[Federal Register Volume 81, Number 101 (Wednesday, May 25, 2016)]
[Notices]
[Pages 33217-33242]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-12299]
-----------------------------------------------------------------------
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XE490
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the San Francisco Ferry Terminal
Expansion Project, South Basin Improvements Project
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments.
-----------------------------------------------------------------------
SUMMARY: NMFS has received a request from the San Francisco Bay Area
Water Emergency Transportation Authority (WETA) for authorization to
take marine mammals incidental to construction activities as part of a
ferry terminal expansion and improvements project. Pursuant to the
Marine Mammal Protection Act (MMPA), NMFS is requesting public comment
on its proposal to issue an incidental harassment authorization (IHA)
to WETA to incidentally take marine mammals, by Level B harassment
only, during the specified activity.
DATES: Comments and information must be received no later than June 24,
2016.
ADDRESSES: Comments on this proposal should be addressed to Jolie
Harrison, Chief, Permits and Conservation Division, Office of Protected
Resources, National Marine Fisheries Service. Physical comments should
be sent to 1315 East-West Highway, Silver Spring, MD 20910, and
electronic comments should be sent to [email protected].
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or
[[Page 33218]]
received after the end of the comment period. Comments received
electronically, including all attachments, must not exceed a 25-
megabyte file size. Attachments to electronic comments will be accepted
in Microsoft Word or Excel or Adobe PDF file formats only. All comments
received are a part of the public record and will generally be posted
to the Internet at www.nmfs.noaa.gov/pr/permits/incidental/construction.html without change. All personal identifying information
(e.g., name, address) voluntarily submitted by the commenter may be
publicly accessible. Do not submit confidential business information or
otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Laura McCue, Office of Protected
Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
Availability
An electronic copy of WETA's application and supporting documents,
as well as a list of the references cited in this document, may be
obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/construction.html. In case of problems accessing these
documents, please call the contact listed above.
National Environmental Policy Act
NMFS is currently conducting an analysis, pursuant to National
Environmental Policy Act (NEPA), to determine whether or not this
proposed activity may have a significant effect on the human
environment. This analysis will be completed prior to the issuance or
denial of this proposed IHA.
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 by U.S.
citizens who engage in a specified activity (other than commercial
fishing) within a specified area, the incidental, but not intentional,
taking of small numbers of marine mammals, providing that certain
findings are made and the necessary prescriptions are established.
The incidental taking of small numbers of marine mammals may be
allowed only if NMFS (through authority delegated by the Secretary)
finds that the total taking by the specified activity during the
specified time period will (i) have a negligible impact on the species
or stock(s) and (ii) not have an unmitigable adverse impact on the
availability of the species or stock(s) for subsistence uses (where
relevant). Further, the permissible methods of taking and requirements
pertaining to the mitigation, monitoring and reporting of such taking
must be set forth, either in specific regulations or in an
authorization.
The allowance of such incidental taking under section 101(a)(5)(A),
by harassment, serious injury, death, or a combination thereof,
requires that regulations be established. Subsequently, a Letter of
Authorization may be issued pursuant to the prescriptions established
in such regulations, providing that the level of taking will be
consistent with the findings made for the total taking allowable under
the specific regulations. Under section 101(a)(5)(D), NMFS may
authorize such incidental taking by harassment only, for periods of not
more than one year, pursuant to requirements and conditions contained
within an IHA. The establishment of prescriptions through either
specific regulations or an authorization requires notice and
opportunity for public comment.
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.'' Except with respect to certain activities
not pertinent here, section 3(18) of 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 February 8, 2016, we received a request from WETA for
authorization of the taking, by level B harassment only, of marine
mammals, incidental to pile driving in association with the San
Francisco Ferry Terminal Expansion Project, South Basin Improvements
Project in San Francisco Bay, California. That request was modified to
include additional species and additional monitoring and mitigation
measures on March 28, 2016 and May 2, 2016, and a final version, which
we deemed adequate and complete, was submitted on May 13, 2016, which
included revised take numbers and additional mitigation measures. In-
water work associated with the project is expected to be completed
within 23 months. This proposed IHA is for the first phase of
construction activities (July 1, 2016-December 31, 2016).
The use of both vibratory and impact pile driving is expected to
produce underwater sound at levels that have the potential to result in
behavioral harassment of marine mammals. Seven species of marine
mammals have the potential to be affected by the specified activities:
Harbor seal (Phoca vitulina), California sea lion (Zalophus
californianus), Northern elephant seal (Mirounga angustirostris),
Northern fur seal (Callorhinus ursinus), harbor porpoise (Phocoena
phocoena), gray whale (Eschrichtius robustus), and bottlenose dolphin
(Tursiops truncatus). These species may occur year round in the action
area.
Similar construction and pile driving activities in San Francisco
Bay have been authorized by NMFS in the past. These projects include
construction activities at the Exploratorium (75 FR 66065), pier 36 (77
FR 20361), and the Oakland Bay Bridge (71 FR 26750; 72 FR 25748; 74 FR
41684; 76 FR 7156; 78 FR 2371; 79 FR 2421; and 80 FR 43710).
Description of the Specified Activity
Overview
The San Francisco Bay Area Water Emergency Transportation Authority
(WETA) is expanding berthing capacity at the Downtown San Francisco
Ferry Terminal (Ferry Terminal), located at the San Francisco Ferry
Building (Ferry Building), to support existing and future planned water
transit services operated on San Francisco Bay by WETA and WETA's
emergency operations.
The Downtown San Francisco Ferry Terminal Expansion Project would
eventually include phased construction of three new water transit gates
and overwater berthing facilities, in addition to supportive landside
improvements, such as additional passenger waiting and queuing areas,
circulation improvements, and other water transit-related amenities.
The new gates and other improvements would be designed to accommodate
future planned water transit services between Downtown San Francisco
and Antioch, Berkeley, Martinez, Hercules, Redwood City, Richmond, and
Treasure Island, as well as emergency operation needs. According to
current planning and operating assumptions, WETA will not require all
three new gates (Gates A, F, and G) to support existing and new
services immediately. As a result, WETA is planning that project
construction will be phased. The first phase will include construction
of Gates
[[Page 33219]]
F and G, as well as other related improvements in the South Basin.
Dates and Duration
The total project is expected to require a maximum of 130 days of
in-water pile driving. The project may require up to 23 months for
completion; with a maximum of 106 days for pile driving in the first
year. In-water activities are limited to occur between July 1 and
November 30, 2016 and June 1 through November 30, 2017. If in-water
work will extend beyond the effective dates of the IHA, a second IHA
application will be submitted by WETA. This proposed authorization
would be effective from July 1, 2016 to December 31, 2016.
Specific Geographic Region
The San Francisco ferry terminal is located in the western shore of
San Francisco Bay (see Figure 1 of WETA's application). The ferry
terminal is five blocks north of the San Francisco Oakland Bay Bridge.
More specifically, the south basin of the ferry terminal is located
between Pier 14 and the ferry plaza. San Francisco Bay and the adjacent
Sacramento-San Joaquin Delta make up one of the largest estuarine
systems on the continent. The Bay has undergone extensive
industrialization, but remains an important environment for healthy
marine mammal populations year round. The area surrounding the proposed
activity is an intertidal landscape with heavy industrial use and boat
traffic.
Detailed Description of Activities
The project supports existing and future planned water transit
services operated by WETA, and regional policies to encourage transit
uses. Furthermore, the project addresses deficiencies in the
transportation network that impede water transit operation, passenger
access, and passenger circulation at the Ferry Terminal.
The project includes construction of two new water transit gates
and associated overwater berthing facilities, in addition to supportive
improvements, such as additional passenger waiting and queuing areas
and circulation improvements in a 7.7-acre area (see Figure 1 in the
WETA's application, which depicts the project area, and Figure 2, which
depicts the project improvements). The project includes the following
elements: (1) Removal of portions of existing deck and pile
construction (portions will remain as open water, and other portions
will be replaced); (2) Construction of two new gates (Gates F and G);
(3) Relocation of an existing gate (Gate E); and (4) Improved passenger
boarding areas, amenities, and circulation, including extending the
East Bayside Promenade along Gates E, F, and G; strengthening the South
Apron of the Agriculture Building; creating the Embarcadero Plaza; and
installing weather protection canopies for passenger queuing.
Implementation of the project improvements will result in a change
in the type and area of structures over San Francisco Bay. In some
areas, structures will be demolished and then rebuilt. The project will
require both the removal and installation of piles as summarized in
Table 1. Demolition and construction could be completed within 23
months.
Table 1--Summary of Pile Removal and Installation
----------------------------------------------------------------------------------------------------------------
Number of piles/
Project element Pile diameter Pile type Method schedule
----------------------------------------------------------------------------------------------------------------
Demolition in the South Basin... 12 to 18 inches... Wood and concrete. Pull or cut off 2 350 piles/30 days
feet below mud 2016.
line.
Removal of Dolphin Piles in the 36 inches......... Steel: 140 to 150 Pull out.......... Four dolphin
South Basin. feet in length. piles.
Embarcadero Plaza and East 24 or 36 inches... Steel: 135 to 155 Impact or 220 24- or 36-inch
Bayside Promenade. feet in length. Vibratory Driver. piles/65 days
2016.
Gates E, F, and G Dolphin Piles. 36 inches......... Steel: 145 to 155 Impact or 14 total: Two at
feet in length. Vibratory Driver. each of the
floats for
protection; two
between each of
the floats; and
four adjacent to
the breakwater.
Gates F and G Guide Piles....... 36 inches......... Steel: 140 to 150 Impact or 12 (6 per gate)/12
feet in length. Vibratory Driver. days 2017.
Gate E Guide Piles.............. 36 inches......... Steel: 145 to 155 Vibratory Driver Six piles will be
feet in length. for removal, may removed and
be reinstalled reinstalled/12
with an impact days 2017.
driver.
Fender Piles.................... 14 inches......... Polyurethane- Impact or 38/10 days 2016.
coated pressure- Vibratory Driver.
treated wood; 64
feet in length.
----------------------------------------------------------------------------------------------------------------
Removal of Existing Facilities
As part of the project, the remnants of Pier 2 will be demolished
and removed. This consists of approximately 21,000 square feet of
existing deck structure supported by approximately 350 wood and
concrete piles. In addition, four dolphin piles will be removed.
Demolition will be conducted from barges. Two barges will be required:
One for materials storage, and one outfitted with demolition equipment
(crane, clamshell bucket for pulling of piles, and excavator for
removal of the deck). Diesel-powered tug boats will bring the barges to
the project area, where they will be anchored. Piles will be removed by
either cutting them off two feet below the mud line or pulling the
pile.
Construction of Gates and Berthing Structures
The new gates (Gates F and G) will be built similarly. Each gate
will be designed with an entrance portal--a prominent doorway
physically separating the berthing structures from the surrounding
area. Berthing structures will be provided for each new gate,
consisting of floats, gangways, and guide piles. The steel floats will
be approximately 42 feet wide by 135 feet long. The steel truss
gangways will be approximately 14 feet wide and 105 feet long. The
gangway will be designed to rise and fall with tidal variations while
meeting Americans with Disabilities Act
[[Page 33220]]
(ADA) requirements. The gangway and the float will be designed with
canopies, consistent with the current design of existing Gates B and E.
The berthing structures will be fabricated off site and floated to the
project area by barge. Six steel guide piles will be required to secure
each float in place. In addition, dolphin piles may be used at each
berthing structure to protect against the collision of vessels with
other structures or vessels. A total of up to 14 dolphin piles may be
installed.
Chock-block fendering will be added along the East Bayside
Promenade, to adjacent structures to protect against collision. The
chock-block fendering will consist of square, 12-inch-wide,
polyurethane-coated, pressure-treated wood blocks that are connected
along the side of the adjacent pier structure, and supported by
polyurethane-coated, pressure-treated wood piles. In addition, the
existing Gate E float will be moved 43 feet to the east, to align with
the new gates and East Bayside Promenade. The existing six 36-inch-
diameter steel guide piles will be removed using vibratory extraction,
and reinstalled to secure the Gate E float in place. Because of Gate
E's new location, to meet ADA requirements, the existing 90-foot-long
steel truss gangway will be replaced with a longer, 105-foot-long
gangway.
Passenger Boarding and Circulation Areas
Several improvements will be made to passenger boarding and
circulation areas. New deck and pile-supported structures will be
built.
An Embarcadero Plaza, elevated approximately 3 to 4 feet
above current grade, will be created. The Embarcadero Plaza will
require new deck and pile construction to fill an open-water area and
replace existing structures that do not comply with Essential
Facilities requirements.
The East Bayside Promenade will be extended to create
continuous pedestrian access to Gates E, F, and G, as well as to meet
public access and pedestrian circulation requirements along San
Francisco Bay. It will extend approximately 430 feet in length, and
will provide an approximately 25-foot-wide area for pedestrian
circulation and public access along Gates E, F, and G. The perimeter of
the East Bayside Promenade will also include a curbed edge with a
guardrail.
Short access piers, approximately 30 feet wide and 45 feet
long, will extend from the East Bayside Promenade to the portal for
each gate.
The South Apron of the Agriculture Building will be
upgraded to temporarily support access for passenger circulation.
Depending on their condition, as determined during Final Design, the
piles supporting this apron may need to be strengthened with steel
jackets.
Two canopies will be constructed along the East Bayside
Promenade: One between Gates E and F, and one between Gates F and G.
Each of the canopies will be 125 feet long and 20 feet wide. Each
canopy will be supported by four columns at 35 feet on center, with 10-
foot cantilevers at either end. The canopies will be constructed of
steel and glass, and will include photovoltaic cells.
The new deck will be constructed on the piles, using a system of
beam-and-flat-slab-concrete construction, similar to what has been
built in the Ferry Building area. The beam-and-slab construction will
be either precast or cast-in-place concrete (or a combination of the
two), and approximately 2.5 feet thick. Above the structure, granite
paving or a concrete topping slab will provide a finished pedestrian
surface.
The passenger facilities, amenities, and public space
improvements--such as the entrance portals, canopy structures,
lighting, guardrails, and furnishings--will be surface-mounted on the
pier structures after the new construction and repair are complete. The
canopies and entrance portals will be constructed offsite, delivered to
the site, craned into place by barge, and assembled onsite. The glazing
materials, cladding materials, granite pavers, guardrails, and
furnishings will be assembled onsite.
Dredging Requirements
The side-loading vessels require a depth of 12.5 feet below mean
lower low water (MLLW) on the approach and in the berthing area. Based
on a bathymetric survey conducted in 2015, it is estimated that the new
Gates F and G will require dredging to meet the required depths. The
expected dredging volumes are presented in Table 2. These estimates are
based on dredging the approach areas to 123.5 feet below MLLW, and 2
feet of overdredge depth, to account for inaccuracies in dredging
practices. The dredging will take approximately 2 months.
Table 2--Summary of Dredging Requirements
------------------------------------------------------------------------
Dredging element Summary
------------------------------------------------------------------------
Initial Dredging
Gate F............................. 0.78 acre/6,006 cubic yards.
Gate G............................. 1.64 acres/14,473 cubic yards.
Total for Gates F and G............ 2.42 acres/20,479 cubic yards.
Staging............................ On barges.
Typical Equipment.................. Clamshell dredge on barge;
disposal barge; survey boat.
Duration........................... 2 months.
Maintenance Dredging
Gates F and G...................... 5,000 to 10,000 cubic yards.
Frequency.......................... Every 3 or 4 years.
------------------------------------------------------------------------
Based on observed patterns of sediment accumulation in the Ferry
Terminal area, significant sediment accumulation will not be expected,
because regular maintenance dredging is not currently required to
maintain operations at existing Gates B and E. However, some dredging
will likely be required on a regular maintenance cycle beneath the
floats at Gates F and G, due to their proximity to the Pier 14
breakwater. It is expected that maintenance dredging will be required
every 3 to 4 years, and will require removal of approximately 5,000 to
10,000 cubic yards of material.
Dredging and disposal of dredged materials will be conducted in
cooperation with the San Francisco Dredged Materials Management Office
(DMMO), including development of a sampling plan, sediment
characterization, a sediment removal plan, and disposal in accordance
with the Long-Term Management Strategy for San Francisco Bay to ensure
beneficial reuse, as appropriate. DMMO consultation is expected to
begin in early 2016. Based on the results of the sediment analysis, the
alternatives for
[[Page 33221]]
placement of dredged materials will be evaluated, including disposal at
the San Francisco Deep Ocean Disposal Site, disposal at an upland
facility, or beneficial reuse. Selection of the disposal site will be
reviewed and approved by the DMMO.
Description of Marine Mammals in the Area of the Specified Activity
There are seven marine mammal species which may inhabit or may
likely transit through the waters nearby the Ferry Terminal, and which
are expected to potentially be taken by the specified activity. These
include the Pacific harbor seal (Phoca vitulina), California sea lion
(Zalophus californianus), Northern Elephant seal (Mirounga
angustirostris), Northern fur seal (Callorhinus ursinus), harbor
porpoise (Phocoena phocoena), gray whale (Eschrichtius robustus), and
bottlenose dolphin (Tursiops truncatus). Multiple additional marine
mammal species may occasionally enter the activity area in San
Francisco Bay but would not be expected to occur in shallow nearshore
waters of the action area. Guadalupe fur seals (Arctocephalus
townsendi) generally do not occur in San Francisco Bay; however, there
have been recent sightings of this species due to the El Ni[ntilde]o
event. Only single individuals of this species have occasionally been
sighted inside San Francisco Bay, and their presence near the action
area is considered unlikely. No takes are requested for this species,
and mitigation measures such as a shutdown zone will be in effect for
this species if observed approaching the Level B harassment zone.
Although it is possible that a humpback whale (Megaptera navaeangliae)
may enter San Francisco Bay and find its way into the project area
during construction activities, their occurrence is unlikely. No takes
are requested for this species, and mitigation measures such as a delay
and shutdown procedure will be in effect for this species if observed
approaching the Level B harassment zone. Table 3 lists the marine
mammal species with expected potential for occurrence in the vicinity
of the SF Ferry terminal during the project timeframe and summarizes
key information regarding stock status and abundance. Taxonomically, we
follow Committee on Taxonomy (2014). Please see NMFS' Stock Assessment
Reports (SAR), available at www.nmfs.noaa.gov/pr/sars, for more
detailed accounts of these stocks' status and abundance. Please also
refer to NMFS' Web site (www.nmfs.noaa.gov/pr/species/mammals) for
generalized species accounts.
Table 3--Marine Mammals Potentially Present in the Vicinity of San Francisco Ferry Terminal
----------------------------------------------------------------------------------------------------------------
Stock abundance Relative
ESA/MMPA (CV, Nmin, most occurrence in
Species Stock Status; recent PBR 3 Strait of Juan
strategic (Y/N) abundance de Fuca; season
1 survey) 2 of occurrence
----------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Phocoenidae
(porpoises)
Harbor porpoise............. San Francisco- -; N........... 9,886 (0.51; 66 Common.
Russian River. 6,625; 2011).
----------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Delphinidae
(dolphins)
Bottlenose dolphin 5........ California -; N........... 323 (0.13; 290; 2.4 Rare.
coastal. 2005).
----------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
----------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae
Gray whale.................. Eastern N. -; N........... 20,990 (0.05; 624 Rare.
Pacific. 20,125; 2011).
----------------------------------------------------------------------------------------------------------------
Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
Family Balaenopteridae
Humpback whale.............. California/ E; S........... 1,918.......... 11 Unlikely.
Oregon/
Washington
stock.
----------------------------------------------------------------------------------------------------------------
Order Carnivora--Superfamily Pinnipedia
----------------------------------------------------------------------------------------------------------------
Family Otariidae (eared
seals and sea lions)
California sea lion......... U.S............ -; N........... 296,750 (n/a; 9,200 Common.
153,337; 2011).
Guadalupe fur seal 5........ Mexico to T; S........... 7,408 (n/a; 91 Unlikely.
California. 3,028; 1993).
Northern fur seal........... California -; N........... 14,050 (n/a; 451 Unlikely.
stock. 7,524; 2013).
----------------------------------------------------------------------------------------------------------------
Family Phocidae (earless
seals)
Harbor seal................. California..... -; N........... 30,968 (n/a; 1,641 Common; Year-
27,348; 2012). round
resident.
Northern elephant seal...... California -; N........... 179,000 (n/a; 4,882 Rare.
breeding stock. 81,368; 2010).
----------------------------------------------------------------------------------------------------------------
1 ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is
not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one
for which the level of direct human-caused mortality exceeds PBR (see footnote 3) or which is determined to be
declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
[[Page 33222]]
2 CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not
applicable. For certain stocks, abundance estimates are actual counts of animals and there is no associated
CV. The most recent abundance survey that is reflected in the abundance estimate is presented; there may be
more recent surveys that have not yet been incorporated into the estimate.
3 Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural
mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its
optimum sustainable population size (OSP).
4 These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from
all sources combined (e.g., commercial fisheries, subsistence hunting, ship strike). Annual M/SI often cannot
be determined precisely and is in some cases presented as a minimum value. All values presented here are from
the draft 2015 SARs (www.nmfs.noaa.gov/pr/sars/draft.htm).
5 Abundance estimates for these stocks are greater than eight years old and are therefore not considered
current. PBR is considered undetermined for these stocks, as there is no current minimum abundance estimate
for use in calculation. We nevertheless present the most recent abundance estimates and PBR values, as these
represent the best available information for use in this document.
Below, for those species that are likely to be taken by the
activities described, we offer a brief introduction to the species and
relevant stock as well as available information regarding population
trends and threats, and describe any information regarding local
occurrence.
Harbor Seal
The Pacific harbor seal is one of five subspecies of Phoca
vitulina, or the common harbor seal. There are five species of harbor
seal in the Pacific EEZ: (1) California stock; (2) Oregon/Washington
coast stock; (3) Washington Northern inland waters stock; (4) Southern
Puget Sound stock; and (5) Hood Canal stock. Only the California stock
occurs in the action area and is analyzed in this document. The current
abundance estimate for this stock is 30,968. This stock is not
considered strategic or designated as depleted under the MMPA and is
not listed under the ESA. PBR is 1,641 animals per year. The average
annual rate of incidental commercial fishery mortality (30 animals) is
less than 10% of the calculated PBR (1,641 animals); therefore, fishery
mortality is considered insignificant (Allen and Angliss, 2013).
Although generally solitary in the water, harbor seals congregate
at haulouts to rest, socialize, breed, molt. Habitats used as haul-out
sites include tidal rocks, bayflats, sandbars, and sandy beaches
(Zeiner et al., 1990). Haul-out sites are relatively consistent from
year-to-year (Kopec and Harvey, 1995), and females have been recorded
returning to their own natal haul-out when breeding (Cunningham et al.,
2009). Long-term monitoring studies have been conducted at the largest
harbor seal colonies in Point Reyes National Seashore and Golden Gate
National Recreation Area since 1976. Castro Rocks and other haulouts in
San Francisco Bay are part of the regional survey area for this study
and have been included in annual survey efforts. Between 2007 and 2012,
the average number of adults observed ranged from 126 to 166 during the
breeding season (March through May), and from 92 to 129 during the
molting season (June through July) (Truchinski et al., 2008; Flynn et
al., 2009; Codde et al., 2010; Codde et al., 2011; Codde et al., 2012;
Codde and Allen, 2015). Marine mammal monitoring at multiple locations
inside San Francisco Bay was conducted by Caltrans from May 1998 to
February 2002, and determined that at least 500 harbor seals populate
San Francisco Bay (Green et al., 2002). This estimate is consistent
with previous seal counts in the San Francisco Bay, which ranged from
524 to 641 seals from 1987 to 1999 (Goals Project, 2000). Although
harbor seals haul-out at approximately 20 locations in San Francisco
Bay, there are three locations that serve as primary locations: Mowry
Slough in the south Bay, Corte Madera Marsh and Castro Rocks in the
north Bay, and Yerba Buena Island in the central Bay (Grigg, 2008;
Gibble, 2011). The main pupping areas in the San Francisco Bay are at
Mowry Slough and Castro Rocks (Caltrans, 2012). Pupping season for
harbor seals in San Francisco Bay spans from approximately March 15
through May 31, with pup numbers generally peaking in late April or May
(Caretta et al 2015). Births of harbor seals have not been observed at
Corte Madera Marsh and Yerba Buena Island, but a few pups have been
seen at these sites. Harbor seals forage in shallow waters on a variety
of fish and crustaceans that are present throughout much of San
Francisco Bay, and therefore could occasionally be found foraging in
the action area as well.
California Sea Lion
California sea lions range all along the western border of North
America. The breeding areas of the California sea lion are on islands
located in southern California, western Baja California, and the Gulf
of California (Allen and Angliss 2015). Although California sea lions
forage and conduct many activities in the water, they also use haul-
outs. California sea lions breed in Southern California and along the
Channel Islands during the spring. The current population estimate for
California sea lions is 296,750 animals. This species is not considered
strategic under the MMPA, and is not designated as depleted. This
species is also not listed under the ESA. PBR is 9,200 (Caretta et al,
2015). Interactions with fisheries, boat collisions, human
interactions, and entanglement are the main threats to this species
(Caretta et al 2015).
El Ni[ntilde]o affects California sea lion populations, with
increased observations and strandings of this species in the area.
Current observations of this species in CA have increased significantly
over the past few years. Additionally, as a result of the large numbers
of sea lion strandings in 2013, NOAA declared an unusual mortality
event (UME). Although the exact causes of this UME are unknown, two
hypotheses meriting further study include nutritional stress of pups
resulting from a lack of forage fish available to lactating mothers and
unknown disease agents during that time period.
In San Francisco Bay, sea lions haul out primarily on floating K
docks at Pier 39 in the Fisherman's Wharf area of the San Francisco
Marina. The Pier 39 haul out is approximately 1.5 miles from the
project vicinity. The Marine Mammal Center (TMMC) in Sausalito,
California has performed monitoring surveys at this location since
1991. A maximum of 1,706 sea lions was seen hauled out during one
survey effort in 2009 (TMMC, 2015). Winter numbers are generally over
500 animals (Goals Project, 2000). In August to September, counts
average from 350 to 850 (NMFS, 2004). Of the California sea lions
observed, approximately 85 percent were male. No pupping activity has
been observed at this site or at other locations in the San Francisco
Bay (Caltrans, 2012). The California sea lions usually frequent Pier 39
in August after returning from the Channel Islands (Caltrans, 2013). In
addition to the Pier 39 haul-out, California sea lions haul out on
buoys and similar structures throughout San Francisco Bay. They mainly
are seen swimming off the San Francisco and Marin shorelines within San
Francisco Bay, but may occasionally enter the project area to forage.
Although there is little information regarding the foraging
behavior of the California sea lion in the San Francisco Bay, they have
been observed foraging
[[Page 33223]]
on a regular basis in the shipping channel south of Yerba Buena Island.
Foraging grounds have also been identified for pinnipeds, including sea
lions, between Yerba Buena Island and Treasure Island, as well as off
the Tiburon Peninsula (Caltrans, 2001).
Northern Elephant Seal
Northern elephant seals breed and give birth in California (U.S.)
and Baja California (Mexico), primarily on offshore islands (Stewart et
al. 1994), from December to March (Stewart and Huber 1993). Although
movement and genetic exchange continues between rookeries, most
elephant seals return to natal rookeries when they start breeding
(Huber et al. 1991). The California breeding population is now
demographically isolated from the Baja California population, and is
the only stock to occur near the action area. The current abundance
estimate for this stock is 179,000 animals, with PBR at 4,882 animals
(Caretta et al 2015). The population is reported to have grown at 3.8%
annually since 1988 (Lowry et al. 2014). Fishery interactions and
marine debris entanglement are the biggest threats to this species
(Caretta et al 2015). Northern elephant seals are not listed under the
Endangered Species Act, nor are they designated as depleted, or
considered strategic under the MMPA.
Northern elephant seals are common on California coastal mainland
and island sites where they pup, breed, rest, and molt. The largest
rookeries are on San Nicolas and San Miguel islands in the Northern
Channel Islands. In the vicinity of San Francisco Bay, elephant seals
breed, molt, and haul out at A[ntilde]o Nuevo Island, the Farallon
Islands, and Point Reyes National Seashore (Lowry et al., 2014). Adults
reside in offshore pelagic waters when not breeding or molting.
Northern elephant seals haul out to give birth and breed from December
through March, and pups remain onshore or in adjacent shallow water
through May, when they may occasionally make brief stops in San
Francisco Bay (Caltrans, 2015b). The most recent sighting was in 2012
on the beach at Clipper Cove on Treasure Island, when a healthy
yearling elephant seal hauled out for approximately one day.
Approximately 100 juvenile northern elephant seals strand in San
Francisco Bay each year, including individual strandings at Yerba Buena
Island and Treasure Island (fewer than 10 strandings per year)
(Caltrans, 2015b). When pups of the year return in the late summer and
fall to haul out at rookery sites, they may also occasionally make
brief stops in San Francisco Bay.
Northern Fur Seal
Northern fur seals (Callorhinus ursinus) occur from southern
California north to the Bering Sea and west to the Okhotsk Sea and
Honshu Island, Japan. During the breeding season, approximately 74% of
the worldwide population is found on the Pribilof Islands in the
southern Bering Sea, with the remaining animals spread throughout the
North Pacific Ocean (Lander and Kajimura 1982). Of the seals in U.S.
waters outside of the Pribilofs, approximately one percent of the
population is found on Bogoslof Island in the southern Bering Sea, San
Miguel Island off southern California (NMFS 2007), and the Farallon
Islands off central California. Two separate stocks of northern fur
seals are recognized within U.S. waters: An Eastern Pacific stock and a
California stock (including San Miguel Island and the Farallon
Islands). Only the California breeding stock is considered here since
it is the only stock to occur near the action area. The current
abundance estimate for this stock is 14,050 and PBR is set at 451
animals (Caretta et al 2015). This stock has grown exponentially during
the past several years. Interaction with fisheries remains the top
threat to this species (Caretta et al, 2015). This stock is not
considered depleted or classified as strategic under the MMPA, and is
not listed under the ESA.
Harbor Porpoise
In the Pacific, harbor porpoise are found in coastal and inland
waters from Point Conception, California to Alaska and across to
Kamchatka and Japan (Gaskin 1984). Harbor porpoise appear to have more
restricted movements along the western coast of the continental U.S.
than along the eastern coast. Regional differences in pollutant
residues in harbor porpoise indicate that they do not move extensively
between California, Oregon, and Washington (Calambokidis and Barlow
1991). That study also showed some regional differences within
California (Allen and Angliss, 2014). Of the 10 stocks of Pacific
harbor porpoise, only the San Francisco-Russian River stock is
considered here since it is the only stock to occur near the action
area. This current abundance estimate for this stock is 9,886 animals,
with a PBR of 66 animals (Caretta et al 2015). Current population
trends are not available for this stock. The main threats to this stock
include fishery interactions. This stock is not designated as strategic
or considered depleted under the MMPA, and is not listed under the ESA.
Gray Whale
Once common throughout the Northern Hemisphere, the gray whale was
extinct in the Atlantic by the early 1700s. Gray whales are now only
commonly found in the North Pacific. Genetic comparisons indicate there
are distinct ``Eastern North Pacific'' (ENP) and ``Western North
Pacific'' (WNP) population stocks, with differentiation in both mtDNA
haplotype and microsatellite allele frequencies (LeDuc et al. 2002;
Lang et al. 2011a; Weller et al. 2013). Only the ENP stock occurs in
the action area and is considered in this document. The current
population estimate for this stock is 20,990 animals, with PBR at 624
animals (Caretta et al, 2015). The population size of the ENP gray
whale stock has increased over several decades despite an UME in 1999
and 2000 and has been relatively stable since the mid-1990s.
Interactions with fisheries, ship strikes, entanglement in marine
debris, and habitat degradation are the main concerns for the gray
whale population (Caretta et al 2015). This stock is not listed under
the ESA, and is not considered a strategic stock or designated as
depleted under the MMPA.
Bottlenose Dolphin
Bottlenose dolphins are distributed worldwide in tropical and warm-
temperate waters. In many regions, including California, separate
coastal and offshore populations are known (Walker 1981; Ross and
Cockcroft 1990; Van Waerebeek et al. 1990). There are genetic
differences between the populations; based on nuclear and mtDNA
analyses, there are no shared haplotypes between coastal and offshore
animals and significant genetic differentiation between the two
ecotypes was evident (Caretta et al 2008). California coastal
bottlenose dolphins are found within about one kilometer of shore
(Hansen, 1990; Carretta et al. 1998; Defran and Weller 1999) primarily
from Point Conception south into Mexican waters, at least as far south
as San Quintin, Mexico. Oceanographic events appear to influence the
distribution of animals along the coasts of California and Baja
California, Mexico, as indicated by El Ni[ntilde]o events. There are
three stocks of bottlenose dolphins in the Pacific: (1) California
coastal stock, (2) California, Oregon, and Washington offshore stock,
and (3) Hawaiian stock. Only the California coastal stock may occur in
the action area. The current stock abundance estimate for the
California
[[Page 33224]]
coastal stock is 323 animals, with PBR at 2.4 animals (Caretta et al
2008). Pollutant levels in California are a threat to this species, and
this stock may be vulnerable to disease outbreaks, particularly
morbillivirus (Caretta et al 2008). This stock is not listed under the
ESA, and is not considered strategic or designated as depleted under
the MMPA.
Potential Effects of the Specified Activity on Marine Mammals and Their
Habitat
This section includes a summary and discussion of the ways that
components of the specified activity (e.g., sound produced by pile
driving) may impact marine mammals and their habitat. The Estimated
Take by Incidental Harassment section later in this document will
include a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
section will include an analysis of how this specific activity will
impact marine mammals and will consider the content of this section,
the Estimated Take by Incidental Harassment section and the Proposed
Mitigation section to draw conclusions regarding the likely impacts of
this activity on the reproductive success or survivorship of
individuals and from that on the affected marine mammal populations or
stocks. In the following discussion, we provide general background
information on sound and marine mammal hearing before considering
potential effects to marine mammals from sound produced by vibratory
and impact pile driving.
Description of Sound Sources
Sound travels in waves, the basic components of which are
frequency, wavelength, velocity, and amplitude. Frequency is the number
of pressure waves that pass by a reference point per unit of time and
is measured in hertz (Hz) or cycles per second. Wavelength is the
distance between two peaks of a sound wave; lower frequency sounds have
longer wavelengths than higher frequency sounds and attenuate
(decrease) more rapidly in shallower water. Amplitude is the height of
the sound pressure wave or the `loudness' of a sound and is typically
measured using the decibel (dB) scale. A dB is the ratio between a
measured pressure (with sound) and a reference pressure (sound at a
constant pressure, established by scientific standards). It is a
logarithmic unit that accounts for large variations in amplitude;
therefore, relatively small changes in dB ratings correspond to large
changes in sound pressure. When referring to sound pressure levels
(SPLs; the sound force per unit area), sound is referenced in the
context of underwater sound pressure to 1 microPascal ([mu]Pa). One
pascal is the pressure resulting from a force of one newton exerted
over an area of one square meter. The source level (SL) represents the
sound level at a distance of 1 m from the source (referenced to 1
[mu]Pa). The received level is the sound level at the listener's
position. Note that all underwater sound levels in this document are
referenced to a pressure of 1 [mu]Pa and all airborne sound levels in
this document are referenced to a pressure of 20 [mu]Pa.
Root mean square (rms) is the quadratic mean sound pressure over
the duration of an impulse. Rms is calculated by squaring all of the
sound amplitudes, averaging the squares, and then taking the square
root of the average (Urick, 1983). Rms accounts for both positive and
negative values; squaring the pressures makes all values positive so
that they may be accounted for in the summation of pressure levels
(Hastings and Popper, 2005). This measurement is often used in the
context of discussing behavioral effects, in part because behavioral
effects, which often result from auditory cues, may be better expressed
through averaged units than by peak pressures.
When underwater objects vibrate or activity occurs, sound-pressure
waves are created. These waves alternately compress and decompress the
water as the sound wave travels. Underwater sound waves radiate in all
directions away from the source (similar to ripples on the surface of a
pond), except in cases where the source is directional. The
compressions and decompressions associated with sound waves are
detected as changes in pressure by aquatic life and man-made sound
receptors such as hydrophones.
Even in the absence of sound from the specified activity, the
underwater environment is typically loud due to ambient sound. Ambient
sound is defined as environmental background sound levels lacking a
single source or point (Richardson et al., 1995), and the sound level
of a region is defined by the total acoustical energy being generated
by known and unknown sources. These sources may include physical (e.g.,
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds
produced by marine mammals, fish, and invertebrates), and anthropogenic
sound (e.g., vessels, dredging, aircraft, construction). A number of
sources contribute to ambient sound, including the following
(Richardson et al., 1995):
Wind and waves: The complex interactions between wind and
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of
naturally occurring ambient noise for frequencies between 200 Hz and 50
kHz (Mitson, 1995). In general, ambient sound levels tend to increase
with increasing wind speed and wave height. Surf noise becomes
important near shore, with measurements collected at a distance of 8.5
km from shore showing an increase of 10 dB in the 100 to 700 Hz band
during heavy surf conditions.
Precipitation: Sound from rain and hail impacting the
water surface can become an important component of total noise at
frequencies above 500 Hz, and possibly down to 100 Hz during quiet
times.
Biological: Marine mammals can contribute significantly to
ambient noise levels, as can some fish and shrimp. The frequency band
for biological contributions is from approximately 12 Hz to over 100
kHz.
Anthropogenic: Sources of ambient noise related to human
activity include transportation (surface vessels and aircraft),
dredging and construction, oil and gas drilling and production, seismic
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise
typically dominates the total ambient noise for frequencies between 20
and 300 Hz. In general, the frequencies of anthropogenic sounds are
below 1 kHz and, if higher frequency sound levels are created, they
attenuate rapidly (Richardson et al., 1995). Sound from identifiable
anthropogenic sources other than the activity of interest (e.g., a
passing vessel) is sometimes termed background sound, as opposed to
ambient sound.
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activity may be a negligible addition to
[[Page 33225]]
the local environment or could form a distinctive signal that may
affect marine mammals.
The underwater acoustic environment at the ferry terminal is likely
to be dominated by noise from day-to-day port and vessel activities.
This is a highly industrialized area with high-use from small- to
medium-sized vessels, and larger vessel that use the nearby major
shipping channel. Underwater sound levels for water transit vessels,
which operate throughout the day from the San Francisco Ferry Building
ranged from 152 dB to 177 dB (WETA, 2003a). While there are no current
measurements of ambient noise levels at the ferry terminal, it is
likely that levels within the basin periodically exceed the 120 dB
threshold and, therefore, that the high levels of anthropogenic
activity in the basin create an environment far different from quieter
habitats where behavioral reactions to sounds around the 120 dB
threshold have been observed (e.g., Malme et al., 1984, 1988).
In-water construction activities associated with the project would
include impact pile driving and vibratory pile driving. The sounds
produced by these activities fall into one of two general sound types:
Pulsed and non-pulsed (defined in the following). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see
Southall et al., (2007) for an in-depth discussion of these concepts.
Pulsed sound sources (e.g., explosions, gunshots, sonic booms,
impact pile driving) produce signals that are brief (typically
considered to be less than one second), broadband, atonal transients
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and
occur either as isolated events or repeated in some succession. Pulsed
sounds are all characterized by a relatively rapid rise from ambient
pressure to a maximal pressure value followed by a rapid decay period
that may include a period of diminishing, oscillating maximal and
minimal pressures, and generally have an increased capacity to induce
physical injury as compared with sounds that lack these features.
Non-pulsed sounds can be tonal, narrowband, or broadband, brief or
prolonged, and may be either continuous or non-continuous (ANSI, 1995;
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals
of short duration but without the essential properties of pulses (e.g.,
rapid rise time). Examples of non-pulsed sounds include those produced
by vessels, aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, and active sonar systems (such as
those used by the U.S. Navy). The duration of such sounds, as received
at a distance, can be greatly extended in a highly reverberant
environment.
Impact hammers operate by repeatedly dropping a heavy piston onto a
pile to drive the pile into the substrate. Sound generated by impact
hammers is characterized by rapid rise times and high peak levels, a
potentially injurious combination (Hastings and Popper, 2005).
Vibratory hammers install piles by vibrating them and allowing the
weight of the hammer to push them into the sediment. Vibratory hammers
produce significantly less sound than impact hammers. Peak SPLs may be
180 dB or greater, but are generally 10 to 20 dB lower than SPLs
generated during impact pile driving of the same-sized pile (Oestman et
al., 2009). Rise time is slower, reducing the probability and severity
of injury, and sound energy is distributed over a greater amount of
time (Nedwell and Edwards, 2002; Carlson et al., 2005).
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals,
and exposure to sound can have deleterious effects. To appropriately
assess these potential effects, it is necessary to understand the
frequency ranges marine mammals are able to hear. Current data indicate
that not all marine mammal species have equal hearing capabilities
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and
Hastings, 2008). To reflect this, Southall et al. (2007) recommended
that marine mammals be divided into functional hearing groups based on
measured or estimated hearing ranges on the basis of available
behavioral data, audiograms derived using auditory evoked potential
techniques, anatomical modeling, and other data. The lower and/or upper
frequencies for some of these functional hearing groups have been
modified from those designated by Southall et al. (2007). The
functional groups and the associated frequencies are indicated below
(note that these frequency ranges do not necessarily correspond to the
range of best hearing, which varies by species):
Low frequency cetaceans (13 species of mysticetes):
Functional hearing is estimated to occur between approximately 7 Hz and
25 kHz (up to 30 kHz in some species), with best hearing estimated to
be from 100 Hz to 8 kHz (Watkins, 1986; Ketten, 1998; Houser et al.,
2001; Au et al., 2006; Lucifredi and Stein, 2007; Ketten et al., 2007;
Parks et al., 2007a; Ketten and Mountain, 2009; Tubelli et al., 2012);
Mid-frequency cetaceans (32 species of dolphins, six
species of larger toothed whales, and 19 species of beaked and
bottlenose whales): Functional hearing is estimated to occur between
approximately 150 Hz and 160 kHz with best hearing from 10 to less than
100 kHz (Johnson, 1967; White, 1977; Richardson et al., 1995; Szymanski
et al., 1999; Kastelein et al., 2003; Finneran et al., 2005a, 2009;
Nachtigall et al., 2005, 2008; Yuen et al., 2005; Popov et al., 2007;
Au and Hastings, 2008; Houser et al., 2008; Pacini et al., 2010, 2011;
Schlundt et al., 2011);
High frequency cetaceans (eight species of true porpoises,
six species of river dolphins, and members of the genera Kogia and
Cephalorhynchus; now considered to include two members of the genus
Lagenorhynchus on the basis of recent echolocation data and genetic
data [May-Collado and Agnarsson, 2006; Kyhn et al. 2009, 2010; Tougaard
et al. 2010]): Functional hearing is estimated to occur between
approximately 200 Hz and 180 kHz (Popov and Supin, 1990a,b; Kastelein
et al., 2002; Popov et al., 2005);
Phocid pinnipeds in Water: Functional hearing is estimated
to occur between approximately 75 Hz and 100 kHz with best hearing
between 1-50 kHz (M[oslash]hl, 1968; Terhune and Ronald, 1971, 1972;
Richardson et al., 1995; Kastak and Schusterman, 1999; Reichmuth, 2008;
Kastelein et al., 2009); and
Otariid pinnipeds in Water: Functional hearing is estimated to
occur between approximately 100 Hz and 48 kHz, with best hearing
between 2-48 kHz (Schusterman et al., 1972; Moore and Schusterman,
1987; Babushina et al., 1991; Richardson et al., 1995; Kastak and
Schusterman, 1998; Kastelein et al., 2005a; Mulsow and Reichmuth, 2007;
Mulsow et al., 2011a, b).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013).
As mentioned previously in this document, seven marine mammal
species (three cetaceans and four pinnipeds) may occur in the project
area. Of these three cetaceans, one is classified as a low-frequency
cetacean
[[Page 33226]]
(i.e. gray whale), one is classified as a mid-frequency cetacean (i.e.,
bottlenose dolphin), and one is classified as a high-frequency
cetaceans (i.e., harbor porpoise) (Southall et al., 2007).
Additionally, harbor seals, Northern fur seals, and Northern elephant
seals are classified as members of the phocid pinnipeds in water
functional hearing group while California sea lions are grouped under
the Otariid pinnipeds in water functional hearing group. A species'
functional hearing group is a consideration when we analyze the effects
of exposure to sound on marine mammals.
Acoustic Impacts
Please refer to the information given previously (Description of
Sound Sources) regarding sound, characteristics of sound types, and
metrics used in this document. Anthropogenic sounds cover a broad range
of frequencies and sound levels and can have a range of highly variable
impacts on marine life, from none or minor to potentially severe
responses, depending on received levels, duration of exposure,
behavioral context, and various other factors. The potential effects of
underwater sound from active acoustic sources can potentially result in
one or more of the following: Temporary or permanent hearing
impairment, non-auditory physical or physiological effects, behavioral
disturbance, stress, and masking (Richardson et al., 1995; Gordon et
al., 2004; Nowacek et al., 2007; Southall et al., 2007; Gotz et al.,
2009). The degree of effect is intrinsically related to the signal
characteristics, received level, distance from the source, and duration
of the sound exposure. In general, sudden, high level sounds can cause
hearing loss, as can longer exposures to lower level sounds. Temporary
or permanent loss of hearing will occur almost exclusively for noise
within an animal's hearing range. We first describe specific
manifestations of acoustic effects before providing discussion specific
to WETA's construction activities.
Richardson et al. (1995) described zones of increasing intensity of
effect that might be expected to occur, in relation to distance from a
source and assuming that the signal is within an animal's hearing
range. First is the area within which the acoustic signal would be
audible (potentially perceived) to the animal, but not strong enough to
elicit any overt behavioral or physiological response. The next zone
corresponds with the area where the signal is audible to the animal and
of sufficient intensity to elicit behavioral or physiological
responsiveness. Third is a zone within which, for signals of high
intensity, the received level is sufficient to potentially cause
discomfort or tissue damage to auditory or other systems. Overlaying
these zones to a certain extent is the area within which masking (i.e.,
when a sound interferes with or masks the ability of an animal to
detect a signal of interest that is above the absolute hearing
threshold) may occur; the masking zone may be highly variable in size.
We describe the more severe effects (i.e., permanent hearing
impairment, certain non-auditory physical or physiological effects)
only briefly as we do not expect that there is a reasonable likelihood
that WETA's activities may result in such effects (see below for
further discussion). Marine mammals exposed to high-intensity sound, or
to lower-intensity sound 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, 2005b). TS can be permanent (PTS), in which case
the loss of hearing sensitivity is not fully recoverable, or temporary
(TTS), in which case the animal's hearing threshold would recover over
time (Southall et al., 2007). Repeated sound exposure that leads to TTS
could cause PTS. In severe cases of PTS, there can be total or partial
deafness, while in most cases the animal has an impaired ability to
hear sounds in specific frequency ranges (Kryter, 1985).
When PTS occurs, there is physical damage to the sound receptors in
the ear (i.e., tissue damage), whereas TTS represents primarily tissue
fatigue and is reversible (Southall et al., 2007). In addition, other
investigators have suggested that TTS is within the normal bounds of
physiological variability and tolerance and does not represent physical
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to
constitute auditory injury.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals--PTS data exists only for a single harbor seal
(Kastak et al., 2008)--but are assumed to be similar to those in humans
and other terrestrial mammals. PTS typically occurs at exposure levels
at least several decibels above (a 40-dB threshold shift approximates
PTS onset; e.g., Kryter et al., 1966; Miller, 1974) that inducing mild
TTS (a 6-dB threshold shift approximates TTS onset; e.g., Southall et
al. 2007). Based on data from terrestrial mammals, a precautionary
assumption is that the PTS thresholds for impulse sounds (such as
impact pile driving pulses as received close to the source) are at
least 6 dB higher than the TTS threshold on a peak-pressure basis and
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher
than TTS cumulative sound exposure level thresholds (Southall et al.,
2007). Given the higher level of sound or longer exposure duration
necessary to cause PTS as compared with TTS, it is considerably less
likely that PTS could occur.
Non-auditory physiological effects or injuries that theoretically
might occur in marine mammals exposed to high level underwater sound or
as a secondary effect of extreme behavioral reactions (e.g., change in
dive profile as a result of an avoidance reaction) caused by exposure
to sound include neurological effects, bubble formation, resonance
effects, and other types of organ or tissue damage (Cox et al., 2006;
Southall et al., 2007; Zimmer and Tyack, 2007). WETA's activities do
not involve the use of devices such as explosives or mid-frequency
active sonar that are associated with these types of effects.
When a live or dead marine mammal swims or floats onto shore and is
incapable of returning to sea, the event is termed a ``stranding'' (16
U.S.C. 1421h(3)). Marine mammals are known to strand for a variety of
reasons, such as infectious agents, biotoxicosis, starvation, fishery
interaction, ship strike, unusual oceanographic or weather events,
sound exposure, or combinations of these stressors sustained
concurrently or in series (e.g., Geraci et al., 1999). However, the
cause or causes of most strandings are unknown (e.g., Best, 1982).
Combinations of dissimilar stressors may combine to kill an animal or
dramatically reduce its fitness, even though one exposure without the
other would not be expected to produce the same outcome (e.g., Sih et
al., 2004). For further description of stranding events see, e.g.,
Southall et al., 2006; Jepson et al., 2013; Wright et al., 2013.
1. Temporary threshold shift--TTS is the mildest form of hearing
impairment that can occur during exposure to sound (Kryter, 1985).
While experiencing TTS, the hearing threshold rises, and a sound must
be at a higher level in order to be heard. In terrestrial and marine
mammals, TTS can last from minutes or hours to days (in cases of strong
TTS). In many cases, hearing sensitivity recovers rapidly after
exposure to the sound ends. Few data on sound levels and durations
necessary to elicit mild TTS have been obtained for marine mammals, and
none of the data published at the time of this writing
[[Page 33227]]
concern TTS elicited by exposure to multiple pulses of sound.
Marine mammal hearing plays a critical role in communication with
conspecifics, and interpretation of environmental cues for purposes
such as predator avoidance and prey capture. Depending on the degree
(elevation of threshold in dB), duration (i.e., recovery time), and
frequency range of TTS, and the context in which it is experienced, TTS
can have effects on marine mammals ranging from discountable to
serious. For example, a marine mammal may be able to readily compensate
for a brief, relatively small amount of TTS in a non-critical frequency
range that occurs during a time where ambient noise is lower and there
are not as many competing sounds present. Alternatively, a larger
amount and longer duration of TTS sustained during time when
communication is critical for successful mother/calf interactions could
have more serious impacts.
Currently, TTS data only exist for four species of cetaceans
(bottlenose dolphin, beluga whale [Delphinapterus leucas], harbor
porpoise, and Yangtze finless porpoise [Neophocoena asiaeorientalis])
and three species of pinnipeds (northern elephant seal, harbor seal,
and California sea lion) exposed to a limited number of sound sources
(i.e., mostly tones and octave-band noise) in laboratory settings
(e.g., Finneran et al., 2002; Nachtigall et al., 2004; Kastak et al.,
2005; Lucke et al., 2009; Popov et al., 2011). In general, harbor seals
(Kastak et al., 2005; Kastelein et al., 2012a) and harbor porpoises
(Lucke et al., 2009; Kastelein et al., 2012b) have a lower TTS onset
than other measured pinniped or cetacean species. Additionally, the
existing marine mammal TTS data come from a limited number of
individuals within these species. There are no data available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS in
marine mammals or for further discussion of TTS onset thresholds,
please see Southall et al. (2007) and Finneran and Jenkins (2012).
2. Behavioral effects--Behavioral disturbance may include a variety
of effects, including subtle changes in behavior (e.g., minor or brief
avoidance of an area or changes in vocalizations), more conspicuous
changes in similar behavioral activities, and more sustained and/or
potentially severe reactions, such as displacement from or abandonment
of high-quality habitat. Behavioral responses to sound are highly
variable and context-specific and any reactions depend on numerous
intrinsic and extrinsic factors (e.g., species, state of maturity,
experience, current activity, reproductive state, auditory sensitivity,
time of day), as well as the interplay between factors (e.g.,
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007;
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not
only among individuals but also within an individual, depending on
previous experience with a sound source, context, and numerous other
factors (Ellison et al., 2012), and can vary depending on
characteristics associated with the sound source (e.g., whether it is
moving or stationary, number of sources, distance from the source).
Please see Appendices B-C of Southall et al. (2007) for a review of
studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2003). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure. As noted, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (typically seismic airguns or acoustic
harassment devices) have been varied but often consist of avoidance
behavior or other behavioral changes suggesting discomfort (Morton and
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely, and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et
al.; 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may
reflect interruptions in biologically significant activities (e.g.,
foraging) or they may be of little biological significance. The impact
of an alteration to dive behavior resulting from an acoustic exposure
depends on what the animal is doing at the time of the exposure and the
type and magnitude of the response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response.
[[Page 33228]]
Various studies have shown that respiration rates may either be
unaffected or could increase, depending on the species and signal
characteristics, again highlighting the importance in understanding
species differences in the tolerance of underwater noise when
determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et
al., 2007).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007b). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). For example, gray whales
are known to change direction--deflecting from customary migratory
paths--in order to avoid noise from seismic surveys (Malme et al.,
1984). Avoidance may be short-term, with animals returning to the area
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996;
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007).
Longer-term displacement is possible, however, which may lead to
changes in abundance or distribution patterns of the affected species
in the affected region if habituation to the presence of the sound does
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann
et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996). The result of a flight response could range from
brief, temporary exertion and displacement from the area where the
signal provokes flight to, in extreme cases, marine mammal strandings
(Evans and England, 2001). However, it should be noted that response to
a perceived predator does not necessarily invoke flight (Ford and
Reeves, 2008), and whether individuals are solitary or in groups may
influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fish and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Harrington
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However,
Ridgway et al. (2006) reported that increased vigilance in bottlenose
dolphins exposed to sound over a five-day period did not cause any
sleep deprivation or stress effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than one day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive behavioral reactions and multi-day anthropogenic
activities. For example, just because an activity lasts for multiple
days does not necessarily mean that individual animals are either
exposed to activity-related stressors for multiple days or, further,
exposed in a manner resulting in sustained multi-day substantive
behavioral responses.
3. Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Seyle, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments and for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a).
[[Page 33229]]
For example, Rolland et al. (2012) found that noise reduction from
reduced ship traffic in the Bay of Fundy was associated with decreased
stress in North Atlantic right whales. These and other studies lead to
a reasonable expectation that some marine mammals will experience
physiological stress responses upon exposure to acoustic stressors and
that it is possible that some of these would be classified as
``distress.'' In addition, any animal experiencing TTS would likely
also experience stress responses (NRC, 2003).
4. Auditory masking--Sound can disrupt behavior through masking, or
interfering with, an animal's ability to detect, recognize, or
discriminate between acoustic signals of interest (e.g., those used for
intraspecific communication and social interactions, prey detection,
predator avoidance, navigation) (Richardson et al., 1995). Masking
occurs when the receipt of a sound is interfered with by another
coincident sound at similar frequencies and at similar or higher
intensity, and may occur whether the sound is natural (e.g., snapping
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping,
sonar, seismic exploration) in origin. The ability of a noise source to
mask biologically important sounds depends on the characteristics of
both the noise source and the signal of interest (e.g., signal-to-noise
ratio, temporal variability, direction), in relation to each other and
to an animal's hearing abilities (e.g., sensitivity, frequency range,
critical ratios, frequency discrimination, directional discrimination,
age or TTS hearing loss), and existing ambient noise and propagation
conditions.
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is man-made, it may be considered harassment
when disrupting or altering critical behaviors. It is important to
distinguish TTS and PTS, which persist after the sound exposure, from
masking, which occurs during the sound exposure. Because masking
(without resulting in TS) is not associated with abnormal physiological
function, it is not considered a physiological effect, but rather a
potential behavioral effect.
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark, 2009; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Houser and Moore, 2014). Masking can be tested
directly in captive species (e.g., Erbe, 2008), but in wild populations
it must be either modeled or inferred from evidence of masking
compensation. There are few studies addressing real-world masking
sounds likely to be experienced by marine mammals in the wild (e.g.,
Branstetter et al., 2013).
Masking affects both senders and receivers of acoustic signals and
can potentially have long-term chronic effects on marine mammals at the
population level as well as at the individual level. Low-frequency
ambient sound levels have increased by as much as 20 dB (more than
three times in terms of SPL) in the world's ocean from pre-industrial
periods, with most of the increase from distant commercial shipping
(Hildebrand, 2009). All anthropogenic sound sources, but especially
chronic and lower-frequency signals (e.g., from vessel traffic),
contribute to elevated ambient sound levels, thus intensifying masking.
Acoustic Effects, Underwater
Potential Effects of Pile Driving Sound--The effects of sounds from
pile driving might include one or more of the following: temporary or
permanent hearing impairment, non-auditory physical or physiological
effects, behavioral disturbance, and masking (Richardson et al., 1995;
Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007). The
effects of pile driving on marine mammals are dependent on several
factors, including the type and depth of the animal; the pile size and
type, and the intensity and duration of the pile driving sound; the
substrate; the standoff distance between the pile and the animal; and
the sound propagation properties of the environment. Impacts to marine
mammals from pile driving activities are expected to result primarily
from acoustic pathways. As such, the degree of effect is intrinsically
related to the frequency, received level, and duration of the sound
exposure, which are in turn influenced by the distance between the
animal and the source. The further away from the source, the less
intense the exposure should be. The substrate and depth of the habitat
affect the sound propagation properties of the environment. In
addition, substrates that are soft (e.g., sand) would absorb or
attenuate the sound more readily than hard substrates (e.g., rock)
which may reflect the acoustic wave. Soft porous substrates would also
likely require less time to drive the pile, and possibly less forceful
equipment, which would ultimately decrease the intensity of the
acoustic source.
In the absence of mitigation, impacts to marine species could be
expected to include physiological and behavioral responses to the
acoustic signature (Viada et al., 2008). Potential effects from
impulsive sound sources like pile driving can range in severity from
effects such as behavioral disturbance to temporary or permanent
hearing impairment (Yelverton et al., 1973).
Hearing Impairment and Other Physical Effects--Marine mammals
exposed to high intensity sound repeatedly or for prolonged periods can
experience hearing threshold shifts. PTS constitutes injury, but TTS
does not (Southall et al., 2007). Based on the best scientific
information available, the SPLs for the construction activities in this
project are far below the thresholds that could cause TTS or the onset
of PTS: 180 dB re 1 [mu]Pa rms for odontocetes and 190 dB re 1 [mu]Pa
rms for pinnipeds (Table 4).
Non-auditory Physiological Effects--Non-auditory physiological
effects or injuries that theoretically might occur in marine mammals
exposed to strong underwater sound include stress, neurological
effects, bubble formation, resonance effects, and other types of organ
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies
examining such effects are limited. In general, little is known about
the potential for pile driving to cause auditory impairment or other
physical effects in marine mammals. Available data suggest that such
effects, if they occur at all, would presumably be limited to short
distances from the sound source and to activities that extend over a
prolonged period. The available data do not allow identification of a
specific exposure level above which non-auditory effects can be
expected (Southall et al., 2007) or any meaningful quantitative
predictions of the numbers (if any) of
[[Page 33230]]
marine mammals that might be affected in those ways. Marine mammals
that show behavioral avoidance of pile driving, including some
odontocetes and some pinnipeds, are especially unlikely to incur
auditory impairment or non-auditory physical effects.
Disturbance Reactions
Responses to continuous sound, such as vibratory pile installation,
have not been documented as well as responses to pulsed sounds. With
both types of pile driving, it is likely that the onset of pile driving
could result in temporary, short term changes in an animal's typical
behavior and/or avoidance of the affected area. These behavioral
changes may include (Richardson et al., 1995): 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 sound sources are located; and/
or flight responses (e.g., pinnipeds flushing into water from haul-outs
or rookeries). Pinnipeds may increase their haul-out time, possibly to
avoid in-water disturbance (Thorson and Reyff, 2006). If a marine
mammal responds to a stimulus by changing its behavior (e.g., through
relatively minor changes in locomotion direction/speed or vocalization
behavior), the response may or may not constitute taking at the
individual level, and is unlikely to affect the stock or the species as
a whole. However, if a sound source displaces marine mammals from an
important feeding or breeding area for a prolonged period, impacts on
animals, and if so potentially on the stock or species, could
potentially be significant (e.g., Lusseau and Bejder, 2007; Weilgart,
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, or reproduction. Significant
behavioral modifications that could potentially lead to effects on
growth, survival, or reproduction include:
Drastic changes in diving/surfacing patterns (such as
those thought to cause beaked whale stranding due to exposure to
military mid-frequency tactical sonar);
Longer-term habitat abandonment due to loss of desirable
acoustic environment; and
Longer-term cessation of feeding or social interaction.
The onset of behavioral disturbance from anthropogenic sound
depends on both external factors (characteristics of sound sources and
their paths) and the specific characteristics of the receiving animals
(hearing, motivation, experience, demography) and is difficult to
predict (Southall et al., 2007).
Auditory Masking
Natural and artificial sounds can disrupt behavior by masking. The
frequency range of the potentially masking sound is important in
determining any potential behavioral impacts. Because sound generated
from in-water pile driving is mostly concentrated at low frequency
ranges, it may have less effect on high frequency echolocation sounds
made by porpoises. The most intense underwater sounds in the proposed
action are those produced by impact pile driving. Given that the energy
distribution of pile driving covers a broad frequency spectrum, sound
from these sources would likely be within the audible range of marine
mammals present in the project area. Impact pile driving activity is
relatively short-term, with rapid pulses occurring for approximately
fifteen minutes per pile. The probability for impact pile driving
resulting from this proposed action masking acoustic signals important
to the behavior and survival of marine mammal species is low. Vibratory
pile driving is also relatively short-term, with rapid oscillations
occurring for approximately one and a half hours per pile. It is
possible that vibratory pile driving resulting from this proposed
action may mask acoustic signals important to the behavior and survival
of marine mammal species, but the short-term duration and limited
affected area would result in insignificant impacts from masking. Any
masking event that could possibly rise to Level B harassment under the
MMPA would occur concurrently within the zones of behavioral harassment
already estimated for vibratory and impact pile driving, and which have
already been taken into account in the exposure analysis.
Acoustic Effects, Airborne--Pinnipeds that occur near the project
site could be exposed to airborne sounds associated with pile driving
that have the potential to cause behavioral harassment, depending on
their distance from pile driving activities. Cetaceans are not expected
to be exposed to airborne sounds that would result in harassment as
defined under the MMPA.
Airborne noise will primarily be an issue for pinnipeds that are
swimming or hauled out near the project site within the range of noise
levels elevated above the acoustic criteria in Table 4. We recognize
that pinnipeds in the water could be exposed to airborne sound that may
result in behavioral harassment when looking with heads above water.
Most likely, airborne sound would cause behavioral responses similar to
those discussed above in relation to underwater sound. For instance,
anthropogenic sound could cause hauled-out pinnipeds to exhibit changes
in their normal behavior, such as reduction in vocalizations, or cause
them to temporarily abandon the area and move further from the source.
However, these animals would previously have been `taken' as a result
of exposure to underwater sound above the behavioral harassment
thresholds, which are in all cases larger than those associated with
airborne sound. Thus, the behavioral harassment of these animals is
already accounted for in these estimates of potential take. Multiple
instances of exposure to sound above NMFS' thresholds for behavioral
harassment are not believed to result in increased behavioral
disturbance, in either nature or intensity of disturbance reaction.
Therefore, we do not believe that authorization of incidental take
resulting from airborne sound for pinnipeds is warranted, and airborne
sound is not discussed further here.
Anticipated Effects on Habitat
The proposed activities at the Ferry Terminal would not result in
permanent negative impacts to habitats used directly by marine mammals,
but may have potential short-term impacts to food sources such as
forage fish and may affect acoustic habitat (see masking discussion
above). There are no known foraging hotspots or other ocean bottom
structure of significant biological importance to marine mammals
present in the marine waters of the project area. Therefore, the main
impact issue associated with the proposed activity would be temporarily
elevated sound levels and the associated direct effects on marine
mammals, as discussed previously in this document. The primary
potential acoustic impacts to marine mammal habitat are associated with
elevated sound levels produced by vibratory and impact pile driving and
removal in the area. However, other potential impacts to the
surrounding habitat from physical disturbance are also possible.
[[Page 33231]]
Pile Driving Effects on Potential Prey (Fish)
Construction activities would produce continuous (i.e., vibratory
pile driving sounds and pulsed (i.e. impact driving) sounds. Fish react
to sounds that are especially strong and/or intermittent low-frequency
sounds. Short duration, sharp sounds can cause overt or subtle changes
in fish behavior and local distribution. Hastings and Popper (2005)
identified several studies that suggest fish may relocate to avoid
certain areas of sound energy. Additional studies have documented
effects of pile driving on fish, although several are based on studies
in support of large, multiyear bridge construction projects (e.g.,
Scholik and Yan, 2001, 2002; Popper and Hastings, 2009). Sound pulses
at received levels of 160 dB may cause subtle changes in fish behavior.
SPLs of 180 dB may cause noticeable changes in behavior (Pearson et
al., 1992; Skalski et al., 1992). SPLs of sufficient strength have been
known to cause injury to fish and fish mortality.
The most likely impact to fish from pile driving activities at the
project area would be temporary behavioral avoidance of the area. The
duration of fish avoidance of this area after pile driving stops is
unknown, but a rapid return to normal recruitment, distribution and
behavior is anticipated. In general, impacts to marine mammal prey
species are expected to be minor and temporary due to the short
timeframe for the project.
Pile Driving Effects on Potential Foraging Habitat
The area likely impacted by the project is relatively small
compared to the available habitat in San Francisco Bay. Avoidance by
potential prey (i.e., fish) of the immediate area due to the temporary
loss of this foraging habitat is also possible. The duration of fish
avoidance of this area after pile driving stops is unknown, but a rapid
return to normal recruitment, distribution and behavior is anticipated.
Any behavioral avoidance by fish of the disturbed area would still
leave significantly large areas of fish and marine mammal foraging
habitat in the San Francisco ferry terminal and nearby vicinity.
In summary, given the short daily duration of sound associated with
individual pile driving events and the relatively small areas being
affected, pile driving activities associated with the proposed action
are not likely to have a permanent, adverse effect on any fish habitat,
or populations of fish species. Thus, any impacts to marine mammal
habitat are not expected to cause significant or long-term consequences
for individual marine mammals or their populations.
Proposed Mitigation
In order to issue an IHA 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 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.
Measurements from similar pile driving events were coupled with
practical spreading loss to estimate zones of influence (ZOI; see
Estimated Take by Incidental Harassment); these values were used to
develop mitigation measures for pile driving activities at the ferry
terminal. The ZOIs effectively represent the mitigation zone that would
be established around each pile to prevent Level A harassment to marine
mammals, while providing estimates of the areas within which Level B
harassment might occur. In addition to the specific measures described
later in this section, WETA would conduct briefings between
construction supervisors and crews, marine mammal monitoring team, and
WETA staff prior to the start of all pile driving activity, and when
new personnel join the work, in order to explain responsibilities,
communication procedures, marine mammal monitoring protocol, and
operational procedures.
Monitoring and Shutdown for Pile Driving
The following measures would apply to WETA's mitigation through
shutdown and disturbance zones:
Shutdown Zone--For all pile driving activities, WETA will establish
a shutdown zone intended to contain the area in which SPLs equal or
exceed the 180/190 dB rms acoustic injury criteria for cetaceans and
pinnipeds, respectively. The purpose of a shutdown zone is to define an
area within which shutdown of activity would occur upon sighting of a
marine mammal (or in anticipation of an animal entering the defined
area), thus preventing injury of marine mammals (as described
previously under Potential Effects of the Specified Activity on Marine
Mammals, serious injury or death are unlikely outcomes even in the
absence of mitigation measures). Modeled radial distances for shutdown
zones are shown in Table 6. However, a minimum shutdown zone of 10 m
will be established during all pile driving activities, regardless of
the estimated zone. Vibratory pile driving activities are not predicted
to produce sound exceeding the 180/190-dB Level A harassment threshold,
but these precautionary measures are intended to prevent the already
unlikely possibility of physical interaction with construction
equipment and to further reduce any possibility of acoustic injury.
Disturbance Zone--Disturbance zones are the areas in which SPLs
equal or exceed 160 and 120 dB rms (for impulse and continuous sound,
respectively). Disturbance zones provide utility for monitoring
conducted for mitigation purposes (i.e., shutdown zone monitoring) by
establishing monitoring protocols for areas adjacent to the shutdown
zones. Monitoring of disturbance zones enables observers to be aware of
and communicate the presence of marine mammals in the project area but
outside the shutdown zone and thus prepare for potential shutdowns of
activity. However, the primary purpose of disturbance zone monitoring
is for documenting instances of Level B harassment; disturbance zone
monitoring is discussed in greater detail later (see Proposed
Monitoring and Reporting). Nominal radial distances for disturbance
zones are shown in Table 6. Given the size of the disturbance zone for
vibratory pile driving, it is impossible to guarantee that all animals
would be observed or to make comprehensive observations of fine-scale
behavioral reactions to sound, and only a portion of the zone (e.g.,
what may be reasonably observed by visual observers stationed within
the turning basin) would be observed.
In order to document observed instances of harassment, monitors
record all marine mammal observations, regardless of location. The
observer's location, as well as the location of the pile being driven,
is known from a GPS. The location of the animal is estimated as a
distance from the observer, which is then compared to the location from
the pile. It may then be estimated whether the animal was exposed to
sound levels constituting incidental harassment on the basis of
predicted distances to relevant thresholds in post-processing of
observational and acoustic data, and a precise accounting of observed
incidences of harassment created. This information may then be used to
extrapolate observed takes to reach an approximate understanding of
actual total takes.
Monitoring Protocols--Monitoring would be conducted before, during,
and after pile driving activities. In addition, observers shall record
all instances of
[[Page 33232]]
marine mammal occurrence, regardless of distance from activity, and
shall document any behavioral reactions in concert with distance from
piles being driven. Observations made outside the shutdown zone will
not result in shutdown; that pile segment would be completed without
cessation, unless the animal approaches or enters the shutdown zone, at
which point all pile driving activities would be halted. Monitoring
will take place from fifteen minutes prior to initiation through thirty
minutes post-completion of pile driving activities. Pile driving
activities include the time to install or remove a single pile or
series of piles, as long as the time elapsed between uses of the pile
driving equipment is no more than thirty minutes. Please see the
Monitoring Plan (www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), developed by WETA in agreement with NMFS, for full
details of the monitoring protocols.
The following additional measures apply to visual monitoring:
(1) Monitoring will be conducted by qualified observers, who will
be placed at the best vantage point(s) practicable to monitor for
marine mammals and implement shutdown/delay procedures when applicable
by calling for the shutdown to the hammer operator. Qualified observers
are typically trained biologists, with the following minimum
qualifications:
Visual acuity in both eyes (correction is permissible)
sufficient for discernment of moving targets at the water's surface
with ability to estimate target size and distance; use of binoculars
may be necessary to correctly identify the target;
Experience and ability to conduct field observations and
collect data according to assigned protocols (this may include academic
experience);
Experience or training in the field identification of
marine mammals, including the identification of behaviors;
Sufficient training, orientation, or experience with the
construction operation to provide for personal safety during
observations;
Writing skills sufficient to prepare a report of
observations including but not limited to the number and species of
marine mammals observed; dates and times when in-water construction
activities were conducted; dates and times when in-water construction
activities were suspended to avoid potential incidental injury from
construction sound of marine mammals observed within a defined shutdown
zone; and marine mammal behavior; and
Ability to communicate orally, by radio or in person, with
project personnel to provide real-time information on marine mammals
observed in the area as necessary.
(2) Prior to the start of pile driving activity, the shutdown zone
will be monitored for fifteen minutes to ensure that it is clear of
marine mammals. Pile driving will only commence once observers have
declared the shutdown zone clear of marine mammals; animals will be
allowed to remain in the shutdown zone (i.e., must leave of their own
volition) and their behavior will be monitored and documented. The
shutdown zone may only be declared clear, and pile driving started,
when the entire shutdown zone is visible (i.e., when not obscured by
dark, rain, fog, etc.). In addition, if such conditions should arise
during impact pile driving that is already underway, the activity would
be halted.
(3) If a marine mammal approaches or enters the shutdown zone
during the course of pile driving operations, activity will be halted
and delayed until either the animal has voluntarily left and been
visually confirmed beyond the shutdown zone or fifteen minutes have
passed without re-detection of the animal. Monitoring will be conducted
throughout the time required to drive a pile.
(4) Using delay and shut-down procedures, if a species for which
authorization has not been granted (including but not limited to
Guadalupe fur seals and humpback whales) or if a species for which
authorization has been granted but the authorized takes are met,
approaches or is observed within the Level B harassment zone,
activities will shut down immediately and not restart until the animals
have been confirmed to have left the area.
Soft Start
The use of a soft start procedure is believed to provide additional
protection to marine mammals by warning or providing a chance to leave
the area prior to the hammer operating at full capacity, and typically
involves a requirement to initiate sound from the hammer at reduced
energy followed by a waiting period. This procedure is repeated two
additional times. It is difficult to specify the reduction in energy
for any given hammer because of variation across drivers and, for
impact hammers, the actual number of strikes at reduced energy will
vary because operating the hammer at less than full power results in
``bouncing'' of the hammer as it strikes the pile, resulting in
multiple ``strikes.'' For impact driving, we require an initial set of
three strikes from the impact hammer at reduced energy, followed by a
thirty-second waiting period, then two subsequent three strike sets.
Soft start will be required at the beginning of each day's impact pile
driving work and at any time following a cessation of impact pile
driving of thirty minutes or longer.
We have carefully evaluated WETA's proposed mitigation measures and
considered their effectiveness in past implementation to preliminarily
determine whether they are likely to effect the least practicable
impact on the affected marine mammal species and stocks and their
habitat. Our evaluation of potential measures included consideration of
the following factors in relation to one another: (1) The manner in
which, and the degree to which, the successful implementation of the
measure is expected to minimize adverse impacts to marine mammals, (2)
the proven or likely efficacy of the specific measure to minimize
adverse impacts as planned; and (3) the practicability of the measure
for applicant implementation.
Any mitigation measure(s) we prescribe should be able to
accomplish, have a reasonable likelihood of accomplishing (based on
current science), or contribute to the accomplishment of one or more of
the general goals listed below:
(1) Avoidance or minimization of injury or death of marine mammals
wherever possible (goals 2, 3, and 4 may contribute to this goal).
(2) A reduction in the number (total number or number at
biologically important time or location) of individual marine mammals
exposed to stimuli expected to result in incidental take (this goal may
contribute to 1, above, or to reducing takes by behavioral harassment
only).
(3) A reduction in the number (total number or number at
biologically important time or location) of times any individual marine
mammal would be exposed to stimuli expected to result in incidental
take (this goal may contribute to 1, above, or to reducing takes by
behavioral harassment only).
(4) A reduction in the intensity of exposure to stimuli expected to
result in incidental take (this goal may contribute to 1, above, or to
reducing the severity of behavioral harassment only).
(5) Avoidance or minimization of adverse effects to marine mammal
habitat, paying particular attention to the prey base, blockage or
limitation of passage to or from biologically important areas,
permanent destruction of habitat, or temporary disturbance of habitat
during a biologically important time.
[[Page 33233]]
(6) For monitoring directly related to mitigation, an increase in
the probability of detecting marine mammals, thus allowing for more
effective implementation of the mitigation.
Based on our evaluation of WETA's proposed measures, as well as any
other potential measures that may be relevant to the specified
activity, we have preliminarily determined that the proposed mitigation
measures provide the means of effecting the least practicable impact on
marine mammal species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, and areas of similar
significance.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth ``requirements pertaining to
the monitoring and reporting of such taking.'' The MMPA implementing
regulations at 50 CFR 216.104 (a)(13) indicate that requests for
incidental take authorizations 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.
Any monitoring requirement we prescribe should improve our
understanding of one or more of the following:
Occurrence of marine mammal species in action area (e.g.,
presence, abundance, distribution, density).
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) Action or environment
(e.g., source characterization, propagation, ambient noise); (2)
Affected species (e.g., life history, dive patterns); (3) Co-occurrence
of marine mammal species with the action; or (4) Biological or
behavioral context of exposure (e.g., age, calving or feeding areas).
Individual responses to acute stressors, or impacts of
chronic exposures (behavioral or physiological).
How anticipated responses to stressors impact either: (1)
Long-term fitness and survival of an individual; or (2) Population,
species, or stock.
Effects on marine mammal habitat and resultant impacts to
marine mammals.
Mitigation and monitoring effectiveness.
WETA's proposed monitoring and reporting is also described in their
Marine Mammal Monitoring Plan, on the Internet at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm.
Visual Marine Mammal Observations
WETA will collect sighting data and behavioral responses to
construction for marine mammal species observed in the region of
activity during the period of activity. All observers (MMOs) will be
trained in marine mammal identification and behaviors and are required
to have no other construction-related tasks while conducting
monitoring. WETA will monitor the shutdown zone and disturbance zone
before, during, and after pile driving, with observers located at the
best practicable vantage points. Based on our requirements, WETA would
implement the following procedures for pile driving:
MMOs would be located at the best vantage point(s) in
order to properly see the entire shutdown zone and as much of the
disturbance zone as possible.
During all observation periods, observers will use
binoculars and the naked eye to search continuously for marine mammals.
If the shutdown zones are obscured by fog or poor lighting
conditions, pile driving at that location will not be initiated until
that zone is visible. Should such conditions arise while impact driving
is underway, the activity would be halted.
The shutdown and disturbance zones around the pile will be
monitored for the presence of marine mammals before, during, and after
any pile driving or removal activity.
Individuals implementing the monitoring protocol will assess its
effectiveness using an adaptive approach. The monitoring biologists
will use their best professional judgment throughout implementation and
seek improvements to these methods when deemed appropriate. Any
modifications to protocol will be coordinated between NMFS and WETA.
Data Collection
We require that observers use approved data forms. Among other
pieces of information, WETA will record detailed information about any
implementation of shutdowns, including the distance of animals to the
pile and description of specific actions that ensued and resulting
behavior of the animal, if any. In addition, WETA will attempt to
distinguish between the number of individual animals taken and the
number of incidences of take. We require that, at a minimum, the
following information be collected on the sighting forms:
Date and time that monitored activity begins or ends;
Construction activities occurring during each observation
period;
Weather parameters (e.g., percent cover, visibility);
Water conditions (e.g., sea state, tide state);
Species, numbers, and, if possible, sex and age class of
marine mammals;
Description of any observable marine mammal behavior
patterns, including bearing and direction of travel, and if possible,
the correlation to SPLs;
Distance from pile driving activities to marine mammals
and distance from the marine mammals to the observation point;
Description of implementation of mitigation measures
(e.g., shutdown or delay);
Locations of all marine mammal observations; and
Other human activity in the area.
Reporting
A draft report would be submitted to NMFS within 90 days of the
completion of marine mammal monitoring, or sixty days prior to the
requested date of issuance of any future IHA for projects at the same
location, whichever comes first. The report will include marine mammal
observations pre-activity, during-activity, and post-activity during
pile driving days, and will also provide descriptions of any behavioral
responses to construction activities by marine mammals and a complete
description of all mitigation shutdowns and the results of those
actions and an extrapolated total take estimate based on the number of
marine mammals observed during the course of construction. A final
report must be submitted within thirty days following resolution of
comments on the draft report.
Estimated Take by Incidental Harassment
Except with respect to certain activities not pertinent here,
section 3(18) of 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].''
All anticipated takes would be by Level B harassment resulting from
[[Page 33234]]
vibratory and impact pile driving and involving temporary changes in
behavior. The proposed mitigation and monitoring measures are expected
to minimize the possibility of injurious or lethal takes such that take
by Level A harassment, serious injury, or mortality is considered
discountable. However, it is unlikely that injurious or lethal takes
would occur even in the absence of the planned mitigation and
monitoring measures.
Given the many uncertainties in predicting the quantity and types
of impacts of sound on marine mammals, it is common practice to
estimate how many animals are likely to be present within a particular
distance of a given activity, or exposed to a particular level of
sound. In practice, depending on the amount of information available to
characterize daily and seasonal movement and distribution of affected
marine mammals, it can be difficult to distinguish between the number
of individuals harassed and the instances of harassment and, when
duration of the activity is considered, it can result in a take
estimate that overestimates the number of individuals harassed. In
particular, for stationary activities, it is more likely that some
smaller number of individuals may accrue a number of incidences of
harassment per individual than for each incidence to accrue to a new
individual, especially if those individuals display some degree of
residency or site fidelity and the impetus to use the site (e.g.,
because of foraging opportunities) is stronger than the deterrence
presented by the harassing activity.
The area where the ferry terminal is located is not considered
important habitat for marine mammals, as it is a highly industrial area
with high levels of vessel traffic and background noise. While there
are harbor seal haul outs within two miles of the construction activity
at Yerba Buena Island, and a California sea lion haul out approximately
1.5 miles away at pier 39, behavioral disturbances that could result
from anthropogenic sound associated with these activities are expected
to affect only a relatively small number of individual marine mammals
that may venture near the ferry terminal, although those effects could
be recurring over the life of the project if the same individuals
remain in the project vicinity. WETA has requested authorization for
the incidental taking of small numbers of harbor seals, Northern
elephant seals, Norther fur seals, California sea lions, harbor
porpoise, bottlenose dolphin, and gray whales near the San Francisco
Ferry Terminal that may result from pile driving during construction
activities associated with the project described previously in this
document.
In order to estimate the potential instances of take that may occur
incidental to the specified activity, we must first estimate the extent
of the sound field that may be produced by the activity and then
consider in combination with information about marine mammal density or
abundance in the project area. We first provide information on
applicable sound thresholds for determining effects to marine mammals
before describing the information used in estimating the sound fields,
the available marine mammal density or abundance information, and the
method of estimating potential instances of take.
Sound Thresholds
We use generic sound exposure thresholds to determine when an
activity that produces sound might result in impacts to a marine mammal
such that a take by harassment might occur. These thresholds (Table 4)
are used to estimate when harassment may occur (i.e., when an animal is
exposed to levels equal to or exceeding the relevant criterion) in
specific contexts; however, useful contextual information that may
inform our assessment of effects is typically lacking and we consider
these thresholds as step functions. NMFS is working to revise these
acoustic guidelines; for more information on that process, please visit
www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.
Table 4--Current Acoustic Exposure Criteria
------------------------------------------------------------------------
Criterion Definition Threshold
------------------------------------------------------------------------
Level A harassment Injury (PTS--any 180 dB (cetaceans)/
(underwater). level above that 190 dB (pinnipeds)
which is known (rms).
to cause TTS).
Level B harassment Behavioral 160 dB (impulsive
(underwater). disruption. source)/120 dB
(continuous source)
(rms).
Level B harassment (airborne). Behavioral 90 dB (harbor seals)/
disruption. 100 dB (other
pinnipeds)
(unweighted).
------------------------------------------------------------------------
Distance to Sound Thresholds
Underwater Sound Propagation Formula--Pile driving generates
underwater noise that can potentially result in disturbance to marine
mammals in the project area. Transmission loss (TL) is the decrease in
acoustic intensity as an acoustic pressure wave propagates out from a
source. TL parameters vary with frequency, temperature, sea conditions,
current, source and receiver depth, water depth, water chemistry, and
bottom composition and topography. The general formula for underwater
TL is:
TL = B * log10(R1/R2), where
R1 = the distance of the modeled SPL from the driven
pile, and
R2 = the distance from the driven pile of the initial
measurement.
This formula neglects loss due to scattering and absorption, which is
assumed to be zero here. The degree to which underwater sound
propagates away from a sound source is dependent on a variety of
factors, most notably the water bathymetry and presence or absence of
reflective or absorptive conditions including in-water structures and
sediments. Spherical spreading occurs in a perfectly unobstructed
(free-field) environment not limited by depth or water surface,
resulting in a 6 dB reduction in sound level for each doubling of
distance from the source (20*log[range]). Cylindrical spreading occurs
in an environment in which sound propagation is bounded by the water
surface and sea bottom, resulting in a reduction of 3 dB in sound level
for each doubling of distance from the source (10*log[range]). A
practical spreading value of 15 is often used under conditions, such as
at the San Francisco Ferry Terminal, where water increases with depth
as the receiver moves away from the shoreline, resulting in an expected
propagation environment that would lie between spherical and
cylindrical spreading loss conditions. Practical spreading loss (4.5 dB
reduction in sound level for each doubling of distance) is assumed
here.
Underwater Sound--The intensity of pile driving sounds is greatly
influenced by factors such as the type of piles, hammers, and the
physical environment in which the activity takes place. A number of
studies, primarily on the west coast, have measured sound produced
during underwater pile driving projects. However, these data
[[Page 33235]]
are largely for impact driving of steel pipe piles and concrete piles
as well as vibratory driving of steel pipe piles.
In order to determine reasonable SPLs and their associated effects
on marine mammals that are likely to result from vibratory or impact
pile driving at the ferry terminal, we considered existing measurements
from similar physical environments (e.g. estuarine areas of soft
substrate where water depths are less than 16 feet).
For 24- and 36-inch steel piles, projects include the driving of
similarly sized piles at the Alameda Bay Ship and Yacht project; the
Rodeo Dock Repair project; and the Amorco Wharf Repair project (Table
5). During impact pile-driving associated with these projects, measured
sound levels averaged about 193 dB rms at 10m for 36-inch piles, and
190 dB rms at 10m for 24-inch piles (Caltrans, 2012). Bubble curtains
will be used during the installation of these piles, which is expected
to reduce noise levels by about 10 dB rms (Caltrans, 2015a). Impact
driving of these piles would produce noise levels above the Level A 190
dB threshold for pinnipeds over a distance of 11 feet (4 meters) for
36-inch piles and over a distance of 7 feet (2 meters) for 24-inch
piles assuming practical spreading. Impact driving of steel piles would
exceed the Level A 180 dB threshold for cetaceans over a distance of 52
feet (16 meters) for 36-inch piles, and 33 feet (or 10 meters) for 24-
inch piles. It is estimated that an average of four of these piles
would be installed per day.
Projects conducted under similar circumstances with similar piles
were reviewed to approximate the noise effects of the 14-inch wood
piles. The best match for estimated noise levels is from the impact
driving of timber piles at the Port of Benicia (Table 5). Noise levels
produced during this installation were an average of 170 dB peak, and
158 dB rms at 33 feet (10 meters) from the pile (Caltrans, 2015a). It
is estimated that an average of four of these piles would be installed
per day. Based on the above sound levels, installation of the 14-inch
plastic-coated wood piles would not produce rms values above the Level
A or Level B thresholds.
The best fit data for 24-inch-diameter steel shell piles comes from
projects completed in Shasta County, California, and the Stockton
Marina, Stockton, California (Table 5). For these projects, the typical
noise levels for pile-driving events were 175 dB peak, and 163 dB rms
at 33 feet (10 meters) (Caltrans, 2012).
A review of available acoustic data for pile driving indicates that
Test Pile Program at Naval Base Kitsap at Bangor, Washington
(Illingsworth and Rodkin, 2013) provides the best match data for
vibratory installation of 36-inch piles (Table 5). For 36-inch-diameter
piles driven by the Navy, the average level for all pile-driving events
was 159 dB rms at 33 feet (10 meters). There was a considerable range
in the rms levels measured across a pile-driving event; with measured
values from 147 to 169 dB rms, the higher value is used in this
analysis. It is estimated that an average of four of these piles would
be extracted per day of pile driving during the proposed project. Based
on the above sound levels, vibratory installation of the 24- and 36-
inch steel pipe piles would produce rms values above the Level A and
Level B thresholds (Table 6).
It is estimated that an average of four 14-inch polyurethane-coated
wood piles would be installed per day of pile driving. The best match
for estimated noise levels for vibratory driving of these piles is from
the Hable River in Hampshire, England, where wooden piles were
installed with this method (Table 5). Rms noise levels produced during
this installation were on average 142 dB rms at 33 feet (10 meters)
from the pile (Nedwell et al., 2005). Based on these measure levels,
vibratory installation of the 14-inch polyurethane- coated wood-fender
piles would not produce noise levels above the Level A 190 or 180 dB
rms thresholds; however, the 120 dB RMS Level B threshold would be
exceeded over a radius of 293 meters assuming practical spreading.
Approximately 350 wood and concrete piles, 12 to 18 inches in
diameter, would be removed using a vibratory pile-driver. With the
vibratory hammer activated, an upward force would be applied to the
pile to remove it from the sediment. On average, 12 of these piles
would be extracted per work day. Extraction time needed for each pile
may vary greatly, but could require approximately 400 seconds
(approximately 7 minutes) from an APE 400B King Kong or similar driver.
The most applicable noise values for wooden pile removal from which to
base estimates for the terminal expansion project are derived from
measurements taken at the Port Townsend dolphin pile removal in the
State of Washington (Table 5). During vibratory pile extraction
associated with this project, measured peak noise levels were
approximately 164 dB at 16 m, and the rms was approximately 150 dB
(WSDOT, 2011). Applicable sound values for the removal of concrete
piles could not be located, but they are expected to be similar to the
levels produced by wooden piles described above, because they are
similarly sized, nonmetallic, and will be removed using the same
methods. Based on the above noise levels, vibratory extraction of the
timber and concrete piles would not produce noise levels above the
Level A 190 dB or 180 dB thresholds. The radius over which the Level B
120 dB rms threshold could be exceeded is approximately 1,920 feet (585
meters) assuming practical spreading.
Table 5--Underwater SPLs From Monitored Construction Activities Using Vibratory and Impact Hammers
----------------------------------------------------------------------------------------------------------------
Project and location Pile size and type Hammer type/method Water depth (m) Measured SPLs
----------------------------------------------------------------------------------------------------------------
the Alameda Bay Ship and Yacht 40-in Steel pipe.. Impact driving.... 13................ 195 RMS at 10 m.
project \1\.
the Rodeo Dock Repair project 24- in steel pile. Impact driving.... 5................. 189 RMS at 10 m.
\1\.
the Amorco Wharf Repair project 24- in steel pile. Impact driving.... >12............... 190 RMS at 10 m.
\1\.
Port of Benicia \2\............. Timber pile....... n/a............... 11................ 170 dB RMS at 10
m.
Shasta County, California \1\... 24-inch steel pipe Vibratory driving. >2................ 157, 159 RMS at 10
piles. m.
the Stockton Marina, Stockton, 20-inch- steel Vibratory driving. 3................. 169, 156 RMS at 10
California \1\. shell piles. m.
Test Pile Program at Naval Base 36-inch TTP....... Vibratory driving. n/a............... 159 dB RMS at 10
Kitsap at Bangor, WA \3\. m.
Hable River in Hampshire, 14-inch Vibratory driving. n/a............... 142 dB RMS at 10
England \4\. polyurethane- m.
coated wood piles.
Port Townsend dolphin pile Dolphin pile...... Vibratory 5................. 150 RMS at 16 m.
removal in the State of extraction.
Washington \5\.
----------------------------------------------------------------------------------------------------------------
\1\ Caltrans, 2012
\2\ Caltrans, 2015a
\3\ Illingsworth and Rodkin, 2013
\4\ Nedwell, 2015
\5\ WSDOT, 2011
[[Page 33236]]
All calculated distances to, and the total area encompassed by, the
marine mammal sound thresholds are provided in Table 6. No
physiological responses are expected from pile-driving operations
occurring during project construction. Vibratory pile extraction and
driving does not generate high-peak sound-pressure levels commonly
associated with physiological damage. Impact driving can produce noise
levels in excess of the Level A thresholds, but only within 50 feet (15
meters) of impact-driving of 36-inch piles. The shutdown zone will be
equivalent to the area over which Level A harassment may occur,
including the 180 dB re 1 [mu]Pa (cetaceans) and 190 dB re 1 [mu]Pa
(pinnipeds) isopleths (Table 6); however, a minimum 10 m shutdown zone
will be applied to the these zones as a precautionary measure intended
to prevent the already unlikely possibility of physical interaction
with construction equipment and to further reduce any possibility of
acoustic injury. The disturbance zones will be equivalent to the area
over which Level B harassment may occur, including160 dB re 1 [mu]Pa
(impact pile driving) and 120 dB re 1 [mu]Pa (vibratory pile driving)
isopleths (Table 6).
Table 6--Distances to Relevant Underwater Sound Thresholds and Areas of Ensonification
----------------------------------------------------------------------------------------------------------------
Source levels Distance to threshold (m)
Project element requiring pile at 10 meters ------------------------------------------------ Area for level
installation ---------------- 160/120 dB RMS B threshold
RMS 190 dB RMS \1\ 180 dB RMS \1\ \2\ (km\2\)
----------------------------------------------------------------------------------------------------------------
South Basin Pile Demolition and Removal
----------------------------------------------------------------------------------------------------------------
18-Inch Wood Piles--Vibratory 150 0 < 1 1,000 1.27
Driver.........................
18-Inch Concrete Piles-- 150 0 < 1 1,000 1.27
Vibratory Driver...............
36-Inch Steel Piles--Vibratory 170 < 1 2 18,478 86.52
Driver.........................
----------------------------------------------------------------------------------------------------------------
Embarcadero Plaza and East Bayside Promenade and Gates E, F, and G Dolphin and Guide Piles
----------------------------------------------------------------------------------------------------------------
36-Inch Steel Piles--Vibratory 169 < 1 2 18,478 86.52
Driver.........................
36-Inch Steel Piles--Impact 198 4 16 341 0.18
Driver (BCA)3..................
24-Inch Steel Piles--Vibratory 163 0 1 7,356 38.07
Driver.........................
24-Inch Steel Piles--Impact 193 2 10 215 0.09
Driver (BCA)...................
----------------------------------------------------------------------------------------------------------------
Fender Piles
----------------------------------------------------------------------------------------------------------------
14-Inch Wood Piles--Vibratory 142 0 0 293 0.14
Driver.........................
14-Inch Wood Piles--Impact 158 0 0 7 0
Driver.........................
----------------------------------------------------------------------------------------------------------------
\1\ For underwater noise, the Level A harassment threshold for cetaceans is 180 dB and 190 dB for pinnipeds.
\2\ For underwater noise, the Level B harassment (disturbance) threshold is 160 dB for impulsive noise and
typical ambient levels (120 dB) for continuous noise.
BCA Bubble curtain attenuation will be used during impact driving of steel piles.
dB decibels.
RMS root mean square.
Marine Mammal Densities
At-sea densities for marine mammal species have not be determined
in San Francisco Bay; therefore, estimates here are determined by using
observational data taken during marine mammal monitoring associated
with the Richmond-San Rafael Bridge retrofit project, the San
Francisco-Oakland Bay Bridge (SFOBB), which has been ongoing for the
past 15 years, and anecdotal observational reports from local entities.
It is not currently possible to identify all observed individuals to
stock.
Description of Take Calculation
All estimates are conservative and include the following
assumptions:
All pilings installed at each site would have an
underwater noise disturbance equal to the piling that causes the
greatest noise disturbance (i.e., the piling farthest from shore)
installed with the method that has the largest ZOI. The largest
underwater disturbance ZOI would be produced by vibratory driving steel
piles. The ZOIs for each threshold are not spherical and are truncated
by land masses on either side of the channel which would dissipate
sound pressure waves.
Exposures were based on estimated total of 106 work days.
Each activity ranges in amount of days needed to be completed (Table
1). Note that impact driving is likely to occur only on days when
vibratory driving occurs.
In absence of site specific underwater acoustic
propagation modeling, the practical spreading loss model was used to
determine the ZOI.
All marine mammal individuals potentially available are
assumed to be present within the relevant area, and thus incidentally
taken;
An individual can only be taken once during a 24-h period;
and,
Exposures to sound levels at or above the relevant
thresholds equate to take, as defined by the MMPA.
The estimation of marine mammal takes typically uses the following
calculation:
For harbor seals and California sea lions: Level B exposure
estimate = D (density) * Area of ensonification) * Number of days of
noise generating activities.
For all other marine mammal species: Level B exposure estimate = N
(number of animals) in the area * Number of days of noise generating
activities.
To account for the increase in California sea lion density due to
El Ni[ntilde]o, the daily take estimated from the observed density has
been increased by a factor of 10 for each day that pile driving occurs.
There are a number of reasons why estimates of potential instances
of take may be overestimates of the number of individuals taken,
assuming that available density or abundance estimates and estimated
ZOI areas are accurate. We assume, in the absence of information
supporting a more refined conclusion, that the output of the
calculation represents the number of individuals that may be taken by
the specified activity. In fact, in the context of stationary
activities such as pile driving and in areas where resident animals may
be present, this number
[[Page 33237]]
represents the number of instances of take that may accrue to a smaller
number of individuals, with some number of animals being exposed more
than once per individual. While pile driving can occur any day
throughout the in-water work window, and the analysis is conducted on a
per day basis, only a fraction of that time (typically a matter of
hours on any given day) is actually spent pile driving. The potential
effectiveness of mitigation measures in reducing the number of takes is
typically not quantified in the take estimation process. For these
reasons, these take estimates may be conservative, especially if each
take is considered a separate individual animal, and especially for
pinnipeds.
The quantitative exercise described above indicates that no
instances of Level A harassment would be expected, independent of the
implementation of required mitigation measures. See Table 7 for total
estimated instances of take.
Table 7--Calculations for Incidental Take Estimation
--------------------------------------------------------------------------------------------------------------------------------------------------------
Estimated take by level B harassment (take per day/total)
Number of -----------------------------------------------------------------------------------
Pile type Pile-driver type driving Northern Harbor Northern Bottlenose
days Harbor CA Sea elephant porpoise Gray Whale fur seal dolphin
seal lion \1\ seal \2\ \2\ \2\ \2\ \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
2016 Work Season
--------------------------------------------------------------------------------------------------------------------------------------------------------
Wood/concrete pile removal....... Vibratory............ 30 1/30 10/300 NA NA NA NA NA
36-inch dolphin pile removal..... Vibratory............ 1 27/26 110/110 NA NA NA NA NA
Embarcadero Plaza................ Vibratory \3\........ 65 26/1,690 110/7,150 NA NA NA NA NA
36-inch steel piles OR...........
24-inch steel piles.............. Vibratory \3\........ 65 12/780 50/3,250 NA NA NA NA NA
14-inch wood pile................ Vibratory \3\........ 10 1/10 10/100 NA NA NA NA NA
----------------------------------------------------------------------------------------------------------------------
Project Total (2016) \3\..... ..................... 106 1,756 7,660 14 6 2 10 30
--------------------------------------------------------------------------------------------------------------------------------------------------------
2017 Work Season
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gate F and G Guide Piles (36-inch Vibratory \3\........ 12 1/12 4/48 NA NA NA NA NA
steel).
Gate E Guide Pile Removal (36- Vibratory............ 6 1/6 4/24 NA NA NA NA NA
inch steel).
Gate E Guide Pile Installation Vibratory \3\........ 6 1/6 4/24 NA NA NA NA NA
(36-inch steel).
----------------------------------------------------------------------------------------------------------------------
Project Total (2017)......... ..................... 24 648 \4\ 2,640 \4\ 4 6 2 10 30
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 1 To account for potential El Ni[ntilde]o conditions, take calculated from at-sea densities for California sea lion has been increased by a factor
of 10.
\2\ Take is not calculated by activity type for these species with a low potential to occur, only a yearly total is given.
\2\ Piles of this type may also be installed with an impact hammer, which would reduce the estimated take.
\3\ This total assumes that 36-inch steel piles are used for the Embarcadero Plaza.
Description of Marine Mammals in the Area of the Specified Activity
Harbor Seals
Monitoring of marine mammals in the vicinity of the SFOBB has been
ongoing for 15 years; from those data, Caltrans has produced at-sea
density estimates for Pacific harbor seal of 0.78 animals per square
mile (0.3 animals per square kilometer) for the summer season
(Caltrans, 2015b). Using this density, the potential average daily take
for the areas over which the Level B harassment thresholds may be
exceeded are estimated in Table 8.
Table 8--Take Calculation for Harbor Seal
----------------------------------------------------------------------------------------------------------------
Activity Pile type Density Area (km\2\) Take estimate
----------------------------------------------------------------------------------------------------------------
Vibratory driving................. 24-in steel pile..... 0.78 (0.3 animal/ 38.09 780
km\2\).
Vibratory driving and extraction.. 36-in steel pile..... 0.78 (0.3 animal/ 86.52 1,690; 26
km\2\).
Vibratory extraction.............. Wood and concrete 0.78 (0.3 animal/ 1.27 30
piles. km\2\).
Vibratory driving................. Wood piles........... 0.78 (0.3 animal/ 0.14 10
km\2\).
----------------------------------------------------------------------------------------------------------------
A total of 1,756 harbor seal takes are estimated for 2016 (Table
7).
California sea lion
Monitoring of marine mammals in the vicinity of the SFOBB has been
ongoing for 15 years; from those data, Caltrans has produced at-sea
density estimates for California sea lion of 0.31 animals per square
mile (0.12 animal per square kilometer) for the summer season
(Caltrans, 2015b). Using this density, the potential average daily take
for the areas over which the Level B harassment thresholds may be
exceeded (Table 10) is estimated in Table 9.
Table 9--Take Calculation for California Sea Lion
----------------------------------------------------------------------------------------------------------------
Activity Pile type Density Area (km\2\) Take estimate
----------------------------------------------------------------------------------------------------------------
Vibratory driving and extraction.. 24-in steel pile..... 0.31 (0.12 animal/ 38.09 * 3,250
km\2\).
[[Page 33238]]
Vibratory driving and extraction.. 36-in steel pile..... 0.31 (0.12 animal/ 86.52 * 7,150; 110
km\2\).
Vibratory extraction.............. Wood and concrete 0.31 (0.12 animal/ 1.27 * 300
piles. km\2\).
Vibratory driving................. Wood piles........... 0.31 (0.12 animal/ 0.14 * 100
km\2\).
----------------------------------------------------------------------------------------------------------------
* All California sea lion estimates were multiplied by 10 to account for the increased occurrence of this
species due to El Ni[ntilde]o.
All California sea lion estimates were multiplied by 10 to account
for the increased occurrence of this species due to El Ni[ntilde]o. A
total of 7,660 California sea lion takes is estimated for 2016 (Table
7).
Northern Elephant Seal
Monitoring of marine mammals in the vicinity of the SFOBB has been
ongoing for 15 years; from those data, Caltrans has produced an
estimated at-sea density for northern elephant seal of 0.16 animal per
square mile (0.03 animal per square kilometer) (Caltrans, 2015b). Most
sightings of northern elephant seal in San Francisco Bay occur in
spring or early summer, and are less likely to occur during the periods
of in-water work for this project (June/July through November). As a
result, densities during pile driving for the proposed action would be
much lower. Therefore, we estimate that it is possible that a lone
northern elephant seal may enter the Level B harassment area once per
week during pile driving, for a total of 14 takes in 2016 (Table 7).
Northern Fur Seal
During the breeding season, the majority of the worldwide
population is found on the Pribilof Islands in the southern Bering Sea,
with the remaining animals spread throughout the North Pacific Ocean.
On the coast of California, small breeding colonies are present at San
Miguel Island off southern California, and the Farallon Islands off
central California (Caretta et al 2014). Northern fur seal are a
pelagic species and are rarely seen near the shore away from breeding
areas. Juveniles of this species occasionally strand in San Francisco
Bay, particularly during El Ni[ntilde]o events, for example, during the
2006 El Ni[ntilde]o event, 33 fur seals were admitted to the Marine
Mammal Center (TMMC, 2016). Some of these stranded animals were
collected from shorelines in San Francisco Bay. Due to the recent El
Ni[ntilde]o event, Northern fur seals are being observed in San
Francisco bay more frequently, as well as strandings all along the
California coast and inside San Francisco Bay; a trend that is expected
to continue this summer through winter (TMMC, personal communication).
Because sightings are normally rare; instances recently have been
observed, but are not common, and based on estimates from local
observations (TMMC, personal communication), it is estimated that ten
Norther fur seals will be taken in 2016 (Table 7).
Harbor Porpoise
In the last six decades, harbor porpoises were observed outside of
San Francisco Bay. The few harbor porpoises that entered were not
sighted past central Bay close to the Golden Gate Bridge. In recent
years, however, there have been increasingly common observations of
harbor porpoises in central, north, and south San Francisco Bay.
Porpoise activity inside San Francisco Bay is thought to be related to
foraging and mating behaviors (Keener, 2011; Duffy, 2015). According to
observations by the Golden Gate Cetacean Research team as part of their
multi-year assessment, over 100 porpoises may be seen at one time
entering San Francisco Bay; and over 600 individual animals are
documented in a photo-ID database. However, sightings are concentrated
in the vicinity of the Golden Gate Bridge and Angel Island, north of
the project area, with lesser numbers sighted south of Alcatraz and
west of Treasure Island (Keener 2011). Harbor porpoise generally travel
individually or in small groups of two or three (Sekiguchi, 1995).
Monitoring of marine mammals in the vicinity of the SFOBB has been
ongoing for 15 years; from those data, Caltrans has produced an
estimated at-sea density for harbor porpoise of 0.01 animal per square
mile (0.004 animal per square kilometer) (Caltrans, 2015b). However,
this estimate would be an overestimate of what would actually be seen
in the project area. In order to estimate a more realistic take number,
we assume it is possible that a small group of individuals (three
harbor porpoises) may enter the Level B harassment area on as many as
two days of pile driving, for a total of six harbor porpoise takes per
year (Table 7).
Gray Whale
Historically, gray whales were not common in San Francisco Bay. The
Oceanic Society has tracked gray whale sightings since they began
returning to San Francisco Bay regularly in the late 1990s. The Oceanic
Society data show that all age classes of gray whales are entering San
Francisco Bay, and that they enter as singles or in groups of up to
five individuals. However, the data do not distinguish between
sightings of gray whales and number of individual whales (Winning,
2008). Caltrans Richmond-San Rafael Bridge project monitors recorded 12
living and two dead gray whales in the surveys performed in 2012. All
sightings were in either the central or north Bay; and all but two
sightings occurred during the months of April and May. One gray whale
was sighted in June, and one in October (the specific years were
unreported). It is estimated that two to six gray whales enter San
Francisco Bay in any given year. Because construction activities are
only occurring during a maximum of 106 days in 2016, it is estimated
that two gray whales may potentially enter the area during the
construction period, for a total of 2 gray whale takes in 2016 (Table
7).
Bottlenose Dolphin
Since the 1982-83 El Ni[ntilde]o, which increased water
temperatures off California, bottlenose dolphins have been consistently
sighted along the central California coast (Caretta et al 2008). The
northern limit of their regular range is currently the Pacific coast
off San Francisco and Marin County, and they occasionally enter San
Francisco Bay, sometimes foraging for fish in Fort Point Cove, just
east of the Golden Gate Bridge. In the summer of 2015, a lone
bottlenose dolphin was seen swimming in the Oyster Point area of South
San Francisco (GGCR, 2016). Members of this stock are transient and
make movements up and down the coast, and into some estuaries,
throughout the year. Due to the recent El Ni[ntilde]o event, bottlenose
dolphins are being observed in San Francisco bay more frequently (TMMC,
personal communication). Groups with an average group size of five
animals enter
[[Page 33239]]
the bay and occur near Yerba Buena Island once per week for a two week
stint and then depart the bay (TMMC, personal communication). Assuming
groups of five individuals may enter San Francisco Bay approximately
three times during the construction activities, we estimate 30 takes of
bottlenose dolphins for 2016 (Table 7).
Analyses and Preliminary Determinations
Negligible Impact Analysis
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.'' 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, we consider other factors, such as the likely nature of any
responses (e.g., intensity, duration), the context of any responses
(e.g., critical reproductive time or location, migration), as well as
the number and nature of estimated Level A harassment takes, the number
of estimated mortalities, and effects on habitat.
Pile driving activities associated with the ferry terminal
construction project, as outlined previously, have the potential to
disturb or displace marine mammals. Specifically, the specified
activities may result in take, in the form of Level B harassment
(behavioral disturbance) only, from underwater sounds generated from
pile driving. Potential takes could occur if individuals of these
species are present in the ensonified zone when pile driving occurs.
No injury, serious injury, or mortality is anticipated given the
nature of the activities and measures designed to minimize the
possibility of injury to marine mammals. The potential for these
outcomes is minimized through the construction method and the
implementation of the planned mitigation measures. Specifically,
vibratory hammers will be the primary method of installation (impact
driving is included only as a contingency), and this activity does not
have the potential to cause injury to marine mammals due to the
relatively low source levels produced (less than 180 dB) and the lack
of potentially injurious source characteristics. Impact pile driving
produces short, sharp pulses with higher peak levels and much sharper
rise time to reach those peaks. If impact driving is necessary,
implementation of soft start and shutdown zones significantly reduces
any possibility of injury. Given sufficient ``notice'' through use of
soft start (for impact driving), marine mammals are expected to move
away from a sound source that is annoying prior to it becoming
potentially injurious. WETA will also employ the use of 12-inch-thick
wood cushion block on impact hammers, and use a bubble curtain as sound
attenuation devices. Environmental conditions in San Francisco Ferry
Terminal mean that marine mammal detection ability by trained observers
is high, enabling a high rate of success in implementation of shutdowns
to avoid injury.
WETA's proposed activities are localized and of relatively short
duration (a maximum of 106 days for pile driving in the first year).
The entire project area is limited to the San Francisco ferry terminal
area and its immediate surroundings. These localized and short-term
noise exposures may cause short-term behavioral modifications in harbor
seals, Northern fur seals, Northern elephant seals, California sea
lions, harbor porpoises, bottlenose dolphins, and gray whales.
Moreover, the proposed mitigation and monitoring measures are expected
to reduce the likelihood of injury and behavior exposures.
Additionally, no important feeding and/or reproductive areas for marine
mammals are known to be within the ensonified area during the
construction time frame.
The project also is not expected to have significant adverse
effects on affected marine mammals' habitat. The project activities
would not modify existing marine mammal habitat for a significant
amount of time. The activities may cause some fish to leave the area of
disturbance, thus temporarily impacting marine mammals' foraging
opportunities in a limited portion of the foraging range; but, because
of the short duration of the activities and the relatively small area
of the habitat that may be affected, the impacts to marine mammal
habitat are not expected to cause significant or long-term negative
consequences.
Effects on individuals that are taken by Level B harassment, on the
basis of reports in the literature as well as monitoring from other
similar activities, will likely be limited to reactions such as
increased swimming speeds, increased surfacing time, or decreased
foraging (if such activity were occurring) (e.g., Thorson and Reyff,
2006; Lerma, 2014). Most likely, individuals will simply move away from
the sound source and be temporarily displaced from the areas of pile
driving, although even this reaction has been observed primarily only
in association with impact pile driving. Repeated exposures of
individuals to levels of sound that may cause Level B harassment are
unlikely to result in hearing impairment or to significantly disrupt
foraging behavior due to the small ensonification area and relatively
short duration of the project. Thus, even repeated Level B harassment
of some small subset of the overall stock is unlikely to result in any
significant realized decrease in fitness for the affected individuals,
and thus would not result in any adverse impact to the stock as a
whole.
In summary, this negligible impact analysis is founded on the
following factors: (1) the possibility of injury, serious injury, or
mortality may reasonably be considered discountable; (2) the
anticipated instances of Level B harassment consist of, at worst,
temporary modifications in behavior; (3) the presumed efficacy of the
proposed mitigation measures in reducing the effects of the specified
activity to the level of least practicable impact, and (4) the lack of
important areas. In addition, these stocks are not listed under the
ESA. In combination, we believe that these factors, as well as the
available body of evidence from other similar activities, demonstrate
that the potential effects of the specified activity will have only
short-term effects on individuals. The specified activity is not
reasonably expected to and is not reasonably likely to adversely affect
the marine mammal species or stocks through effects on annual rates of
recruitment or survival, and will therefore not result in population-
level impacts.
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 proposed monitoring and
mitigation measures, we preliminarily find that the total marine mammal
take from WETA's ferry terminal construction activities will have a
negligible impact on the affected marine mammal species or stocks.
Small Numbers Analysis
Table 10 details the number of instances that animals could be
exposed to received noise levels that could cause Level B behavioral
harassment for the
[[Page 33240]]
proposed work at the ferry terminal project site relative to the total
stock abundance. The numbers of animals authorized to be taken for all
species would be considered small relative to the relevant stocks or
populations even if each estimated instance of take occurred to a new
individual--an extremely unlikely scenario. The total percent of the
population (if each instance was a separate individual) for which take
is requested is approximately nine percent for bottlenose dolphins,
approximately six percent for harbor seals, less than three percent for
California sea lions, and less than one percent for all other species
(Table 10). For pinnipeds, especially harbor seals occurring in the
vicinity of the ferry terminal, there will almost certainly be some
overlap in individuals present day-to-day, and the number of
individuals taken is expected to be notably lower. We preliminarily
find that small numbers of marine mammals will be taken relative to the
populations of the affected species or stocks.
Table 10--Estimated Numbers and Percentage of Stock That May Be Exposed to Level B Harassment
----------------------------------------------------------------------------------------------------------------
Proposed Stock(s) Percentage of
Species authorized abundance total stock
takes estimate \1\ (%)
----------------------------------------------------------------------------------------------------------------
Harbor Seal (Phoca vitulina) California stock................... 1,756 30,968 5.7
California sea lion (Zalophus californianus) U.S. Stock......... 7,660 296,750 2.6
Northern elephant seal (Mirounga anustirostris) California 14 179,000 .0008
breeding stock.................................................
Northern fur seal (Callorhinus ursinus) California stock........ 10 14,050 .007
Harbor Porpoise (Phocoena phocoena) San Francisco-Russian River 6 9,886 .006
Stock..........................................................
Gray whale (Eschrichtius robustus) Eastern North Pacific stock.. 2 20,990 .001
Bottlenose dolphin (Tursiops truncatus) California coastal stock 30 323 9.3
----------------------------------------------------------------------------------------------------------------
\1\ All stock abundance estimates presented here are from the draft 2015 Pacific Stock Assessment Report.
Impact on Availability of Affected Species for Taking for Subsistence
Uses
There are no relevant subsistence uses of marine mammals implicated
by this action. Therefore, we have determined that the total taking of
affected species or stocks would not have an unmitigable adverse impact
on the availability of such species or stocks for taking for
subsistence purposes.
Endangered Species Act (ESA)
No marine mammal species listed under the ESA are expected to be
affected by these activities. Therefore, we have determined that
section 7 consultation under the ESA is not required.
National Environmental Policy Act (NEPA)
NMFS is currently conducting an analysis, pursuant to National
Environmental Policy Act (NEPA), to determine whether or not this
proposed activity may have a significant effect on the human
environment. This analysis will be completed prior to the issuance or
denial of this proposed IHA.
Proposed Authorization
As a result of these preliminary determinations, we propose to
authorize the take of marine mammals incidental to WETA's Downtown San
Francisco Ferry Terminal Expansion Project, South Basin Improvements
Project, provided the previously mentioned mitigation, monitoring, and
reporting requirements are incorporated. Specific language from the
proposed IHA is provided next.
This section contains a draft of the IHA. The wording contained in
this section is proposed for inclusion in the IHA (if issued).
1. This Incidental Harassment Authorization (IHA) is valid for one
year from the date of issuance.
2. This IHA is valid only for pile driving activities associated
with the Downtown San Francisco Ferry Terminal Expansion Project, South
Basin Improvements Project in San Francisco Bay, CA.
3. General Conditions.
(a) A copy of this IHA must be in the possession of WETA, its
designees, and work crew personnel operating under the authority of
this IHA.
(b) The species authorized for taking are summarized in Table 1.
(c) The taking, by Level B harassment only, is limited to the
species listed in condition 3(b). See Table 1 for numbers of take
authorized.
Table 1--Authorized Take Numbers
------------------------------------------------------------------------
Authorized take
Species ---------------------
Level A Level B
------------------------------------------------------------------------
Harbor seal....................................... 0 1,756
California sea lion............................... 0 7,660
Northern elephant seal............................ 0 14
Northern fur seal................................. 0 10
Harbor porpoise................................... 0 6
Gray whale........................................ 0 2
Bottlenose dolphin................................ 0 30
---------------------
Total......................................... 0 9,478
------------------------------------------------------------------------
(d) The taking by injury (Level A harassment), serious injury, or
death of the species listed in condition 3(b) of the Authorization or
any taking of any other species of marine mammal is prohibited and may
result in the modification, suspension, or revocation of this IHA.
(e) WETA shall conduct briefings between construction supervisors
and crews, marine mammal monitoring team, and WETA staff prior to the
start of all pile driving activity, and when new personnel join the
work.
4. Mitigation Measures.
The holder of this Authorization is required to implement the
following mitigation measures:
(a) For all pile driving, WETA shall implement a minimum shutdown
zone of 10 m radius around the pile. If a marine mammal comes within or
approaches the shutdown zone, such operations shall cease.
(b) For in-water heavy machinery work other than pile driving
(e.g., standard barges, tug boats, barge-mounted excavators, or
clamshell equipment used to place or remove material), if a marine
mammal comes within 10 meters, operations shall cease and vessels shall
reduce speed to the minimum level required to maintain steerage and
safe working conditions.
(c) WETA shall establish monitoring locations as described below.
Please also refer to the Marine Mammal Monitoring Plan (see
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm).
i. For all pile driving activities, a minimum of two observers
shall be deployed, with one positioned to achieve optimal monitoring of
the shutdown zone and the second positioned to achieve optimal
monitoring of surrounding waters of the ferry terminal and portions of
San Francisco Bay. If practicable, the second
[[Page 33241]]
observer should be deployed to an elevated position with clear sight
lines to the ferry terminal.
ii. These observers shall record all observations of marine
mammals, regardless of distance from the pile being driven, as well as
behavior and potential behavioral reactions of the animals.
Observations within the ferry terminal shall be distinguished from
those in the nearshore waters of San Francisco Bay.
iii. All observers shall be equipped for communication of marine
mammal observations amongst themselves and to other relevant personnel
(e.g., those necessary to effect activity delay or shutdown).
(c) Monitoring shall take place from fifteen minutes prior to
initiation of pile driving activity through thirty minutes post-
completion of pile driving activity. In the event of a delay or
shutdown of activity resulting from marine mammals in the shutdown
zone, animals shall be allowed to remain in the shutdown zone (i.e.,
must leave of their own volition) and their behavior shall be monitored
and documented. Monitoring shall occur throughout the time required to
drive a pile. The shutdown zone must be determined to be clear during
periods of good visibility (i.e., the entire shutdown zone and
surrounding waters must be visible to the naked eye).
(d) If a marine mammal approaches or enters the shutdown zone, all
pile driving activities at that location shall be halted. If pile
driving is halted or delayed due to the presence of a marine mammal,
the activity may not commence or resume until either the animal has
voluntarily left and been visually confirmed beyond the shutdown zone
or fifteen minutes have passed without re-detection of the animal.
(e) Using delay and shut-down procedures, if a species for which
authorization has not been granted (including but not limited to
Guadalupe fur seals and humpback whales) or if a species for which
authorization has been granted but the authorized takes are met,
approaches or is observed within the Level B harassment zone,
activities will shut down immediately and not restart until the animals
have been confirmed to have left the area.
(f) Monitoring shall be conducted by qualified observers, as
described in the Monitoring Plan. Trained observers shall be placed
from the best vantage point(s) practicable to monitor for marine
mammals and implement shutdown or delay procedures when applicable
through communication with the equipment operator. Observer training
must be provided prior to project start and in accordance with the
monitoring plan, and shall include instruction on species
identification (sufficient to distinguish the species listed in 3(b)),
description and categorization of observed behaviors and interpretation
of behaviors that may be construed as being reactions to the specified
activity, proper completion of data forms, and other basic components
of biological monitoring, including tracking of observed animals or
groups of animals such that repeat sound exposures may be attributed to
individuals (to the extent possible).
(g) WETA shall use soft start techniques recommended by NMFS for
impact pile driving. Soft start requires contractors to provide an
initial set of strikes at reduced energy, followed by a thirty-second
waiting period, then two subsequent reduced energy strike sets. Soft
start shall be implemented at the start of each day's impact pile
driving and at any time following cessation of impact pile driving for
a period of thirty minutes or longer.
(h) Sound attenuation devices--Approved sound attenuation devices
(e.g. bubble curtain, pile cushion) shall be used during impact pile
driving operations. WETA shall implement the necessary contractual
requirements to ensure that such devices are capable of achieving
optimal performance, and that deployment of the device is implemented
properly such that no reduction in performance may be attributable to
faulty deployment.
(i) Pile driving shall only be conducted during daylight hours.
5. Monitoring.
The holder of this Authorization is required to conduct marine
mammal monitoring during pile driving activity. Marine mammal
monitoring and reporting shall be conducted in accordance with the
Monitoring Plan.
(a) WETA shall collect sighting data and behavioral responses to
pile driving for marine mammal species observed in the region of
activity during the period of activity. All observers shall be trained
in marine mammal identification and behaviors, and shall have no other
construction-related tasks while conducting monitoring.
(b) For all marine mammal monitoring, the information shall be
recorded as described in the Monitoring Plan.
6. Reporting.
The holder of this Authorization is required to:
(a) Submit a draft report on all monitoring conducted under the IHA
within ninety days of the completion of marine mammal monitoring, or
sixty days prior to the issuance of any subsequent IHA for projects at
the San Francisco Ferry Terminal, whichever comes first. A final report
shall be prepared and submitted within thirty days following resolution
of comments on the draft report from NMFS. This report must contain the
informational elements described in the Monitoring Plan, at minimum
(see www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), and
shall also include:
i. Detailed information about any implementation of shutdowns,
including the distance of animals to the pile and description of
specific actions that ensued and resulting behavior of the animal, if
any.
ii. Description of attempts to distinguish between the number of
individual animals taken and the number of incidents of take, such as
ability to track groups or individuals.
iii. An estimated total take estimate extrapolated from the number
of marine mammals observed during the course of construction
activities, if necessary.
(b) Reporting injured or dead marine mammals:
i. In the unanticipated event that the specified activity clearly
causes the take of a marine mammal in a manner prohibited by this IHA,
such as an injury (Level A harassment), serious injury, or mortality,
WETA shall immediately cease the specified activities and report the
incident to the Office of Protected Resources, NMFS, and the Southwest
Regional Stranding Coordinator, NMFS. The report must include the
following information:
A. Time and date of the incident;
B. Description of the incident;
C. Environmental conditions (e.g., wind speed and direction,
Beaufort sea state, cloud cover, and visibility);
D. Description of all marine mammal observations in the 24 hours
preceding the incident;
E. Species identification or description of the animal(s) involved;
F. Fate of the animal(s); and
G. Photographs or video footage of the animal(s).
Activities shall not resume until NMFS is able to review the
circumstances of the prohibited take. NMFS will work with WETA to
determine what measures are necessary to minimize the likelihood of
further prohibited take and ensure MMPA compliance. WETA may not resume
their activities until notified by NMFS.
ii. In the event that WETA discovers an injured or dead marine
mammal, and the lead observer determines that the cause of the injury
or death is unknown and the death is relatively recent (e.g., in less
than a moderate state of
[[Page 33242]]
decomposition), WETA shall immediately report the incident to the
Office of Protected Resources, NMFS, and the Southwest Regional
Stranding Coordinator, NMFS.
The report must include the same information identified in 6(b)(i)
of this IHA. Activities may continue while NMFS reviews the
circumstances of the incident. NMFS will work with WETA to determine
whether additional mitigation measures or modifications to the
activities are appropriate.
iii. In the event that discovers an injured or dead marine mammal,
and the lead observer determines that the injury or death is not
associated with or related to the activities authorized in the IHA
(e.g., previously wounded animal, carcass with moderate to advanced
decomposition, scavenger damage), WETA shall report the incident to the
Office of Protected Resources, NMFS, and the Southwest Regional
Stranding Coordinator, NMFS, within 24 hours of the discovery. WETA
shall provide photographs or video footage or other documentation of
the stranded animal sighting to NMFS.
7. This Authorization may be modified, suspended or withdrawn if
the holder fails to abide by the conditions prescribed herein, or if
NMFS determines the authorized taking is having more than a negligible
impact on the species or stock of affected marine mammals.
Request for Public Comments
We request comment on our analyses, the draft authorization, and
any other aspect of this Notice of Proposed IHAs for WETA's ferry
terminal construction activities. Please include with your comments any
supporting data or literature citations to help inform our final
decision on WETA's request for an MMPA authorization.
Dated: May 19, 2016.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 2016-12299 Filed 5-24-16; 8:45 am]
BILLING CODE 3510-22-P