Takes of Marine Mammals Incidental to Specified Activities; Antioch Bridge Seismic Retrofit Project, California, 67856-67861 [E9-30179]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 74, Number 243 (Monday, December 21, 2009)]
[Notices]
[Pages 67856-67861]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-30179]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XS24


Takes of Marine Mammals Incidental to Specified Activities; 
Antioch Bridge Seismic Retrofit Project, California

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

ACTION:  Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY:  NMFS has received an application from the California 
Department of Transportation (Caltrans) for an Incidental Harassment 
Authorization (IHA) to take marine mammals, by harassment, incidental 
to the Antioch Bridge Seismic Retrofit Project. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an IHA to Caltrans to incidentally harass, by Level B 
Harassment only, 10 harbor seals (Phoca vitulina) and 10 California sea 
lions (Zalophus californianus) during the specified activity.

DATES:  Comments and information must be received no later than January 
20, 2010.

ADDRESSES:  Comments on the application should be addressed to Michael 
Payne, Chief, Permits, Conservation and Education Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing email comments is PR1.0648-XS24@noaa.gov. NMFS is not 
responsible for e-mail comments sent to addresses other than the one 
provided here. Comments sent via e-mail, including all attachments, 
must not exceed a 10-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information 
(for example, name, address, etc.) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this 
notice may also be viewed, by appointment, during regular business 
hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT:  Jaclyn Daly, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 151.

SUPPLEMENTARY INFORMATION:

Background

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

Summary of Request

    On May 5, 2009, NMFS received an application from Caltrans for the 
taking, by Level B harassment, of marine mammals incidental to 
retrofitting the Antioch Bridge, located 5.4 miles east of the 
confluence of the Sacramento and San Joaquin Rivers. To access shallow 
water piers, a temporary support trestle would be installed using a 
pile driver hammer. Because pile driving has the potential to result in 
behavioral harassment to marine mammals located in the action area, an 
authorization under section 101(a)(5)(D) of the MMPA is warranted.

Description of the Specified Activity

    The Antioch Bridge, completed in 1978, was designed based on 
seismic standards that the Caltrans established in 1971. After the Loma 
Prieta in 1989, Caltrans implemented the Seismic Retrofit Program. 
After the Northridge Earthquake of 1994, Caltrans implemented Phase Two 
of the Program, which required seven state-owned toll bridges, 
including the Antioch Bridge, to be retrofitted. The Antioch Seismic

[[Page 67857]]

Retrofit Project would provide a seismic upgrade of the Antioch Bridge; 
the upgrade would meet the current requirements.
    The Antioch Bridge is 9,437-ft long, accommodates one lane of 
traffic in either direction, and includes narrow accommodation for 
bicyclists and pedestrians. Proposed retrofit elements to the bridge 
include installation of steel bracings; replacement of the existing 
elastometric bearings with isolation bearings; and removal of the 
existing curtain walls and retrofit of all the columns within the slab 
span structure. To accomplish this, a temporary trestle would be built 
to allow access to the piers in shallow water (out to Pier 11). The 
temporary marine trestle would be constructed from the south shore of 
the San Joaquin River; out approximately 910-ft into the river along 
the west side of the existing bridge structure. This is where water 
depths are less than 10-ft below mean lower-low water (MLLW) and are 
too shallow to be accessed by barge. The trestle will be 25 ft wide 
with piles spaced 25-ft apart. It will be constructed using 
approximately 160 24-in steel hollow shell piles which will be 
installed with a vibratory hammer. Vibrating a single 24-in pile into 
place requires, at the most, ten minutes of noise generating vibration. 
In addition, Caltrans will ``proof'' or test one pile per day using an 
impact hammer to ensure the pile can sustain the required load. 
Proofing the piles would require approximately 20 blows per day, 
generating sound pressure for about one minute per day. The entire 
project is expected to take 2.5 years to complete; however, 
installation of the temporary piles is expected to take approximately 4 
months and is planned for August 1- November 1, 2010. At the completion 
of the project, the trestle and all piles would be removed. All pile 
driving would be conducted during daylight hours only.
    Some components of the project, (e.g., creation of access roads; 
installation of bracings) would not involve in-water work and therefore 
are not expected to harass marine mammals. In-air noise from these 
activities is not a concern in this case as pinnipeds are not known to 
haul-out near the bridge (see Affected Environment). Therefore, NMFS 
has preliminary determined that these specified activities do not 
warrant an authorization and they will not be discussed further.

Action Area

    The Antioch Bridge project area includes Caltrans right-of-way 
(ROW) and temporary construction easements. This area covers 
approximately 62 acres (ac), including 7.5 ac on the south shore of the 
San Joaquin River in Contra Costa County, 21 ac of the San Joaquin 
River, and 33.5 ac on Sherman Island in Sacramento County. On the south 
side of the river, vegetation is primarily park landscaping, with weedy 
ruderal vegetation under the existing bridge. A small fringe wetland is 
found along the San Joaquin River around the bridge.
    The San Joaquin River is relatively shallow on the south side, with 
depths of less than 10-ft out to Pier 11. The main channel extends 
between Piers 12 and 20, with deep water passage between Piers 19 and 
20, near the northern shore. On the north side of the river, Sherman 
Island supports irrigated pasture and irrigated crops, as well as an 
area of ruderal vegetation in fallow fields. Mayberry Slough and an 
irrigation canal cross the area in the vicinity of Piers 39 and 40, and 
Pier 32, respectively. The waters around the bridge are not heavily 
used by marine mammals but do provide some foraging habitat for certain 
pinniped species.

Description of Marine Mammals in the Area of the Specified Activity

    The project area lies outside the range of most marine mammal 
species. The Guadalupe fur seal (Arctocephalus townsendi), northern 
elephant seal (Mirounga angustirostris), northern fur-seal (Callorhinus 
ursinus), and northern (Stellar) sea lion (Eumetopias jubatus) have 
distributions that extend northward along the California coast but 
their ranges do not extend into the bays and estuaries of the Delta. 
There have been two documented occurrences of humpback whales 
(Megaptera novaeangliae) traveling up the Sacramento River, but these 
occurrences do not represent the normal behavior patterns of the 
species. Occurrences of humpback whales have never been documented and 
are not anticipated at the bridge location.
    The only marine mammal species which may be affected by the project 
are the California sea lion and Pacific harbor seal. Both species have 
been known to sporadically venture into estuaries and rivers in search 
of food, and the California Department of Fish and Game (CDFG) 
indicates that the ranges of these two species encompasses the region 
of the Delta in which the project occurs.

California Sea Lion

    The California sea lion is the most abundant marine mammal in 
California with an estimated population of 50,000 along the entire 
California coast and islands. The entire US population has been 
estimated at 238,000 in 2005, and growing at a rate of approximately 
6.52 % annually between 1975 and 2005 (NMFS, 2007). The California 
stock of sea lions is not listed as depleted under the MMPA or 
threatened or endangered under the MMPA.
    California sea lions exhibit seasonal migration patterns organized 
around their breeding patterns. The sea lions breed in rookeries in the 
Channel Islands and Mexico from May through August. Females tend to 
remain close to the rookeries throughout the year, while males migrate 
north after the breeding season in the late summer, and then migrate 
back south to the breeding grounds in the spring (CDFG, 1990).
    Sea lions feed on fish and cephalopods, including Pacific whiting, 
rockfish, anchovy, hake, flat-fish, small sharks, squid, and octopus. 
Sea lions are often solitary feeders; however they also hunt in groups 
which can vary in size according to the abundance of prey. Within the 
action area; sea lions are often solitary.
    Main breeding rookeries are found in the Channel Islands. Males 
haul out on Farallon Island and Ano Nuevo Island throughout the year. 
Sea lions can be found at sea from the surf zone out to near shore and 
pelagic waters. On land, the sea lions are found resting and breeding 
in groups of various sizes, and haul out on rocky surfaces and 
outcroppings and beaches, as well as manmade structures such as jetties 
and buoys. Sea lions prefer haulout sites and rookeries near abundant 
food supplies, with easy access to water; although sea lions 
occasionally travel up rivers and bays in search of food.
    No known haulout sites occur in the vicinity of the bridge. During 
the designated August 1 to November 30 work window for installing the 
temporary marine trestle, California sea lions will likely be absent 
during August, as they are still in the breeding season and will be 
located further south, in the Channel Islands (CDFG 1990). Beginning in 
September, the likelihood of sea lions foraging in the San Joaquin 
River Delta increases, as males are beginning to return from the 
Channel Island rookeries at this time (CDFG 1990).

Harbor Seals

    Harbor seals are the most widely distributed pinniped species, 
occurring on both sides of the northern Pacific and Atlantic Ocean 
(NMFS 2005). The Pacific harbor seal ranges from Baja Mexico to the 
Aleutian Islands, and occurs along the entire length of the California 
coast. Harbor seal populations in California were estimated at 34,233 
in 2005, and have

[[Page 67858]]

been growing at an estimated rate of 3.5 % from 1982 to 1995 (NMFS 
2005). Harbor seals are not listed as depleted under the MMPA or 
threatened or endangered under the MMPA.
    The breeding season lasts from March through June each year, with 
peak births occurring between April and May. Females give birth to one 
pup each year, and mate again shortly after weaning. Harbor seals are 
not territorial on land, but do maintain spacing between individuals in 
haul outs.
    Harbor seals feed on fish, crustaceans and some cephalopods. 
Foraging occurs in shallow littoral waters, and common prey items 
include flounder, sole, hake, codfish, sculpin, anchovy and herring. 
Harbor seals are typically solitary while foraging, although small 
groups have been observed. Seals spotted within the action area are 
usually solitary.
    Unlike California sea lions, harbor seals are rarely found in 
pelagic waters and typically stay within the tidal and intertidal 
zones. On land, harbor seals haul out on rocky outcrops, mudflats, 
sandbars and sandy beaches with unrestricted access to water and with 
minimal human presence. Harbor seals are non-migratory, but will make 
short to-moderate distance journeys for feeding and breeding needs, 
including venturing into estuaries and rivers (CDFG 2005).
    The area of the Delta where the project occurs falls within the 
limits of the range of harbor seals; however, no known haulout sites 
have been identified in the vicinity of the bridge. Potential 
occurrences of harbor seals would be limited to individuals in search 
of food upstream into the San Joaquin River.

Potential Effects on Marine Mammals

    Sound is a physical phenomenon consisting of minute vibrations that 
travel through a medium, such as air or water. Sound levels are 
compared to a reference sound pressure to identify the medium. For air 
and water, these reference pressures are ``re 20 microPa'' and ``re 1 
microPa'', respectively. Sound is generally characterized by several 
variables, including frequency and sound level. Frequency describes the 
sound's pitch and is measured in hertz (Hz) or kilohertz (kHz), while 
sound level describes the sound's loudness and is measured in decibels 
(dB). Sound level increases or decreases exponentially with each dB of 
change. For example, 10-dB yields a sound level 10 times more intense 
than 1 dB, while a 20 dB level equates to 100 times more intense, and a 
30 dB level is 1,000 times more intense. However, it should be noted 
that humans perceive a 10 dB increase in sound level as only a doubling 
of sound loudness, and a 10 dB decrease in sound level as a halving of 
sound loudness.
    Marine mammals use sound for vital life functions, and introducing 
sound into their environment could be disrupting to those behaviors. 
Sound (hearing and vocalization/ echolocation) serves 4 main functions 
for marine mammals. These functions include (1) providing information 
about their environment; (2) communication; (3) enabling remote 
detection of prey; and (4) enabling detection of predators. Noise from 
pile driving may affect marine mammals at a level which could cause 
behavioral harassment. The distances to which these sounds are audible 
depend on source levels, ambient noise levels, and sensitivity of the 
receptor (Richardson et al. 1995). Mitigation measures (see Mitigation 
section) and the low source level of vibratory pile driving (the main 
method used to install piles) are expected to prevent injurious 
exposure.
    Pinnipeds produce a wide range of hearing social signals, most 
occurring at relatively low frequencies (Southall et al., 2007), 
suggesting hearing is keenest at these frequencies. Pinnipeds 
communicate acoustically both on land and in the water suggesting they 
possess amphibious hearing and have difference hearing capabilities 
dependant upon the media (air or water). Based on numerous studies, as 
summarized in Southall et al. (2007), pinnipeds are more sensitive to a 
broader range of sound frequencies in water than in air. In-water, 
pinnipeds can hear frequencies from 75 Hz to 75kHz. In-air, the lower 
limit remains at 75 Hz but the highest audible frequencies are only 
around 30kHz (Southall, et al., 2007).

Hearing Impairment

    Temporary or permanent hearing impairment is a possibility when 
marine mammals are exposed to very loud sounds. Hearing impairment is 
measured in two forms: temporary threshold shift and permanent 
threshold shift. Relationships between TTS and PTS thresholds have not 
been studied in marine mammals, but are assumed to be similar to those 
in humans and other terrestrial mammals. There is no empirical data for 
onset of PTS in any marine mammal, and therefore, PTS- onset must be 
estimated from TTS-onset measurements and from the rate of TTS growth 
with increasing exposure levels above the level eliciting TTS-onset. 
PTS is presumed to be likely if the threshold is reduced by [gteqt] 40 
dB (i.e., 40 dB of TTS). Due to proposed mitigation measures and source 
levels, NMFS does not expect that marine mammals will be exposed to 
levels that could elicit PTS and therefore it will not be discussed 
further.

Temporary Threshold Shift (TTS)

    TTS is the mildest form of hearing impairment that can occur during 
exposure to a loud sound (Kryter, 1985). While experiencing TTS, the 
hearing threshold rises and a sound must be louder in order to be 
heard. TTS can last from minutes or hours to (in cases of strong TTS) 
days. For sound exposures at or somewhat above the TTS-onset threshold, 
hearing sensitivity recovers rapidly after exposure to the noise ends. 
Few data on sound levels and durations necessary to elicit mild TTS 
have been obtained for marine mammals. Southall et al. (2007) considers 
a 6 dB TTS (i.e., baseline thresholds are elevated by 6 dB) sufficient 
to be recognized as an unequivocal deviation and thus a sufficient 
definition of TTS-onset. Because it is non-injurious, NMFS considers 
TTS Level B harassment that is mediated by physiological effects on the 
auditory system; however, NMFS does not consider onset TTS to be the 
lowest level at which Level B harassment may occur.
    Sound exposures that elicit TTS in pinnipeds underwater have been 
measured in harbor seals, California sea lions, and northern elephant 
seals from broadband or octaveband (OBN) non-pulse noise ranging from 
approximately 12 minutes to several hours (Kastak and Schusterman, 
1996; Finneran et al., 2003; Kastak et al., 1999; Kastak et al., 2005). 
Collectively, Kastak et al. (2005) analyzed these data to indicate that 
in the harbor seal, a TTS of ca. 6 dB occurred with 25 minute exposure 
to 2.5 kHz OBN with SPL of 152 dB re:1 microPa; the California sea lion 
showed TTS-onset at 174 dB re: 1 microPa (as summarized in Southall et 
al., 2007). Underwater TTS experiments involving exposure to pulse 
noise is limited to a single study. Finneran et al. (2003) found no 
measurable TTS when two California sea lions were exposed to sounds up 
to 183 dB re: 1 microPa (peak-to-peak).

Behavioral Impacts

    The source of underwater noise during construction would be pile 
driving to construct the temporary work trestle. There are limited data 
available on the effects of non-pulse noise on pinnipeds in-water; 
however, field and captive studies to date collectively suggest that 
pinnipeds do not strongly react to exposures between 90-140 dB re: 1 
microPa. Jacobs and Terhune (2002) observed wild harbor seal

[[Page 67859]]

reactions to acoustic harassment devices (ADH) around nine sites. Seals 
came within 44 m of the active ADH and failed to demonstrate any 
behavioral response when received SPLs were estimated at 120-130 dB re: 
1 microPa. In a captive study, a group of seals were collectively 
subjected to non-pulse sounds (e.g., vibratory pile driving) at 8-16 
kHz (Kastelein, 2006). Exposures between 80-107 dB re: 1 microPa did 
not induce strong behavioral responses; however, a single observation 
at 100-110 dB re: 1 microPa indicated an avoidance response at this 
level. The group returned to baseline conditions following exposure 
(i.e., no long term impact). Southall et al. (2007) notes contextual 
differences between these two studies noting that the captive animals 
were not reinforced with food for remaining in the noise fields, 
whereas free-ranging subjects may have been more tolerant of exposures 
because of motivation to return to a safe location or approach 
enclosures holding prey items. Southall et al. (2007) reviewed relevant 
data from studies involving pinnipeds exposed to pulse noise (e.g., 
impact pile driving) and concluded that exposures to 150 to 180 dB re: 
1 microPa generally have limited potential to induce avoidance 
behavior.
    Seals and sea lions exposed to threshold level sounds (120 dB for 
non-pulse; 160 dB for pulse) may elicit temporary avoidance behavior 
around the bridge, which may affect movement of seals under the bridge 
or temporarily inhibit them from foraging near the bridge. However, 
limiting pile driving to one to hours per day would allow for minimal 
disruption of harbor seal foraging or use of dispersal habitat. Very 
few sea lions use the South Bay for foraging and no known sea lion 
haul-outs exist in the South Bay; therefore, impacts are expected to be 
equally minimal than those of harbor seals.
    Based on these studies, NMFS has preliminarily determined that 
seals and sea lions exposed to threshold level sounds (120 dB for non-
pulse; 160 dB for pulse) may elicit temporary pinniped avoidance 
behavior. The most likely impact to pinnipeds from the pile 
installation would be temporary disruption of feeding patterns as 
individual sea lions or harbor seals pass through the area in pursuit 
of food. However, limiting pile driving to one to two hours per day 
would allow for minimal disruption of foraging or use of dispersal 
habitat. No haulouts exist and no pupping or breeding is known to occur 
on land near the bridge; therefore, no impacts to reproduction or 
interruption of mom/pup bonding or nursing are anticipated. Temporary 
hearing loss is possible for those pinnipeds that enter into zone of 
Level B harassment, but permanent hearing loss or other harm is not 
anticipated due to monitoring and mitigation efforts, as described 
below) and low source level of pile driving.

Estimated Take by Incidental Harassment

    NMFS typically uses threshold sound levels to estimate takes and 
establish appropriate mitigation. Current NMFS practice regarding 
exposure of marine mammals to anthropogenic noise is that in order to 
avoid injury of marine mammals (e.g., PTS), cetaceans and pinnipeds 
should not be exposed to impulsive sounds of 180 and 190 dB rms or 
above, respectively. This level is considered precautionary as it is 
likely that more intense sounds would be required before injury would 
actually occur (Southall et al., 2007). As such, Caltrans has proposed 
safety zones based on hydroacoustical modeling for the pile sizes and 
type of hammers used for the Dumbarton Bridge project and water depth. 
The model simulates spherical spreading and uses a transmission 
constant of 15. Potential for behavioral harassment (Level B) is 
considered to have occurred when marine mammals are exposed to sounds 
at or above 160dB rms for impulse sounds (e.g., impact pile driving) 
and 120dB rms for non-pulse noise (e.g., vibratory pile driving), but 
below the aforementioned thresholds. These levels are considered 
precautionary. Estimated distances to NMFS' current harassment 
threshold levels from pile driving during the proposed action are 
outlined in Table 1 below.

                                 Table 1: Underwater distances to NMFS harassment threshold levels during pile driving.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Sound Levels (rms)
                   Pile Type                           Hammer Type       -------------------------------------------------------------------------------
                                                                                    190 dB                     160 dB                    120 dB
--------------------------------------------------------------------------------------------------------------------------------------------------------
24`` steel                                                       Impact              16.8 m (55 ft)        1,000 m (3,280 ft)                       n/a
24`` steel                                                    Vibratory                         n/a                       n/a      16.4 km (10.2 miles)
--------------------------------------------------------------------------------------------------------------------------------------------------------

    For the impact portion of the trestle pile installation, a source 
level of 194 dB RMS at 35-ft was used to calculate NMFS level 
harassment distances. Based on this source level, models estimated that 
pile installation for the Project could generate sound levels above 190 
dB that would extend out about 55-ft from the pile. The calculated 
distance for sounds above 160 dB (Level B harassment) is approximately 
3,300-ft. For the vibratory portion of the trestle pile installation, a 
source level of 166 dB RMS at 35-ft is assumed; therefore, sound levels 
above 190 dB would not be reached during the installation of piles by 
vibratory hammer. The calculated distance for sounds above 120 dB 
(Level B harassment threshold for non-impulse sounds) would be around 
10.2 miles.
    Current NMFS practice regarding in-air exposure of pinnipeds to 
noise generated from human activity is that the onset of Level B 
harassment for harbor seals and all other pinnipeds is 90 dBrms 
and 100 dB rms re: 20 micoPa, respectively. In-air noise 
calculations from pile driving for the Dumbarton Bridge project, which 
uses the same size and type of piles and hammers, predict that noise 
levels will be reduced to approximately 83 dB rms re: 20 
microPa at 800m. Harbor seals or California sea lions are not known to 
haul-out anywhere near the Antioch Bridge; therefore, in-air noise is 
not considered to contribute to harassment for this project.
    It is difficult to estimate the number of California sea lions and 
Pacific harbor seals that could be affected by the installation of 
piles for the temporary marine trestle, as pinnipeds only sporadically 
venture into the project area in pursuit of food. Due to the project 
location lying at the extreme margins of these species' ranges, the 
number of individual pinnipeds expected to be encountered is very low. 
Through consultation with NMFS' Southeast Regional Office, Caltrans 
requests the take of 10 California seal lions. These individuals would 
most likely be adult males, as the females and pups tend to remain 
close to the breeding rookeries. Similarly, Caltrans requests, and 
NMFS' proposes, authorization to take 10 individual

[[Page 67860]]

harbor seals incidental to pile driving activities; also likely males 
in pursuit of food.

Proposed Mitigation

    Caltrans has proposed mitigation both in their application and 
supplemental communication to reduce impact to environmental resources. 
Measures set in place to protect birds and fish (e.g., using the 
vibratory hammer at all times except for load bearing tests) also 
protect marine mammals. The following proposed mitigation measures are 
designed to eliminate potential for injury and reduce Level B 
harassment of marine mammals.

Establishment of safety and zones and shut down requirements

    Vibratory pile driving does not elicit source levels at or above 
NMFS' harassment threshold for Level A harassment, therefore, no 
required shut down zones would be established for vibratory pile 
driving. The isopleth for the Level A harassment threshold (190 dB) is 
modeled to be within 55 ft (16.8 m) of the impact pile hammer (see 
Table 1); however, Caltrans has proposed to delay impact pile driving 
should a marine mammal come within or approach 100 ft (30 m) of the 
pile being driven; further reducing the risk of Level A harassment.

Limited use of impact hammer

    As a result of Section 7 consultation discussions with NMFS, 
Caltrans has agreed to drive all temporary piles with a vibratory 
hammer, to reduce impacts to listed fish, with the exception of one 
pile per day being ``proofed'' with an impact hammer. Proofing requires 
approximately 20-40 blows per pile which equates to approximately 15-20 
seconds of impact hammering per day. This action would also serve to 
reduce impacts to marine mammals.

Soft start to pile driving activities

    A ``soft start'' technique would be used at the beginning of each 
pile installation to allow any marine mammal that may be in the 
immediate area to leave before impact piling reaches full energy. The 
soft start requires contractors to initiate noise from vibratory 
hammers for 15 seconds at reduced energy followed by 1-minute waiting 
period. The procedure would be repeated two additional times. Due to 
the short duration of impact pile driving (20 seconds), the traditional 
ramp-up requirement for impact pile driving does not apply as it would 
actually increase the duration of noise emitted into the environment 
and monitoring should effectively detect marine mammals within or near 
the proposed impact pile driving shut down of 100 ft (30 m). If any 
marine mammal is sighted within or approaching this shut down zone 
prior to pile-driving, Caltrans would delay pile-driving until the 
animal has moved outside and on a path away from such zone or after 15 
minutes have elapsed since the last sighting of the marine mammal.

Marine Mammal Monitoring

    Safety zone monitoring would be conducted during all active pile 
driving. Monitoring of the 100 ft (30 m) safety zone would be conducted 
by qualified, NMFS approved marine mammal observers (MMOs). Impact pile 
driving would not begin until the 100 ft safety zone is clear of marine 
mammals and would be stopped in the event that marine mammals enter the 
safety zone. For all pile driving, MMOs would begin monitoring at least 
30 minutes prior to the commencement of pile driving and could conduct 
monitoring from small boats, as observation from a higher vantage point 
may not be practical. MMOs would remain 50 yards from swimming 
pinnipeds in accordance with NMFS marine mammal viewing guidelines 
(https://swr.nmfs.noaa.gov/psd/rookeryhaulouts/CASEALVIEWBROCHURE.pdf). 
This would prevent additional harassment to pinnipeds from the vessel. 
If a land based monitoring point can be found, MMOs would be stationed 
here. Observations would be made with binoculars during daylight hours. 
Data on all observed marine mammals would be recorded and include 
information such as species, numbers, time of observation, location, 
and behavior.

Acoustic Monitoring

    Monitors would be present to conduct hydro-acoustic monitoring, in 
order to empirically establish the 190 dB RMS (impulse) safety zone and 
behavioral harassment zones. Field measurements of sound pressure 
levels would be recorded and analyzed. A more detailed marine mammal 
monitoring plan and hydro-acoustic monitoring plan would be made by the 
monitoring contractor prior to the start of the Antioch Bridge seismic 
retrofit.

Reporting

    NMFS would be notified 2 weeks prior to the initiation of proposed 
work. Weekly monitoring reports would be sent to NMFS and include 
information such as species, numbers, time of observation, location, 
and behavior. Additionally, the report would include an assessment of 
the number of California sea lions and harbor seals that may have been 
harassed as a result of pile driving activity, based on direct 
observation of sea lions and harbor seals observed passing through the 
area. Should the acoustic monitoring reveal noise level isopleths 
different than those described here, a modification to the safety zone 
reflecting those data would occur.

Preliminary Determination

    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that pile driving associated with 
the Anitoch Bridge Seismic Retrofit Project would result in the 
incidental take of small numbers of marine mammals, by Level B 
harassment only, and that the total taking would have a negligible 
impact on the affected species or stocks. No subsistence hunting of 
marine mammals occurs in the region; therefore, no impact on the 
availability of a species or stock for subsistence use would occur.

Endangered Species Act (ESA)

    On January 26, 2009, NMFS received a request from Caltrans' to 
initiate consultation under section 7 of the ESA on its proposed 
Antioch Bridge Seismic Retrofit Project. NMFS concluded consultation on 
this action on July 13, 2009 and issued an incidental take statement 
authorizing the take of listed steelhead and green sturgeon. No ESA-
listed marine mammal species occur within the action area; therefore, 
none would be affected.

National Environmental Policy Act (NEPA)

    NOAA Administrative Order Series 216-6, May 20, 1999 (NAO), 
identifies issuance of IHAs as a type of Federal action that may be 
categorically excluded from preparation of an environmental assessment 
or environmental impact statement. In determining whether a categorical 
exclusion (CE) is appropriate for a given IHA, NMFS must consider: (1) 
factors listed in Section 5.05b of the NAO regarding prior analysis for 
the ``same'' action; (2) context and intensity of impacts, as defined 
in 40 CFR 1508.27; and (3) factors listed in Section 5.05c of the NAO 
regarding exceptions to CEs. NMFS has prepared, supplemented, or 
adopted numerous EAs leading to Findings of No Significant Impact 
(FONSIs) for pile driving activities similar to the proposed activity, 
including ones for Caltrans' projects which involved driving larger 
piles in

[[Page 67861]]

the northern section of the Bay where pinniped and cetacean species are 
more abundant. Based on these previous NEPA analyses and the analysis 
contained within this notice, NMFS has determined that issuance of a 
one-year IHA to Caltrans for the taking, by Level B harassment only, 
incidental to the Antioch Bridge Seismic Retrofit project does not have 
the potential to result in any significant changes to the human 
environment. Therefore, the issuance of an IHA to Caltrans for the 
specified activity falls under the category of those actions which can 
be categorically excluded from the need to prepare an Environmental 
Assessment or Environmental Impact Statement.

    Dated: December 14, 2009.
Helen M. Golde,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. E9-30179 Filed 12-18-09; 8:45 am]
BILLING CODE 3510-22-S