25408 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

preliminary review, NMFS intends to 

issue an EFP. Possible conditions the 

agency may impose on this permit, if it 

is granted, include but are not limited 

to, a prohibition of collection of 

specimens within marine protected 

areas, marine sanctuaries, special 

management zones, or artificial reefs 

without additional authorization. 

Additionally, NMFS prohibits the 

possession of Nassau grouper, goliath 

grouper, red snapper, speckled hind or 

warsaw grouper, and requires any sea 

turtles taken incidentally during the 

course of fishing or scientific research 

activities to be handled with due care to 

prevent injury to live specimens, 

observed for activity, and returned to 

the water. 

A final decision on issuance of the 

EFP will depend on NMFS’ review of 

public comments received on the 

application, consultations with the 

affected states, the Council, and the U.S. 

Coast Guard, as well as a determination 

that the EFP is consistent with all 

applicable laws. 

Authority: 16 U.S.C. 1801 et seq. 

Dated: April 25, 2012. 

Emily H. Menashes, 

Acting Director, Office of Sustainable 

Fisheries, National Marine Fisheries Service. 

[FR Doc. 2012–10372 Filed 4–27–12; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XB150 

International Whaling Commission; 

64th Annual Meeting; Announcement 

of Public Meetings 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice of public meeting. 

SUMMARY: This notice announces the 

date, time, and location of the public 

meeting being held prior to the 64th 

annual International Whaling 

Commission (IWC) meeting. 

DATES: The public meeting will be held 

June 5, 2012, at 2 p.m. 

ADDRESSES: The meeting will be held in 

the NOAA Science Center Room, 1301 

East-West Highway, Silver Spring, MD 

20910. 

FOR FURTHER INFORMATION CONTACT: 

Melissa Andersen, 301–427–8385. 

SUPPLEMENTARY INFORMATION: The 

Secretary of Commerce is responsible 

for discharging the domestic obligations 

of the United States under the 

International Convention for the 

Regulation of Whaling, 1946. The U.S. 

IWC Commissioner has responsibility 

for the preparation and negotiation of 

U.S. positions on international issues 

concerning whaling and for all matters 

involving the IWC. The U.S. IWC 

Commissioner is staffed by the 

Department of Commerce and assisted 

by the Department of State, the 

Department of the Interior, the Marine 

Mammal Commission, and other U.S. 

Government agencies. 

A draft agenda for the annual IWC 

meeting should be posted on the IWC 

Secretariat’s Web site at http:// 

www.iwcoffice.org by late May. 

NOAA will a hold public meeting to 

discuss the tentative U.S. positions for 

the upcoming IWC meeting. Because the 

meeting will address U.S. positions, the 

substance of the meeting must be kept 

confidential. Any U.S. citizen with an 

identifiable interest in U.S. whale 

conservation policy may participate, but 

NOAA reserves the authority to inquire 

about the interests of any person who 

appears at the meeting and to determine 

the appropriateness of that person’s 

participation. In particular, persons who 

represent foreign interests may not 

attend. These stringent measures are 

necessary to protect the confidentiality 

of U.S. negotiating positions. 

The June 5, 2012, meeting will be 

held in the NOAA Science Center 

Room, 1301 East-West Highway, Silver 

Spring, MD 20910. Photo identification 

is required to enter the building. 

Special Accommodations 

The meeting is physically accessible 

to people with disabilities. Requests for 

sign language interpretation or other 

auxiliary aids should be directed to 

Melissa Andersen, 

Melissa.Andersen@noaa.gov or 301– 

427–8385, by May 23, 2012. 

Dated: April 24, 2012. 

Rebecca J. Lent, 

Director, Office of International Affairs, 

National Marine Fisheries Service. 

[FR Doc. 2012–10374 Filed 4–27–12; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XB146 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to a Pile 

Replacement 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 an 

application from the U.S. Navy (Navy) 

for an Incidental Harassment 

Authorization (IHA) to take marine 

mammals, by harassment, incidental to 

construction activities as part of a pile 

replacement project. Pursuant to the 

Marine Mammal Protection Act 

(MMPA), NMFS is requesting comments 

on its proposal to issue an IHA to the 

Navy to take, by Level B Harassment 

only, six species of marine mammals 

during the specified activity. 

DATES: Comments and information must 

be received no later than May 30, 2012. 

ADDRESSES: Comments on the 

application should be addressed to 

Tammy C. Adams, Acting Chief, Permits 

and Conservation Division, Office of 

Protected Resources, National Marine 

Fisheries Service, 1315 East-West 

Highway, Silver Spring, MD 20910– 

3225. The mailbox address for providing 

email comments is ITP.Laws@noaa.gov. 

NMFS is not responsible for email 

comments sent to addresses other than 

the one provided here. Comments sent 

via email, including all attachments, 

must not exceed a 10-megabyte file size. 

Instructions: All comments received 

are a part of the public record and will 

generally be posted to http:// 

www.nmfs.noaa.gov/pr/permits/ 

incidental.htm without change. All 

Personal Identifying Information (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. 

An electronic copy of the application 

containing a list of the references used 

in this document may be obtained by 

writing to the address specified above, 

telephoning the contact listed below 

(see FOR FURTHER INFORMATION CONTACT), 

or visiting the Internet at: http:// 

www.nmfs.noaa.gov/pr/permits/ 

incidental.htm. Documents cited in this 

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Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 25409 

notice may also be viewed, by 

appointment, during regular business 

hours, at the aforementioned address. 

FOR FURTHER INFORMATION CONTACT: Ben 

Laws, Office of Protected Resources, 

NMFS, (301) 427–8401. 

SUPPLEMENTARY INFORMATION: 

Background 

Sections 101(a)(5)(A) and (D) of the 

MMPA (16 U.S.C. 1361 et seq.) direct 

the Secretary of Commerce to allow, 

upon request, the incidental, but not 

intentional, taking of small numbers of 

marine mammals by U.S. citizens who 

engage in a specified activity (other than 

commercial fishing) within a specified 

geographical region if certain findings 

are made and either regulations are 

issued or, if the taking is limited to 

harassment, a notice of a proposed 

authorization is provided to the public 

for review. 

Authorization for incidental takings 

shall be granted if NMFS finds that the 

taking will have a negligible impact on 

the species or stock(s), will not have an 

unmitigable adverse impact on the 

availability of the species or stock(s) for 

subsistence uses (where relevant), and if 

the permissible methods of taking and 

requirements pertaining to the 

mitigation, monitoring and reporting of 

such takings are set forth. NMFS has 

defined ‘‘negligible impact’’ in 50 CFR 

216.103 as ‘‘* * * an impact resulting 

from the specified activity that cannot 

be reasonably expected to, and is not 

reasonably likely to, adversely affect the 

species or stock through effects on 

annual rates of recruitment or survival.’’ 

Section 101(a)(5)(D) of the MMPA 

established an expedited process by 

which citizens of the U.S. can apply for 

an authorization to incidentally take 

small numbers of marine mammals by 

harassment. Section 101(a)(5)(D) 

establishes a 45-day time limit for 

NMFS review of an application 

followed by a 30-day public notice and 

comment period on any proposed 

authorizations for the incidental 

harassment of marine mammals. Within 

45 days of the close of the comment 

period, NMFS must either issue or deny 

the authorization. Except with respect to 

certain activities not pertinent here, the 

MMPA defines ‘‘harassment’’ as: ‘‘any 

act of pursuit, torment, or annoyance 

which (i) has the potential to injure a 

marine mammal or marine mammal 

stock in the wild [Level A harassment]; 

or (ii) has the potential to disturb a 

marine mammal or marine mammal 

stock in the wild by causing disruption 

of behavioral patterns, including, but 

not limited to, migration, breathing, 

nursing, breeding, feeding, or sheltering 

[Level B harassment].’’ 

Summary of Request 

NMFS received an application on 

March 8, 2012 from the Navy for the 

taking of marine mammals incidental to 

pile removal and removal in association 

with a pile replacement project in the 

Hood Canal at Naval Base Kitsap at 

Bangor, WA (NBKB). This pile 

replacement project is proposed to 

occur between July 16, 2012 and July 

15, 2013. This IHA would cover the 

second and final year of this project; 

NMFS previously issued an IHA for the 

first year of work associated with this 

project (76 FR 30130; May 24, 2011). Inwater work, including all pile removal 

activities, would occur only within an 

approved window from July 16– 

February 15. Seven species of marine 

mammals are known from the waters 

surrounding NBKB: Steller sea lions 

(Eumetopias jubatus), California sea 

lions (Zalophus californianus), harbor 

seals (Phoca vitulina), killer whales 

(Orcinus orca; transient type only), 

Dall’s porpoises (Phocoenoides dalli), 

harbor porpoises (Phocoena phocoena), 

and the humpback whale (Megaptera 

novaeangliae). These species may occur 

year-round in the Hood Canal, with the 

exception of the Steller sea lion, which 

is present only from fall to late spring 

(October to mid-April), and the 

California sea lion, which is not present 

during part of summer (late June 

through July). Additionally, while the 

Southern resident killer whale (listed as 

endangered under the Endangered 

Species Act [ESA]) is resident to the 

inland waters of Washington and British 

Columbia, it has not been observed in 

the Hood Canal in over 15 years and 

was therefore excluded from further 

analysis. 

NBKB provides berthing and support 

services for OHIO Class ballistic missile 

submarines (SSBN), also known as 

TRIDENT submarines. The Navy 

proposes to complete necessary repairs 

and maintenance at the Explosive 

Handling Wharf #1 (EHW–1) facility at 

NBKB as part of a pile replacement 

project to restore and maintain the 

structural integrity of the wharf and 

ensure its continued functionality to 

support necessary operational 

requirements. The EHW–1 facility, 

constructed in 1977, has become 

compromised due to the deterioration of 

the wharf’s existing piling sub-structure. 

Under the proposed action, ninety-six 

24-in (0.6-m) diameter concrete piles, 

twenty-one 12-in (0.3-m) diameter steel 

fender piles, eight 16-in (0.4-m) 

diameter steel falsework piles, and one 

24-in diameter steel fender pile will be 

removed. The proposed action 

represents the remainder of work 

planned for the initial 2-year 

rehabilitation plan, following the work 

that was completed in 2011. The Navy 

may continue rehabilitation work at 

EHW–1 in the long-term, but has no 

immediate plans to do so. All concrete 

piles would be removed via pneumatic 

chipping or similar method. All steel 

piles would be removed via vibratory 

hammer or direct pull; however, the 

analysis in this document assumes that 

all piles would be removed via vibratory 

hammer. No pile installation—and 

therefore no impact pile removal—is 

proposed for this action. 

For pile removal activities, the Navy 

used NMFS-promulgated thresholds for 

assessing impacts (NMFS, 2005b, 2009), 

outlined later in this document. The 

Navy used recommended spreading loss 

formulas (the practical spreading loss 

equation for underwater sounds and the 

spherical spreading loss equation for 

airborne sounds) and empiricallymeasured source levels from 18- to 30- 

in (0.5- to 0.8-m) diameter steel pile 

removal events, or concrete pile removal 

events using similar methodology, to 

estimate potential marine mammal 

exposures. Predicted exposures are 

outlined later in this document. The 

calculations predict that no Level A 

harassments would occur associated 

with pile removal activities, and that as 

many as 1,416 Level B harassments may 

occur during the pile replacement 

project from generation of underwater 

sound. No incidents of harassment were 

predicted from airborne sounds 

associated with pile removal. 

Description of the Specified Activity 

NBKB is located on the Hood Canal 

approximately 20 miles (32 km) west of 

Seattle, Washington (see Figures 2–1 

through 2–3 in the Navy’s application). 

NBKB provides berthing and support 

services for OHIO Class ballistic missile 

submarines (SSBN), also known as 

TRIDENT submarines. The Navy 

proposes a pile replacement project to 

maintain the structural integrity of 

EHW–1 and ensure its continued 

functionality to support operational 

requirements of the TRIDENT 

submarine program. The proposed 

actions with the potential to cause 

harassment of marine mammals within 

the waterways adjacent to NBKB, under 

the MMPA, are vibratory and pneumatic 

chipping pile removal operations 

associated with the pile replacement 

project. The proposed activities that 

would be authorized by this IHA would 

occur between July 16, 2012 and 

February 15, 2013. All in-water 

construction activities within the Hood 

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25410 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

Canal are only permitted during July 

16–February 15 in order to protect 

spawning fish populations. 

As part of the Navy’s sea-based 

strategic deterrence mission, the Navy 

Strategic Systems Programs directs 

research, development, manufacturing, 

test, evaluation, and operational support 

for the TRIDENT Fleet Ballistic Missile 

program. Maintenance and development 

of necessary facilities for handling of 

explosive materials is part of these 

duties. The proposed action includes 

the removal of 126 steel and concrete 

piles at EHW–1. Please see Figures 1–1 

through 1–3 of the Navy’s application 

for conceptual and schematic 

representations of the work proposed for 

EHW–1. Of the piles requiring removal, 

96 are 24-in (0.6-m) diameter hollow 

pre-cast concrete piles which will be 

excised down to the mud line. One 

additional 24-in steel fender pile, 

twenty-one 12-in (0.3-m) steel fender 

piles, and eight 16-in (0.4-m) steel 

falsework piles will be extracted using 

a vibratory hammer or direct pull. Also 

included in the repair work is removal 

of the fragmentation barrier and 

walkway, construction of new cast-inplace pile caps (concrete formwork may 

be located below Mean Higher High 

Water [MHHW]), installation of the prestressed superstructure, installation of 

four sled-mounted cathodic protection 

(CP) systems, and installation or reinstallation of related appurtenances. 

During the first year of work, 

conducted under an IHA issued by 

NMFS (76 FR 30130; May 24, 2011), the 

Navy completed the following work: 

• Removal of ten steel fender piles 

(eight 12-in diameter piles and two 24- 

in diameter piles) and associated fender 

system components. A fender pile, 

typically set beside slips or wharves, 

guides approaching vessels and is 

driven so as to yield slightly when 

struck in order to lessen the shock of 

contact. The fender system components 

attach the fender piles to the structure, 

and are above the water line. 

• Installation of twenty-eight 30-in 

diameter steel piles and eight 16-in 

diameter steel falsework piles. These 

eight falsework piles would be removed 

in 2012. 

In addition, the Navy plans to 

complete construction of six cast-inplace concrete pile caps in early 2012. 

Pile caps are situated on the tops of the 

steel piles located directly beneath the 

structure, and function as a load transfer 

mechanism between the superstructure 

and the piles. This work is above-water, 

and does not have the potential to 

impact marine mammals. 

During the 2012–13 in-water work 

season, the Navy proposes to complete 

the 2-year rehabilitation project, 

including the following work: 

• Removal of 126 steel and concrete 

piles, as described previously. 

• Removal of the concrete 

fragmentation barrier and walkway, 

used to get from the Wharf Apron to the 

Outboard Support. These structures will 

likely be removed by cutting the 

concrete into sections (potentially three 

or four in total) using a saw, or other 

equipment, and removed using a crane. 

The crane will lift the sections from the 

existing piles and place them on a barge. 

• Installation of a pre-stressed 

concrete superstructure. The 

superstructure is the concrete deck of 

the wharf found above, or supported by, 

the caps or sills, including the deck, 

girders, and stringers. 

• Installation of three sled-mounted 

passive CP systems. The passive CP 

system is a metallic rod or anode that 

is attached to a metal object to protect 

it from corrosion. The anode is 

composed of a more active metal than 

that on which it is mounted and is more 

easily oxidized, thus corroding first and 

acting as a barrier against corrosion for 

the object to which it is attached. This 

system would be banded to the steel 

piles to prevent metallic surfaces of the 

wharf from corroding due to the saline 

conditions in Hood Canal. 

• Installation or re-installation of 

related appurtenances, the associated 

parts of the superstructure that connect 

the superstructure to the piles. These 

pieces include components such as 

bolts, welded metal hangers and fittings, 

brackets, etc. 

Concrete piles would be removed 

with a pneumatic chipping hammer or 

another tool capable of cutting through 

concrete. A pneumatic chipping 

hammer is similar to a jackhammer or 

other similar electric power tool, but 

uses compressed air instead of 

electricity, and consists of a steel piston 

that is reciprocated in a steel barrel. On 

its forward stroke the piston strikes the 

end of the chisel, reciprocating at a rate 

such that the chisel edge vibrates 

against the concrete with enough force 

to fragment or splinter the pile. When 

possible, piles will be first scored by a 

diver using a smaller pneumatic 

hammer, with the pile then moved 

slightly back and forth to break at the 

score. Remaining parts of the pile will 

be chipped away with the larger 

pneumatic hammer. If the scoring/ 

breaking technique is not feasible, the 

entire base of the pile will be chipped 

away with a pneumatic hammer such 

that the pile may be removed. Concrete 

debris will be captured as practicable 

using debris curtains/sheeting and 

removed from the project area. 

The installation of the concrete pile 

caps, the concrete superstructure, and 

sled-mounted passive CP systems will 

occur out of the water and on the tops 

of the piles or attached to the wharf’s 

superstructure. The removal of the 

fragmentation barrier and walkway will 

occur above the water with best 

management practices in place to 

prevent material from entering the 

water. While sound transmission from 

these activities could occur and enter 

the water, this is expected to be 

minimal, and above-water work is not 

considered to have the potential to 

impact marine mammals. However, 

these activities will occur during the inwater work window of July 16 to 

February 15 to minimize the potential 

for impacts to other listed species, 

particularly fish. The Navy will conduct 

acoustic monitoring for pneumatic 

chipping only—acoustic monitoring was 

conducted in 2011 for vibratory pile 

installation at NBKB—and will monitor 

the presence and behavior of marine 

mammals during vibratory pile removal 

and pneumatic chipping activities. 

The Navy estimates that steel pile 

removal will occur at an average rate of 

two piles per day, and is expected to 

require no more than 1 hour per pile. It 

is estimated that concrete pile removal 

will occur at a rate of three piles per 

day, and is expected to take 

approximately 2 hours per pile. This 

results in an estimated maximum of 2 

hours per day of steel pile removal, and 

potentially 6 hours per day of 

pneumatic chipping. These two 

activities would likely not occur on the 

same day, however. On the basis of 

these estimates, the Navy states that 

steel pile removal would require 15 

days and concrete pile removal would 

require an additional 32 days. The 

analysis contained herein is thus based 

upon these numbers, and assumes that 

(1) all marine mammals available to be 

incidentally taken within the relevant 

area would be; and (2) individual 

marine mammals may only be 

incidentally taken once in a 24-hour 

period—for purposes of authorizing 

specified numbers of take—regardless of 

actual number of exposures in that 

period. 

The number of construction barges 

(derrick and material) on site at any one 

time would vary depending on the type 

of construction taking place. Tug boats 

would tow barges to and from the 

construction site and position the barges 

for construction activity. Tug boats 

would leave the site once these tasks 

were completed and so would not be on 

site for extended periods. Smaller skifftype boats would be on site performing 

various functions in support of 

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Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 25411 

construction and monitoring 

requirements. 

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 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 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 SPLs (SPLs; the sound force 

per unit area), sound is referenced in the 

context of underwater sound pressure to 

1 microPascal (mPa). One pascal is the 

pressure resulting from a force of one 

newton exerted over an area of one 

square meter. The source level 

represents the sound level at a distance 

of 1 m from the source (referenced to 1 

mPa). The received level is the sound 

level at the listener’s position. 

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, 1975). 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. 

Underwater sound levels (‘ambient 

sound’) are comprised of multiple 

sources, including 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). Even in the absence of 

anthropogenic sound, the sea is 

typically a loud environment. A number 

of sources of sound are likely to occur 

within Hood Canal, 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 noise 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 (5.3 mi) from shore showing an 

increase of 10 dB in the 100 to 700 Hz 

band during heavy surf conditions. 

• Precipitation noise: Noise 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 noise: 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 noise: 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 (Richardson et 

al., 1995). 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 will attenuate 

(decrease) rapidly (Richardson et al., 

1995). 

In-water construction activities 

associated with the project would 

include vibratory pile removal and 

pneumatic chipping of concrete piles. 

The sounds produced by these activities 

are considered non-pulsed (defined in 

next paragraph) as opposed to pulsed 

sounds. The distinction between these 

two general 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 sounds (e.g., explosions, 

gunshots, sonic booms, and impact pile 

removal) are brief, broadband, atonal 

transients (ANSI, 1986; Harris, 1998) 

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 decay period that may 

include a period of diminishing, 

oscillating maximal and minimal 

pressures. Pulsed sounds generally have 

an increased capacity to induce physical 

injury as compared with sounds that 

lack these features. 

Non-pulse (intermittent or continuous 

sounds) can be tonal, broadband, or 

both. Some of these non-pulse sounds 

can be transient signals of short 

duration but without the essential 

properties of pulses (e.g., rapid rise 

time). Examples of non-pulse sounds 

include those produced by vessels, 

aircraft, machinery operations such as 

drilling or dredging, vibratory pile 

removal, and active sonar systems. The 

duration of such sounds, as received at 

a distance, can be greatly extended in a 

highly reverberant environment. 

Vibratory hammers install or remove 

piles by vibrating them—thus causing 

liquefaction of the surrounding 

substrate—which then allows the piles 

to be more easily pushed or pulled. 

Vibratory hammers produce 

significantly less sound than impact 

hammers. Peak SPLs during vibratory 

installation may be 180 dB or greater, 

but are generally 10 to 20 dB lower than 

SPLs generated during impact pile 

removal of the same-sized pile (Caltrans, 

2009). Rise time is slower, reducing the 

probability and severity of injury 

(USFWS, 2009), and sound energy is 

distributed over a greater amount of 

time (Nedwell and Edwards, 2002; 

Carlson et al., 2001). 

Ambient Sound 

The underwater acoustic environment 

consists of ambient sound, defined as 

environmental background sound levels 

lacking a single source or point 

(Richardson et al., 1995). The ambient 

underwater sound level of a region is 

defined by the total acoustical energy 

being generated by known and 

unknown sources, including sounds 

from both natural and anthropogenic 

sources. The sum of the various natural 

and anthropogenic sound sources at any 

given location and time depends not 

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25412 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

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, the ambient 

sound levels at a given frequency and 

location can vary by 10–20 dB from day 

to day (Richardson et al., 1995). 

In the vicinity of the project area, the 

average broadband ambient underwater 

sound levels were measured at 114 dB 

re 1mPa between 100 Hz and 20 kHz 

(Slater, 2009). Peak spectral sound from 

industrial activity was noted below the 

300 Hz frequency, with maximum levels 

of 110 dB re 1mPa noted in the 125 Hz 

band. In the 300 Hz to 5 kHz range, 

average levels ranged between 83–99 dB 

re 1mPa. Wind-driven wave sound 

dominated the background sound 

environment at approximately 5 kHz 

and above, and ambient sound levels 

flattened above 10 kHz. 

Airborne sound levels at NBKB vary 

based on location but are estimated to 

average around 65 dBA (A-weighted 

decibels) in the residential and office 

park areas, with traffic sound ranging 

from 60–80 dBA during daytime hours 

(Cavanaugh and Tocci, 1998). The 

highest levels of airborne sound are 

produced along the waterfront and at 

the ordnance handling areas, where 

estimated sound levels range from 70– 

90 dBA and may peak at 99 dBA for 

short durations. These higher sound 

levels are produced by a combination of 

sound sources including heavy trucks, 

forklifts, cranes, marine vessels, 

mechanized tools and equipment, and 

other sound-generating industrial or 

military activities. 

Sound Thresholds 

Since 1997, NMFS has used generic 

sound exposure thresholds to determine 

when an activity in the ocean that 

produces sound might result in impacts 

to a marine mammal such that a take by 

harassment might occur (NMFS, 2005b). 

To date, no studies have been 

conducted that examine impacts to 

marine mammals from pile removal 

sounds from which empirical sound 

thresholds have been established. 

Current NMFS practice regarding 

exposure of marine mammals to sound 

is that cetaceans and pinnipeds exposed 

to sound levels of 180 and 190 dB rms 

or above, respectively, are considered to 

have been taken by Level A (i.e., 

injurious) harassment. Behavioral 

harassment (Level B) is considered to 

have occurred when marine mammals 

are exposed to sounds at or above 120 

dB rms for continuous sound (such as 

would be produced by the proposed 

activities), but below injurious 

thresholds. For airborne sound, 

pinniped disturbance from haul-outs 

has been documented at 100 dB 

(unweighted) for pinnipeds in general, 

and at 90 dB (unweighted) for harbor 

seals. NMFS uses these levels as 

guidelines to estimate when harassment 

may occur. 

Distance to Sound Thresholds 

Underwater Sound Propagation 

Formula—Pile removal would generate 

underwater noise that potentially could 

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. A 

practical sound propagation modeling 

technique was used by the Navy to 

estimate the range from the activity to 

various SPL thresholds in water. This 

model follows a geometric propagation 

loss based on the distance from the pile, 

resulting in a 4.5 dB reduction in level 

for each doubling of distance from the 

source. In this model, the SPL at some 

distance away from the source (e.g., 

driven pile) is governed by a measured 

source level, minus the transmission 

loss of the energy as it dissipates with 

distance. The formula for underwater 

TL is: 

TL = 15 * log10(R1/R2), where 

R1 = the distance of the modeled SPL from 

the pile, and 

R2 = the distance from the pile of the initial 

measurement. 

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]). The propagation 

environment along the NBKB waterfront 

conforms to neither spherical nor 

cylindrical spreading; as the receiver 

moves away from the shoreline, the 

water increases in depth, resulting in an 

expected propagation environment that 

would lie between spherical and 

cylindrical spreading loss conditions. 

Since there is no available data 

regarding propagation loss along the 

NBKB waterfront, a practical spreading 

loss model was adopted as the most 

likely approximation of the sound 

propagation environment. 

Hydroacoustic monitoring results from 

the Navy’s Test Pile Project (see 76 FR 

38361; July 30, 2011) and from the first 

year of EHW–1 construction will be 

used, when available, to confirm the 

validity of the practical spreading model 

for estimating acoustic propagation in 

the project area. 

Underwater Sound from Pile 

Removal—The intensity of pile removal 

sounds is greatly influenced by factors 

such as the type of piles, hammers, and 

the physical environment in which the 

activity takes place. Despite a large 

quantity of literature regarding SPLs 

recorded from pile removal projects, 

there is a general lack of empirical data 

regarding vibratory pile removal and the 

acoustic output of chipping hammers. In 

order to determine reasonable SPLs and 

their associated affects on marine 

mammals that are likely to result from 

pile removal at NBKB, studies with 

similar properties to the proposed 

action were evaluated. Overall, studies 

which met the following parameters 

were considered: (1) Pile size and 

materials: Steel pipe pile removal (12- 

to 24-in diameter) and concrete pile 

removal with chipping hammer or 

similar method (because these tools are 

used to chip portions of concrete from 

the pile, sound output is not tied to pile 

size); (2) Hammer machinery: Vibratory 

hammer for steel piles and pneumatic 

chipping hammer or similar tool for 

concrete piles; and (3) Physical 

environment: Shallow depth (less than 

100 ft [30 m]). Table 1 details 

representative SPLs that have been 

recorded from similar construction 

activities in recent years. Due to the 

similarity of these actions and the 

Navy’s proposed action, these values 

represent reasonable SPLs which could 

be anticipated, and which were used in 

the acoustic modeling and analysis. 

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TABLE 1—REPRESENTATIVE UNDERWATER SPLS FOR PILE REMOVAL

Project and 

location Pile size and type Removal method Water depth Measured SPLs 

California (location not 

specified).

24-in steel pipe pile ........... Vibratory hammer ............. ∼15 m (49 ft) ..................... 165 dB re: 1 μPa (rms) at 

10 m (33 ft) 

United Kingdom (location 

not specified).

Concrete (size not specified).Jackhammer ...................... Unknown ........................... 161 dB re: 1 μPa (rms) at 

1 m (3.3 ft) 

Sources: Caltrans, 2007; Nedwell and Howell, 2004. 

Based on these representative SPLs, 

the source levels used in this analysis 

are 180 dB re: 1 mPa (rms) for vibratory 

removal and 161 dB re: 1 mPa (rms) for 

pneumatic chipping, which is 

considered analogous to the 

jackhammer. Therefore, vibratory 

removal would produce SPLs that are 

below the injury threshold for 

pinnipeds, while SPLs resulting from 

pneumatic chipping are well below 

levels that may cause injury to any 

marine mammal. All calculated 

distances to and the total area 

encompassed by the marine mammal 

underwater sound thresholds are 

provided in Table 2. 

TABLE 2—CALCULATED DISTANCE(S) TO AND AREA ENCOMPASSED BY UNDERWATER MARINE MAMMAL SOUND

THRESHOLDS

Threshold Distance Area, km2

(mi2) 

Vibratory removal, cetacean injury (180 dB) ................................................................................................ 1 m (3.3 ft) 0.000003 

(0.000001) 

Vibratory removal, disturbance (120 dB) ...................................................................................................... 10,000 m (32,808 ft) 314 (121) 

Pneumatic chipping, disturbance (120 dB) ................................................................................................... 542 m (1,778 ft) 0.9 (0.4) 

The values presented in Tables 2 

assume a field free of obstruction, which 

is unrealistic, because Hood Canal does 

not represent open water conditions 

(free field). Therefore, sounds would 

attenuate as they encounter land masses 

or bends in the canal. As a result, some 

of the distances and areas of impact 

calculated cannot actually be attained at 

the project area. The actual distances to 

the behavioral disturbance thresholds 

for vibratory pile removal and 

pneumatic chipping may be shorter than 

those calculated due to the irregular 

contour of the waterfront, the 

narrowness of the canal, and the 

maximum fetch (furthest distance sound 

waves travel without obstruction [i.e., 

line of sight]) at the project area. The 

actual areas encompassed by sound 

exceeding or reaching the 120 dB 

threshold are 35.9 km2 and 0.6 km2 for 

vibratory removal and pneumatic 

chipping, respectively. See Figures 6–1 

and 6–2 of the Navy’s application for a 

depiction of the size of areas in which 

each underwater sound threshold is 

predicted to occur at the project area 

due to pile removal. 

Airborne Sound Propagation 

Formula—Pile removal can generate 

airborne sound that could potentially 

result in disturbance to marine 

mammals (specifically, pinnipeds) 

which are hauled out or at the water’s 

surface. As a result, the Navy analyzed 

the potential for pinnipeds hauled out 

or swimming at the surface near NBKB 

to be exposed to airborne SPLs that 

could result in Level B behavioral 

harassment. The appropriate airborne 

sound threshold for behavioral 

disturbance for all pinnipeds, except 

harbor seals, is 100 dB re: 20 mPa rms 

(unweighted). For harbor seals, the 

threshold is 90 dB re: 20 mPa rms 

(unweighted). A spherical spreading 

loss model, assuming average 

atmospheric conditions, was used to 

estimate the distance to the airborne 

thresholds. The formula for calculating 

spherical spreading loss is: 

TL = 20log(R1/R2) 

TL = Transmission loss 

R1 = the distance of the modeled SPL from 

the pile, and 

R2 = the distance from the pile of the initial 

measurement. 

Airborne Sound from Pile 

Installation—As was discussed for 

underwater sound from pile removal, 

the intensity of pile removal sounds is 

greatly influenced by factors such as the 

type of piles, hammers, and the physical 

environment in which the activity takes 

place. In order to determine reasonable 

airborne SPLs and their associated 

effects on marine mammals that are 

likely to result from pile removal at 

NBKB, studies with similar properties to 

the proposed action, as described 

previously, were evaluated. Table 3 

details representative pile removal 

activities that have occurred in recent 

years. Due to the similarity of these 

actions and the Navy’s proposed action, 

they represent reasonable SPLs which 

could be anticipated. Given these data, 

representative source levels are 

approximately 116.5 dB re: 20 mPa rms 

(unweighted) for vibratory removal and 

112 dB re: 20 mPa rms (unweighted) for 

chipping. 

TABLE 3—REPRESENTATIVE AIRBORNE SPLS

Project and 

location Pile size and type Method Water depth Measured SPLs 

Wahkiakum Ferry Terminal, WA.18-in (0.5 m) steel pipe 

pile.

Vibratory ............................ ∼ 3–4 m (10–12 ft) ............ 87.5 dB re: 20 μPa (rms) 

at 50 ft (15.2 m) 

Keystone Ferry Terminal, 

WA.

30-in (0.8 m) steel pipe 

pile.

Vibratory ............................ ∼ 9 m (30 ft) ...................... 98 dB re: 20 μPa (rms) at 

36 ft (10.9 m) 

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25414 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

TABLE 3—REPRESENTATIVE AIRBORNE SPLS—Continued 

Project and 

location Pile size and type Method Water depth Measured SPLs 

Not specified ...................... Concrete, size not specified.Chipping hammer .............. Unknown ........................... 92 dB re: 20 μPa (rms) at 

10 m (33 ft) 

Sources: WSDOT, 2010; Cheremisinoff, 1996. 

The distances to the airborne 

thresholds were calculated with the 

airborne transmission loss formula 

presented previously. All calculated 

distances to and the total area 

encompassed by the marine mammal 

underwater sound thresholds are 

provided in Table 4. 

TABLE 4—CALCULATED DISTANCE(S) TO AND AREA ENCOMPASSED BY AIRBORNE MARINE MAMMAL SOUND THRESHOLDS

Threshold Distance Area, km2 (mi2) 

Vibratory removal, pinniped disturbance (100 dB) .......................................................................... 7 m (23 ft) 0.0002 (0.0001) 

Vibratory removal, harbor seal disturbance (90 dB) ....................................................................... 20 m (66 ft) 0.001 (0.0005) 

Pneumatic chipping, pinniped disturbance (100 dB) ....................................................................... 4 m (13 ft) 0.00005 (0.00002) 

Pneumatic chipping, harbor seal disturbance (90 dB) .................................................................... 13 m (43 ft) 0.0005 (0.0002) 

All airborne distances are less than 

those calculated for underwater sound 

thresholds for disturbance. Protective 

measures would be in place out to the 

distances calculated for the underwater 

thresholds, and the distances for the 

airborne thresholds would be covered 

fully by mitigation and monitoring 

measures in place for underwater sound 

thresholds. Construction sound 

associated with the project would not 

extend beyond the disturbance zone for 

underwater sound that would be 

established to protect pinnipeds. No 

haul-outs or rookeries are located within 

the airborne harassment radii. See 

Figures 6–3 through 6–6 of the Navy’s 

application for a depiction of the size of 

areas in which each airborne sound 

threshold is predicted to occur at the 

project area due to pile removal. 

Description of Marine Mammals in the 

Area of the Specified Activity 

There are seven marine mammal 

species, four cetaceans and three 

pinnipeds, which may inhabit or transit 

through the waters nearby NBKB in the 

Hood Canal. These include the transient 

killer whale, harbor porpoise, Dall’s 

porpoise, Steller sea lion, California sea 

lion, harbor seal, and humpback whale. 

While the Southern Resident killer 

whale is resident to the inland waters of 

Washington and British Columbia, it has 

not been observed in the Hood Canal in 

over 15 years, and therefore was 

excluded from further analysis. The 

Steller sea lion and humpback whale are 

the only marine mammals that may 

occur within the Hood Canal that are 

listed under the ESA; the humpback 

whale is listed as endangered and the 

eastern distinct population segment 

(DPS) of Steller sea lion is listed as 

threatened. All marine mammal species 

are protected under the MMPA. This 

section summarizes the population 

status and abundance of these species, 

followed by detailed life history 

information. Table 5 lists the marine 

mammal species that occur in the 

vicinity of NBKB and their estimated 

densities within the project area during 

the proposed timeframe. Daily 

maximum abundance data only is 

presented for sea lions because sightings 

data have no defined survey area. 

TABLE 5—MARINE MAMMALS THAT MAY BE PRESENT IN THE HOOD CANAL

Species Stock abundance 1 Relative occurrence in 

Hood Canal 2 Season of occurrence 

Density during 

in-water work season 

(individuals/ 

km2) 

Steller sea lion—Eastern U.S. 

DPS.

58,334–72,223 3 ........ Common ..................................... Fall to late spring (Oct to midApril).

4 1.2 

California sea lion—U.S. stock ... 238,000 ..................... Common ..................................... Fall to late spring (Aug to early 

June).

4 26.2 

Harbor seal—WA inland waters 

stock.

14,612 (CV = 0.15) ... Common ..................................... Year-round; resident species in 

Hood Canal.

5 1.31 

Humpback whale—CA/OR/WA 

stock.

2,043 (CV = 0.10) ..... Extremely rare ............................ Year-round in Puget Sound ....... 6 0.003 

Killer whale—West Coast transient stock.354 ............................ Rare ........................................... Year-round ................................. 7 0.038 

Dall’s porpoise—CA/OR/WA 

stock.

42,000 (CV = 0.33) ... Rare ........................................... Year-round ................................. 7 0.014 

Harbor porpoise—WA inland 

waters stock.

10,682 (CV = 0.38) ... Possible common to occasional 

presence.

Year-round ................................. 9 0.250 

1 NMFS marine mammal stock assessment reports at: http://www.nmfs.noaa.gov/pr/sars/species.htm. 2 Common: Consistently present either year-round or during non-breeding season; Occasional: Documented at irregular intervals; Rare: Sporadic sightings not occurring on a yearly basis; Extremely rare: Generally not observed over multiple years. 3 Range calculated on basis of total pup counts 2006–2009 and extrapolation factors derived from vital rate parameters estimated for an increasing population. 

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4 Density for sea lions is not calculated due to the lack of a defined survey area for sightings data. Abundance calculated as the average of the 

maximum number of individuals present during shore-based surveys at NBKB waterfront during the in-water construction season. 5 Jeffries et al., 2003; Huber et al., 2001. 6 Density calculated on the basis of one individual observed in Hood Canal. 

7 Density calculated as the maximum number of individuals present at a given time during occurrences of killer whales at Hood Canal in 2003 

and 2005 (London, 2006) divided by the area of Hood Canal. 8 Density calculated from number of individuals observed in 18 vessel-based surveys of NBKB waterfront area (Tannenbaum et al., 2009, 

2011). 9 Density calculated from number of individuals observed during vessel-based surveys conducted during Test Pile Program and corrected for 

detectability (Navy, in prep.). 

Steller Sea Lion 

Species Description—Steller sea lions 

are the largest members of the Otariid 

(eared seal) family. Steller sea lions 

show marked sexual dimorphism, in 

which adult males are noticeably larger 

and have distinct coloration patterns 

from females. Males average 

approximately 1,500 lb (680 kg) and 10 

ft (3 m) in length; females average about 

700 lb (318 kg) and 8 ft (2.4 m) in length. 

Adult females have a tawny to silvercolored pelt. Males are characterized by 

dark, dense fur around their necks, 

giving a mane-like appearance, and light 

tawny coloring over the rest of their 

body (NMFS, 2008a). Steller sea lions 

are distributed mainly around the coasts 

to the outer continental shelf along the 

North Pacific Ocean rim from northern 

Hokkaido, Japan through the Kuril 

Islands and Okhotsk Sea, Aleutian 

Islands and central Bering Sea, southern 

coast of Alaska and south to California. 

The population is divided into the 

Western and the Eastern Distinct 

Population Segments (DPSs) at 144° W 

(Cape Suckling, Alaska). The Western 

DPS includes Steller sea lions that 

reside in the central and western Gulf of 

Alaska, Aleutian Islands, as well as 

those that inhabit coastal waters and 

breed in Asia (e.g., Japan and Russia). 

The Eastern DPS extends from 

California to Alaska, including the Gulf 

of Alaska. 

Status—Steller sea lions were listed 

as threatened range-wide under the ESA 

in 1990. After division into two DPSs, 

the western DPS was listed as 

endangered under the ESA in 1997, 

while the eastern DPS remained 

classified as threatened. Animals found 

in the Region of Activity are from the 

eastern DPS (NMFS, 1997a; Loughlin, 

2002; Angliss and Outlaw, 2005). The 

eastern DPS breeds in rookeries located 

in southeast Alaska, British Columbia, 

Oregon, and California. While some 

pupping has been reported recently 

along the coast of Washington, there are 

no active rookeries in Washington. A 

final revised species recovery plan 

addresses both DPSs (NMFS, 2008a). 

NMFS designated critical habitat for 

Steller sea lions in 1993. Critical habitat 

is associated with breeding and haul-out 

sites in Alaska, California, and Oregon, 

and includes so-called ‘aquatic zones’ 

that extend 3,000 ft (900 m) seaward in 

state and federally managed waters from 

the baseline or basepoint of each major 

rookery in Oregon and California 

(NMFS, 2008a). Three major rookery 

sites in Oregon (Rogue Reef, Pyramid 

Rock, and Long Brown Rock and Seal 

Rock on Orford Reef at Cape Blanco) 

and three rookery sites in California 

(Ano Nuevo I, Southeast Farallon I, and 

Sugarloaf Island and Cape Mendocino) 

are designated critical habitat (NMFS, 

1993). There is no designated critical 

habitat within the Region of Activity. 

Factors that have previously been 

identified as threats to Steller sea lions 

include reduced food availability, 

possibly resulting from competition 

with commercial fisheries; incidental 

take and intentional kills during 

commercial fish harvests; subsistence 

take; entanglement in marine debris; 

disease; pollution; and harassment. 

Steller sea lions are also sensitive to 

disturbance at rookeries (during 

pupping and breeding) and haul-out 

sites. 

The Recovery Plan for the Steller Sea 

Lion (NMFS, 2008a) states that the 

overall abundance of Steller sea lions in 

the eastern DPS has increased for a 

sustained period of at least three 

decades, and that pup production has 

increased significantly, especially since 

the mid-1990s. Between 1977 and 2002, 

researchers estimated that overall 

abundance of the eastern DPS had 

increased at an average rate of 3.1 

percent per year (NMFS, 2008a; Pitcher 

et al., 2007). NMFS’ most recent stock 

assessment report estimates that 

population for the eastern DPS is a 

minimum of 52,847 individuals; this 

estimate is not corrected for animals at 

sea, and actual population is estimated 

to be within the range 58,334 to 72,223 

(Allen and Angliss, 2010). The 

minimum count for Steller sea lions in 

Oregon and Washington was 5,813 in 

2002 (Pitcher et al., 2007; Allen and 

Angliss, 2010). 

The abundance of the eastern DPS of 

Steller sea lions is increasing 

throughout the northern portion of its 

range (southeast Alaska and British 

Columbia), and stable or increasing in 

the central portion (Oregon through 

central California). Surveys indicate that 

pup production in Oregon increased at 

3 percent per year from 1990–2009, 

while pup production in California 

increased at 5 percent per year between 

1996 and 2009, with the number of nonpups reported as stable. The best 

available information indicates that, 

overall, the eastern DPS has increased 

from an estimated 18,040 animals in 

1979 to an estimated 63,488 animals in 

2009; therefore the overall estimated 

rate of increase for this period is 4.3 

percent per year (NMML, 2012). 

In the far southern end of Steller sea 

lion range (Channel Islands in southern 

California), population declined 

significantly after the 1930s—probably 

due to hunting and harassment 

(Bartholomew and Boolootian, 1960; 

Bartholomew, 1967)—and several 

rookeries and haul-outs have been 

abandoned. The lack of recolonization 

at the southernmost portion of the range 

(e.g., San Miguel Island rookery), 

despite stability in the non-pup portion 

of the overall California population, is 

likely a response to a suite of factors, 

including changes in ocean conditions 

(e.g., warmer temperatures) that may be 

contributing to habitat changes that 

favor California sea lions over Steller 

sea lions (NMFS, 2007) and competition 

for space on land, and possibly prey, 

with species that have experienced 

explosive growth over the past three 

decades (California sea lions and 

northern elephant seals [Mirounga 

angustirostris]). Although recovery in 

California has lagged behind the rest of 

the DPS, this portion of the DPS’ range 

has recently shown a positive growth 

rate (NMML, 2012). While non-pup 

counts in California in the 2000s are 

only 34 percent of pre-decline counts 

(1927–47), the population has increased 

significantly since 1990. 

Despite the abandonment of certain 

rookeries in California, pup production 

at other rookeries in California has 

increased over the last 20 years and, 

overall, the eastern DPS has increased at 

an average annual growth rate of 4.3 

percent per year for 30 years. Even 

though these rookeries might not be 

recolonized, their loss has not prevented 

the increasing abundance of Steller sea 

lions in California or in the eastern DPS 

overall. 

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Because the eastern DPS of Steller sea 

lion is currently listed as threatened 

under the ESA, it is therefore designated 

as depleted and classified as a strategic 

stock under the MMPA. However, the 

eastern DPS has been considered a 

potential candidate for removal from 

listing under the ESA by the Steller sea 

lion recovery team and NMFS (NMFS, 

2008), based on observed annual rates of 

increase. Although the stock size has 

increased, the status of this stock 

relative to its Optimum Sustainable 

Population (OSP) size is unknown. The 

overall annual rate of increase of the 

eastern stock has been consistent and 

long-term, and may indicate that this 

stock is reaching OSP. 

Behavior and Ecology—Steller sea 

lions forage near shore and in pelagic 

waters. They are capable of traveling 

long distances in a season and can dive 

to approximately 1,300 ft (400 m) in 

depth. They also use terrestrial habitat 

as haul-out sites for periods of rest, 

molting, and as rookeries for mating and 

pupping during the breeding season. At 

sea, they are often seen alone or in small 

groups, but may gather in large rafts at 

the surface near rookeries and haul-outs. 

Steller sea lions prefer the colder 

temperate to sub-arctic waters of the 

North Pacific Ocean. Haul-outs and 

rookeries usually consist of beaches 

(gravel, rocky or sand), ledges, and 

rocky reefs. In the Bering and Okhotsk 

Seas, sea lions may also haul-out on sea 

ice, but this is considered atypical 

behavior (NOAA, 2010a). 

Steller sea lions are gregarious 

animals that often travel or haul out in 

large groups of up to 45 individuals 

(Keple, 2002). At sea, groups usually 

consist of female and subadult males; 

adult males are usually solitary while at 

sea (Loughlin, 2002). In the Pacific 

Northwest, breeding rookeries are 

located in British Columbia, Oregon, 

and northern California. Steller sea lions 

form large rookeries during late spring 

when adult males arrive and establish 

territories (Pitcher and Calkins, 1981). 

Large males aggressively defend 

territories while non-breeding males 

remain at peripheral sites or haul-outs. 

Females arrive soon after and give birth. 

Most births occur from mid-May 

through mid-July, and breeding takes 

place shortly thereafter. Most pups are 

weaned within a year. Non-breeding 

individuals may not return to rookeries 

during the breeding season but remain 

at other coastal haul-outs (Scordino, 

2006). 

Steller sea lions are opportunistic 

predators, feeding primarily on fish and 

cephalopods, and their diet varies 

geographically and seasonally (Bigg, 

1985; Merrick et al., 1997; Bredesen et 

al., 2006; Guenette et al., 2006). 

Foraging habitat is primarily shallow, 

nearshore and continental shelf waters; 

freshwater rivers; and also deep waters 

(Reeves et al., 2008; Scordino, 2010). 

Steller sea lions occupy major winter 

haul-out sites on the coast of Vancouver 

Island in the Strait of Juan de Fuca and 

the Georgia Basin (Bigg, 1985; Olesiuk, 

2008); the closest breeding rookery to 

the project area is at Carmanah Point 

near the western entrance to the Strait 

of Juan de Fuca. There are no known 

breeding rookeries in Washington 

(NMFS, 1992; Angliss and Outlaw, 

2005) but Eastern stock Steller sea lions 

are present year-round along the outer 

coast of Washington at four major haulout sites (NMFS, 2008a). Both sexes are 

present in Washington waters; these 

animals are likely immature or nonbreeding adults from rookeries in other 

areas (NMFS, 2008a). In Washington, 

Steller sea lions primarily occur at haulout sites along the outer coast from the 

Columbia River to Cape Flattery. In 

inland waters, Steller sea lions use haulout sites along the Vancouver Island 

coastline of the Strait of Juan de Fuca 

(Jeffries et al., 2000; COSEWIC, 2003; 

Olesiuk, 2008). Numbers vary 

seasonally in Washington waters with 

peak numbers present during the fall 

and winter months (Jeffries et al., 2000). 

The highest breeding season Steller sea 

lion count at Washington haul-out sites 

was 847 individuals during the period 

from 1978 to 2001 (Pitcher et al., 2007). 

Non-breeding season surveys of 

Washington haul-out sites reported as 

many as 1,458 individuals between 

1980 and 2001 (NMFS, 2008a). 

Steller sea lions are occasionally 

present at the Toliva Shoals haul-out 

site in south Puget Sound (Jeffries et al., 

2000) and a rock three miles south of 

Marrowstone Island (NMFS, 2010). 

Fifteen Steller sea lions have been 

observed using this haul-out site. At 

NBKB, Steller sea lions have been 

observed hauled out on submarines at 

Delta Pier on several occasions from 

2008 through 2011 during fall through 

spring months (October to April) (Navy 

2010). Other potential haul-out sites 

may include isolated islands, rocky 

shorelines, jetties, buoys, rafts, and 

floats (Jeffries et al., 2000). Steller sea 

lions likely utilize foraging habitats in 

Hood Canal similar to those of the 

California sea lion and harbor seal, 

which include marine nearshore and 

deeper water habitats. 

Acoustics—Like all pinnipeds, the 

Steller sea lion is amphibious; while all 

foraging activity takes place in the 

water, breeding behavior is carried out 

on land in coastal rookeries (Mulsow 

and Reichmuth 2008). On land, 

territorial male Steller sea lions 

regularly use loud, relatively lowfrequency calls/roars to establish 

breeding territories (Schusterman et al., 

1970; Loughlin et al., 1987). The calls of 

females range from 0.03 to 3 kHz, with 

peak frequencies from 0.15 to 1 kHz; 

typical duration is 1.0 to 1.5 sec 

(Campbell et al., 2002). Pups also 

produce bleating sounds. Individually 

distinct vocalizations exchanged 

between mothers and pups are thought 

to be the main modality by which 

reunion occurs when mothers return to 

crowded rookeries following foraging at 

sea (Mulsow and Reichmuth, 2008). 

Mulsow and Reichmuth (2008) 

measured the unmasked airborne 

hearing sensitivity of one male Steller 

sea lion. The range of best hearing 

sensitivity was between 5 and 14 kHz. 

Maximum sensitivity was found at 10 

kHz, where the subject had a mean 

threshold of 7 dB. The underwater 

hearing threshold of a male Steller sea 

lion was significantly different from that 

of a female. The peak sensitivity range 

for the male was from 1 to 16 kHz, with 

maximum sensitivity (77 dB re: 1mPa-m) 

at 1 kHz. The range of best hearing for 

the female was from 16 to above 25 kHz, 

with maximum sensitivity (73 dB re: 

1mPa-m) at 25 kHz. However, because of 

the small number of animals tested, the 

findings could not be attributed to either 

individual differences in sensitivity or 

sexual dimorphism (Kastelein et al., 

2005). 

California Sea Lion 

Species Description—California sea 

lions are members of the Otariid family 

(eared seals). The species, Zalophus 

californianus, includes three 

subspecies: Z. c. wollebaeki (in the 

Galapagos Islands), Z. c. japonicus (in 

Japan, but now thought to be extinct), 

and Z. c. californianus (found from 

southern Mexico to southwestern 

Canada; referred to here as the 

California sea lion) (Carretta et al., 

2007). The California sea lion is 

sexually dimorphic. Males may reach 

1,000 lb (454 kg) and 8 ft (2.4 m) in 

length; females grow to 300 lb (136 kg) 

and 6 ft (1.8 m) in length. Their color 

ranges from chocolate brown in males to 

a lighter, golden brown in females. At 

around five years of age, males develop 

a bony bump on top of the skull called 

a sagittal crest. The crest is visible in the 

dog-like profile of male sea lion heads, 

and hair around the crest gets lighter 

with age. 

Status—The U.S. stock of California 

sea lions is estimated at 238,000 and the 

minimum population size of this stock 

is 141,842 individuals (Carretta et al., 

2007). These numbers are from counts 

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during the 2001 breeding season of 

animals that were ashore at the four 

major rookeries in southern California 

and at haul-out sites north to the 

Oregon/California border. Sea lions that 

were at-sea or hauled-out at other 

locations were not counted (Carretta et 

al., 2007). The stock has likely reached 

its carrying capacity and, even though 

current total human-caused mortality is 

unknown (due to a lack of observer 

coverage in the California set gillnet 

fishery that historically has been the 

largest source of human-caused 

mortalities), California sea lions are not 

considered a strategic stock under the 

MMPA because total human-caused 

mortality is still likely to be less than 

the potential biological removal (PBR). 

An estimated 3,000 to 5,000 California 

sea lions migrate to waters of 

Washington and British Columbia 

during the non-breeding season from 

September to May (Jeffries et al., 2000). 

Peak numbers of up to 1,000 California 

sea lions occur in Puget Sound 

(including Hood Canal) during this time 

period (Jeffries et al., 2000). 

Distribution—The geographic 

distribution of California sea lions 

includes a breeding range from Baja 

California, Mexico to southern 

California. During the summer, 

California sea lions breed on islands 

from the Gulf of California to the 

Channel Islands and seldom travel more 

than about 31 mi (50 km) from the 

islands (Bonnell et al., 1983). The 

primary rookeries are located on the 

California Channel Islands of San 

Miguel, San Nicolas, Santa Barbara, and 

San Clemente (Le Boeuf and Bonnell, 

1980; Bonnell and Dailey, 1993). Their 

distribution shifts to the northwest in 

fall and to the southeast during winter 

and spring, probably in response to 

changes in prey availability (Bonnell 

and Ford, 1987). 

The non-breeding distribution 

extends from Baja California north to 

Alaska for males, and encompasses the 

waters of California and Baja California 

for females (Reeves et al., 2008; 

Maniscalco et al., 2004). In the nonbreeding season, an estimated 3,000– 

5,000 adult and sub-adult males migrate 

northward along the coast to central and 

northern California, Oregon, 

Washington, and Vancouver Island from 

September to May (Jeffries et al., 2000) 

and return south the following spring 

(Mate, 1975; Bonnell et al., 1983). Along 

their migration, they are occasionally 

sighted hundreds of miles offshore 

(Jefferson et al., 1993). Females and 

juveniles tend to stay closer to the 

rookeries (Bonnell et al., 1983). 

California sea lions are present in 

Hood Canal during much of the year 

with the exception of mid-June through 

August, and occur regularly in the 

vicinity of the project site, as observed 

during Navy waterfront surveys 

conducted at NBKB from April 2008 

through June 2010 (Navy, 2010). They 

are known to utilize man-made 

structures such as piers, jetties, offshore 

buoys, log booms, and oil platforms 

(Riedman, 1990), and are often seen 

rafted off of river mouths (Jeffries et al., 

2000). Although there are no regular 

California sea lion haul-outs known 

within the Hood Canal (Jeffries et al., 

2000), they are frequently observed 

hauled out at several opportune areas at 

NBKB (e.g., submarines, floating 

security fence, barges). As many as 58 

California sea lions have been observed 

hauled out together at NBKB (Agness 

and Tannenbaum, 2009a; Tannenbaum 

et al., 2009a; Walters, 2009). California 

sea lions have also been observed 

swimming in the Hood Canal in the 

vicinity of the project area on several 

occasions and likely forage in both 

nearshore marine and inland marine 

deeper waters (DoN, 2001a). 

Behavior and Ecology—California sea 

lions feed on a wide variety of prey, 

including many species of fish and 

squid (Everitt et al., 1981; Roffe and 

Mate, 1984; Antonelis et al., 1990; 

Lowry et al., 1991). In the Puget Sound 

region, they feed primarily on fish such 

as Pacific hake (Merluccius productus), 

walleye pollock (Theragra 

chalcogramma), Pacific herring (Clupea 

pallasii), and spiny dogfish (Squalus 

acanthias) (Calambokidis and Baird, 

1994). In some locations where salmon 

runs exist, California sea lions also feed 

on returning adult and out-migrating 

juvenile salmonids (London, 2006). 

Sexual maturity occurs at around four to 

five years of age for California sea lions 

(Heath, 2002). California sea lions are 

gregarious during the breeding season 

and social on land during other times. 

Acoustics—On land, California sea 

lions make incessant, raucous barking 

sounds; these have most of their energy 

at less than 2 kHz (Schusterman et al., 

1967). Males vary both the number and 

rhythm of their barks depending on the 

social context; the barks appear to 

control the movements and other 

behavior patterns of nearby conspecifics 

(Schusterman, 1977). Females produce 

barks, squeals, belches, and growls in 

the frequency range of 0.25–5 kHz, 

while pups make bleating sounds at 

0.25–6 kHz. California sea lions produce 

two types of underwater sounds: clicks 

(or short-duration sound pulses) and 

barks (Schusterman et al., 1966, 1967; 

Schusterman and Baillet, 1969). All 

underwater sounds have most of their 

energy below 4 kHz (Schusterman et al., 

1967). 

The range of maximal hearing 

sensitivity underwater is between 1–28 

kHz (Schusterman et al., 1972). 

Functional underwater high frequency 

hearing limits are between 35–40 kHz, 

with peak sensitivities from 15–30 kHz 

(Schusterman et al., 1972). The 

California sea lion shows relatively poor 

hearing at frequencies below 1 kHz 

(Kastak and Schusterman, 1998). Peak 

hearing sensitivities in air are shifted to 

lower frequencies; the effective upper 

hearing limit is approximately 36 kHz 

(Schusterman, 1974). The best range of 

sound detection is from 2–16 kHz 

(Schusterman, 1974). Kastak and 

Schusterman (2002) determined that 

hearing sensitivity generally worsens 

with depth—hearing thresholds were 

lower in shallow water, except at the 

highest frequency tested (35 kHz), 

where this trend was reversed. Octave 

band sound levels of 65–70 dB above 

the animal’s threshold produced an 

average temporary threshold shift (TTS; 

discussed later in ‘‘Potential Effects of 

the Specified Activity on Marine 

Mammals’’) of 4.9 dB in the California 

sea lion (Kastak et al., 1999). 

Harbor Seal 

Species Description—Harbor seals, 

which are members of the Phocid family 

(true seals), inhabit coastal and 

estuarine waters and shoreline areas 

from Baja California, Mexico to western 

Alaska. For management purposes, 

differences in mean pupping date (i.e., 

birthing) (Temte, 1986), movement 

patterns (Jeffries, 1985; Brown, 1988), 

pollutant loads (Calambokidis et al., 

1985) and fishery interactions have led 

to the recognition of three separate 

harbor seal stocks along the west coast 

of the continental U.S. (Boveng, 1988). 

The three distinct stocks are: (1) Inland 

waters of Washington (including Hood 

Canal, Puget Sound, and the Strait of 

Juan de Fuca out to Cape Flattery), (2) 

outer coast of Oregon and Washington, 

and (3) California (Carretta et al., 2007). 

The inland waters of Washington stock 

is the only stock that is expected to 

occur within the project area. 

The average weight for adult seals is 

about 180 lb (82 kg) and males are 

slightly larger than females. Male harbor 

seals weigh up to 245 lb (111 kg) and 

measure approximately 5 ft (1.5 m) in 

length. The basic color of harbor seals’ 

coat is gray and mottled but highly 

variable, from dark with light color rings 

or spots to light with dark markings 

(NMFS, 2008c). 

Status—Estimated population 

numbers for the inland waters of 

Washington, including the Hood Canal, 

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Puget Sound, and the Strait of Juan de 

Fuca out to Cape Flattery, are 14,612 

individuals (Carretta et al., 2007). The 

minimum population is 12,844 

individuals. The harbor seal is the only 

species of marine mammal that is 

consistently abundant and considered 

resident in the Hood Canal (Jeffries et 

al., 2003). The population of harbor 

seals in Hood Canal is a closed 

population, meaning that they do not 

have much movement outside of Hood 

Canal (London, 2006). The abundance of 

harbor seals in Hood canal has 

stabilized, and the population may have 

reached its carrying capacity in the mid1990s with an approximate abundance 

of 1,000 harbor seals (Jeffries et al., 

2003). 

Harbor seals are not considered to be 

depleted under the MMPA or listed 

under the ESA. Human-caused mortality 

relative to PBR is unknown, but it is 

considered to be small relative to the 

stock size. Therefore, the Washington 

Inland Waters stock of harbor seals is 

not classified as a strategic stock. 

Distribution—Harbor seals are coastal 

species, rarely found more than 12 mi 

(20 km) from shore, and frequently 

occupy bays, estuaries, and inlets (Baird 

2001). Individual seals have been 

observed several miles upstream in 

coastal rivers. Ideal harbor seal habitat 

includes haul-out sites, shelter during 

the breeding periods, and sufficient food 

(Bjorge, 2002). Haul-out areas can 

include intertidal and subtidal rock 

outcrops, sandbars, sandy beaches, peat 

banks in salt marshes, and man-made 

structures such as log booms, docks, and 

recreational floats (Wilson, 1978; 

Prescott, 1982; Schneider and Payne, 

1983; Gilber and Guldager, 1998; Jeffries 

et al., 2000). Human disturbance can 

affect haul-out choice (Harris et al., 

2003). 

Harbor seals occur throughout Hood 

Canal and are seen relatively commonly 

in the area. They are year-round, nonmigratory residents, and pup (i.e., give 

birth) in Hood Canal. Surveys in the 

Hood Canal from the mid-1970s to 2000 

show a fairly stable population between 

600–1,200 seals (Jeffries et al., 2003). 

Harbor seals have been observed 

swimming in the waters along NBKB in 

every month of surveys conducted from 

2007–2010 (Agness and Tannenbaum, 

2009b; Tannenbaum et al., 2009b). On 

the NBKB waterfront, harbor seals have 

not been observed hauling out in the 

intertidal zone, but have been observed 

hauled-out on man-made structures 

such as the floating security fence, 

buoys, barges, marine vessels, and logs 

(Agness and Tannebaum, 2009a; 

Tannenbaum et al., 2009a). The main 

haul-out locations for harbor seals in 

Hood Canal are located on river delta 

and tidal exposed areas at Quilcene, 

Dosewallips, Duckabush, Hamma 

Hamma, and Skokomish River mouths 

(see Figure 4–1 of the Navy’s 

application), with the closest haul-out 

area to the project area being ten miles 

(16 km) southwest of NBKB at 

Dosewallips River mouth, outside the 

potential area of effect for this project 

(London, 2006). 

Behavior and Ecology—Harbor seals 

are typically seen in small groups 

resting on tidal reefs, boulders, 

mudflats, man-made structures, and 

sandbars. Harbor seals are opportunistic 

feeders that adjust their patterns to take 

advantage of locally and seasonally 

abundant prey (Payne and Selzer 1989; 

Baird 2001; Bj<rge 2002). The harbor 

seal diet consists of fish and 

invertebrates (Bigg, 1981; Roffe and 

Mate, 1984; Orr et al., 2004). Although 

harbor seals in the Pacific Northwest are 

common in inshore and estuarine 

waters, they primarily feed at sea (Orr 

et al., 2004) during high tide. 

Researchers have found that they 

complete both shallow and deep dives 

during hunting depending on the 

availability of prey (Tollit et al., 1997). 

Their diet in Puget Sound consists of 

many of the prey resources that are 

present in the nearshore and deeper 

waters of NBKB, including hake, herring 

and adult and out-migrating juvenile 

salmonids. Harbor seals in Hood Canal 

are known to feed on returning adult 

salmon, including ESA-threatened 

summer-run chum (Oncorhynchus 

keta). Over a 5-year study of harbor seal 

predation in the Hood Canal, the 

average percent escapement of summerrun chum consumed was eight percent 

(London, 2006). 

Harbor seals mate at sea and females 

give birth during the spring and 

summer, although the pupping season 

varies by latitude. In coastal and inland 

regions of Washington, pups are born 

from April through January. Pups are 

generally born earlier in the coastal 

areas and later in the Puget Sound/Hood 

Canal region (Calambokidis and Jeffries, 

1991; Jeffries et al., 2000). Suckling 

harbor seal pups spend as much as forty 

percent of their time in the water 

(Bowen et al., 1999). 

Acoustics—In air, harbor seal males 

produce a variety of low-frequency (less 

than 4 kHz) vocalizations, including 

snorts, grunts, and growls. Male harbor 

seals produce communication sounds in 

the frequency range of 100–1,000 Hz 

(Richardson et al., 1995). Pups make 

individually unique calls for mother 

recognition that contain multiple 

harmonics with main energy below 0.35 

kHz (Bigg, 1981; Thomson and 

Richardson, 1995). Harbor seals hear 

nearly as well in air as underwater and 

had lower thresholds than California sea 

lions (Kastak and Schusterman, 1998). 

Kastak and Schusterman (1998) reported 

airborne low frequency (100 Hz) sound 

detection thresholds at 65.4 dB re 20 

mPa for harbor seals. In air, they hear 

frequencies from 0.25–30 kHz and are 

most sensitive from 6–16 kHz 

(Richardson, 1995; Terhune and 

Turnbull, 1995; Wolski et al., 2003). 

Adult males also produce underwater 

sounds during the breeding season that 

typically range from 0.25–4 kHz 

(duration range: 0.1 s to multiple 

seconds; Hanggi and Schusterman 

1994). Hanggi and Schusteman (1994) 

found that there is individual variation 

in the dominant frequency range of 

sounds between different males, and 

Van Parijs et al. (2003) reported oceanic, 

regional, population, and site-specific 

variation that could be vocal dialects. In 

water, they hear frequencies from 1–75 

kHz (Southall et al., 2007) and can 

detect sound levels as weak as 60–85 dB 

re 1 mPa within that band. They are most 

sensitive at frequencies below 50 kHz; 

above 60 kHz sensitivity rapidly 

decreases. 

Humpback Whale 

Species Description—The humpback 

whale is a baleen whale, and a member 

of the Balaenopterid family (rorquals), 

with a worldwide distribution in all 

ocean basins. Similar to all baleen 

whales, adult females are larger than 

adult males, reaching lengths of up to 60 

ft (18 m). Their body coloration is 

primarily dark grey, but individuals 

have a variable amount of white on their 

pectoral fins and belly. This variation is 

so distinctive that the pigmentation 

pattern on the undersides of their flukes 

is used to identify individual whales. 

Humpback whales are known for their 

long pectoral fins, which can be up to 

15 ft (4.6 m) in length and provide 

significant maneuverability. In the 

summer, most humpback whales are 

found in high latitude or highly 

biologically productive feeding grounds. 

In the winter, they congregate in 

subtropical or tropical waters for 

mating. 

In the North Pacific, there are at least 

three separate populations: (1) CA/OR/ 

WA stock, which winters in coastal 

Central America and Mexico and 

migrates to areas ranging from the coast 

of California to southern British 

Columbia in summer/fall; (2) Central 

North Pacific stock, which winters in 

the Hawaiian Islands and migrates to 

northern British Columbia/Southeast 

Alaska and Prince William Sound west 

to Kodiak; and (3) Western North Pacific 

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stock, which winters near Japan and 

probably migrates to waters west of the 

Kodiak Archipelago (the Bering Sea and 

Aleutian Islands) in summer/fall. 

Though there is some mixing between 

these populations, they are considered 

distinct stocks. The stock structure of 

humpback whales is defined based on 

feeding areas, as distinct populations 

have a high degree of fidelity to specific 

feeding areas. Humpback whales found 

in inland Washington waters are 

members of the CA/OR/WA stock. 

Carretta et al. (2011) described distinct 

feeding populations in the eastern 

Pacific, and the waters off northern 

Washington may be an area of mixing 

between the CA/OR/WA stock and 

British Columbia/Alaska whales, or 

whales in northern Washington and 

southern British Columbia may be a 

distinct feeding population and a 

separate stock. 

Status—Humpback whales were 

listed as endangered under the 

Endangered Species Preservation Act of 

1966 because of declines due to 

commercial whaling. This protection 

was transferred to the ESA in 1973. 

Because of this listing, it is therefore 

designated as depleted and classified as 

a strategic stock under the MMPA. The 

recovery plan for humpback whales was 

finalized in November 1991 (NMFS, 

1991). Critical habitat has not been 

designated for this species. 

Humpback whales are increasing in 

abundance through much of their range, 

including the CA/OR/WA stock. In the 

North Pacific, humpback abundance 

was estimated at fewer than 1,400 

whales in 1966, after heavy commercial 

exploitation. The current abundance 

estimate for the North Pacific is about 

20,000 whales in total. Carretta et al. 

(2011) reported the best estimate for the 

CA/OR/WA stock as 2,043 individuals, 

based on mark-recapture estimates by 

Calambokidis et al. (2009). However, 

this estimate excludes some whales in 

Washington. Population trends from 

mark-recapture estimates have shown 

an overall long-term increase of 

approximately 7.5 percent per year for 

the CA/OR/WA stock (Calambokidis, 

2009). 

Distribution—The worldwide 

population of humpback whales is 

divided into various northern and 

southern ocean populations 

(Mackintosh, 1965). Geographical 

overlap of these populations has been 

documented only off Central America 

(Acevedo and Smultea, 1995; 

Rasmussen et al., 2004, 2007). The 

humpback whale is one of the most 

abundant cetaceans off the Pacific coast 

of Costa Rica during the winter breeding 

season of northern hemisphere 

humpbacks. 

Humpback whales were one of the 

most common large cetaceans in the 

inland waters of Washington prior to the 

early 1900s (Scheffer and Slipp, 1948). 

However, sightings became infrequent 

in Puget Sound and the Georgia Basin 

through the late 1990s, and prior to 

2003 the presence of only three 

individual humpback whales was 

confirmed (Falcone et al., 2005). 

However, in 2003 and 2004, thirteen 

individuals were sighted in the inland 

waters of Washington, mainly during 

the fall (Falcone et al., 2005). Records 

available for 2001 to 2012 include 

observations in the Strait of Juan de 

Fuca; the Gulf Islands and the vicinity 

of Victoria, British Columbia; Admiralty 

Inlet; the San Juan Islands; Hood Canal; 

and Puget Sound (Orca Network, 2012). 

In Hood Canal, several humpback 

whale sightings were recorded 

beginning on January 27, 2012 (Orca 

Network, 2012). Review of the sightings 

information indicates the sightings are 

of a single individual. The most recent 

sighting reported was on February 17, 

2012. It is currently unknown if this 

individual has left Hood Canal. Prior to 

these sightings, there have been no 

confirmed reports of humpback whales 

entering Hood Canal (Calambokidis, 

2012). No other reports of humpback 

whales in the Hood Canal were found in 

the Orca Network database, the 

scientific literature, or agency reports. 

Construction of the Hood Canal Bridge 

occurred in 1961 and could have 

contributed to the lack of historical 

sightings (Calambokidis, 2010). Only a 

few records of humpback whales near 

Hood Canal are in the Orca Network 

database, but these are north of the 

Hood Canal Bridge. 

Behavior and Ecology—Humpback 

whales travel great distances during 

their seasonal migrations from high 

latitude feeding grounds to tropical and 

subtropical breeding grounds. One of 

the more closely studied routes is 

between Alaska and Hawaii, where 

humpbacks have been observed making 

the 3,000 mi (4,830 km) trip in as few 

as 36 days. During the summer months, 

humpbacks spend the majority of their 

time feeding and building up fat 

reserves (blubber) that they will live off 

of during the winter breeding season. 

Humpbacks filter feed on tiny 

crustaceans (mostly krill), plankton, and 

small fish and are known to consume up 

to 3,000 lb (1,360 kg) of food per day. 

Several hunting methods involve using 

air bubbles to herd, corral, or disorient 

fish. One highly complex variant, called 

bubble netting, is unique to humpbacks 

and is often performed in groups with 

defined roles for distracting, scaring, 

and herding before whales lunge at prey 

corralled near the surface. While on 

their winter breeding grounds, 

humpback whales congregate and 

engage in mating activities. Humpbacks 

are generally polygynous, with males 

exhibiting competitive behavior 

including aggressive and antagonistic 

displays. Breeding usually occurs once 

every 2 years, but sometimes occurs 

twice in 3 years. 

Although the humpback whale is 

considered a primarily coastal species, 

it often traverses deep pelagic areas 

while migrating (Clapham and Mattila, 

1990; Norris et al., 1999; Calambokidis 

et al., 2001). During migration, 

humpbacks stay near the surface of the 

ocean, and tend to generally prefer 

shallow waters. During calving, 

humpbacks are usually found in the 

warmest waters available at that 

latitude. Calving grounds are commonly 

near offshore reef systems, islands, or 

continental shores. Humpback feeding 

grounds are in cold, productive coastal 

waters. 

Humpback whales are often sighted 

singly or in groups of two or three, but 

while on breeding and feeding grounds 

they may occur in groups larger than 

twenty (Leatherwood and Reeves, 1983; 

Jefferson et al., 2008). The diving 

behavior of humpback whales is related 

to time of year and whale activity 

(Clapham and Mead, 1999). In summer 

feeding areas, humpbacks typically 

forage in the upper 120 m of the water 

column, with a maximum recorded dive 

depth of 500 m (Dolphin, 1987; Dietz et 

al., 2002). On winter breeding grounds, 

humpback dives have been recorded at 

depths greater than 100 m (Baird et al., 

2000). The CA/OR/WA stock winters in 

coastal Central America and Mexico, 

and the stock migrates to areas ranging 

from the coast of California to southern 

British Columbia in summer and fall. 

Acoustics—Humpback whales, like all 

baleen whales, are considered lowfrequency cetaceans. Functional hearing 

for low-frequency cetaceans is estimated 

to range from 7 Hz to 22 kHz (Southall 

et al., 2007). During the winter breeding 

season, males sing complex songs that 

can last up to 20 minutes and be heard 

at great distance, and may sing for 

hours, repeating the song several times. 

All males in a population sing the same 

song, but that song continually evolves 

over time. 

Killer Whale 

Species Description—Killer whales 

are members of the Delphinid family 

and are the most widely distributed 

cetacean species in the world. Killer 

whales have a distinctive color pattern, 

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with black dorsal and white ventral 

portions. They also have a conspicuous 

white patch above and behind the eye 

and a highly variable gray or white 

saddle area behind the dorsal fin. The 

species shows considerable sexual 

dimorphism. Adult males develop larger 

pectoral flippers, dorsal fins, tail flukes, 

and girths than females. Male adult 

killer whales can reach up to 32 ft 

(9.8 m) in length and weigh nearly 

22,000 lb (10,000 kg); females reach 28 

ft (8.5 m) in length and weigh up to 

16,500 lb (7,500 kg). 

Based on appearance, feeding habits, 

vocalizations, social structure, and 

distribution and movement patterns 

there are three types of populations of 

killer whales (Wiles, 2004; NMFS, 

2005). The three distinct forms or types 

of killer whales recognized in the North 

Pacific Ocean are: (1) Resident, (2) 

Transient, and (3) Offshore. The 

resident and transient populations have 

been divided further into different 

subpopulations based mainly on genetic 

analyses and distribution; not enough is 

known about the offshore whales to 

divide them into subpopulations (Wiles, 

2004). Only transient killer whales are 

known from the project area. 

Transient killer whales occur 

throughout the eastern North Pacific, 

and have primarily been studied in 

coastal waters. Their geographical range 

overlaps that of the resident and 

offshore killer whales. The dorsal fin of 

transient whales tends to be more erect 

(straighter at the tip) than those of 

resident and offshore whales (Ford and 

Ellis, 1999; Ford et al., 2000). Saddle 

patch pigmentation of transient killer 

whales is restricted to two patterns, and 

never has the large areas of black 

pigmentation intruding into the white of 

the saddle patch that is seen in resident 

and offshore types. Transient type 

whales are often found in long-term 

stable social units that tend to be 

smaller than resident social groups (e.g., 

fewer than ten whales); these social 

units do not seem as permanent as 

matrilines are in resident type whales. 

Transient killer whales feed nearly 

exclusively on marine mammals (Ford 

and Ellis, 1999), whereas resident 

whales primarily eat fish. Offshore 

whales are presumed to feed primarily 

on fish, and have been documented 

feeding on sharks. 

Within the transient type, association 

data (Ford et al., 1994; Ford and Ellis, 

1999; Matkin et al., 1999), acoustic data 

(Saulitis, 1993; Ford and Ellis, 1999) 

and genetic data (Hoelzel et al., 1998, 

2002; Barrett-Lennard, 2000) confirms 

that three communities of transient 

whales exist and represent three 

discrete populations: (1) Gulf of Alaska, 

Aleutian Islands, and Bering Sea 

transients, (2) AT1 transients (Prince 

William Sound, AK; listed as depleted 

under the MMPA), and (3) West Coast 

transients. Among the genetically 

distinct assemblages of transient killer 

whales in the northeastern Pacific, only 

the West Coast transient stock, which 

occurs from southern California to 

southeastern Alaska, may occur in the 

project area. 

Status—The West Coast transient 

stock is a trans-boundary stock, with 

minimum counts for the population of 

transient killer whales coming from 

various photographic datasets. 

Combining these counts of cataloged 

transient whales gives a minimum 

number of 354 individuals for the West 

Coast transient stock (Allen and Angliss, 

2010). However, the number in 

Washington waters at any one time is 

probably fewer than 20 individuals 

(Wiles, 2004). The West Coast transient 

killer whale stock is not designated as 

depleted under the MMPA or listed 

under the ESA. The estimated annual 

level of human-caused mortality and 

serious injury does not exceed the PBR. 

Therefore, the West Coast Transient 

stock of killer whales is not classified as 

a strategic stock. Population trends and 

status of this stock relative to its 

Optimum Sustainable Population (OSP) 

level are currently unknown. 

Distribution—The geographical range 

of transient killer whales includes the 

northeast Pacific, with preference for 

coastal waters of southern Alaska and 

British Columbia (Krahn et al., 2002). 

Transient killer whales in the eastern 

North Pacific spend most of their time 

along the outer coast, but visit Hood 

Canal and the Puget Sound in search of 

harbor seals, sea lions, and other prey. 

Transient occurrence in inland waters 

appears to peak during August and 

September (Morton, 1990; Baird and 

Dill, 1995; Ford and Ellis, 1999) which 

is the peak time for harbor seal pupping, 

weaning, and post-weaning (Baird and 

Dill, 1995). In 2003 and 2005, small 

groups of transient killer whales (eleven 

and six individuals, respectively) 

visited Hood Canal to feed on harbor 

seals and remained in the area for 

significant periods of time (59 and 172 

days, respectively) between the months 

of January and July. 

Behavior and Ecology—Transient 

killer whales show greater variability in 

habitat use, with some groups spending 

most of their time foraging in shallow 

waters close to shore while others hunt 

almost entirely in open water (Felleman 

et al., 1991; Baird and Dill, 1995; Matkin 

and Saulitis, 1997). Transient killer 

whales feed on marine mammals and 

some seabirds, but apparently no fish 

(Morton, 1990; Baird and Dill, 1996; 

Ford et al., 1998; Ford and Ellis, 1999; 

Ford et al., 2005). While present in 

Hood Canal in 2003 and 2005, transient 

killer whales preyed on harbor seals in 

the subtidal zone of the nearshore 

marine and inland marine deeper water 

habitats (London, 2006). Other 

observations of foraging transient killer 

whales indicate they prefer to forage on 

pinnipeds in shallow, protected waters 

(Heimlich-Boran, 1988; Saulitis et al., 

2000). Transient killer whales travel in 

small, matrilineal groups, but they 

typically contain fewer than ten animals 

and their social organization generally is 

more flexible than that of resident killer 

whales (Morton, 1990, Ford and Ellis, 

1999). These differences in social 

organization probably relate to 

differences in foraging (Baird and 

Whitehead, 2000). There is no 

information on the reproductive 

behavior of killer whales in this area. 

Acoustics—Killer whales produce a 

wide variety of clicks and whistles, but 

most of their sounds are pulsed, with 

frequencies ranging from 0.5–25 kHz 

(dominant frequency range: 1–6 kHz) 

(Thomson and Richardson, 1995; 

Richardson et al., 1995). Source levels 

of echolocation signals range between 

195–224 dB re 1 mPa-m peak-to-peak 

(p-p), dominant frequencies range from 

20–60 kHz, with durations of about 0.1 

s (Au et al., 2004). Source levels 

associated with social sounds have been 

calculated to range between 131–168 dB 

re 1 mPa-m and vary with vocalization 

type (Veirs, 2004). 

Both behavioral and auditory 

brainstem response techniques indicate 

killer whales can hear in a frequency 

range of 1–100 kHz and are most 

sensitive at 20 kHz. This is one of the 

lowest maximum-sensitivity frequencies 

known among toothed whales 

(Szymanski et al., 1999). 

Dall’s Porpoise 

Species Description—Dall’s porpoises 

are members of the Phocoenid 

(porpoise) family and are common in 

the North Pacific Ocean. They can reach 

a maximum length of just under 8 ft 

(2.4 m) and weigh up to 480 lb (218 kg). 

Males are slightly larger and thicker 

than females, which reach lengths of 

just under 7 ft (2.1 m) long. The body 

of Dall’s porpoises is a very dark gray 

or black in coloration with variable 

contrasting white thoracic panels and 

white ‘frosting’ on the dorsal fin and tail 

that distinguish them from other 

cetacean species. These markings and 

colorations vary with geographic region 

and life stage, with adults having more 

distinct patterns. 

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Based on NMFS stock assessment 

reports, Dall’s porpoises within the 

Pacific U.S. Exclusive Economic Zone 

are divided into two discrete, 

noncontiguous areas: (1) Waters off 

California, Oregon, and Washington, 

and (2) Alaskan waters (Carretta et al., 

2008). Only individuals from the CA/ 

OR/WA stock may occur within the 

project area. 

Status—The NMFS population 

estimate, recently updated in 2010 for 

the CA/OR/WA stock, is 42,000 (CV = 

0.33) which is based on vessel line 

transect surveys by Barlow (2010) and 

Forney (2007). The minimum 

population is considered to be 32,106. 

Additional numbers of Dall’s porpoises 

occur in the inland waters of 

Washington, but the most recent 

estimate was obtained in 1996 (900 

animals; CV = 0.40; Calambokidis et al., 

1997) and is not included in the overall 

estimate of abundance for this stock due 

to the need for more up-to-date 

information. Dall’s porpoise are not 

listed as depleted under the MMPA or 

listed under the ESA. The average 

annual human-caused mortality is 

estimated to be less than the PBR, and 

therefore the stock is not classified as a 

strategic stock under the MMPA. The 

status of Dall’s porpoises in California, 

Oregon and Washington relative to OSP 

is not known, and there are insufficient 

data to evaluate potential trends in 

abundance. 

Distribution—The Dall’s porpoise is 

found from northern Baja California, 

Mexico, north to the northern Bering 

Sea and south to southern Japan 

(Jefferson et al., 1993). The species is 

only common between 32–62° N in the 

eastern North Pacific (Morejohn, 1979; 

Houck and Jefferson, 1999). North-south 

movements in California, Oregon, and 

Washington have been suggested. Dall’s 

porpoises shift their distribution 

southward during cooler-water periods 

(Forney and Barlow, 1998). Norris and 

Prescott (1961) reported finding Dall’s 

porpoises in southern California waters 

only in the winter, generally when the 

water temperature was less than 15°C 

(59 °F). Seasonal movements have also 

been noted off Oregon and Washington, 

where higher densities of Dall’s 

porpoises were sighted offshore in 

winter and spring and inshore in 

summer and fall (Green et al., 1992). 

In Washington, they are most 

abundant in offshore waters. They are 

year-round residents in Washington 

(Green et al., 1992), but their 

distribution is highly variable between 

years, likely due to changes in 

oceanographic conditions (Forney and 

Barlow, 1998). Dall’s porpoises are 

observed throughout the year in the 

Puget Sound north of Seattle (Osborne 

et al., 1998) and are seen occasionally in 

southern Puget Sound. Dall’s porpoises 

may also occasionally occur in Hood 

Canal (Jeffries 2006, personal 

communication). Nearshore habitats 

used by Dall’s porpoises could include 

the marine habitats found in the inland 

marine waters of the Hood Canal. A 

Dall’s porpoise was observed in the 

deeper water at NBKB in summer 2008 

(Tannenbaum et al., 2009a). 

Behavior and Ecology—Dall’s 

porpoises can be opportunistic feeders 

but primarily consume schooling forage 

fish. They are known to eat squid, 

crustaceans, and fishes such as 

blackbelly eelpout (Lycodopsis 

pacifica), herring, pollock, hake, and 

Pacific sandlance (Ammodytes 

hexapterus) (Walker et al., 1998). 

Groups of Dall’s porpoises generally 

include fewer than ten individuals and 

are fluid, probably aggregating for 

feeding (Jefferson, 1990, 1991; Houck 

and Jefferson, 1999). Dall’s porpoises 

become sexually mature at three and a 

half to eight years of age (Houck and 

Jefferson, 1999) and give birth to a 

single calf after ten to twelve months. 

Breeding and calving typically occurs in 

the spring and summer (Angell and 

Balcomb, 1982). In the North Pacific, 

there is a strong summer calving peak 

from early June through August (Ferrero 

and Walker, 1999), and a smaller peak 

in March (Jefferson, 1989). Resident 

Dall’s porpoises breed in Puget Sound 

from August to September. 

Acoustics—Only short duration 

pulsed sounds have been recorded for 

Dall’s porpoises (Houck and Jefferson, 

1999); this species apparently does not 

whistle often (Richardson et al., 1995). 

Dall’s porpoises produce short duration 

(50–1,500 ms), high-frequency, narrow 

band clicks, with peak energies between 

120–160 kHz (Jefferson, 1988). There is 

no published data on the hearing 

abilities of this species. 

Harbor Porpoise 

Species Description—Harbor 

porpoises belong to the Phocoenid 

(porpoise) family and are found 

extensively along the Pacific U.S. coast. 

Harbor porpoises are small, with males 

reaching average lengths of 

approximately 5 ft (1.5 m); Females are 

slightly larger with an average length of 

5.5 ft (1.7 m). The average adult harbor 

porpoise weighs between 135–170 lb 

(61–77 kg). Harbor porpoises have a 

dark grey coloration on their backs, with 

their belly and throats white. They have 

a dark grey chin patch and intermediate 

shades of grey along their sides. 

Recent preliminary genetic analyses 

of samples ranging from Monterey, CA 

to Vancouver Island, BC indicate that 

there is small-scale subdivision within 

the U.S. portion of this range (Chivers 

et al., 2002). Although geographic 

structure exists along an almost 

continuous distribution of harbor 

porpoises from California to Alaska, 

stock boundaries are difficult to draw 

because any rigid line is generally 

arbitrary from a biological perspective. 

Nevertheless, based on genetic data and 

density discontinuities identified from 

aerial surveys, NMFS identifies eight 

stocks in the Northeast Pacific Ocean. 

Pacific coast harbor porpoise stocks 

include: (1) Monterey Bay, (2) San 

Francisco-Russian River, (3) northern 

California/southern Oregon, (4) Oregon/ 

Washington coastal, (5) inland 

Washington, (6) Southeast Alaska, (7) 

Gulf of Alaska, and (8) Bering Sea. Only 

individuals from the Washington Inland 

Waters stock may occur in the project 

area. 

Status—Aerial surveys of the inland 

waters of Washington and southern 

British Columbia were conducted 

during August of 2002 and 2003 (J. 

Laake, unpubl. data). These aerial 

surveys included the Strait of Juan de 

Fuca, San Juan Islands, Gulf Islands, 

and Strait of Georgia, which includes 

waters inhabited by the Washington 

Inland Waters stock of harbor porpoises 

as well as harbor porpoises from British 

Columbia. An average of the 2002 and 

2003 estimates of abundance in U.S. 

waters resulted in an uncorrected 

abundance of 3,123 (CV = 0.10) harbor 

porpoises in Washington inland waters 

(J. Laake, unpubl. data). When corrected 

for availability and perception bias, the 

estimated abundance for the 

Washington Inland Waters stock of 

harbor porpoise is 10,682 (CV = 0.38) 

animals (Carretta et al., 2008). The 

minimum population estimate is 7,841. 

Harbor porpoise are not listed as 

depleted under the MMPA or listed 

under the ESA. Based on currently 

available data, the total level of humancaused mortality is not known to exceed 

the PBR. Therefore, the Washington 

Inland Waters harbor porpoise stock is 

not classified as strategic. The status of 

this stock relative to its OSP level and 

population trends is unknown. 

Although long-term harbor porpoise 

sightings in southern Puget Sound have 

declined since the 1940s, sightings have 

increased in Puget Sound and northern 

Hood Canal in recent years and are now 

considered to regularly occur yearround in these waters (Calambokidis, 

2010). This may represent a return to 

historical conditions, when harbor 

porpoises were considered one of the 

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most common cetaceans in Puget Sound 

(Scheffer and Slipp, 1948). 

Distribution—Harbor porpoises are 

generally found in cool temperate to 

subarctic waters over the continental 

shelf in both the North Atlantic and 

North Pacific (Read, 1999). This species 

is seldom found in waters warmer than 

17 °C (63 °F; Read, 1999) or south of 

Point Conception (Hubbs, 1960; Barlow 

and Hanan, 1995). Harbor porpoises can 

be found year-round primarily in the 

shallow coastal waters of harbors, bays, 

and river mouths (Green et al., 1992). 

Along the Pacific coast, harbor 

porpoises occur from Monterey Bay, 

California to the Aleutian Islands and 

west to Japan (Reeves et al., 2002). 

Harbor porpoises are known to occur in 

Puget Sound year round (Osmek et al., 

1996, 1998; Carretta et al., 2007), and 

harbor porpoise observations in 

northern Hood Canal have increased in 

recent years (Calambokidis, 2010). Prior 

to recent construction projects 

conducted by the Navy at NBKB, harbor 

porpoises were considered as likely 

occurring only occasionally in the 

project area. A single harbor porpoise 

had been sighted in deeper water at 

NBKB during 2010 field observations 

(SAIC, 2010). However, while 

implementing monitoring plans for 

work conducted from July-October, 

2011, the Navy recorded multiple 

sightings of harbor porpoise in the 

deeper waters of the project area. 

Following these sightings, the Navy 

conducted dedicated line transect 

surveys, recording multiple additional 

sightings of harbor porpoise, and have 

revised local density estimates 

accordingly. The current density 

estimates are based upon a small sample 

size of transect surveys, and may be 

further revised as more information 

becomes available from ongoing Navy 

survey efforts. 

Behavior and Ecology—Harbor 

porpoises are non-social animals 

usually seen in small groups of two to 

five animals. Little is known about their 

social behavior. Harbor porpoises can be 

opportunistic foragers but primarily 

consume schooling forage fish (Osmek 

et al., 1996; Bowen and Siniff, 1999; 

Reeves et al., 2002). Along the coast of 

Washington, harbor porpoises primarily 

feed on herring, market squid (Loligo 

opalescens) and eulachon (Thaleichthys 

pacificus) (Gearin et al., 1994). Females 

reach sexual maturity at three to four 

years of age and may give birth every 

year for several years in a row. Calves 

are born in late spring (Read, 1990; Read 

and Hohn, 1995). Dall’s and harbor 

porpoises appear to hybridize relatively 

frequently in the Puget Sound area 

(Willis et al., 2004). 

Acoustics—Harbor porpoise 

vocalizations include clicks and pulses 

(Ketten, 1998), as well as whistle-like 

signals (Verboom and Kastelein, 1995). 

The dominant frequency range is 110– 

150 kHz, with source levels of 135–177 

dB re 1 mPa-m (Ketten, 1998). 

Echolocation signals include one or two 

low-frequency components in the 1.4– 

2.5 kHz range (Verboom and Kastelein, 

1995). 

A behavioral audiogram of a harbor 

porpoise indicated the range of best 

sensitivity is 8–32 kHz at levels between 

45–50 dB re 1 mPa-m (Andersen, 1970); 

however, auditory-evoked potential 

studies showed a much higher 

frequency of approximately 125–130 

kHz (Bibikov, 1992). The auditoryevoked potential method suggests that 

the harbor porpoise actually has two 

frequency ranges of best sensitivity. 

More recent psycho-acoustic studies 

found the range of best hearing to be 16– 

140 kHz, with a reduced sensitivity 

around 64 kHz (Kastelein et al., 2002). 

Maximum sensitivity occurs between 

100–140 kHz (Kastelein et al., 2002). 

Potential Effects of the Specified 

Activity on Marine Mammals 

NMFS has determined that pile 

removal, as outlined in the project 

description, has the potential to result 

in behavioral harassment of marine 

mammals that may be swimming, 

foraging, or resting in the project 

vicinity while pile removal is being 

conducted. Pile removal could 

potentially harass those pinnipeds that 

are in the water close to the project site, 

whether their heads are above or below 

the surface. 

Marine Mammal Hearing 

The primary effect on marine 

mammals anticipated from the specified 

activities would result from exposure of 

animals to underwater sound. Exposure 

to sound can affect marine mammal 

hearing. When considering the 

influence of various kinds of sound on 

the marine environment, it is necessary 

to understand that different kinds of 

marine life are sensitive to different 

frequencies of sound. Based on available 

behavioral data, audiograms derived 

using auditory evoked potential 

techniques, anatomical modeling, and 

other data, Southall et al. (2007) 

designate functional hearing groups for 

marine mammals and estimate the lower 

and upper frequencies of functional 

hearing of the groups. The functional 

groups and the associated frequencies 

are indicated below (though animals are 

less sensitive to sounds at the outer edge 

of their functional range and most 

sensitive to sounds of frequencies 

within a smaller range somewhere in 

the middle of their functional hearing 

range): 

• Low frequency cetaceans (13 

species of mysticetes): functional 

hearing is estimated to occur between 

approximately 7 Hz and 22 kHz; 

• Mid-frequency cetaceans (32 

species of dolphins, six species of larger 

toothed whales, and nineteen species of 

beaked and bottlenose whales): 

Functional hearing is estimated to occur 

between approximately 150 Hz and 160 

kHz; 

• High frequency cetaceans (six 

species of true porpoises, four species of 

river dolphins, two members of the 

genus Kogia, and four dolphin species 

of the genus Cephalorhynchus): 

Functional hearing is estimated to occur 

between approximately 200 Hz and 180 

kHz; and 

• Pinnipeds in water: Functional 

hearing is estimated to occur between 

approximately 75 Hz and 75 kHz, with 

the greatest sensitivity between 

approximately 700 Hz and 20 kHz. 

As mentioned previously in this 

document, three pinniped and four 

cetacean species are likely to occur in 

the proposed project area. Of the four 

cetacean species likely to occur in the 

project area, two are classified as high 

frequency cetaceans (Dall’s and harbor 

porpoises), one is classified as a midfrequency cetacean (killer whales), and 

one is classified as a low-frequency 

cetacean (humpback whales) (Southall 

et al., 2007). 

Underwater Sound Effects 

Potential Effects of Construction 

Sound—The effects of sounds from pile 

removal might—in theory, at least— 

result in 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., 2004; 

Nowacek et al., 2007; Southall et al., 

2007). The effects of pile driving or 

removal on marine mammals are 

generally dependent on several factors, 

including the size, type, and depth of 

the animal; the depth, intensity, and 

duration of the pile removal sound; the 

depth of the water column; the substrate 

of the habitat; the standoff distance 

between the pile and the animal; and 

the sound propagation properties of the 

environment. Impacts to marine 

mammals from the proposed activities 

are expected to result primarily from 

acoustic pathways. As such, the degree 

of effect is intrinsically related to the 

received level and duration of the sound 

exposure, which are in turn influenced 

by the distance between the animal and 

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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. Shallow 

environments are typically more 

structurally complex, which leads to 

rapid sound attenuation. 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 remove the pile, 

which would ultimately decrease the 

intensity of the acoustic source. 

In the absence of mitigation, impacts 

to marine species would be expected to 

result from physiological and behavioral 

responses to both the type and strength 

of the acoustic signature (Viada et al., 

2008). The type and severity of 

behavioral impacts are more difficult to 

define due to limited studies addressing 

the behavioral effects of underwater 

sounds on marine mammals. Potential 

effects from sound sources can range in 

severity, ranging from effects such as 

behavioral disturbance, tactile 

perception, physical discomfort, slight 

injury of the internal organs and the 

auditory system, to mortality (Yelverton 

et al., 1973; O’Keefe and Young, 1984; 

DoN, 2001b). 

Hearing Impairment and Other 

Physical Effects—Marine mammals 

exposed to high intensity sound 

repeatedly or for prolonged periods can 

experience hearing threshold shift (TS), 

which is the loss of hearing sensitivity 

at certain frequency ranges (Kastak et 

al., 1999; Schlundt et al., 2000; 

Finneran et al., 2002, 2005). TS can be 

permanent (PTS), in which case the loss 

of hearing sensitivity is not recoverable, 

or temporary (TTS), in which case the 

animal’s hearing threshold would 

recover over time (Southall et al., 2007). 

Marine mammals depend on acoustic 

cues for vital biological functions, (e.g., 

orientation, communication, finding 

prey, avoiding predators); thus, TTS 

may result in reduced fitness in survival 

and reproduction, either permanently or 

temporarily. However, this depends on 

the frequency and duration of TTS, as 

well as the biological context in which 

it occurs. TTS of limited duration, 

occurring in a frequency range that does 

not coincide with that used for 

recognition of important acoustic cues, 

would have little to no effect on an 

animal’s fitness. Repeated sound 

exposure that leads to TTS could cause 

PTS. PTS is considered to constitute 

injury, but TTS is not considered injury 

(Southall et al., 2007). It is unlikely that 

the project would result in any cases of 

temporary or especially permanent 

hearing impairment or any significant 

non-auditory physical or physiological 

effects; these effects are most frequently 

associated with pulsed sound, which 

would not occur during the proposed 

action. Some behavioral disturbance is 

expected, but it is likely that this would 

be localized and short-term because of 

the short project duration. 

In addition, given the low source 

levels expected in association with the 

non-pulsed sounds proposed for this 

activity, it is highly unlikely that any 

marine mammals could experience 

physiological effects or even TTS. All 

source levels for the proposed action 

would be less than 190 dB re: 1 mPa rms; 

therefore, there is no possibility of 

injury for pinnipeds. While vibratory 

pile removal is expected to produce 

sound equaling the 180 dB threshold for 

potential cetacean injury, that sound is 

expected to be restricted to a radius no 

more than 1 m (3.3 ft) from the pile 

removal, therefore essentially 

eliminating the possibility for cetacean 

injury, as it is extremely unlikely that 

any cetacean would approach so 

closely. Nevertheless, several aspects of 

the planned monitoring and mitigation 

measures for this project (see the 

‘‘Proposed Mitigation’’ and ‘‘Proposed 

Monitoring and Reporting’’ sections 

later in this document) are designed to 

detect marine mammals occurring near 

the pile removal to avoid exposing them 

to sound that might, in theory, cause 

injury. The following subsection 

discusses TTS in somewhat more detail. 

Temporary Threshold Shift—TTS is 

the mildest form of hearing impairment 

that can occur during exposure to a 

strong sound (Kryter, 1985). While 

experiencing TTS, the hearing threshold 

rises, and a sound must be stronger in 

order to be heard. In terrestrial 

mammals, TTS can last from minutes or 

hours to days (in cases of strong TTS). 

For sound exposures at or somewhat 

above the TTS threshold, hearing 

sensitivity in both terrestrial and marine 

mammals 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. Available data on 

TTS in marine mammals are 

summarized in Southall et al. (2007). 

Disturbance Reactions 

Disturbance includes a variety of 

effects, including subtle changes in 

behavior, more conspicuous changes in 

activities, and displacement. Reactions 

to sound, if any, depend on species, 

state of maturity, experience, current 

activity, reproductive state, time of day, 

and many other factors (Richardson et 

al., 1995; Wartzok et al., 2004; Southall 

et al., 2007; Weilgart, 2007). Behavioral 

responses to sound are highly variable 

and context specific. For each potential 

behavioral change, the magnitude of the 

change ultimately determines the 

severity of the response. A number of 

factors may influence an animal’s 

response to sound, including its 

previous experience, its auditory 

sensitivity, its biological and social 

status (including age and sex), and its 

behavioral state and activity at the time 

of exposure. 

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., 2003/04). Animals are 

most likely to habituate to sounds that 

are predictable and unvarying. 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. Behavioral state may affect 

the type of response as well. 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., 2003/04). Controlled 

experiments with captive marine 

mammals showed pronounced 

behavioral reactions, including 

avoidance of loud sound sources 

(Ridgway et al., 1997; Finneran et al., 

2003). However, responses to nonpulsed sound, such as vibratory pile 

installation, have not been documented 

as well as responses to pulsed sounds. 

With both types of pile removal, it is 

likely that the onset of pile removal 

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 inwater disturbance (Caltrans 2001, 2006). 

Since pile removal would likely only 

occur for a few hours a day, over a short 

period of time, it is unlikely to result in 

permanent displacement. Any potential 

impacts from pile removal activities 

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25424 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

could be experienced by individual 

marine mammals, but would not be 

likely to cause population level impacts, 

or affect the long-term fitness of the 

species. 

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 be 

causing beaked whale stranding due to 

exposure to military mid-frequency 

tactical sonar); 

• Habitat abandonment due to loss of 

desirable acoustic environment; and 

• 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, or 

interfering with, a marine mammal’s 

ability to hear other sounds. Masking 

occurs when the receipt of a sound is 

interfered with by another coincident 

sound at similar frequencies and at 

similar or higher levels. Chronic 

exposure to excessive, though not highintensity, sound could cause masking at 

particular frequencies for marine 

mammals that utilize sound for vital 

biological functions. Masking can 

interfere with detection of acoustic 

signals such as communication calls, 

echolocation sounds, and 

environmental sounds important to 

marine mammals. Therefore, under 

certain circumstances, marine mammals 

whose acoustical sensors or 

environment are being severely masked 

could also be impaired from maximizing 

their performance fitness in survival 

and reproduction. If the coincident 

(masking) sound were man-made, it 

could be potentially harassing if it 

disrupted hearing-related behavior. 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. Because sound generated from 

in-water pile removal is mostly 

concentrated at low frequency ranges, it 

may have less effect on high frequency 

echolocation sounds made by porpoises. 

However, lower frequency man-made 

sounds are more likely to affect 

detection of communication calls and 

other potentially important natural 

sounds such as surf and prey sound. It 

may also affect communication signals 

when they occur near the sound band 

and thus reduce the communication 

space of animals (e.g., Clark et al., 2009) 

and cause increased stress levels (e.g., 

Foote et al., 2004; Holt et al., 2009). 

Masking has the potential to impact 

species at population, community, or 

even ecosystem levels, as well as at 

individual levels. Masking affects both 

senders and receivers of the signals and 

can potentially have long-term chronic 

effects on marine mammal species and 

populations. Recent research suggests 

that 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, and that most of these increases 

are from distant shipping (Hildebrand, 

2009). All anthropogenic sound sources, 

such as those from vessel traffic, pile 

removal, and dredging activities, 

contribute to the elevated ambient 

sound levels, thus intensifying masking. 

However, the sum of sound from the 

proposed activities is confined in an 

area of inland waters (Hood Canal) that 

is bounded by landmass; therefore, the 

sound generated is not expected to 

contribute to increased ocean ambient 

sound. 

Typically, the most intense 

underwater sounds associated with 

marine construction are those produced 

by impact pile removal, which is not 

proposed for this action. However, the 

energy distribution of pile removal 

covers a broad frequency spectrum, and 

sound from these sources would likely 

be within the audible range of the 

marine mammals found in the Hood 

Canal. Vibratory pile removal is 

relatively short-term, with rapid 

oscillations occurring for approximately 

1 hour per pile, with the total vibratory 

pile removal occurring for 15 days. The 

probability for vibratory pile removal 

masking acoustic signals important to 

the behavior and survival of marine 

mammal species is likely to be 

negligible. 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 pile removal, and which 

have already been taken into account in 

the exposure analysis. 

Airborne Sound Effects 

Marine mammals that occur in the 

project area could be exposed to 

airborne sounds associated with pile 

removal that have the potential to cause 

harassment, depending on their distance 

from pile removal activities. Airborne 

pile removal sound would have less 

impact on cetaceans than pinnipeds 

because sound from atmospheric 

sources does not transmit well 

underwater (Richardson et al., 1995); 

thus, airborne sound would only be an 

issue for pinnipeds that are hauled-out 

or have their heads above water in the 

project area. 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 their 

habitat and move further from the 

source. Studies by Blackwell et al. 

(2004) and Moulton et al. (2005) 

indicate a tolerance or lack of response 

to unweighted airborne sounds as high 

as 96 dB rms. 

Anticipated Effects on Habitat 

The proposed activities at NBKB 

would not result in permanent impacts 

to habitats used directly by marine 

mammals, such as haul-out sites, but 

may have potential short-term impacts 

to food sources such as forage fish and 

salmonids. There are no rookeries or 

major haul-out sites within 10 km (6.2 

mi), foraging hotspots, or other ocean 

bottom structures of significant 

biological importance to marine 

mammals that may be present in the 

marine waters in the vicinity 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 most likely impact to marine 

mammal habitat occurs from pile 

removal effects on likely marine 

mammal prey (i.e., fish) near NBKB and 

minor impacts to the immediate 

substrate during removal of piles during 

the wharf rehabilitation project. 

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Pile Removal Effects on Potential Prey 

(Fish) 

Construction activities would produce 

non-pulsed sounds. Fish react to sounds 

which are especially strong and/or 

intermittent low-frequency sounds 

which are generally unlike the sounds 

that would be produced by the proposed 

action. Short duration, sharp sounds can 

cause overt or subtle changes in fish 

behavior and local distribution. 

Hastings and Popper (2005, 2009) 

identified several studies that suggest 

fish may relocate to avoid certain areas 

of sound energy. SPLs of 180 dB may 

cause noticeable changes in behavior 

(Chapman and Hawkins, 1969; Pearson 

et al., 1992; Skalski et al., 1992). SPLs 

of sufficient strength have been known 

to cause injury to fish and fish mortality 

(Caltrans, 2001; Longmuir and Lively, 

2001). The most likely impact to fish 

from pile removal activities at the 

project area would be temporary 

behavioral avoidance of the area. The 

duration of fish avoidance of this area 

after pile removal 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 and nature of sound 

produced for the project. Impacts could 

also result from potential impacts to fish 

eggs and larvae. 

Pile Removal Effects on Potential 

Foraging Habitat 

The area likely impacted by the 

project is relatively small compared to 

the available habitat in the Hood Canal. 

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 removal 

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 Hood Canal and 

nearby vicinity. 

Given the short daily duration of 

sound associated with individual pile 

removal events and the relatively small 

areas being affected, pile removal 

activities associated with the proposed 

action are not likely to have a 

permanent, adverse effect on any fish 

habitat, or populations of fish species. 

Therefore, pile removal is not likely to 

have a permanent, adverse effect on 

marine mammal foraging habitat at the 

project area. 

Previous Activity 

The proposed action for this IHA 

request represents the second year of a 

2-year project. NMFS issued an IHA for 

the first year of work on May 24, 2011 

(76 FR 30130). The Navy complied with 

the mitigation and monitoring required 

under the previous authorization. In 

accordance with the 2011 IHA, the Navy 

submitted a monitoring report, and the 

information contained therein was 

considered in this analysis. During the 

course of activities conducted under the 

previous authorization, the Navy did 

not exceed the take levels authorized 

under that IHA. Additional information 

regarding harbor porpoise, Steller sea 

lion, and humpback whale occurrence 

in the Hood Canal has been considered 

in this analysis. 

Proposed Mitigation 

In order to issue an incidental take 

authorization (ITA) under section 

101(a)(5)(D) of the MMPA, NMFS must, 

where applicable, 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 (where 

relevant). 

The modeling results for zones of 

influence (ZOIs; see ‘‘Estimated Take by 

Incidental Harassment’’) were used to 

develop mitigation measures for pile 

removal activities at NBKB. ZOIs are 

often used to effectively represent the 

mitigation zone that would be 

established around each pile to prevent 

Level A harassment of marine 

mammals, and also establish zones 

within which Level B harassment of 

marine mammals may occur. In addition 

to the measures described later in this 

section, the Navy would employ the 

following standard mitigation measures: 

(a) Conduct briefings between 

construction supervisors and crews, 

marine mammal monitoring team, 

acoustical monitoring team, and Navy 

staff prior to the start of all pile removal 

activity, and when new personnel join 

the work, in order to explain 

responsibilities, communication 

procedures, marine mammal monitoring 

protocol, and operational procedures. 

(b) Comply with applicable 

equipment sound standards and ensure 

that all construction equipment has 

sound control devices no less effective 

than those provided on the original 

equipment. 

(c) For in-water heavy machinery 

work other than pile removal, if a 

marine mammal comes within 10 m (33 

ft), operations shall cease and vessels 

shall reduce speed to the minimum 

level required to maintain steerage and 

safe working conditions. This type of 

work could include, for example, 

movement of the barge to the pile 

location or removal of the pile from the 

water column/substrate via a crane (i.e., 

direct pull). For these activities, 

monitoring would take place from 15 

minutes prior to initiation until the 

action is complete. 

Monitoring and Shutdown 

The following measures would apply 

to the Navy’s mitigation through 

shutdown and disturbance zones: 

Shutdown Zone—For all pile removal 

activities, the Navy would establish a 

shutdown zone (defined as, at 

minimum, the area in which SPLs equal 

or exceed the 180/190 dB rms acoustic 

injury criteria). 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, serious injury, or 

death of marine mammals. Although 

predictions indicate that radial 

distances to the 180/190-dB threshold 

would be less than 10 m—or would not 

exist because source levels are lower 

than the threshold—shutdown zones 

would conservatively be set at a 

minimum 10 m. This precautionary 

measure is intended to further reduce 

any possibility of injury to marine 

mammals by incorporating a buffer to 

the 180/190-dB threshold within the 

shutdown area. 

Disturbance Zone—For all pile 

removal activities, the Navy would 

establish a disturbance zone. 

Disturbance zones are typically defined 

as the area in which SPLs equal or 

exceed 120 dB rms (for non-pulsed 

sound). However, when the size of a 

disturbance zone is sufficiently large as 

to make monitoring of the entire area 

impracticable (as in the case of the 

vibratory removal zone here, predicted 

to encompass an area of 35.9 km2), the 

disturbance zone may be defined as 

some area that may reasonably be 

monitored. The Navy would establish 

an observation position within the 

Waterfront Restricted Area (WRA), 

maximally distant from the pile removal 

operations. The additional position 

would be able to monitor an effective 

area of at least 542 m distance 

(corresponding to the predicted radial 

distance to the 120-dB threshold for 

chipping) from the pile removal activity. 

In addition, the Navy would place a 

protected species observer (PSO) aboard 

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any vessel used outside the WRA for 

hydroacoustic monitoring, for the 

duration of any such monitoring. 

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 PSOs 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 incidents of Level B 

harassment; disturbance zone 

monitoring is discussed in greater detail 

later (see Proposed Monitoring and 

Reporting). As with any such large 

action area, it is impossible to guarantee 

that all animals would be observed or to 

make comprehensive observations of 

fine-scale behavioral reactions to sound. 

All disturbance and shutdown zones 

would initially be based on the 

distances from the source that are 

predicted for each threshold level. 

However, should data from previously 

conducted acoustic monitoring (i.e., 

from monitoring of test pile or previous 

EHW–1 work), which is still in 

preparation, or from in-situ acoustic 

monitoring indicate that actual 

distances to these threshold zones are 

different, the size of the shutdown and 

disturbance zones would be adjusted 

accordingly. 

Monitoring Protocols—Monitoring 

would be conducted for a minimum 

10 m shutdown zone and a minimum 

approximate 600 m disturbance zone 

(although this may be larger for the 

duration of hydroacoustic monitoring) 

surrounding each pile for the presence 

of marine mammals before, during, and 

after pile removal activities. If a marine 

mammal is observed within the 

disturbance zone, a take would be 

recorded and behaviors documented. 

However, that pile segment would be 

completed without cessation, unless the 

animal approaches or enters the 

shutdown zone, at which point all pile 

removal activities would be halted. 

The disturbance zone was set at the 

largest area practicable for the Navy to 

maintain a monitoring presence over the 

duration of the activity. Sightings 

occurring outside this area (within the 

predicted 35.9 km2 disturbance zone 

predicted for the vibratory removal 120- 

dB isopleths) would still be recorded 

and noted as a take, but detailed 

observations outside this zone would 

not be possible, and it would be 

impossible for the Navy to account for 

all individuals occurring in such a zone 

with any degree of certainty. Monitoring 

would take place from 15 minutes prior 

to initiation through 30 minutes postcompletion of pile removal activities. 

Pile removal activities include the time 

to remove a single pile or series of piles, 

as long as the time elapsed between uses 

of the pile removal equipment is no 

more than 30 minutes. 

The following additional measures 

would apply to visual monitoring: 

(a) Monitoring would be conducted by 

qualified observers. Qualified observers 

are 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; 

• Advanced education in biological 

science, wildlife management, 

mammalogy, or related fields (bachelor’s 

degree or higher is required); 

• 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. 

A trained observer would be placed 

from the best vantage point(s) 

practicable (e.g., from a small boat, the 

pile removal barge, on shore, or any 

other suitable location) to monitor for 

marine mammals and implement 

shutdown or delay procedures when 

applicable by calling for the shutdown 

to the equipment operator. 

(b) Prior to the start of pile removal 

activity, the shutdown zone would be 

monitored for 15 minutes to ensure that 

it is clear of marine mammals. Pile 

removal would only commence once 

observers have declared the shutdown 

zone clear of marine mammals; animals 

would be allowed to remain in the 

disturbance zone (i.e., must leave of 

their own volition) and their behavior 

would be monitored and documented. 

(c) If a marine mammal approaches or 

enters the shutdown zone during the 

course of pile removal operations, pile 

removal would be halted and delayed 

until either the animal has voluntarily 

left and been visually confirmed beyond 

the shutdown zone or 15 minutes have 

passed without re-detection of the 

animal. 

Acoustic Measurements 

Acoustic measurements would be 

used to empirically verify the predicted 

shutdown and disturbance zones for 

pneumatic chipping. For further detail 

regarding the Navy’s acoustic 

monitoring plan see ‘‘Proposed 

Monitoring and Reporting’’. 

Timing Restrictions 

The Navy has set timing restrictions 

for pile removal activities to avoid inwater work when ESA-listed fish 

populations are most likely to be 

present. The in-water work window for 

avoiding negative impacts to fish 

species is July 16–February 15. 

Soft Start 

The use of a soft-start procedure is 

believed to provide additional 

protection to marine mammals by 

warning, or providing marine mammals 

a chance to leave the area prior to the 

hammer operating at full capacity. The 

wharf rehabilitation project would 

utilize soft-start techniques for vibratory 

pile removal. The soft-start requires 

contractors to initiate sound from 

vibratory hammers for fifteen seconds at 

reduced energy followed by a 30-second 

waiting period. This procedure would 

be repeated two additional times. 

Daylight Construction 

Pile removal and other in-water work 

would occur only during daylight hours 

(i.e., civil dawn to civil dusk). 

Mitigation Effectiveness 

It should be recognized that although 

marine mammals would be protected 

through the use of measures described 

here, the efficacy of visual detection 

depends on several factors including the 

observer’s ability to detect the animal, 

the environmental conditions (visibility 

and sea state), and monitoring 

platforms. All observers utilized for 

mitigation activities would be 

experienced biologists with training in 

marine mammal detection and behavior. 

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Trained observers have specific 

knowledge of marine mammal 

physiology, behavior, and life history, 

which may improve their ability to 

detect individuals or help determine if 

observed animals are exhibiting 

behavioral reactions to construction 

activities. 

The Puget Sound region, including 

the Hood Canal, only infrequently 

experiences winds with velocities in 

excess of 25 kn (Morris et al., 2008). The 

typically light winds afforded by the 

surrounding highlands coupled with the 

fetch-limited environment of the Hood 

Canal result in relatively calm wind and 

sea conditions throughout most of the 

year. The wharf rehabilitation project 

site has a maximum fetch of 8.4 mi (13.5 

km) to the north, and 4.2 mi (6.8 km) to 

the south, resulting in maximum wave 

heights of from 2.85–5.1 ft (0.9–1.6 m) 

(Beaufort Sea State (BSS) between two 

and four), even in extreme conditions 

(30 kt winds) (CERC, 1984). Visual 

detection conditions are considered 

optimal in BSS conditions of three or 

less, which align with the conditions 

that should be expected for the wharf 

rehabilitation project at NBKB. 

NMFS has carefully evaluated the 

applicant’s proposed mitigation 

measures and considered a range of 

other measures in the context of 

ensuring that NMFS prescribes the 

means of effecting 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, including 

consideration of personnel safety, and 

practicality of implementation. 

Based on our evaluation of the 

applicant’s proposed measures, as well 

as other measures considered by NMFS, 

NMFS has 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 ITA for an 

activity, section 101(a)(5)(D) of the 

MMPA states that NMFS must, where 

applicable, 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 

ITAs must include the suggested means 

of accomplishing the necessary 

monitoring and reporting that would 

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. 

Acoustic Monitoring 

The Navy would conduct acoustic 

monitoring for pneumatic chipping of 

concrete piles to determine the actual 

distances to the 120 dB re 1 mPa rms 

isopleths for behavioral harassment 

relative to background levels. 

Underwater sound levels were 

measured at the project site in 2011 in 

the absence of construction activities to 

determine background sound levels and, 

therefore, will not be recorded again 

during this work window. Airborne 

acoustic monitoring would be 

conducted during pile removal through 

chipping to identify the actual distance 

to the 90 dB re 20 mPa rms and 100 dB 

re 20 mPa rms airborne isopleths. 

At a minimum, the methodology 

would include: 

• Acoustic monitoring will be 

conducted on a minimum of five 

concrete piles. 

• For underwater recordings, a 

stationary hydrophone system with the 

ability to measure SPLs will be placed 

in accordance with NMFS’ most recent 

guidance for collection of source levels. 

• For airborne recordings, reference 

recordings will be attempted at 

approximately 50 ft (15.2 meters) from 

the source via a stationary hydrophone. 

However, other distances may be 

utilized to obtain better data if the signal 

cannot be isolated clearly due to other 

sound sources (i.e., barges or 

generators). 

• Each hydrophone (underwater) and 

microphone (airborne) will be calibrated 

prior to the start of the action and will 

be checked at the beginning of each day 

of monitoring activity. Other 

hydrophones will be placed at other 

distances and/or depths as necessary to 

determine the distance to the thresholds 

for marine mammals. 

• Environmental data will be 

collected including but not limited to: 

Wind speed and direction, wave height, 

water depth, precipitation, and type and 

location of in-water construction 

activities, as well as other factors that 

could contribute to influencing the 

airborne and underwater sound levels 

(e.g. aircraft, boats); 

• The construction contractor will 

supply the Navy and other relevant 

monitoring personnel with the substrate 

composition, hammer model and size, 

hammer energy settings and any 

changes to those settings during the 

piles being monitored. 

• For acoustically monitored piles, 

post-analysis of the sound level signals 

will include the average, minimum, and 

maximum rms value for each pile 

monitored during removal. A frequency 

spectrum will also be provided for the 

pneumatic chipping signal. 

• Airborne levels would be recorded 

as an unweighted time series. The 

distance to marine mammal airborne 

sound disturbance thresholds would be 

determined. 

Visual Monitoring 

The Navy would 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 would be trained in marine 

mammal identification and behaviors. 

NMFS requires that the observers have 

no other construction-related tasks 

while conducting monitoring. 

Methods of Monitoring—The Navy 

would monitor the shutdown zone and 

disturbance zone before, during, and 

after pile removal. There would, at all 

times, be at least one observer stationed 

at an appropriate vantage point to 

observe the shutdown zones associated 

with each operating hammer. There 

would also at all times be at least one 

vessel-based observer stationed within 

the WRA. In addition, at least one 

marine mammal observer would be 

stationed on any vessel conducting 

acoustic monitoring outside the WRA, 

for as long as such monitoring is 

conducted. Based on NMFS 

requirements, the Marine Mammal 

Monitoring Plan would include the 

following procedures for pile removal: 

(1) 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. This may require the use of a 

small boat to monitor certain areas 

while also monitoring from one or more 

land based vantage points. 

(2) During all observation periods, 

observers would use binoculars and the 

naked eye to search continuously for 

marine mammals. 

(3) If the shutdown or disturbance 

zones are obscured by fog or poor 

lighting conditions, pile removal at that 

location would not be initiated until 

that zone is visible. 

(4) The shutdown and disturbance 

zones around the pile would be 

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monitored for the presence of marine 

mammals before, during, and after any 

pile removal activity. 

Pre-Activity Monitoring—The 

shutdown and disturbance zones would 

be monitored for 15 minutes prior to 

initiating pile removal. If marine 

mammal(s) are present within the 

shutdown zone prior to pile removal, or 

during the soft start, the start of pile 

removal would be delayed until the 

animal(s) leave the shutdown zone. Pile 

removal would resume only after the 

PSO has determined, through 

observation or by waiting 15 minutes, 

that the animal(s) has moved outside the 

shutdown zone. 

During Activity Monitoring—The 

shutdown and disturbance zones would 

also be monitored throughout the time 

required to remove a pile. If a marine 

mammal is observed entering the 

disturbance zone, a take would be 

recorded and behaviors documented. 

However, that pile segment would be 

completed without cessation, unless the 

animal enters or approaches the 

shutdown zone, at which point all pile 

removal activities would be halted. Pile 

removal can only resume once the 

animal has left the shutdown zone of its 

own volition or has not been resighted 

for a period of 15 minutes. 

Post-Activity Monitoring—Monitoring 

of the shutdown and disturbance zones 

would continue for 30 minutes 

following the completion of pile 

removal. 

Individuals implementing the 

monitoring protocol would assess its 

effectiveness using an adaptive 

approach. Monitoring biologists would 

use their best professional judgment 

throughout implementation and would 

seek improvements to these methods 

when deemed appropriate. Any 

modifications to protocol would be 

coordinated between the Navy and 

NMFS. 

Data Collection 

NMFS requires that the PSOs use 

NMFS-approved sighting forms. In 

addition to the following requirements, 

the Navy would note in their behavioral 

observations whether an animal remains 

in the project area following a Level B 

taking (which would not require 

cessation of activity). This information 

would ideally make it possible to 

determine whether individuals are 

taken (within the same day) by one or 

more types of pile removal. NMFS 

requires that, at a minimum, the 

following information be collected on 

the sighting forms: 

(1) Date and time that pile removal 

begins or ends; 

(2) Construction activities occurring 

during each observation period; 

(3) Weather parameters identified in 

the acoustic monitoring (e.g., percent 

cover, visibility); 

(4) Water conditions (e.g., sea state, 

tide state); 

(5) Species, numbers, and, if possible, 

sex and age class of marine mammals; 

(6) Marine mammal behavior patterns 

observed, including bearing and 

direction of travel, and if possible, the 

correlation to SPLs; 

(7) Distance from pile removal 

activities to marine mammals and 

distance from the marine mammals to 

the observation point; 

(8) Locations of all marine mammal 

observations; and 

(9) Other human activity in the area. 

Reporting 

A draft acoustic monitoring report 

would be submitted to NMFS within 90 

calendar days of the completion of the 

acoustic measurements. Separately, a 

draft marine mammal monitoring report 

would be submitted within 90 calendar 

days of the completion of construction 

activity. The report would include 

marine mammal observations preactivity, during-activity, and postactivity during pile removal days. Final 

reports would be prepared and 

submitted to NMFS within 30 days 

following receipt of comments on the 

draft report from NMFS. At a minimum, 

the reports would include: 

• Date and time of activity; 

• Water and weather conditions (e.g., 

sea state, tide state, percent cover, 

visibility); 

• Description of the pile removal 

activity (e.g., size and type of piles, 

machinery used); 

• The vibratory hammer force or 

chipping hammer setting used to extract 

the piles; 

• A description of the monitoring 

equipment; 

• The distance between 

hydrophone(s) and pile; 

• The depth of the hydrophone(s); 

• The physical characteristics of the 

bottom substrate from which the pile 

was extracted (if possible); 

• The rms range and mean for each 

monitored pile; 

• The results of the acoustic 

measurements, including the frequency 

spectrum, peak and rms SPLs for each 

monitored pile; 

• The results of the airborne sound 

measurements (unweighted levels); 

• Date and time observation is 

initiated and terminated; 

• A description of any observable 

marine mammal behavior in the 

immediate area and, if possible, the 

correlation to underwater sound levels 

occurring at that time; 

• Actions performed to minimize 

impacts to marine mammals; 

• Times when pile removal is 

stopped due to presence of marine 

mammals within shutdown zones and 

time when pile removal resumes; 

• Results, including the detectability 

of marine mammals, species and 

numbers observed, sighting rates and 

distances, behavioral reactions within 

and outside of shutdown zones; and 

• A refined take estimate based on the 

number of marine mammals observed in 

the shutdown and disturbance zones. 

Estimated Take by Incidental 

Harassment 

With respect to the activities 

described here, the MMPA defines 

‘‘harassment’’ as: ‘‘any act of pursuit, 

torment, or annoyance which (i) has the 

potential to injure a marine mammal or 

marine mammal stock in the wild [Level 

A harassment]; or (ii) has the potential 

to disturb a marine mammal or marine 

mammal stock in the wild by causing 

disruption of behavioral patterns, 

including, but not limited to, migration, 

breathing, nursing, breeding, feeding, or 

sheltering [Level B harassment].’’ 

All anticipated takes would be by 

Level B harassment, 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 

remote. However, it is unlikely that 

injurious or lethal takes would occur 

even in the absence of the planned 

mitigation and monitoring measures. 

If a marine mammal responds to an 

underwater sound 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 or 

on the stock or species could potentially 

be significant (Lusseau and Bejder, 

2007; Weilgart, 2007). 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. This 

practice potentially overestimates the 

numbers of marine mammals taken. For 

example, during the past 10 years, killer 

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whales have been observed within the 

project area twice. On the basis of that 

information, an estimated amount of 

potential takes for killer whales is 

presented here. However, while a pod of 

killer whales could potentially visit 

again during the project timeframe, and 

thus be taken, it is more likely that they 

would not. 

The proposed project area is not 

believed to be particularly important 

habitat for marine mammals, although 

harbor seals are year-round residents of 

Hood Canal and sea lions are known to 

haul-out on submarines and other manmade objects at the NBKB waterfront 

(although typically at a distance of a 

mile or greater from the project site). 

Therefore, behavioral disturbances that 

could result from anthropogenic sound 

associated with the proposed activities 

are expected to affect only a relatively 

small number of individual marine 

mammals, although those effects could 

be recurring if the same individuals 

remain in the project vicinity. 

The Navy is requesting authorization 

for the potential taking of small 

numbers of Steller sea lions, California 

sea lions, harbor seals, transient killer 

whales, Dall’s porpoises, and harbor 

porpoises in the Hood Canal that may 

result from pile removal during 

construction activities associated with 

the wharf rehabilitation project 

described previously in this document. 

No incidental take of humpback whale 

is predicted. The takes requested are 

expected to have no more than a minor 

effect on individual animals and no 

effect at the population level for these 

species. Any effects experienced by 

individual marine mammals are 

anticipated to be limited to short-term 

disturbance of normal behavior or 

temporary displacement of animals near 

the source of the sound. 

Marine Mammal Densities 

For all species, the best scientific 

information available was used to 

construct density estimates or estimate 

local abundance. Of available 

information deemed suitable for use, the 

data that produced the most 

conservative (i.e., highest) density or 

abundance estimate for each species 

was used. For harbor seals, this 

involved published literature describing 

harbor seal research conducted in 

Washington and Oregon as well as more 

specific counts conducted in Hood 

Canal (Huber et al., 2001; Jeffries et al., 

2003). Killer whales are known from 

two periods of occurrence (2003 and 

2005) and are not known to 

preferentially use any specific portion of 

the Hood Canal. Therefore, density was 

calculated as the maximum number of 

individuals present at a given time 

during those occurrences (London, 

2006), divided by the area of Hood 

Canal. The best information available 

for the remaining species in Hood Canal 

came from surveys conducted by the 

Navy at the NBKB waterfront or in the 

vicinity of the project area. These 

consist of three discrete sets of survey 

effort, and are described here in greater 

detail. 

Beginning in April 2008, Navy 

personnel have recorded sightings of 

marine mammals occurring at known 

haul-outs along the NBKB waterfront, 

including docked submarines or other 

structures associated with NBKB docks 

and piers and the nearshore pontoons of 

the floating security fence. Sightings of 

marine mammals within the waters 

adjoining these locations were also 

recorded. Sightings were attempted 

whenever possible during a typical 

work week (i.e., Monday through 

Friday), but inclement weather, 

holidays, or security constraints often 

precluded surveys. These sightings took 

place frequently (average fourteen per 

month) although without a formal 

survey protocol. During the surveys, 

staff visited each of the abovementioned locations and recorded 

observations of marine mammals. 

Surveys were conducted using 

binoculars and the naked eye from 

shoreline locations or the piers/wharves 

themselves. Because these surveys 

consist of opportunistic sighting data 

from shore-based observers, largely of 

hauled-out animals, there is no 

associated survey area appropriate for 

use in calculating a density from the 

abundance data. Thus, NMFS has not 

used these data to derive a density but 

rather has used the absolute abundance 

to estimate take. For analysis in this 

proposed IHA, data were compiled for 

the period from April 2008 through June 

2010—with the additional inclusion of 

twelve surveys from October 2011 in 

which only Steller sea lion observations 

were recorded, as this was the first 

record of Steller sea lion presence 

during the month of October—and these 

data provided the basis for take 

estimation for Steller and California sea 

lions. Other information, including 

sightings data from other Navy survey 

efforts at NBKB, is available for these 

two species, but these data provide the 

most conservative (i.e., highest) local 

abundance estimates (and thus the 

highest estimates of potential take). For 

all other species, the data source that 

provided the most conservative density 

estimate was used. 

Vessel-based marine wildlife surveys 

were conducted according to 

established survey protocols during July 

through September 2008 and November 

through May 2009–10 (Tannenbaum et 

al., 2009, 2011). Eighteen complete 

surveys of the nearshore area resulted in 

observations of four marine mammal 

species (harbor seal, California sea lion, 

harbor porpoise, and Dall’s porpoise). 

These surveys operated along predetermined transects parallel to the 

shoreline from the nearshore out to 

approximately 1,800 ft (549 m) from 

shoreline, at a spacing of 100 yd (91 m), 

and covered the entire NBKB waterfront 

(approximately 3.9 km2 per survey) at a 

speed of 5 kn or less. Two observers 

recorded sightings of marine mammals 

both in the water and hauled out, 

including date, time, species, number of 

individuals, age (juvenile, adult), 

behavior (swimming, diving, hauled 

out, avoidance dive), and haul-out 

location. Positions of marine mammals 

were obtained by recording distance and 

bearing to the animal with a rangefinder 

and compass, noting the concurrent 

location of the boat with GPS, and, 

subsequently, analyzing these data to 

produce coordinates of the locations of 

all animals detected. These surveys 

produced the information used to 

estimate take for Dall’s porpoise. 

During 2011 construction activities, 

marine mammal monitoring was 

conducted on construction days for 

mitigation purposes. During those 

efforts, the Navy observed that harbor 

porpoises were more common in deeper 

waters of Hood Canal than the 

previously described, nearshore vesselbased surveys indicated. For that 

reason, the Navy conducted vesselbased line transect surveys in Hood 

Canal on days when no construction 

activities occurred in order to collect 

additional density data for species 

present in Hood Canal. These surveys 

were primarily conducted in September 

and detected three marine mammal 

species (harbor seal, California sea lion, 

and harbor porpoise), and included 

surveys conducted in both the main 

body of Hood Canal, near the project 

area, and baseline surveys conducted for 

comparison in Dabob Bay, an area of 

Hood Canal that is not affected by sound 

from Navy actions at the NBKB 

waterfront (see Figures 2–1 and 4–1 in 

the Navy’s application). The surveys 

operated along pre-determined transects 

that followed a double saw-tooth pattern 

to achieve uniform coverage of the 

entire NBKB waterfront. The vessel 

traveled at a speed of approximately 

5 kn when transiting along the transect 

lines. Two observers recorded sightings 

of marine mammals both in the water 

and hauled out, including the date, 

time, species, number of individuals, 

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and behavior (swimming, diving, etc.). 

Positions of marine mammals were 

obtained by recording the distance and 

bearing to the animal(s), noting the 

concurrent location of the boat with 

GPS, and subsequently analyzing these 

data to produce coordinates of the 

locations of all animals detected. 

Sighting information for harbor 

porpoises was corrected for detectability 

(g(0) = 0.54; Barlow, 1988; Calambokidis 

et al., 1993; Carretta et al., 2001). 

Distance sampling methodologies were 

used to estimate densities of animals for 

these data. Due to the recent execution 

of these surveys, not all data have been 

processed. Due to the unexpected 

abundance of harbor porpoises 

encountered, data for this species were 

processed first and are available for use 

in this proposed IHA. All other species 

data may be included in subsequent 

environmental compliance documents 

once all post-processing is complete, but 

preliminary analysis indicates that use 

of the previously described data would 

still provide the most conservative take 

estimates for the other species. 

The cetaceans, as well as the harbor 

seal, appear to range throughout Hood 

Canal; therefore, the analysis in this 

proposed IHA assumes that harbor seal, 

humpback whale, transient killer whale, 

harbor porpoise, and Dall’s porpoise are 

uniformly distributed in the project 

area. However, it should be noted that 

there have been no observations of 

cetaceans within the WRA security 

barrier; the barrier thus appears to 

effectively prevent cetaceans from 

approaching the shutdown zones 

(please see Figure 6–2 of the Navy’s 

application; the WRA security barrier, 

which is not denoted in the figure 

legend, is represented by a thin gray 

line). Although source levels associated 

with the proposed actions are so low 

that no Level A harassments would 

likely occur even in the absence of any 

mitigation measures, it appears that 

cetaceans at least are not at risk of Level 

A harassment at NBKB even from louder 

activities (e.g., impact pile driving). The 

remaining species that occur in the 

project area, Steller sea lion and 

California sea lion, do not appear to 

utilize most of Hood Canal. The sea 

lions appear to be attracted to the manmade haul-out opportunities along the 

NBKB waterfront while dispersing for 

foraging opportunities elsewhere in 

Hood Canal. California sea lions were 

not reported during aerial surveys of 

Hood Canal (Jeffries et al., 2000), and 

Steller sea lions have only been 

documented at the NBKB waterfront. 

Description of Take Calculation 

The take calculations presented here 

rely on the best data currently available 

for marine mammal populations in the 

Hood Canal, as discussed in preceding 

sections. The formula was developed for 

calculating take due to pile removal 

activity and applied to each groupspecific sound impact threshold. The 

formula is founded on the following 

assumptions: 

• All pilings to be installed would 

have a sound disturbance distance equal 

to that of the piling that causes the 

greatest sound disturbance (i.e., the 

piling furthest from shore); 

• All marine mammal individuals 

potentially available are assumed to be 

present within the relevant area, and 

thus incidentally taken; and, 

• An individual can only be taken 

once during a 24-hour period. 

The calculation for marine mammal 

takes is estimated by: 

Take estimate = (n * ZOI) * days of 

total activity 

Where: 

n = density estimate used for each species/ 

season 

ZOI = sound threshold zone of influence 

(ZOI) impact area; the area encompassed 

by all locations where the SPLs equal or 

exceed the threshold being evaluated 

n * ZOI produces an estimate of the 

abundance of animals that could be 

present in the area for exposure, and is 

rounded to the nearest whole number 

before multiplying by days of total 

activity. 

The ZOI impact area is the estimated 

range of impact to the sound criteria. 

The distances specified in Tables 2 and 

4 (actual distances rather than modeled) 

were used to calculate ZOI around each 

pile. The ZOI impact area took into 

consideration the possible affected area 

of the Hood Canal from the pile removal 

site furthest from shore with attenuation 

due to land shadowing from bends in 

the canal. Because of the close 

proximity of some of the piles to the 

shore, the narrowness of the canal at the 

project area, and the maximum fetch, 

the ZOIs for each threshold are not 

necessarily spherical and may be 

truncated. 

For sea lions, as described previously, 

the surveys offering the most 

conservative estimates of abundance do 

not have a defined survey area and so 

are not suitable for deriving a density 

construct. Instead, abundance is 

estimated on the basis of previously 

described opportunistic sighting 

information at the NBKB waterfront, 

and it is assumed that the total amount 

of animals known from NBKB haul-outs 

would be ‘‘available’’ to be taken in a 

given pile removal day. Thus, for these 

two species, take is estimated by 

multiplying abundance by days of 

activity. 

The total number of days spent 

removing piles is expected to be a 

maximum of 15 for vibratory removal 

and 32 for chipping. While pile removal 

can occur any day throughout the inwater work window, and the analysis is 

conducted on a per day basis, only a 

fraction of that time is actually spent in 

pile removal. For each pile, vibratory 

pile removal is expected to be no more 

than 1 hour. Pneumatic chipping is 

expected to take approximately 2 hours 

per pile. 

The exposure assessment 

methodology is an estimate of the 

numbers of individuals exposed to the 

effects of pile removal activities 

exceeding NMFS-established 

thresholds. Of note in these exposure 

estimates, mitigation methods (i.e., 

visual monitoring and the use of 

shutdown zones) were not quantified 

within the assessment and successful 

implementation of this mitigation is not 

reflected in exposure estimates. Results 

from acoustic impact exposure 

assessments should be regarded as 

conservative estimates. 

Airborne Sound—No incidents of 

incidental take are predicted as a result 

of exposure to airborne sound, using the 

formula given in this section and the 

information from Table 4. This is 

primarily due to the low source levels 

associated with the specified activities. 

However, it is NMFS’ view that 

authorization for incidental take 

resulting from exposure to airborne 

sound, in the absence of any haul-outs 

or opportunities for an animal to haul 

out within the ZOI, would effectively 

result in double counting. Such 

exposure results when pinnipeds raise 

their heads above water; thus, those 

individuals are within the larger ZOI 

corresponding to Level B harassment 

resulting from underwater sound 

produced by the same source, and are 

already exposed and considered as an 

incidental take. As noted previously, 

NMFS considers an individual as able to 

be incidentally taken once per 24-hour 

period. Multiple incidents 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. 

California Sea Lion 

California sea lions are present in 

Hood Canal during much of the year 

with the exception of mid-June through 

August. California sea lions occur 

regularly in the vicinity of the project 

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site from September through mid-June, 

as determined by Navy waterfront 

surveys conducted from April 2008 

through June 2010 (Navy, 2010; Table 

6). With regard to the range of this 

species in Hood Canal and the project 

area, it is assumed on the basis of 

waterfront observations (Agness and 

Tannenbaum, 2009; Tannenbaum et al., 

2009, 2011) that the opportunity to haul 

out on submarines docked at Delta Pier 

is a primary attractant for California sea 

lions in Hood Canal, as they have rarely 

been reported, either hauled out or 

swimming, elsewhere in Hood Canal 

(Jeffries, 2007). Abundance is calculated 

as the monthly average of the maximum 

number observed in a given month, as 

opposed to the overall average (Table 6). 

For example, in the month of May, the 

maximum number of animals observed 

on any one day was 25 in 2008, 33 in 

2009, and 17 in 2010, providing a 

monthly average of the maximum daily 

number observed of 25. This provides a 

conservative overall daily abundance of 

26.2 for the in-water work window, as 

compared with an actual per survey 

abundance of 11.4 during the same 

period. 

TABLE 6—CALIFORNIA SEA LION SIGHTING INFORMATION FROM NBKB, APRIL 2008–JUNE 2010 

Month Number of 

surveys 

Number of 

surveys with 

animals present 

Frequency of 

presence 1 Abundance 2

January ............................................................................................ 25 15 0.60 24.0 

February ........................................................................................... 28 24 0.86 31.0 

March ............................................................................................... 28 26 0.93 38.5 

April .................................................................................................. 38 27 0.71 36.3 

May .................................................................................................. 44 34 0.77 25.0 

June ................................................................................................. 44 7 0.16 5.3 

July ................................................................................................... 31 0 0 0 

August .............................................................................................. 29 1 0.03 0.5 

September ....................................................................................... 26 9 0.35 22.0 

October ............................................................................................ 26 22 0.85 45.5 

November ........................................................................................ 22 22 1 54.0 

December ........................................................................................ 24 14 0.58 32.5 

Total or average (in-water work season only) .......................... 211 107 0.53 26.2 

Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July–February) only. Information 

from March–June presented for reference. 1Frequency is the number of surveys with California sea lions present/number of surveys conducted. 

2Abundance is calculated as the monthly average of the maximum daily number observed in a given month. 

The largest observed number of 

California sea lions hauled out along the 

NBKB waterfront was 58 in a November 

survey. During the in-water construction 

period (mid-July to mid-February) the 

largest daily attendance average for each 

month ranged from 24 individuals to 54 

individuals. The likelihood of California 

sea lions being present at NBKB is 

greatest from October through May, 

when the frequency of attendance in 

surveys was at least 0.58. Attendance 

along the NBKB waterfront in November 

surveys (2008–09) was 100 percent. 

Additionally, five navigational buoys 

near the entrance to Hood Canal were 

documented as potential haul-outs, each 

capable of supporting three adult 

California sea lions (Jeffries et al., 2000). 

Breeding rookeries are in California; 

therefore, pups are not expected to be 

present in Hood Canal (NMFS 2008b). 

Female California sea lions are rarely 

observed north of the California/Oregon 

border; therefore, only adult and subadult males are expected to be exposed 

to project impacts. 

The ZOI for vibratory removal 

encompasses areas where California sea 

lions are known to haul-out; assuming 

that 26 individuals could be taken per 

day of vibratory removal provides an 

estimate of 390 takes for that activity. 

The ZOI for pneumatic chipping does 

not encompass areas where California 

sea lions are known to occur; 

nevertheless, it is likely that some 

individuals would transit this area in 

route to haul out or forage. Therefore, 

and in order to ensure that the Navy is 

adequately authorized for incidental 

take, NMFS predicts that at least one 

individual California sea lion could be 

exposed to sound levels indicating 

Level B harassment per day of 

pneumatic chipping. Table 8 depicts the 

estimated number of behavioral 

harassments. 

Steller Sea Lion 

Steller sea lions were first 

documented at the NBKB waterfront in 

November 2008, while hauled out on 

submarines at Delta Pier (Bhuthimethee, 

2008; Navy, 2010) and have been 

periodically observed since that time. 

Steller sea lions typically occur at NBKB 

from November through April; however, 

the first October sightings of Steller sea 

lions at NBKB occurred in 2011. Based 

on waterfront observations, Steller sea 

lions appear to use available haul-outs 

(typically in the vicinity of Delta Pier, 

approximately one mile south of the 

project area) and habitat similarly to 

California sea lions, although in lesser 

numbers. On occasions when Steller sea 

lions are observed, they typically occur 

in mixed groups with California sea 

lions also present, allowing observers to 

confirm their identifications based on 

discrepancies in size and other physical 

characteristics. During October 2011, up 

to four individuals were sighted either 

hauled out at the submarines docked at 

Delta Pier or swimming in the waters 

just adjacent to those haul-outs. 

Vessel-based survey effort in NBKB 

nearshore waters have not detected any 

Steller sea lions (Agness and 

Tannenbaum, 2009; Tannenbaum et al., 

2009, 2011). Opportunistic sightings 

data provided by Navy personnel since 

April 2008 have continued to document 

sightings of Steller sea lions at Delta 

Pier from November through April 

(Table 7). Steller sea lions have only 

been observed hauled out on 

submarines docked at Delta Pier. Delta 

Pier and other docks at NBKB are not 

accessible to pinnipeds due to the 

height above water, although the smaller 

California sea lions and harbor seals are 

able to haul out on pontoons that 

support the floating security barrier. 

One to two animals are typically seen 

hauled out with California sea lions; the 

maximum Steller sea lion group size 

seen at any given time was six 

individuals in November 2009. 

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TABLE 9—STELLER SEA LION SIGHTING INFORMATION FROM NBKB, APRIL 2008–JUNE 2010; OCTOBER 2011 

Month Number of 

surveys 

Number of 

surveys with 

animals present 

Frequency of 

presence 1 Abundance 2

January ............................................................................................ 25 4 0.16 1.0 

February ........................................................................................... 28 1 0.04 0.5 

March ............................................................................................... 28 4 0.14 1.0 

April .................................................................................................. 38 5 0.13 1.3 

May .................................................................................................. 44 0 0 0 

June ................................................................................................. 44 0 0 0 

July ................................................................................................... 31 0 0 0 

August .............................................................................................. 29 0 0 0 

September ....................................................................................... 26 0 0 0 

October ............................................................................................ 38 12 0.32 1.3 

November ........................................................................................ 22 3 0.14 5.0 

December ........................................................................................ 24 5 0.21 1.5 

Total or average .......................................................................

(in-water work season only) ..................................................... 223 25 0.11 1.2 

Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July–February) only. Information 

from March–June presented for reference. 1 Frequency is the number of surveys with Steller sea lions present/number of surveys conducted. 2 Abundance is calculated as the monthly average of the maximum daily number observed in a given month. 

Their frequency of occurrence by 

month typically has not exceeded 0.21 

(in December 2009), i.e., they were 

present in only 21 percent of surveys 

that month. However, all 12 surveys 

conducted in October 2011 resulted in 

Steller sea lion sightings, raising the 

frequency of occurrence for that month 

to 0.32. The time period from November 

through April coincides with the time 

when Steller sea lions are frequently 

observed in Puget Sound. Only adult 

and sub-adult males are likely to be 

present in the project area during this 

time; female Steller sea lions have not 

been observed in the project area. Since 

there are no known breeding rookeries 

in the vicinity of the project site, Steller 

sea lion pups are not expected to be 

present. By May, most Steller sea lions 

have left inland waters and returned to 

their rookeries to mate. Although subadult individuals (immature or prebreeding animals) will occasionally 

remain in Puget Sound over the 

summer, observational data (Table 7) 

have indicated that Steller sea lions are 

present only from October through April 

and not during the summer months. 

Local abundance information, rather 

than density, was used in estimating 

take for Steller sea lions. Please see the 

discussion provided previously for 

California sea lions. Steller sea lions are 

known only from haul-outs over one 

mile from the project area, and would 

not be subject to harassment from 

airborne sound. The ZOI for vibratory 

removal encompasses areas where 

Steller sea lions are known to haul-out; 

assuming that one individual could be 

taken per day of vibratory removal 

provides an estimate of fifteen takes for 

that activity. However, the available 

abundance information does not reflect 

the nature of Steller sea lion occurrence 

at NBKB. According to the most recent 

observational information, if Steller sea 

lions are present at NBKB, it is possible 

that as many as four individuals could 

be present on submarines docked at 

Delta Pier or in waters adjacent to these 

haul-outs. Thus, NMFS conservatively 

assumes that up to four individuals 

could be exposed to sound levels 

indicating Level B harassment per day 

of vibratory pile removal. Similar to 

California sea lions, the ZOI for 

pneumatic chipping does not 

encompass areas where Steller sea lions 

are known to occur; nevertheless, it is 

possible that some individuals could 

transit this area in route to haul out or 

forage. Therefore, and in order to ensure 

that the Navy is adequately authorized 

for incidental take, NMFS predicts that 

at least one individual Steller sea lion 

could be exposed to sound levels 

indicating Level B harassment per day 

of pneumatic chipping. Table 8 depicts 

the number of estimated behavioral 

harassments. 

Harbor Seal 

Harbor seals are the most abundant 

marine mammal in Hood Canal, where 

they can occur anywhere in Hood Canal 

waters year-round. The Navy detected 

harbor seals during marine mammal 

boat surveys of the waterfront area from 

July to September 2008 (Tannenbaum et 

al., 2009) and November to May 2010 

(Tannenbaum et al., 2011), as described 

previously. Harbor seals were sighted 

during every survey and were found in 

all marine habitats including nearshore 

waters and deeper water, and hauled 

out on certain manmade objects, such as 

the pontoons of the floating security 

barrier. During most of the year, all age 

and sex classes could occur in the 

project area throughout the period of 

construction activity. As there are no 

known regular pupping sites in the 

vicinity of the project area, harbor seal 

neonates are not expected to be present 

during pile removal. However, the first 

documented birth of a harbor seal at 

NBKB occurred in August 2011 at 

Carderock Pier (several miles south of 

the project site), so the presence of 

neonates is possible, if unlikely. 

Otherwise, during most of the year, all 

age and sex classes could occur in the 

project area throughout the period of 

construction activity. Harbor seal 

numbers increase from January through 

April and then decrease from May 

through August as the harbor seals move 

to adjacent bays on the outer coast of 

Washington for the pupping season. 

From April through mid-July, female 

harbor seals haul out on the outer coast 

of Washington at pupping sites to give 

birth. The main haul-out locations for 

harbor seals in Hood Canal are located 

on river delta and tidal exposed areas at 

various river mouths, with the closest 

haul-out area to the project area being 

10 mi (16 km) southwest of NBKB 

(London, 2006). Please see Figure 4–1 of 

the Navy’s application for a map of 

haul-out locations in relation to the 

project area. 

Jeffries et al. (2003) conducted aerial 

surveys of the harbor seal population in 

Hood Canal in 1999 for the Washington 

Department of Fish and Wildlife and 

reported 711 harbor seals hauled out. 

The authors adjusted this abundance 

with a correction factor of 1.53 to 

account for seals in the water, which 

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were not counted, and estimated that 

there were 1,088 harbor seals in Hood 

Canal. The correction factor (1.53) was 

based on the proportion of time seals 

spend on land versus in the water over 

the course of a day, and was derived by 

dividing one by the percentage of time 

harbor seals spent on land. These data 

came from tags (VHF transmitters) 

applied to harbor seals at six areas 

(Grays Harbor, Tillamook Bay, Umpqua 

River, Gertrude Island, Protection/Smith 

Islands, and Boundary Bay, BC) within 

two different harbor seal stocks (the 

coastal stock and the inland waters of 

WA stock) over four survey years. The 

Hood Canal population is part of the 

inland waters stock, and while not 

specifically sampled, Jeffries et al. 

(2003) found the VHF data to be broadly 

applicable to the entire stock. The 

tagging research in 1991 and 1992 

conducted by Huber et al. (2001) and 

Jeffries et al. (2003) used the same 

methods for the 1999 and 2000 survey 

years. These surveys indicated that 

approximately 35 percent of harbor 

seals are in the water versus hauled out 

on a daily basis (Huber et al., 2001; 

Jeffries et al., 2003). Exposures were 

calculated using a density derived from 

the number of harbor seals that are 

present in the water at any one time 

(35 percent of 1,088, or approximately 

381 individuals), divided by the area of 

the Hood Canal (291 km 2 [112 mi 2]) 

and the formula presented previously. 

NMFS recognizes that over the course 

of the day, while the proportion of 

animals in the water may not vary 

significantly, different individuals may 

enter and exit the water. However, finescale data on harbor seal movements 

within the project area on time 

durations of less than a day are not 

available. Previous monitoring 

experience from Navy actions 

conducted from July-October 2011 in 

the same project area has indicated that 

this density provides an appropriate 

estimate of potential exposures. Data 

from those monitoring efforts are 

currently in post-processing and are not 

available in report form at this time. 

However, the density of harbor seals 

calculated in this manner (1.3 animals/ 

km 2) is corroborated by results of the 

Navy’s vessel-based marine mammal 

surveys at NBKB in 2008 and 2009–10, 

in which an average of five individual 

harbor seals per survey was observed in 

the 3.9 km 2 survey area (density = 1.3 

animals/km 2) (Tannenbaum et al., 2009, 

2011). Table 8 depicts the number of 

estimated behavioral harassments. 

Humpback Whales 

One humpback whale has recently 

been documented in Hood Canal. This 

individual was originally sighted on 

January 27, 2012 and, while potentially 

still present, was last reported on 

February 23, 2012. Although known to 

be historically abundant in the inland 

waters of Washington, no other 

confirmed documentation of humpback 

whales in Hood Canal is available. Their 

presence has likely not occurred in 

several decades, with the last known 

reports being anecdotal accounts of 

three humpback sightings from 1972– 

82. Although it cannot be confirmed 

that this individual has departed the 

Hood Canal, with the absence of 

sighting records since February 23 

(following regular sightings between 

January 27–February 23) and the lack of 

any historical regular occurrence in the 

Hood Canal it is likely that this 

individual has departed and that no 

humpback whales would be present in 

the proposed action area. In addition, 

the proposed action is estimated to 

occur for only 15 days, with short pile 

removal durations per day. As described 

before, cetaceans are not known from 

within the WRA and it’s virtually 

impossible that an animal as large as a 

humpback whale could occur within the 

WRA; therefore, sound from pneumatic 

chipping, which is not expected to 

extend beyond the floating security 

barrier, would not have the potential to 

affect humpback whales. NMFS believes 

that the possibility for incidental take of 

humpback whales is discountable. In 

addition to the preceding rationale 

given in support of this belief, a density 

was derived from the available 

information: One humpback whale 

ranging through the Hood Canal (291 

km2), or 0.003 animals/km2. Using this 

density and the formula given 

previously, no takes are predicted. 

Killer Whales 

Transient killer whales are 

uncommon visitors to Hood Canal. 

Transients may be present in the Hood 

Canal anytime during the year and 

traverse as far as the project site. 

Resident killer whales have not been 

observed in Hood Canal, but transient 

pods (six to eleven individuals per 

event) were observed in Hood Canal for 

lengthy periods of time (59–172 days) in 

2003 (January–March) and 2005 

(February–June), feeding on harbor seals 

(London, 2006). 

These whales used the entire expanse 

of Hood Canal for feeding. Subsequent 

aerial surveys suggest that there has not 

been a sharp decline in the local seal 

population from these sustained feeding 

events (London, 2006). Based on this 

data, the density for transient killer 

whales in the Hood Canal for January to 

June is 0.038/km2 (eleven individuals 

divided by the area of the Hood Canal 

[291 km2]). Table 8 depicts the number 

of estimated behavioral harassments. 

Dall’s Porpoise 

Dall’s porpoises may be present in the 

Hood Canal year-round and could occur 

as far south as the project site. Their use 

of inland Washington waters, however, 

is mostly limited to the Strait of Juan de 

Fuca. The Navy conducted vessel-based 

surveys of the waterfront area in 2008– 

10 (Tannenbaum et al., 2009, 2011). 

During one of the surveys a Dall’s 

porpoise was sighted in August in the 

deeper waters off Carlson Spit. 

In the absence of an abundance 

estimate for the entire Hood Canal, a 

density was derived from the waterfront 

survey by the number of individuals 

seen divided by total number of 

kilometers of survey effort (18 surveys 

with approximately 3.9 km2 [1.5 mi2] of 

effort each), assuming strip transect 

surveys. In the absence of any other 

survey data for the Hood Canal, this 

density is assumed to be throughout the 

project area. Exposures were calculated 

using the formula presented previously. 

Table 8 depicts the number of estimated 

behavioral harassments. 

Harbor Porpoise 

Harbor porpoises may be present in 

the Hood Canal year-round; their 

presence had previously been 

considered rare. During waterfront 

surveys of NBKB nearshore waters from 

2008–10 only one harbor porpoise had 

been seen in 18 surveys of 3.9 km2 each. 

However, during monitoring of recent 

Navy actions at NBKB, several sightings 

indicated that their presence may be 

more frequent in deeper waters of Hood 

Canal than had been believed on the 

basis of existing survey data and 

anecdotal evidence. Subsequently, the 

Navy conducted dedicated vessel-based 

line transect surveys on days when no 

construction activity occurred (due to 

security, weather, etc.), described 

previously in this document, with 

regular observations of harbor porpoise 

groups. Sightings in the deeper waters 

of Hood Canal ranged up to eleven 

individuals, with an average of 

approximately six animals sighted per 

survey day (Navy, in prep.). 

Sightings of harbor porpoises during 

these surveys were used to generate a 

density for Hood Canal. Based on 

guidance from other line transect 

surveys conducted for harbor porpoises 

using similar monitoring parameters 

(e.g., boat speed, number of observers) 

(Barlow, 1988; Calambokidis et al., 

1993; Caretta et al., 2001), the Navy 

determined the effective strip width for 

the surveys to be 1 km, or a 

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25434 Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 

perpendicular distance of 500 m from 

the transect to the left or right of the 

vessel. The effective strip width was set 

at the distance at which the detection 

probability for harbor porpoises was 

equivalent to one, which assumes that 

all individuals on a transect are 

detected. Only sightings occurring 

within the effective strip width were 

used in the density calculation. By 

multiplying the trackline length of the 

surveys by the effective strip width, the 

total area surveyed during the surveys 

was 259.01 km2. Thirty-five individual 

harbor porpoises were sighted within 

this area, resulting in a density of 0.135 

animals per km2. To account for 

availability bias, or the animals which 

are unavailable to be detected because 

they are submerged, the Navy utilized a 

g(0) value of 0.54, derived from other 

similar line transect surveys (Barlow, 

1988; Calambokidis et al., 1993; Carretta 

et al., 2001). This resulted in a density 

of 0.250 harbor porpoises per km2. For 

comparison, 274.27 km2 of trackline 

survey effort in nearby Dabob Bay 

produced a corrected density estimate of 

0.203 harbor porpoises per km2. 

Exposures were calculated using the 

formula described previously. Table 8 

depicts the number of estimated 

behavioral harassments. 

Potential takes could occur if 

individuals of these species move 

through the area on foraging trips when 

pile removal is occurring. Individuals 

that are taken could exhibit behavioral 

changes such as increased swimming 

speeds, increased surfacing time, or 

decreased foraging. Most likely, 

individuals may move away from the 

sound source and be temporarily 

displaced from the areas of pile 

removal. Potential takes by disturbance 

would likely have a negligible shortterm effect on individuals and not result 

in population-level impacts. 

TABLE 8—NUMBER OF POTENTIAL INCIDENTAL TAKES OF MARINE MAMMALS WITHIN VARIOUS ACOUSTIC THRESHOLD

ZONES

Species Density/ 

abundance 

Underwater Airborne 

Total 

proposed 

authorized 

takes 

Injury 

threshold 1

Disturbance 

threshold— 

vibratory 

removal 

(120 dB) 

Disturbance 

threshold— 

pneumatic 

chipping 

(120 dB) 

Disturbance 

threshold 2

California sea lion .................................. 3 26 .2 0 * 390 * 32 0 422 

Steller sea lion ....................................... 3 1 .2 0 * 60 * 32 0 92 

Harbor seal ............................................ 1 .31 0 705 32 0 737 

Humpback whale ................................... 0 .003 0 0 0 N/A 0 

Killer whale ............................................. 0 .038 0 15 0 N/A 15 

Dall’s porpoise ....................................... 0 .014 0 15 0 N/A 15 

Harbor porpoise ..................................... 0 .250 0 135 0 N/A 135 

Total ................................................ .......................... 0 1,320 96 0 1,416 

* See preceding species-specific discussions for description of take estimate. 

1Acoustic injury threshold is 190 dB for pinnipeds and 180 dB for cetaceans. No activity would produce source levels equal to 190 dB, while 

only vibratory removal would produce a source level of 180 dB. 2Acoustic disturbance threshold is 100 dB for sea lions and 90 dB for harbor seals. NMFS does not believe that pinnipeds would be available 

for airborne acoustic harassment because they are known to haul-out only at locations well outside the zone in which airborne acoustic harassment could occur; nevertheless, calculations predict that no incidental take would occur as a result of airborne sound. 3Figures presented are abundance numbers, not density, and are calculated as the average of average daily maximum numbers per month. 

Abundance numbers are rounded to the nearest whole number for take estimation. 

Negligible Impact and Small Numbers 

Analysis and Preliminary 

Determination 

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.’’ In making a 

negligible impact determination, NMFS 

considers a variety of factors, including 

but not limited to: (1) The number of 

anticipated mortalities; (2) the number 

and nature of anticipated injuries; 

(3) the number, nature, intensity, and 

duration of Level B harassment; and 

(4) the context in which the take occurs. 

Pile removal activities associated with 

the wharf rehabilitation project, as 

outlined previously, have the potential 

to disturb or displace marine mammals. 

Specifically, the proposed activities may 

result in take, in the form of Level B 

harassment (behavioral disturbance) 

only, from underwater sounds generated 

through pile removal. No mortality, 

serious injury, or Level A harassment is 

anticipated given the nature of the 

activity (i.e., non-pulsed sound with 

low source levels) and measures 

designed to minimize the possibility of 

injury to marine mammals, while Level 

B harassment would be reduced to the 

level of least practicable adverse impact 

for the same reasons. Specifically, these 

removal methods would produce lower 

source levels than would pile 

installation with a vibratory hammer, 

which does not have significant 

potential to cause injury to marine 

mammals due to its sound source 

characteristics and relatively low source 

levels. Pile removal would either not 

start or be halted if marine mammals 

approach the shutdown zone (described 

previously in this document). The pile 

removal activities analyzed here carry 

significantly less risk of impact to 

marine mammals than did other 

construction activities analyzed and 

monitored within the Hood Canal, 

including two recent projects conducted 

by the Navy at the same location (test 

pile project and the first year of 

EHW–1 pile replacement work) as well 

as work conducted in 2005 for the Hood 

Canal Bridge (SR–104) by the 

Washington Department of 

Transportation. These activities have 

taken place with no reported injuries or 

mortality to marine mammals. 

The proposed numbers of authorized 

take for marine mammals would be 

considered small relative to the relevant 

stocks or populations even if each 

estimated taking occurred to a new 

individual—an extremely unlikely 

scenario. The proposed numbers of 

authorized take represent 5 percent of 

the relevant stock for harbor seals, 4.2 

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Federal Register / Vol. 77, No. 83 / Monday, April 30, 2012 / Notices 25435 

percent for transient killer whales, and 

1.3 percent for harbor porpoises; the 

proposed numbers are less than 1 

percent for the remaining species. 

However, even these low numbers 

represent potential instances of take, not 

the number of individuals taken. That 

is, it is likely that a relatively small 

subset of Hood Canal harbor seals, 

which is itself a small subset of the 

regional stock, would be harassed by 

project activities. 

For example, while the available 

information and formula estimate that 

as many as 737 exposures of harbor 

seals to stimuli constituting Level B 

harassment could occur, that number 

represents some portion of the 

approximately 1,088 harbor seals 

resident in Hood Canal (approximately 

7 percent of the regional stock) that 

could potentially be exposed to sound 

produced by pile removal activities on 

multiple days during the project. No 

rookeries are present in the project area, 

there are no haul-outs other than those 

provided opportunistically by manmade objects, and the project area is not 

known to provide foraging habitat of 

any special importance. 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. Thus, even 

repeated Level B harassment of some 

small subset of the overall stock is 

unlikely to result in any significant 

realized decrease in viability for Hood 

Canal harbor seals, and thus would not 

result in any adverse impact to the stock 

as a whole. 

NMFS has preliminarily determined 

that the impact of the previously 

described wharf rehabilitation project 

may result, at worst, in a temporary 

modification in behavior (Level B 

harassment) of small numbers of marine 

mammals. No injury, serious injury, or 

mortality is anticipated as a result of the 

specified activity, and none is proposed 

to be authorized. Additionally, animals 

in the area are not expected to incur 

hearing impairment (i.e., TTS or PTS) or 

non-auditory physiological effects. For 

pinnipeds, the absence of any major 

rookeries and only a few isolated and 

opportunistic haul-out areas near or 

adjacent to the project site means that 

potential takes by disturbance would 

have an insignificant short-term effect 

on individuals and would not result in 

population-level impacts. Similarly, for 

cetacean species the absence of any 

known regular occurrence adjacent to 

the project site means that potential 

takes by disturbance would have an 

insignificant short-term effect on 

individuals and would not result in 

population-level impacts. Due to the 

nature, degree, and context of 

behavioral harassment anticipated, the 

activity is not expected to impact rates 

of recruitment or survival. 

While the number of marine 

mammals potentially incidentally 

harassed would depend on the 

distribution and abundance of marine 

mammals in the vicinity of the survey 

activity, the number of potential 

harassment takings is estimated to be 

small relative to regional stock or 

population number, and has been 

mitigated to the lowest level practicable 

through incorporation of the proposed 

mitigation and monitoring measures 

mentioned previously in this document. 

This activity is expected to result in a 

negligible impact on the affected species 

or stocks. The eastern DPS of the Steller 

sea lion is listed as threatened under the 

ESA; no other species for which take 

authorization is requested are either 

ESA-listed or considered depleted 

under the MMPA. 

Based on the analysis contained 

herein of the likely effects of the 

specified activity on marine mammals 

and their habitat, and taking into 

consideration the implementation of the 

mitigation and monitoring measures, 

NMFS preliminarily finds that the 

proposed wharf construction project 

would result in the incidental take of 

small numbers of marine mammals, by 

Level B harassment only, and that the 

total taking from the activity would 

have a negligible impact on the affected 

species or stocks. 

Impact on Availability of Affected 

Species or Stock for Taking for 

Subsistence Uses 

No tribal subsistence hunts are held 

in the vicinity of the project area; thus, 

temporary behavioral impacts to 

individual animals would not affect any 

subsistence activity. Further, no 

population or stock level impacts to 

marine mammals are anticipated or 

authorized. As a result, no impacts to 

the availability of the species or stock to 

the Pacific Northwest treaty tribes are 

expected as a result of the proposed 

activities. Therefore, no relevant 

subsistence uses of marine mammals are 

implicated by this action. 

Endangered Species Act (ESA) 

There are two ESA-listed marine 

mammal species with known 

occurrence in the project area: The 

eastern DPS of the Steller sea lion, listed 

as threatened, and the humpback whale, 

listed as endangered. Because of the 

potential presence of these species, the 

Navy has requested a formal 

consultation with the NMFS Northwest 

Regional Office under section 7 of the 

ESA. NMFS’ Office of Protected 

Resources has also initiated formal 

consultation on its authorization of 

incidental take of Steller sea lions. 

These consultations are in progress. 

These species do not have critical 

habitat in the action area. 

National Environmental Policy Act 

(NEPA) 

In compliance with the National 

Environmental Policy Act of 1969 (42 

U.S.C. 4321 et seq.), as implemented by 

the regulations published by the 

Council on Environmental Quality (40 

CFR parts 1500–1508), and NOAA 

Administrative Order 216–6, the Navy 

prepared an Environmental Assessment 

(EA) to consider the direct, indirect and 

cumulative effects to the human 

environment resulting from the pile 

replacement project. NMFS adopted that 

EA in order to assess the impacts to the 

human environment of issuance of an 

IHA to the Navy. NMFS signed a 

Finding of No Significant Impact 

(FONSI) on May 17, 2011. On the basis 

of new information related to the 

occurrence of marine mammals in the 

Hood Canal, the Navy is preparing a 

supplement to that EA. NMFS will 

review that document and, if 

appropriate, issue a new FONSI. 

Proposed Authorization 

As a result of these preliminary 

determinations, NMFS proposes to 

authorize the take of marine mammals 

incidental to the Navy’s wharf 

rehabilitation project, provided the 

previously mentioned mitigation, 

monitoring, and reporting requirements 

are incorporated. 

Dated: April 24, 2012. 

Helen M. Golde, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2012–10370 Filed 4–27–12; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

RIN 0648–XB109 

Taking and Importing Marine 

Mammals; Naval Explosive Ordnance 

Disposal School Training Operations 

at Eglin Air Force Base, Florida 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

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