[Federal Register Volume 78, Number 79 (Wednesday, April 24, 2013)]
[Notices]
[Pages 24161-24184]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-09618]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XC533
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 a complete 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) 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, eight species of
marine mammals during the specified activity.
DATES: Comments and information must be received no later than May 24,
2013.
ADDRESSES: Comments on the application should be addressed to P.
Michael Payne, Chief, Permits and Conservation Division, Office of
Protected Resources, National Marine Fisheries Service, 1315 East-West
Highway, Silver Spring, MD 20910-3225. The mailbox address for
providing email comments is [email protected]. NMFS is not
responsible for email comments sent to addresses other than the one
provided here. Comments sent via email, including all attachments, must
not exceed a 10-megabyte file size.
Instructions: All comments received are a part of the public record
and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information
(for example, name, address, etc.) voluntarily submitted by the
commenter may be publicly accessible. Do not submit Confidential
Business Information or otherwise sensitive or protected information.
A copy of the application may be obtained by 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: Michelle Magliocca, Office of
Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
direct 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
[[Page 24162]]
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) (Public Law
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 December 19, 2012, 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. Underwater
detonations and pile driving/removal during training events at the SSTC
may rise to the level of harassment as defined under the MMPA. The Navy
is currently operating under an IHA for training activities at the SSTC
covering the period from July 18, 2012, through July 17, 2013.
Description of the Specific Activity
The Navy has conducted a review of its continuing and proposed
training conducted at the SSTC to determine whether there is a
potential for harassment of marine mammals. Underwater detonation
training and pile driving, as described below, may result in the
incidental take of marine mammals from elevated levels of sound. Other
training events conducted at the SSTC, which are not expected to rise
to the level of harassment, are described in the SSTC Final
Environmental Impact Statement (http://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications).
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 units conduct most of the
underwater detonation training at the SSTC as part of their training in
the detection, avoidance, and neutralization of mines. Tables 1-3 and
2-1 in the Navy's LOA application describe in detail the types of
underwater detonation training events conducted at the SSTC. Below is a
basic description of some underwater detonation procedures that
typically apply to underwater training events at the SSTC, with the
exception of the Unmanned Underwater Vehicle Neutralization and
Airborne Mine Neutralization System.
Prior to getting underway, all EOD and NSW personnel
conduct a detailed safety and procedure briefing to familiarize
everyone with the goals, objectives, and safety requirements (including
mitigation zones) applicable to the particular training event.
For safety reasons, and in accordance with Navy
directives, given the training nature of many of these events,
underwater detonations only occur during daylight and are only
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).
EOD or NSW personnel can be transported to the planned
detonation site via small boat or helicopter depending on the training
event. Small boats can include 7-m Rigid Hull Inflatable Boats (RHIB),
zodiacs, or other similar craft as available to the particular unit.
Once on site, the applicable mitigation zone is
established and visual survey commences for 30 minutes. Divers enter
the water to conduct the training objective which could include
searching for a training object such as a simulated mine or mine-like
shape.
For the detonation part of the training, the explosive
charge and associate charge initiating device are taken to the
detonation point. The explosives used are military forms of C-4. In
order to detonate C-4, a fusing and initiating device is required.
Following a particular underwater detonation, additional
personnel in the support boats (or helicopter) keep watch within the
mitigation zone for 30 minutes.
Concurrent with the post-detonation survey, divers return
to the detonation site to confirm the explosives detonated correctly
and retrieve any residual material (pieces of wire, tape, large
fragments, etc.).
The Navy uses both time-delay and positive control to initiate
underwater detonations, depending on the training event and objectives.
The time-delay method uses a Time-delay Firing Device (TDFD) and the
positive control method most commonly uses a Remote Firing Device
(RFD). TDFDs are the simplest, safest, least expensive, most
operationally acceptable method of initiating an underwater detonation.
TDFDs are preferred due to their light weight, low magnetic signature
(in cases of mines sensitive to magnetic fields), and reduced risk of
accidental detonation from nearby radios or other electronics. TDFDs
allow sufficient time for EOD personnel to swim outside of the
detonation plume radius and human safety buffer zone after the timer is
set. For a surface detonation training event involving a helicopter or
a boat, the minimum time-delay that is reasonable for EOD divers to
make their way to safety is about 10 minutes. For underwater detonation
training events at depth using small boats, the time-delay can be
minimized to 5 minutes; however, this requires the instructors to
handle initiation of the detonation and therefore results in decreased
training value for students. The Navy considers it critical that EOD
and NSW platoons qualify annually with necessary time-delay
certification, maintain proficiency, and train to face real-world
scenarios that require use of TDFDs.
While positive control devices do allow for instantaneous
detonation of a
[[Page 24163]]
charge and are used for some SSTC training events, RFDs are the less-
preferred method to initiate an underwater detonation. Current Navy
RFDs use a radio signal to remotely detonate a charge. By using
electronic positive control devices such as the RFD, additional
electronic signals and metal from the receiver and wiring is
unnecessarily introduced into the operating environment. Underwater
detonation events need to be kept as simple and streamlined as
possible, especially when diver safety is considered. In an open ocean
environment, universal use of RFDs would greatly increase the risk of
misfire due to component failure, and put unnecessary stress on all
needed connections and devices (adding 600-1,000 feet of firing wire;
building/deploying an improvised, bulky, floating system for the RFD
receiver; and adding another 180 feet of detonating cord plus 10 feet
of other material).
Pile Driving
Installation and removal of Elevated Causeway System (ELCAS)
support piles may also result in the harassment of marine mammals. The
ELCAS is a modular pre-fabricated causeway pier that links offshore
amphibious supply ships with associated lighterage (i.e., small cargo
boats and barges). Offloaded vehicles and supplies can be driven on the
causeway to and from shore.
During ELCAS training events, 24-inch wide hollow steel piles would
be driven into the sand in the surf zone with an impact hammer. About
101 piles would be driven into the beach and surf zone with a diesel
impact hammer over the course of about 10 days, 24-hours per day (i.e.,
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 drops
a few inches. As resistance goes up, the pile driver piston drops from
a higher distance, providing more impact due to gravity. The pile
driver can take 5 to 7 minutes to reach full impact strength. As
chapters of piles are installed, causeway platforms are then hoisted
and secured onto the piles with hydraulic jacks and cranes. At the end
of training, the ELCAS piles would be removed with a vibratory
extractor. Removal takes about 15 minutes per pile over a period of
around 3 days. ELCAS training may occur along both the ocean side
(SSTC-North boat and beach lanes) and with the designated training lane
within Bravo beach on the bayside of SSTC. Up to four ELCAS training/
installation events may occur during the year.
Dates and Duration of Proposed Activities
The Navy's proposed activities would occur between July 2013 and
July 2014. Most underwater detonation training events include one or
two detonations. Table 2-1 in the Navy's LOA application shows the 19
different types and number of training events per year in the SSTC.
Pile installation and removal would occur over an approximate 13 day
period, up to four times per year. NMFS is proposing to issue a 1-year
IHA that may be superseded if we issue a Letter of Authorization under
regulations for the Navy's Hawaii-Southern California Training and
Testing (HSTT) (which would include the SSTC) prior to expiration of
the IHA.
Location of Proposed Activities
The SSTC (Figure 1-1 of the Navy's IHA application) is located in
and adjacent to San Diego Bay, south of Coronado, California and north
of Imperial Beach, California. The complex is composed of ocean and bay
training lanes, adjacent beach training areas, ocean anchorages, and
inland training areas. To facilitate range management and scheduling,
the SSTC is divided into numerous training sub-areas.
The surfside training lanes of the SSTC are located in the Silver
Strand Littoral Cell, which is an exposed, open subtidal area of the
Pacific Ocean extending from south of the international border to the
Zuniga Jetty at San Diego Bay for over 17 miles of coastal reach. The
Silver Strand Littoral Cell is a coastal eddy system that dominates
local ocean movement and generally moves from south to north with
periodic reversals. Surface water temperatures generally are highest
from June through September and lowest from November through February.
Historical temperatures in the study area range from 52 to 74 degrees
Fahrenheit near the surface and from 49 to 61 degrees Fahrenheit near
the bottom. Water temperatures near the beach tend to be more uniform
throughout the water column due to turbulent mixing and shallower
depth. The bathymetry off the surfside training lanes is relatively
evenly sloped, with a predominantly soft sandy bottom mixed with minor
amounts of mud, hard-shale bedrock, and small cobble-boulder fields.
The area does not have underwater canyons or significant upwelling
conditions. Flora and fauna in the region of the SSTC is dominated by
coastal surf zone and some coastal pelagic zone species. In the summer
of 2011, the Navy funded a new benthic habitat survey to reassess
benthic habitat and bottom conditions with results shown in Figure 2-1
of the Navy LOA application. A second follow-up benthic habitat survey
was performed in the late summer and fall of 2012 to cover areas
between SSTC-North and SSTC-South, as well as areas further offshore to
the 120-foot contour.
Description of Marine Mammals in the Area of the Specified Activity
Four marine mammal species may inhabit or regularly transit the
SSTC area: California sea lion (Zalophus californianus), Pacific harbor
seal (Phoca vitulina richardsii), California coastal stock of
bottlenose dolphin (Tursiops truncatus), and gray whale (Eschrichtius
robustus). Following the incident of common dolphin mortalities that
resulted from the use of TDFDs during a training exercise in 2012, the
Navy and NMFS reassessed the species distribution in the SSTC study
area and included four additional dolphin species: long-beaked common
dolphin (Delphinus capensis), short-beaked common dolphin (D. delphis),
Pacific white-sided dolphin (Lagenorhynchus obliquidens), and Risso's
dolphin (Grampus griseus). These four dolphin species are less frequent
visitors, but have been sighted in the vicinity of the SSTC training
area.
Navy-funded surveys in the SSTC in late 2012 and 2013 have
documented the sporadic presence of long-beaked common dolphins near
some parts of the SSTC. There is no documented NMFS sighting data for
short-beaked common dolphin, Pacific white-sided dolphin, or Risso's
dolphin, or other anecdotal information currently available as to
likely presence within the very near-shore, shallow waters associated
with the SSTC boat lanes. Therefore, the Navy included these species in
their analysis in the rare event that they move through the SSTC boat
lanes. None of the species above are listed as threatened or endangered
under the Endangered Species Act (ESA). Further information on these
species can also be found in the NMFS Stock Assessment Reports (SAR)
(http://www.nmfs.noaa.gov/pr/species/mammals/).
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
[[Page 24164]]
(more than 95 percent) 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 percent (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 identify 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) (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 percent of their time
at sea during the non-breeding season (cold-water months) and pups
spent an average of 67 percent 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 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 296,750 (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). Based on the most recent harbor seal counts (19,608 in May-
July 2009; NMFS unpublished data) and the Harvey and Goley (2011)
correction factor, the harbor seal population in California is
estimated to number 30,196.
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
[[Page 24165]]
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. 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 percent 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 surf
perches and croakers (Norris and Prescott 1961; Walker 1981; Schwartz
et al. 1992; Hanson and Defran 1993), and also consume squid (Schwartz
et al. 1992). The coastal stock of bottlenose dolphin utilizes a
limited number of fish prey species with up to 74 percent being various
species of surfperch or croakers, a group of non-migratory year-round
coastal inhabitants (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 percent of their
time spent in travel and dive-travel mode and only 5 percent 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 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 percent
of dolphins encountered lack identifiable dorsal fin marks (Defran and
Weller 1999). If 35 percent 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
[[Page 24166]]
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 whales that might infrequently transit through the SSTC would not
be expected to forage, and would likely be present for less than 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 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 percent
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).
Long-Beaked Common Dolphin, California Stock
Long-beaked common dolphins are found year-round in the waters off
California (Carretta et al. 2000; Bearzi 2005; DoN 2009, 2010). The
distribution and abundance of long-beaked common dolphins appears to be
variable based on inter-annual and seasonal time scales (Dohl et al.
1986; Heyning and Perrin 1994; Barlow 1995; Forney et al. 1995; Forney
and Barlow 2007). As oceanographic conditions change, long-beaked
common dolphins may move between Mexican and U.S. waters, and therefore
a multi-year average abundance estimate is the most appropriate for
management within the U.S. waters (Carretta et al. 2010). California
waters represent the northern limit for this stock and animal's likely
movement between U.S. and Mexican waters. No information on trends in
abundance is available for this stock because of high inter-annual
variability in line-transect abundance estimates (Carretta et al.
2010). Heyning and Perrin (1994) detected changes in the proportion of
short-beaked to long-beaked common dolphins stranding along the
California coast, with the short-beaked common dolphin stranding more
frequently prior to the 1982-83 El Ni[ntilde]o (which increased water
temperatures off California), and the long-beaked common dolphin more
frequently observed for several years afterwards. Thus, it appears that
both relative and absolute abundance of these species off California
may change with varying oceanographic conditions (Carretta et al.
2010). Common dolphin distributions may be related to bathymetry (Hui
1979). Long-beaked common dolphins are usually found within 50 nautical
miles (nm) (92.5 km) of shore with significantly more occurrence near
canyons, escarpments, and slopes (Heyning and Perrin 1994; Barlow et
al. 1997; Bearzi 2005, 2006). Group size ranges from less than a dozen
to several thousand individuals (Barlow and Forney 2007; Barlow et al.
2010).
Recent anecdotal accounts from Navy Explosive Ordnance Disposal
(EOD) divers remark on periodic sightings of large dolphin pods within
the more seaward portions of the SSTC that are likely comprised of
long-beaked common dolphin. During SSTC Navy-funded marine mammal
monitoring conducted over 2 days in November 2012, there were confirmed
sightings of long-beaked common dolphin pods in the outer portions of
the SSTC in about 75 feet of water. Unlike the large congregated
schools common to this species, the long-beaked common dolphins seen in
November were in widely dispersed small sub-groups with one to five
dolphins per group. Individuals and small groups were seen chasing bait
fish to the surface and foraging. The dolphins were observed over a
one-hour period and eventually left the SSTC heading seaward.
Sparse information is available on the life history of long-beaked
common dolphins, however, some information is provided for short-beaked
common dolphins which may also apply to long-beaked dolphins. North
Pacific short-beaked common dolphin females and males reach sexual
maturity at roughly 8 and 10 years, respectively (Ferrero and Walker
1995). Peak calving season for common dolphins in the eastern North
Pacific may be spring and early summer (Forney 1994). Barlow (2010)
reported average group size for long-beaked common dolphins within a
Southern California-specific stratum as 195 individuals from a 2008
survey along the U.S. West Coast. The geometric mean abundance estimate
in NMFS' annual stock assessment for the entire California stock of
long-beaked common dolphins, based on two ship surveys conducted in
2005 and 2008, is 27,046 (CV = 0.59) (Forney 2007; Barlow 2010;
Carretta et al. 2010). Using a more stratified approach, Barlow et al.
(2010) estimated abundance within a Southern California-specific strata
of 16,480 (CV = 0.41) long-beaked common dolphins based on analysis of
pooled sighting data from 1991-2008. Long-beaked common dolphins are
not listed under the ESA, and are not considered a strategic stock
under the MMPA.
Pacific White-sided Dolphin, California/Oregon/Washington Stock
While Pacific white-sided dolphins could potentially occur year-
round in Southern California, surveys suggest a seasonal north-south
movement in the eastern North Pacific, with animals found primarily off
California during the colder water months and shifting
[[Page 24167]]
northward into Oregon and Washington as water temperatures increase
during late spring and summer (Green et al. 1992, 1993; Forney 1994;
Forney and Barlow 2007; Barlow 2010). Salvadeo et al. (2010) propose
that increased global warming may increase a northward shift in Pacific
white-sided dolphins. The Pacific white-sided dolphin is most common in
waters over the continental shelf and slope, however, sighting records
and captures in pelagic driftnets indicate that this species also
occurs in oceanic waters well beyond the shelf and slope (Leatherwood
et al. 1984; DoN 2009, 2010). Soldevilla et al. (2010a) reported the
possibility of two distinct eco-types of Pacific white-sided dolphins
occurring in Southern California based on passive acoustic detection of
two distinct echolocation click patterns. No population trends have
been observed in California or adjacent waters. Barlow (2010) reported
average group size for Pacific white-sided dolphins within a Southern
California-specific stratum as 17 from a 2008 survey along the U.S.
West Coast. The size of the entire California/Oregon/Washington Stock
is estimated to be 26,930 (CV = 0.28) individuals (Forney 2007, Barlow,
2010). Using a more stratified approach, Barlow et al. (2010) estimated
abundance within a Southern California-specific strata of 1,914 (CV =
0.39) Pacific white-sided dolphins based on analysis of pooled sighting
data from 1991-2008. Pacific white-sided dolphins are not listed under
the ESA, and are not considered a strategic stock under the MMPA.
Risso's Dolphin, California/Oregon/Washington Stock
Off the U.S. West coast, Risso's dolphins are commonly seen on the
shelf off Southern California and in slope and offshore waters of
California, Oregon and Washington (Soldevilla et al. 2010b; Carretta et
al. 2010). Animals found off California during the colder water months
are thought to shift northward into Oregon and Washington as water
temperatures increase in late spring and summer (Green et al. 1992).
The southern end of this population's range is not well documented, but
previous surveys have shown a conspicuous 500 nm distributional gap
between these animals and Risso's dolphins sighted south of Baja
California and in the Gulf of California (Mangels and Gerrodette 1994).
Thus this population appears distinct from animals found in the eastern
tropical Pacific and the Gulf of California (Carretta et al. 2010). As
oceanographic conditions vary, Risso's dolphins may spend time outside
the U.S. Exclusive Economic Zone. Barlow (2010) reported average group
size for Risso's dolphins within a Southern California-specific stratum
as 23 from a 2008 survey along the U.S. West Coast. The size of the
California/Oregon/Washington Stock is estimated to be 6,272 (CV = 0.30)
individuals (Forney 2007; Barlow 2010; Carretta et al. 2010). Using a
more stratified approach, Barlow et al. (2010) estimated abundance
within a Southern California-specific strata of 3,974 (CV = 0.39)
Risso's dolphins based on analysis of pooled sighting data from 1991-
2008. Risso's dolphins are not listed under the ESA, and are not
considered a strategic stock under the MMPA.
Short-Beaked Common Dolphin, California/Oregon/Washington Stock
Short-beaked common dolphins are the most abundant cetacean off
California, and are widely distributed between the coast and at least
300 nm distance from shore (Dohl et al. 1981; Forney et al. 1995;
Barlow 2010; Carretta et al. 2010). Along the U.S. West Coast, portions
of the short-beaked common dolphins' distribution overlap with that of
the long-beaked common dolphin. The northward extent of short-beaked
common dolphin distribution appears to vary inter-annually and with
changing oceanographic conditions (Forney and Barlow 1998). Barlow
(2010) reported average group size for short-beaked common dolphins
within a Southern California-specific stratum as 122 from a 2008 survey
along the U.S. West Coast. The size of the California/Oregon/Washington
Stock is estimated to be 411,211 (CV = 0.21) individuals (Carretta et
al. 2010). Using a more stratified approach, Barlow et al. (2010)
estimated abundance within a Southern California-specific strata of
152,000 (CV = 0.17) short-beaked common dolphins based on analysis of
pooled sighting data from 1991-2008. Short-beaked common dolphins are
not listed under the ESA, and are not considered a strategic stock
under the MMPA.
Potential Effects on Marine Mammals
Anticipated impacts resulting from the Navy's proposed SSTC
training activities include disturbance from underwater detonation
events and pile driving from ELCAS training 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.
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 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 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, including
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
[[Page 24168]]
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 species with mid- and
high-frequency echolocation sounds. 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 haul-outs 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 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, from 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 the Incidental Harassment
Authorization application, all marine mammals within the calculated
radius for 1 percent probability of onset of extensive lung injury
(i.e., onset of mortality) were counted as lethal exposures. The range
at which 1 percent probability of onset of extensive lung hemorrhage is
expected to occur is greater than the ranges at which 50 percent to 100
percent 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 were 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 highly 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
[[Page 24169]]
depend 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, and
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 [mu]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 [mu]Pa and Bar, also are
used.
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
[mu]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 [mu]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).
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 [mu]Pa) or higher and pinnipeds exposed to 190 dBrms or
higher are considered to have been taken by Level A (i.e., injurious)
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 30.5 psi-ms
lung injury (1 (positive
percent impulse).
probability of
mortality).
Level A Harassment (Injury)..... Slight lung 13.0 psi-ms
injury; or. (positive
impulse).
50 percent of 205 dB re 1
marine mammals [mu]Pa\2\-s
would experience (full spectrum
ear drum rupture; energy).
and 30 percent
exposed sustain
PTS.
Level B Harassment.............. TTS (dual 23 psi (peak
criteria). 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 [mu]Pa.
repeated exposure
to received
levels that cause
TTS.
Cetacean only: PTS 180 dBrms re 1
caused by [mu]Pa.
repeated exposure
to received
levels that cause
TTS.
Level B Behavioral Harassment... Cetacean only: 160 dBrms re 1
Impulse noise; [mu]Pa.
Behavioral
modification of
animals.
[[Page 24170]]
Pinniped only: Non- 190 dBrms re 1
impulse noise; [mu]Pa.
Behavioral
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 detonates. 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 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.
[[Page 24171]]
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 the SSTC
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum ZOI (yards)
-------------------------------------------------------------------------------
TTS Injury Mortality
Underwater detonation training event Season\*\ -------------------------------------------------------------------------------
182 dB re 1 205 dB re 1
23 psi [mu]Pa\2\-s 13.0 psi-ms [mu]Pa\2\-s 30.5 psi-ms
--------------------------------------------------------------------------------------------------------------------------------------------------------
Shock wave action generator (SWAG) (San Warm....................... 60 20 0 0 0
Diego Bay--Echo sub-area) 0.033 NEW (74/
yr).
Cold....................... 40 20 0 0 0
Shock wave action generator (SWAG) (SSTC-- Warm....................... 60 20 0 0 0
North and South oceanside) 0.033 NEW (16/
yr).
Cold....................... 40 20 0 0 0
Mine Counter Measure < 20 lbs NEW (29/yr).. Warm....................... 470 300 360 80 80
Cold....................... 450 340 160 80 80
Floating Mine < 5 lbs NEW (53/yr).......... Warm....................... 240 160 80 40 20
Cold....................... 260 180 80 40 20
Dive Platoon < 3.5 lbs NEW (sequential) (8/ Warm....................... 210 330 80 90 50
yr).
Cold....................... 220 370 90 90 50
Unmanned Underwater Vehicle <15 lbs NEW (4/ Warm....................... 440 280 360 80 80
yr).
Cold....................... 400 320 150 80 80
Marine Mammal Systems < 29 lbs NEW Warm....................... 380 420 360 140 90
(sequential) (8/yr).
Cold....................... 450 470 170 140 90
Marine Mammal Systems < 29 lbs NEW (8/yr).. Warm....................... 400 330 360 100 90
Cold....................... 490 370 170 100 90
Mine Neutralization < 3.5 lbs NEW Warm....................... 210 330 80 90 50
(sequential) (4/yr).
Cold....................... 230 370 90 90 50
[[Page 24172]]
Surf Zone Training and Evaluation < 20 lbs Warm....................... 470 300 160 80 80
NEW (2/yr).
Cold....................... 450 340 160 80 80
Unmanned Underwater Vehicle Neutralization Warm....................... 220 180 80 60 50
< 3.6 lbs NEW (sequential) (4/yr).
Cold....................... 230 180 90 60 50
Airborne Mine Neutralization System < 3.5 Warm....................... 220 170 80 40 40
lbs NEW (10/yr).
Cold....................... 230 180 80 40 40
Qualification/Certification < 13.8 lbs NEW Warm....................... 330 330 140 100 80
(sequential) (8/yr).
Cold....................... 360 370 140 100 80
Qualification/Certification < 25.5 lbs NEW Warm....................... 420 330 300 90 90
(4/yr).
Cold....................... 470 360 170 90 90
Naval Special Warfare Demolition Training < Warm....................... 360 240 160 80 40
10 lbs NEW (4/yr).
Cold....................... 360 250 160 80 40
Naval Special Warfare Demolition Training < Warm....................... 220 180 80 60 50
3.6 lbs NEW (4/yr).
Cold....................... 230 180 90 60 50
Navy Special Warfare SEAL Delivery Vehicle Warm....................... 360 240 160 80 40
< 10 lbs NEW (40/yr).
Cold....................... 360 250 160 80 40
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Warm: November-April; cold: May-October.
In summary, all ZOI radii were strongly influenced by charge size
and placement in the water column, and only slightly by the environment
variables. Detailed information on ZOI determination for very shallow
water is provided in section 6 of the Navy's LOA application.
The anticipated impacts from marine mammal exposure to explosive
detonations and pile-driving remain unchanged from the IHA issued to
the Navy in 2012 (77 FR 43238, July 24, 2012).
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.
The take estimates provided later in this document represent the
maximum expected number of takes and do not account for mitigation
measures. The Navy proposes the following mitigation measures to reduce
potential impacts to marine mammals:
Mitigation Zones
The Navy used the ZOI modeling results (discussed in Chapter 6 of
their IHA application) to develop mitigation zones for underwater
detonations in water >24 feet and Shock Wave Generator (SWAG) training
events. While the ZOIs vary between the different types of underwater
detonation training, the Navy is proposing to establish an expanded 700
yard mitigation zone for all positive control (RFD) underwater
detonations conducted on the oceanside of the SSTC, a 700-1,500 yard
mitigation zone around all time-delay (TDFD) underwater detonations
conducted on the oceanside of the SSTC, and a 60 yard mitigation zone
around SWAG training events conducted on the oceanside and bayside of
the SSTC. Details on how the mitigation zones were derived are provided
in section 11 of the Navy's IHA application. These mitigation zones are
expected to reduce or eliminate Level B harassment to marine mammals.
The Navy also proposes a 50 yard mitigation zone during ELCAS pile
driving and removal. In summary, the proposed mitigation zones are as
follows for the three broad sets of training events:
Very shallow water (<24 feet) underwater detonation--The Navy would
use a 700 yard mitigation zone for positive control events, and 700-
1,500 yard mitigation zone for TDFD events depending on charge weight
and delay time. The positive control mitigation zone is based on the
maximum range of onset TTS as predicted by the iso-velocity analysis of
empirically measured very shallow water detonations <20 lbs NEW (450-
470 yards) plus a buffer that brings the final zone to 700 yards.
Shallow water (24 feet) underwater detonation--The Navy
would use a 700 yard mitigation zone for positive control events, and
700-1,500 yard mitigation zone for TDFD events depending on charge
weight and delay time. The positive control mitigation zone is based on
the maximum range to onset TTS predicted using the Navy's REFMS model
(490 yards) plus a buffer that brings the final zone to 700 yards.
ELCAS pile driving and removal--The Navy would use a 50 yard
mitigation zone based on the maximum range estimated to the Level A
harassment criteria for cetaceans (180 dB).
Proposed Mitigation Measures for Underwater Detonations in Very Shallow
Water (VSW, water depth <24 ft)
Positive Control
1. Underwater detonations using positive control (remote firing
devices) will only be conducted during daylight.
2. Easily visible anchored floats will be positioned on 700 yard
radius of a roughly semi-circular zone (the
[[Page 24173]]
shoreward half being bounded by shoreline and immediate offshore water)
around the detonation location for small explosive exercises at the
SSTC. These mark the outer limits of the mitigation zone.
3. For each VSW underwater detonation event, a safety-boat with a
minimum of one observer is launched 30 or more 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.
4. 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 or moving toward it.
5. 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 zone and,
together, both search the surface within and beyond the mitigation zone
for marine mammals.
6. The observers (boat and shore based) will indicate that the area
is not clear any time a marine mammal is sighted in the mitigation 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.
7. Initiation of the detonation sequence will 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 any observer that the area is not clear of marine mammals.
8. Following the detonation, visual monitoring of the mitigation
zone continues for 30 minutes for the appearance of any marine mammal
in the zone. Any marine mammal appearing in the area will be observed
for signs of possible injury.
9. Any marine mammal observed after a VSW underwater detonation
either injured or exhibiting signs of distress will be reported via
operational chain of command to Navy environmental representatives from
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 email 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.
Time-Delay Firing Devices
1. Underwater detonations using timed delay devices would only be
conducted during daylight.
2. Time-delays longer than 10 minutes would not be used. The
initiation of the device will not start until the mitigation area below
is clear for a full 30 minutes prior to initiation of the timer.
3. A mitigation zone would be established around each underwater
detonation location as indicated in Table 7 (1,000, 1,400 yards, or
1,500) based on charge weight and length of time delay used.
4. VSW ranges 1,000 yds:
For each VSW underwater detonation event with a mitigation
zone of 1,000 yds, a safety boat with a minimum of one observer is
launched 30 or more minutes prior to detonation and moves through the
area around the detonation site at the seaward edge of the mitigation
zone. The task of the boat 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. To the best extent practical, boats will try to
maintain a 10 knot search speed.
A shore-based observer will also be deployed for VSW
detonations in addition to boat based observers. 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 zone and, together, both search the surface within
and beyond the mitigation zone for marine mammals. 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 or moving toward it.
5. VSW ranges >=1,400 yards:
A minimum of two boats and one shore-based observer would
be used to survey for marine mammals at mitigation ranges >=1,400
yards.
When conducting the surveys within a mitigation zone
>=1,400 yds, boats will position themselves near the mid-point of the
mitigation zone radius (but always outside the detonation plume radius/
human safety zone) and travel in a semi-circular pattern around the
detonation location surveying both the inner (toward detonation site)
and outer (away from detonation site) areas. When using two boats, each
boat will be positioned on opposite sides of the detonation location,
separated by 180 degrees. If using more than two boats, each boat will
be positioned equidistant from one another (120 degrees separation for
three boats, 90 degrees separation for four boats, etc.). If available,
aerial visual survey support from Navy helicopters can be utilized, so
long as it will not jeopardize safety of flight. Helicopters will
travel in a circular pattern around the detonation location.
6. A mitigation zone will be surveyed from 30 minutes prior to the
detonation and for 30 minutes after the detonation.
7. Other personnel besides boat observers can also maintain
situational awareness on the presence of marine mammals within the
mitigation zone to the best extent practical given dive safety
considerations.
Divers placing the charges on mines will observe the immediate
underwater area around a detonation site for marine mammals and report
sightings to surface observers.
8. If a marine mammal is sighted within an established 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.
9. Immediately following the detonation, visual monitoring for
affected marine mammals within the mitigation zone will continue for 30
minutes.
10. Any marine mammal observed after an underwater detonation
either injured or exhibiting signs of distress will be reported via
Navy operational chain of command to Navy environmental representatives
from U.S. Pacific Fleet, Environmental Office, San Diego Detachment.
Using Marine
[[Page 24174]]
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 email 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.
Proposed Mitigation and Monitoring Measures for Underwater Detonations
in Shallow Water (>24 Feet)
Positive Control (Except SWAG and Timed Detonations)
1. Underwater detonations using positive control devices would only
be conducted during daylight.
2. A mitigation zone of 700 yards would be established around each
underwater detonation point.
3. A minimum of two boats, including but not limited to small
zodiacs and 7-m Rigid Hulled Inflatable Boats (RHIB) would be deployed.
One boat would act as an observer platform, while the other boat is
typically the diver support boat.
4. Two observers with binoculars on one small craft/boat would
survey the 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.
5. 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.
6. Explosive detonations would cease if a marine mammal is visually
detected within the mitigation zone. Detonations may recommence if any
of the following conditions are met: (1) The animal is observed exiting
the mitigation zone, (2) the animal is thought to have exited the
mitigation zone based on its course and speed, or (3) the mitigation
zone has been clear from any additional sightings for a period of 30
minutes.
7. 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 via Navy
operational chain of command to Navy environmental representatives from
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 email 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 and Monitoring Measures for Underwater Detonations Using
Time-Delay (TDFD Detonations Only)
1. Underwater detonations using timed delay devices would only be
conducted during daylight.
2. Time-delays longer than 10 minutes would not be used. The
initiation of the device would not start until the mitigation area
below is clear for a full 30 minutes prior to initiation of the timer.
3. A mitigation zone would be established around each underwater
detonation location as indicated in Table 3 based on charge weight and
length of time-delay used. When conducting the surveys within a
mitigation zone (either 1,000 or >=1,400 yds), boats will position
themselves near the mid-point of the mitigation zone radius (but always
outside the detonation plume radius/human safety zone) and travel in a
circular pattern around the detonation location surveying both the
inner (toward detonation site) and outer (away from detonation site)
areas.
4. Shallow water TDFD detonations 1,000 yds:
A minimum of two boats would be used to survey for marine
mammals at mitigation ranges of 1,000 yds.
When using two boats, each boat would be positioned on
opposite sides of the detonation location, separated by 180 degrees.
Two observers in each of the boats will conduct continuous
visual survey of the mitigation zone for the entire duration of a
training event.
To the best extent practical, boats will try to maintain a
10 knot search speed. This search speed was added to ensure adequate
coverage of the buffer zone during observation periods. While weather
conditions and sea states may require slower speeds in some instances,
10 knots is a prudent, safe, and executable speed that will allow for
adequate surveillance. For a 1,000 yd radius buffer zone a boat
travelling at 10 knots and 500 yds away from the detonation point would
circle the detonation point 3.22 times during a 30 minute survey
period. By using two boats, 6.44 circles around the detonation point
would be completed in a 30 minute span.
5. Shallow water TDFD detonations >=1,400 yds:
A minimum of three boats or two boats and one helicopter
would be used to survey for marine mammals at mitigation ranges of
1,400 yds.
When using three (or more) boats, each boat would be
positioned equidistant from one another (120 degrees separation for
three boats, 90 degrees separation for four boats, etc.).
For a 1,400 yd radius mitigation zone, a 10 knot speed
results in 2.3 circles for each of the three boats, or nearly 7 circles
around the detonation point over a 30 minute span.
If available, aerial visual survey support from Navy
helicopters can be utilized, so long as it will not jeopardize safety
of flight.
Helicopters, if available, can be used in lieu of one of
the boat requirements. Navy helicopter pilots are trained to conduct
searches for relatively small objects in the water, such as a missing
person. A helicopter search pattern is dictated by standard Navy
protocols and accounts for multiple variables, such as the size and
shape of the search area, size of the object being searched for, and
local environmental conditions, among others.
6. A mitigation zone would be surveyed from 30 minutes prior to the
detonation and for 30 minutes after the detonation.
7. Other personnel besides boat observers can also maintain
situational awareness on the presence of marine mammals within the
mitigation zone to the best extent practical given dive safety
considerations.
Divers placing the charges on mines would observe the immediate
underwater area around a detonation site for marine mammals and report
sightings to surface observers.
8. If a marine mammal is sighted within an established 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.
9. Immediately following the detonation, visual monitoring for
affected marine mammals within the mitigation zone will continue for 30
minutes.
10. Any marine mammal observed after an underwater detonation
either
[[Page 24175]]
injured or exhibiting signs of distress will be reported via Navy
operational chain of command to Navy environmental representatives from
U.S. Pacific Fleet, Environmental Office, San Diego Detachment or Pearl
Harbor. Using Marine Mammal Stranding protocols and communication trees
established for the Southern California and Hawaii Range Complexes, the
Navy will report these events to the Stranding Coordinator of NMFS'
Southwest or Pacific Islands Regional Office. These voice or email
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.
(3) Proposed Mitigation and Monitoring Measures for Underwater SWAG
Detonations (SWAG Only)
A modified set of mitigation measures would be implemented for SWAG
detonations, which involve much smaller charges of 0.03 lbs NEW.
1. Underwater detonations using SWAG would only be conducted during
daylight.
2. A mitigation zone of 60 yards would be established around each
SWAG detonation site.
3. A minimum of two boats, including but not limited to small
zodiacs and 7-m Rigid Hulled Inflatable Boats (RHIB) would be deployed.
One boat would act as an observer platform, while the other boat is
typically the diver support boat.
4. Two observers with binoculars on one small craft\boat would
survey the detonation area and the mitigation zone for marine mammals
from at least 10 minutes prior to commencement of the scheduled
explosive event and until at least 10 minutes after detonation.
5. 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.
Divers and personnel in support boats would monitor for marine
mammals out to the 60 yard 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
detonation either injured or exhibiting signs of distress will be
reported via Navy operational chain of command to Navy environmental
representatives from 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 email 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.
Proposed Mitigation for ELCAS Training
Mitigation zone--A mitigation zone would be established at
50 yards from ELCAS pile driving and removal events. This mitigation
zone is based on the predicted range to Level A harassment for
cetaceans (180 dB) and would also be applied to pinnipeds.
Monitoring would be conducted within the 50 yard
mitigation zone for the presence of marine mammals during ELCAS pile
driving and removal events. Monitoring would begin 30 minutes before
any ELCAS pile driving or removal event, continue during pile driving
or removal events, and be conducted for 30 minutes after pile driving
or removal ends. A minimum of one trained observer would be placed on
shore, on the ELCAS, or in a boat at the best vantage point(s) to
monitor for marine mammals.
If a marine mammal is seen within the 50 yard mitigation
zone, pile removal events would be delayed or stopped until the animal
has voluntarily left the mitigation zone.
The observer(s) would implement shutdown and delay
procedures when applicable by notifying the hammer operator when a
marine mammal is seen within the mitigation zone.
Soft start-The Navy would implement a soft start for all
ELCAS pile driving. The pile driver would increase impact strength as
resistance goes up. The pile driver piston initially drops a few
inches, but as resistance increases, the pile driver piston drops from
a higher distance and has more impact. This would allow marine mammals
in the proposed action area to move away from the sound source before
the pile driver reaches full power.
Proposed Monitoring and Reporting
In order to issue an ITA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth, where applicable,
``requirements pertaining to the monitoring and reporting of such
taking.'' The MMPA implementing regulations at 50 CFR 216.104(a)(13)
indicate that requests for ITAs must include the suggested means of
accomplishing the necessary monitoring and reporting that will result
in increased knowledge of the species and of the level of taking or
impacts on populations of marine mammals that are expected to be
present in the proposed action area.
In addition to the mitigation monitoring described above, the Navy
also proposes to monitor a subset 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. The Navy also proposes to conduct an acoustic
monitoring project during the first field deployment of the ELCAS.
Monitoring a Subset of Underwater Detonations
Protected species observers would be placed either alongside
existing Navy SSTC operators during a subset of training events, or on
a separate small boat viewing platform. Use of protected species
observers would 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
the SSTC, and provide the opportunity for an experienced biologist to
collect data on marine mammal behavior. Events selected for protected
species observer participation would be an appropriate fit in terms of
security, safety, logistics, and compatibility with Navy underwater
detonation training. The Navy would attempt to monitor between 2 and 4
percent of their annual underwater detonations (6-12 detonations).
Protected species observers would collect the same data currently being
collected for more elaborate offshore ship-based observations,
including but not limited to:
Location of sighting;
Species;
Number of individuals;
Number of calves present;
Duration of sighting;
Behavior of marine mammals sighted;
Direction of travel;
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
Whether the sighting occurred before, during, or after a
detonation.
Protected species observers would not be part of the Navy's formal
reporting
[[Page 24176]]
chain of command during their data collection efforts. However,
exceptions would be made if a marine mammal is observed within the
proposed mitigation zone. Protected species observers would inform any
Navy operator of the sighting so that appropriate action may be taken.
ELCAS Underwater Propagation Monitoring
The Navy proposes to conduct an underwater acoustic propagation
monitoring project during the first available ELCAS deployment at the
SSTC. The acoustic monitoring would provide empirical field data on
actual ELCAS pile driving and removal underwater source levels, and
propagation specific to ELCAS training at the SSTC. These results would
be used to either confirm or refine the Navy's exposure predictions.
Reporting
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.
General Notification of Injured or Dead Marine Mammals--Navy
personnel would ensure that NMFS (the appropriate 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 shall
provide NMFS with species or description of the animal(s), the
conditions 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).
The Navy shall submit a report to the Office of Protected
Resources, NMFS, no later than 90 days after the expiration of the IHA.
The report shall, at a minimum, include the following marine mammal
sighting information:
Location of sighting;
Species;
Number of individuals;
Number of calves present;
Duration of sighting;
Behavior of marine mammals sighted;
Direction of travel;
Environmental information associated with each sighting
event, including Beaufort sea state, wave height, swell direction, wind
direction, wind speed, glare, percentage of glare, percentage of cloud
cover; and
Whether the sighting occurred before, during, or after a
detonation.
In addition, the Navy would provide information for all underwater
detonation events and ELCAS events under the IHA. This information
would include: total number of each type of underwater detonation
events and total number of piles driven/extracted during ELCAS.
The Navy would submit a draft report to NMFS, as described above,
and would respond to NMFS comments within 3 months of receipt. The
report would be considered final after the Navy has addressed NMFS'
comments, or 3 months after the submittal of the draft if NMFS does not
comment by then.
Past Monitoring and Reporting
The Navy has complied with monitoring and reporting requirements
under their previous IHAs for the SSTC. To date, two underwater
demolition training events have been observed by protected species
observers between July 2012 and November 2012. Broad scale Navy-funded
monitoring in support of the Navy's Southern California (SOCAL) Range
Complex Letter of Authorization has typically focused on the offshore
waters north and west of the SSTC. The Navy obtained special flight
permission to survey the vicinity of the SSTC during part of three
aerial surveys under the SOCAL monitoring plan in 2011-2012. As
anticipated, marine mammal sightings were limited and included several
California sea lions and a few unidentified dolphins, although the
dolphin sightings were several miles offshore from the normal SSTC
training area.
Estimated Take by Incidental Harassment
Estimated Marine Mammal Exposures from SSTC Underwater Detonations
The Navy's quantitative exposure modeling methodology estimated
numbers of animals 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 half of the annual training tempo to represent
each season. This approach results in an over-prediction of exposure to
typical training during a single year. Table 5 shows the 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.
For all underwater detonations, the Navy's impact model predicted no
marine mammal mortality and no Level A exposure to any species.
Table 5--The Navy's 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
---------------------- [mu]Pa\2\-s/23 psi [mu]Pa\2\-s/13.0 psi- 30.5 psi-ms
177 dB re 1 [mu]Pa ms
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gray Whale:
Warm........................................................ N/A N/A N/A N/A
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:
[[Page 24177]]
Warm........................................................ 0 0 0 0
Cold........................................................ 0 0 0 0
Long-beaked common dolphin:
Warm........................................................ 14 21 0 0
Cold........................................................ 7 10 0 0
Pacific white-sided dolphin:
Warm........................................................ 2 3 0 0
Cold........................................................ 3 4 0 0
Risso's dolphin:
Warm........................................................ 3 4 0 0
Cold........................................................ 11 15 0 0
Short-beaked common dolphin:
Warm........................................................ 123 177 0 0
Cold........................................................ 62 86 0 0
---------------------------------------------------------------------------------------
Total Annual Exposures.................................. 339 473 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
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. A couple of business rules
and assumptions are used in this determination:
1. 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). Given likely variable training schedules, an assumption
was made that approximately 20 of these 40 days would occur during the
warm water season, and 20 of the 40 days would occur during the cold
water season.
2. To be more conservative even to the point of over predicting
likely exposures, the Navy asserts that during the calculation there
can be no ``fractional'' exposures of marine mammals on a daily basis,
and all exposure values are rounded up during the calculation.
To estimate the potential ELCAS pile driving exposure, the
following expression is used:
Annual exposure = ZOI x warm season marine mammal density x warm
season pile driving days + ZOI x cold season marine mammal density x
cold season pile driving days, with ZOI = [pi] x R\2\, where R is the
radius of the ZOI.
An example showing the take calculation for bottlenose dolphins,
with the conservative ``daily rounding up'' business rule (2
above), is shown below:
Daily exposure = [pi] x 0.999\2\ x 0.202 + [pi] x 0.999\2\ x 0.202
= 0.6 + 0.6.
When rounding up the daily exposure 0.6 dolphin to 1 dolphin; the
annual exposure from warm season pile driving days (20 days) and cold
season pile driving days (20 days) is:
Annual exposure = 1 x 20 + 1 x 20 = 40
Based on the assessment using the methodology discussed previously,
applying the business rules and limitations described here, and without
consideration of mitigation measures, the take estimate is that ELCAS
pile driving is predicted to result in no Level A Harassment takes of
any marine mammal (received SPL of 190 dBrms for pinnipeds
and 180 dBrms re 1 [mu]Pa for cetacean, respectively) but
take of 40 bottlenose dolphins, 20 California sea lions, and 80 short-
beaked common dolphins by Level B behavioral harassment (Table 5).
II. Pile Removal
The same approach is applied for take estimation from ELCAS pile
removal. To estimate the potential ELCAS pile removal exposure, the
following expression is used:
Annual exposure = ZOI x warm season marine mammal density x warm
season pile removal days + ZOI x cold season marine mammal density x
cold season pile removal days, with ZOI = [pi] x R\2\, where R is the
radius of the ZOI.
An example showing the take calculation for bottlenose dolphins,
with the conservative ``daily rounding up'' business rule for pile
removal, is shown below:
Daily exposure = [pi] x 4.64\2\ x 0.202 + [pi] x 4.64\2\ x 0.202 =
13.7 + 13.7.
When rounding up the daily exposure 13.7 dolphins to 14 dolphins;
the annual exposure from warm season pile removal days (6 days) and
cold season pile removal days (6 days) is:
Annual exposure = 14 x 6 + 14 x 6 = 168
Based on the assessment using the methodology discussed previously,
applying the methods and limitations described here, and without
consideration of mitigation measures, the take estimate is that ELCAS
pile removal is predicted to result in no Level A Harassments takes of
any marine mammal; Level B exposures are shown in Table 6.
[[Page 24178]]
Table 6--Exposure Estimates From ELCAS Pile Driving and Removal Prior to Implementation of Mitigation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual marine mammal exposure (all sources)
---------------------------------------------------------------------------------------
Species Level B Behavior Level B Behavior Level A (Cetacean) Level A (Pinniped)
(Non-Impulse) 120 (Impulse) 120 dBrms 120 dBrms re 1 120 dBrms re 1
dBrms re 1 [mu]Pa re 1 [mu]Pa [mu]Pa [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
Long-beaked common dolphin
Installation................................................ N/A 0 0 0
Removal..................................................... 54 N/A 0 0
Pacific white-sided dolphin
Installation................................................ N/A 0 0 0
Removal..................................................... 12 N/A 0 0
Risso's dolphin
Installation................................................ N/A 0 0 0
Removal..................................................... 30 N/A 0 0
Short-beaked common dolphin
Installation................................................ N/A 80 0 0
Removal..................................................... 462 N/A 0 0
---------------------------------------------------------------------------------------
Total Annual Exposures.................................. 846 140 0 0
--------------------------------------------------------------------------------------------------------------------------------------------------------
In summary, for all underwater detonations and ELCAS pile driving
activities, 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.
Anticipated Effects on Habitat
The proposed training activities at SSTC would 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 would 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
[[Page 24179]]
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.
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 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 must consider other factors, such as the likely nature
of any responses (their intensity, duration, etc.), the context of any
responses (critical reproductive time or location, migration, etc.), or
any of the other variables mentioned in the first paragraph (if known),
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 planned explosives have relatively small zones
of influence. The locations of the proposed training activities 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 would 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 with
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.
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 20-490 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. 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
[[Page 24180]]
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 predicts 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. Further, the mitigation measures have been designed to
ensure that animals are detected in time to avoid injury or mortality
when TDFDs are used, in consideration of swim speed.
Additionally, as discussed previously, the 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 would 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.
Based on the analyses of the potential impacts from the proposed
underwater detonation training exercises conducted within the Navy's
SSTC action area, including the consideration of TDFD use and the
implementation of the improved marine mammal monitoring and mitigation
measures, NMFS has preliminarily determined that the Navy's proposed
activities within the SSTC would have a negligible impact on the marine
mammal species and stocks, provided that mitigation and monitoring
measures are implemented.
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 has prepared a Final Environmental Impact Statement (EIS)
for the proposed SSTC training activities. The FEIS was released in
January 2011 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 subsequently adopted
the FEIS for the SSTC training activities.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the Navy for activities at the SSTC, provided the
previously mentioned mitigation, monitoring, and reporting requirements
are incorporated. The proposed IHA language is provided below:
The Commander, U.S. Pacific Fleet, 250 Makalapa Drive, Pearl
Harbor, HI 96860-7000, and persons operating under his authority (i.e.,
Navy), are hereby authorized under section 101(a)(5)(D) of the Marine
Mammal Protection Act (16 U.S.C. 1371 (a)(5)(D)), to harass marine
mammals incidental to Navy training activities conducted in the Silver
Strand Training Complex (SSTC) in California.
1. This Incidental Harassment Authorization (IHA) is valid from
July 18, 2012, through July 17, 2013.
2. This IHA is valid only for training activities conducted at the
SSTC Study Area in the vicinity of San Diego Bay, California. The
geography location of the SSTC Study Area is located south of the City
of Coronado, California and north of the City of Imperial Beach,
California.
3. General Conditions.
(a) A copy of this IHA must be in the possession of the Commander,
his designees, and commanding officer(s) operating under the authority
of this IHA.
(b) The species authorized for taking are the California sea lion
(Zalophus californianus), Pacific Harbor seal (Phoca vitulina),
bottlenose dolphin (Tursiops truncatus), the eastern North Pacific gray
whale (Eschrichtius robustus), long-beaked common dolphin (Delphinus
capensis), short-beaked common dolphin (D. delphis), Pacific white-
sided dolphin (Lagenorhynchus obliquidens), and Risso's dolphin
(Grampus griseus).
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b).
(d) The taking by Level A harassment, injury or death of any of the
species listed in item 3(b) of the Authorization or the taking by
harassment, injury or death of any other species of marine mammal is
prohibited and may result in the modification, suspension, or
revocation of this IHA.
(e) In the unanticipated event that any cases of marine mammal
injury or mortality are judged to result from these activities, the
holder of this Authorization must immediately cease operations and
report the incident, as soon as clearance procedures allow, to the
Assistant Regional Administrator (ARA) for Protected Resources, NMFS
Southwest Region, phone (562) 980-4000 and to the Chief, Permits and
Conservation Division, Office of Protected Resources, NMFS, phone (301)
427-8401.
(i) The Navy shall suspend the training activities at the SSTC
until NMFS is able to review the incident and determine whether steps
can be taken to avoid further injury or mortality or until such taking
can be authorized under regulations promulgated under section
101(a)(5)(A) of the Marine Mammal Protection Act.
4. Mitigation Measures.
In order to ensure the least practicable impact on the species and
levels of takes listed in 3(b) and (c), the holder of this
Authorization is required to comply with the following mitigation
measures:
(a) Mitigation Measures for Underwater Detonations
(i) Mitigation and Monitoring Measures for Underwater Detonations
in Very Shallow Water (VSW, water depth < 24 ft)
(1) Mitigation and Monitoring Measures for VSW Underwater
Detonations Using Positive Control.
A. Underwater detonations using positive control (remote firing
devices) shall only be conducted during daylight.
B. Easily visible anchored floats shall be positioned on 700 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 mitigation zone.
C. For each VSW underwater detonation event, a safety-boat with a
minimum of one observer shall be launched 30 or more minutes prior to
detonation and moves through the area around the detonation site. The
safety-
[[Page 24181]]
boat observer shall be in constant radio communication with the
exercise coordinator and shore observer.
D. A shore-based observer shall also be deployed for VSW
detonations in addition to boat based observers. The shore observer
shall 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 or moving toward it.
E. At least 10 minutes prior to the planned initiation of the
detonation event sequence, the shore observer, on an elevated on-shore
position, shall begin a continuous visual search with binoculars of the
mitigation zone. At this time, the safety-boat observer shall inform
the shore observer if any marine mammal has been seen in the zone and,
together, both search the surface within and beyond the mitigation zone
for marine mammals.
F. The observers (boat and shore based) shall indicate that the
area is not clear any time a marine mammal is sighted in the mitigation
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.
G. Initiation of the detonation sequence shall 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 any observer that the area is not clear of marine mammals.
H. Following the detonation, visual monitoring of the mitigation
zone shall continue for 30 minutes for the appearance of any marine
mammal in the zone. Any marine mammal appearing in the area shall be
observed for signs of possible injury.
I. Any marine mammal observed after a VSW underwater detonation
either injured or exhibiting signs of distress shall be reported via
operational chain of command to Navy environmental representatives from
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 shall
report these events to the Stranding Coordinator of NMFS' Southwest
Regional Office. These voice or email reports shall 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.
(2) Mitigation and Monitoring Measures for VSW Underwater
Detonations Using Time-Delay (TDFD Only).
A. Underwater detonations using timed delay devices will only be
conducted during daylight.
B. Time-delays longer than 10 minutes shall not be used. The
initiation of the device shall not start until the mitigation area
below is clear for a full 30 minutes prior to initiation of the timer.
C. A mitigation zone shall be established around each underwater
detonation location as indicated in Table below based on charge weight
and length of time delay used.
Table 7--Updated Buffer Zone Radius (yd) for TDFDs Based on Size of Charge and Length of Time-Delay, With Additional Buffer Added to Account for Faster
Swim Speeds
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Time-delay
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5 min 6 min 7 min 8 min 9 min 10 min
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Charge Size (lb NEW)
5 lb..................... 1,000 yd........... 1,000 yd........... 1,000 yd........... 1,000 yd.......... 1,400 yd.......... 1,400 yd.
10 lb.................... 1,000 yd........... 1,000 yd........... 1,000 yd........... 1,400 yd.......... 1,400 yd.......... 1,400 yd.
15-29 lb................. 1,000 yd........... 1,400 yd........... 1,400 yd........... 1,400 yd.......... 1,500 yd.......... 1,500 yd.
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D. VSW ranges 1,000 yds:
(A) For each VSW underwater detonation event with a mitigation zone
of 1,000 yds, a safety boat with a minimum of one observer shall be
launched 30 or more minutes prior to detonation and moves through the
area around the detonation site at the seaward edge of the mitigation
zone. The task of the boat 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 shall be in constant
radio communication with the exercise coordinator and shore observer
discussed below. To the best extent practical, boats will try to
maintain a 10 knot search speed.
(B) A shore-based observer shall also be deployed for VSW
detonations in addition to boat based observers. 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. The safety-boat
observer shall inform the shore observer if any marine mammal has been
seen in the zone and, together, both search the surface within and
beyond the mitigation zone for marine mammals. The shore observer shall
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 or moving toward it.
E. VSW ranges larger than 1,400 yards:
(A) A minimum of 2 boats shall be used to survey for marine mammals
at mitigation ranges larger than 1,400 yards.
(B) When conducting the surveys within a mitigation zone >1,400
yds, boats shall position themselves near the mid-point of the
mitigation zone radius (but always outside the detonation plume radius/
human safety zone) and travel in a semi-circular pattern around the
detonation location surveying both the inner (toward detonation site)
and outer (away from detonation site) areas. When using 2 boats, each
boat shall be positioned on opposite sides of the detonation location,
separated by 180 degrees. If using more than 2 boats, each boat shall
be positioned equidistant from one another (120 degrees separation for
3 boats, 90 degrees separation for 4 boats, etc.). If available, aerial
visual survey support from Navy helicopters can be utilized, so long as
it shall not jeopardize safety of flight. Helicopters will travel in a
circular pattern around the detonation location.
F. A mitigation zone shall be surveyed from 30 minutes prior to the
detonation and for 30 minutes after the detonation.
G. Other personnel besides boat observers shall also maintain
situational awareness on the presence of marine mammals within the
mitigation zone to
[[Page 24182]]
the best extent practical given dive safety considerations. Divers
placing the charges on mines shall observe the immediate underwater
area around a detonation site for marine mammals and report sightings
to surface observers.
H. If a marine mammal is sighted within an established mitigation
zone or moving towards it, underwater detonation events shall be
suspended until the marine mammal has voluntarily left the area and the
area is clear of marine mammals for at least 30 minutes.
I. Immediately following the detonation, visual monitoring for
affected marine mammals within the mitigation zone shall continue for
30 minutes.
J. Any marine mammal observed after an underwater detonation either
injured or exhibiting signs of distress shall be reported via Navy
operational chain of command to Navy environmental representatives from
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 shall
report these events to the Stranding Coordinator of NMFS' Southwest
Regional Office. These voice or email reports shall 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) Mitigation and Monitoring Measures for Underwater Detonations
in Shallow Water (>24 Feet)
(1) Mitigation and Monitoring Measures for Underwater Detonations
Using Positive Control (Except SWAG and Timed Detonations).
A. Underwater detonations using positive control devices shall only
be conducted during daylight.
B. A mitigation zone of 700 yards shall be established around each
underwater detonation point.
C. A minimum of two boats, including but not limited to small
zodiacs and 7-m Rigid Hulled Inflatable Boats (RHIB) shall be deployed.
One boat shall act as an observer platform, while the other boat is
typically the diver support boat.
D. Two observers with binoculars on one small craft/boat shall
survey the 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.
E. 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.
F. If a marine mammal is sighted within the 700 yard mitigation
zone or moving towards it, underwater detonation events shall be
suspended until the marine mammal has voluntarily left the area and the
area is clear of marine mammals for at least 30 minutes.
G. Immediately following the detonation, visual monitoring for
marine mammals within the mitigation zone shall continue for 30
minutes. Any marine mammal observed after an underwater detonation
either injured or exhibiting signs of distress shall be reported to via
Navy operational chain of command to Navy environmental representatives
from 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 email reports shall 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.
(2) Mitigation and Monitoring Measures for Underwater Detonations
Using Time-Delay (TDFD Detonations Only)
A. Underwater detonations using timed delay devices shall only be
conducted during daylight.
B. Time-delays longer than 10 minutes shall not be used. The
initiation of the device shall not start until the mitigation area
below is clear for a full 30 minutes prior to initiation of the timer.
C. A mitigation zone shall be established around each underwater
detonation location as indicated in Table above based on charge weight
and length of time-delay used. When conducting the surveys within a
mitigation zone (either 1,000 or 1,400 yds), boats shall position
themselves near the mid-point of the mitigation zone radius (but always
outside the detonation plume radius/human safety zone) and travel in a
circular pattern around the detonation location surveying both the
inner (toward detonation site) and outer (away from detonation site)
areas.
D. Shallow water TDFD detonations range 1,000 yds:
(A) A minimum of 2 boats shall be used to survey for marine mammals
at mitigation ranges of 1,000 yds.
(B) When using 2 boats, each boat shall be positioned on opposite
sides of the detonation location, separated by 180 degrees.
(C) Two observers in each of the boats shall conduct continuous
visual survey of the mitigation zone for the entire duration of a
training event.
(D) To the best extent practical, boats shall try to maintain a 10
knot search speed. This search speed was added to ensure adequate
coverage of the buffer zone during observation periods. While weather
conditions and sea states may require slower speeds in some instances,
10 knots is a prudent, safe, and executable speed that will allow for
adequate surveillance. For a 1,000 yd radius buffer zone a boat
travelling at 10 knots and 500 yds away from the detonation point would
circle the detonation point 3.22 times during a 30 minute survey
period. By using 2 boats, 6.44 circles around the detonation point
would be completed in a 30 minute span.
E. Shallow water TDFD detonations greater than 1,400 yds:
(A) A minimum of 3 boats or 2 boats and 1 helicopter shall be used
to survey for marine mammals at mitigation ranges of 1,400 yds.
(B) When using 3 (or more) boats, each boat shall be positioned
equidistant from one another (120 degrees separation for 3 boats, 90
degrees separation for 4 boats, etc.).
(C) For a 1,400 yd radius mitigation zone, a 10 knot speed results
in 2.3 circles for each of the three boats, or nearly 7 circles around
the detonation point over a 30 minute span.
(D) If available, aerial visual survey support from Navy
helicopters shall be utilized, so long as it will not jeopardize safety
of flight.
(E) Helicopters, if available, shall be used in lieu of one of the
boat requirements. A helicopter search pattern is dictated by standard
Navy protocols and accounts for multiple variables, such as the size
and shape of the search area, size of the object being searched for,
and local environmental conditions, among others.
F. A mitigation zone shall be surveyed from 30 minutes prior to the
detonation and for 30 minutes after the detonation.
G. Other personnel besides boat observers can also maintain
situational awareness on the presence of marine mammals within the
mitigation zone to the best extent practical given dive safety
considerations. Divers placing the charges on mines shall observe the
immediate underwater area around a
[[Page 24183]]
detonation site for marine mammals and report sightings to surface
observers.
H. If a marine mammal is sighted within an established mitigation
zone or moving towards it, underwater detonation events shall be
suspended until the marine mammal has voluntarily left the area and the
area is clear of marine mammals for at least 30 minutes.
I. Immediately following the detonation, visual monitoring for
affected marine mammals within the mitigation zone shall continue for
30 minutes.
J. Any marine mammal observed after an underwater detonation either
injured or exhibiting signs of distress shall be reported via Navy
operational chain of command to Navy environmental representatives from
U.S. Pacific Fleet, Environmental Office, San Diego Detachment or Pearl
Harbor. Using Marine Mammal Stranding protocols and communication trees
established for the Southern California and Hawaii Range Complexes, the
Navy shall report these events to the Stranding Coordinator of NMFS'
Southwest or Pacific Islands Regional Office. These voice or email
reports shall 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.
(3) Mitigation and Monitoring Measures for Underwater SWAG
Detonations (SWAG Only).
A. Underwater detonations using SWAG shall only be conducted during
daylight.
B. A mitigation zone of 60 yards shall be established around each
SWAG detonation site.
C. A minimum of two boats, including but not limited to small
zodiacs and 7-m Rigid Hulled Inflatable Boats (RHIB) shall be deployed.
One boat shall act as an observer platform, while the other boat is
typically the diver support boat.
D. Two observers with binoculars on one small craft\boat shall
survey the detonation area and the mitigation zone for marine mammals
from at least 10 minutes prior to commencement of the scheduled
explosive event and until at least 10 minutes after detonation.
E. In addition to the dedicated observers, all divers and boat
operators engaged in detonation events shall monitor the area
immediately surrounding the point of detonation for marine mammals when
possible.
F. Divers and personnel in support boats shall monitor for marine
mammals out to the 60 yard mitigation zone for 10 minutes prior to any
detonation.
G. After the detonation, visual monitoring for marine mammals shall
continue for 10 minutes. Any marine mammal observed after an underwater
detonation either injured or exhibiting signs of distress shall be
reported via Navy operational chain of command to Navy environmental
representatives from 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 shall report these events to the Stranding
Coordinator of NMFS' Southwest Regional Office. These voice or email
reports shall 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.
(a) Mitigation for ELCAS Training at SSTC
(1) Safety Zone: A safety zone shall be established at 150 feet (50
yards) from ELCAS pile driving or removal events. This safety zone is
base on the predicted range to Level A harassment (180
dBrms) for cetaceans during pile driving, and is being
applied conservatively to both cetaceans and pinnipeds during pile
driving and removal.
(2) If marine mammals are found within the 150-foot (50-yard)
safety zone, pile driving or removal events shall be halted until the
marine mammals have voluntarily left the mitigation zone.
(3) Monitoring for marine mammals shall be conducted within the
zone of influence and take place at 30 minutes before, during, and 30
minutes after pile driving and removal activities, including ramp-up
periods. A minimum of one trained observer shall be placed on shore, on
the ELCAS, or in a boat at the best vantage point(s) practicable to
monitor for marine mammals.
(4) Monitoring observer(s) shall implement shut-down/delay
procedures by calling for shut-down to the hammer operator when marine
mammals are sighted within the safety zone. After a shut-down/delay,
pile driving or removal shall not be resumed until the marine mammal
within the safety zone is confirmed to have left the area or 30 minutes
have passed without seeing the animal.
(5) Soft Start--ELCAS pile driving shall 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.
(6) Emergency Shut-down Related to Marine Mammal Injury and
Mortality--If there is clear evidence that a marine mammal is injured
or killed as a result of the proposed Navy training activities (e.g.,
instances in which it is clear that munitions explosions caused the
injury or death), the Naval activities shall be immediately suspended
and the situation immediately reported by personnel involved in the
activity to the officer in charge of the training, who will follow Navy
procedures for reporting the incident to NMFS through the Navy's chain-
of-command.
1. Monitoring Measures
In order to ensure the least practicable impact on the species and
levels of takes listed in 3(b) and (c), the holder of this
Authorization is required to comply with the following monitoring
measures:
(i) Marine Mammal Observer at a Sub-set of SSTC Underwater
Detonation:
(1) Civilian scientists acting as protected species observers
(PSOs) shall be used to observe a sub-set of the SSTC underwater
detonation events. The PSOs shall 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.
(2) PSOs shall be field-experienced observers that are either Navy
biologists or contracted marine biologists. These civilian PSOs shall
be placed either alongside existing Navy SSTC operators during a sub-
set of training events, or on a separate small boat viewing platform.
(3) PSOs shall collect the same data currently being collected for
more elaborate offshore ship-based observations including but not
limited to:
A. location of sighting;
B. species;
C. number of individuals;
D. number of calves present;
E. duration of sighting;
F. behavior of marine animals sighted;
G. direction of travel;
H. 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
I. when in relation to Navy training did the sighting occur
[before, during or after the detonation(s)].
[[Page 24184]]
(1) The PSOs will not be part of the Navy's formal reporting chain
of command during their data collection efforts. Exceptions can be made
if a marine mammal is observed by the PSO within the SSTC specific
mitigation zones the Navy has formally proposed to the NMFS. The PSO
shall inform any Navy operator of the sighting so that appropriate
action may be taken by the Navy trainees.
(i) ELCAS Visual Monitoring: The Navy shall place monitoring
personnel to note any observations during the entire pile driving
sequence, including ``soft start'' period, for later analysis.
Information regarding species observed during pile driving and removal
events (including soft start period) shall include:
(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 pile driving or removal).
(i) ELCAS Acoustic Monitoring: The Navy shall conduct underwater
acoustic propagation monitoring during the first available ELCAS
deployment at the SSTC. These acoustic monitoring results shall be used
to either confirm or refine the Navy's zones of safety and influence
for pile driving and removal listed in 4(b)(1).
1. Reporting Measures
(i) The Navy shall report results obtained annually from the
Southern California Range Complex Monitoring Plan for areas pertinent
to the SSTC, if applicable.
(ii) The Navy shall submit a report to the Office of Protected
Resources, NMFS, no later than 90 days after the expiration of the IHA.
The report shall, 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
(9) when in relation to Navy training did the sighting occur
[before, during or after the detonation(s)].
(i) In addition, the Navy shall provide the information for all of
its underwater detonation events and ELCAS events under the IHA. The
information shall include: (1) Total number of each type of underwater
detonation events conducted at the SSTC, and (2) total number of piles
driven and extracted during the ELCAS exercise.
(ii) The Navy shall submit to NMFS a draft report as described
above and shall respond to NMFS comments within 3 months of receipt.
The report will be considered final after the Navy has addressed NMFS'
comments, or 3 months after the submittal of the draft if NMFS does not
comment by then.
1. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
the authorized taking is having more than a negligible impact on the
species or stock of affected marine mammals.
Dated: April 18, 2013.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2013-09618 Filed 4-23-13; 8:45 am]
BILLING CODE 3510-22-P