5674 Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

50 CFR Part 217 

[Docket No. 240122–0021] 

RIN 0648–BL79 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to the Naval 

Magazine Indian Island Ammunition 

Wharf Maintenance and Pile 

Replacement Project, Puget Sound, 

Washington 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Final rule. 

SUMMARY: NMFS, upon request from the 

U.S. Navy (Navy), issues these 

regulations pursuant to the Marine 

Mammal Protection Act (MMPA) to 

govern the taking of marine mammals 

during the maintenance and pile 

replacement construction activities at 

the Ammunition Wharf at Naval 

Magazine (NAVMAG) Indian Island in 

Puget Sound, Washington, over the 

course of 5 years (2024 to 2029). These 

regulations, which allow for the 

issuance of Letters of Authorization 

(LOA) for the incidental take of marine 

mammals during the described activities 

and timeframes, prescribe the 

permissible methods of taking and other 

means of effecting the least practicable 

adverse impact on marine mammal 

species and their habitat, and establish 

requirements pertaining to the 

monitoring and reporting of such taking. 

DATES: Effective October 1, 2024, until 

September 30, 2029. 

ADDRESSES: A copy of the Navy’s 

application, NMFS’ final rule, and other 

supporting documents may be obtained 

online at https://

www.fisheries.noaa.gov/action/ 

incidental-take-authorization-takingmarine-mammals-incidental-navalmagazine-indian. In case of problems 

accessing these documents, please use 

the contact listed here (see FOR FURTHER

INFORMATION CONTACT). 

FOR FURTHER INFORMATION CONTACT: 

Robert Pauline, Office of Protected 

Resources, NMFS, ITP.pauline@

noaa.gov, (301) 427–8401. 

SUPPLEMENTARY INFORMATION: 

Purpose and Need for Regulatory 

Action 

We received an application from the 

Navy requesting 5-year regulations and 

authorization to incidentally take 

multiple species of marine mammals. 

This rule establishes a framework under 

the authority of the MMPA (16 U.S.C. 

1361 et seq.) to allow for the 

authorization of take by Level A and 

Level B harassment of marine mammals 

incidental to the Navy’s maintenance 

and pile replacement construction 

activities at the Ammunition Wharf at 

NAVMAG Indian Island in Puget 

Sound, Washington. Please see 

Background below for definitions of 

harassment. 

Legal Authority for the Action 

Section 101(a)(5)(A) of the MMPA (16 

U.S.C. 1371(a)(5)(A)) directs 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 for up to 5 years if, 

after notice and public comment, the 

agency makes certain findings and 

issues regulations that set forth 

permissible methods of taking pursuant 

to that activity and other means of 

effecting the ‘‘least practicable adverse 

impact’’ on the affected species or 

stocks and their habitat (see the 

discussion below in the Mitigation 

section), as well as monitoring and 

reporting requirements. Section 

101(a)(5)(A) of the MMPA and the 

implementing regulations at 50 CFR part 

217, subpart I provide the legal basis for 

issuing this rule containing 5-year 

regulations, and for any subsequent 

LOAs. As directed by this legal 

authority, this rule contains mitigation, 

monitoring, and reporting requirements. 

Summary of Major Provisions 

The following is a summary of the 

major provisions of this final rule 

regarding Navy construction activities. 

These provisions include, but are not 

limited to: 

• Monitoring of the construction 

areas to detect the presence of marine 

mammals before beginning construction 

activities; 

• Shutdown of construction activities 

under certain circumstances to avoid 

injury of marine mammals; 

• Soft start for impact pile driving to 

allow marine mammals the opportunity 

to leave the area prior to beginning 

impact pile driving at full power; and 

• Use of bubble curtains to attenuate 

sound levels when impact driving steel 

piles. 

Background 

The MMPA prohibits the ‘‘take’’ of 

marine mammals, with certain 

exceptions. Sections 101(a)(5)(A) and 

(D) of the MMPA (16 U.S.C. 1361 et 

seq.) direct the Secretary of Commerce 

(as delegated to NMFS) 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 

proposed or, if the taking is limited to 

harassment, a notice of a proposed 

incidental take 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) and will not have 

an unmitigable adverse impact on the 

availability of the species or stock(s) for 

taking for subsistence uses (where 

relevant). Further, NMFS must prescribe 

the permissible methods of taking and 

other ‘‘means of effecting the least 

practicable adverse impact’’ on the 

affected species or stocks and their 

habitat, paying particular attention to 

rookeries, mating grounds, and areas of 

similar significance, and on the 

availability of the species or stocks for 

taking for certain subsistence uses 

(referred to in shorthand as 

‘‘mitigation’’); and requirements 

pertaining to the mitigation, monitoring 

and reporting of the takings are set forth. 

The definitions of all applicable MMPA 

statutory terms cited above are included 

in the relevant sections below. 

Summary of Request 

In May 2021, NMFS received an 

application from the Navy requesting 

authorization to take small numbers of 

eight species of marine mammals 

incidental to construction activities at 

the Ammunition Wharf at NAVMAG 

Indian Island. The Navy requested 

regulations that would establish a 

process for authorizing such take via an 

LOA. NMFS reviewed the Navy’s 

application, and sent initial questions 

regarding the application to the Navy on 

October 5, 2021. The Navy addressed 

the questions and submitted a revised 

LOA application on March 24, 2022. 

After additional questions were sent by 

NMFS, the Navy submitted another 

revised application on May 13, 2022, 

and the revised application was deemed 

adequate and complete on June 9, 2022. 

The application was published for 

public review and comment on August 

4, 2022 (87 FR 47722). Following 

publication of the application, the Navy 

delayed the project start date by 1 year. 

We published a notice of the proposed 

rulemaking in the Federal Register on 

October 30, 2023 (88 FR 74113). There 


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Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 5675 

are no changes from the proposed to the 

final rulemaking. 

The regulations will be valid for 5 

years, from October 1, 2024, until 

September 30, 2029, and allow NMFS to 

authorize the Navy to take eight species 

of marine mammals by Level B 

harassment and, additionally, one of 

these species by Level A harassment, 

incidental to construction activities 

related to the maintenance and pile 

replacement project at the Ammunition 

Wharf at NAVMAG Indian Island in 

Puget Sound, Washington. Neither the 

Navy nor NMFS expect serious injury or 

mortality to result from this activity. 

Description of Activity 

Overview 

The Navy plans to replace defective 

structural concrete and fender piles as 

well as conduct maintenance and repair 

activities on the Ammunition Wharf at 

NAVMAG Indian Island. Maintaining 

this wharf structure is vital to sustaining 

the Navy’s mission and ensuring 

readiness. The Navy plans to replace up 

to 118 structural concrete piles or fender 

piles, conduct maintenance, and engage 

in repair activities over a 7-year period 

on the Ammunition Wharf. However, 

the LOA may only be valid for 5 years. 

The Navy plans to conduct necessary 

work, including impact and vibratory 

pile driving, to replace and maintain the 

wharf structure. Under the 5-year rule, 

up to 110 structurally unsound 

structural piles or fender piles will be 

replaced. Structural concrete piles will 

be replaced with 24-inch concrete piles 

and old fender piles will be replaced 

with 14-inch steel H piles or 18.75-inch 

composite piles. Up to eight steel piles 

may also be installed in addition to the 

structural concrete piles if necessary. 

The 2 years following the expiration of 

the rule will consist of removal and 

installation of concrete piles, and 

maintenance and repair work. The Navy 

will request incidental take 

authorizations as necessary for the final 

2 years of work. 

Dates and Duration 

The regulations and LOA will be valid 

for a period of 5 years from October 1, 

2024, until September 30, 2029. All pile 

driving will be conducted during the 

prescribed in-water work window of 

October 1 to January 15 to avoid 

conducting activities when juvenile 

salmonids are most likely to be present. 

A conservative estimate of annual pile 

driving days over the duration of the 5- 

year LOA is based on the assumption 

that pile driving rates will be relatively 

slow and will take approximately 24 

days per year with up to 22 concrete 

piles or fender piles and up to 2 steel 

piles installed per year. Conservatively, 

one concrete pile will be installed per 

day using jetting followed by proofing 

with an impact hammer. There may be 

extra days for additional proofing or 

weather/equipment delays. Actual daily 

production rates may be higher (often 

two piles are installed in a day), 

resulting in fewer actual pile driving 

days. 

Specific Geographic Region 

NAVMAG Indian Island is located 

near Port Hadlock in Jefferson County, 

Washington, southeast of Port 

Townsend, at the northeast corner of the 

Olympic Peninsula (figure 1). The 

island is approximately 8 kilometers 

(km) long and 2 km wide, and 

comprises approximately 11 km square 

(km2). NAVMAG Indian Island is 

located between Port Townsend Bay 

and Kilisut Harbor. The Federal 

Government owns the island and 

provides an easement on a small portion 

of the southern extent of the island to 

Washington State Department of 

Transportation for access to 

Marrowstone Island along State Route 

116. NAVMAG Indian Island is the West 

Coast ammunition ordnance storage 

center supporting the U.S. Navy Pacific 

Fleet. 

NAVMAG Indian Island occupies 

approximately 19 km of shoreline 

within Port Townsend Bay. There are 

two marine structures located at 

NAVMAG Indian Island, the 

Ammunition Wharf and the Small Craft 

Pier, but only the Ammunition Wharf 

activities are addressed in this rule. Its 

primary mission is to load, offload, and 

provide storage and logistics 

management for ordnance used on Navy 

vessels. 


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5676 Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 

Detailed Description of the Specified 

Activity 

NAVMAG Indian Island is the West 

Coast ammunition ordnance storage 

center supporting the U.S. Navy Pacific 

Fleet. Its primary mission is to load, 

offload, and provide storage and 

logistics management for ordnance used 

on Navy vessels. Construction of the 

Ammunition Wharf was completed in 

1979, and there are a total of 1,783 piles 

in the Ammunition Wharf: 1,391 

structural piles, 306 fender piles and 86 

Operations Building piles. 

The Ammunition Wharf was 

originally constructed using precast 

concrete piles. As a result of the steam 

curing process used at that time, an 

unknown quantity of piling is 

susceptible to a potentially catastrophic 

condition called Delayed Ettringite 

Formation (DEF). DEF is a result of high 

early temperatures in the concrete, 

which prevents the normal formation of 

ettringite. DEF occurs rapidly and 

without warning. 

The Navy schedules inspections on 

waterfront facilities that usually occur 

every 3 years, but due to DEF at the 

Ammunition Wharf, inspections for that 

structure occur every two years. Based 

on the most recent inspection in 2021, 

there are 161 piles (158 under 

Ammunition Pier and three under the 

Operations Building at Ammunition 

Wharf) with some appreciable level of 

DEF damage (most or all of those piles 

will be replaced). More piles with DEF 

damage may be detected and therefore 

may need to be replaced over the 

duration of the LOA. 

Table 1 shows the details of the 

construction activities which are 

described below in greater detail. 


ddrumheller on DSK120RN23PROD with RULES2ER29JA24.000</GPH>

l.tllmt 

CJNavy PlQJ)8lty Boundary 

ClDocks And Wharfs ·•· s 

.......... ---"'-'---·--- 0 

0 1 

- NAVMAG 

Indian Island 

Figure 1 -- Location of Ammunition Wharf on Naval Magazine Indian Island 
Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 5677 

TABLE 1—PROJECT COMPONENTS FOR

PILE REPLACEMENT FOR THE AMMUNITION WHARF

Wharf structure 

(in-water 

construction) 

Construction details 

Total Piles ...... Up to 118 piles installed 

over 5 years (including up 

to 8 steel piles, with the 

remainder concrete). 

Quantity of 

concrete 

piles (24- 

inch).

Up to 22 per year over 5 

years. 

Quantity of 

permanent 

steel piles 

(36-inch).

Up to two per year (Maximum of eight) over 5 

years (Currently no steel 

pile installation is planned, 

installation would depend 

on future pile inspections). 

Pile Removal 

Method.

Cutting. 

Pile Installation 

Method.

Jetting and impact driving of 

concrete piles; Vibratory 

and impact driving of steel 

piles. No simultaneous pile 

driving will occur. 

Quantity of 

piles above 

–30 feet 

MLLW.

All. 

Maximum 

number of 

piles driven 

per day (approximately).

Two concrete piles per day. 

One steel pile per day. 

Total duration 

of impact 

pile driving.

No more than 45 minutes 

per day (mean = 10 minutes for concrete piles; 15 

minutes for steel piles). 

Maximum duration of vibratory pile 

driving.

No more than 30 minutes 

(mean = 10 minutes per 

steel pile). 

Marine Construction Duration (including inwater restrictions).3.5 months per year (In 

water work window: October 1 through January 15). 

Removal of Existing Piles 

After demolition of the deck portions 

of the wharf located above the 

waterline, three methods of pile removal 

(cutting/chipping, clamshell removal, 

and direct pull) may be used. However, 

hydraulic cutting will be the primary 

method of pile removal due to working 

under the wharf and the DEF damage to 

the piles. In some cases, piles may be 

cut at or below the mudline, with the 

below-mudline portion of the pile left in 

place. None of these pile removal 

activities are anticipated to result in 

take of marine mammals; therefore, they 

are not discussed further beyond the 

brief elaboration on jetting and pile 

cutting provided below. 

Pile Installation 

Three methods of pile installation for 

concrete and steel piles will be used 

(vibratory, jetting, and impact) 

depending on the type of pile and site 

conditions. Only one pile will be 

installed at a time; no simultaneous pile 

driving will occur. These methods are 

described below. 

The primary methods of concrete pile 

installation will be water jetting to 

within 3 meters (m) of final depth and 

then impact pile driving to set or proof 

the final 3 m. Water jetting aids the 

penetration of a pile into a dense sand 

or sandy gravel stratum. Water jetting 

utilizes a carefully directed and 

pressurized flow of water at the pile tip, 

which disturbs a ring of soils directly 

beneath it. The jetting technique 

liquefies the soils at the pile tip during 

pile placement, reducing the friction 

and interlocking between adjacent sub 

grade soil particles around the water jet. 

For load-bearing structures, an impact 

hammer is typically required to strike a 

pile a number of times to ensure it has 

met the load-bearing specifications; this 

is referred to as ‘‘proofing.’’ Loadbearing piles installed with water jetting 

will still need to be proofed with an 

impact pile driver. 

A vibratory hammer will be used to 

install the structural steel piles and 

fender piles. The primary method of 

pile installation for steel piles will be 

vibratory to within 3 m of final depth 

and then impact pile driving to set or 

proof the final 3 m. The vibratory pile 

driver method is a technique that may 

be used in pile installation where the 

substrate allows. Use of this technique 

will be limited in very hard substrates. 

This process begins by placing a choker 

cable around a pile and lifting it into 

vertical position with a crane. The pile 

is then lowered into position and set in 

place at the mudline. The pile is held 

steady while the vibratory driver installs 

the pile to the required tip elevation. In 

some substrates, a vibratory driver may 

be unable to advance a pile until it 

reaches the required depth. In these 

cases, an impact hammer will be used 

to advance the pile to the required 

depth. 

Impact hammers will be used to proof 

concrete piles that have been jetted to 

depth or steel piles that have been 

driven using the vibratory method. 

Proofing involves impact pile driving to 

determine if the pile has been driven to 

the proper load-bearing specifications 

within the substrate. Proofing of 

concrete piles at the Ammunition Wharf 

in 2015 and 2016 required 200 to 600 

strikes per pile to complete (Navy, 

2016). 

Impact hammers have a heavy piston 

that moves up and down striking the top 

of the pile and driving the pile into the 

substrate from the downward force of 

the hammer. Impact hammer pile 

proofing can typically take a minute or 

less to 30 minutes depending on pile 

type, pile size, and conditions (i.e., 

bedrock, loose soils, etc.) to reach the 

required tip elevation. 

The Navy states that piles will be 

advanced to the extent practicable with 

a vibratory driver and only impact 

driven when required for proofing or 

when a pile cannot be advanced with a 

vibratory driver due to hard substrate 

conditions. 

Existing piles that are structurally 

sound may require additional repair 

activities. Such activities could include 

wetwell repair; recoating of piles and 

mooring fittings; installation or 

replacement of passive cathode 

protection systems; repair and 

replacement of pile caps; concrete 

repair; mooring foundation and 

substructure repair; replacement of 

components (e.g., hand rails, safety 

ladders, light poles); and rewrapping or 

replacement of steel cable straps on 

dolphins. These repairs are described in 

greater detail in the Navy’s application 

but will not result in the take of marine 

mammals and are not discussed further. 

Operation of the following equipment 

types is not reasonably expected to 

result in take of marine mammals and 

will not be discussed further beyond the 

brief summaries provided below: 

• Jetting produces much lower sound 

levels (approximately 147.5 decibel (dB) 

Root Mean Square (RMS); NAVFAC SW, 

2020) than vibratory pile driving 166 dB 

RMS (Navy, 2015). The sounds 

produced by jetting are of similar 

frequencies to the sounds produced by 

vessels, and are anticipated to diminish 

to background noise levels (or be 

masked by background noise levels) in 

Port Townsend Bay. 

• Hydraulic cutting will be used be 

used to assist with removal of piles. 

Similar to jetting, the sounds produced 

by cutting are of similar frequencies to 

the sounds produced by vessels 

(NAVFAC SW, 2020), and are 

anticipated to diminish to background 

noise levels (or be masked by 

background noise levels) in Port 

Townsend Bay relatively close to the 

Ammunition Wharf. Cutting of 24-inch 

concrete piles also produces much 

lower sound levels (approximately 

141.4 dB RMS; (NAVFAC SW, 2020)) 

than vibratory pile driving 166 dB RMS 

(Navy, 2015). 

Mitigation, monitoring, and reporting 

measures are described in detail later in 


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5678 Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 

this document (please see Mitigation 

and Monitoring and Reporting). 

Comments and Responses 

A notice of NMFS’ proposed 

rulemaking to the Navy was published 

in the Federal Register on October 30, 

2023 (88 FR 74113). That proposed rule 

described, in detail, the Navy’s 

activities, the marine mammal species 

that may be affected by the activities, 

and the anticipated effects on marine 

mammals. In that proposed rule, we 

requested public input on the request 

for authorization described therein, our 

analyses, the proposed authorization, 

and any other aspect of the notice of 

proposed rulemaking, and requested 

that interested persons submit relevant 

information, suggestions, and 

comments. This proposed rule was 

available for a 30-day public comment 

period. 

NMFS received three letters from 

private citizens during the public 

comment period. These comments were 

outside the scope of this rule. There are 

no changes from the proposed to the 

final rulemaking as a result of these 

comments. 

Description of Marine Mammals in the 

Area of Specified Activities 

Sections 3 and 4 of the application 

summarize available information 

regarding status and trends, distribution 

and habitat preferences, and behavior 

and life history of the potentially 

affected species. NMFS fully considered 

all of this information, and we refer the 

reader to these descriptions instead of 

reprinting the information. Additional 

information regarding population trends 

and threats may be found in NMFS’ 

Stock Assessment Reports (SARs; 

https://www.fisheries.noaa.gov/ 

national/marine-mammal-protection/ 

marine-mammal-stock-assessments) 

and more general information about 

these species (e.g., physical and 

behavioral descriptions) may be found 

on NMFS’ website (https://

www.fisheries.noaa.gov/find-species). 

Table 2 lists all species or stocks that 

could occur during this activity, and 

summarizes information related to the 

population or stock, including 

regulatory status under the MMPA and 

Endangered Species Act (ESA) and 

potential biological removal (PBR), 

where known. PBR is defined by the 

MMPA as the maximum number of 

animals, not including natural 

mortalities, that may be removed from a 

marine mammal stock while allowing 

that stock to reach or maintain its 

optimum sustainable population (as 

described in NMFS’ SARs). While no 

serious injury or mortality is expected to 

occur, PBR and annual serious injury 

and mortality from anthropogenic 

sources are included here as gross 

indicators of the status of the species or 

stocks and other threats. 

Marine mammal abundance estimates 

presented in this document represent 

the total number of individuals that 

make up a given stock or the total 

number estimated within a particular 

study or survey area. NMFS’ stock 

abundance estimates for most species 

represent the total estimate of 

individuals within the geographic area, 

if known, that comprises that stock. For 

some species, this geographic area may 

extend beyond U.S. waters. All stocks 

managed under the MMPA in this 

region are assessed in NMFS’ U.S. 

Pacific Marine Mammal Stock 

Assessment Report. All values 

presented in table 2 are the most recent 

available at the time of publication and 

are available online at: https:// 

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/marinemammal-stock-assessments. 

TABLE 2—MARINE MAMMAL SPECIES 4 LIKELY TO OCCUR NEAR THE PROJECT AREA THAT MAY BE TAKEN BY THE NAVY’S

ACTIVITIES

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

Strategic 

(Y/N) 1

Stock abundance (CV, Nmin, 

most recent abundance 

survey) 2

PBR Annual 

M/SI 3

Order Artiodactyla—Cetacea—Mysticeti (baleen whales) 

Family Eschrichtiidae: 

Gray Whale ......................... (Eschrichtius robustus) ... Eastern N Pacific ...................... -,-, N 26,960 (0.05, 25,849, 2016) ..... 801 131 

Family Balaenopteridae 

(rorquals): 

Humpback Whale ............... Megaptera novaeangliae Central America/Southern Mexico—California-OregonWashington.E, D, Y 1,496 (0.171, 1,284, 2021) ....... 3.5 14.9 

Mainland Mexico—CaliforniaOregon-Washington.T, D, Y 3,477 (0.101, 3,185, 2018) ....... 43 22 

Hawaii ....................................... -, -, N 11,278 (0.56, 7,265, 2020) ....... 127 27.09 

Minke Whale ....................... Balaenoptera 

acutorostrata.

CA/OR/WA ................................ -, -, N 915 (0.792, 509, 2018) ............. 4.1 ≥0.59 

Odontoceti (toothed whales, dolphins, and porpoises) 

Family Phocoenidae (porpoises): 

Dall’s Porpoise .................... Phocoenoides dalli ......... CA/OR/WA ................................ -, -, N 16,498 (0.61, 10,286, 2019) ..... 99 ≥0.66 

Harbor Porpoise ................. Phocoena phocoena ...... Washington Inland Waters ....... -, -, N 11,233 (0.37, 8,308, 2015) ....... 66 ≥7.2 

Family Delphinidae: 

Killer Whale ........................ Orcinus orca ................... West Coast Transient ............... -, -, N 349 (N/A, 349, 2018) ................ 3.5 0.4 

Eastern North Pacific Southern 

Resident.

E, D, Y 74 (N/A, 74, 2021) .................... 0.13 ≥0.4 

Order Carnivora—Pinnipedia 

Family Otariidae (eared seals 

and sea lions): 

CA Sea Lion ....................... Zalophus californianus ... U.S. ........................................... -, -, N 257,606 (N/A, 233,515, 2014) .. 14011 >320 

Steller Sea Lion .................. Eumetopias jubatus ........ Eastern ...................................... -, -, N 43,201 (N/A, 43,201, 2017) ...... 2,592 112 

Family Phocidae (earless seals): 


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I I I I 

I I I 
Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 5679 

TABLE 2—MARINE MAMMAL SPECIES 4 LIKELY TO OCCUR NEAR THE PROJECT AREA THAT MAY BE TAKEN BY THE NAVY’S

ACTIVITIES—Continued 

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

Strategic 

(Y/N) 1

Stock abundance (CV, Nmin, 

most recent abundance 

survey) 2

PBR Annual 

M/SI 3

Harbor Seal ........................ Phoca vitulina ................. Washington Northern Inland 

Waters.

-, -, N 11,036 5 (UNK, UNK, 1999) ...... UND 9.8 

Northern Elephant Seal ...... Mirounga angustirostris .. CA Breeding ............................. -, -, N 187,386 (NA, 85,369, 2013) ..... 5122 13.7 

1Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the 

ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or 

which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically 

designated under the MMPA as depleted and as a strategic stock. 2 NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessmentreports. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. 3These values, found in NMFS’s SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated 

mortality due to commercial fisheries is presented in some cases. 4 Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy’s Committee on Taxonomy 

(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/; Committee on Taxonomy (2022)). 5The abundance estimate for this stock is greater than 8 years old and is therefore not considered current. PBR is considered undetermined for this stock, as there 

is no current minimum abundance estimate for use in calculation. We nevertheless present the most recent abundance estimates, as these represent the best available information for use in this document. 

As indicated above, all 10 species 

(with 13 managed stocks) in table 2 

temporally and spatially co-occur with 

the activity to the degree that take is 

reasonably likely to occur. However, no 

take is authorized for killer whales and 

humpback whales for the reasons 

provided in the Federal Register notice 

for the proposed rule (88 FR 74113, 

October 30, 2023). No take of these 

species is anticipated or will be 

authorized by NMFS and we do not 

discuss them further. 

A detailed description of the species 

likely to be affected by the Navy’s 

construction activities, including brief 

introductions to the species and 

relevant stocks as well as available 

information regarding population trends 

and threats, and information regarding 

local occurrence, were provided in the 

Federal Register notice for the proposed 

rule (88 FR 74113, October 30, 2023). 

Since that time, we are not aware of any 

changes in the status of these species 

and stocks; therefore, detailed 

descriptions are not provided here. 

Please refer to that Federal Register 

notice for these descriptions. Please also 

refer to the NMFS website (https://

www.fisheries.noaa.gov/find-species) for 

generalized species accounts. 

Marine Mammal Hearing 

Hearing is the most important sensory 

modality for marine mammals 

underwater, and exposure to 

anthropogenic sound can have 

deleterious effects. To appropriately 

assess the potential effects of exposure 

to sound, it is necessary to understand 

the frequency ranges marine mammals 

are able to hear. Not all marine mammal 

species have equal hearing capabilities 

(e.g., Richardson et al., 1995; Wartzok 

and Ketten, 1999; Au and Hastings, 

2008). To reflect this, Southall et al. 

(2007, 2019) recommended that marine 

mammals be divided into hearing 

groups based on directly measured 

(behavioral or auditory evoked potential 

techniques) or estimated hearing ranges 

(behavioral response data, anatomical 

modeling, etc.). Note that no direct 

measurements of hearing ability have 

been successfully completed for 

mysticetes (i.e., low-frequency 

cetaceans). Subsequently, NMFS (2018) 

described generalized hearing ranges for 

these marine mammal hearing groups. 

Generalized hearing ranges were chosen 

based on the approximately 65 dB 

threshold from the normalized 

composite audiograms, with the 

exception for lower limits for lowfrequency cetaceans where the lower 

bound was deemed to be biologically 

implausible and the lower bound from 

Southall et al. (2007) retained. Marine 

mammal hearing groups and their 

associated hearing ranges are provided 

in table 3. 

TABLE 3—MARINE MAMMAL HEARING GROUPS (NMFS, 2018) 

Hearing group Generalized hearing 

range * 

Low-frequency (LF) cetaceans (baleen whales) ..................................................................................................................... 7 Hz to 35 kHz. 

Mid-frequency (MF) cetaceans (dolphins, toothed whales, beaked whales, bottlenose whales) ........................................... 150 Hz to 160 kHz. 

High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, Cephalorhynchid, Lagenorhynchus cruciger & L. 

australis).

275 Hz to 160 kHz. 

Phocid pinnipeds (PW) (underwater) (true seals) ................................................................................................................... 50 Hz to 86 kHz. 

Otariid pinnipeds (OW) (underwater) (sea lions and fur seals) .............................................................................................. 60 Hz to 39 kHz. 

* Represents the generalized hearing range for the entire group as a composite (i.e., all species within the group), where individual species’ 

hearing ranges are typically not as broad. Generalized hearing range chosen based on ∼65 dB threshold from normalized composite audiogram, 

with the exception for lower limits for LF cetaceans (Southall et al,. 2007) and PW pinniped (approximation). 

The pinniped functional hearing 

group was modified from Southall et al. 

(2007) on the basis of data indicating 

that phocid species have consistently 

demonstrated an extended frequency 

range of hearing compared to otariids, 

especially in the higher frequency range 

(Hemila ̈ et al., 2006; Kastelein et al., 

2009; Reichmuth and Holt, 2013). 

For more detail concerning these 

groups and associated frequency ranges, 

please see NMFS (2018) for a review of 

available information. 


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Potential Effects of Specified Activities 

on Marine Mammals and Their Habitat 

The effects of underwater noise from 

the Navy’s construction activities have 

the potential to result in behavioral 

harassment of marine mammals in the 

vicinity of the project area. The notice 

of the proposed rulemaking (88 FR 

74113, October 30, 2023) included a 

discussion of the effects of 

anthropogenic noise on marine 

mammals and the potential effects of 

underwater noise from the Navy’s 

construction activities on marine 

mammals and their habitat. That 

information and analysis is referenced 

in this final rule and is not repeated 

here; please refer to the notice of the 

proposed rulemaking (88 FR 74113, 

October 30, 2023). 

Estimated Take of Marine Mammals 

This section provides an estimate of 

the number of incidental takes that may 

be authorized under this final rule, 

which will inform both NMFS’ 

consideration of ‘‘small numbers,’’ and 

the negligible impact determinations. 

Harassment is the only type of take 

expected to result from these activities. 

Except with respect to certain activities 

not pertinent here, section 3(18) of the 

MMPA defines ‘‘harassment’’ as any act 

of pursuit, torment, or annoyance, 

which (i) has the potential to injure a 

marine mammal or marine mammal 

stock in the wild (Level A harassment); 

or (ii) has the potential to disturb a 

marine mammal or marine mammal 

stock in the wild by causing disruption 

of behavioral patterns, including, but 

not limited to, migration, breathing, 

nursing, breeding, feeding, or sheltering 

(Level B harassment). 

Authorized takes will be primarily by 

Level B harassment, as use of the 

acoustic sources (i.e., vibratory and 

impact pile driving equipment) has the 

potential to result in disruption of 

behavioral patterns for individual 

marine mammals. There is also some 

potential for auditory injury (Level A 

harassment) to result, primarily for 

harbor seals (phocids) because these 

animals are known to occur in close 

proximity to the pile driving locations. 

Auditory injury is unlikely to occur for 

other hearing groups or species. The 

required mitigation and monitoring 

measures are expected to minimize the 

severity of the taking to the extent 

practicable. 

As described previously, no serious 

injury or mortality is anticipated or 

authorized for this activity. Below, we 

describe how the authorized take 

numbers are estimated. 

For acoustic impacts, generally 

speaking, we estimate take by 

considering: (1) acoustic thresholds 

above which NMFS believes the best 

available science indicates marine 

mammals will be behaviorally harassed 

or incur some degree of permanent 

hearing impairment; (2) the area or 

volume of water that will be ensonified 

above these levels in a day; (3) the 

density or occurrence of marine 

mammals within these ensonified areas; 

and (4) the number of days of activities. 

We note that while these factors can 

contribute to a basic calculation to 

provide an initial prediction of potential 

takes, additional information that can 

qualitatively inform take estimates is 

also sometimes available (e.g., previous 

monitoring results or average group 

size). Below, we describe the factors 

considered here in more detail and 

present the estimated take numbers. 

Acoustic Thresholds 

NMFS recommends the use of 

acoustic thresholds that identify the 

received level of underwater sound 

above which exposed marine mammals 

would be reasonably expected to be 

behaviorally harassed (equated to Level 

B harassment) or to incur permanent 

threshold shift (PTS) of some degree 

(equated to Level A harassment). 

Level B Harassment—Though 

significantly driven by received level, 

the onset of behavioral disturbance from 

anthropogenic noise exposure is also 

informed to varying degrees by other 

factors related to the source or exposure 

context (e.g., frequency, predictability, 

duty cycle, duration of the exposure, 

signal-to-noise ratio, distance to the 

source), the environment (e.g., 

bathymetry, other noises in the area, 

predators in the area), and the receiving 

animals (hearing, motivation, 

experience, demography, life stage, 

depth) and can be difficult to predict 

(e.g., Southall et al., 2007, 2021; Ellison 

et al., 2012). Based on what the 

available science indicates and the 

practical need to use a threshold based 

on a metric that is both predictable and 

measurable for most activities, NMFS 

typically uses a generalized acoustic 

threshold based on received level to 

estimate the onset of behavioral 

harassment. NMFS generally predicts 

that marine mammals are likely to be 

behaviorally harassed in a manner 

considered to be Level B harassment 

when exposed to underwater 

anthropogenic noise above root-meansquared pressure received levels (RMS 

sound pressure level (SPL)) of 120 dB 

(referenced to 1 micropascal (re 1 mPa)) 

for continuous (e.g., vibratory piledriving, drilling) and above RMS SPL 

160 dB re 1 mPa for non-explosive 

impulsive (e.g., seismic airguns) or 

intermittent (e.g., scientific sonar) 

sources. 

The Navy’s planned activity includes 

the use of continuous (vibratory 

hammer source type) and impulsive 

(impact hammer) sources, and therefore 

the RMS SPL thresholds of 120 and 160 

dB re 1 mPa are applicable. 

Level A harassment—NMFS’ 

Technical Guidance for Assessing the 

Effects of Anthropogenic Sound on 

Marine Mammal Hearing (Version 2.0) 

(Technical Guidance, 2018) identifies 

dual criteria to assess auditory injury 

(Level A harassment) to five different 

marine mammal groups (based on 

hearing sensitivity) as a result of 

exposure to noise from two different 

types of sources (impulsive or nonimpulsive). The Navy’s planned activity 

includes the use of impulsive (impact 

hammer) and non-impulsive (vibratory 

hammer) sources. 

These thresholds are provided in the 

table 4 below. The references, analysis, 

and methodology used in the 

development of the thresholds are 

described in NMFS’ 2018 Technical 

Guidance, which may be accessed at: 

https://www.fisheries.noaa.gov/ 

national/marine-mammal-protection/ 

marine-mammal-acoustic-technicalguidance. 

TABLE 4—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT

Hearing Group 

PTS Onset Acoustic Thresholds * 

(received level) 

Impulsive Non-impulsive 

Low-Frequency (LF) Cetaceans ...................................... Cell 1: Lpk,flat: 219 dB; LE,LF,24h: 183 dB ......................... Cell 2: LE,LF,24h: 199 dB. 

Mid-Frequency (MF) Cetaceans ...................................... Cell 3: Lpk,flat: 230 dB; LE,MF,24h: 185 dB. ....................... Cell 4: LE,MF,24h: 198 dB. 

High-Frequency (HF) Cetaceans ..................................... Cell 5: Lpk,flat: 202 dB; LE,HF,24h: 155 dB. ....................... Cell 6: LE,HF,24h: 173 dB. 

Phocid Pinnipeds (PW) (Underwater) ............................. Cell 7: Lpk,flat: 218 dB; LE,PW,24h: 185 dB ....................... Cell 8: LE,PW,24h: 201 dB. 


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TABLE 4—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT—Continued 

Hearing Group 

PTS Onset Acoustic Thresholds * 

(received level) 

Impulsive Non-impulsive 

Otariid Pinnipeds (OW) (Underwater) ............................. Cell 9: Lpk,flat: 232 dB; LE,OW,24h: 203 dB ....................... Cell 10: LE,OW,24h: 219 dB. 

* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level thresholds associated with impulsive sounds, these thresholds should 

also be considered. 

Note: Peak sound pressure (Lpk) has a reference value of 1 μPa, and cumulative sound exposure level (LE) has a reference value of 1μPa2s. 

In this table, thresholds are abbreviated to reflect American National Standards Institute standards (ANSI 2013). However, peak sound pressure 

is defined by ANSI as incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ‘‘flat’’ is being 

included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing range. The subscript associated 

with cumulative sound exposure level thresholds indicates the designated marine mammal auditory weighting function (LF, MF, and HF 

cetaceans, and PW and OW pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level 

thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is valuable for 

action proponents to indicate the conditions under which these acoustic thresholds will be exceeded. 

Ensonified Area 

Here, we describe operational and 

environmental parameters of the activity 

that are used in estimating the area 

ensonified above the acoustic 

thresholds, including source levels and 

transmission loss (TL) coefficient. 

Here, we describe operational and 

environmental parameters of the activity 

that are used in estimating the area 

ensonified above the acoustic 

thresholds, including source levels and 

TL coefficient. 

The sound field in the project area is 

the existing background noise plus 

additional construction noise from the 

project. Marine mammals are expected 

to be affected by sound generated by the 

primary components of the project (i.e., 

impact and vibratory pile driving). 

Data from prior pile driving projects 

at the Naval Base Kitsap Bangor and 

Bremerton waterfronts were reviewed in 

the analysis. The representative sound 

pressure levels used in the analysis are 

presented in table 5. 

For vibratory pile driving distances to 

the PTS thresholds, the TL model 

described above incorporated the 

auditory weighting functions for each 

hearing group using a single frequency 

as described in the NMFS Spreadsheet 

(NMFS, 2018). For impact pile driving 

distances to the PTS thresholds for 36- 

inch steel pile and 24-inch concrete 

pile, the TL model described above 

incorporated frequency weighting 

adjustments by applying the auditory 

weighting function over the entire 1- 

second (sound exposure level) SEL 

spectral data sets from impact pile 

driving. If a source level for a particular 

pile size was not available, the next 

highest source level was used to 

produce a conservative estimate of areas 

above threshold values. 

In order to calculate distances to the 

Level A harassment and Level B 

harassment thresholds for the methods 

and piles being used in this project, the 

Navy used acoustic monitoring data 

from various similar locations to 

develop source levels for the different 

pile types, sizes, and methods planned 

for use (table 5). 

TABLE 5—SOURCE LEVELS FOR REMOVAL AND INSTALLATION ACTIVITIES

Pile Diameter 

(inches) 

RMS1

(dB re 1 μPa) 

Peak 1

(dB re 1 μPa) 

SEL 2

(dB re 1 μPa2 sec) 

Impact Installation: 

Concrete ........................................................................................... 24 174 189 167 

Steel Pipe 2 ....................................................................................... 36 192 211 184 

Vibratory Removal: 

Steel Fender ..................................................................................... 14 150 N/A N/A 

Vibratory Installation: 

Steel Fender ..................................................................................... 14 150 N/A N/A 

Composite Fender ............................................................................ 18.75 150 N/A N/A 

Steel pipe .......................................................................................... 36 167 N/A N/A 

Source: Navy, 2015; Navy, 2017, 2018, NAVFAC SW, 2020; WDOT, 2017. 

Key: N/A = not applicable. 

1Sound pressure levels are presented for a distance of 10 m from the pile. RMS and Peak levels are relative to 1 μPa and cumulative SEL 

levels are relative to 1 μPa2 sec. 2Values modeled for impact driving 36-inch steel piles will be reduced by 8 dB for noise exposure modeling to account for attenuation from a 

bubble curtain. 

A bubble curtain will be used to 

minimize the noise generated by impact 

driving of steel pipe piles. Note that 

impact pile driving of steel piles will 

only occur if it is necessary to install the 

36-inch steel piles and none are 

currently planned to be installed. If steel 

piles became necessary then a 

maximum of 2 piles will be installed 

within the 5-year effective period of the 

LOA. The bubble curtain is expected to 

attenuate impact pile driving sound 

levels an average of 8 dB based on past 

performance during similar Navy 

projects in Puget Sound (Navy, 2015); 

therefore, 8 dB was subtracted from 

values in table 5 prior to modeling the 

behavioral and PTS thresholds for 

impact pile driving steel pipe piles. For 

the cumulative SEL PTS thresholds, 

auditory weighting functions were 

applied to the attenuated 1-second SEL 

spectra for steel pipe piles. 

Level B Harassment Zones 

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, 


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source and receiver depth, water depth, 

water chemistry, and bottom 

composition and topography. The 

general formula for underwater TL is: 

TL = B * Log10 (R1/R2), 

where 

TL = transmission loss in dB, 

B = transmission loss coefficient (for 

practical spreading equals 15), 

R1 = the distance of the modeled SPL from 

the driven pile, and 

R2 = the distance from the driven pile of the 

initial measurement. 

The recommended TL coefficient for 

most nearshore environments is the 

practical spreading value of 15. This 

value results in an expected propagation 

environment that would lie between 

spherical and cylindrical spreading loss 

conditions, which is the most 

appropriate assumption for the Navy’s 

activities. The Level B harassment zones 

and areas for the Navy’s activities are 

shown in table 6. 

TABLE 6—CALCULATED RADIAL DISTANCE(S) TO UNDERWATER MARINE MAMMAL VIBRATORY PILE DRIVING NOISE

THRESHOLDS AND AREAS ENCOMPASSED WITHIN THRESHOLD DISTANCE

Type 

Behavioral disturbance— 

Level B harassment 

(120 dB RMS) 

Radial distance 

to threshold 

Area encompassed 

by threshold 

14-inch steel H fender pile (vibratory) .................................................................................................... 1,000 m .................. 1.8 km2. 

18.75-in composite fender pile (vibratory) .............................................................................................. 1,000 m .................. 1.8 km2. 

36-inch steel (vibratory) .......................................................................................................................... 13.6 km .................. 54 km2. 

Level A Harassment Zones 

The ensonified area associated with 

Level A harassment is more technically 

challenging to predict due to the need 

to account for a duration component. 

Therefore, NMFS developed an optional 

User Spreadsheet tool to accompany the 

Technical Guidance that can be used to 

relatively simply predict an isopleth 

distance for use in conjunction with 

marine mammal density or occurrence 

to help predict potential takes. We note 

that because of some of the assumptions 

included in the methods underlying this 

optional tool, we anticipate that the 

resulting isopleth estimates are typically 

going to be overestimates of some 

degree, which may result in an 

overestimate of potential take by Level 

A harassment. However, this optional 

tool offers the best way to estimate 

isopleth distances when more 

sophisticated modeling methods are not 

available or practical. For stationary 

sources such as impact and vibratory 

driving, the optional User Spreadsheet 

tool predicts the distance at which, if a 

marine mammal remained at that 

distance for the duration of the activity, 

it would be expected to incur PTS. 

The isopleths generated by the User 

Spreadsheet used the same TL 

coefficient as the Level B harassment 

zone calculations (i.e., the practical 

spreading value of 15). Inputs used in 

the User Spreadsheet (e.g., number of 

piles per day, duration and/or strikes 

per pile) are presented in table 7. The 

maximum RMS SPL/SEL SPL and 

resulting isopleths are reported below in 

table 8 and table 9. The maximum RMS 

SPL value was used to calculate Level 

A harassment isopleths for vibratory 

pile driving while the single strike SEL 

SPL value was used to calculate Level 

A harassment isopleths for impact pile 

driving activities. Note that Peak PTS 

thresholds were smaller for all pile sizes 

and hearing groups compared to SEL 

SPL values. 

TABLE 7—PARAMETERS OF PILE DRIVING ACTIVITY USED IN USER SPREADSHEET

24-Inch concrete 36-Inch steel Fender pile 

Removal or 

installation 

of steel 

14-inch steel 

or 18.75-inch 

composites 

36-Inch steel 

Type of installation/removal ....................................... Impact ................. Impact ................. Vibratory ........ Vibratory ........ Vibratory. 

Source Level ............................................................. 167 SEL/189 PK 184 SEL/211 PK 144 RMS ....... 150 RMS ........ 192 RMS. 

Weighting Factor Adjustment (kHz) .......................... 2 .......................... 2 .......................... 2.5 ................. 2.5 .................. 2.5. 

(a) Number of strikes/pile .......................................... 1,000 ................... 500.

(a) Activity Duration (min) within 24-h period ............ ............................. ............................. 10 .................. 10 ................... 45. 

Propagation (xLogR) ................................................. 15 ........................ 15 ........................ 15 .................. 15 ................... 15. 

Piles per day ............................................................. 2 .......................... 1 .......................... 2 .................... 2 ..................... 1. 

Distance of source level measurement (meters) ...... 10 ........................ 10 ........................ 10 .................. 10 ................... 10. 

TABLE 8—CALCULATED RADIAL DISTANCE(S) TO IMPACT PILE DRIVING NOISE THRESHOLDS FOR LEVEL A AND LEVEL B 

HARASSMENT AND ASSOCIATED AREAS 1

Level A 

harassment 

pinnipeds 

Level A 

harassment 

cetaceans 

Behavioral disturbance 

Level B (160 dB RMS) 

Harbor seal 

(m) 

Sea lion 

(m) 

LF 

(m) 

MF 

(m) 

HF 

(m) 

Radial distance 

to threshold 

(m) 

Area 

encompassed by 

threshold 

(km2) 

24-inch concrete ........................................................ 29 2 54 2 64 86 0.02 


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TABLE 8—CALCULATED RADIAL DISTANCE(S) TO IMPACT PILE DRIVING NOISE THRESHOLDS FOR LEVEL A AND LEVEL B 

HARASSMENT AND ASSOCIATED AREAS 1—Continued 

Level A 

harassment 

pinnipeds 

Level A 

harassment 

cetaceans 

Behavioral disturbance 

Level B (160 dB RMS) 

Harbor seal 

(m) 

Sea lion 

(m) 

LF 

(m) 

MF 

(m) 

HF 

(m) 

Radial distance 

to threshold 

(m) 

Area 

encompassed by 

threshold 

(km2) 

36-inch steel .............................................................. 182 13 243 8 256 398 0.5 

1 Calculations based on SELCUM threshold criteria shown in Table 4 and source levels shown in Table 5. 

TABLE 9—CALCULATED RADIAL DISTANCE(S) TO VIBRATORY PILE DRIVING NOISE THRESHOLDS FOR LEVEL A AND LEVEL

B HARASSMENT AND ASSOCIATED AREAS 1

Level A 

harassment 

pinnipeds 

Level A 

harassment 

cetaceans 

Behavioral disturbance 

Level B (120 dB RMS) 

Phocids 

(m) 

Otariids 

(m) 

LF 

(m) 

MF 

(m) 

HF 

(m) 

Radial distance 

to threshold 

Area 

encompassed by 

threshold 

(km2) 

14-inch steel H fender pile (vibratory) ...................... <1 <1 <1 <1 <1 1,000 m 1.8 

18.75-in composite fender pile (vibratory ................. <1 <1 <1 <1 <1 1,000 m 1.8 

36-inch steel (Vibratory) ............................................ 4 <1 7 <1 11 13.6 km 54 

1Vibratory pile driving would only occur if it is necessary to install 36 inch steel piles, none are currently planned to be installed. If steel piles became necessary 

then only up to eight would be installed within the 5 years of the LOA. 

Marine Mammal Occurrence and Take 

Calculation and Estimation 

In this section we provide information 

about the occurrence of marine 

mammals, including density or other 

relevant information that will inform 

the take calculations. We describe how 

the information provided above is 

brought together to produce a 

quantitative take estimate for each 

species. 

Take Estimation 

To quantitatively assess potential 

exposure of marine mammals to noise 

levels from pile driving over the NMFS 

threshold guidance, the following 

equation was first used to provide an 

estimate of potential exposures within 

estimated harassment zones: 

Exposure estimate = N × Level B 

harassment zone (km2) × maximum days 

of pile driving per year where N = 

density estimate (animals per km2) used 

for each species. 

Note that the area of the harassment 

zone is truncated by land masses 

surrounding the area (i.e., Whidbey 

Island, Port Townsend mainland, and 

Indian Island). Densities are shown in 

table 10. 

In addition, local occurrence data 

from prior monitoring efforts, discussed 

in the next paragraph, was used as a 

supplement to estimate potential 

occurrence of harbor seals within the 

Level A harassment zones. This method 

is conservative in providing estimates of 

potential exposure above the total given 

using the aforementioned equation that 

we equate here with Level A 

harassment. 

For harbor seals, which were the 

primary species found within 1,000 m 

of the Ammunition Wharf during pile 

driving monitoring from 2014 to 2016 

and 2020 (Navy, 2014, 2016, 2021), a 

daily rate of harbor seal occurrence was 

determined for vibratory installation of 

fender piles for the Level A harassment 

zones. Only harbor seals were observed 

during pile driving monitoring (Navy, 

2016, 2020) and weekly marine mammal 

surveys (2022) at NAVMAG Indian 

Island Ammunition Wharf with the 

exception of a single harbor porpoise 

and a single California sea lion. The 

site-specific data was used to estimate 

take only for harbor seals at a rate of 0.5 

seals per day from concrete impact 

driving and eight seals per day from 

steel impact driving, based on the 

different estimated zone sizes. 

During the site-specific monitoring 

efforts discussed above, only harbor 

seals were observed during pile driving 

monitoring (Navy, 2016, 2020) and 

weekly marine mammal surveys (2022) 

at NAVMAG Indian Island Ammunition 

Wharf, with the exception of a single 

harbor porpoise and a single California 

sea lion. For species other than harbor 

seal—for which use of the available 

density information and the equation 

given above provide low calculated take 

estimates (described in species-specific 

sections below)—it was assumed 

between one (i.e., gray whale, minke 

whale) and three animals will be taken 

over the duration of the rule (by Level 

B harassment only). For California sea 

lions, Steller sea lions, and northern 

elephant seals it was assumed that there 

will be one take per year from concrete/ 

fender pile installation (by Level B 

harassment only). It was also assumed 

that there will be one additional take 

per year by Level B harassment during 

steel pile installation for the northern 

elephant seal. In contrast to pinniped 

species, Dall’s porpoises and harbor 

porpoises often occur in pods of two to 

four porpoises. Therefore, it was 

assumed that there will be up to three 

takes per year by concrete/fender pile 

installation for each species with three 

additional takes per year only for Dall’s 

porpoises per year due to steel pile 

installation. All takes are assumed to be 

by Level B harassment only, based on 

the assumed rarity of occurrence and 

the Navy’s plan to implement shutdown 

procedures for all cetaceans at the 

estimated Level B harassment distance. 

The density estimates given in table 

10 come from the Pacific Navy’s Marine 

Species Density Database (NMSDD), 

Naval Facilities Engineering Systems 

Command (NAVFAC) Pacific Technical 

Report (Navy, 2020) and Smultea et al. 

(2017) (for harbor porpoise). The 

seasonal density value for each species 

during the in-water work window at 

each site was used in the marine 

mammal take assessment calculation. 

Note that the largest Level B 

harassment zone will be generated 

during vibratory driving. The Level B 

harassment zone for an impact hammer 

will be encompassed by the larger Level 

B harassment zone from the vibratory 

driver. Impact pile driving was assumed 


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to be one pile per day but actual daily 

production rates may be higher with a 

maximum of two per day, resulting in 

fewer in-water pile driving days. It was 

assumed that 22 days of concrete pile 

installation will occur. This is a 

conservative estimate based on past 

work at NAVMAG. There will be up to 

22 concrete piles (24-in) driven over the 

maximum of 22 days per year over 5 

years with up to two 24-inch concrete 

piles driven per day (1 to 2 piles 

installed per day; mean of 1.8 piles 

installed per day) depending on 

accessing the wharf deck, weather, 

harbor seal delays, or equipment issues. 

Note that this conservative estimate of 

pile driving days is used solely to assess 

the number of days during which pile 

driving could occur if production was 

delayed due to equipment failure, 

safety, etc. In a real construction 

situation, pile driving production rates 

will be maximized when possible. 

TABLE 10—MARINE MAMMAL SPECIES DENSITIES IN PROJECT AREA

Species Region location Density (October–February) * 

Animals km2

Gray whale ................................ North Puget Sound ................. Zero (within 1,000 m).1

0.00048 (Fall and Winter).2

Minke Whale ............................. Puget Sound ........................... Zero (within 1,000 m).1

0.00045 (Annual).2

Harbor porpoise ........................ North Puget Sound ................. 1.16 (Annual).2 3

Dall’s porpoise .......................... Puget Sound ........................... 0.00045 (Annual).2

Steller sea lion .......................... Puget Sound ........................... Zero (within 1,000 m).2

0.0478 (Fall and Winter).1

California sea lion ..................... Puget Sound ........................... Zero (within 1,000 m).1

0.2211 (Fall).2

0.1100 (Winter).2

Northern elephant seal ............. Puget Sound ........................... Zero (within 1,000 m).1

0.0000 (Annual).2

Harbor Seal ............................... North Puget Sound ................. 14–18.75-inch Fender Pile Driving.1

Within 10 m = 0.0 seals/day (Level A zone). 

Within 1,000 m = 15.54 seals per day (Level B harassment zone). 

24-inch Concrete Impact Pile Driving.1

Within 29 m = 0.5 seals/day (Level A harassment zone). 

Combine with the larger fender pile vibratory Level B harassment zone. 

36-inch Steel Impact Pile Driving.1

Within 182 m = 8 seals/day (Level A harassment zone). 

Combine with the larger vibratory zone for Level B harassment. 

36-inch Steel Vibratory Pile Driving. 

Within 10 m = 0.0 seals/day (Level A zone). 

Within 13.6 km (54 km2) = 2.83 seals/km2. 

* 13.6 km with an area of 54 km2 (a large part of the area was truncated by land masses) was used for 36-inch steel pile vibratory installation. 

Sources: 1 Navy, 2014, 2016; 2021; 2 NMSDD (Navy, 2020), 3Smultea et al. (2017). 

It is important to note that the 

successful implementation of mitigation 

methods (i.e., visual monitoring and the 

use of shutdown zones) is expected to 

result in no Level A harassment 

exposure to all marine mammals except 

harbor seals because the injury zones 

and behavioral zones will be monitored 

during pile driving. Harbor seal Level A 

harassment exposure will be limited to 

the smallest extent practicable. The 

exposure assessment estimates the 

numbers of individuals potentially 

exposed to the effects of pile driving 

noise exceeding NMFS established 

thresholds. Results from acoustic impact 

exposure assessments should be 

regarded as conservative overestimates 

that are strongly influenced by limited 

marine mammal data, the assumption 

that marine mammals will be present 

during pile driving, and the 

assumptions that the maximum number 

of piles will be extracted or installed. 

Gray Whale 

Most gray whales in Puget Sound 

utilize the feeding areas in northern 

Puget Sound around Whidbey Island 

and in Port Susan in March through 

June with a few individual sightings 

occurring year-round that are not always 

associated with feeding areas. Therefore, 

gray whales are included in the take 

authorization. The majority of in-water 

work will occur during the fall and 

winter when gray whales are less likely 

to be present in Puget Sound. Therefore, 

based on a low probability of occurrence 

within the vibratory harassment zones, 

the Navy used the formula described 

above to calculate estimated exposures. 

The formula estimated zero takes per 

year; however, due to the uncertainty of 

gray whale movements and the large 

area of exposure during vibratory 

driving of 36-inch steel piles, the Navy 

has requested and NMFS has assumed 

take by Level B harassment at a rate of 

one animal per year. 

To protect gray whales from noise 

impacts, the Navy will implement a 

shutdown if protected species observers 

(PSO) see gray whales approaching or 

within any harassment zone. A PSO will 

be stationed at locations from which the 

injury zone and behavioral zone for 

impact and vibratory pile driving are 

visible and will implement shutdown if 

a whale approaches or enters either 

zone. With the implementation of 

monitoring, even if a whale enters an 

injury zone, shutdown would occur 

before cumulative exposure to noise 

levels that would result in PTS could 

occur. Because pile driving will be shut 

down if whales are in the injury zone, 

no Level A harassment take has been 

requested or authorized by NMFS. In 

summary, the Navy has requested, and 

NMFS has authorized one take of gray 

whale by Level B harassment each year 

for the duration of the 5-year LOA. 

Minke Whale 

Minke whales in Washington inland 

waters typically feed in the areas around 

the San Juan Islands and along banks in 

the Strait of Juan de Fuca. Minke whales 

are infrequent visitors to Puget Sound, 

especially east of Admiralty Inlet. When 

present, minke whales are usually seen 

singly or in pairs. Therefore, based on 

a low probability of occurrence within 


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the vibratory harassment zones, the 

Navy used the same equation discussed 

above to calculate estimated exposures. 

The formula estimated zero takes 

annually for the duration of the LOA. 

However, due to the uncertainty of 

minke whale movements and the large 

area of exposure during vibratory 

driving of 36-inch steel piles, the Navy 

requested, and NMFS has authorized 

take for the exposure of one minke 

whale per year for the duration of the 

5-year LOA. 

To protect minke whales from noise 

impacts, the Navy will implement a 

shutdown if PSOs see minke whales 

approaching or within any harassment 

zone. A PSO will be stationed at 

locations from which the injury zone 

and behavioral zone for impact and 

vibratory pile driving are visible and 

will implement shutdown if a whale 

approaches or enters either zone. PSOs 

may be stationed on boats to observe a 

greater portion of the shutdown zone 

than is visible from land-based 

locations. With the implementation of 

monitoring, even if a whale enters an 

injury zone, shutdown would occur 

before cumulative exposure to noise 

levels that would result in PTS could 

occur. Because pile driving will be shut 

down if whales are in the injury zone, 

no Level A harassment take has been 

requested or will be authorized by 

NMFS. In summary, although minke 

whales are rare in the project area, the 

Navy has requested and NMFS has 

assumed one take of minke whale by 

Level B harassment each year for the 

duration of the 5-year LOA. 

Dall’s Porpoise 

Dall’s porpoises are most abundant in 

the Strait of Juan de Fuca and Haro 

Strait in the San Juan Islands area, but 

may be present in Puget Sound yearround. Group size is usually two to four, 

although larger groups are often sighted 

(Anderson et al., 2018). In Puget Sound, 

the Navy has estimated that Dall’s 

porpoise density is 0.045 animals/km2, 

although they have not been reported 

near NAVMAG Indian Island in recent 

years and their occurrence in both the 

Salish Sea and Puget Sound appears to 

be declining (Smultea et al., 2015; 

Evenson et al., 2016; Jefferson et al., 

2016). The Navy used the formula 

described previously to calculate 

potential exposures. The formula 

estimated zero takes. Due to the 

uncertainty of Dall’s porpoise 

movements and the large estimated 

harassment area during vibratory 

driving, the Navy assumed, and NMFS 

concurred, that there will be three takes 

from work on the fender piles and three 

takes from work on the steel piles each 

year, by Level B harassment only. 

To protect Dall’s porpoises from noise 

impacts, the Navy will implement a 

shutdown if PSOs see porpoises 

approaching or inside of any harassment 

zone. A PSO will be stationed at 

locations from which the harassment 

zones for impact and vibratory pile 

driving are visible and will implement 

shutdown if a porpoise approaches or 

enters any zone. With the 

implementation of monitoring, even if a 

Dall’s porpoise enters an injury zone, 

shutdown would occur before 

cumulative exposure to noise levels that 

would result in PTS could occur. 

Because pile driving will be shut down 

if porpoises are in the injury zone, no 

Level A harassment take has been 

requested or will be authorized. In 

summary, although Dall’s porpoises are 

rare in the project area, the Navy has 

requested, and NMFS has assumed take 

of 30 Dall’s porpoises (6 per year) by 

Level B harassment over the 5-year LOA 

period. 

Harbor Porpoise 

Harbor porpoises may be present in 

all major regions of Puget Sound 

throughout the year. Group sizes 

ranging from 1 to 150 individuals were 

reported in aerial surveys conducted 

from summer 2013 to spring 2016, but 

mean group size was 1.7 animals 

(Smultea et al., 2017). The estimated 

harbor porpoise density in inland 

waters is provided in table 10. The 

estimated exposure equation described 

previously was employed resulting in 

125 takes per year from steel vibratory 

driving. Take from concrete/fender 

vibratory driving was calculated to be 

0.05 exposures per year. However, the 

Navy requested authorization of three 

takes per year resulting from this 

activity as a precaution. Note that 

harbor porpoises were not observed 

during pile driving monitoring at 

NAVMAG Indian Island ammunition 

wharf from 2014 to 2016 (Navy, 2014; 

Navy 2016), but one was observed in 

2020 within 200 m of the Wharf (Navy, 

2021). 

The Navy will implement a shutdown 

if porpoises are seen by PSOs entering 

or within any harassment zone in order 

to protect harbor porpoises from noise 

impacts. A monitor will be stationed at 

locations from which the injury and 

behavioral harassment zones for impact 

and vibratory pile driving are visible 

and will implement shutdown if a 

porpoise approaches or enters any 

harassment zone. With the 

implementation of monitoring, even if a 

harbor porpoise enters an injury zone, 

shutdown would occur before 

cumulative exposure to noise levels that 

would result in PTS could occur. 

Because pile driving will be shut down 

if porpoises are in the injury zone, no 

Level A harassment take has been 

requested or will be authorized. In 

summary, the Navy has requested, and 

NMFS has assumed take of up to 640 

harbor porpoises by Level B harassment 

(3 per year for work on concrete/fender 

piles and 125 per year from for work on 

steel piles) for the duration of the 5-year 

LOA. 

California Sea Lion 

California sea lions occur in Puget 

Sound from approximately August to 

June. This species occasionally hauls 

out on the port security barriers at 

NAVMAG Indian Island. These haulouts 

are adjacent to, in, or near the Level B 

harassment zones, so exposure may 

occur if animals move through Level B 

harassment zones during impact or 

vibratory pile driving activities. 

California sea lions were not observed 

during previous pile driving monitoring 

at NAVMAG Indian Island ammunition 

wharf in 2014 to 2016 (Navy, 2014; 

Navy 2016), but one was observed 

during 2020 (Navy, 2021). Although 

calculated take was zero, reflecting their 

unlikely occurrence, Level B harassment 

exposures for the concrete and fender 

pile driving were estimated as one sea 

lion per year. Exposure estimates for 

vibratory driving of steel piles utilized 

the estimated exposure equation, 

resulting in estimated take of 17.88 sea 

lions per year, which was rounded up 

to 18 sea lion takes per year. Because a 

Level A harassment injury zone can be 

effectively monitored and a shutdown 

zone will be implemented, no take by 

Level A harassment is anticipated or 

will be authorized. Based on the 

aforementioned considerations, NMFS 

is authorizing take of 95 California sea 

lions (1 per year by work on concrete/ 

fender piles and 18 per year from work 

on steel piles), by Level B harassment 

only, for the duration of the 5-year LOA. 

Steller Sea Lion 

Steller sea lions occur seasonally in 

Puget Sound primarily from September 

through May. Take may occur if these 

animals move through Level B 

harassment zones during impact or 

vibratory pile driving. Although their 

occurrence is unlikely, the Navy 

assumed that there will be one Level B 

harassment take from concrete and 

fender pile driving per year. Level B 

harassment exposure estimates for steel 

piles utilized the exposure estimate 

equation described previously using 

densities from table 10 resulting in an 

estimated take of 5.16 animals per year 


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rounded to 5 takes. Steller sea lions 

were not observed during previous 

monitoring at NAVMAG Indian Island 

ammunition wharf in 2014 to 2016 

(Navy, 2014, 2016, 2021). Because the 

Level A harassment injury zone is small 

under all driving scenarios, it can be 

effectively monitored. A shutdown will 

be implemented if animals approach the 

injury zone and no exposure to Level A 

harassment noise levels is anticipated at 

any location. In summary, the Navy has 

requested, and NMFS is authorizing 

take of up to 30 Steller sea lions (five 

for work on concrete/fender piles over 

5 years and 25 for work on steel piles 

over 5 years) by Level B harassment for 

the duration of the 5-year LOA. 

Northern Elephant Seal 

Northern elephant seals are 

considered rare visitors to Puget Sound. 

No regular elephant seal haul outs occur 

in Puget Sound, although individual 

elephant seals have been detected 

hauling out for 2 to 4 weeks to molt, 

usually during the spring and summer. 

Haul out locations are unpredictable, 

but only one record is known for a Navy 

installation. The Navy reports a density 

of 0.0 in Puget Sound (Navy, 2020). 

However, because there are occasional 

sightings in Puget Sound, the Navy 

assumed that there will be one exposure 

from concrete/fender driving and one 

exposure from steel driving during each 

year of the LOA. Because elephant seals 

are rare in the project area and 

monitoring and shutdown measures will 

be implemented, no Level A harassment 

exposure is anticipated. In summary, 

the Navy has requested, and NMFS is 

authorizing take of up to 10 northern 

elephant seals (2 per year) by Level B 

harassment for the duration of the 5- 

year LOA. 

Pacific Harbor Seal 

Pacific harbor seals are expected to 

occur year-round at NAVMAG Indian 

Island. This species hauls out regularly 

at Rat Island adjacent to the 

northeastern end of NAVMAG Indian 

Island year-round with a dip in numbers 

in winter months. Harbor seals are most 

likely to be exposed to Level A 

harassment noise when they swim 

through the area near the Ammunition 

Wharf during impact pile driving (182 

m for steel impact driving and 29 m for 

concrete impact driving). Pile driving 

will shut down whenever a seal is 

detected by monitors nearing or within 

the injury zone, but harbor seals can 

dive for up to 15 minutes and may not 

be detected until they have been within 

the injury zone for a sufficient period of 

time to incur PTS. For most pile driving 

activities, exposure of harbor seals to 

pile driving noise will be limited to 

Level B harassment. Level B harassment 

exposure estimates for vibratory driving 

were determined using the formula of 

Level B harassment zone area × density 

× days of vibratory pile driving. The 

Navy has calculated take by Level B 

harassment of 1,710 harbor seals during 

vibratory installation of fender piles 

(342 per year), and 1,530 harbor seals 

during vibratory pile driving of steel 

piles (306 per year). Therefore, the Navy 

has requested, and NMFS is authorizing 

take of up to 3,240 Pacific harbor seals 

by Level B harassment for the duration 

of the LOA. In addition, the Navy has 

requested and NMFS is authorizing up 

to 135 harbor seal takes (27 per year) by 

Level A harassment during the 5-year 

LOA. This is based on the daily average 

of site-specific observations from several 

seasons of pile driving monitoring at the 

Ammunition Wharf and weekly surveys 

conducted at NAVMAG Indian Island 

provided above. Observations of seals 

within 29 m would be calculated to a 

mean of seals per day within the Level 

A harassment zone. (Using the density 

value would underestimate the number 

of seals in that small zone.) This 

assumption results in 11 Level A 

harassment takes per year (0.5 seals/day 

for 22 days) for impact driving of 

concrete piles (55 takes for 5 years) and 

16 takes per year (8 seals/day for 2 days) 

for impact driving of steel piles (80 

takes over 5 years). 

The annual and total number of takes 

that may be authorized by NMFS are 

shown in table 11 and table 12. 

TABLE 11—ANNUAL TAKE BY LEVEL A AND LEVEL B HARASSMENT AND PERCENTAGE OF STOCK ABUNDANCE FOR

AUTHORIZED SPECIES/STOCKS

Species 

Exposures 

24-Inch concrete piles and/or 

14-in/18.75-inch fender piles (up 

to 22 piles/year) 

36-Inch steel piles (up to 2 

piles/year) 

Total annual Population 

Percent of 

stock/distinct 

population 

segment 

(DPS) per 

year 

Level B impact 

or 

vibratory 

Level A 

impact 

Level B impact 

or 

vibratory 

Level A 

impact 

Gray Whale ................................................... 0 0 1 0 1 26,960 <0.01 

Minke Whale ................................................. 0 0 1 0 1 915 <0.01 

Dall’s Porpoise .............................................. 3 0 3 0 6 16,498 <0.01 

Harbor Porpoise ............................................ 3 0 125 0 128 11,233 1.11 

California Sea Lion ........................................ 1 0 18 0 19 257,606 <0.01 

Steller Sea Lion ............................................. 1 0 5 0 6 43,201 <0.01 

Northern Elephant Seal ................................. 1 0 1 0 2 187,386 <0.01 

Pacific Harbor Seal ....................................... 342 11 306 16 675 11,036 6.11 

TABLE 12—TOTAL 5-YEAR AUTHORIZED TAKES (LEVEL A HARASSMENT AND LEVEL B HARASSMENT) 

Species Stock Level A 

harassment 

Level B 

harassment Total 5-year 

Gray Whale ...................................... Eastern North Pacific .................................................... ........................ 5 5 

Minke Whale .................................... California/Oregon/Washington ...................................... ........................ 5 5 

Dall’s Porpoise ................................. California/Oregon/Washington ...................................... ........................ 30 30 

Harbor Porpoise ............................... Washington Inland Waters ............................................ ........................ 640 640 

California Sea Lion ........................... United States ................................................................ ........................ 95 95 

Steller Sea Lion ................................ Eastern United States ................................................... ........................ 30 30 

Northern Elephant Seal .................... California Breeding ....................................................... ........................ 10 10 

Pacific Harbor Seal .......................... Washington Northern Inland Waters ............................ 135 3,240 3,375 


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Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 5687 

Mitigation 

In order to issue an LOA under 

section 101(a)(5)(A) of the MMPA, 

NMFS must set forth the permissible 

methods of taking pursuant to the 

activity, and other means of effecting 

the least practicable impact on the 

species or stock and its habitat, paying 

particular attention to rookeries, mating 

grounds, and areas of similar 

significance, and on the availability of 

the species or stock for taking for certain 

subsistence uses (latter not applicable 

for this action). NMFS regulations 

require applicants for incidental take 

authorizations to include information 

about the availability and feasibility 

(economic and technological) of 

equipment, methods, and manner of 

conducting the activity or other means 

of effecting the least practicable adverse 

impact upon the affected species or 

stocks, and their habitat (50 CFR 

216.104(a)(11)). 

In evaluating how mitigation may or 

may not be appropriate to ensure the 

least practicable adverse impact on 

species or stocks and their habitat, as 

well as subsistence uses where 

applicable, NMFS considers two 

primary factors: 

(1) The manner in which, and the 

degree to which, the successful 

implementation of the measure(s) is 

expected to reduce impacts to marine 

mammals, marine mammal species or 

stocks, and their habitat. This considers 

the nature of the potential adverse 

impact being mitigated (likelihood, 

scope, range). It further considers the 

likelihood that the measure will be 

effective if implemented (probability of 

accomplishing the mitigating result if 

implemented as planned), the 

likelihood of effective implementation 

(probability implemented as planned), 

and; 

(2) The practicability of the measures 

for applicant implementation, which 

may consider such things as cost and 

impact on operations. 

In order to limit impacts to marine 

mammals, vibratory installation will be 

used by the Navy to the extent 

practicable to drive steel piles to 

minimize high sound pressure levels 

associated with impact pile driving. 

Jetting will also be used to the extent 

possible to install concrete piles in 

order to minimize higher sound 

pressure levels associated with impact 

pile driving. Note that a draft 

monitoring plan will be submitted in 

the spring at least 90 days prior to the 

start of the in-water work period 

(October) during the first year of the 

project (2024). The final monitoring 

plan will be prepared and submitted to 

NMFS within 30 days following receipt 

of comments on the draft plan from 

NMFS. 

The Navy will ensure that 

construction supervisors and crews, the 

monitoring team, and relevant Navy 

staff are trained and prior to the start of 

construction activity subject to this rule, 

so that responsibilities, communication 

procedures, monitoring protocols, and 

operational procedures are clearly 

understood. New personnel joining 

during the project will be trained prior 

to commencing work. 

Shutdown Zones 

Before the commencement of in-water 

construction activities, the Navy will 

establish shutdown zones for all impact 

and pile driving activities. The purpose 

of a shutdown zone is generally to 

define an area within which shutdown 

of the activity would occur upon 

sighting of a marine mammal (or in 

anticipation of an animal entering the 

defined area). Shutdown zones will vary 

based on the activity type and marine 

mammal hearing group but will include 

all areas where the underwater sound 

pressure levels are anticipated to equal 

or exceed the Level A harassment 

(injury) criteria for marine mammals. 

The shutdown zone will always be a 

minimum of 10 m to prevent injury 

from physical interaction of marine 

mammals with construction equipment. 

The Level A harassment zones are based 

on the maximum calculated radius for 

pinnipeds and cetaceans, specifically 

harbor porpoises, during installation of 

36-inch steel piles and 24-inch concrete 

piles with impact techniques, and the 

Level B harassment zone for impact and 

vibratory pile installation. 

Injury to harbor seals from noise due 

to impact and vibratory pile driving and 

physical interaction with construction 

equipment will be minimized to the 

extent practicable by implementing a 

shutdown if the animals are observed to 

be swimming towards the injury zone. 

For steel pile impact driving, to the 

extent possible, PSOs will initiate 

shutdown when harbor seals enter the 

injury zone; however, because of the 

size of the zone and the inherent 

difficulty in monitoring harbor seals, a 

highly mobile species, it may not be 

practical, which is why Level A 

harassment take has been analyzed. 

The taking by serious injury or death 

of any of the species listed in table 12 

or any taking of any other species of 

marine mammal is prohibited. The Navy 

will establish shutdown zones for all 

marine mammals for which incidental 

take has been authorized but the 

authorized number of takes has been 

met. These zones are equivalent to the 

Level B harassment zones for each 

activity. If such animals are sighted 

within the vicinity of the project areas 

and are approaching the Level B 

harassment zone, the Navy will shut 

down the pile driving equipment to 

avoid possible take of these species. 

Pile driving activities will cease if any 

cetaceans authorized for take are seen 

approaching or entering any harassment 

zone. Work will be halted and delayed 

until either the animal has voluntarily 

left and been visually confirmed beyond 

the injury zone or visual portion of the 

Level B harassment zone or 15 minutes 

have passed without re-detection of the 

animal. Additionally, if a shutdown 

zone is obscured by fog or poor lighting 

conditions, pile driving will not be 

initiated until the entire shutdown zone 

is visible. 

If a pinniped approaches or enters a 

shutdown zone during pile impact or 

vibratory driving, work will 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 redetection of the animal. If a pinniped is 

observed in the Level B harassment 

zone, but not approaching or entering 

the shutdown zone, the work will be 

allowed to proceed without cessation of 

pile driving. Marine mammal behavior 

will be monitored and documented. 

TABLE 13—SHUTDOWN AND HARASSMENT ZONES

Pile size and type 

Shutdown zone 

(m) Level B 

harassment zone 

(m) Cetaceans Harbor seal Sea lion 

24-inch Concrete Impact ......................................................................... 90 30 10 90 

36-inch Steel Impact ................................................................................ 400 200 20 400 

36-inch Steel Vibratory ............................................................................ 13,600 10 10 13,600 


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TABLE 13—SHUTDOWN AND HARASSMENT ZONES—Continued 

Pile size and type 

Shutdown zone 

(m) Level B 

harassment zone 

(m) Cetaceans Harbor seal Sea lion 

Fender Vibratory ...................................................................................... 1,000 10 10 1,000 

At minimum, the shutdown zone for 

all hearing groups and all activities will 

be 10 m. For in-water heavy machinery 

work other than pile driving (e.g., 

standard barges, etc.), if a marine 

mammal comes within 10 m, operations 

will cease and vessels will reduce speed 

to the minimum level required to 

maintain steerage and safe working 

conditions. This type of work could 

include, for example, the movement of 

the barge to the pile location or 

positioning of the pile on the substrate 

via a crane. 

Pre-Activity Monitoring 

Prior to the start of daily in-water 

construction activity, or whenever a 

break in pile driving of 30 minutes or 

longer occurs, PSOs will observe the 

shutdown and Level B harassment 

zones for a period of 30 minutes. The 

shutdown zone will be considered 

cleared when a marine mammal has not 

been observed within the zone for that 

30-minute period. If a marine mammal 

is observed within the shutdown zones 

listed in table 13, pile driving activity 

would be delayed or halted. If pile 

driving is delayed or halted due to the 

presence of a marine mammal, the 

activity will not commence or resume 

until either the animal has voluntarily 

exited and been visually confirmed 

beyond the shutdown zones or 15 

minutes have passed without redetection of the animal. If work ceases 

for more than 30 minutes, the preactivity monitoring of the shutdown 

zones will commence. A determination 

that the shutdown zone is clear must be 

made during a period of good visibility 

(i.e., the entire shutdown zone and 

surrounding waters must be visible to 

the naked eye). 

Monitoring will take place from 30 

minutes prior to initiation through 30 

minutes post-completion of pile driving. 

Prior to the start of pile driving, the 

shutdown zone will be monitored for 30 

minutes to ensure that the shutdown 

zone is clear of marine mammals. Pile 

driving will only commence once PSOs 

have declared the shutdown zone clear 

of marine mammals. 

Soft Start 

Soft-start procedures are used to 

provide additional protection to marine 

mammals by providing warning and/or 

giving marine mammals a chance to 

leave the area prior to the hammer 

operating at full capacity. For impact 

pile driving, contractors will be required 

to provide an initial set of three strikes 

from the hammer at reduced energy, 

followed by a 30-second waiting period, 

then two subsequent reduced-energy 

strike sets. Soft start will be 

implemented at the start of each day’s 

impact pile driving and at any time 

following cessation of impact pile 

driving for a period of 30 minutes or 

longer. 

Bubble Curtain 

Should use of 36-inch steel piles be 

necessary, a bubble curtain will be used 

for all impact driving of steel piles to 

attenuate noise. Because of the 

relatively low underwater noise levels 

associated with impact driving of 

concrete piles, bubble curtains are not 

required for impact installation of 

concrete piles. 

A bubble curtain will be employed 

during impact installation or proofing of 

steel pile where water depths are greater 

than 0.67 m. A noise attenuation device 

will not be required during vibratory 

pile driving. If a bubble curtain or 

similar measure is used, it will 

distribute air bubbles around 100 

percent of the piling perimeter for the 

full depth of the water column. A 

bubble curtain is usually a ring or series 

of stacked rings that are placed around 

a pile along the pile’s entire length 

under water. The rings are made of 

tubing which has small puncture holes 

through which compressed air is 

pumped. As the compressed air bubbles 

flow from the tubing, they create an air 

barrier that impedes the sound 

produced during pile driving. Any other 

attenuation measure will be required to 

provide 100 percent coverage in the 

water column for the full depth of the 

pile. The lowest bubble ring would be 

in contact with the mudline for the full 

circumference of the ring. The weights 

attached to the bottom ring will ensure 

100 percent mudline contact. No parts 

of the ring or other objects will prevent 

full mudline contact. 

NMFS has determined that the 

required mitigation measures provide 

the means of effecting the least 

practicable adverse impact on the 

affected species or stocks and their 

habitat, paying particular attention to 

rookeries, mating grounds, and areas of 

similar significance. 

Monitoring and Reporting 

In order to issue an LOA for an 

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

MMPA states that NMFS must set forth 

requirements pertaining to the 

monitoring and reporting of such taking. 

The MMPA implementing regulations at 

50 CFR 216.104(a)(13) indicate that 

requests for authorizations must include 

the suggested means of accomplishing 

the necessary monitoring and reporting 

that will result in increased knowledge 

of the species and of the level of taking 

or impacts on populations of marine 

mammals that are expected to be 

present while conducting the activities. 

Effective reporting is critical both to 

compliance as well as ensuring that the 

most value is obtained from the required 

monitoring. 

Monitoring and reporting 

requirements prescribed by NMFS 

should contribute to improved 

understanding of one or more of the 

following: 

• Occurrence of marine mammal 

species or stocks in the area in which 

take is anticipated (e.g., presence, 

abundance, distribution, density); 

• Nature, scope, or context of likely 

marine mammal exposure to potential 

stressors/impacts (individual or 

cumulative, acute or chronic), through 

better understanding of: (1) action or 

environment (e.g., source 

characterization, propagation, ambient 

noise); (2) affected species (e.g., life 

history, dive patterns); (3) co-occurrence 

of marine mammal species with the 

activity; or (4) biological or behavioral 

context of exposure (e.g., age, calving or 

feeding areas); 

• Individual marine mammal 

responses (behavioral or physiological) 

to acoustic stressors (acute, chronic, or 

cumulative), other stressors, or 

cumulative impacts from multiple 

stressors; 

• How anticipated responses to 

stressors impact either: (1) long-term 

fitness and survival of individual 

marine mammals; or (2) populations, 

species, or stocks; 


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• Effects on marine mammal habitat 

(e.g., marine mammal prey species, 

acoustic habitat, or other important 

physical components of marine 

mammal habitat); and, 

• Mitigation and monitoring 

effectiveness. 

The Navy will submit a Marine 

Mammal Monitoring Plan to NMFS for 

approval at least 90 days in advance of 

the start of the first year of construction. 

Visual Monitoring 

• Monitoring must be conducted 

during pile driving activities by 

qualified, NMFS-approved PSOs, in 

accordance with the following 

conditions: PSOs must be independent 

of the activity contractor (for example, 

employed by a subcontractor) and have 

no other assigned tasks during 

monitoring periods. 

• At least one PSO must have prior 

experience performing the duties of a 

PSO during construction activity 

pursuant to a NMFS-issued incidental 

take authorization. 

• Other PSOs may substitute other 

relevant experience, education (degree 

in biological science or related field), or 

training for prior experience performing 

the duties of a PSO during construction 

activity pursuant to a NMFS-issued 

incidental take authorization. 

• Where a team of three or more PSOs 

is required, a lead PSO or monitoring 

coordinator must be designated. The 

lead PSO must have prior experience 

performing the duties of a PSO during 

construction activity pursuant to a 

NMFS-issued incidental take 

authorization. 

• PSOs must be approved by NMFS 

prior to beginning any activity subject to 

this rule. 

All PSOs shall be trained in marine 

mammal identification and behaviors, 

and satisfy the following criteria: 

• Visual acuity in both eyes 

(correction is permissible) sufficient to 

discern moving targets at the water’s 

surface with ability to estimate target 

size and distance. Use of binoculars or 

spotting scope may be necessary to 

correctly identify the target. 

• Advanced education in biological 

science, wildlife management, 

mammalogy or related field (Bachelor’s 

degree or higher is preferred). 

• 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 

(cetaceans and pinnipeds). 

• Sufficient training, orientation or 

experience with vessel operation and 

pile driving operations to provide for 

personal safety during observations. 

• Writing skills sufficient to prepare a 

report of observations. Reports should 

include such information as the 

number, type, and location of marine 

mammals observed; the behavior of 

marine mammals in the area of potential 

sound effects during construction; dates 

and times when observations and inwater construction activities were 

conducted; dates and times when inwater construction activities were 

suspended because of marine mammals, 

etc. 

• Ability to communicate orally, by 

radio or in person, with project 

personnel to provide real time 

information on marine mammals 

observed in the area and necessary 

actions, as needed. 

During pile driving activities, the 

Navy will assign PSOs to monitor the 

identified harassment zones. The 

number and placement of PSOs will 

vary depending upon the pile size, 

location, and number of piles being 

installed or removed. In order to 

effectively monitor the shutdown and 

Level B harassment zones, PSOs will be 

positioned at the best practicable 

vantage points, taking into 

consideration security, safety, and space 

limitations. The PSOs will be stationed 

on the pier, vessel, on shore, or on the 

pile driving barge in a location that will 

provide adequate visual coverage for the 

identified harassment zones. During pile 

driving, at least one PSO will be 

stationed on a vessel if practicable. 

Monitoring will be conducted 30 

minutes before, during, and 30 minutes 

after all in water construction activities. 

In addition, PSOs will record all 

incidents of marine mammal 

occurrence, regardless of distance from 

activity, and will document any 

behavioral reactions in concert with 

distance from piles being driven or 

removed. 

Reporting 

The Navy must submit a draft 

monitoring report to NMFS within 90 

calendar days of the completion of each 

construction year. A draft 

comprehensive 5-year summary report 

must also be submitted to NMFS within 

90 days of the end of the project. The 

reports must detail the monitoring 

protocol and summarize the data 

recorded during monitoring. Final 

annual reports and the final 

comprehensive report must be prepared 

and submitted within 30 days following 

resolution of any NMFS comments on 

the draft report. If no comments are 

received from NMFS within 30 days of 

receipt of the draft report, the report 

must be considered final. If comments 

are received, a final report addressing 

NMFS comments must be submitted 

within 30 days after receipt of 

comments. The marine mammal report 

will include an overall description of 

work completed, a narrative regarding 

marine mammal sightings, and 

associated PSO data sheets. Specifically, 

the report will include: 

• Dates and times (begin and end) of 

all marine mammal monitoring; 

• Construction activities occurring 

during each daily observation period, 

including: (a) How many and what type 

of piles were driven or removed and the 

method (i.e., impact or vibratory); and 

(b) the total duration of time for each 

pile (vibratory driving) number of 

strikes for each pile (impact driving); 

• PSO locations during marine 

mammal monitoring; and 

• Environmental conditions during 

monitoring periods (at beginning and 

end of PSO shift and whenever 

conditions change significantly), 

including Beaufort sea state and any 

other relevant weather conditions 

including cloud cover, fog, sun glare, 

and overall visibility to the horizon, and 

estimated observable distance. 

In addition, for each observation of a 

marine mammal, the marine mammal 

report will include the following 

information: 

• Name of PSO who sighted the 

animal(s) and PSO location and activity 

at time of sighting; 

• Time of sighting; 

• Identification of the animal(s) (e.g., 

genus/species, lowest possible 

taxonomic level, or unidentified), PSO 

confidence in identification, and the 

composition of the group if there is a 

mix of species; 

• Distance and location of each 

observed marine mammal relative to the 

pile being driven for each sighting; 

• Estimated number of animals (min/ 

max/best estimate); 

• Estimated number of animals by 

cohort (adults, juveniles, neonates, 

group composition, etc.); 

• Description of any marine mammal 

behavioral observations (e.g., observed 

behaviors such as feeding or traveling), 

including an assessment of behavioral 

responses thought to have resulted from 

the activity (e.g., no response or changes 

in behavioral state such as ceasing 

feeding, changing direction, flushing, or 

breaching); 

• Number of marine mammals 

detected within the harassment zones, 

by species; and 

• Detailed information about 

implementation of any mitigation (e.g., 

shutdowns and delays), a description of 

specified actions that ensued, and 


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resulting changes in behavior of the 

animal(s), if any. 

If no comments are received from 

NMFS within 30 days, the draft reports 

will constitute the final reports. If 

comments are received, a final report 

addressing NMFS’ comments will be 

required to be submitted within 30 days 

after receipt of comments. All PSO 

datasheets and/or raw sighting data will 

be submitted with the draft marine 

mammal report. 

Reporting of Injured or Dead Marine 

Mammals 

In the event that personnel involved 

in the construction activities discover 

an injured or dead marine mammal, the 

Navy must report the incident to NMFS 

Office of Protected Resources (OPR) 

(PR.ITP.MonitoringReports@noaa.gov), 

NMFS (301–427–8401) and to the NMFS 

Northwest Regional Stranding 

Coordinator as soon as feasible. If the 

death or injury was clearly caused by 

the specified activity, the Navy must 

immediately cease the specified 

activities until NMFS OPR is able to 

review the circumstances of the incident 

and determine what, if any, additional 

measures are appropriate to ensure 

compliance with the terms of this rule. 

The Navy will not resume their 

activities until notified by NMFS. The 

report must include the following 

information: 

1. Time, date, and location (latitude/ 

longitude) of the first discovery (and 

updated location information if known 

and applicable); 

2. Species identification (if known) or 

description of the animal(s) involved; 

3. Condition of the animal(s) 

(including carcass condition if the 

animal is dead); 

4. Observed behaviors of the 

animal(s), if alive; 

5. If available, photographs or video 

footage of the animal(s); and General 

circumstances under which the animal 

was discovered. 

Negligible Impact Analysis and 

Determination 

NMFS has defined negligible impact 

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 

(50 CFR 216.103). A negligible impact 

finding is based on the lack of likely 

adverse effects on annual rates of 

recruitment or survival (i.e., populationlevel effects). An estimate of the number 

of takes alone is not enough information 

on which to base an impact 

determination. In addition to 

considering estimates of the number of 

marine mammals that might be taken 

through harassment, NMFS considers 

other factors, such as the likely nature 

of any impacts or responses (e.g., 

intensity, duration), the context of any 

impacts or responses (e.g., critical 

reproductive time or location, foraging 

impacts affecting energetics), as well as 

effects on habitat, and the likely 

effectiveness of the mitigation. We also 

assess the number, intensity, and 

context of estimated takes by evaluating 

this information relative to population 

status. Consistent with the 1989 

preamble for NMFS’ implementing 

regulations (54 FR 40338, September 29, 

1989), the impacts from other past and 

ongoing anthropogenic activities are 

incorporated into this analysis via their 

impacts on the baseline (e.g., as 

reflected in the regulatory status of the 

species, population size and growth rate 

where known, ongoing sources of 

human-caused mortality, or ambient 

noise levels). 

To avoid repetition, the discussion of 

our analysis applies to the species listed 

in table 12, given that many of the 

anticipated effects of this project on 

different marine mammal stocks are 

expected to be relatively similar in 

nature. Where there are meaningful 

differences among species, stocks, or 

groups of species, anticipated responses 

of individual animals to activities, and/ 

or impacts of expected take on the 

population (due to differences in 

population status, or impacts on 

habitat), the outliers are described 

independently in the analysis below. 

Pile driving activities associated with 

the project, as outlined previously, have 

the potential to disturb or displace 

marine mammals. Specifically, the 

specified activities may result in take, in 

the form of Level A and Level B 

harassment from underwater sounds 

generated by pile driving. Potential 

takes could occur if marine mammals 

are present in zones ensonified above 

the thresholds for Level A and Level B 

harassment, identified above, while 

activities are underway. 

No serious injury or mortality would 

be expected even in the absence of the 

mitigation measures. During all impact 

driving, implementation of soft-start 

procedures and monitoring of 

established shutdown zones will be 

required, significantly reducing the 

possibility of injury. Given sufficient 

notice through use of soft-start (for 

impact driving), marine mammals are 

expected to move away from an 

irritating sound source before it 

becomes potentially injurious. In 

addition, PSOs will be stationed within 

the project area whenever pile driving 

activities are underway. Depending on 

the activity, the Navy will employ landbased PSOs to ensure all monitoring and 

shutdown zones are properly observed. 

For monitoring of larger harassment 

zones, the Navy will employ vesselbased PSOs if practicable. Some harbor 

seals could be exposed to Level A 

harassment levels of noise when they 

swim through the area near the 

Ammunition Wharf during impact pile 

driving. Pile driving will shut down 

whenever a seal is detected by PSOs 

nearing or within the injury zone, but 

harbor seals can dive for up to 15 

minutes and may not be detected. Any 

animals that experience PTS would 

likely only receive slight PTS, i.e., 

minor degradation of hearing 

capabilities within regions of hearing 

that align most completely with the 

frequency range of the energy produced 

by pile driving (i.e., the low-frequency 

region below 2 kHz), not severe hearing 

impairment or impairment in the range 

of greatest hearing sensitivity. If hearing 

impairment does occur, it is most likely 

that the affected animal would lose a 

few dBs in its hearing sensitivity, 

which, in most cases, is not likely to 

meaningfully affect its ability to forage 

and communicate with conspecifics. As 

described above, we expect that, given 

sufficient notice through use of softstart, marine mammals would be likely 

to move away from a sound source that 

represents an aversive stimulus, 

especially when the sound source is at 

levels that would be expected to result 

in PTS. For most pile driving activities, 

exposure of harbor seals to pile driving 

noise will be minimized to short-term 

behavioral harassment (Level B 

harassment). 

Exposures to elevated sound levels 

produced during pile driving activities 

may cause behavioral disturbance of 

some individuals, but the behavioral 

disturbances are expected to be mild 

and temporary. However, as described 

previously, the mitigation and 

monitoring measures are expected to 

further reduce the likelihood of injury 

as well as reduce behavioral 

disturbances. 

Effects on individuals that are taken 

by Level B harassment, as enumerated 

in the Estimated Take section, on the 

basis of reports in the literature as well 

as monitoring from other similar 

activities, will likely be limited to 

reactions such as increased swimming 

speeds, increased surfacing time, or 

decreased foraging (if such activity were 

occurring) (e.g., Thorson and Reyff, 

2006). Most likely, individual animals 

will simply move away from the sound 

source and be temporarily displaced 

from the areas of pile driving, although 


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even this reaction has been observed 

primarily only in association with 

impact pile driving. The pile driving 

activities analyzed here are similar to, or 

less impactful than, numerous other 

construction activities conducted along 

both Atlantic and Pacific coasts, which 

have taken place with no known longterm adverse consequences from 

behavioral harassment. These reactions 

and behavioral changes are expected to 

subside quickly when the exposures 

cease. Level B harassment will be 

minimized through use of mitigation 

measures described herein, and, if 

sound produced by project activities is 

sufficiently disturbing, animals are 

likely to simply avoid the area while the 

activity is occurring, particularly as the 

project is located on a waterfront with 

vessel traffic from both Navy and nonNavy activities. 

The project is also not expected to 

have significant adverse effects on any 

marine mammal habitat. The Navy’s 

planned pile driving activities and 

associated impacts will occur within a 

limited portion of the confluence of the 

Puget Sound-Port Townsend Bay area. 

The project activities will not modify 

existing marine mammal habitat since 

the project will occur within the same 

footprint as existing marine 

infrastructure. Impacts to the immediate 

substrate during installation and 

removal of piles are anticipated, but 

these would be limited to minor, 

temporary suspension of sediments, 

which could impact water quality and 

visibility for a short amount of time, but 

which would not be expected to have 

any effects on individual marine 

mammals. The nearshore and intertidal 

habitat where the project will occur is 

an area of consistent vessel traffic from 

Navy and non-Navy vessels, and some 

local individuals would likely be 

somewhat habituated to the level of 

activity in the area, further reducing the 

likelihood of more severe impacts. The 

closest pinniped haulout, Rat Island, is 

used by harbor seals and is 2.4 km from 

the Ammunition Wharf. However, for 

the reasons described immediately 

above (including the nature of expected 

responses and the duration of the 

project), impacts to reproduction or 

survival of individuals are not 

anticipated, and are not expected to 

have effects on the species or stock. 

There are no other biologically 

important areas for marine mammals 

near the project area. 

Impacts to marine mammal prey 

species are expected to be minor and 

temporary. Overall, the area impacted 

by the project is very small compared to 

the available habitat in Port Townsend 

Bay and larger Puget Sound. The most 

likely impact to prey will be temporary 

behavioral avoidance of the immediate 

area. During pile driving activities, it is 

expected that some fish and marine 

mammals would temporarily leave the 

area of disturbance, thus impacting 

marine mammals’ foraging 

opportunities in a limited portion of the 

foraging range; but, because of the short 

duration of the activities and the 

relatively small area of the habitat that 

may be affected, the impacts to marine 

mammal habitat are not expected to 

cause significant or long-term negative 

consequences. 

In summary and as described above, 

the following factors primarily support 

our determination that the impacts 

resulting from this activity are not 

expected to adversely affect the species 

or stock through effects on annual rates 

of recruitment or survival: 

• No mortality is anticipated or 

authorized; 

• No Level A harassment is 

anticipated or authorized with the 

exception of limited take of harbor seals; 

• Anticipated incidents of Level B 

harassment consist of, at worst, 

temporary modifications in behavior; 

• The required mitigation measures 

(i.e., shutdown zones) are expected to be 

effective in reducing the effects of the 

specified activity; 

• Minimal impacts to marine 

mammal habitat/prey are expected; and 

• There are no known biologically 

important areas in the vicinity of the 

project, with the exception of one 

harbor seal haulout (Rat Island). 

However, as described above, exposure 

to the work conducted in the vicinity of 

the haulout is not expected to impact 

the reproduction or survival of any 

individual seals. 

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 

monitoring and mitigation measures, 

NMFS finds that the total marine 

mammal take from the planned activity 

will have a negligible impact on all 

affected marine mammal species or 

stocks. 

Small Numbers 

As noted previously, only small 

numbers of incidental take may be 

authorized under sections 101(a)(5)(A) 

and (D) of the MMPA for specified 

activities other than military readiness 

activities. The MMPA does not define 

small numbers and so, in practice, 

where estimated numbers are available, 

NMFS compares the number of 

individuals taken to the most 

appropriate estimation of abundance of 

the relevant species or stock in our 

determination of whether an 

authorization is limited to small 

numbers of marine mammals. When the 

predicted number of individuals to be 

taken is fewer than one-third of the 

species or stock abundance, the take is 

considered to be of small numbers. 

Additionally, other qualitative factors 

may be considered in the analysis, such 

as the temporal or spatial scale of the 

activities. 

Take of eight marine mammal stocks 

authorized for take will comprise no 

more than 6.11 percent of a single stock 

abundance (Pacific harbor seal) as 

shown in table 11. The number of 

animals authorized to be taken from 

these stocks would be considered small 

relative to the relevant stock’s 

abundances even if each estimated take 

occurred to a new individual, which is 

an unlikely scenario. Based on the 

analysis contained herein of the 

planned activity (including the 

mitigation and monitoring measures) 

and the anticipated take of marine 

mammals, NMFS finds that small 

numbers of marine mammals will be 

taken relative to the population size of 

the affected species or stocks. 

Unmitigable Adverse Impact Analysis 

and Determination 

There are no relevant subsistence uses 

of the affected marine mammal stocks or 

species implicated by this action. 

Therefore, NMFS has determined that 

the total taking of affected species or 

stocks will not have an unmitigable 

adverse impact on the availability of 

such species or stocks for taking for 

subsistence purposes. 

Adaptive Management 

The regulations governing the take of 

marine mammals incidental to Navy 

construction activities will contain an 

adaptive management component. The 

reporting requirements associated with 

this rule are designed to provide NMFS 

with monitoring data from completed 

projects to allow consideration of 

whether any changes are appropriate. 

The use of adaptive management allows 

NMFS to consider new information 

from different sources to determine 

(with input from the Navy regarding 

practicability) on an annual or biennial 

basis if mitigation or monitoring 

measures should be modified (including 

additions or deletions). Mitigation 

measures could be modified if new data 

suggests that such modifications would 

have a reasonable likelihood of reducing 

adverse effects to marine mammals and 

if the measures are practicable. 

The following are some of the 

possible sources of applicable data to be 


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considered through the adaptive 

management process: (1) Results from 

monitoring reports, as required by 

MMPA authorizations; (2) results from 

general marine mammal and sound 

research; and (3) any information which 

reveals that marine mammals may have 

been taken in a manner, extent, or 

number not authorized by these 

regulations or LOAs issues pursuant to 

these regulations. 

Endangered Species Act 

Section 7(a)(2) of the ESA of 1973 (16 

U.S.C. 1531 et seq.) requires that each 

Federal agency insure that any action it 

authorizes, funds, or carries out is not 

likely to jeopardize the continued 

existence of any endangered or 

threatened species or result in the 

destruction or adverse modification of 

designated critical habitat. To ensure 

ESA compliance for the issuance of 

rules, NMFS consults internally 

whenever we propose to authorize take 

for endangered or threatened species, in 

this case with the NMFS West Coast 

Regional Office. 

No incidental take of ESA-listed 

species is authorized or expected to 

result from this activity. Therefore, 

NMFS has determined that consultation 

under section 7 of the ESA is not 

required for this action. 

Classification 

Pursuant to the procedures 

established to implement Executive 

Order 12866, the Office of Management 

and Budget has determined that this 

rule is not significant. 

Pursuant to section 605(b) of the 

Regulatory Flexibility Act (RFA), the 

Chief Counsel for Regulation of the 

Department of Commerce certified to 

the Chief Counsel for Advocacy of the 

Small Business Administration at the 

proposed rule stage that this action will 

not have a significant economic impact 

on a substantial number of small 

entities. The Navy is the sole entity that 

will be subject to the requirements in 

these regulations, and the Navy is not a 

small governmental jurisdiction, small 

organization, or small business, as 

defined by the RFA. No comments were 

received regarding this certification or 

on the economic impacts of the rule 

more generally. As a result, a regulatory 

flexibility analysis is not required and 

none has been prepared. 

This rule does not contain a 

collection-of-information requirement 

subject to the provisions of the 

Paperwork Reduction Act (PRA) 

because the applicant is a Federal 

agency. 

List of Subjects in 50 CFR Part 217 

Administrative practice and 

procedure, Exports, Fish, Imports, 

Marine mammals, Penalties, Reporting 

and recordkeeping requirements, 

Transportation, Wildlife. 

Dated: January 23, 2024. 

Samuel D. Rauch, III, 

Deputy Assistant Administrator for 

Regulatory Programs, National Marine 

Fisheries Service. 

For reasons set forth in the preamble, 

NMFS revises subpart I of 50 CFR part 

217 as follows: 

PART 217—REGULATIONS 

GOVERNING THE TAKE OF MARINE 

MAMMALS INCIDENTAL TO 

SPECIFIED ACTIVITIES 

■ 1. The authority citation for part 217 

continues to read as follows: 

Authority: 16 U.S.C. 1361 et seq., unless 

otherwise noted. 

■ 2. Revise subpart I, consisting of 

§§ 217.80 through 217.89, to read as 

follows: 

Subpart I—Taking Marine Mammals 

Incidental to U.S. Navy Construction at the 

Naval Magazine Indian Island Ammunition 

Wharf, Puget Sound, Washington 

Sec. 

217.80 Specified activity and geographical 

region. 

217.81 Effective dates. 

217.82 Permissible methods of taking. 

217.83 Prohibitions. 

217.84 Mitigation requirements. 

217.85 Requirements for monitoring and 

reporting. 

217.86 Letters of Authorization. 

217.87 Renewals and modifications of 

Letters of Authorization. 

217.88–217.89 [Reserved] 

Subpart I—Taking Marine Mammals 

Incidental to U.S. Navy Construction at 

the Naval Magazine Indian Island 

Ammunition Wharf, Puget Sound, 

Washington 

§ 217.80 Specified activity and 

geographical region. 

(a) Regulations in this subpart apply 

only to the U.S. Navy (Navy) and those 

persons it authorizes or funds to 

conduct activities on its behalf for the 

taking of marine mammals that occur in 

the areas outlined in paragraph (b) of 

this section and that occur incidental to 

construction activities, including 

maintenance and replacement of piles, 

at the Naval Magazine Indian Island 

Ammunition Wharf, Puget Sound, 

Washington. 

(b) The taking of marine mammals by 

the Navy may be authorized in a Letter 

of Authorization (LOA) only if it occurs 

at the Naval Magazine Indian Island 

Ammunition Wharf, Puget Sound, 

Washington. 

§ 217.81 Effective dates. 

Regulations in this subpart are 

effective from October 1, 2024, until 

September 30, 2029. 

§ 217.82 Permissible methods of taking. 

Under an LOA issued pursuant to 

§ 216.106 of this chapter and § 217.86, 

the Holder of the LOA (hereinafter 

‘‘Navy’’) may incidentally, but not 

intentionally, take marine mammals 

within the area described in § 217.80 (b) 

by harassment associated with 

construction activities, provided the 

activity is in compliance with all terms, 

conditions, and requirements of the 

regulations in this subpart and the 

applicable LOA. 

§ 217.83 Prohibitions. 

(a) Except for the takings 

contemplated in § 217.82 and 

authorized by a LOA issued under 

§§ 216.106 of this chapter and 217.86, it 

is unlawful for any person to do any of 

the following in connection with the 

activities described in § 217.80: 

(1) Violate, or fail to comply with, the 

terms, conditions, and requirements of 

this subpart or a LOA issued under 

§ 216.106 of this chapter and § 217.86; 

(2) Take any marine mammal not 

specified in such LOA; 

(3) Take any marine mammal 

specified in such LOA in any manner 

other than as specified; 

(4) Take a marine mammal specified 

in such LOA if NMFS determines such 

taking results in more than a negligible 

impact on the species or stocks of such 

marine mammal; or 

(5) Take a marine mammal specified 

in such LOA after NMFS determines 

such taking results in an unmitigable 

adverse impact on the species or stock 

of such marine mammal for taking for 

subsistence uses. 

(b) [Reserved] 

§ 217.84 Mitigation requirements. 

(a) When conducting the activities 

identified in § 217.80(a), the mitigation 

measures contained in any LOA issued 

under §§ 216.106 of this chapter and 

§§ 217.86 or 217.87 must be 

implemented. These mitigation 

measures include but are not limited to: 

(1) A copy of any issued LOA must be 

in the possession of the Navy, its 

designees, and work crew personnel 

operating under the authority of the 

issued LOA; 

(2) The Navy must follow mitigation 

procedures as described in § 217.84. 

Protected Species Observers (PSO) must 

monitor designated harassment zones 


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described in the LOA to the maximum 

extent practicable based on daily 

visibility conditions. 

(3) The Navy must ensure that 

construction supervisors and crews, the 

PSO team, and relevant Navy staff are 

trained prior to the start of construction 

activity subject to this rule, so that 

responsibilities, communication 

procedures, monitoring protocols, and 

operational procedures are clearly 

understood. New personnel joining 

during the project must be trained prior 

to commencing work; 

(4) The Navy must avoid direct 

physical interaction with marine 

mammals during construction activity. 

If a marine mammal comes within 10 m 

of such activity, operations must cease 

and vessels must reduce speed to the 

minimum level required to maintain 

steerage and safe working conditions, as 

necessary, to avoid direct physical 

interaction; 

(5) For all pile driving activity, the 

Navy must implement shutdown zones 

with radial distances as identified in a 

LOA issued under § 216.106 of this 

chapter and §§ 217.86 or 217.87. If a 

marine mammal comes within or 

approaches the shutdown zone, pile 

driving activity must cease; 

(6) The Navy must shut down inwater activities when cetaceans are 

observed approaching or within any 

harassment zone; 

(7) The Navy must use soft start 

techniques when impact pile driving. 

Soft start requires an initial set of three 

strikes from the hammer at reduced 

energy, followed by a 30-second waiting 

period. Then two subsequent reducedenergy strike sets would occur. A soft 

start must be implemented at the start 

of each day’s impact pile driving and at 

any time following cessation of impact 

pile driving for a period of 30 minutes 

or longer; 

(8) The Navy must employ bubble 

curtain systems during impact driving 

of 36-in steel piles except under 

conditions where the water depth is less 

than 0.67 meters (2 feet) in depth. 

Bubble curtains must meet the following 

requirements; 

(i) The bubble curtain must distribute 

air bubbles around 100 percent of the 

piling perimeter for the full depth of the 

water column; 

(ii) The lowest bubble ring must be in 

contact with the mudline and/or rock 

bottom for the full circumference of the 

ring, and the weights attached to the 

bottom ring shall ensure 100 percent 

mudline and/or rock bottom contact. No 

parts of the ring or other objects shall 

prevent full mudline and/or rock bottom 

contact; and 

(iii) The bubble curtain must be 

operated such that there is equal 

balancing of air flow to all bubblers; 

(9) The Navy must deploy PSOs as 

indicated in its Marine Mammal 

Monitoring Plan that has been approved 

by NMFS; 

(10) For all pile driving activities, 

land-based PSOs must be stationed at 

the best vantage points practicable to 

monitor for marine mammals and 

implement shutdown/delay procedures. 

At least one vessel-based PSO must be 

employed when practicable. Additional 

PSOs must be added if warranted by site 

conditions and/or the level of marine 

mammal activity in the area; 

(11) Monitoring must take place from 

30 minutes prior to initiation of pile 

driving activity (i.e., pre-start clearance 

monitoring) through 30 minutes postcompletion of pile driving activity. Preactivity monitoring must be conducted 

for 30 minutes to ensure that the 

shutdown zone is clear of marine 

mammals, and pile driving may only 

commence when PSOs have declared 

the shutdown zone clear of marine 

mammals; 

(12) In the event of a delay or 

shutdown of activity resulting from 

marine mammals in the shutdown zone, 

animals must be allowed to remain in 

the shutdown zone (i.e., must leave of 

their own volition) and their behavior 

must be monitored and documented. If 

a marine mammal is observed within 

the shutdown zone, a soft start cannot 

proceed until the animal has left the 

zone or has not been observed for 15 

minutes. Monitoring must occur 

throughout the time required to drive a 

pile; 

(13) If work ceases for more than 30 

minutes, the pre-activity monitoring of 

the shutdown zones must commence. A 

determination that the shutdown zone is 

clear must be made during a period of 

good visibility; 

(14) If a marine mammal approaches 

or enters the shutdown zone, all pile 

driving activities at that location must 

be halted. If pile driving is halted or 

delayed due to the presence of a marine 

mammal, the activity may not 

commence or resume until either the 

animal has voluntarily left and been 

visually confirmed beyond the 

shutdown zone or 15 minutes have 

passed without re-detection of the 

animal; 

(15) Pile driving activity must be 

halted upon observation of a species 

entering or within the harassment zone 

for either a species for which incidental 

take is not authorized or a species for 

which incidental take has been 

authorized but the authorized number of 

takes has been met; and 

(16) Trained PSOs must be placed at 

the best vantage point(s) practicable to 

monitor for marine mammals and 

implement shutdown or delay 

procedures when applicable through 

communication with the equipment 

operator. 

(b) [Reserved] 

§ 217.85 Requirements for monitoring and 

reporting. 

(a) The Navy must submit a Marine 

Mammal Monitoring Plan to NMFS for 

approval at least 90 days before the start 

of construction and abide by the Plan if 

approved. 

(b) The Navy must deploy PSOs as 

indicated in its approved Marine 

Mammal Monitoring Plan. 

(c) Monitoring must be conducted by 

qualified, NMFS-approved PSOs, in 

accordance with the following 

conditions: 

(1) PSOs must be independent of the 

activity contractor (for example, 

employed by a subcontractor) and have 

no other assigned tasks during 

monitoring periods; 

(2) At least one PSO must have prior 

experience performing the duties of a 

PSO during construction activity 

pursuant to a NMFS-issued incidental 

take authorization; 

(3) Other PSOs may substitute other 

relevant experience, education (degree 

in biological science or related field), or 

training for prior experience performing 

the duties of a PSO during construction 

activity pursuant to a NMFS-issued 

incidental take authorization; 

(4) Where a team of three or more 

PSOs are required, a lead PSO or 

monitoring coordinator must be 

designated. The lead PSO must have 

prior experience performing the duties 

of a PSO during construction activity 

pursuant to a NMFS-issued incidental 

take authorization; and 

(5) PSOs must be approved by NMFS 

prior to beginning any activity subject to 

these regulations. 

(d) PSOs must be trained in marine 

mammal identification and behaviors. 

(e) The Navy must monitor the Level 

B harassment zones (areas where SPLs 

are equal to or exceed the 160 dB rootmean-squared (rms) threshold for 

impact driving and the 120 dB rms 

threshold during vibratory pile driving) 

to the maximum extent practicable and 

the shutdown zones. 

(f) The Navy must coordinate with the 

Center for Whale Research, Orca 

network, and NMFS to avoid noise 

exposure of southern resident killer 

whales. The Navy must shut down inwater activities when southern resident 

killer whales are observed or reported 

within or approaching any harassment 

zone. 


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(g) The Navy must submit a draft 

monitoring report to NMFS within 90 

calendar days of the completion of each 

construction year. A draft 

comprehensive 5-year summary report 

must also be submitted to NMFS within 

90 days of the end of the project. The 

reports must detail the monitoring 

protocol and summarize the data 

recorded during monitoring. Final 

annual reports and the final 

comprehensive report must be prepared 

and submitted within 30 days following 

resolution of any NMFS comments on 

the draft report. If no comments are 

received from NMFS within 30 days of 

receipt of the draft report, the report 

must be considered final. If comments 

are received, a final report addressing 

NMFS comments must be submitted 

within 30 days after receipt of 

comments. The reports must contain the 

informational elements described at 

minimum below including: 

(1) Dates and times (begin and end) of 

all marine mammal monitoring; 

(2) Construction activities occurring 

during each daily observation period, 

including how many and what type of 

piles were driven or removed, by what 

method (i.e., impact or vibratory), the 

total duration of driving time for each 

pile (vibratory driving), and number of 

strikes for each pile (impact driving); 

(3) Environmental conditions during 

monitoring periods (at beginning and 

end of PSO shift and whenever 

conditions change significantly), 

Beaufort sea state, and any other 

relevant weather conditions including 

cloud cover, fog, sun glare, and overall 

visibility to the horizon, and estimated 

observable distance (if less than the 

harassment zone distance); 

(4) Upon observation of a marine 

mammal, the following information 

should be collected: 

(i) PSO who sighted the animal, 

observer location, and activity at time of 

sighting: 

(ii) Time of sighting; 

(iii) Identification of the animal (e.g., 

genus/species, lowest possible 

taxonomic level, or unidentified), PSO 

confidence in identification, and the 

composition of the group if there is a 

mix of species; 

(iv) Distances and bearings of each 

marine mammal observed in relation to 

the pile being driven for each sighting 

(if pile driving was occurring at time of 

sighting); 

(v) Estimated number of animals 

(min/max/best); 

(vi) Estimated number of animals by 

cohort (adults, juveniles, neonates, 

group composition, etc.); 

(vii) Animal’s closest point of 

approach and estimated time spent 

within the harassment zone; 

(viii) Description of any marine 

mammal behavioral observations (e.g., 

observed behaviors such as feeding or 

traveling), including an assessment of 

behavioral responses to the activity (e.g., 

no response or changes in behavioral 

state such as ceasing feeding, changing 

direction, flushing, or breaching); 

(ix) Detailed information about any 

implementation of any mitigation (e.g., 

shutdowns and delays), a description of 

specific actions that ensued, and 

resulting changes in the behavior of the 

animal, if any; and 

(x) All PSO datasheets and/or raw 

sightings data. 

(h) In the event that personnel 

involved in the construction activities 

discover an injured or dead marine 

mammal, the Navy must report the 

incident to NMFS Office of Protected 

Resources (OPR), and to the West Coast 

Regional Stranding Coordinator, as soon 

as feasible. If the death or injury was 

caused by the specified activity, the 

Navy must immediately cease the 

specified activities until NMFS OPR is 

able to review the circumstances of the 

incident and determine what, if any, 

additional measures are appropriate to 

ensure compliance with the terms of 

this rule and the LOA issued under 

§ 216.106 of this chapter and § 217.86. 

The Navy must not resume their 

activities until notified by NMFS. The 

report must include the following 

information: 

(1) Time, date, and location (latitude/ 

longitude) of the first discovery (and 

updated location information if known 

and applicable); 

(2) Species identification (if known) 

or description of the animal(s) involved; 

(3) Condition of the animal(s) 

(including carcass condition if the 

animal is dead); 

(4) Observed behaviors of the 

animal(s), if alive; 

(5) If available, photographs or video 

footage of the animal(s); and 

(6) General circumstances under 

which the animal was discovered. 

§ 217.86 Letters of Authorization. 

(a) To incidentally take marine 

mammals pursuant to these regulations, 

the Navy must apply for and obtain an 

LOA. 

(b) An LOA, unless suspended or 

revoked, may be effective for a period of 

time not to exceed the expiration date 

of these regulations. 

(c) If an LOA expires prior to the 

expiration date of these regulations, the 

Navy may apply for and obtain a 

renewal of the LOA. 

(d) In the event of projected changes 

to the activity or to mitigation and 

monitoring measures required by an 

LOA, the Navy must apply for and 

obtain a modification of the LOA as 

described in § 217.87. 

(e) The LOA must set forth the 

following information: 

(1) Permissible methods of incidental 

taking; 

(2) Means of effecting the least 

practicable adverse impact (i.e., 

mitigation) on the species, its habitat, 

and on the availability of the species for 

subsistence uses; and 

(3) Requirements for monitoring and 

reporting. 

(f) Issuance of the LOA must be based 

on a determination that the level of 

taking will be consistent with the 

findings made for the total taking 

allowable under these regulations. 

(g) Notice of issuance or denial of an 

LOA must be published in the Federal 

Register within 30 days of a 

determination. 

§ 217.87 Renewals and modifications of 

Letters of Authorization. 

(a) An LOA issued under §§ 216.106 

of this chapter and 217.86 for the 

activity identified in § 217.80(a) may be 

renewed or modified upon request by 

the applicant, provided that: 

(1) The specified activity and 

mitigation, monitoring, and reporting 

measures, as well as the anticipated 

impacts, are the same as those described 

and analyzed for these regulations; and 

(2) NMFS determines that the 

mitigation, monitoring, and reporting 

measures required by the previous LOA 

under these regulations were 

implemented. 

(b) For LOA modification or renewal 

requests by the applicant that include 

changes to the activity or the mitigation, 

monitoring, or reporting that do not 

change the findings made for the 

regulations or result in no more than a 

minor change in the total estimated 

number of takes (or distribution by 

species or years), NMFS may publish a 

notice of proposed LOA in the Federal 

Register, including the associated 

analysis of the change, and solicit 

public comment before issuing the LOA. 

(c) An LOA issued under §§ 216.106 

of this chapter and 217.86 for the 

activity identified in § 217.80 (a) may be 

modified by NMFS under the following 

circumstances: 

(1) NMFS may modify (including 

augment) the existing mitigation, 

monitoring, or reporting measures (after 

consulting with Navy regarding the 

practicability of the modifications) if 

doing so creates a reasonable likelihood 

of more effectively accomplishing the 


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Federal Register / Vol. 89, No. 19 / Monday, January 29, 2024 / Rules and Regulations 5695 

goals of the mitigation and monitoring 

set forth in the preamble for these 

regulations; 

(i) Possible sources of data that could 

contribute to the decision to modify the 

mitigation, monitoring, or reporting 

measures in an LOA: 

(A) Results from Navy’s monitoring 

from previous years; 

(B) Results from other marine 

mammal and/or sound research or 

studies; and 

(C) Any information that reveals 

marine mammals may have been taken 

in a manner, extent or number not 

authorized by these regulations or 

subsequent LOAs; and 

(ii) If, through adaptive management, 

the modifications to the mitigation, 

monitoring, or reporting measures are 

substantial, NMFS must publish a 

notice of proposed LOA in the Federal 

Register and solicit public comment; 

and 

(2) If NMFS determines that an 

emergency exists that poses a significant 

risk to the well-being of the species or 

stocks of marine mammals specified in 

a LOA issued pursuant to §§ 216.106 of 

this chapter and 217.86, a LOA may be 

modified without prior notice or 

opportunity for public comment. 

Notification will be published in the 

Federal Register within 30 days of the 

action. 

§§ 217.88–217.89 [Reserved] 

[FR Doc. 2024–01558 Filed 1–26–24; 8:45 am] 

BILLING CODE 3510–22–P 


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