[Federal Register Volume 75, Number 201 (Tuesday, October 19, 2010)]
[Notices]
[Pages 64276-64295]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-26286]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XZ14


Takes of Marine Mammals Incidental to Specified Activities; Navy 
Training Conducted at the Silver Strand Training Complex, San Diego Bay

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 has received an application from the U.S. Navy (Navy) for 
an Incidental Harassment Authorization (IHA) to take marine mammals, by 
harassment, incidental to conducting training exercises at the Silver 
Strand Training Complex (SSTC)

[[Page 64277]]

in the vicinity of San Diego Bay, California. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to the Navy to incidentally harass, by Level B 
Harassment only, four species of marine mammals during the specified 
activity.

DATES: Comments and information must be received no later than November 
18, 2010.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Permits, Conservation and Education Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing e-mail comments is [email protected]. NMFS is not 
responsible for e-mail comments sent to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to 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.
    A copy of the application containing a list of the references used 
in this document 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: Shane Guan, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 137.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce (Secretary) 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) 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 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 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.''
    The National Defense Authorization Act of 2004 (NDAA) (Pub. L. 108-
136) removed the ``small numbers'' and ``specified geographical 
region'' limitations 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].
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States 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.

Summary of Request

    NMFS received an application on March 3, 2010, from the Navy for 
the taking, by harassment, of marine mammals incidental to conducting 
training exercises at the Navy's Silver Strand Training Complex (SSTC) 
in the vicinity of San Diego Bay, California, starting late November 
2010. After addressing comments from NMFS, the Navy modified its 
application and submitted a revised application on September 13, 2010. 
The September 13, 2010, application is the one available for public 
comment (see ADDRESSES) and considered by NMFS for this proposed IHA.

Description of the Specific Activity

    The Navy has been training and operating in the SSTC for over 60 
years. The land, air, and sea spaces of the SSTC have provided, and 
continue to provide, a safe and realistic training environment for 
naval forces charged with defense of the Nation. The SSTC, Figure 1-1 
of the Navy's IHA application, is located south of the City of 
Coronado, California and north of the City of Imperial Beach, 
California. It is composed of ocean and bay training lanes, adjacent 
beach training areas, ocean anchorages, and inland training areas. To 
facilitate range management and scheduling, SSTC is divided into 
numerous training sub-areas (Figure 1-1 of the Navy's IHA application). 
In-water training sub-areas include: The ocean side of the SSTC divided 
into two non-contiguous areas, SSTC-NORTH (Boat Lanes 1-10) and SSTC-
SOUTH (Boat Lanes 11-14); SSTC-NORTH also includes south San Diego Bay 
in-water training areas, designated Alpha through Hotel and the Lilly 
Ann Drop Zone.
    The Navy's mission is to maintain, train, and equip combat-ready 
naval forces capable of winning wars, deterring aggression, and 
maintaining freedom of the seas. Title 10, U.S. Code Section 5062 
directs the Chief of Naval Operations to train all naval forces for 
combat. The Chief of Naval Operations meets that direction, in part, by 
conducting littoral training exercises and ensuring naval forces have 
access to ranges where they can develop and maintain skills for wartime 
missions. The Navy is proposing the following at SSTC: Continue current 
training, increase training tempo and types of training, conduct 
existing routine training at additional locations within SSTC 
established training areas, construct a demolition pit on inland 
training areas, and increase access availability of existing beach and 
inland training areas.
    The Navy has conducted a review of its continuing and proposed 
training conducted at SSTC to determine whether there is a potential 
for harassment of marine mammals. The following discussion describes 
the underwater detonation training and pile driving conducted at SSTC. 
Other training events conducted at SSTC, which are not anticipated to 
rise to the level of harassment to marine mammals

[[Page 64278]]

as defined under the MMPA, are more completely described in the SSTC 
Draft Environmental Impact Statement.

Underwater Detonations

    Underwater detonations are conducted by Explosive Ordnance Disposal 
(EOD) units, Naval Special Warfare (NSW) units, MH-60S Mine 
Countermeasure helicopter squadrons, and Mobile Diving and Salvage 
units at the SSTC. The training provides Navy personnel with hands-on 
experience with the design, deployment, and detonation of underwater 
clearance devices of the general type and size that they are required 
to understand and utilize in combat. EOD groups conduct most of the 
underwater detonation training at SSTC as part of their training in the 
detection, avoidance, and neutralization of mines to protect Navy ships 
and submarines, and offensive mine laying in naval operations.
    For safety reasons, underwater detonation training only occurs 
during daylight and can only be conducted in sea-states of up to 
Beaufort 3 (presence of large wavelets, crests beginning to break, 
presence of glassy foam, and/or perhaps scattered whitecaps). Table 1 
describes the types of underwater detonation training events conducted 
within the SSTC.

  Table 1--Detailed Descriptions of SSTC Underwater Detonation Training
                                 Events
------------------------------------------------------------------------
   Training duration/event                    Description
------------------------------------------------------------------------
Shock Wave Action Generator    SWAG is a tool used by Explosive Ordnance
 (SWAG).                        Disposal (EOD) to disarm enemy limpet
1 day........................   mines which have been attached to the
                                hull of a ship. The SWAG is composed of
                                a cylindrical steel tube, 3 inches long
                                and 1 inch wide, containing
                                approximately 0.033 lbs of explosives.
                                The single explosive charge is highly
                                focused. For SWAG training, a metal
                                sheet containing an inert mine is
                                lowered from the side of a small vessel,
                                or small boat. Divers place a single
                                SWAG on the mine that is located mid-
                                water column, within water depths of 10-
                                20 feet. A bag is placed over the mine
                                to catch falling debris.
Mine Counter Measure.........  Events are performed from a small craft
1 day........................   to locate and identify suspected
                                ordnance either at mid-column or on the
                                sea floor at a water depth of <= 72
                                feet. A detachment dives to locate the
                                suspected ordnance. Once located, a
                                single explosive charge (10-20 lbs NEW)
                                is placed next to the ordnance to
                                neutralize it. The neutralized mine is
                                then raised, towed to shore, and
                                beached.
Floating Mine................  Personnel are inserted into the ocean via
1 day........................   helicopter or 24-foot vessel, swim to
                                the floating mine in water depths of
                                less than 72 feet, and place a single
                                explosive countercharge (less than 5 lbs
                                NEW) on the mine. The team retreats a
                                safe distance prior to command
                                detonation of a single countercharge.
Dive Platoon.................  Divers are inserted into the ocean via
1 day........................   helicopter or 24-foot vessel, dive to
                                depths of 30-72 feet and detonate
                                sequential charges on an inert mine
                                shape placed on the bottom with 3.5 lbs
                                NEW.
Very Shallow Water Mine        Locating, identifying, and neutralizing
 Counter Measure.               mines (placing explosives on mines for
1 day........................   the purposes of destroying them) placed
                                either mid-column or on the sea floor at
                                a water depth of <= 24 feet (10-20 lbs
                                NEW). Use of explosives will occur
                                during approximately 60% of training
                                events and will ONLY occur in the SSTC
                                oceanside Boat Lanes. All in-Bay
                                training (40%) will not use any
                                explosives. Personnel are transported to
                                a location in one to two RHIBs and place
                                transponders into the water. The
                                transponders hover over the bottom to
                                provide divers with shallow-water
                                navigation instruction.
Unmanned Underwater Vehicle    Training on use of UUVs. One to two RHIBs
 (UUV).                         are used to transport personnel to a
1 day........................   site. Two transponders are placed in the
                                water, with an UUV between them. UUVs
                                explore the area, photograph, and
                                collect hydrographic information. After
                                analysis is complete, appropriate Navy
                                marine mammals are dispatched to
                                localize and mark potential objects,
                                followed by divers who clear the area of
                                identified hazards. Approximately 3% of
                                events involve placing a single 10-15
                                lbs NEW charge in water depths from 10
                                to 72 feet on the oceanside of SSTC-
                                NORTH (on the bottom or up to 20 feet
                                from the surface) to neutralize a
                                simulated mine. Use and detonation of
                                explosives will only occur in the SSTC
                                oceanside Boat Lanes 1-14. Bayside UUV
                                use in the Bay will be for operator
                                training and not contain explosives.
MK8 Marine Mammal/Marine       Navy divers work with the help of the
 Mammal Systems (MMS).          Navy's trained marine mammals to detect
1 day........................   underwater objects. Approximately 10% of
                                training involves the setting of a 13-
                                or 29 lbs NEW charge to detonate the
                                objects. Sequential detonations operate
                                at water depths of 10 to 72 feet and are
                                bottom laid. Single charges are laid
                                within water depths of 24 to 72 feet, 20
                                feet from the surface or below. Use of
                                explosives will only occur in the SSTC
                                oceanside Boat Lanes 1-14.
Mine Neutralization..........  Personnel are inserted via helicopter or
                                vessel for underwater demolition
                                training consisting of eight sequential
                                charges placed on the sea floor using
                                3.5 lbs NEW explosive charges on various
                                inert mine shapes in water depths of 30
                                to 72 feet to maintain qualifications.
Surf Zone Test Detachment      To support clearance capability in the
 Equipment T&E.                 surf zone (out to 10 feet of water), EOD
1 day........................   would test and evaluate the
                                effectiveness of new detection and
                                neutralization equipment (i.e.,
                                generally explosive counter-techniques
                                to safely disarm/render safe mines) in
                                surf conditions. Use of explosives will
                                occur during 1% of training events (0.1
                                to 20 lbs NEW) and will only occur in
                                the SSTC oceanside Boat Lanes 1-14.
Unmanned Underwater Vehicle    Training consists of placing 2 sequential
 Neutralization.                charges consisting of a Seafox (3.3 lbs)
1 day........................   or Archerfish (3.57 lbs) charge placed
                                from depths of 10 feet to the bottom in
                                water depth less than 72 feet.
Airborne Mine Neutralization   The training would involve an MH-60S
 System (AMNS).                 helicopter deploying an AMNS underwater
1 day........................   vehicle into the water that searches
                                for, locates, and destroys mines. The
                                vehicle is self-propelled and unmanned.
                                Approximately 20% of the training would
                                involve the AMNS being remotely
                                detonated (3.5 lbs NEW) when it
                                encounters a simulated (inert) mine
                                shape.
Naval Special Warfare          Demolition Requalifications and Training
 Underwater Demolition          provides teams with experience in
 Qualification/Certification.   underwater detonations by conducting
1 day........................   detonations on metal plates near the
                                shoreline. At water depths of 10 to 72
                                feet two sequential 12.5-13.75 lbs NEW
                                charges are placed on the bottom or a
                                single 25.5 lbs charge is placed from a
                                depth of 20 feet to the bottom.
Naval Special Warfare          Up to 40 persons participate in the
 Underwater Demolition          activity, which involves small groups
 Training.                      swimming to shore from four inflatable
1 day........................   boats located approximately 1,000 yards
                                offshore; boats may be beached on shore.
                                A single charge of less than 10 lbs NEW
                                (if detonated on the bottom) or less
                                than 3.6 lbs NEW (if within five feet of
                                the surface) is manually detonated near
                                the shoreline in water less than 24 feet
                                deep.

[[Page 64279]]

 
SEAL Delivery Vehicle/         Designed to certify SDV Team operators
 Advanced SEAL Delivery         for deployment, events include direct
 System Certification to        action, reconnaissance, and/or counter-
 Deploy.                        terrorism events. Training may include
14 days......................   navigation runs into and out of the San
                                Diego Bay, hydrographic reconnaissance,
                                over the beach (OBT) training, combat
                                swimmer, and underwater detonation
                                training. Based on training tempo,
                                multiple events could occur. Underwater
                                detonation events involve a single timed
                                charge of 10 lbs or less NEW in water
                                depths of 24 feet or less placed from
                                mid-water column to the seafloor that
                                may be conducted in coordination with
                                other training events. Use of explosives
                                will only occur in the SSTC oceanside
                                Boat Lanes 1-10. The whole Certification
                                process is a 14 day evolution, although
                                explosives would not be used every day.
------------------------------------------------------------------------

    Table 2 shows the underwater detonation training event types 
described above along with the net equivalent weight (NEW) for the 
charges involved, water depth, and number of events per year. NEW is a 
conversion that allows the comparison of different mixes of explosive 
formulas. Since different explosive formulas may have different 
explosive potentials, explosive potentials are often normalized and 
expressed as compared to the equivalent explosive potential of TNT 
(trinitrotoluene). While explosive NEW shown in Table 2 range from 0.03 
lbs to 29 lbs, it should be noted that approximately 78% of the annual 
underwater detonation training events at the SSTC would use explosive 
weights less than 10 lbs (see Figure 2-2 of the Navy's IHA 
application).

                                                    Table 2--SSTC Annual Underwater Explosive Events
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                         No. of
 Underwater detonation training        NEW  (lbs)       No. of  sequential   Water depth (feet)     Charge depth        training        SSTC  location
              event                                        detonations                                                 events/yr*
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shock wave action generator       0.033..............  1/det..............  10-20..............  Mid-water.........              74  SDB.**
 (SWAG).
Shock wave action generator       0.033..............  1/det..............  10-20..............  Mid-water.........              16  Oceanside.
 (SWAG).
Mine Counter Measure............  10-20..............  1/det..............  <= 72..............  Mid-water.........              29  Oceanside.
Mine Counter Measure............  10-20..............  1/det..............  <= 72..............  Bottom............              29  Oceanside.
Floating Mine...................  <= 5...............  1/det..............  <= 72..............  Surface (< 5 ft)..              53  Oecanside.
Dive Platoon....................  3.5................  1/det..............  39-72..............  Bottom............               8  Oceanside.
Very Shallow Water Mine Counter   0.1-20.............  1/det..............  <= 24..............  Bottom............              60  Oceanside.
 Measure.
Unmanned underwater vehicle.....  10-15..............  1/det..............  10-72..............  Bottom to 10 ft                  4  Oceanside.
                                                                                                  from surface.
Marine Mammal System............  13 & 29............  2/det..............  10-72..............  Bottom............               8  Oceanside.
Marine Mammal System Operator     13 & 29............  1/det..............  24-72..............  Bottom to 20 ft                  8  Oceanside.
 Course.                                                                                          from surface.
Mine Neutralization.............  3.5................  8/det..............  30-72..............  Bottom............               4  Oceanside.
Surf Zone Testing and Evaluation  to 20..............  1/det..............  <= 24..............  Bottom............               2  Oceanside.
Unmanned Underwater Vehicle       3.3 & 3.57.........  2/det..............  10-72..............  Bottom to 10 ft                  4  Oceanside.
 Neutralization.                                                                                  from surface.
Airborne Mine Neutralization      3.53...............  1/det..............  40-72..............  Mid-water to                    10  Oceanside.
 System.                                                                                          bottom.
Qualification/Certification.....  12.5-13.75.........  2/det..............  10-72..............  Bottom............               8  Oceanside.
Qualification/Certification.....  25.5...............  1/det..............  40-72..............  Bottom to 20 ft                  4  Oceanside.
                                                                                                  from surface.
Naval Special Warfare Demolition  <= 10..............  1/det..............  <= 24..............  Bottom............               4  Oceanside.
 Training.
Naval Special Warfare Demolition  <= 3.6.............  1/det..............  <= 24..............  Surface...........               8  Oceanside.
 Training.
SEAL Delivery Vehicle/Advance     <= 10..............  1/det..............  <= 24..............  Bottom to mid-                  40  Oceanside.
 SEAL Delivery Vehicle.                                                                           water.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* No. of training events is the total amount of underwater detonation training involving each particular Training Event Type. Most Training events are a
  single detonation (i.e., 1/detonation) per event. However, four of these Training Event Types involve sequential charges during the same training
  event. Sequential charges are either conducted with a 10-second delay between detonations or 30-minute delay between detonations.
** San Diego Bay.

Elevated Causeway System (ELCAS) Training

    Elevated Causeway System (ELCAS) is a modular pre-fabricated 
causeway pier. ELCAS provides a link between offshore amphibious supply 
ships with associated lighterage (i.e., small cargo boats and barges) 
and the shore by bridging the surf zone. Offloaded vehicles and 
supplies can be driven on the causeway to and from shore.
    ELCAS events would occur up to four times a year at either the 
dedicated training lane within bayside Bravo Beach, or in the oceanside 
training lanes at SSTC-North. During ELCAS training events, 24-inch 
wide hollow steel piles are driven into the sand in the surf zone with 
an impact hammer. Pile installation occurs over a period of 
approximately 10 days and pile removal over approximately three days. 
Approximately 101 piles are driven into the beach and surf zone with a 
diesel impact hammer over the course of approximately 10 days, 24 hours 
a day (i.e., during the day and night). Each pile takes an average of 
10 minutes to install, with around 250 to 300 impacts per pile. Pile 
driving includes a semi-soft start as part of the normal operating 
procedure based on the design of the drive equipment. The pile driver 
increases impact strength as resistance goes up. At first, the pile 
driver piston

[[Page 64280]]

drops a few inches. As resistance goes up, the pile driver piston will 
drop from a higher distance thus providing more impact due to gravity. 
The pile driver can take 5 to 7 minutes to reach full impact strength. 
As sections of piles are installed, causeway platforms are then hoisted 
and secured onto the piles with hydraulic jacks and cranes. The ELCAS 
is then used for a period of time, usually less than two weeks to 
transfer cargo back and forth from sea to shore.
    At the end of all the ELCAS training, a vibratory hammer attached 
to the pile head will be used to remove piles by applying a rapidly 
alternating force to the pile by rotating eccentric weights about 
shafts, resulting in an upward vibratory force on the pile. The 
vertical vibration in the pile disturbs or ``liquefies'' the sediment 
next to the pile causing the sediment particles to lose their 
frictional grip on the pile. This also allows sediment to fill back 
into the hole that is left after the pile is removed. Removal takes 
approximately 15 minutes per pile over a period of around 3 days.
    In relation to this IHA application, installation and removal of 
ELCAS support piles were deemed by the Navy to most likely have the 
potential to harass marine mammals.

Other Training

    In addition to underwater detonations and ELCAS, the Navy performs 
a variety of other shallow water and amphibious training at SSTC. This 
training includes amphibious vessel and vehicle maneuvering, beach 
landings, causeway (floating pier) insertions onto the beach, swimming, 
land demolitions, transfer of fluids from vessel to the shore through a 
flexible conduit (seawater is used as the fluid during training), and 
helicopter overflight events.
    Potential impacts from other training applicable to marine mammals 
included helicopter overflights, and marine boat and vessel movement 
within the SSTC. However, as discussed in detail in the Navy's IHA 
application, the Navy determined that only underwater detonations and 
ELCAS pile driving and pile removal training events at SSTC have the 
potential to rise to the level of harassment as defined under the MMPA, 
as amended in 1994. NMFS agrees with the Navy's determination.

Description of Marine Mammals in the Area of the Specified Activity

    There are four marine mammal species within SSTC marine waters with 
confirmed or historic occurrence in the study area. These include the 
California sea lion (Zalophus californianus), Pacific harbor seal 
(Phoca vitulina richardsii), California coastal stock of bottlenose 
dolphin (Tursiops truncatus), and more infrequently gray whale 
(Eschrichtius robustus). None are listed as threatened or endangered 
under the Endangered Species Act (ESA).
    The Navy's IHA application contains information on the status, 
distribution, seasonal distribution, and abundance of each of the 
species under NMFS jurisdiction mentioned in this document. Please 
refer to the application for that information (see ADDRESSES). 
Additional information can also be found in the NMFS Stock Assessment 
Reports (SAR). The Pacific 2009 SAR is available at: http://www.nmfs.noaa.gov/pr/pdfs/sars/po2009.pdf.

California Sea Lions

    The California sea lion is by far the most commonly-sighted 
pinniped species at sea or on land in the vicinity of the SSTC. Nearly 
all of the U.S. Stock (more than 95%) of California sea lion breeds and 
gives birth to pups on San Miguel, San Nicolas, and Santa Barbara 
islands off California. Smaller numbers of pups are born on the 
Farallon Islands, and A[ntilde]o Nuevo Island (Lowry et al. 1992). In 
California waters, sea lions represented 97% (381 of 393) of identified 
pinniped sightings at sea during the 1998-1999 NMFS surveys (Carretta 
et al. 2000). They were sighted during all seasons and in all areas 
with survey coverage from nearshore to offshore areas (Carretta et al. 
2000).
    Survey data from 1975 to 1978 were analyzed to describe the 
seasonal shifts in the offshore distribution of California sea lions 
(Bonnell and Ford 1987). During summer, the highest densities were 
found immediately west of San Miguel Island. During autumn, peak 
densities of sea lions were centered on Santa Cruz Island. During 
winter and spring, peak densities occurred just north of San Clemente 
Island. The seasonal changes in the center of distribution were 
attributed to changes in the distribution of the prey species. If 
California sea lion distribution is determined primarily by prey 
abundance as influenced by variations in local, seasonal, and inter-
annual oceanographic variation, these same areas might not be the 
center of sea lion distribution every year. Costa et al. (2007) was 
able to indentify kernel home range contours for foraging female sea 
lions during non-El Nino conditions, although there was some variation 
over the three years of this tagging study. Melin et al. (2008) showed 
that foraging female sea lions showed significant variability in 
individual foraging behavior, and foraged farther offshore and at 
deeper depths during El Nino years as compared to non-El Nino years. 
The distribution and habitat use of California sea lions vary with the 
sex of the animals and their reproductive phase. Adult males haul out 
on land to defend territories and breed from mid-to-late May until late 
July. The pupping and mating season for sea lions begins in late May 
and continues through July (Heath 2002). Individual males remain on 
territories for 27-45 days without going to sea to feed. During August 
and September, after the mating season, the adult males migrate 
northward to feeding areas as far away as Washington (Puget Sound) and 
British Columbia (Lowry et al. 1992). They remain there until spring 
(March-May), when they migrate back to the breeding colonies. Thus, 
adult males are present in offshore areas of the SSTC only briefly as 
they move to and from rookeries. Distribution of immature California 
sea lions is less well known, but some make northward migrations that 
are shorter in length than the migrations of adult males (Huber 1991). 
However, most immature sea lions are presumed to remain near the 
rookeries, and thus remain near SSTC for most of the year (Lowry et al. 
1992). Adult females remain near the rookeries throughout the year. 
Most births occur from mid-June to mid-July (peak in late June).
    California sea lions feed on a wide variety of prey, including 
Pacific whiting, northern anchovy, mackerel, squid, sardines, and 
rockfish (Antonelis et al. 1990; Lowry et al. 1991; Lowry and Carretta 
1999; Lowry and Forney 2005; Bearzi 2006). In Santa Monica Bay, 
California sea lions are known to follow and feed near bottlenose 
dolphins (Bearzi 2006), and if in the near shore waters of SSTC, may 
forage on common coastal beach fish species (corbina and barred 
surfperch) as dolphins (Allen 2006).
    There are limited published at-sea density estimates for pinnipeds 
within Southern California. Higher densities of California sea lions 
are observed during cold-water months. At-sea densities likely decrease 
during warm-water months because females spend more time ashore to give 
birth and attend to their pups. Radio-tagged female California sea 
lions at San Miguel Island spent approximately 70% of their time at sea 
during the non-breeding season (cold-water months) and pups spent an 
average of 67% of their time ashore during their mother's absence 
(Melin and DeLong 2000). Different age classes of California sea lions 
are found in the offshore areas of SSTC throughout the year (Lowry et 
al. 1992). Although adult male California sea lions feed in areas

[[Page 64281]]

north of SSTC, animals of all other ages and sexes spend most, but not 
all, of their time feeding at sea during winter, thus, the winter 
estimates likely are somewhat low. During warm-water months, a high 
proportion of the adult males and females are hauled out at terrestrial 
sites during much of the period, so the summer estimates are low to a 
greater degree.
    The NMFS population estimate of the U.S. Stock of California sea 
lions is 238,000 (Carretta et al. 2010), with a minimum estimate based 
on a 2005 shore-based survey of all age and sex classes of 141,842 
(NMFS, unpublished data, Carretta et al. 2010). The California sea lion 
is not listed under the ESA, and the U.S. Stock, some of which occurs 
in the SSTC, is not considered a strategic stock under the MMPA.

Pacific Harbor Seal

    Harbor seals are considered abundant throughout most of their range 
from Baja California to the eastern Aleutian Islands. An unknown number 
of harbor seals also occur along the west coast of Baja California, at 
least as far south as Isla Asuncion, which is about 100 miles south of 
Punta Eugenia. Animals along Baja California are not considered to be a 
part of the California stock because it is not known if there is any 
demographically significant movement of harbor seals between California 
and Mexico (Carretta et al. 2010). Peak numbers of harbor seals haul 
out on land during late May to early June, which coincides with the 
peak of their molt. They generally favor sandy, cobble, and gravel 
beaches (Stewart and Yochem 1994; 2000), and most haul out on the 
central California mainland and Santa Cruz Island (Lowry and Carretta 
2003; Carretta et al. 2010).
    There are limited at-sea density estimates for pinnipeds within 
Southern California. Harbor seals do not make extensive pelagic 
migrations, but do travel 300-500 km on occasion to find food or 
suitable breeding areas (Herder 1986; Carretta et al. 2007). Nursing of 
pups begins in late February, and pups start to become weaned in May. 
Breeding occurs between late March and early May on the southern and 
northern Channel Islands. When at sea during May and June (and March to 
May for breeding females), they generally remain in the vicinity of 
haul-out sites and forage close to shore in relatively shallow waters. 
Based on likely foraging strategies, Grigg et al. (2009) reported 
seasonal shifts in harbor seal movements based on prey availability.
    Harbor seals are opportunistic feeders that adjust their feeding to 
take advantage of locally and seasonally abundant prey which can 
include small crustaceans, rock fish, cusk-eel, octopus, market squid, 
and surfperch (Bigg 1981; Payne and Selzer 1989; Stewart and Yochem 
1994; Stewart and Yochem 2000; Baird 2001; Oates 2005). If in the near 
shore waters of SSTC, harbor seals may forage on common coastal beach 
fish species, such as corbina and barred surfperch (Allen 2006).
    Harbor seals are found in the SSTC throughout the year (Carretta et 
al. 2000) with local densities estimated at 0.010 animals/km\2\ during 
the warm season and 0.020 animals/km\2\ during the cold season.
    Based on the most recent harbor seal counts (26,333 in May-July 
2004, Lowry et al. 2005) and Hanan's revised correction factor, the 
harbor seal population in California is estimated by NMFS to number 
34,233 (Carretta et al. 2010). The minimum size of the California 
harbor seal population is 31,600 (Carretta et al. 2010). Of the 
estimated California population (34,233), less than 30% are thought to 
reside within Southern California due to lack of suitable haul-out 
sites because of significant beach urbanization (Lowry et al. 2008).
    The harbor seal is not listed under the ESA, and the California 
Stock, some of which occurs in the SSTC, is not considered a strategic 
stock under the MMPA. The California population has increased from the 
mid-1960s to the mid-1990s, although the rate of increase may have 
slowed during the 1990s as the population has reached and may be 
stabilizing at carrying capacity (Hanan 1996, Carretta et al. 2010).

Bottlenose Dolphin

    There are two distinct populations of bottlenose dolphins within 
southern California, a coastal population found within 0.5 nm (0.9 km) 
of shore and a larger offshore population (Hansen 1990; Bearzi et al. 
2009). The California Coastal Stock is the only one of these two stocks 
likely to occur within the SSTC. The bottlenose dolphin California 
Coastal Stock occurs at least from Point Conception south into Mexican 
waters, at least as far south as San Quintin, Mexico. In southern 
California, animals are found within 1,600 ft (500 m) of the shoreline 
99% of the time and within 820 ft (250 m) 90% of the time (Hanson and 
Defran 1993). Occasionally, during warm-water incursions such as during 
the 1982-1983 el Ni[ntilde]o event, their range extends as far north as 
Monterey Bay (Wells et al. 1990). Bottlenose dolphins in the Southern 
California Bight (SCB) appear to be highly mobile within a relatively 
narrow coastal zone (Defran et al. 1999), and exhibit no seasonal site 
fidelity to the region (Defran and Weller 1999). There is little site 
fidelity of coastal bottlenose dolphins along the California coast; 
over 80% of the dolphins identified in Santa Barbara, Monterey, and 
Ensenada have also been identified off San Diego (Defran et al. 1999; 
Maldini-Feinholz 1996; Carretta et al. 2008; Bearzi et al. 2009). 
Bottlenose dolphins could occur in the SSTC at variable frequencies and 
periods throughout the year based on localized prey availability 
(Defran et al. 1999).
    The Pacific coast bottlenose dolphins feed primarily on surfperches 
(Family Embiotocidae) and croakers (Family Sciaendae) (Norris and 
Prescott 1961; Walker 1981; Schwartz et al. 1992; Hanson and Defran 
1993), and also consume squid (Loligo opalescens) (Schwartz et al. 
1992). The coastal stock of bottlenose dolphin utilizes a limited 
number of fish prey species with up to 74% being various species of 
surfperch or croakers, a group on non-migratory year-round coastal 
inhabitant (Defran et al. 1999; Allen et al. 2006). For Southern 
California, common croaker prey species include spotfin croaker, 
yellowfin croaker, and California corbina, while common surfperch 
species include barred surfperch and walleye surfperch (Allen et al. 
2006). The corbina and barred surfperch are the most common surf zone 
fish where bottlenose dolphins have been observed foraging (Allen et 
al. 2006). Defran et al. (1999) postulated that the coastal stock of 
bottlenose dolphins showed significant movement within their home range 
(Central California to Mexico) in search of preferred but patchy 
concentrations of near shore prey (i.e., croakers and surfperch). After 
finding concentrations of prey, animals may then forage within a more 
limited spatial extent to take advantage of this local accumulation 
until such time that prey abundance is reduced after which the dolphins 
once again shift location over larger distances (Defran et al. 1999). 
Bearzi (2005) and Bearzi et al. (2009) also noted little site fidelity 
from coastal bottlenose dolphins in Santa Monica Bay, California, and 
that these animals were highly mobile with up to 69% of their time 
spent in travel and dive-travel mode and only 5% of the time in feeding 
behaviors.
    Group size of the California coastal stock of bottlenose dolphins 
has been reported to range from 1 to 57 dolphins (Bearzi 2005), 
although mean pod sizes were around 19.8 (Defran and Weller 1999) and 
10.1 (Bearzi 2005). An at-sea density estimate of 0.202 animals/km\2\ 
was used for acoustic impact modeling for both the warm and cold 
seasons as

[[Page 64282]]

derived in National Center for Coastal Ocean Science (2005).
    Based on photographic mark-recapture surveys conducted along the 
San Diego coast in 2004 and 2005, population size for the California 
Coastal Stock of the bottlenose dolphin is estimated to be 323 
individuals (CV = 0.13, 95% CI 259-430; Dudzik et al. 2005; Carretta et 
al. 2010). This estimate does not reflect that approximately 35% of 
dolphins encountered lack identifiable dorsal fin marks (Defran and 
Weller 1999). If 35% of all animals lack distinguishing marks, then the 
true population size would be closer to 450-500 animals (Carretta et 
al. 2010). The California Coastal Stock of bottlenose dolphins is not 
listed under the ESA, and is not considered a strategic stock under the 
MMPA.

Gray Whale

    The Eastern North Pacific population is found from the upper Gulf 
of California (Tershy and Breese 1991), south to the tip of Baja 
California, and up the Pacific coast of North America to the Chukchi 
and Beaufort seas. There is a pronounced seasonal north-south 
migration. The eastern North Pacific population summers in the shallow 
waters of the northern Bering Sea, the Chukchi Sea, and the western 
Beaufort Sea (Rice and Wolman 1971). The northern Gulf of Alaska (near 
Kodiak Island) is also considered a feeding area; some gray whales 
occur there year-round (Moore et al. 2007). Some individuals spend the 
summer feeding along the Pacific coast from southeastern Alaska to 
central California (Sumich 1984; Calambokidis et al. 1987; 2002). 
Photo-identification studies indicate that gray whales move widely 
along the Pacific coast and are often not sighted in the same area each 
year (Calambokidis et al. 2002). In October and November, the whales 
begin to migrate southeast through Unimak Pass and follow the shoreline 
south to breeding grounds on the west coast of Baja California and the 
southeastern Gulf of California (Braham 1984; Rugh 1984). The average 
gray whale migrates 4,050 to 5,000 nm (7,500 to 10,000 km) at a rate of 
80 nm (147 km) per day (Rugh et al. 2001; Jones and Swartz 2002). 
Although some calves are born along the coast of California (Shelden et 
al. 2004), most are born in the shallow, protected waters on the 
Pacific coast of Baja California from Morro de Santo Domingo (28 
[deg]N) south to Isla Creciente (24 [deg]N) (Urb[aacute]n et al. 2003). 
Main calving sites are Laguna Guerrero Negro, Laguna Ojo de Liebre, 
Laguna San Ignacio, and Estero Soledad (Rice et al. 1981).
    A group of gray whales known as the Pacific Coast Feeding 
Aggregation (PCFA) feeds along the Pacific coast between southeastern 
Alaska and northern to central California throughout the summer and 
fall (NMFS 2001; Calambokidis et al. 2002; Calambokidis et al. 2004). 
The gray whales in this feeding aggregation are a relatively small 
proportion (a few hundred individuals) of the overall eastern North 
Pacific population and typically arrive and depart from these feeding 
grounds concurrently with the migration to and from the wintering 
grounds (Calambokidis et al. 2002; Allen and Angliss 2010). Although 
some site fidelity is known to occur, there is generally considerable 
inter-annual variation since many individuals do not return to the same 
feeding site in successive years (Calambokidis et al. 2000; 
Calambokidis et al. 2004).
    The Eastern North Pacific stock of gray whale transits through 
Southern California during its northward and southward migrations 
between December and June. Gray whales follow three routes from within 
15 to 200 km from shore (Bonnell and Dailey 1993). The nearshore route 
follows the shoreline between Point Conception and Point Vicente but 
includes a more direct line from Santa Barbara to Ventura and across 
Santa Monica Bay. Around Point Vicente or Point Fermin, some whales 
veer south towards Santa Catalina Island and return to the nearshore 
route near Newport Beach. Others join the inshore route that includes 
the northern chain of the Channel Islands along Santa Cruz Island and 
Anacapa Island and east along the Santa Cruz Basin to Santa Barbara 
Island and the Osborn Bank. From here, gray whales migrate east 
directly to Santa Catalina Island and then to Point Loma or Punta 
Descanso or southeast to San Clemente Island and on to the area near 
Punta Banda. A significant portion of the Eastern North Pacific stock 
passes by San Clemente Island and its associated offshore waters 
(Carretta et al. 2000). The offshore route follows the undersea ridge 
from Santa Rosa Island to the mainland shore of Baja California and 
includes San Nicolas Island and Tanner and Cortes banks (Bonnell and 
Dailey 1993).
    Peak abundance of gray whales off the coast of San Diego is 
typically January during the southward migration and in March during 
the migration north, although females with calves, which depart Mexico 
later than males or females without calves, can be sighted from March 
through May or June (Leatherwood 1974; Poole 1984; Rugh et al. 2001; 
Stevick et al. 2002; Angliss and Outlaw 2008). Gray whales would be 
expected to be infrequent migratory transients within the out portions 
of SSTC only during cold-water months (Carretta et al. 2000). Migrating 
gray whale that might infrequently transit through SSTC would not be 
expected to forage, and would likely be present for minutes to less 
than one or two hours at typical travel speeds of 3 knots 
(approximately 3.5 miles per hour) (Perryman et al. 1999; Mate and 
Urb[aacute]n-Ramirez 2003). A mean group size of 2.9 gray whales was 
reported for both coastal (16 groups) and non-coastal (15 groups) areas 
around San Clemente Island (Carretta et al. 2000). The largest group 
reported was nine animals. The largest group reported by the U.S. Navy 
(1998) was 27 animals. Gray whales would not be expected in the SSTC 
from July through November (Rice et al. 1981), and are excluded from 
warm season analysis. Even though gray whale transitory occurrence is 
infrequent along SSTC, a cold season density is estimated at 0.014 
animals per km\2\ for purposes of conservative analysis.
    Systematic counts of gray whales migrating south along the central 
California coast have been conducted by shore-based observers at 
Granite Canyon most years since 1967. The population size of the 
Eastern North Pacific gray whale stock has been increasing over the 
past several decades at a rate approximately between 2.5 to 3.3% per 
year since 1967. The most recent abundance estimates are based on the 
National Marine Fisheries Service's population estimate of 19,126 
individuals as reported in Allen and Angliss (2010).
    In 1994, due to steady increases in population abundance, the 
Eastern North Pacific stock of gray whales was removed from the List of 
Endangered and Threatened Wildlife, as it was no longer considered 
endangered or threatened under the ESA (Allen and Angliss 2010). The 
Eastern North Pacific stock of gray whale is not considered a strategic 
stock under the MMPA. Even though the stock is within Optimal 
Sustainable Population, abundance will rise and fall as the population 
adjusts to natural and man-caused factors affecting the carrying 
capacity of the environment (Rugh et al. 2005). In fact, it is expected 
that a population close to or at the carrying capacity of the 
environment will be more susceptible to fluctuations in the environment 
(Moore et al. 2001).

Potential Effects on Marine Mammals and Their Habitat

    Anticipated impacts resulting from the Navy's proposed SSTC 
training activities include disturbance from

[[Page 64283]]

underwater detonation events and pile driving from the ELCAS events, if 
marine mammals are in the vicinity of these action areas.

Impacts From Anthropogenic Noise

    Marine mammals exposed to high intensity sound repeatedly or for 
prolonged periods can experience hearing threshold shift (TS), which is 
the loss of hearing sensitivity at certain frequency ranges (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is 
unrecoverable, or temporary (TTS), in which case the animal's hearing 
threshold will recover over time (Southall et al. 2007). Since marine 
mammals depend on acoustic cues for vital biological functions, such as 
orientation, communication, finding prey, and avoiding predators, 
marine mammals that suffer from PTS or TTS will have reduced fitness in 
survival and reproduction, either permanently or temporarily. Repeated 
noise exposure that leads to TTS could cause PTS.
    Measured source levels from impact pile driving can be as high as 
214 dB re 1 [mu]Pa @ 1 m. Although no marine mammals have been shown to 
experience TTS or PTS as a result of being exposed to pile driving 
activities, experiments on a bottlenose dolphin (Tursiops truncates) 
and beluga whale (Delphinapterus leucas) showed that exposure to a 
single watergun impulse at a received level of 207 kPa (or 30 psi) 
peak-to-peak (p-p), which is equivalent to 228 dB re 1 [mu]Pa (p-p), 
resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, 
respectively. Thresholds returned to within 2 dB of the pre-exposure 
level within 4 minutes of the exposure (Finneran et al. 2002). No TTS 
was observed in the bottlenose dolphin. Although the source level of 
pile driving from one hammer strike is expected to be much lower than 
the single watergun impulse cited here, animals being exposed for a 
prolonged period to repeated hammer strikes could receive more noise 
exposure in terms of SEL than from the single watergun impulse 
(estimated at 188 dB re 1 [mu]Pa\2\-s) in the aforementioned experiment 
(Finneran et al. 2002).
    However, in order for marine mammals to experience TTS or PTS, the 
animals have to be close enough to be exposed to high intensity noise 
levels for prolonged period of time. Current NMFS standards for 
preventing injury from PTS and TTS is to require shutdown or power-down 
of noise sources when a cetacean species is detected within the 
isopleths corresponding to SPL at received levels equal to or higher 
than 180 dB re 1 [mu]Pa (rms), or a pinniped species at 190 dB re 1 
[mu]Pa (rms). Based on the best scientific information available, these 
SPLs are far below the threshold that could cause TTS or the onset of 
PTS. Certain mitigation measures proposed by the Navy, discussed below, 
can effectively prevent the onset of TS in marine mammals, by 
establishing safety zones and monitoring safety zones during the 
training exercise.
    In addition, chronic exposure to excessive, though not high-
intensity, noise could cause masking at particular frequencies for 
marine mammals that utilize sound for vital biological functions. 
Masking can interfere with detection of acoustic signals such as 
communication calls, echolocation sounds, and environmental sounds 
important to marine mammals. Therefore, like TS, marine mammals whose 
acoustical sensors or environment are being masked are also impaired 
from maximizing their performance fitness in survival and reproduction.
    Masking occurs at the frequency band which the animals utilize. 
Therefore, since noise generated from the proposed underwater 
detonation and pile driving and removal is mostly concentrated at low 
frequency ranges, it may have less effect on high frequency 
echolocation sounds by killer whales. However, lower frequency man-made 
noises are more likely to affect detection of communication calls and 
other potentially important natural sounds such as surf and prey noise. 
It may also affect communication signals when they occur near the noise 
band used by the animals and thus reduce the communication space of 
animals (e.g., Clark et al. 2009) and cause increased stress levels 
(e.g., Foote et al. 2004; Holt et al. 2009).
    Masking can potentially impact marine mammals at the individual, 
population, community, or even ecosystem levels (instead of individual 
levels caused by TS). Masking affects both senders and receivers of the 
signals and can potentially have long-term chronic effects on marine 
mammal species and populations in certain situations. Recent science 
suggests that low frequency ambient sound levels have increased by as 
much as 20 dB (more than 3 times in terms of SPL) in the world's ocean 
from pre-industrial periods, and most of these increases are from 
distant shipping (Hildebrand 2009). All anthropogenic noise sources, 
such as those from underwater explosions and pile driving, contribute 
to the elevated ambient noise levels and, thus intensify masking. 
However, single detonations are unlikely to contribute much to masking.
    Since all of the underwater detonation events and ELCAS events are 
planned in a very shallow water situation (wave length >> water depth), 
where low frequency propagation is not efficient, the noise generated 
from these activities is predominantly in the low frequency range and 
is not expected to contribute significantly to increased ocean ambient 
noise.
    Finally, exposure of marine mammals to certain sounds could lead to 
behavioral disturbance (Richardson et al. 1995). Behavioral responses 
to exposure to sound and explosions can range from no observable 
response to panic, flight and possibly more significant responses as 
discussed previously (Richardson et al. 1995; Southall et al. 2007). 
These responses include: changing durations of surfacing and dives, 
number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities, changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping), avoidance of areas where noise sources are located, and/or 
flight responses (e.g., pinnipeds flushing into water from haulouts or 
rookeries) (Reviews by Richardson et al. 1995; Wartzok et al. 2003; Cox 
et al. 2006; Nowacek et al. 2007; Southall et al. 2007).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and reproduction. Some of these 
significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cease feeding or social interaction.
    For example, at the Guerreo Negro Lagoon in Baja California, 
Mexico, which is one of the important breeding grounds for Pacific gray 
whales, shipping and dredging associated with a salt works may have 
induced gray whales to abandon the area through most of the 1960s 
(Bryant et al. 1984). After these activities stopped, the lagoon was 
reoccupied, first by single whales and later by cow-calf pairs.
    The onset of behavioral disturbance from anthropogenic noise 
depends on

[[Page 64284]]

both external factors (characteristics of noise sources and their 
paths) and the receiving animals (hearing, motivation, experience, 
demography) and is also difficult to predict (Southall et al. 2007).
    However, the proposed action area is not believed to be a prime 
habitat for marine mammals, nor is it considered an area frequented by 
marine mammals. Therefore, behavioral disturbances that could result 
from anthropogenic construction noise associated with the Navy's 
proposed training activities are expected to affect only a small number 
of marine mammals on an infrequent basis.

Impacts From Underwater Detonations at Close Range

    In addition to noise induced disturbances and harassment, marine 
mammals could be killed or injured by underwater explosions due to the 
impacts to air cavities, such as the lungs and bubbles in the 
intestines, to the shock wave (Elsayed 1997; Elsayed and Gorbunov 
2007). The criterion for mortality and non-auditory injury used in MMPA 
take authorization is the onset of extensive lung hemorrhage and slight 
lung injury or ear drum rupture, respectively (see Table 3). Extensive 
lung hemorrhage is considered debilitating and potentially fatal as a 
result of air embolism or suffocation. In this Incidental Harassment 
Authorization application, all marine mammals within the calculated 
radius for 1% probability of onset of extensive lung injury (i.e., 
onset of mortality) are counted as lethal exposures. The range at which 
1% probability of onset of extensive lung hemorrhage is expected to 
occur is greater than the ranges at which 50% to 100% lethality would 
occur from closest proximity to the charge or from presence within the 
bulk cavitation region. (The region of bulk cavitation is an area near 
the surface above the detonation point in which the reflected shock 
wave creates a region of cavitation within which smaller animals would 
not be expected to survive). Because the range for onset of extensive 
lung hemorrhage for smaller animals exceeds the range for bulk 
cavitation and all more serious injuries, all smaller animals within 
the region of cavitation and all animals (regardless of body mass) with 
more serious injuries than onset of extensive lung hemorrhage are 
accounted for in the lethal exposures estimate. The calculated maximum 
ranges for onset of extensive lung hemorrhage depend upon animal body 
mass, with smaller animals having the greatest potential for impact, as 
well as water column temperature and density.
    However, due to the small detonation that would be used in the 
proposed SSTC training activities and the resulting small safety zones 
to be monitored and mitigated for marine mammals in the vicinity of the 
proposed action area, it is unlikely that marine mammals would be 
killed or injured by underwater detonations.

Impact Criteria and Thresholds

    The effects of an at-sea explosion or pile driving on a marine 
mammal depends on many factors, including the size, type, and depth of 
both the animal and the explosive charge/pile being driven; the depth 
of the water column; the standoff distance between the charge/pile and 
the animal; and the sound propagation properties of the environment. 
Potential impacts can range from brief acoustic effects (such as 
behavioral disturbance), tactile perception, physical discomfort, 
slight injury of the internal organs and the auditory system, to death 
of the animal (Yelverton et al. 1973; O'Keeffe and Young 1984; DoN 
2001). Non-lethal injury includes slight injury to internal organs and 
the auditory system; however, delayed lethality can be a result of 
individual or cumulative sub-lethal injuries (DoN 2001). Short-term or 
immediate lethal injury would result from massive combined trauma to 
internal organs as a direct result of proximity to the point of 
detonation or pile driving (DoN 2001).
    This section summarizes the marine mammal impact criteria used for 
the subsequent modeled calculations. Several standard acoustic metrics 
(Urick 1983) are used to describe the thresholds for predicting 
potential physical impacts from underwater pressure waves:
     Total energy flux density or Sound Exposure Level (SEL). 
For plane waves (as assumed here), SEL is the time integral of the 
instantaneous intensity, where the instantaneous intensity is defined 
as the squared acoustic pressure divided by the characteristic 
impedance of sea water. Thus, SEL is the instantaneous pressure 
amplitude squared, summed over the duration of the signal and has dB 
units referenced to 1 re [micro]Pa\2\-s.
     \1/3\-octave SEL. This is the SEL in a \1/3\-octave 
frequency band. A \1/3\-octave band has upper and lower frequency 
limits with a ratio of 21:3, creating bandwidth limits of about 23 
percent of center frequency.
     Positive impulse. This is the time integral of the initial 
positive pressure pulse of an explosion or explosive-like wave form. 
Standard units are Pa-s, but psi-ms also are used.
     Peak pressure. This is the maximum positive amplitude of a 
pressure wave, dependent on charge mass and range. Units used here are 
psi, but other units of pressure, such as [micro]Pa and Bar, also are 
used.
1. Harassment Threshold for Sequential Underwater Detonations
    There may be rare occasions when sequential underwater detonations 
are part of a static location event. Sequential detonations are more 
than one detonation within a 24-hour period in a geographic location 
where harassment zones overlap. For sequential underwater detonations, 
accumulated energy over the entire training time is the natural 
extension for energy thresholds since energy accumulates with each 
subsequent shot.
    For sequential underwater detonations, the acoustic criterion for 
behavioral harassment is used to account for behavioral effects 
significant enough to be judged as harassment, but occurring at lower 
sound energy levels than those that may cause TTS. The behavioral 
harassment threshold is based on recent guidance from NMFS (NMFS 2009a; 
2009b) for the energy-based TTS threshold. The research on pure tone 
exposures reported in Schlundt et al. (2000) and Finneran and Schlundt 
(2004) provided the pure-tone threshold of 192 dB as the lowest TTS 
value. The resulting TTS threshold for explosives is 182 dB re 1 
[micro]Pa\2\-s in any \1/3\ octave band. As reported by Schlundt et al. 
(2000) and Finneran and Schlundt (2004), instances of altered behavior 
in the pure tone research generally began 5 dB lower than those causing 
TTS. The behavioral harassment threshold is therefore derived by 
subtracting 5 dB from the 182 dB re 1 [micro]Pa\2\-s in any \1/3\ 
octave band threshold, resulting in a 177 dB re 1 [mu]Pa\2\-s 
behavioral disturbance harassment threshold for multiple successive 
explosives (Table 3).
2. Criteria for ELCAS Pile Driving and Removal
    Since 1997, NMFS has been using generic sound exposure thresholds 
to determine when an activity in the ocean that produces impact sound 
(i.e., pile driving) results in potential take of marine mammals by 
harassment (70 FR 1871). Current NMFS criteria (70 FR 1871) regarding 
exposure of marine mammals to underwater sounds is that cetaceans 
exposed to sound pressure levels (SPLs) of 180 dB root mean squared 
(dBrms in units of dB re 1 [micro]Pa) or higher and 
pinnipeds exposed to 190 dBrms or higher are considered to 
have been taken by Level A (i.e., injurious)

[[Page 64285]]

harassment. Marine mammals (cetaceans and pinnipeds) exposed to impulse 
sounds (e.g., impact pile driving) of 160 dBrms but below 
Level A thresholds (i.e., 180 or 190 dB) are considered to have been 
taken by Level B behavioral harassment. Marine mammals (cetaceans and 
pinnipeds) exposed to non-impulse noise (e.g., vibratory pile driving) 
at received levels of 120 dB RMS or above are considered to have been 
taken by Level B behavioral harassment (Table 3).

   Table 3--Effects Criteria for Underwater Detonations and ELCAS Pile
                             Driving/Removal
------------------------------------------------------------------------
          Criterion           Criterion definition        Threshold
------------------------------------------------------------------------
                      Underwater Explosive Criteria
------------------------------------------------------------------------
Mortality...................  Onset of severe lung  30.5 psi-ms
                               injury (1%            (positive impulse).
                               probability of
                               mortality).
Level A Harassment (Injury).  Slight lung injury;   13.0 psi-ms
                               or.                   (positive impulse).
                              50% of marine         205 dB re 1
                               mammals would         [mu]Pa\2\-s (full
                               experience ear drum   spectrum energy).
                               rupture; and 30%
                               exposed sustain PTS.
Level B Harassment..........  TTS (dual criteria).  23 psi (peak
                                                     pressure;
                                                     explosives <2,000
                                                     lbs), or
                                                    182 dB re 1
                                                     [mu]Pa\2\-s (peak
                                                     \1/3\ octave band).
                              (sequential           177 dB re 1
                               detonations only).    [mu]Pa\2\-s.
------------------------------------------------------------------------
                      Pile Driving/Removal Criteria
------------------------------------------------------------------------
Level A Harassment..........  Pinniped only: PTS    190 dBrms re 1
                               caused by repeated    [mu]Pa.
                               exposure to
                               received levels
                               that cause TTS.
                              Cetacean only: PTS    180 dBrms re 1
                               caused by repeated    [mu]Pa.
                               exposure to
                               received levels
                               that cause TTS.
Level B Behavioral            Impulse noise:        160 dBrms re 1
 Harassment.                   Behavioral            [mu]Pa.
                               modification of
                               animals.
                              Non-impulse noise:    190 dBrms re 1
                               Behavioral            [mu]Pa.
                               modification of
                               animals.
------------------------------------------------------------------------

Assessing Harassment From Underwater Detonations

    Underwater detonations produced during SSTC training events 
represent a single, known source. Chemical explosives create a bubble 
of expanding gases as the material burns. The bubble can oscillate 
underwater or, depending on charge-size and depth, be vented to the 
surface in which case there is no bubble-oscillation with its 
associated low-frequency energy. Explosions produce very brief, 
broadband pulses characterized by rapid rise-time, great zero-to-peak 
pressures, and intense sound, sometimes described as impulse. Close to 
the explosion, there is a very brief, great-pressure acoustic wave-
front. The impulse's rapid onset time, in addition to great peak 
pressure, can cause auditory impacts, although the brevity of the 
impulse can include less SEL than expected to cause impacts. The 
transient impulse gradually decays in magnitude as it broadens in 
duration with range from the source. The waveform transforms to 
approximate a low-frequency, broadband signal with a continuous sound 
energy distribution across the spectrum. In addition, underwater 
explosions are relatively brief, transitory events when compared to the 
existing ambient noise within the San Diego Bay and at the SSTC.
    The impacts of an underwater explosion to a marine mammal are 
dependent upon multiple factors including the size, type, and depth of 
both the animal and the explosive. Depth of the water column and the 
distance from the charge to the animal also are determining factors as 
are boundary conditions that influence reflections and refraction of 
energy radiated from the source. The severity of physiological effects 
generally decreases with decreasing exposure (impulse, sound exposure 
level, or peak pressure) and/or increasing distance from the sound 
source. The same generalization is not applicable for behavioral 
effects, because they do not depend solely on sound exposure level. 
Potential impacts can range from brief acoustic effects, tactile 
perception, and physical discomfort to both lethal and non-lethal 
injuries. Disturbance of ongoing behaviors could occur as a result of 
non-injurious physiological responses to both the acoustic signature 
and shock wave from the underwater explosion. Non-lethal injury 
includes slight injury to internal organs and auditory system. The 
severity of physiological effects generally decreases with decreasing 
sound exposure and/or increasing distance from the sound source. 
Injuries to internal organs and the auditory system from shock waves 
and intense impulsive noise associated with explosions can be 
exacerbated by strong bottom-reflected pressure pulses in reverberant 
environments (Gaspin 1983; Ahroon et al. 1996). Nevertheless, the 
overall size of the explosives used at the SSTC is much smaller than 
those used during larger Fleet ship and aircraft training events.
    All underwater detonations proposed for SSTC were modeled as if 
they will be conducted in shallow water of 24 to 72 feet, including 
those that would normally be conducted in very shallow water (VSW) 
depths of zero to 24 feet. Modeling in deeper than actual water depths 
causes the modeled results to be more conservative (i.e., it 
overestimates propagation and potential exposures) than if the 
underwater detonations were modeled at their actual, representative 
depths when water depth is less than 24 feet.
    The Navy's underwater explosive effects simulation requires six 
major process components:
     A training event description including explosive type;
     Physical oceanographic and geoacoustic data for input into 
the acoustic propagation model representing seasonality of the planned 
operation;
     Biological data for the area including density (and 
multidimensional animal movement for those training events with 
multiple detonations);
     An acoustic propagation model suitable for the source type 
to predict impulse, energy, and peak pressure at ranges and depths from 
the source;
     The ability to collect acoustic and animal movement 
information to predict exposures for all animals during a training 
event (dosimeter record); and
     The ability for post-operation processing to evaluate the 
dosimeter exposure record and calculate exposure

[[Page 64286]]

statistics for each species based on applicable thresholds.
    An impact model, such as the one used for the SSTC analysis, 
simulates the conditions present based on location(s), source(s), and 
species parameters by using combinations of embedded models (Mitchell 
et al. 2008). The software package used for SSTC consists of two main 
parts: An underwater noise model and bioacoustic impact model (Lazauski 
et al. 1999; Lazauski and Mitchell 2006; Lazauski and Mitchell 2008).
    Location-specific data characterize the physical and biological 
environments while exercise-specific data construct the training 
operations. The quantification process involves employment of modeling 
tools that yield numbers of exposures for each training operation.
    During modeling, the exposures are logged in a time-step manner by 
virtual dosimeters linked to each simulated animal. After the operation 
simulation, the logs are compared to exposure thresholds to produce raw 
exposure statistics. It is important to note that dosimeters only were 
used to determine exposures based on energy thresholds, not impulse or 
peak pressure thresholds. The analysis process uses quantitative 
methods and identifies immediate short-term impacts of the explosions 
based on assumptions inherent in modeling processes, criteria and 
thresholds used, and input data. The estimations should be viewed with 
caution, keeping in mind that they do not reflect measures taken to 
avoid these impacts (i.e., mitigations). Ultimately, the goals of this 
acoustic impact model were to predict acoustic propagation, estimate 
exposure levels, and reliably predict impacts.
    Predictive sound analysis software incorporates specific 
bathymetric and oceanographic data to create accurate sound field 
models for each source type. Oceanographic data such as the sound speed 
profiles, bathymetry, and seafloor properties directly affect the 
acoustic propagation model. Depending on location, seasonal variations, 
and the oceanic current flow, dynamic oceanographic attributes (e.g., 
sound speed profile) can change dramatically with time. The sound field 
model is embedded in the impact model as a core feature used to analyze 
sound and pressure fields associated with SSTC underwater detonations.
    The sound field model for SSTC detonations was the Reflection and 
Refraction in Multilayered Ocean/Ocean Bottoms with Shear Wave Effects 
(REFMS) model (version 6.03). The REFMS model calculates the combined 
reflected and refracted shock wave environment for underwater 
detonations using a single, generalized model based on linear wave 
propagation theory (Cagniard 1962; Britt 1986; Britt et al. 1991).
    The model outputs include positive impulse, sound exposure level 
(total and in 1/3-octave bands) at specific ranges and depths of 
receivers (i.e., marine mammals), and peak pressure. The shock wave 
consists of two parts, a very rapid onset ``impulsive'' rise to 
positive peak over-pressure followed by a reflected negative under-
pressure rarefaction wave. Propagation of shock waves and sound energy 
in the shallow-water environment is constrained by boundary conditions 
at the surface and seafloor.
    Multiple locations (in Boat Lanes and Echo area) and charge depths 
were used to determine the most realistic spatial and temporal 
distribution of detonation types associated with each training 
operation for a representative year. Additionally, the effect of sound 
on an animal depends on many factors including:
     Properties of the acoustic source(s): Source level (SL), 
spectrum, duration, and duty cycle;
     Sound propagation loss from source to animal, as well as, 
reflection and refraction;
     Received sound exposure measured using well-defined 
metrics;
     Specific hearing;
     Exposure duration; and
     Masking effects of background and ambient noise.
    To estimate exposures sufficient to be considered injury or 
significantly disrupt behavior by affecting the ability of an 
individual animal to grow (e.g., feeding and energetics), survive 
(e.g., behavioral reactions leading to injury or death, such as 
stranding), reproduce (e.g., mating behaviors), and/or degrade habitat 
quality resulting in abandonment or avoidance of those areas, 
dosimeters were attached to the virtual animals during the simulation 
process. Propagation and received impulse, SEL, and peak pressure are a 
function of depth, as well as range, depending on the location of an 
animal in the simulation space.
    A detailed discussion of the computational process for the 
modeling, which ultimately generates two outcomes--the zones of 
influence (ZOIs) and marine mammal exposures, is presented in the 
Navy's IHA application.
    Severity of an effect often is related to the distance between the 
sound source and a marine mammal and is influenced by source 
characteristics (Richardson and Malme 1995). For SSTC, ZOIs were 
estimated for the different charge weights, charge depths, water 
depths, and seasons using the REFMS model as described previously. 
These ZOIs for SSTC underwater detonations by training event are shown 
in Table 4 and conceptually illustrated in Figure 6-5 in the Navy's IHA 
application.
    For single detonations, the ZOIs were calculated using the range 
associated with the onset of TTS based on the Navy REFMS model 
predictions.
    For Multiple Successive Explosive events (i.e., sequential 
detonations) ZOI calculation was based on the range to non-TTS behavior 
disruption. Calculating the zones of influence in terms of total SEL, 
1/3-octave bands SEL, impulse, and peak pressure for sequential (10 sec 
timed) and multiple controlled detonations (>30 minutes) were slightly 
different than the single detonations. For the sequential detonations, 
ZOI calculations considered spatial and temporal distribution of the 
detonations, as well as the effective accumulation of the resultant 
acoustic energy. To calculate the ZOI, sequential detonations were 
modeled such that explosion SEL were summed incoherently to predict 
zones while peak pressure was not.

                         Table 4--Maximum ZOIs for Underwater Detonation Events at SSTC
----------------------------------------------------------------------------------------------------------------
                                                                          Maximum ZOI (yards)
                                                     -----------------------------------------------------------
                                                                TTS                   Injury           Mortality
  Underwater detonation training                     -----------------------------------------------------------
              event                     Season *                   182 dB re               205 dB re
                                                                       1       13.0 psi-       1       30.5 psi-
                                                        23 psi    [mu]Pa\2\-      ms      [mu]Pa\2\-      ms
                                                                       s                       s
----------------------------------------------------------------------------------------------------------------
Shock wave action generator        Warm.............          60          20           0           0           0
 (SWAG).
                                   Cold.............          40          20           0           0           0

[[Page 64287]]

 
Shock wave action generator        Warm.............          60          20           0           0           0
 (SWAG).
                                   Cold.............          40          20           0           0           0
Mine Counter Measure.............  Warm.............      ** 470         300         360          80          80
                                   Cold.............         430         340         160          80          80
Floating Mine....................  Warm.............         240         160          80          40          20
                                   Cold.............         260         180          80          40          20
Dive Platoon.....................  Warm.............         210         330          80          90          50
                                   Cold.............         220         370          90          90          50
Unmanned Underwater Vehicle......  Warm.............         440         280         360          80          80
                                   Cold.............         400         320         150          80          80
Marine Mammal Systems............  Warm.............         380         420         360         140          90
                                   Cold.............         450      ** 470         170         140          90
Marine Mammal Systems............  Warm.............         400         330         360         100          90
                                   Cold.............         400         370         170         100          90
Mine Neutralization..............  Warm.............         330         330          80          90          50
                                   Cold.............         360         370          90          90          50
Surf Zone Training and Evaluation  Warm.............      ** 470         300         160          80          80
                                   Cold.............         450         340         160          80          80
Unmanned Underwater Vehicle        Warm.............         400         280          80          60          50
 Neutralization.
                                   Cold.............         400         320          90          60          50
Airborne Mine Neutralization       Warm.............         220         170          80          40          40
 System.
                                   Cold.............         230         180          80          40          40
Qualification/Certification......  Warm.............      ** 470         330         140         100          80
                                   Cold.............         330         370         140         100          80
Qualification/Certification......  Warm.............         430         330         300          90          90
                                   Cold.............      ** 470         360         170          90          90
Naval Special Warfare Demolition   Warm.............         360         240         160          80          40
 Training.
                                   Cold.............         360         250         160          80          40
Naval Special Warfare Demolition   Warm.............         400         280          80          60          50
 Training.
                                   Cold.............         400         320          90          60          50
Navy Special Warfare SEAL          Warm.............         360         240         160          80          40
 Delivery Vehicle.
                                   Cold.............         360         250         160          80          40
----------------------------------------------------------------------------------------------------------------
* Warm: November-April; cold: May-October.
** Indicates event types with maximum ZOI as compared to all underwater detonation events.

    In summary, all ZOI radii were strongly influenced by charge size 
and placement in the water column, and only slightly by the environment 
variables.

Very Shallow Water (VSW) Underwater Detonations Live-Fire Tests ZOI 
Determination

    Measurements of the propagated pressures during single-charge 
underwater detonation exercises in VSW at SSTC (and San Clemente 
Island) were conducted in 2002 as part of a study to evaluate existing 
underwater explosive propagation models for application to VSW 
conditions (unpublished, Naval Special Warfare Center/Anteon 
Corporation 2005, cited in the Navy's SSTC IHA Application 2010). The 
direct measurements made in those tests provided an in-place 
characterization of pressure propagation for the training exercises as 
they are actually conducted at the SSTC. During the tests, 2 and 15 lbs 
charges of NEW explosives were detonated in 6 and 15 feet of water with 
charges laying on the bottom or two feet off the bottom at SSTC and San 
Clemente Island. At SSTC, swell conditions precluded detonations at the 
6-foot depth. Peak-pressures (unfiltered) and energies--between 100 Hz 
and 41 kHz--in 1/3-octave bands of highest energies from each 
detonation were measured in three locations relative to the charges: 
(1) 5-10 feet seaward of the charge, (2) 280-540 feet seaward, and (3) 
at about 1,000 feet seaward. Underwater detonations of small 2 lb 
charges at SSTC were measured at a ``near range'' location within feet 
of the charge and at a ``single far range'' of 525 feet from the charge 
(unpublished, Naval Special Warfare Center/Anteon Corporation 2005, 
cited in the Navy's SSTC IHA Application 2010). In the tests, the 
position of single charges--on and 2 feet off the bottom--affected the 
propagated peak-pressures. Off-bottom charges produced consistently 
greater peak-pressures than on-bottom charges as measured at about 200, 
500, and 1,000 feet distances. Off-bottom 15 lb charges in 15 feet of 
water produced between 43-67% greater peak-pressures than on-bottom 
charges. Greater differences were found when detonations occurred in 
extremely shallow depths of 6 feet at San Clemente Island (unpublished, 
Naval Special Warfare Center/Anteon Corporation 2005, cited in the 
Navy's SSTC IHA Application 2010). Generally, measurements during 
single-charge exercises produced empirical data that were predicted by 
the propagation models. At about 1,000 feet seaward, peak-pressure 
varied from 11-17 pounds psi at different depths, and energies between 
100 Hz and 41 kHz in the 1/3-octave bands of highest energies varied 
from about 175-186 dB re 1 [mu]Pa\2\-s at different depths. From the 
measurements, it was determined that the range at which the criterion 
for onset-TTS would be expected to occur in small odontocetes matched 
the range predicted by a conservative model of propagation that assumed 
a boundary-less medium and equal sound velocity at all depths in the 
range--i.e., an ``iso-

[[Page 64288]]

velocity'' model. Bottom and water-column conditions also influence 
pressure-wave propagation and dissipation of blast residues. In 
comparison, predictions made by the Navy's REFMS model (see above) were 
found to be unstable across the distances considered under the 
conditions of VSW with bottom or near bottom charge placement, 
reflective bottom, and a non-refractive water column (i.e., equal sound 
velocity at all depths). The source of instability in the REFMS 
predictions is most likely due to the nature of the VSW zone wherein 
the ratio of depth to range is very small--a known problem for the 
REFMS' predictive ray-tracing. Therefore, the determination of ZOIs 
within the VSW zones was based on the empirical propagation data and 
iso-velocity model predictions discussed above for charge-weights of 20 
lbs or less of NEW explosive on the bottom and for charge-weights of 
3.6 lbs or less off the bottom. For SSTC this range was determined to 
be a 1,200-foot (400-yard) radius out from the site of the detonation 
with the shoreward half of the implied circle being truncated by the 
shoreline and extremely shallow water immediately off shore.

Assessing ELCAS Pile Driving and Removal Impacts

    Noise associated with ELCAS training includes loud impulsive sounds 
derived from driving piles into the soft sandy substrate of the SSTC 
waters to temporarily support a causeway of linked pontoons. Two 
hammer-based methods will be used to install/remove ELCAS piles: Impact 
pile driving for installation and vibratory driving for removal. The 
impact hammer is a large metal ram attached to a crane. A vertical 
support holds the pile in place and the ram is dropped or forced 
downward. The energy is then transferred to the pile which is driven 
into the seabed. The ram is typically lifted by a diesel power source.
    The methodology for analyzing potential impacts from ELCAS events 
is similar to that of analyzing explosives. The ELCAS analysis includes 
two steps used to calculate potential exposures:
     Estimate the zone of influence for Level A injurious and 
Level B behavioral exposures for both impact pile driving and vibratory 
pile removal using the practical spreading loss equation (CALTRANS 
2009).
     Estimate the number of species exposed using species 
density estimates and estimated zones of influence.
    The practical spreading loss equation is typically used to estimate 
the attenuation of underwater sound over distance. The formula for this 
propagation loss can be expressed as:

TL = F * log (D1/D2)

Where:

TL = transmission loss (the sound pressure level at distance D1 
minus the sound pressure level at distance D2 from the source, in 
dBrms re 1[mu]Pa)
F = attenuation constant
D1 = distance at which the targeted transmission loss occurs
D2 = distance from which the transmission loss is calculated

    The attenuation constant (F) is a site-specific factor based on 
several conditions, including water depth, pile type, pile length, 
substrate type, and other factors. Measurements conducted by the 
California Department of Transportation (CADOT) and other consultants 
(Greeneridge Science) indicate that the attenuation constant (F) can 
vary from 5 to 30. Small-diameter steel H-type piles have been found to 
have high F values in the range of 20 to 30 near the pile (i.e., 
between 30-60 feet) (CALTRANS 2009). In the absence of empirically 
measured values at SSTC, NMFS and the Navy worked to set the F value 
for SSTC to be on the low (conservative, and more predictive) end of 
the small-diameter steel piles at F = 15, to indicate that the 
spreading loss is between the spherical (F = 20) and cylindrical (F = 
10).
    Actual noise source levels of ELCAS pile driving at SSTC depend on 
the type of hammer used, the size and material of the pile, and the 
substrate the piles are being driven into. Using known equipment, 
installation procedures, and applying certain constants derived from 
other west coast measured pile driving, predicted underwater sound 
levels from ELCAS pile driving can be calculated. The ELCAS uses 24-
inch diameter hollow steel piles, installed using a diesel impact 
hammer to drive the piles into the sandy on-shore and near-shore 
substrate at SSTC. For a dock repair project in Rodeo, California in 
San Francisco Bay, underwater sound pressure level (SPL) for a 24-inch 
steel pipe pile driven with a diesel impact hammer in less than 15 ft 
of water depth was measured at 189 dBrms re 1[mu]Pa from 
approximately 33 ft (11 yards) away. SPL for the same type and size 
pile also driven with a diesel impact hammer, but in greater than 36 ft 
of water depth, was measured to be 190 to 194 dBrms during 
the Amoco Wharf repair project in Carquinez Straits, Martinez, 
California (CADOT 2009). The areas where these projects were conducted 
have a silty sand bottom with an underlying hard clay layer, which 
because of the extra effort required to drive into clay, would make 
these measured pile driving sound levels louder (more conservative) 
than they would if driving into SSTC's sandy substrate. Given the local 
bathymetry and smooth sloping sandy bottom at SSTC, ELCAS piles will 
generally be driven in water depths of 36 ft or less.
    Therefore, for the purposes of the Navy's SSTC ELCAS analysis, both 
the Rodeo repair project (189 dBrms) and the low end of the 
measured values of the Amoco Wharf repair projects (190 
dBrms) are considered to be reasonably representative of 
sound levels that would be expected during ELCAS pile driving at SSTC. 
For hollow steel piles of similar size as those proposed for the ELCAS 
(<24-in diameter) used in Washington State and California pile driving 
projects, the broadband frequency range of underwater sound was 
measured between 50 Hz to 10.5 kHz with highest energy at frequencies 
<1 to 3 kHz (CALTRANS 2009). Although frequencies over 10.5 kHz are 
likely present during these pile driving projects, they are generally 
not typically measured since field data has shown a decrease in SPL to 
less than 120 dB at frequencies greater than 10.5 kHz (Laughlin 2005; 
2007). It is anticipated that ELCAS pile driving would generate a 
similar sound spectra.
    For ELCAS training events, using an estimated SPL measurement of 
190 dBrms re 1 [mu]Pa at 11 yards as described above, the 
circular ZOIs surrounding a 24-inch steel diesel-driven ELCAS pile can 
be estimated via the practical spreading loss equation to have radii 
of:
     11 yards for Level A injurious harassment for pinnipeds 
(190 dBrms);
     46 yards for Level A injurious harassment for cetaceans 
(180 dBrms), and
     1,094 yards for the Level B behavioral harassment (160 
dBrms).
    It should be noted that ELCAS pier construction starts with piles 
being driven near the shore and extends offshore. Near the shore, the 
area of influence would be a semi-circle and towards the end of the 
ELCAS (approximately 1,200 feet or 400 yards from the shore) would be a 
full circle. The above calculated area of influence conservatively 
assumes that all ELCAS piles are driven offshore at SSTC, producing a 
circular zone of influence, and discounts the limited propagation from 
piles driven closer to shore.
    Noise levels derived from piles removed via vibratory extractor are 
different than those driven with an impact hammer. Steel pilings and a 
vibratory driver were used for pile driving at the Port of Oakland 
(CALTRANS 2009). Underwater SPLs during this project for a 24-inch 
steel

[[Page 64289]]

pile in 36 ft of water depth at a distance of 11 yards (33 feet) from 
the source was field measured to be 160 dBrms. The area 
where this project was conducted (Oakland) has a harder substrate, 
which because of the extra effort required to drive and remove the 
pile, would make these measured pile driving sound levels louder (more 
conservative) than they would if driving and removing into and from 
SSTC's sandy substrate. Conservatively using this SPL measurement for 
SSTC and F = 15, the ZOIs for a 24-inch steel pile removed via a 
vibratory extractor out to different received SPLs can be estimated via 
the practical spreading loss equation to be:
     < 1 yard for Level A injurious harassment for pinnipeds 
(190 dBrms);
     One (1) yard for Level A injurious harassment for 
cetaceans (180 dBrms), and
     5,076 yards for the Level B behavioral harassment (120 
dBrms).
    As discussed above, the above calculated area of influence 
conservatively assumes that all ELCAS piles are driven and subsequently 
removed offshore at SSTC, producing a circular zone of influence.

Proposed Mitigation Measures

    In order to issue an incidental take authorization under Section 
101(a)(5)(D) of the MMPA, NMFS must set 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, and on the availability of such species 
or stock for taking for certain subsistence uses.
    For the Navy's proposed SSTC training activities, the Navy worked 
with NMFS and proposed the following mitigation measures to minimize 
the potential impacts to marine mammals in the project vicinity as a 
result of the underwater detonation and ELCAS pile driving/removal 
events.

Mitigation for Underwater Detonations in Very Shallow Water (0-24 Feet)

    The following mitigation procedures formalize practices that are 
currently in effect at SSTC for detonations conducted in the VSW zone.
    1. Easily visible anchored floats would be positioned on a 1,200-
foot (400-yard) radius of a roughly semi-circular zone (the shoreward 
half being bounded by shoreline and immediate off-shore water) around 
the detonation location for small explosive exercises at the SSTC. 
These mark the outer limits of the safety zone. The 1,200 foot or 400 
yard radius is the safety zone for VSW as determined from empirical 
measurements as discussed earlier.
    2. For each VSW underwater detonation event, a safety-boat with a 
minimum of one observer would be launched at least 30 minutes prior to 
detonation and moves through the area around the detonation site. The 
task of the safety observer is to exclude humans from coming into the 
area and to augment a shore observer's visual search of the mitigation 
zone for marine mammals. The safety-boat observer is in constant radio 
communication with the exercise coordinator and shore observer 
discussed below.
    3. A shore-based observer will also be deployed for VSW detonations 
in addition to boat based observers. The shore observer will indicate 
that the area is clear of marine mammals after 10 or more minutes of 
continuous observation with no marine mammals having been seen in the 
mitigation zone (1,200 feet or 400 yards) or moving toward it.
    4. At least 10 minutes prior to the planned initiation of the 
detonation event-sequence, the shore observer, on an elevated on-shore 
position, begins a continuous visual search with binoculars of the 
mitigation zone. At this time, the safety-boat observer informs the 
shore observer if any marine mammal has been seen in the safety zone 
and, together, both search the surface within and beyond the safety 
zone for marine mammals.
    5. The observers (boat and shore based) will indicate that the area 
is not clear any time a marine mammal is sited in the safety zone or 
moving toward it and, subsequently, indicate that the area is clear of 
marine mammals when the animal is out and moving away and no other 
marine mammals have been sited.
    6. Initiation of the detonation sequence would only begin on final 
receipt of an indication from the shore observer that the area is clear 
of marine mammals and will be postponed on receipt of an indication 
from that or any observer that the area is not clear of marine mammals.
    7. Following the detonation, visual monitoring of the safety zone 
continues for 30 minutes for the appearance of any marine mammal in the 
zone. Any marine mammal appearing in the area would be observed for 
signs of possible injury.
    8. Any marine mammal observed after an VSW underwater detonation 
either injured or exhibiting signs of distress would be reported to 
Navy environmental representatives from the regional Navy shore 
commander (Commander, Navy Region Southwest) and U.S. Pacific Fleet, 
Environmental Office, San Diego Detachment. Using Marine Mammal 
Stranding communication trees and contact procedures established for 
the Southern California Range Complex, the Navy will report these 
events to the Stranding Coordinator of NMFS' Southwest Regional Office. 
These voice or e-mail reports will contain the date and time of the 
sighting, location (or if precise latitude and longitude is not 
currently available, then the approximate location in reference to an 
established SSTC beach feature), species description (if known), and 
indication of the animals status.

Mitigation for Underwater Detonations in Shallow Water

    Modeling results for ZOIs discussed previously were used to develop 
mitigation zones applicable to the mitigation measures for underwater 
detonations in water between 24-72 feet at the SSTC. The ZOIs 
effectively represent the mitigation zone that would be established 
around each detonation point to prevent Level B harassment to marine 
mammals. While the ZOIs vary between the different types of underwater 
detonation training, the Navy is proposing to establish a 470-yard 
mitigation zone for the maximum zone of influence from all underwater 
detonations except Shock Wave Generator (SWAG) detonations conducted on 
the oceanside of SSTC (see Table 4). This large a mitigation zone is 
not necessary for any underwater detonations other than the Marine 
Mammal System operations (see Table 4), but it is proposed as a 
conservative (i.e., over protective) measure. SWAGs have smaller, more 
directional charges and therefore a small ZOI, so a smaller mitigation 
zone of 60 yards is proposed.
    The mitigation measures for underwater detonation events on the 
oceanside of SSTC (except for SWAG events) are listed as follows:
I. Underwater Detonation Mitigation (24-72 Feet) (All Except SWAG)
    1. A mitigation zone of 1,410 feet (470 yards) will be established 
around each underwater detonation point. This mitigation zone is based 
on the maximum range to onset-TTS (either 23 psi or 182 dB re 1 
[mu]Pa\2\-s).
    2. A minimum of two boats, including but not limited to small 
zodiacs and 11-meter Rigid Hulled Inflatable Boats (RHIB) will be 
deployed. One boat will act as an observer platform, while the other 
boat is typically the diver support boat.
    3. Two observers with binoculars on one small craft/boat will 
survey the

[[Page 64290]]

detonation area and the mitigation zone for marine mammals from at 
least 30 minutes prior to commencement of the scheduled explosive event 
and until at least 30 minutes after detonation.
    4. In addition to the dedicated observers, all divers and boat 
operators engaged in detonation events can potentially monitor the area 
immediately surrounding the point of detonation for marine mammals (and 
other protected species such as sea turtles).
    5. If a marine mammal is sighted within the 1,410-foot (470-yard) 
mitigation zone or moving towards it, underwater detonation events will 
be suspended until the marine mammal has voluntarily left the area and 
the area is clear of marine mammals for at least 30 minutes.
    6. Immediately following the detonation, visual monitoring for 
marine mammals within the mitigation zone will continue for 30 minutes. 
Any marine mammal observed after an underwater detonation either 
injured or exhibiting signs of distress will be reported to Navy 
environmental representatives from the regional Navy shore commander 
(Commander, Navy Region Southwest) and U.S. Pacific Fleet, 
Environmental Office, San Diego Detachment. Using Marine Mammal 
Stranding communication trees and contact procedures established for 
the Southern California Range Complex, the Navy will report these 
events to the Stranding Coordinator of NMFS' Southwest Regional Office. 
These voice or e-mail reports will contain the date and time of the 
sighting, location (or if precise latitude and longitude is not 
currently available, then the approximate location in reference to an 
established SSTC beach feature), species description (if known), and 
indication of the animal's status.
II. Underwater Detonation Mitigation (SWAG Events Only)
    A modified set of mitigation measures would be implemented for SWAG 
detonations, which involve much smaller charges of 0.03 lbs NEW.
    1. A mitigation zone of 180 feet or 60 yards will be established 
around each SWAG detonation site.
    2. A minimum of two boats, including but not limited to small 
zodiacs and 11-meter Rigid Hulled Inflatable Boats (RHIB) will be 
deployed. One boat will act as an observer platform, while the other 
boat is typically the diver support boat.
    3. Two observers with binoculars on one small craft/boat will 
survey the detonation area and the mitigation zone for marine mammals 
(and other protected species such as sea turtles) from at least 10 
minutes prior to commencement of the scheduled explosive event and 
until at least 10 minutes after detonation.
    4. In addition to the dedicated observers, all divers and boat 
operators engaged in detonation events can potentially monitor the area 
immediately surrounding the point of detonation for marine mammals.
    5. Divers and personnel in support boats would monitor for marine 
mammals out to the 180 feet (60 yards) mitigation zone for 10 minutes 
prior to any detonation.
    6. After the detonation, visual monitoring for marine mammals would 
continue for 10 minutes. Any marine mammal observed after an underwater 
SWAG detonation either injured or exhibiting signs of distress will be 
reported to Navy environmental representatives from the regional Navy 
shore commander (Commander, Navy Region Southwest) and U.S. Pacific 
Fleet, Environmental Office, San Diego Detachment. Using Marine Mammal 
Stranding communication trees and contact procedures established for 
the Southern California Range Complex, the Navy will report these 
events to the Stranding Coordinator of NMFS' Southwest Regional Office. 
These voice or e-mail reports will contain the date and time of the 
sighting, location (or if precise latitude and longitude is not 
currently available, then the approximate location in reference to an 
established SSTC beach feature), species description (if known), and 
indication of the animal's status.

Mitigation for ELCAS Training at SSTC

    NMFS worked with the Navy and proposes the below mitigation 
procedures for ELCAS pile driving and removal events along the 
oceanside Boat Lanes at the SSTC for marine mammal species.
    1. Mitigation Zone: A mitigation zone will be established at 150 
feet (50 yards) from ELCAS pile driving and pile removal events. This 
mitigation zone is based on the predicted range to Level A harassment 
(180 dBrms) for cetaceans, and is being applied 
conservatively to both cetaceans and pinnipeds.
    2. Monitoring will be conducted within the 150 foot or 50 yard 
mitigation zone surrounding ELCAS pile driving and removal events for 
the presence of marine mammals before, during, and after pile driving 
and removal events.
    3. If marine mammals are found within the 150-foot (50-yard) 
mitigation zone, pile removal events will be halted until the marine 
mammals have voluntarily left the mitigation zone.
    4. Monitoring for marine mammals will take place concurrent with 
pile removal events and 30 minutes prior to pile driving and removal 
commencement. A minimum of one trained observer will be placed on 
shore, on the ELCAS, or in a boat at the best vantage point(s) 
practicable to monitor for marine mammals.
    5. Monitoring observer(s) will implement shut-down/delay procedures 
by calling for shut-down to the hammer operator when marine mammals are 
sighted within the mitigation zone.
    6. Soft Start--ELCAS pile driving would implement a soft start as 
part of normal construction procedures. The pile driver increases 
impact strength as resistance goes up. At first, the pile driver piston 
drops a few inches. As resistance goes up, the pile driver piston will 
drop from a higher distance thus providing more impact due to gravity. 
This will allow marine mammals in the project area to vacate or begin 
vacating the area minimizing potential harassment.
    7. ELCAS Acoustic Monitoring: The Navy proposes, under the 
associated SSTC marine mammal monitoring plan, to conduct underwater 
acoustic propagation monitoring during the first available ELCAS 
deployment at the SSTC under this Incidental Harassment Authorization 
application. This acoustic monitoring would provide empirical field 
data on ELCAS pile driving and removal underwater source levels, and 
propagation specific to ELCAS training at the SSTC. These results will 
be used to either confirm or refine the Navy's exposure predictions 
(source level, F value, exposures) described earlier.
    NMFS has carefully evaluated these proposed mitigation measures. 
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, 
practicality of implementation.
    Based on our evaluation of these proposed measures, NMFS has 
preliminarily determined that the proposed mitigation measures provide 
the means of effecting the least practicable adverse impacts on marine 
mammal species or stocks and their

[[Page 64291]]

habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance.

Proposed Monitoring and Reporting Measures

Proposed Monitoring Measures

    In order to issue an ITA for an activity, Section 101(a)(5)(D) 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 IHAs 
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. The proposed monitoring and 
reporting measures for the Navy's proposed SSTC training exercises are 
provided below.
    The SSTC Monitoring Program, proposed by the Navy as part of its 
IHA application, is focused on mitigation based monitoring and 
presented more fully in Appendix A of the Navy's IHA application. Main 
monitoring techniques include use of civilian scientists as marine 
mammal observers during a sub-set of SSTC underwater detonation events 
to validate the Navy's pre and post event mitigation effectiveness, and 
observe marine mammal reaction, or lack of reaction to SSTC training 
events. Also, as stated in the Proposed Mitigation section, the Navy 
proposes to conduct an acoustic monitoring project during the first 
field deployment of the ELCAS to the SSTC. The objective of this 
project under the SSTC Monitoring Plan would be to empirically measure 
site-specific ELCAS underwater sound propagation at SSTC, with the goal 
of refining future marine mammal exposure estimates.
    Monitoring methods proposed for the SSTC training exercise include:
     Marine Mammal Observers (MMO) at SSTC underwater 
detonations.
     ELCAS underwater propagation monitoring project.
     Leverage aerial monitoring from other Navy-funded 
monitoring.
I. Marine Mammal Observer at a Sub-Set of SSTC Underwater Detonations
    Civilian scientists acting as MMOs will be used to observe a sub-
set of the SSTC underwater detonation events. The goal of MMOs is two-
fold. One, to validate the suite of SSTC specific mitigation measures 
applicable to a sub-set of SSTC training events, and to observe marine 
mammal behavior in the vicinity of SSTC training events.
    MMOs will be field-experienced observers that are either Navy 
biologists or contracted marine biologists. These civilian MMOs will be 
placed either alongside existing Navy SSTC operators during a sub-set 
of training events, or on a separate small boat viewing platform. Use 
of MMOs will verify Navy mitigation efforts within the SSTC, offer an 
opportunity for more detailed species identification, provide an 
opportunity to bring animal protection awareness to Navy personnel at 
SSTC, and provide the opportunity for an experienced biologist to 
collect data on marine mammal behavior. Data collected by the MMOs is 
anticipated to integrate with a Navy-wide effort to assess Navy 
training impacts on marine mammals (DoN 2009). Events selected for MMO 
participation will be an appropriate fit in terms of security, safety, 
logistics, and compatibility with Navy underwater detonation training.
    MMOs will collect the same data currently being collected for more 
elaborate offshore ship-based observations including but not limited 
to:
    (1) Location of sighting;
    (2) Species;
    (3) Number of individuals;
    (4) Number of calves present;
    (5) Duration of sighting;
    (6) Behavior of marine animals sighted;
    (7) Direction of travel;
    (8) Environmental information associated with sighting event 
including Beaufort sea state, wave height, swell direction, wind 
direction, wind speed, glare, percentage of glare, percentage of cloud 
cover; and
    (9) When in relation to Navy training did the sighting occur 
[before, during or after the detonation(s)].
    The MMOs will not be part of the Navy's formal reporting chain of 
command during their data collection efforts. Exceptions will be made 
if a marine mammal is observed by the MMO within the SSTC specific 
mitigation zones the Navy has formally proposed to the NMFS. The MMO 
will inform any Navy operator of the sighting so that appropriate 
action may be taken by the Navy trainees.
II. Leverage From Existing Navy-Funded Marine Mammal Research
    The Navy will report results obtained annually from the Southern 
California Range Complex Monitoring Plan (DoN 2009) for areas pertinent 
to the SSTC. In the Navy's 2011 Letter of Authorization renewal 
application and subsequent Year 3 Southern California Monitoring Plan 
(DoN 2010), a new study area for aerial visual survey was created. This 
area would start at the shoreline of the oceanside Boat Lanes at SSTC 
and extend seaward to approximately 10 nm offshore. The goal of these 
aerial visual surveys is to document marine mammal occurrence within a 
given sub-area off Southern California. Significant surface area can be 
covered by a survey aircraft flying at 800 to 1,000 feet for 
approximately five hours. The use of both airplanes and helicopters as 
aerial platforms will be considered for the survey area off SSTC. Both 
aircraft type, in particular the helicopter, provide excellent 
platforms for documenting marine mammal behaviors and through digital 
photography and digital video.

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 both to compliance as well as ensuring that the most value is 
obtained from the required monitoring.
I. General Notification of Injured or Dead Marine Mammals
    Navy personnel will ensure that NMFS (regional stranding 
coordinator) is notified immediately (or as soon as clearance 
procedures allow) if an injured or dead marine mammal is found during 
or shortly after, and in the vicinity of, any Navy training exercises 
involving underwater detonations or pile driving. 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).
II. Final Report
    The Navy will submit a final report to the Office of Protected 
Resources, NMFS, no later than 90 days after the expiration of the LOA. 
The report will, at a minimum, includes the following marine mammal 
sighting information:
    (1) Location of sighting;
    (2) Species;
    (3) Number of individuals;
    (4) Number of calves present;
    (5) Duration of sighting;
    (6) Behavior of marine animals sighted;
    (7) Direction of travel;
    (8) Environmental information associated with sighting event 
including Beaufort sea state, wave height, swell direction, wind 
direction, wind speed, glare, percentage of glare, percentage of cloud 
cover; and

[[Page 64292]]

    (9) When in relation to Navy training did the sighting occur 
[before, during or after the detonation(s)].
    In addition, the Navy would provide the information described below 
for all of its underwater detonation events and ELCAS events under the 
IHA, if issued. The information includes: (1) Total number of each type 
of underwater detonation events (of these listed in Table 2 of this 
document) conducted at the SSTC, and (2) total number of piles driven 
and extracted during the ELCAS exercise.
    The Navy will submit to NMFS a draft report as described above and 
will respond to NMFS comments within 3 months of receipt. The report 
will be considered final after the Navy has addressed NMFS' comments, 
or three months after the submittal of the draft if NMFS does not 
comment by then.

Estimated Take by Incidental Harassment

Estimated Marine Mammal Exposures From SSTC Underwater Detonations

    The quantitative exposure modeling methodology estimated numbers of 
individuals exposed to the effects of underwater detonations exceeding 
the thresholds used, as if no mitigation measures were employed.
    All estimated exposures are seasonal averages (mean) plus one 
standard deviation using \1/2\ of the yearly training tempo to 
represent each season. Taking this approach was an effort to be 
conservative (i.e., allow for an overestimate of exposure) when 
estimating exposures typical of training during a single year.
    Table 5 shows number of annual predicted exposures by species for 
all underwater detonation training within the SSTC. As stated 
previously, only events with sequential detonations were examined for 
non-TTS behavior disruption.

               Table 5--SSTC Modeled Estimates of Species Exposed to Underwater Detonations Without Implementation of Mitigation Measures
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    Annual Marine Mammal Exposure (All Sources)
                                                                                       --------------------------------------------------------------------
                                                                                         Level B Behavior     Level B TTS          Level A       Mortality
                                                                                            (Multiple     ------------------------------------- -----------
                                                                                            Successive
                              Species                                                    Explosive Events
                                                                                              Only)           182 dB re 1        205 dB re 1     30.5 psi-
                                                                                       -------------------   [mu]Pa\2\-s/23    [mu]Pa\2\-s/13.0      ms
                                                                                           177 dB re 1            psi               psi-ms
                                                                                              [mu]Pa
----------------------------------------------------------------------------------------------------------------------------------------------- -----------
Gray Whale
    Warm...........................................................  .................  .................  .................  .................
    Cold...........................................................                  0                  0                  0                  0
Bottlenose Dolphin
    Warm...........................................................                 30                 43                  0                  0
    Cold...........................................................                 40                 55                  0                  0
California Sea Lion
    Warm...........................................................                  4                  4                  0                  0
    Cold...........................................................                 40                 51                  0                  0
Harbor Seal
    Warm...........................................................                  0                  0                  0                  0
    Cold...........................................................                  0                  0                  0                  0
                                                                    ------------------------------------------------------------------------------------
        Total Annual Exposures.....................................                114                153                  0                  0
--------------------------------------------------------------------------------------------------------------------------------------------------------

    In summary, for all underwater detonations, the Navy's impact model 
predicted that no mortality and/or Level A harassment (injury) would 
occur to marine mammal species and stocks within the proposed action 
area.
    For non-sequential (i.e., single detonation) training events, the 
Navy's impact model predicted a total of 153 annual exposures that 
could result in Level B harassment (TTS), which include 98 annual 
exposures to bottlenose dolphins and 55 annual exposures to California 
sea lions.
    For sequential (Multiple Successive Explosive events) training 
events, the Navy's impact model predicted a total of 114 annual 
exposures that could result in Level B behavioral harassment, which 
include 70 annual exposures to bottlenose dolphins and 44 annual 
exposures to California sea lions.

Estimated Marine Mammal Exposures From ELCAS Pile Driving and Removal

I. Pile Driving
    Using the marine mammal densities presented in the Navy's IHA 
application, the number of animals exposed to annual Level B harassment 
from ELCAS pile driving can be estimated:
    Exposures per event = ZOI x (warm season marine mammal density + 
cold season marine mammal density), with ZOI = [pi] x R\2\, where R is 
the radius of the ZOI.
    Area of Exposures per year = (Exposures per event x number of days 
of pile driving)/year.
    Pile driving is estimated to occur 10 days per ELCAS training 
event, with up to four training exercises being conducted per year (40 
days per year).
    Based on the assessments conducted, using the methodology discussed 
previously, and without consideration of current mitigation measures, 
ELCAS pile driving is predicted to result in no Level A Harassments to 
any marine mammal (received SPL of 190 dBrms for pinnipeds 
and 180 dBrms re 1 [mu]Pa for cetacean, respectively) but 40 
bottlenose dolphins and 20 California sea lions by Level B behavioral 
harassment (Table 6).
II. Pile Removal
    Using the marine mammal densities presented in the Navy's IHA 
application, the number of animals exposed to annual Level B harassment 
from ELCAS pile driving can be estimated:
Exposures per event = ZOI x (warm season marine mammal density + cold 
season marine mammal density), with ZOI = [pi] x R\2\, where R is the 
radius of the ZOI.
Area of Exposures per year = (Exposures per event x number of days of 
pile removal)/year.


[[Page 64293]]


    Pile removal is estimated to occur 3 days per ELCAS training event, 
with up to four training exercises being conducted per year (12 days 
per year).
    Based on the assessments conducted, using the methodology discussed 
previously, and without consideration of current mitigation measures, 
ELCAS pile driving is predicted to result in no Level A Harassments to 
any marine mammal (received SPL of 190 dBrms for pinnipeds 
and 180 dBrms re 1 [mu]Pa for cetacean, respectively) but in 
Level B behavioral harassment of 168 bottlenose dolphins, 102 
California sea lions, 12 harbor seals, and 6 gray whales (Table 6).

 Table 6--Exposure Estimates From ELCAS Pile Driving and Removal Prior to Implementation of Mitigation Measures
----------------------------------------------------------------------------------------------------------------
                                                            Annual Marine Mammal Exposure (All Sources)
                                                 ---------------------------------------------------------------
                                                      Level B         Level B
                     Species                      Behavior  (Non-    Behavior         Level A         Level A
                                                   Impulse)  120  (Impulse)  120    (Cetacean)      (Pinniped)
                                                    dB rms re 1     dB rms re 1    120 dB rms re   120 dB rms re
                                                      [mu]Pa          [mu]Pa         1 [mu]Pa        1 [mu]Pa
----------------------------------------------------------------------------------------------------------------
Gray Whale:
    Installation................................             N/A               0               0               0
    Removal.....................................               6             N/A               0               0
Bottlenose Dolphin:
    Installation................................             N/A              40               0               0
    Removal.....................................             168             N/A               0               0
California Sea Lion:
    Installation................................             N/A              20               0               0
    Removal.....................................             102             N/A               0               0
Harbor Seal:
    Installation................................             N/A               0               0               0
    Removal.....................................              12             N/A               0               0
                                                 ---------------------------------------------------------------
        Total Annual Exposures..................             288              60               0               0
----------------------------------------------------------------------------------------------------------------

Potential Impacts to Marine Mammal Habitat

    The proposed training activities at SSTC will not result in any 
permanent impact on habitats used by marine mammals, and potentially 
short-term to minimum impact to the food sources such as forage fish. 
There are no known haul-out sites, foraging hotspots, or other ocean 
bottom structures of significant biological importance to harbor seals, 
California sea lions, or bottlenose dolphins within SSTC. Therefore, 
the main impact associated with the proposed activity will be 
temporarily elevated noise levels and the associated direct effects on 
marine mammals, as discussed previously.
    The primary source of effects to marine mammal habitat is exposures 
resulting from underwater detonation training and ELCAS pile driving 
and removal training events. Other sources that may affect marine 
mammal habitat include changes in transiting vessels, vessel strike, 
turbidity, and introduction of fuel, debris, ordnance, and chemical 
residues. However, each of these components was addressed in the SSTC 
Environmental Impact Statement (EIS) and it is the Navy's assertion 
that there would be no likely impacts to marine mammal habitats from 
these training events.
    The most likely impact to marine mammal habitat occurs from 
underwater detonation and pile driving and removal effects on likely 
marine mammal prey (i.e., fish) within SSTC.
    There are currently no well-established thresholds for estimating 
effects to fish from explosives other than mortality models. Fish that 
are located in the water column, in proximity to the source of 
detonation could be injured, killed, or disturbed by the impulsive 
sound and could leave the area temporarily. Continental Shelf Inc. 
(2004) summarized a few studies conducted to determine effects 
associated with removal of offshore structures (e.g., oil rigs) in the 
Gulf of Mexico. Their findings revealed that at very close range, 
underwater explosions are lethal to most fish species regardless of 
size, shape, or internal anatomy. In most situations, cause of death in 
fish has been massive organ and tissue damage and internal bleeding. At 
longer range, species with gas-filled swimbladders (e.g., snapper, cod, 
and striped bass) are more susceptible than those without swimbladders 
(e.g., flounders, eels).
    Studies also suggest that larger fish are generally less 
susceptible to death or injury than small fish. Moreover, elongated 
forms that are round in cross section are less at risk than deep-bodied 
forms. Orientation of fish relative to the shock wave may also affect 
the extent of injury. Open water pelagic fish (e.g., mackerel) seem to 
be less affected than reef fishes. The results of most studies are 
dependent upon specific biological, environmental, explosive, and data 
recording factors.
    The huge variation in fish populations, including numbers, species, 
sizes, and orientation and range from the detonation point, makes it 
very difficult to accurately predict mortalities at any specific site 
of detonation. All underwater detonations are of small scale (under 29 
lbs NEW), and the proposed training exercises would be conducted in 
several areas within the large SSTC Study Area over the seasons during 
the year. Most fish species experience a large number of natural 
mortalities, especially during early life-stages, and any small level 
of mortality caused by the SSTC training exercises involving explosives 
will likely be insignificant to the population as a whole.
    Therefore, potential impacts to marine mammal food resources within 
the SSTC are expected to be minimal given both the very geographic and 
spatially limited scope of most Navy at-sea activities including 
underwater detonations, and the high biological productivity of these 
resources. No short or long term effects to marine mammal food 
resources from Navy activities are anticipated within the SSTC Study 
Area.

[[Page 64294]]

Subsistence Harvest of Marine Mammals

    NMFS has preliminarily determined that the Navy's proposed training 
activities at the SSTC would not have an unmitigable adverse impact on 
the availability of the affected species or stocks for subsistence use 
since there are no such uses in the specified area.

Negligible Impact and Small Numbers Analysis and 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 
considers 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.), as well as 
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 training exercises at SSTC action area. Some 
of the noises that would be generated as a result of the proposed 
underwater detonation and ELCAS pile driving activities, are high 
intensity. However, the explosives that the Navy plans to use in the 
proposed SSTC action area are all small detonators under 29 lbs NEW, 
which result in relatively small ZOIs. In addition, the locations where 
the proposed training activities are planned are shallow water areas 
which would effectively contain the spreading of explosive energy 
within the bottom boundary. Taking the above into account, along with 
the fact that NMFS anticipates no mortalities and injuries to result 
from the action, the fact that there are no specific areas of 
reproductive importance for marine mammals recognized within the SSTC 
area, the sections discussed below, and dependent upon the 
implementation of the proposed mitigation measures, NMFS has determined 
that Navy training exercises utilizing underwater detonations and ELCAS 
pile driving and removal will have a negligible impact on the affected 
marine mammal species and stocks present in the SSTC 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 SSTC training activities was provided 
earlier in this document and is analyzed in more detail below.

Behavioral Harassment

    As discussed earlier, the Navy's proposed SSTC training activities 
would use small underwater explosives with maximum NEW of 29 lbs 16 
events per year in areas of small ZOIs that would mostly eliminate the 
likelihood of mortality and injury to marine mammals. In addition, 
these detonation events are widely dispersed in several designated 
sites within the SSTC 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 vicinity of 
SSTC Study Area and the implementation of monitoring and mitigation 
measures. Moreover, NMFS does not expect animals to experience repeat 
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 of Level B behavioral harassment 
(i.e., 177 dB re 1 [mu]Pa\2\-s), 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 or recruitment 
or survival.
    In addition, ELCAS events planned at SSTC would employ relatively 
small hammers for impact and vibratory pile driving and removal, with 
extremely small safety radii for 180 dB (46 yards for impact pile 
driving and 1 yard for vibratory pile removal) and 190 dB (11 yards for 
impact pile driving and < 1 yard for vibratory pile removal) zones. 
Therefore, it is highly unlikely that any marine mammals would occur in 
such close proximity to the pile driving site.

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 SEL. The threshold for the 
onset of TTS for detonations is a dual criteria: 182 dB re 1 [mu]Pa\2\-
s or 23 psi, which might be received at distances from 20-470 yards 
from the centers of detonation based on the types of 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 exposures of almost an hour in duration or up to 
SEL at 217 dB re 1 [mu]Pa\2\-s, 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 animals' 
sensitivity is expected to recover fully in minutes to hours based on 
the fact that the proposed underwater detonations are small in scale 
and isolated. Therefore, NMFS expects that TTS would not affect annual 
rates of recruitment or survival.

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.

[[Page 64295]]

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 
detonation and pile driving are brief and the majority of most animals' 
vocalizations would not be masked. Although impulse noises such as 
those from underwater explosives and impact pile driving tend to decay 
at distance, and thus become non-impulse, give the area of extremely 
shallow water (which effectively attenuates low frequency sound of 
these impulses) and the small NEW of explosives, the SPLs at these 
distances are expected to be barely above ambient level. Therefore, 
masking effects from underwater detonation 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 modeling for take estimates show that no marine mammal would be 
taken by Level A harassment (injury, PTS included) or mortality due to 
the low power of the underwater detonation and the small ZOIs.
    Based on these assessments, NMFS determined that approximately 6 
gray whales, 221 California sea lions, 12 harbor seals, and 323 
bottlenose dolphins could be affected by Level B harassment (TTS and 
sub-TTS) as a result of the proposed SSTC training activities. These 
numbers represent approximately 0.02%, 0.93%, and 0.06% of gray whales 
(eastern North Pacific stock), California sea lions (U.S. Stock), and 
harbor seal (California stock), respectively in the vicinity of the 
proposed SSTC Study Area (calculation based on NMFS 2009 U.S. Pacific 
Marine Mammal Stock Assessment; Carretta et al. 2010). However, the 
estimated take of California coastal stock of bottlenose dolphin 
indicates that the entire population (100%) could be affected as the 
result of the Navy's proposed SSTC training activities. Given the fact 
that these annual takes are spread over the entire year, and that on 
average each individual bottlenose dolphin would be exposed once to 
received levels that could cause Level B harassment in a year, NMFS 
does not believe such adverse effects would be biologically significant 
as to affect the growth, survivor, and reproduction of this stock.
    Additionally, as discussed previously, the aforementioned take 
estimates do not account for the implementation of mitigation measures. 
With the implementation of mitigation and monitoring measures, NMFS 
expects that the takes would be reduced further. Coupled with the fact 
that these impacts will likely not occur in areas and times critical to 
reproduction, NMFS has preliminarily determined that the total taking 
incidental to the Navy's proposed SSTC training activities would have a 
negligible impact on the marine mammal species and stocks present in 
the SSTC Study Area.

Endangered Species Act (ESA)

    No marine mammal species are listed as endangered or threatened 
under the ESA with confirmed or possible occurrence in the study area. 
Therefore, section 7 consultation under the ESA for NMFS's proposed 
issuance of an MMPA authorization is not warranted.

National Environmental Policy Act (NEPA)

    The Navy is preparing an Environmental Impact Statement (EIS) for 
the proposed SSTC training activities. A draft EIS was released in July 
2010 and it is available at http://www.silverstrandtrainingcomplexeis.com/EIS.aspx/. NMFS is a cooperating 
agency (as defined by the Council on Environmental Quality (40 CFR 
1501.6)) in the preparation of the EIS. NMFS has reviewed the Draft EIS 
and will be working with the Navy on the Final EIS (FEIS).
    NMFS intends to adopt the Navy's FEIS, if adequate and appropriate, 
and we believe that the Navy's FEIS will allow NMFS to meet its 
responsibilities under NEPA for the issuance of the IHA for training 
activities in the SSTC Study Area. If the Navy's FEIS is not adequate, 
NMFS will supplement the existing analysis and documents to ensure that 
we comply with NEPA prior to the issuance of the IHA.

    Dated: October 14, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2010-26286 Filed 10-18-10; 8:45 am]
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