33960; July 14, 
2009), the Navy personnel will ensure that NMFS (regional stranding 
coordinator) is notified immediately (or as soon as operational 
security allows) if an injured or dead marine mammal is found during or 
shortly after, and in the vicinity of, any Navy training exercise 
utilizing underwater explosive detonations. The Navy will provide NMFS 
with species or description of the animal(s), the condition of the 
animal(s) (including carcass condition if the animal is dead), 
location, time of first discovery, observed behaviors (if alive), and 
photo or video (if available). This stranding communication protocol is 
similar to the protocol the Navy has for its Atlantic Fleet Active 
Sonar Training (AFAST).
    Comment 4: The Commission recommends that NMFS require the Navy to 
suspend an activity if a marine mammal is seriously injured or killed 
and the injury or death could be associated with the Navy's activity. 
The injury or death should be investigated to determine the cause, 
assess the full impact of the activity or activities potentially 
implicated (e.g., the total of animals involved), and determine how the 
activity should be modified to avoid future injuries or deaths.
    Response: Though NMFS largely agrees with the principle espoused by 
the Commission, it should be noted that without detailed examination by 
an expert, it is usually not feasible to determine the cause of injury 
or mortality when an injured or dead marine mammal is sighted in the 
field. NMFS has included a requirement in the final rule that if there 
is clear evidence that a marine mammal is injured or killed as a result 
of the Navy's training activities (e.g., instances in which it is clear 
that munitions' explosions caused the injury or death), the Navy shall 
suspend its activities immediately and report such incident to NMFS 
through the Navy's chain-of-command.
    For any other sighting of injured or dead marine mammals in the 
vicinity of any Navy training activities utilizing underwater explosive 
detonations for which the cause of injury or mortality cannot be 
immediately determined, the Navy personnel will ensure that NMFS 
(regional stranding coordinator) is notified immediately (or as soon as

[[Page 9257]]

operational security allows). The Navy will provide NMFS with species 
or description of the animal(s), the condition of the animal(s) 
(including carcass condition if the animal is dead), location, time of 
first discovery, observed behaviors (if alive), and photo or video (if 
available).

Miscellaneous Issues

    Comment 5: Three private citizens expressed general opposition to 
Navy activities and NMFS' issuance of an MMPA authorization because of 
the danger of killing marine life.
    Response: NMFS appreciates the commenters' concern for the marine 
mammals that live in the area of the proposed activities. However, the 
MMPA allows individuals to take marine mammals incidental to specified 
activities if NMFS can make the necessary findings required by law 
(i.e., negligible impact, unmitigable adverse impact on subsistence 
users, etc.). As explained throughout this rulemaking, NMFS has made 
the necessary findings under 16 U.S.C. 1371(a)(5)(A) to support our 
issuance of the final rule.

Estimated Take of Marine Mammals

    With respect to the MMPA, NMFS' effects assessment serves four 
primary purposes: (1) To prescribe the permissible methods of taking 
(i.e., Level B Harassment (behavioral harassment), Level A harassment 
(injury), or mortality, including an identification of the number and 
types of take that could occur by Level A or B harassment or mortality) 
and to prescribe other means of affecting the least practicable adverse 
impact on such species or stock and its habitat (i.e., mitigation); (2) 
to determine whether the specified activity will have a negligible 
impact on the affected species or stocks of marine mammals (based on 
the likelihood that the activity will adversely affect the species or 
stock through effects on annual rates of recruitment or survival); (3) 
to determine whether the specified activity will have an unmitigable 
adverse impact on the availability of the species or stock(s) for 
subsistence uses (however, there are no subsistence communities that 
would be affected in the GOMEX Range Complex Study Area, so this 
determination is inapplicable for this rulemaking); and (4) to 
prescribe requirements pertaining to monitoring and reporting.
    In the Estimated Take of Marine Mammals section of the proposed 
rule, NMFS related the potential effects to marine mammals from 
underwater detonation of explosives to the MMPA regulatory definitions 
of Level A and Level B Harassment and assessed the effects to marine 
mammals that could result from the specific activities that the Navy 
intends to conduct. The subsections of this analysis are discussed in 
the proposed rule (74 FR 33960; July 14, 2009) and have not changed.

Acoustic Take Criteria

    In the Acoustic Take Criteria section of the proposed rule, NMFS 
described the development and application of the acoustic criteria for 
explosive detonations (74 FR 33960; July 14, 2009). No changes have 
been made to the discussion contained in this section of the proposed 
rule.

Take Calculations

    An overview of the Navy's modeling methods to determine the number 
of exposures of MMPA-protected species to sound likely to result in 
mortality, Level A harassment (injury), or Level B harassment is 
provided in the Federal Register notice for the proposed rule (74 FR 
33960; pages 33978-33979). No changes have been made to the modeling 
methods in the section of that proposed rule.
    As noticed in the proposed rule, the Navy's modeling revealed that 
only eight marine mammal species (very few individuals of each) would 
be taken by Level A and Level B harassment. However, the Navy stated in 
its addendum to the LOA application, because of the relatively high 
abundance of several species (Bryde's whales, Atlantic spotted 
dolphins, bottlenose dolphins, Clymene dolphins, false killer whales, 
Fraser's dolphins, killer whales, two species of Kogia sp., melon-
headed whales, pygmy killer whales, Risso's dolphins, rough-toothed 
dolphins, short-finned pilot whales, striped dolphins, and several 
species of beaked whales) in the proposed action area (Waring et al., 
2007) and the fact that some of these species aggregate in relatively 
large groups, the Navy considers that additional takes of these species 
by Level B behavioral harassment are possible. After reviewing the 
Navy's request and consulting the most recent stock assessment reports 
of marine mammals in the proposed action area (Waring et al., 2009), 
NMFS largely agrees with the Navy except that NMFS considers that the 
take of Bryde's and killer whales is unlikely due to their rarity in 
the Study Area. However, NMFS considers that the incidental take by 
Level B harassment of sperm whale is likely due to this species 
abundance in the Gulf of Mexico area. Therefore, NMFS has included 
additional species in our take estimates for the 5-year regulations. 
Revised estimates of potential takes from the proposed GOMEX Range 
Complex training activities are summarized in Table 3.


  Table 3--Summary of Potential Exposures From Explosive Ordnance (per
           Year) for Marine Mammals in the GOMEX Range Complex
------------------------------------------------------------------------
                                                  Level A
    Marine mammal species      Level B (non-   (slight lung    Mortality
                                  injury)         injury)
------------------------------------------------------------------------
Sperm whale.................               5               0           0
Atlantic spotted dolphin....              20               0           0
Beaked whales...............              20               0           0
Bottlenose dolphin..........              30               0           0
Clymene dolphin.............              20               0           0
False killer whale..........              10               0           0
Fraser's dolphin............              20               0           0
Kogia sp....................              20               0           0
Melon-headed whale..........              20               0           0
Pantropical spotted dolphin.              26               1           0
Pygmy killer whale..........              10               0           0
Risso's dolphin.............              30               0           0
Rough-toothed dolphin.......              20               0           0
Short-finned pilot whale....              20               0           0
Spinner dolphin.............              27               1           0

[[Page 9258]]

 
Striped dolphin.............              20               0           0
------------------------------------------------------------------------

Effects on Marine Mammal Habitat

    NMFS' GOMEX Range Complex proposed rule included a section that 
addressed the effects of the Navy's activities on Marine Mammal Habitat 
(74 FR 33960; July 14, 2009; page 33979). NMFS concluded that the 
Navy's activities would have minimal effects on marine mammal habitat. 
No changes have been made to the discussion contained in this section 
of the proposed rule.

Analysis and Negligible Impact Determination

    Pursuant to NMFS' regulations implementing the MMPA, an applicant 
is required to estimate the number of animals that will be ``taken'' by 
the specified activities (i.e., takes by harassment only, or takes by 
harassment, injury, and/or death). This estimate informs the analysis 
that NMFS must perform to determine whether the activity will have a 
``negligible impact'' on the species or stock. Level B (behavioral) 
harassment occurs at the level of the individual(s) and does not assume 
any resulting population-level consequences, though there are known 
avenues through which behavioral disturbance of individuals can result 
in population-level effects. A negligible impact finding is based on 
the lack of likely adverse effects on annual rates of recruitment or 
survival (i.e., population-level effects). An estimate of the number of 
Level B harassment takes alone, is not enough information on which to 
base an impact determination.
    In addition to considering estimates of the number of marine 
mammals that might be ``taken'' through behavioral harassment, NMFS 
must consider other factors, such as the likely nature of any responses 
(their intensity, duration, etc.), the context of any responses 
(critical reproductive time or location, migration, etc.), and the 
number and nature of estimated Level A takes, the number of estimated 
mortalities, and effects on habitat.
    The Navy's specified activities have been described based on best 
estimates of the planned detonation events the Navy would conduct for 
the proposed GOMEX Range Complex training activities. Taking the above 
into account, considering the sections discussed below, and dependent 
upon the implementation of the proposed mitigation measures, NMFS has 
determined that Navy training exercises utilizing underwater explosives 
will have a negligible impact on the affected marine mammal species and 
stocks present in the GOMEX Range Complex Study Area.
    NMFS' analysis of potential behavioral harassment, temporary 
threshold shifts, permanent threshold shifts, injury, and mortality to 
marine mammals as a result of the GOMEX Range Complex training 
activities was provided in the proposed rule (74 FR 33960; July 14, 
2009; pages 33965-33972) and is described in more detail below.

Behavioral Harassment

    The Navy plans a total of 1 BOMBEX (Air-to-Surface) training event 
(each lasting for 1 hour) and 6 Small Arms Training (explosive hand 
grenades) events (each lasting for 1-2 hours) annually. The total 
training exercises using high explosives proposed by the Navy in the 
GOMEX Range Complex amount to approximately 13 hours per year. These 
detonation events are widely dispersed throughout several of the 
designated sites within the GOMEX Range Complex Study Area. The 
probability that detonation events will overlap in time and space with 
marine mammals is low, particularly given the densities of marine 
mammals in the GOMEX Range Complex Study Area and the implementation of 
monitoring and mitigation measures. Moreover, NMFS does not expect 
animals to experience repeated exposures to the same sound source as 
animals will likely move away from the source after being exposed. In 
addition, these isolated exposures, when received at distances where 
the Level B behavioral harassment (i.e., 177 dB re 1 microPa\2\-sec) 
threshold would propogate, are expected to cause brief startle 
reactions or short-term behavioral modification by the animals. These 
brief reactions and behavioral changes are expected to disappear when 
the exposures cease. Therefore, these levels of received impulse noise 
from detonation are not expected to affect annual rates of recruitment 
or survival.

TTS

    NMFS and the Navy have estimated that individuals of some species 
of marine mammals may sustain some level of temporary threshold shift 
(TTS) from underwater detonations. TTS can last from a few minutes to 
days, be of varying degree, and occur across various frequency 
bandwidths. The TTS sustained by an animal is primarily classified by 
three characteristics:
     Frequency--Available data (of mid-frequency hearing 
specialists exposed to mid to high frequency sounds--Southall et al., 
2007) suggest that most TTS occurs in the frequency range of the source 
up to one octave higher than the source (with the maximum TTS at \1/2\ 
octave above).
     Degree of the shift (i.e., how many dB is the sensitivity 
of the hearing reduced by)--generally, both the degree of TTS and the 
duration of TTS will be greater if the marine mammal is exposed to a 
higher level of energy (which would occur when the peak dB level is 
higher or the duration is longer). Since the impulse from detonation is 
extremely brief, an animal would have to approach very close to the 
detonation site to increase the received sound exposure level (SEL). 
The threshold for the onset of TTS for detonations is a dual criteria: 
182 dB re 1 microPa\2\-sec or 23 psi, which might be received at 
distances from 345-2,863 m from the centers of detonation based on the 
types of net explosive weight (NEW) involved to receive the SEL that 
causes TTS compared to similar source level with longer durations (such 
as sonar signals).
     Duration of TTS (Recovery time)--Of all TTS laboratory 
studies, some using continuous exposures of almost an hour in duration 
or up to 217 SEL, almost all recovered within 1 day (or less, often in 
minutes), though in one study (Finneran et al., 2007), recovery took 4 
days.
     Although the degree of TTS depends on the received noise 
levels and exposure time, all studies show that TTS is reversible and 
the animal's sensitivity is expected to recover fully in minutes to 
hours. Therefore, NMFS expects that TTS would not affect annual rates 
of recruitment or survival.

[[Page 9259]]

Acoustic Masking or Communication Impairment

    As discussed above, it is also possible that anthropogenic sound 
could result in masking of marine mammal communication and navigation 
signals. However, masking only occurs during the time of the signal 
(and potential secondary arrivals of indirect rays), versus TTS, which 
occurs continuously for its duration. Impulse sounds from underwater 
detonations are extremely brief and the majority of most animals' 
vocalizations would not be masked. Therefore, masking effects from 
underwater detonations are expected to be minimal and unlikely. If 
masking or communication impairment were to occur briefly, it would be 
in the frequency ranges below 100 Hz, which overlaps with some 
mysticete vocalizations; however, it would likely not mask the entirety 
of any particular vocalization or communication series because of the 
short impulse.

PTS, Injury, or Mortality

    The Navy's model estimated that 1 pantropical spotted dolphin and 1 
spinner dolphin could experience 50-percent tympanic membrane rupture 
or slight lung injury (Level A harassment) as a result of the training 
activities utilizing underwater detonation by BOMBEX in the GOMEX Range 
Complex Study Area. However, these estimates do not take into 
consideration the proposed mitigation and monitoring measures. For 
underwater detonations, the animals have to be within an area between 
certain injury zones of influence (ZOI) to experience Level A 
harassment. Such injury ZOI varies from 0.09 km\2\ to 4.98 km\2\ (or at 
distances between 169 m to 1,259 m from the center of detonation) 
depending on the types of munition used and the season of the action. 
Though it is possible that Navy observers could fail to detect an 
animal at a distance of more than 1 km (an injury ZOI during BOMBEX, 
which is planned to have 1 event annually), all injury ZOIs from small 
arms trainings are smaller than 0.1 km\2\ (178 m in radius) and NMFS 
believes it is unlikely that any marine mammal will be missed by 
lookouts/watchstanders or MMOs. As discussed previously, the Navy plans 
to utilize aerial or vessel surveys to detect marine mammals for 
mitigation implementation and indicated that they are capable of 
effectively monitoring safety zones.
    Based on these assessments, NMFS and the Navy determined that 
approximately 5 Sperm whales, 20 Atlantic spotted dolphins, 20 beaked 
whales, 30 bottlenose dolphins, 20 Clymene dolphins, 10 false killer 
whales, 20 Fraser's dolphins, 20 pygmy or dwarf sperm whales, 20 melon-
headed whales, 26 pantropical spotted dolphins, 10 pygmy killer whales, 
30 Risso's dolphins, 20 rough-toothed dolphins, 27 spinner dolphins, 20 
short-finned pilot whales, and 20 striped dolphins could be affected by 
Level B harassment (TTS and sub-TTS) as a result of the proposed GOMEX 
Range Complex training activities. These numbers represent 
approximately 0.30%, 0.07%, 0.81%, 0.30%, 2.57%, 4.42%, 0.88%, 0.08%, 
3.10%, 1.89%, 0.75%, 2.79%, 1.36%, and 0.60%