Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 46199 

2021, provided the previously 

mentioned mitigation, monitoring, and 

reporting requirements are incorporated. 

Dated: August 11, 2021. 

Catherine Marzin, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2021–17683 Filed 8–17–21; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

Reopening of Solicitation of 

Nominations for the Marine Debris 

Foundation Board of Directors 

AGENCY: National Ocean Service (NOS), 

National Oceanic and Atmospheric 

Administration (NOAA), Department of 

Commerce (DOC). 

ACTION: Reopening of solicitation of 

nominations. 

SUMMARY: The National Oceanic and 

Atmospheric Administration published 

a notice in the Federal Register on May 

19, 2021 seeking nominations of 

qualified candidates to be considered 

for appointment as a member of the 

Marine Debris Foundation Board of 

Directors (Board). This solicitation of 

nominations of qualified persons to the 

Board is hereby reopened. 

DATES: Nominations to the Board of 

Directors for the Marine Debris 

Foundation must be received in entirety 

no later than 11:59 p.m. EDT on August 

27, 2021. Nomination packages received 

after this time will not be considered. 

ADDRESSES: All nominations should be 

emailed (recommended) to 

marinedebris.foundation@noaa.gov 

with the subject line ‘‘Marine Debris 

Foundation Nomination,’’ or mailed to 

Caitlin Wessel, Marine Debris 

Foundation Nomination, c/o NOAA 

Disaster Response Center, 7344 Ziegler 

Blvd., Mobile, AL 36608. 

FOR FURTHER INFORMATION CONTACT: 

Caitlin Wessel, Ph.D., Phone 251–222– 

0276; Email caitlin.wessel@noaa.gov or 

visit the NOAA Marine Debris Program 

website at https://

marinedebris.noaa.gov/who-we-are/ 

marine-debris-foundation. 

SUPPLEMENTARY INFORMATION: Refer to 

the Federal Register Notice of May 19, 

2021 (86 FR 27070) and the NOAA 

Marine Debris Program website at 

https://marinedebris.noaa.gov/who-weare/marine-debris-foundation for the 

items that are required parts of the 

nomination package and additional 

information. 

(Authority: Pub. L. 116–224, 112, Dec. 18, 

2020, 134 Stat. 1072) 

Scott Lundgren, 

Director, Office of Response and Restoration, 

National Ocean Service. 

[FR Doc. 2021–17738 Filed 8–17–21; 8:45 am] 

BILLING CODE 3510–NK–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XB163] 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to the Palmer 

Station Pier Replacement Project, 

Antarctica 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; proposed incidental 

harassment authorization; request for 

comments on proposed authorization 

and possible renewal. 

SUMMARY: NMFS has received a request 

from the National Science Foundation 

(NSF) for authorization to take marine 

mammals incidental to the Palmer 

Station Pier Replacement Project in 

Anvers Island, Antarctica. Pursuant to 

the Marine Mammal Protection Act 

(MMPA), NMFS is requesting comments 

on its proposal to issue an incidental 

harassment authorization (IHA) to 

incidentally take marine mammals 

during the specified activities. NMFS is 

also requesting comments on a possible 

one-time, one-year renewal that could 

be issued under certain circumstances 

and if all requirements are met, as 

described in Request for Public 

Comments at the end of this notice. 

NMFS will consider public comments 

prior to making any final decision on 

the issuance of the requested MMPA 

authorizations and agency responses 

will be summarized in the final notice 

of our decision. 

DATES: Comments and information must 

be received no later than September 17, 

2021. 

ADDRESSES: Comments should be 

addressed to Jolie Harrison, Chief, 

Permits and Conservation Division, 

Office of Protected Resources, National 

Marine Fisheries Service. Written 

comments should be submitted via 

email to ITP.Pauline@noaa.gov. 

Instructions: NMFS is not responsible 

for comments sent by any other method, 

to any other address or individual, or 

received after the end of the comment 

period. Comments, including all 

attachments, must not exceed a 25- 

megabyte file size. All comments 

received are a part of the public record 

and will generally be posted online at 

www.fisheries.noaa.gov/permit/ 

incidental-take-authorizations-undermarine-mammal-protection-act without 

change. All personal identifying 

information (e.g., name, address) 

voluntarily submitted by the commenter 

may be publicly accessible. Do not 

submit confidential business 

information or otherwise sensitive or 

protected information. 

FOR FURTHER INFORMATION CONTACT: 

Robert Pauline, Office of Protected 

Resources, NMFS, (301) 427–8401. 

Electronic copies of the application and 

supporting documents, as well as a list 

of the references cited in this document, 

may be obtained online at: https://

www.fisheries.noaa.gov/permit/ 

incidental-take-authorizations-undermarine-mammal-protection-act. In case 

of problems accessing these documents, 

please call the contact listed above. 

SUPPLEMENTARY INFORMATION: 

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 

issued or, if the taking is limited to 

harassment, a notice of a proposed 

incidental take authorization may be 

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. 


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46200 Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 

The definitions of all applicable 

MMPA statutory terms cited above are 

included in the relevant sections below. 

National Environmental Policy Act 

To comply with the National 

Environmental Policy Act of 1969 

(NEPA; 42 U.S.C. 4321 et seq.) and 

NOAA Administrative Order (NAO) 

216–6A, NMFS must review our 

proposed action (i.e., the issuance of an 

IHA) with respect to potential impacts 

on the human environment. 

Accordingly, NMFS plans to adopt 

NSF’s Initial Environmental Evaluation 

(IEE), which is generally the equivalent 

of an environmental assessment (EA) 

under the Antarctic Conservation Act 

(16 U.S.C. 2401 et seq.), provided our 

independent evaluation of the 

document finds that it includes 

adequate information analyzing the 

effects on the human environment of 

issuing the IHA. 

We will review all comments 

submitted in response to this notice and 

the draft IEE prior to concluding our 

NEPA process or making a final 

decision on the IHA request. 

Summary of Request 

On December 29, 2020, NMFS 

received a request from the National 

Science Foundation (NSF) for an IHA to 

take marine mammals incidental to 

construction activities associated with 

the Palmer Station Pier Replacement 

Project on Anvers Island, Antarctica. 

NSF submitted several revisions of the 

application until it was deemed 

adequate and complete on July 15, 2021. 

NSF’s request is for take of a small 

number of 17 species of marine 

mammals by Level B harassment and/or 

Level A harassment. Neither NSF nor 

NMFS expects serious injury or 

mortality to result from this activity 

and, therefore, an IHA is appropriate. 

Description of Proposed Activity 

Overview 

The purpose of the project is to 

construct a replacement pier at Palmer 

Station on Anvers Island, Antarctica for 

the United States Antarctic Program. It 

is severely deteriorated, and needs to be 

replaced as soon as possible. 

Construction of the replacement pier 

and removal of the existing pier will 

require down-the-hole (DTH) pile 

installation, and vibratory pile removal. 

Limited impact driving will occur only 

to proof piles after they have been 

installed. The proposed project is 

expected to take up to 89 days of inwater work and will include the 

installation of 52 piles and removal of 

36 piles. Construction is expected to 

begin no later than November 2021, 

depending on local sea ice conditions, 

and would be completed by mid-April 

2022. The pile driving and removal 

activities can result in take of marine 

mammals from sound in the water 

which results in behavioral harassment 

or auditory injury. Note that hereafter 

(unless otherwise specified) the term 

‘‘pile driving’’ is used to refer to both 

pile installation (including DTH pile 

installation) and pile removal. 

Dates and Duration 

The work described here is likely to 

begin in October or November 2021 and 

would be completed by mid-April 2022 

with demobilization occurring no later 

than June of 2022. The construction 

season is limited due to ice and 

weather. Construction work cannot 

begin until the sea ice has vacated Hero 

Inlet and work must be completed prior 

to the return of sea ice so that personnel 

and equipment can be safely 

demobilized. The proposed IHA would 

be effective for a period of one year from 

October 1, 2021 through September 30, 

2022. In-water activities will occur 

during daylight hours only. Work would 

be conducted 7 days per week for 12 

hours (hr) per day and up to 89 days of 

in-water construction is anticipated. 

Specific Geographic Region 

The activities would occur at Palmer 

Station on Hero Inlet, between Gamage 

Point and Bonaparte Point on the 

southwestern coast of Anvers Island in 

the Antarctica Peninsula (Figure 1). The 

coordinates for the station are: 64°46′ S, 

64°03′ W. Substrate at the project 

location consists of solid rock. In 

addition to the pier, there are several 

buildings, plus two large fuel tanks, and 

a helicopter pad. The area frequently 

experiences high winds, up to 130 

kilometers (km) per hour, or greater. 

Palmer Station lies outside the Antarctic 

Circle, so there are 19 hours of light and 

5 hours of twilight at the height of 

austral summer and only 5 hours of 

daylight each day in the middle of 

austral winter. Hero Inlet is a narrow 

inlet (approximately 135 meters (m) 

wide) along the southwest side of 

Anvers Island. Maximum observed tidal 

range is 2.5 m with mean sea level at 

0.72 m. The shoreline and upland area 

is generally rocky or exposed bedrock. 

Ice cliffs rise above the station. 

BILLING CODE 3510–22–P 


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Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 46201 

BILLING CODE 3510–22–C 

Detailed Description of Specific Activity 

The existing pier at Palmer Station 

consists of a sheetpile bulkhead 

backfilled with gravel and cobble that 

was built in 1967. It is severely 

deteriorated, and needs to be replaced 

as soon as possible. 

This project would replace the 

existing pier with a new steel pipe pile 

supported concrete deck pier, new 

modern energy absorbing fender system 

and on-site power and lighting. Work on 

the fendering system would be above 

water. In-water work with the potential 

to produce underwater noise includes 

demolition of the existing pier, 

construction of the new pier and 

installation of wave attenuator piles. 

While piles for the wave attenuator will 

be installed in this project, the wave 

attenuator itself would be installed later. 

(NMFS does not expect installation of 

the wave attenuator to result in take.) 

The existing bulkhead pier must be 

demolished prior to construction of the 

new pier. The existing sheetpile 

cofferdam bulkhead would be 

demolished and the sheets would be 

removed by a vibratory hammer or cut 

off at the mudline. Sheet pile removed 

from the pier cell would be loaded onto 

the material barge for disposal. A pier 

cell is a structure that has hollow 

sections (i.e., cells). 

New pile installation would include 

steel gravel-filled pipe piles as outlined 

in Table 1. The deck and pile caps for 

the pier are supported by the piles, 

which are installed in holes (sockets) 

created in the shallow bedrock by the 

DTH systems. Support vessels, 

including a tugboat, one stationary 

barge, a temporary floating construction 

platform, a 16-ft. (5-m) skiff and one 200 

horsepower work boat would be used 

for the duration of the project to 

complete in-water work. A separate 

gravel barge would deliver material at 

the beginning of the project, but would 

only be onsite for approximately 3 days. 


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AI.--N!S-'11! _, • » - 1~ 

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e-::...::::,_ I --INFigure 1. Map of Proposed Project Area 
46202 Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 

TABLE 1—PILE SUMMARY

Structure Size and type of pile 

Socket 

depth 

(feet [ft]) 

Number of 

piles 

Pier Abutment ................................... 32 or 36-in. diameter steel pile in approximate 38-in. diameter holes ........ 30 4. 

Pier .................................................... 36-in. steel pile in approximate 38-in. diameter holes ................................ 20 Up to 18.a

Retaining Wall ................................... H pile inserted in 24-in. diameter hole ........................................................ 10 Up to 9.a

Wave Attenuator Piles ...................... 24-in. steel pile ............................................................................................. 20 2. 

Rigid Hull Inflatable Boat Fender ..... 24-in. steel pile ............................................................................................. 20 3. 

Template Piles (temporary) .............. 24-in. steel pile ............................................................................................. 10 32.b

Sheetpile Removal ............................ 3/8-in ............................................................................................................ 0 20. 

a Includes 2 piles as a contingency for design flexibility. 

b 16 of these piles are removed once they are no longer needed as templates. 

The primary source of underwater 

noise that may result in takes during 

construction would be from the 

installation and removal of piles to 

support the pier and fenders. Table 2 

shows project components and activities 

that could result in the take of marine 

mammals. 

TABLE 2—PROJECT COMPONENTS: POTENTIAL FOR MARINE MAMMAL TAKE

Project component Equipment 

Potential for marine 

mammal take 

(yes/no) 

Pile/Sheetpile Removal ........................... Excavator and loader operated above water ........................................................ No. 

Crane operated above water ................................................................................. No. 

Vibratory hammer .................................................................................................. Yes. 

Underwater cutting tool 1 ........................................................................................ Yes. 

Pile Installation ........................................ Crane operated above water ................................................................................. No. 

DTH drill ................................................................................................................. Yes. 

Impact hammer ...................................................................................................... Yes. 

Vibratory hammer .................................................................................................. Yes. 

Anode Protection .................................... Pneumatic hydrogrinder or needle scaler 2 ........................................................... Yes. 

Rock chipping (optional) ......................... Hoe ram ................................................................................................................. Yes.3

1 Underwater cutting tool operation, if necessary, would occur on the same days as vibratory extraction. Estimated take associated with cutting 

tool operation was calculated by utilizing higher underwater source levels associated with vibratory extraction. 2These tools scrape off surfaces for rust, paint, etc. Use of these tools would be limited and would occur once pile installation is complete. Underwater source levels are estimated at 146 dB at 10m and have been accounted for in the take estimate. 3 Rock chipping may not be necessary. However if it does occur it would occur on the same days as DTH pile installation. 

Piles would be socketed in place since 

the substrate comprises rocky or 

exposed bedrock. This involves drilling 

and hammering into the rock to create 

a socket hole deeper and larger than the 

pile diameter. The primary technique 

for creating the socket holes and their 

piles would be by DTH pile installation. 

DTH installation uses both rotary and 

hammering actions on a drill bit (i.e., 

like a hammer drill hand tool) to create 

a hole in the bedrock or sediment. It 

uses the rotation of the drill system and 

a (typically pneumatic) hammering 

mechanism to break up rock to create a 

hole. Since construction techniques 

could vary depending on specific site 

conditions, a small impact hammer may 

also need to be used at the end of the 

process to firmly seat the pile in the 

hole. This may require no more than 10 

strikes. It is unlikely that a vibratory 

hammer would be used to install piles. 

Once the pile is set, the remaining void 

space is filled with a high-performance 

cement-based sealing grout. Temporary 

template piles used during construction 

would be removed with a vibratory 

hammer or cut off at the mudline. 

Approximately one to two piles 

would be installed over a 12-hour work 

day. As a precautionary measure, it is 

assumed that two installation activities 

would be occurring at the same time 

(i.e., simultaneous). The main method of 

pile installation would be by DTH. Two 

DTH systems would be available on site 

and could be used simultaneously. One 

vibratory hammer would possibly be 

used to remove existing piles, and one 

impact hammer could be used to proof 

piles. 

Rock chipping may be required to 

ensure accurate pile location and 

alignment with the sea bottom at pile 

locations. Rock chipping involves the 

use of excavators fitted with hydraulic 

‘‘breakers’’ or powerful percussion 

hammers used to break up large 

concrete structures. If rock chipping is 

necessary, it would likely occur prior to 

but on the same days as DTH pile 

installation. 

The project design includes 

installation of anode corrosion 

protection for the major submerged steel 

components. Divers would install 

aluminum alloy anodes below the 

waterline by welding and using a 

pneumatic hydrogrinder, needle scaler, 

or similar equipment. They would use 

these tools to scrape rust, paint, etc. off 

surfaces. This activity would occur only 

after pile installation is complete. The 

hydrogrinder or needle scaler would 

only be used approximately one hour 

per day over an 18-day period. 

Table 3 provides the number of piles 

and the estimated number of days of 

installation. 


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Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 46203 

TABLE 3—PILE INSTALLATION AND REMOVAL DURATION

Pile type Number of piles Total days of 

installation 1

36-in. piles 2 (pier Bents 2, 3, and 4) ............................................................................................................ Up to 18 ................. 47 

32-in. piles (pier abutment Bent 1) ............................................................................................................... 4.

24-in. RHIB (rigid hull inflatable boat) fender ............................................................................................... 3 ............................. 16 

24-in. template piles ...................................................................................................................................... 16.

24-in. retaining wall ....................................................................................................................................... 2.

24-in. H piles (retaining wall) ........................................................................................................................ Up to 9.

Pile Removal (24-in.) ..................................................................................................................................... 16 ........................... 4 

Sheetpile Removal ........................................................................................................................................ 20 ........................... 4 

Anode Installation .......................................................................................................................................... 0 ............................. 18 

Rock chipping ................................................................................................................................................ 0.

Up to 88 ................. 89 

1This is a conservative estimate. It is possible that 24-in. piles may be driven on the same day as 36-in. piles. If this occurs, overall days may 

be reduced for pile installation. 2For the purposes of calculating take, there is reference to Scenario 1A which involves pile installation of two 36-in piles simultaneously. In this 

table, Scenarios 1 and 1A are synonymous in terms of representing the number of estimated days for installation. 

Description of Marine Mammals in the 

Area of Specified Activities 

Table 4 lists all species or stocks for 

which take is expected and proposed to 

be authorized for this action, and 

summarizes best available information 

on the population or stock, including 

regulatory status under the MMPA and 

Endangered Species Act. For taxonomy, 

we follow Committee on Taxonomy 

(2020). Marine mammals in the Project 

Area do not constitute stocks under U.S. 

jurisdiction; therefore, there are no stock 

assessment reports. Additional 

information on these species may be 

found in Section 3 of NSF’s application. 

For species occurring in United States 

Antarctic Marine Living Resources 

(AMLR) survey area of the Southern 

Ocean, the International Union for the 

Conservation of Nature (IUCN) status is 

provided. The IUCN systematically 

assesses the relative risk of extinction 

for terrestrial and aquatic plant and 

animal species via a classification 

scheme using five designations, 

including three threatened categories 

(Critically Endangered, Endangered, and 

Vulnerable) and two non-threatened 

categories (Near Threatened and Least 

Concern) (www.iucnredlist.org/; 

accessed June 10, 2021). These 

assessments are generally made relative 

to the species’ global status, and 

therefore may have limited applicability 

when marine mammal stocks are 

defined because we analyze the 

potential population-level effects of the 

specified activity to the relevant stock. 

However, where stocks are not defined, 

IUCN status can provide a useful 

reference. 

TABLE 4—MARINE MAMMALS POTENTIALLY PRESENT IN THE VICINITY OF THE PROJECT AREA

Common name Scientific name Stock 2 ESA/MMPA/IUCN 

status 3 Abundance (CV) 4

Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales) 

Family Balaenidae (right whales): 

Southern right whale .................... Eubalaena australis ............................ ..................................... E/D/LC 1,755 (0.62).5

Family Balaenopteridae (rorquals): 

Humpback whale ......................... Megaptera novaeangliae australis ..... ..................................... E/D/LC 9,484 (0.28).5

Antarctic minke whale .................. Balaenoptera bonaerensis .................. ..................................... -/NT 18,125 (0.28).5

Fin whale ..................................... B. physalus quoyi ............................... ..................................... E/D/VU 4,672 (0.42).5

Blue whale ................................... B. musculus musculus ........................ ..................................... E/D/EN 1,700.13

Sei whale ..................................... Balaenoptera borealis ......................... ..................................... E/D/EN 626.14

Superfamily Odontoceti (toothed whales, dolphins, and porpoises) 

Family Physeteridae: 

Sperm whale ................................ Physeter macrocephalus .................... ..................................... E/D/VU 12,069 (0.17).7

Family Ziphiidae (beaked whales): 

Arnoux’s beaked whale ............... Berardius arnuxii ................................. ..................................... /DD Unknown. 

Southern bottlenose whale .......... Hyperoodon planifrons ....................... ..................................... -/LC 53,743 (0.12).8

Family Delphinidae: 

Hourglass dolphin ........................ Lagenorhynchus cruciger ................... ..................................... -/LC 144,300 (0.17).9

Killer whale .................................. Orcinus orca 1 ..................................... ..................................... -/DD 24,790 (0.23).8

Long-finned pilot whale ................ Globicephala melas edwardii ............. ..................................... -/LC 200,000 (0.35).9

Order Carnivora—Superfamily Pinnipedia 

Family Otariidae (eared seals and sea 

lions): 

Antarctic fur seal .......................... Arctocephalus gazella ........................ South Georgia ............ -/LC 2,700,000.10

Family Phocidae (earless seals): 

Southern elephant seal ................ Mirounga leonina ................................ South Georgia ............ -/LC 401,572.11

Weddell seal ................................ Leptonychotes weddellii ..................... ..................................... -/LC 500,000–1,000,000.12

Crabeater seal ............................. Lobodon carcinophaga ....................... ..................................... -/LC 5,000,000–10,000,000.12

Leopard seal ................................ Hydrurga leptonyx .............................. ..................................... -/LC 222,000–440,000.12

1Three distinct forms of killer whale have been described from Antarctic waters; referred to as types A, B, and C, they are purported prey specialists on Antarctic 

minke whales, seals, and fish, respectively (Pitman and Ensor, 2003; Pitman et al., 2010). 2For most species in the AMLR, stocks are not delineated and entries refer generally to individuals of the species occurring in the research area. 


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46204 Federal Register / Vol. 86, No. 157 / Wednesday, August 18, 2021 / Notices 

3Endangered 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. Any species listed under the ESA is automatically designated under the MMPA as depleted. IUCN status: Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD). 4 CV is coefficient of variation. All abundance estimates, except for those from Reilly et al., (2004) (right, humpback, minke, and fin whales), are for entire Southern 

Ocean (i.e., waters south of 60°S) and not the smaller area comprising the Southwest Fisheries Science Center (SWFSC) research area. 5Abundance estimates reported in Reilly et al., (2004) for the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) survey area from 

2000. Surveys include Antarctic Peninsula (473,300 km2) and Scotia Sea (1,109,800 km2) strata, which correspond roughly to SWFSC’s Antarctic Research Area 

(ARA), as reported by Hewitt et al., (2004). 6Southern Ocean abundance estimate (Branch et al., 2007). 7Southern Ocean abundance estimate (IWC, 2001 in Whitehead, 2002). 

8Southern Ocean abundance estimate from circumpolar surveys covering 68 percent of waters south of 60°S from 1991–98 (Branch and Butterworth, 2001). 9Southern Ocean abundance estimate derived from surveys conducted from 1976–88 (Kasamatsu and Joyce, 1995). 

10South Georgia abundance estimate; likely >95 percent of range-wide abundance (Forcada and Staniland, 2009). Genetic evidence shows two distinct population 

regions, likely descended from surviving post-sealing populations at South Georgia, Bouvet<ya, and Kerguelen Islands (Wynen et al., 2000; Forcada and Staniland, 

2009). Individuals from the South Georgia population (including breeding populations at the South Orkney and South Shetland Islands, which are within the ARA) are 

likely to occur in the ARA. 11Four genetically distinct populations are recognized: the Peninsula Valde ́s population in Argentina, the South Georgia population in the South Atlantic Ocean, the 

Kerguelen population in the South Indian Ocean and the Macquarie population in the South Pacific Ocean (Slade et al., 1998; Hoelzel et al., 2001). Animals occurring 

in ARA are likely to belong to South Georgia population, which includes subpopulations at South Georgia Island (>99 percent of population) and at the South Orkney 

and South Shetland Islands; South Georgia population abundance estimate from 2001 (McMahon et al., 2005). 12 Range-wide abundance estimates (Thomas and Terhune, 2009; Bengtson, 2009; Rogers, 2009). 13Southern Ocean abundance estimate (Branch et al., 2007). CI is confidence interval. 14South of 60°S. 

Antarctic Minke Whale 

Antarctic minke whales are similar in 

shape and coloration to the more global 

species of minke whale (B. 

acutorostrata). The two species differ in 

relative size and shape of several cranial 

features, and Antarctic minke whales 

lack the distinct white flipper mark of 

the more common minke whale. 

The seasonal distribution and 

migration patterns of nearly all 

populations of minke whales are poorly 

understood (Risch et al., 2019). 

Antarctic minke whales are abundant 

from 60°S to the ice edge during the 

austral summer then retreat in the 

austral winter to breeding grounds in 

mid-latitudes in the Pacific and other 

locations off Australia and South Africa. 

Antarctic minke feed mainly on 

euphausiids (krill (Euphausia superba)). 

This species is highly associated with 

sea ice and is generally less abundant in 

ice-free waters. In general, minke 

whales are commonly observed alone or 

in small groups of two or three 

individuals. Aggregations of up to 400 

may form on occasion in high latitudes. 

During the feeding season, mature 

females are found closer to the ice than 

immature females, and immature males 

are more solitary than mature males. 

Over the period January 21, 2019 

through March 31, 2020, one minke 

whale was observed during bird 

observation studies at Palmer Station in 

Arthur Harbor, which is on the other 

side of the peninsula separated from 

Hero Inlet. The whale was observed 

feeding about 300 m offshore. A lead 

Principal Investigator studying marine 

mammals as part of the Long-Term 

Ecological Research Program at Palmer 

Station notes minke whales are common 

within a few miles of the station (Ari 

Friedlander, personal communication). 

Fin Whale 

Fin whales are closely related to blue 

and sei whales. Northern and southern 

populations remain separated leading to 

genetic isolation of the populations. The 

fin whale is found in most large water 

masses of the world, from tropical to 

polar regions. However, in the most 

extreme latitudes individuals may be 

absent near the ice limit. Overall, fin 

whale densities in the southern 

hemisphere tend to be higher outside 

the continental slope than inside it. 

Fin whales feed on an assortment of 

prey items, depending on their 

availability (Kawamura 1980; as cited in 

Wursig et al., 2018); their diet varies 

with season and locality. Southern 

Hemisphere fin whales have a diet of 

almost exclusively krill, and other 

planktonic crustaceans. In the Southern 

Hemisphere, fin whales seasonally 

migrate north to south; they feed in the 

summer at high latitudes and breed and 

fast in the winter at low latitudes. 

One fin whale was recently seen 

within a few miles of the station (Ari 

Friedlander, personal communication). 

Blue Whale 

Blue whales in the Southern 

Hemisphere are on average larger than 

those in the Northern Hemisphere. Blue 

whales are a cosmopolitan species with 

North Atlantic, North Pacific, and 

Southern hemisphere populations. They 

were historically most abundant in the 

Southern Ocean, but are very rare today 

in the Project Area. Due to food 

availability they are found 

predominantly offshore. Blue whales 

feed almost exclusively on euphausiids 

in areas of cold water upwelling. 

Sei Whale 

Sei whales inhabit all ocean basins; 

they are oceanic and not commonly 

found in shelf seas. Sei whales migrate 

seasonally, spending the summer 

months feeding in the subpolar higher 

latitudes and returning to the lower 

latitudes to calve in winter. In the 

Southern Hemisphere, they are rarely 

found as far south as blue, fin, and 

minke whales, with summer 

concentrations mainly between the 

subtropical and Antarctic convergences 

(between 40°S and 50°S). Sei feed on 

copepods, euphausiids, shoals of fish, 

and squid if they are encountered. 

Hourglass Dolphin 

Hourglass dolphins are pelagic and 

circumpolar in the Southern Ocean; 

they are found in Antarctic and subAntarctic waters. Most sightings of live 

hourglass dolphins reflect observer 

effort, and are centered on the Antarctic 

convergence with most sightings from 

the Drake Passage. Hourglass dolphins 

often feed in large aggregations of 

seabirds such as great shearwaters and 

black-browed albatrosses, and in 

plankton slicks (White et al., 1999; as 

cited in Wursig et al., 2018). Their prey 

items include small fish (about 2.4 g and 

a length of 55 mm), small squid, and 

crustaceans. They are believed to feed in 

surface waters. 

Migratory movements of this species 

are not well known. It is thought that 

hourglass dolphins from the Antarctic 

convergence zone and the continental 

shelf break may move into sub-Antarctic 

waters in winter. Thus, the range of the 

species thus probably shifts north and 

south with the seasons (Carwardine 

1995; as cited in Wursig et al., 2018). 

Although oceanic, hourglass dolphins 

are often observed near islands and 

banks, in areas with turbulent waters; 

they have been observed in the Project 

Area (Ari Friedlander, personal 

communication). 

Humpback Whale 

Humpback whales are distributed 

throughout the world. They are highly 

migratory, spending spring through fall 

on feeding grounds in mid- or highlatitude waters, and wintering on 

calving grounds in the tropics, where 

they do not eat (Dawbin 1966; as 

referenced in Wursig et al., 2018). Seven 

populations of humpback whales are 


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found in the Southern hemisphere and 

feed throughout the waters off 

Antarctica. In the Southern Hemisphere, 

humpback whales feed in circumpolar 

waters and migrate to breeding grounds 

in tropical waters to the north. Seven 

breeding populations are recognized by 

the International Whaling Commission 

in the Southern Hemisphere, and these 

are linked to six feeding areas in the 

Antarctic. Bettridge et al., (2015) 

identify the southeast Pacific breeding 

stock as feeding in waters to the west of 

the Antarctic Peninsula where Palmer 

station is located. These animals breed 

in the Pacific-Central America waters. 

Humpback whales are considered 

generalists, feeding on euphausiids and 

various species of small schooling fish. 

They appear to be unique among large 

whales in their use of bubbles to corral 

or trap these schooling fish. 

Humpback whales are the most 

common whale seen within a few miles 

of the station (Ari Friedlander, personal 

communication). From January 21, 2019 

through March 31, 2020, marine 

mammal sightings have been recorded 

during bird observation studies at 

Palmer Station. On January 23, 2019, 

three humpback whales (two adults and 

one juvenile) were observed feeding off 

Torgersen Island, and one adult and one 

juvenile were observed feeding in 

Arthur Harbor on January 26, 2019. 

Several groups of up to four individuals 

(likely adults and juveniles) were 

observed feeding in Arthur Harbor in 

early February 2019. No humpbacks 

were observed after February 12. At the 

end of May 2019, two humpback whales 

were again observed near Bonaparte 

Point, with no other sightings until the 

end of December 2019 when one 

humpback was observed feeding in 

Arthur Harbor. In late December 2019 

through early February 2020, individual 

whales or groups of two adults and 

possibly a juvenile feeding in Arthur 

Harbor were recorded on 10 separate 

occasions. A large group of five whales 

(four adults and a juvenile) was 

observed in Arthur Harbor on March 3, 

2020. This was the last sighting 

recorded. 

Killer Whale 

The killer whale is found in all the 

world’s oceans and most seas. It is the 

largest member of the family 

Delphinidae and has very distinctive 

black-and-white coloration. Antarctic 

killer whales make periodic rapid longdistance migrations to subtropical 

waters, possibly for skin maintenance 

(Durban and Pitman 2011; as referenced 

in Wursig et al., 2018). Killer whales are 

social animals that are usually observed 

traveling in groups containing a few to 

20 or more individuals. Reports of larger 

groups usually involve temporary 

aggregations of smaller, more stable 

social units. 

Currently only one species of killer 

whale is recognized (O. orca), but it is 

likely that some of genetically distinct 

forms found in different regions of the 

world represent distinct species (Wursig 

et al., 2018). In the Antarctic, five 

distinct forms of killer whale have been 

identified: Types A, B1, B2, C, and D. 

They differ in coloration, morphology, 

and in some cases diet (Pitman and 

Ensor 2003). Types B1 and B2 are the 

most common form observed around the 

Antarctic Peninsula and Anvers Island 

(Durban et al., 2016). 

Killer whales prey on a wide range of 

vertebrates and invertebrates; they have 

no natural predators other than humans. 

It is the only cetacean that routinely 

preys upon marine mammals, with 

attacks or kills documented for 50 

different species. Mammalian taxa that 

are prey of killer whales include other 

cetaceans—both mysticetes and 

odontocetes—pinnipeds, sirenians, 

mustelids and, on rare occasions, 

ungulates. A variety of fish species are 

also important food of killer whales. In 

the Antarctic, killer whales in open 

water prey on Antarctic minke whales, 

seals, and fish. 

Killer whales are commonly observed 

within a few miles of the station (Ari 

Friedlander, personal communication). 

Long-Finned Pilot Whale 

Long-finned pilot whales inhabit the 

cold temperate waters of both the North 

Atlantic and the Southern Ocean. They 

are circumpolar in the Southern 

Hemisphere and occur as far north as 

14°S in the Pacific and south to the 

Antarctic Convergence (Olson 2009). 

Pilot whales are found in both nearshore 

and pelagic environments. Pilot whales 

are generally nomadic, but are highly 

social and are usually observed in 

schools of several to hundreds of 

animals. They also have been observed 

in mixed species aggregations. Their 

diet consists mostly of squid and other 

cephalopods, with smaller amounts of 

fish. Pilot whales are known to dive 

deep for prey; the maximum dive depth 

measured is about 1,000 m. 

Arnoux’s Beaked Whale 

Arnoux’s beaked whales inhabit vast 

areas of the Southern Hemisphere, 

between 24°S and Antarctica. They are 

a deep diving species and can be found 

in areas of heavy ice cover. Little is 

known of the diet of Arnoux’s beaked 

whales but one individual’s stomach 

was found to be mostly filled with squid 

beaks (Wursig et al. 2018). Arnoux’s 

beaked whales often occur in groups of 

6–10 and occasionally up to 50 or more 

(Balcomb 1989). Arnoux’s beaked 

whales have been observed in the 

Project area. Because they are heavily 

ice-associated Arnoux’s, beaked whales 

may be directly affected by loss of sea 

ice due to climate change. 

Southern Bottlenose Whale 

Southern bottlenose whales are 

widely distributed throughout the 

Southern Hemisphere, mainly south of 

30°S, and are most common between 

58°S and 62°S. Bottlenose whales seem 

to prefer deeper waters and, like other 

beaked whales, they make regular deep 

dives to forage. Stomach content 

analyses of six southern bottlenose 

whales show that this species feeds 

primarily on squid (MacLeod et al., 

2003). Bottlenose whales are typically 

observed in small groups of up to 10 

individuals, though groups of up to 20 

animals of mixed age/sex classes have 

been reported. Social behaviors have not 

been studied in southern bottlenose 

whales. 

Southern Right Whale 

Southern right whales are found 

between 20°S and 60°S. Right whales 

are ‘‘skimmers’’ (Baumgartner et al., 

2007; as cited in Wursig et al., 2018). 

They feed offshore in pelagic regions in 

areas of high productivity by swimming 

forward with the mouth agape. Feeding 

can occur at or just below the surface, 

where it can be observed easily, or at 

depth. At times, right whales apparently 

feed very close to the bottom, because 

they are observed to surface at the end 

of an extended dive with mud on their 

heads. Typical feeding dives last for 10– 

20 min. It is likely that krill comprise a 

high proportion of the diet in southern 

right whales. 

Sperm Whale 

Sperm whales are widely distributed, 

but distribution of the sexes are 

different. Female sperm whales almost 

always inhabit water deeper than 1,000 

m and at latitudes less than 40°S, 

corresponding roughly to sea surface 

temperatures greater than 15°C. Sperm 

whales dive to about 600 m below the 

surface where they hunt primarily for 

squid. Distribution and relative 

abundance can vary in response to prey 

availability, most notably squid (Jaquet 

& Gendron 2002). 

Large males from high latitudes can 

be found in almost any ice-free deep 

water. Therefore, any sperm whales 

encountered in Antarctic waters are 

highly likely to be male. They are more 

likely to be sighted in productive 

waters, such as those along the edges of 


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continental shelves. Sperm whales have 

low birth rates, slow growth and high 

survival rates. 

Antarctic Fur Seal 

Antarctic fur seals have a circumpolar 

distribution. They are found from the 

Antarctic continent to the Falkland 

Islands. Land-based breeding strongly 

influences the distribution of females 

and their foraging ecology. Lactating 

females are restricted to foraging in the 

waters immediately surrounding the 

breeding beaches, whereas males can 

disperse after mating. Female 

distribution expands after breeding as 

they leave rookeries. 

Antarctic krill dominates the diet of 

Antarctic fur seals in the vicinity of the 

Project Area. Penguins are occasionally 

taken by Antarctic fur seal bulls. Killer 

whales are likely the main predator of 

the species, but leopard seals are 

thought to limit the population growth 

at Elephant Island in the South Shetland 

Islands. Large bulls of other species also 

prey on pups where species coexist. 

Over three seasons from 2019 through 

2020 (i.e., two Antarctic summers and 

one winter), marine mammal sightings 

have been recorded during daily bird 

observation studies at Palmer Station. A 

total of 73 fur seals were observed either 

hauled out or swimming in Hero Inlet 

during the Antarctic summer months 

between January and March 2019. Over 

a longer summer period between 

October 2019 and March 2020, there 

were 242 seals observed in Hero Inlet, 

with the majority of seals hauled out 

(see Table 6–1 in application). During 

the winter months between March and 

October 2019, 70 seals were observed in 

Hero Inlet. Fewer fur seals were 

observed over the same 2019–2020 

months in Arthur Harbor. See Section 6 

of the application for additional details 

on seal observations in the project 

vicinity (NSF, personal 

communication). 

Crabeater Seal 

Crabeater seals have a circumpolar 

Antarctic distribution; they spend the 

entire year in pack ice. They move over 

large distances with the annual advance 

and retreat of pack ice. Although they 

can be found anywhere within the pack 

ice zone, they are typically found at the 

edge of the continental shelf, as well as 

in the marginal ice zone (Burns et al., 

2004 and Southwell et al., 2005; as 

referenced in Wursig et al., 2018). 

Crabeater seals sometimes congregate in 

large groups of up to several hundred, 

which might be associated with general 

patterns of seasonal movement or 

foraging. As with other Antarctic seals, 

crabeater seals have a daily haul out 

pattern in summer that generally 

involves hauling out on ice floes during 

the middle of the day (Bengtson and 

Cameron, 2004; as referenced in Wursig 

et al., 2018), though usually less than 80 

percent are hauled out on the ice at the 

same time. 

Antarctic krill is the primary prey 

item for crabeater seals, constituting 

over 95 percent of their diet. They also 

eat small quantities of fish and squid 

(;ritsland, 1977; as referenced in 

Wursig et al., 2018). Crabeater seals do 

not appear to seasonally switch prey. 

During daily nocturnal foraging periods 

in summer, crabeater seals will nearly 

continuously dive for up to 16 h at a 

time. 

Over three seasons (i.e., two Antarctic 

summers and one winter) from January 

21, 2019 through March 31, 2020, 

marine mammal sightings have been 

recorded during bird observation 

studies at Palmer Station. Crabeater 

seals were commonly observed 

individually or in small groups lying on 

the ice in Arthur Harbor and Hero Inlet 

in late January and February of 2019; 

the frequency of sightings decreased by 

March. Groups of up to four individuals 

were observed in or near the Project 

Area in early April of 2019, some were 

lying on the floating dock. Groups of 

crabeater seals were observed swimming 

in Hero Inlet near Gamage Point in April 

and early May of 2019. No crabeater 

seals were recorded in June, but in early 

July of 2019 groups of two seals and 

individuals were observed on the ice at 

Arthur Harbor and Hero Inlet, and on 

the shore at Bonaparte Point. No 

crabeater seals were observed from midJuly to mid-October of 2019. 

Observations of crabeater seals 

increased in Arthur Harbor frequency 

into November of 2019, with sightings 

continuing into December. However, 

from January of 2020 through March of 

2020, crabeater seals were only observed 

on nine occasions; this was less frequent 

than sightings recorded from January to 

March of 2019 (NSF, personal 

communication). 

Southern Elephant Seal 

Southern elephant seals are the largest 

of all pinnipeds. Southern elephant 

seals can be divided into three distinct 

stocks: Maguire Island, Iles Kerguelen, 

and South Georgia, the latter of which 

is relevant to the Project Area. There is 

some separation of feeding areas 

between the sexes, with males tending 

to feed more in continental shelf waters, 

while females either use ice-free waters 

broadly associated with the Antarctic 

Polar Front, or the marginal ice zone, 

moving northward as the ice expands. 

Elephant seals prey on deepwater and 

bottom dwelling organisms, including 

fish, squid, crab, and octopus. They are 

extraordinary divers with some dive 

depths exceeding 1,500 m and lasting 

up to 120 minutes. 

Over three seasons (two Antarctic 

summers and one winter) from January 

21, 2019 through March 31, 2020, one 

elephant seal was observed lying on 

shore near Palmer Station in early 

March of 2019. No other seals were 

observed again until October of 2019 

when on six days over the period 

October 8 to 19, 2019 a single seal was 

observed lying on the ice in Arthur 

Harbor. Additional sightings were noted 

in November and December 2019 in 

Hero Inlet. Sightings increased from 

January 6 to February 10, 2020, when 

elephant seals were observed at 

Bonaparte Point as individuals or in 

groups as large as 7 nearly every day 

and sometimes several times a day. No 

elephant seals were observed after 

February 10, 2020. This is noticeably 

different than 2019, when no elephant 

seals were observed in January or 

February (NSF, personal 

communication). 

Leopard Seal 

The leopard seal (Hydrurga leptonyx) 

is the largest Antarctic pack ice seal. 

Leopard seals are solitary pinnipeds, 

and are widely dispersed at low 

densities on the circumpolar Antarctic 

pack ice (Rogers et al., 2013; as cited in 

Wursig et al., 2018). Most of the leopard 

seal population remains within the pack 

ice, but when the sea ice extent is 

minimal, leopard seals are restricted to 

coastal habitats (Meade et al., 2015; as 

cited in Wursig et al., 2018). 

These seals prey on penguins, other 

marine mammals, and zooplankton; this 

combination of apex predator and 

planktivore is unique for marine 

mammals. Due to the size of their 

mouth, leopard seals can take largebodied prey including crabeater, 

Weddell, southern elephant seals, and 

fur seals. 

During three seasons (two Antarctic 

summers and one winter) of observation 

studies at Palmer Station, single leopard 

seals were occasionally observed lying 

on the ice in Arthur Harbor or 

swimming in Hero Inlet starting in late 

January until April of 2019. One 

additional sighting was recorded in July, 

and no leopard seals were observed 

again until November 19, 2019, when 

three were observed on the ice in Arthur 

Harbor. Occasional sightings continued 

from November 2019 through March of 

2020. On March 31, a leopard seal was 

observed feeding on a crabeater seal in 

Hero Inlet (NSF, personal 

communication). 


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Weddell Seal 

Weddell seals are large pinnipeds 

weighing up to 600 kg with typical 

weights between 300 and 500 kg. 

Weddell seals aggregate on the ice to 

molt, and also sporadically dive during 

this period. After molting in fall-winter 

these seals disperse to sea; some 

individuals remain within the vicinity 

of their colonies, whereas other 

individuals disperse several hundreds 

of kilometers away and may not return 

to their colonies for several weeks. 

The Weddell seal’s range includes 

coastal areas around the Antarctic 

continent and they are found in areas of 

both fast and pack ice. Weddell seals 

rarely venture into open, ice-free waters. 

Animals inhabiting the islands of the 

mostly ice-free northern Antarctic 

Peninsula are primarily coastal in their 

distribution. 

Weddell seals consume epipelagic (0– 

200 m), mesopelagic (200–1000 m) and 

benthic prey. They can dive to depths 

over 600 m to reach the deeper prey 

items. Their diet consists mainly of fish 

but they also eat cephalopods, decapods 

and Antarctic krill. Their feeding/haul 

out pattern is diurnal; they haulout 

during the day and forage at night in 

response to the vertical migration of 

their prey (Andrews-Goff et al., 2010; as 

cited in Wursig et al., 2018). 

Over three seasons (two Antarctic 

summers and one winter) of observation 

from January 21, 2019 through March 

31, 2020, individual Weddell seals were 

observed on shore at Bonaparte Point 

from the end of February of 2019 

through April of 2019. Weddell seals 

were observed swimming in Hero Inlet 

in early April 2019 on several occasions. 

No Weddell seals were sighted again 

until mid-September of 2019, when an 

individual was again observed on the 

ice in Hero Inlet. After September 16, 

2019, no Weddell seals were observed 

in the vicinity of Palmer Station until 

January 6, 2020; at that time a seal was 

observed in the vicinity of the outfall. 

As with 2019 observations, Weddell seal 

sightings at Bonaparte Pointe increased 

in mid- to late February of 2020, and 

continued every day or every few days 

through March 27, 2020. 

As indicated above, all 17 species in 

Table 4 temporally and spatially cooccur with the activity to the degree that 

take is reasonably likely to occur, and 

we have proposed authorizing it. 

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. Current data indicate 

that not all marine mammal species 

have equal hearing capabilities (e.g., 

Richardson et al., 1995; Wartzok and 

Ketten, 1999; Au and Hastings, 2008). 

To reflect this, Southall et al. (2007) 

recommended that marine mammals be 

divided into functional hearing groups 

based on directly measured or estimated 

hearing ranges on the basis of available 

behavioral response data, audiograms 

derived using auditory evoked potential 

techniques, anatomical modeling, and 

other data. No direct measurements of 

hearing ability have been successfully 

completed for mysticetes (i.e., lowfrequency cetaceans). Subsequently, 

NMFS (2018) described generalized 

hearing ranges for these marine mammal 

hearing groups. Generalized hearing 

ranges were chosen based on the 

approximately 65 decibel (dB) threshold 

from the normalized composite 

audiograms, with the exception for 

lower limits for low-frequency 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 5. 

TABLE 5—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 16 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. Of the seventeen 

marine mammal species that may be 

present, six are classified as lowfrequency cetaceans (i.e., all mysticete 

species), five are classified as midfrequency cetaceans (i.e., all delphinid 

and ziphiid species and the sperm 

whale), one is classified as a highfrequency cetacean species (i.e., 

hourglass dolphin.) and there is one 

species of otariid and 4 phocids. 

Potential Effects of Specified Activities 

on Marine Mammals and Their Habitat 

This section includes a summary and 

discussion of the ways that components 

of the specified activity may impact 

marine mammals and their habitat. The 

Estimated Take section later in this 

document includes a quantitative 

analysis of the number of individuals 

that are expected to be taken by this 

activity. The Negligible Impact Analysis 

and Determination section considers the 

content of this section, the Estimated 

Take section, and the Proposed 

Mitigation section, to draw conclusions 

regarding the likely impacts of these 

activities on the reproductive success or 

survivorship of individuals and how 

those impacts on individuals are likely 

to impact marine mammal species or 

stocks. 

Acoustic effects on marine mammals 

during the specified activity can occur 

from the underwater noise resulting 

from DTH pile installation, vibratory 

hammer removal, limited impact 

driving to seat piles, rock chipping, and 

the use of a hydrogrinder. The effects of 

underwater noise from NSF’s proposed 

activities have the potential to result in 


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Level A or Level B harassment of marine 

mammals in the Project Area. 

Description of Sound Sources 

The primary relevant stressor to 

marine mammals from the proposed 

activity is the introduction of noise into 

the aquatic environment; therefore, we 

focus our impact analysis on the effects 

of anthropogenic noise on marine 

mammals. To better understand the 

potential impacts, we describe sound 

source characteristics below. 

Specifically, we look at the following 

two ways to characterize sound: By its 

temporal (i.e., continuous or 

intermittent) and its pulse (i.e., 

impulsive or non-impulsive) properties. 

Continuous sounds are those whose 

sound pressure level remains above that 

of the ambient sound, with negligibly 

small fluctuations in level (NIOSH, 

1998; ANSI, 2005), while intermittent 

sounds are defined as sounds with 

interrupted levels of low or no sound 

(NIOSH, 1998). Impulsive sounds, such 

as those generated by impact pile 

driving, are typically transient, brief (< 

1 sec), broadband, and consist of a high 

peak pressure with rapid rise time and 

rapid decay (ANSI, 1986; NIOSH, 1998). 

The majority of energy in pile impact 

pulses is at frequencies below 500 hertz 

(Hz). Impulsive sounds, by definition, 

are intermittent. Non-impulsive sounds, 

such as those generated by vibratory 

pile removal can be broadband, 

narrowband or tonal, brief or prolonged, 

and typically do not have a high peak 

sound pressure with rapid rise/decay 

time that impulsive sounds do (ANSI, 

1995; NIOSH, 1998). Non-impulsive 

sounds can be intermittent or 

continuous. Similar to impact pile 

driving, vibratory pile driving generates 

low frequency sounds. Vibratory pile 

driving is considered a non-impulsive, 

continuous source. DTH is a hybrid 

source- the rotary drill action produces 

non-impulsive, continuous sounds 

while the hammer function produces 

impulsive sounds. Discussion on the 

appropriate harassment threshold 

associated with these types of sources 

based on these characteristics can be 

found in the Estimated Take section. 

Potential Effects of Pile Driving 

In general, the effects of sounds from 

pile driving to marine mammals might 

result in one or more of the following: 

Temporary or permanent hearing 

impairment, non-auditory physical or 

physiological effects, behavioral 

disturbance, and masking (Richardson 

et al., 1995; Nowacek et al., 2007; 

Southall et al., 2007). The potential for 

and magnitude of these effects are 

dependent on several factors, including 

receiver characteristics (e.g., age, size, 

depth of the marine mammal receiving 

the sound during exposure); the energy 

needed to drive the pile (usually related 

to pile size, depth driven, and 

substrate), the standoff distance between 

the pile and receiver; and the sound 

propagation properties of the 

environment. 

Impacts to marine mammals from pile 

driving activities are expected to result 

primarily from acoustic pathways. As 

such, the degree of effect is intrinsically 

related to the received level and 

duration of the sound exposure, which 

are in turn influenced by the distance 

between the animal and the source. The 

further away from the source, the less 

intense the exposure should be. The 

type of pile driving also influences the 

type of impacts, for example, exposure 

to impact pile driving or DTH may 

result in temporary or permanent 

hearing impairment, while auditory 

impacts are unlikely to result from 

exposure to vibratory pile driving. The 

substrate and depth of the habitat affect 

the sound propagation properties of the 

environment. Shallow environments are 

typically more structurally complex, 

which leads to rapid sound attenuation. 

In addition, substrates that are soft (e.g., 

sand) absorb or attenuate the sound 

more readily than hard substrates (e.g., 

rock) which may reflect the acoustic 

wave. Soft porous substrates also likely 

require less time to drive the pile, and 

possibly less forceful equipment, which 

ultimately decrease the intensity of the 

acoustic source. 

Richardson et al. (1995) described 

zones of increasing intensity of effect 

that might be expected to occur, in 

relation to distance from a source and 

assuming that the signal is within an 

animal’s hearing range. First is the area 

within which the acoustic signal would 

be audible (potentially perceived) to the 

animal, but not strong enough to elicit 

any overt behavioral or physiological 

response. The next zone corresponds 

with the area where the signal is audible 

to the animal and of sufficient intensity 

to elicit behavioral or physiological 

responsiveness. Third is a zone within 

which, for signals of high intensity, the 

received level is sufficient to potentially 

cause discomfort or tissue damage to 

auditory or other systems. Overlaying 

these zones to a certain extent is the 

area within which masking (i.e., when a 

sound interferes with or masks the 

ability of an animal to detect a signal of 

interest that is above the absolute 

hearing threshold) may occur; the 

masking zone may be highly variable in 

size. 

NMFS defines a noise-induced 

threshold shift (TS) as ‘‘a change, 

usually an increase, in the threshold of 

audibility at a specified frequency or 

portion of an individual’s hearing range 

above a previously established reference 

level’’ (NMFS, 2016b). The amount of 

threshold shift is customarily expressed 

in dB (ANSI 1995, Yost 2007). A TS can 

be permanent (PTS) or temporary (TTS). 

As described in NMFS (2018), there are 

numerous factors to consider when 

examining the consequence of TS, 

including, but not limited to, the signal 

temporal pattern (e.g., impulsive or nonimpulsive), likelihood an individual 

would be exposed for a long enough 

duration or to a high enough level to 

induce a TS, the magnitude of the TS, 

time to recovery (seconds to minutes or 

hours to days), the frequency range of 

the exposure (i.e., spectral content), the 

hearing and vocalization frequency 

range of the exposed species relative to 

the signal’s frequency spectrum (i.e., 

how animal uses sound within the 

frequency band of the signal; e.g., 

Kastelein et al., 2014), and the overlap 

between the animal and the source (e.g., 

spatial, temporal, and spectral). 

Permanent Threshold Shift— NMFS 

defines PTS as a permanent, irreversible 

increase in the threshold of audibility at 

a specified frequency or portion of an 

individual’s hearing range above a 

previously established reference level 

(NMFS, 2018). Available data from 

humans and other terrestrial mammals 

indicate that a 40 dB threshold shift 

approximates PTS onset (see NMFS 

2018 for review). 

Temporary Threshold Shift—NMFS 

defines TTS as a temporary, reversible 

increase in the threshold of audibility at 

a specified frequency or portion of an 

individual’s hearing range above a 

previously established reference level 

(NMFS, 2018). Based on data from 

cetacean TTS measurements (see 

Finneran 2015 for a review), a TTS of 

6 dB is considered the minimum 

threshold shift clearly larger than any 

day-to-day or session-to-session 

variation in a subject’s normal hearing 

ability (Schlundt et al., 2000; Finneran 

et al., 2000; Finneran et al., 2002). As 

described in Finneran (2016), marine 

mammal studies have shown the 

amount of TTS increases with 

cumulative sound exposure level 

(SELcum) in an accelerating fashion: At 

low exposures with lower SELcum, the 

amount of TTS is typically small and 

the growth curves have shallow slopes. 

At exposures with higher SELcum, the 

growth curves become steeper and 

approach linear relationships with the 

noise SEL. 

Depending on the degree (elevation of 

threshold in dB), duration (i.e., recovery 

time), and frequency range of TTS, and 


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the context in which it is experienced, 

TTS can have effects on marine 

mammals ranging from discountable to 

serious (similar to those discussed in 

auditory masking, below). For example, 

a marine mammal may be able to readily 

compensate for a brief, relatively small 

amount of TTS in a non-critical 

frequency range that takes place during 

a time when the animal is traveling 

through the open ocean, where ambient 

noise is lower and there are not as many 

competing sounds present. 

Alternatively, a larger amount and 

longer duration of TTS sustained during 

time when communication is critical for 

successful mother/calf interactions 

could have more serious impacts. We 

note that reduced hearing sensitivity as 

a simple function of aging has been 

observed in marine mammals, as well as 

humans and other taxa (Southall et al., 

2007), so we can infer that strategies 

exist for coping with this condition to 

some degree, though likely not without 

cost. 

Schlundt et al. (2000) performed a 

study exposing five bottlenose dolphins 

and two beluga whales (same 

individuals as Finneran’s studies) to 

intense one second tones at different 

frequencies. The resulting levels of 

fatiguing stimuli necessary to induce 6 

dB or larger masked TTSs were 

generally between 192 and 201 dB re: 1 

microPascal (mPa). Dolphins began to 

exhibit altered behavior at levels of 178– 

193 dB re: 1 m Pa and above; beluga 

whales displayed altered behavior at 

180–196 dB re: 1 m Pa and above. At the 

conclusion of the study, all thresholds 

were at baseline values. 

There are a limited number of studies 

investigating the potential for cetacean 

TTS from pile driving and only one has 

elicited a small amount of TTS in a 

single harbor porpoise individual 

(Kastelein et al., 2015). However, 

captive bottlenose dolphins and beluga 

whales have exhibited changes in 

behavior when exposed to pulsed 

sounds (Finneran et al., 2000, 2002, and 

2005). The animals tolerated high 

received levels of sound before 

exhibiting aversive behaviors. 

Experiments on a beluga whale showed 

that exposure to a single watergun 

impulse at a received level of 207 

kiloPascal (kPa) (30 psi) p-p, which is 

equivalent to 228 dB p-p, resulted in a 

7 and 6 dB TTS in the beluga whale at 

0.4 and 30 kHz, respectively. 

Thresholds returned to within 2 dB of 

the pre-exposure level within four 

minutes of the exposure (Finneran et al., 

2002). Although the source level of pile 

driving from one hammer strike is 

expected to be lower than the single 

watergun impulse cited here, animals 

being exposed for a prolonged period to 

repeated hammer strikes could receive 

more sound exposure in terms of SEL 

than from the single watergun impulse 

(estimated at 188 dB re 1 mPa2-s) in the 

aforementioned experiment (Finneran et 

al., 2002). Results of these studies 

suggest odontocetes are susceptible to 

TTS from pile driving, but that they 

seem to recover quickly from at least 

small amounts of TTS. 

Behavioral Responses—Behavioral 

disturbance may include a variety of 

effects, including subtle changes in 

behavior (e.g., minor or brief avoidance 

of an area or changes in vocalizations), 

more conspicuous changes in similar 

behavioral activities, and more 

sustained and/or potentially severe 

reactions, such as displacement from or 

abandonment of high-quality habitat. 

Disturbance may result in changing 

durations of surfacing and dives, 

number of blows per surfacing, or 

moving direction and/or speed; 

reduced/increased vocal activities; 

changing/cessation of certain behavioral 

activities (such as socializing or 

feeding); visible startle response or 

aggressive behavior (such as tail/fluke 

slapping or jaw clapping); avoidance of 

areas where sound sources are located. 

Pinnipeds may increase their haul out 

time, possibly to avoid in-water 

disturbance (Thorson and Reyff, 2006). 

Behavioral responses to sound are 

highly variable and context-specific and 

any reactions depend on numerous 

intrinsic and extrinsic factors (e.g., 

species, state of maturity, experience, 

current activity, reproductive state, 

auditory sensitivity, time of day), as 

well as the interplay between factors 

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

al., 2003; Southall et al., 2007; Weilgart, 

2007; Archer et al., 2010). Behavioral 

reactions can vary not only among 

individuals but also within an 

individual, depending on previous 

experience with a sound source, 

context, and numerous other factors 

(Ellison et al., 2012), and can vary 

depending on characteristics associated 

with the sound source (e.g., whether it 

is moving or stationary, number of 

sources, distance from the source). In 

general, pinnipeds seem more tolerant 

of, or at least habituate more quickly to, 

potentially disturbing underwater sound 

than do cetaceans, and generally seem 

to be less responsive to exposure to 

industrial sound than most cetaceans. 

Please see Appendices B–C of Southall 

et al., (2007) for a review of studies 

involving marine mammal behavioral 

responses to sound. 

Habituation can occur when an 

animal’s response to a stimulus wanes 

with repeated exposure, usually in the 

absence of unpleasant associated events 

(Wartzok et al., 2003). Animals are most 

likely to habituate to sounds that are 

predictable and unvarying. It is 

important to note that habituation is 

appropriately considered as a 

‘‘progressive reduction in response to 

stimuli that are perceived as neither 

aversive nor beneficial,’’ rather than as, 

more generally, moderation in response 

to human disturbance (Bejder et al., 

2009). The opposite process is 

sensitization, when an unpleasant 

experience leads to subsequent 

responses, often in the form of 

avoidance, at a lower level of exposure. 

As noted above, behavioral state may 

affect the type of response. For example, 

animals that are resting may show 

greater behavioral change in response to 

disturbing sound levels than animals 

that are highly motivated to remain in 

an area for feeding (Richardson et al., 

1995; NRC, 2003; Wartzok et al., 2003). 

Controlled experiments with captive 

marine mammals have showed 

pronounced behavioral reactions, 

including avoidance of loud sound 

sources (Ridgway et al., 1997; Finneran 

et al., 2003). Observed responses of wild 

marine mammals to loud pulsed sound 

sources (typically seismic airguns or 

acoustic harassment devices) have been 

varied but often consist of avoidance 

behavior or other behavioral changes 

suggesting discomfort (Morton and 

Symonds 2002; see also Richardson et 

al., 1995; Nowacek et al., 2007). 

Available studies show wide variation 

in marine mammal response to 

underwater sound; therefore, it is 

difficult to predict specifically how any 

given sound in a particular instance 

might affect marine mammals 

perceiving the signal. If a marine 

mammal does react briefly to an 

underwater sound by changing its 

behavior or moving a small distance, the 

impacts of the change are unlikely to be 

significant to the individual, let alone 

the stock or population. However, if a 

sound source displaces marine 

mammals from an important feeding or 

breeding area for a prolonged period, 

impacts on individuals and populations 

could be significant (e.g., Lusseau and 

Bejder, 2007; Weilgart, 2007; NRC, 

2005). There are broad categories of 

potential response, which we describe 

in greater detail here, that include 

alteration of dive behavior, alteration of 

foraging behavior, effects to breathing, 

interference with or alteration of 

vocalization, avoidance, and flight. 

Changes in dive behavior can vary 

widely and may consist of increased or 

decreased dive times and surface 

intervals as well as changes in the rates 

of ascent and descent during a dive (e.g., 


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Frankel and Clark, 2000; Costa et al., 

2003; Ng and Leung, 2003; Nowacek et 

al., 2004; Goldbogen et al., 2013a,b). 

Variations in dive behavior may reflect 

interruptions in biologically significant 

activities (e.g., foraging) or they may be 

of little biological significance. The 

impact of an alteration to dive behavior 

resulting from an acoustic exposure 

depends on what the animal is doing at 

the time of the exposure and the type 

and magnitude of the response. 

Disruption of feeding behavior can be 

difficult to correlate with anthropogenic 

sound exposure, so it is usually inferred 

by observed displacement from known 

foraging areas, the appearance of 

secondary indicators (e.g., bubble nets 

or sediment plumes), or changes in dive 

behavior. As for other types of 

behavioral response, the frequency, 

duration, and temporal pattern of signal 

presentation, as well as differences in 

species sensitivity, are likely 

contributing factors to differences in 

response in any given circumstance 

(e.g., Croll et al., 2001; Nowacek et al., 

2004; Madsen et al., 2006; Yazvenko et 

al., 2007). A determination of whether 

foraging disruptions incur fitness 

consequences would require 

information on or estimates of the 

energetic requirements of the affected 

individuals and the relationship 

between prey availability, foraging effort 

and success, and the life history stage of 

the animal. 

Respiratory variations with different 

behaviors and alterations to breathing 

rate as a function of acoustic exposure 

can be expected to co-occur with other 

behavioral reactions, such as a flight 

response or an alteration in diving. 

However, respiration rates in and of 

themselves may be representative of 

annoyance or an acute stress response. 

Various studies have shown that 

respiration rates may either be 

unaffected or could increase, depending 

on the species and signal characteristics, 

again highlighting the importance in 

understanding species differences in the 

tolerance of underwater noise when 

determining the potential for impacts 

resulting from anthropogenic sound 

exposure (e.g., Kastelein et al., 2001, 

2005b, 2006; Gailey et al., 2007). 

Marine mammals vocalize for 

different purposes and across multiple 

modes, such as whistling, echolocation 

click production, calling, and singing. 

Changes in vocalization behavior in 

response to anthropogenic noise can 

occur for any of these modes and may 

result from a need to compete with an 

increase in background noise or may 

reflect increased vigilance or a startle 

response. For example, in the presence 

of potentially masking signals, 

humpback whales and killer whales 

have been observed to increase the 

length of their songs (Miller et al., 2000; 

Fristrup et al., 2003; Foote et al., 2004), 

while North Atlantic right whales 

(Eubalaena glacialis) have been 

observed to shift the frequency content 

of their calls upward while reducing the 

rate of calling in areas of increased 

anthropogenic noise (Parks et al., 2007). 

In some cases, animals may cease sound 

production during production of 

aversive signals (Bowles et al., 1994). 

Avoidance is the displacement of an 

individual from an area or migration 

path as a result of the presence of a 

sound or other stressors, and is one of 

the most obvious manifestations of 

disturbance in marine mammals 

(Richardson et al., 1995). For example, 

gray whales are known to change 

direction—deflecting from customary 

migratory paths—in order to avoid noise 

from seismic surveys (Malme et al., 

1984). Avoidance may be short-term, 

with animals returning to the area once 

the noise has ceased (e.g., Bowles et al., 

1994; Goold, 1996; Morton and 

Symonds, 2002; Gailey et al., 2007). 

Longer-term displacement is possible, 

however, which may lead to changes in 

abundance or distribution patterns of 

the affected species in the affected 

region if habituation to the presence of 

the sound does not occur (e.g., 

Blackwell et al., 2004; Bejder et al., 

2006; Teilmann et al., 2006). 

A flight response is a dramatic change 

in normal movement to a directed and 

rapid movement away from the 

perceived location of a sound source. 

The flight response differs from other 

avoidance responses in the intensity of 

the response (e.g., directed movement, 

rate of travel). Relatively little 

information on flight responses of 

marine mammals to anthropogenic 

signals exist, although observations of 

flight responses to the presence of 

predators have occurred (Connor and 

Heithaus, 1996). The result of a flight 

response could range from brief, 

temporary exertion and displacement 

from the area where the signal provokes 

flight to, in extreme cases, marine 

mammal strandings (Evans and 

England, 2001). However, it should be 

noted that response to a perceived 

predator does not necessarily invoke 

flight (Ford and Reeves, 2008), and 

whether individuals are solitary or in 

groups may influence the response. 

Behavioral disturbance can also 

impact marine mammals in more subtle 

ways. Increased vigilance may result in 

costs related to diversion of focus and 

attention (i.e., when a response consists 

of increased vigilance, it may come at 

the cost of decreased attention to other 

critical behaviors such as foraging or 

resting). These effects have generally not 

been demonstrated for marine 

mammals, but studies involving fish 

and terrestrial animals have shown that 

increased vigilance may substantially 

reduce feeding rates (e.g., Beauchamp 

and Livoreil 1997; Fritz et al, 2002; 

Purser and Radford, 2011). In addition, 

chronic disturbance can cause 

population declines through reduction 

of fitness (e.g., decline in body 

condition) and subsequent reduction in 

reproductive success, survival, or both 

(e.g., Harrington and Veitch, 1992; Daan 

et al., 1996; Bradshaw et al., 1998). 

However, Ridgway et al., (2006) 

reported that increased vigilance in 

bottlenose dolphins exposed to sound 

over a five-day period did not cause any 

sleep deprivation or stress effects. 

Many animals perform vital functions, 

such as feeding, resting, traveling, and 

socializing, on a diel cycle (24-hour 

cycle). Disruption of functions resulting 

from reactions to stressors such as 

sound exposure are more likely to be 

significant if they last more than one 

diel cycle or recur on subsequent days 

(Southall et al., 2007). Consequently, a 

behavioral response lasting less than 

one day and not recurring on 

subsequent days is not considered 

particularly severe unless it could 

directly affect reproduction or survival 

(Southall et al., 2007). Note that there is 

a difference between multi-day 

substantive behavioral reactions and 

multi-day anthropogenic activities. For 

example, just because an activity lasts 

for multiple days does not necessarily 

mean that individual animals are either 

exposed to activity-related stressors for 

multiple days or, further, exposed in a 

manner resulting in sustained multi-day 

substantive behavioral responses. 

Stress responses—An animal’s 

perception of a threat may be sufficient 

to trigger stress responses consisting of 

some combination of behavioral 

responses, autonomic nervous system 

responses, neuroendocrine responses, or 

immune responses (e.g., Seyle, 1950; 

Moberg, 2000). In many cases, an 

animal’s first and sometimes most 

economical (in terms of energetic costs) 

response is behavioral avoidance of the 

potential stressor. Autonomic nervous 

system responses to stress typically 

involve changes in heart rate, blood 

pressure, and gastrointestinal activity. 

These responses have a relatively short 

duration and may or may not have a 

significant long-term effect on an 

animal’s fitness. 

Neuroendocrine stress responses often 

involve the hypothalamus-pituitaryadrenal system. Virtually all 

neuroendocrine functions that are 


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affected by stress—including immune 

competence, reproduction, metabolism, 

and behavior—are regulated by pituitary 

hormones. Stress-induced changes in 

the secretion of pituitary hormones have 

been implicated in failed reproduction, 

altered metabolism, reduced immune 

competence, and behavioral disturbance 

(e.g., Moberg, 1987; Blecha, 2000). 

Increases in the circulation of 

glucocorticoids are also equated with 

stress (Romano et al., 2004). 

The primary distinction between 

stress (which is adaptive and does not 

normally place an animal at risk) and 

‘‘distress’’ is the cost of the response. 

During a stress response, an animal uses 

glycogen stores that can be quickly 

replenished once the stress is alleviated. 

In such circumstances, the cost of the 

stress response would not pose serious 

fitness consequences. However, when 

an animal does not have sufficient 

energy reserves to satisfy the energetic 

costs of a stress response, energy 

resources must be diverted from other 

functions. This state of distress will last 

until the animal replenishes its 

energetic reserves sufficient to restore 

normal function. 

Relationships between these 

physiological mechanisms, animal 

behavior, and the costs of stress 

responses are well-studied through 

controlled experiments and for both 

laboratory and free-ranging animals 

(e.g., Holberton et al., 1996; Hood et al., 

1998; Jessop et al., 2003; Krausman et 

al., 2004; Lankford et al., 2005). Stress 

responses due to exposure to 

anthropogenic sounds or other stressors 

and their effects on marine mammals 

have also been reviewed (Fair and 

Becker, 2000; Romano et al., 2002b, 

Wright et al., 2007) and, more rarely, 

studied in wild populations (e.g., 

Romano et al., 2002a). For example, 

Rolland et al. (2012) found that noise 

reduction from reduced ship traffic in 

the Bay of Fundy was associated with 

decreased stress in North Atlantic right 

whales. These and other studies lead to 

a reasonable expectation that some 

marine mammals will experience 

physiological stress responses upon 

exposure to acoustic stressors and that 

it is possible that some of these would 

be classified as ‘‘distress.’’ In addition, 

any animal experiencing TTS would 

likely also experience stress responses 

(NRC, 2003). 

Masking—Sound can disrupt behavior 

through masking, or interfering with, an 

animal’s ability to detect, recognize, or 

discriminate between acoustic signals of 

interest (e.g., those used for intraspecific 

communication and social interactions, 

prey detection, predator avoidance, 

navigation) (Richardson et al., 1995). 

Masking occurs when the receipt of a 

sound is interfered with by another 

coincident sound at similar frequencies 

and at similar or higher intensity, and 

may occur whether the sound is natural 

(e.g., snapping shrimp, wind, waves, 

precipitation) or anthropogenic (e.g., 

pile driving, shipping, sonar, seismic 

exploration) in origin. The ability of a 

noise source to mask biologically 

important sounds depends on the 

characteristics of both the noise source 

and the signal of interest (e.g., signal-tonoise ratio, temporal variability, 

direction), in relation to each other and 

to an animal’s hearing abilities (e.g., 

sensitivity, frequency range, critical 

ratios, frequency discrimination, 

directional discrimination, age or TTS 

hearing loss), and existing ambient 

noise and propagation conditions. 

Masking of natural sounds can result 

when human activities produce high 

levels of background sound at 

frequencies important to marine 

mammals. Conversely, if the 

background level of underwater sound 

is high (e.g., on a day with strong wind 

and high waves), an anthropogenic 

sound source would not be detectable as 

far away as would be possible under 

quieter conditions and would itself be 

masked. Given the limited vessel traffic 

near the Project Area and intermittent 

nature of pile installation and removal 

operations, any masking effects on 

marine mammals would likely be 

negligible. 

In-Water Construction Effects on 

Marine Mammal Habitat—NSF’s 

construction activities could have 

localized, temporary impacts on marine 

mammal habitat by increasing in-water 

sound pressure levels and slightly 

decreasing water quality. Construction 

activities are of short duration and 

would likely have temporary impacts on 

marine mammal habitat through 

increases in underwater sound. 

Increased noise levels may affect 

acoustic habitat (see masking discussion 

above) and adversely affect marine 

mammal prey in the vicinity of the 

project area (see discussion below). 

During pile installation activities, 

elevated levels of underwater noise 

would ensonify Hero Inlet and nearby 

waters where both fish and mammals 

may occur and could affect foraging 

success. Additionally, marine mammals 

may avoid the area during construction, 

however, displacement due to noise is 

expected to be temporary and is not 

expected to result in long-term effects to 

the individuals or populations. 

Pile driving activities may 

temporarily increase turbidity resulting 

from suspended sediments. Any 

increases would be temporary, 

localized, and minimal. In general, 

turbidity associated with pile 

installation is localized to about a 25- 

foot (7.6 m) radius around the pile 

(Everitt et al., 1980). Cetaceans are not 

expected to be close enough to the 

project activity areas to experience 

effects of turbidity, and any small 

cetaceans and pinnipeds could avoid 

localized areas of turbidity. Therefore, 

the impact from increased turbidity 

levels is expected to be discountable to 

marine mammals. No turbidity impacts 

to Hero Inlet or nearby foraging habitats 

are anticipated. 

Sound may affect marine mammals 

and their habitat through impacts on the 

abundance, behavior, or distribution of 

prey species (e.g., crustaceans, 

cephalopods, fish, and zooplankton). 

Marine mammal prey varies by species, 

season, and location. Here, we describe 

studies regarding the effects of noise on 

known marine mammal prey. 

Fish utilize the soundscape and 

components of sound in their 

environment to perform important 

functions such as foraging, predator 

avoidance, mating, and spawning (e.g., 

Zelick and Mann, 1999; Fay, 2009). 

Depending on their hearing anatomy 

and peripheral sensory structures, 

which vary among species, fishes hear 

sounds using pressure and particle 

motion sensitivity capabilities and 

detect the motion of surrounding water 

(Fay et al., 2008). The potential effects 

of noise on fishes depends on the 

overlapping frequency range, distance 

from the sound source, water depth of 

exposure, and species-specific hearing 

sensitivity, anatomy, and physiology. 

Key impacts to fishes may include 

behavioral responses, hearing damage, 

barotrauma (pressure-related injuries), 

and mortality. 

Fish react to sounds that are 

especially strong and/or intermittent 

low-frequency sounds, and behavioral 

responses such as flight or avoidance 

are the most likely effects. Short 

duration, sharp sounds can cause overt 

or subtle changes in fish behavior and 

local distribution. The reaction of fish to 

noise depends on the physiological state 

of the fish, past exposures, motivation 

(e.g., feeding, spawning, migration), and 

other environmental factors. Hastings 

and Popper (2005) identified several 

studies that suggest fish may relocate to 

avoid certain areas of sound energy. 

Additional studies have documented 

effects of pile driving on fish, although 

several are based on studies in support 

of large, multiyear bridge construction 

projects (e.g., Scholik and Yan, 2001, 

2002; Popper and Hastings, 2009). 

Several studies have demonstrated that 

impulse sounds might affect the 


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distribution and behavior of some 

fishes, potentially impacting foraging 

opportunities or increasing energetic 

costs (e.g., Fewtrell and McCauley, 

2012; Pearson et al., 1992; Skalski et al., 

1992; Santulli et al., 1999; Paxton et al., 

2017). However, some studies have 

shown no or slight reaction to impulse 

sounds (e.g., Pena et al., 2013; Wardle 

et al., 2001; Jorgenson and Gyselman, 

2009; Cott et al., 2012). 

Sound pressure levels (SPLs) of 

sufficient strength have been known to 

cause injury to fish and fish mortality. 

However, in most fish species, hair cells 

in the ear continuously regenerate and 

loss of auditory function likely is 

restored when damaged cells are 

replaced with new cells. Halvorsen et 

al., (2012a) showed that a TTS of 4–6 dB 

was recoverable within 24 hours for one 

species. Impacts would be most severe 

when the individual fish is close to the 

source and when the duration of 

exposure is long. Injury caused by 

barotrauma can range from slight to 

severe and can cause death, and is most 

likely for fish with swim bladders. 

Barotrauma injuries have been 

documented during controlled exposure 

to impact pile driving (Halvorsen et al., 

2012b; Casper et al., 2013). 

The most likely impact to fish from 

construction activities at the Project 

Area would be temporary behavioral 

avoidance of the area. The duration of 

fish avoidance of this area after pile 

driving stops is unknown, but a rapid 

return to normal recruitment, 

distribution and behavior is anticipated. 

Airborne Acoustic Effects—Pinnipeds 

that occur near the project site could be 

exposed to airborne sounds associated 

with pile driving that have the potential 

to cause behavioral harassment, 

depending on their distance from pile 

driving activities. However, in-air noise 

generated during pile driving activities 

at the pier should attenuate in air to less 

than levels that exceed NMFS 

established Level B harassment 

thresholds, before reaching the opposite 

side of Hero Inlet where seals may be on 

shore. A 2016 Final Rule for 

construction of a Navy Pier (81 FR 

52614; August 9, 2016) estimated the 

greatest possible distances to airborne 

noise during installation of a 24′′ steel 

pile (using a source level of 111 dB re 

20 microPascals) as 168.3 m to the 90 

dB threshold for harbor seals and 53.2 

m for all other seals (using a 100dB 

threshold). A 2019 Final Rule published 

for construction of the Liberty 

Development in Alaska estimated 

airborne noise during impact pile 

driving as 81 dB re 20 microPascals at 

100 m and 93 dB re 20 microPascals at 

160 m (84 FR 70274; December 20, 

2019). Therefore, based on the distance 

to Bonaparte Point, it is unlikely that 

animals hauled out across Hero Inlet 

will be exposed to levels above the 

NMFS Level B harassment threshold for 

disturbance. 

In summary, given the relatively small 

areas being affected (i.e., Hero Inlet and 

highly truncated sound fields extending 

out to 18 km), construction activities 

associated with the proposed action are 

not likely to have a permanent, adverse 

effect on any fish habitat, or populations 

of fish species. Any behavioral 

avoidance by fish of the disturbed area 

would still leave significantly large 

areas of fish and marine mammal 

foraging habitat in the nearby vicinity. 

Thus, we conclude that impacts of the 

specified activity are not likely to have 

more than short-term adverse effects on 

any prey habitat or populations of prey 

species. Further, any impacts to marine 

mammal habitat are not expected to 

result in significant or long-term 

consequences for individual marine 

mammals, or to contribute to adverse 

impacts on their populations. 

Estimated Take 

This section provides an estimate of 

the number of incidental takes proposed 

for authorization through this IHA, 

which will inform both NMFS’ 

consideration of ‘‘small numbers’’ and 

the negligible impact determination. 

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 would primarily be 

by Level B harassment, as use of the 

acoustic sources (i.e., pile installation 

and removal 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 

mysticetes due to large PTS zones as 

well as for phocids and otariids due to 

haulouts in the vicinity of the Project 

Area. Auditory injury is unlikely to 

occur for high frequency or midfrequency species. The proposed 

mitigation and monitoring measures are 

expected to minimize the severity of the 

taking to the extent practicable. 

As described previously, no mortality 

or serious injury is anticipated or 

proposed to be authorized for this 

activity. Below we describe how the 

take is estimated. 

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) and the number of days of 

activities. We note that while these 

factors can contribute to a basic 

calculation to provide an initial 

prediction of 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 proposed 

take estimate. 

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 PTS of some 

degree (equated to Level A harassment). 

Level B Harassment for non-explosive 

sources—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 (e.g., frequency, predictability, 

duty cycle), the environment (e.g., 

bathymetry), and the receiving animals 

(hearing, motivation, experience, 

demography, behavioral context) and 

can be difficult to predict (Southall et 

al., 2007, Ellison et al., 2012). Based on 

what the available science indicates and 

the practical need to use a threshold 

based on a factor that is both predictable 

and measurable for most activities, 

NMFS uses a generalized acoustic 

threshold based on received level to 

estimate the onset of behavioral 

harassment. NMFS predicts that marine 

mammals are likely to be behaviorally 

harassed in a manner we consider Level 

B harassment when exposed to 

underwater anthropogenic noise above 

received levels of 120 dB re 1 mPa (rms) 

for continuous (e.g., vibratory piledriving, DTH) and above 160 dB re 1 

mPa (rms) for non-explosive impulsive 


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(e.g., seismic airguns, impact pile 

driving) or intermittent (e.g., scientific 

sonar) sources. 

DTH pile installation includes drilling 

(non-impulsive sound) and hammering 

(impulsive sound) to penetrate rocky 

substrates (Denes et al., 2016; Denes et 

al., 2019; Reyff and Heyvaert 2019). 

DTH pile installation was initially 

thought be a primarily non-impulsive 

noise source. However, Denes et al., 

(2019) concluded from a study 

conducted in Virginia, that DTH pile 

installation should also be characterized 

as impulsive based on Southall et al., 

(2007), who stated that signals with a >3 

dB difference in sound pressure level in 

a 0.035-second window compared to a 

1-second window can be considered 

impulsive. Therefore, DTH pile 

installation is treated as both an 

impulsive and non-impulsive noise 

source. In order to evaluate Level A 

harassment, DTH pile installation 

activities are evaluated according to the 

impulsive criteria and using 160 dB 

rms. Level B harassment isopleths for 

DTH are determined by applying nonimpulsive criteria and using the 120 dB 

rms threshold which is also used for 

vibratory driving. This approach 

ensures that the largest ranges to effect 

for both Level A and Level B harassment 

are accounted for in the take estimation 

process for DTH. 

NSF’s proposed activity includes the 

use of continuous (vibratory hammer, 

DTH pile installation, hydrogrinder) and 

impulsive (impact pile driving, DTH 

pile installation) sources, and therefore 

the 120 and 160 dB re 1 mPa (rms) is/ 

are applicable. 

Level A harassment for non-explosive 

sources—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). NSF’s proposed activity 

includes the use of impulsive (i.e., 

impact hammer, DTH pile installation) 

and non-impulsive (i.e., vibratory 

hammer, DTH pile installation, rock 

chipping, hydrogrinder) sources. 

These thresholds are provided in the 

Table 6. 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/marinemammal-acoustic-technical-guidance. 

TABLE 6—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. 

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 will feed into identifying the area 

ensonified above the acoustic 

thresholds, which include source levels 

and transmission loss coefficient. 

The sound field in the Project Area is 

the existing background noise plus 

additional construction noise from the 

proposed project. Marine mammals are 

expected to be affected via sound 

generated by the primary components of 

the project (i.e., DTH pile installation, 

vibratory pile removal, limited impact 

for proofing purpose, rock chipping and 

use of hydrogrinders). 

The estimated sound source levels 

(SSL) proposed by NSF and used in this 

assessment are described below and are 

shown in Table 7. Appendix A in the 

application discusses in detail the 

sound source levels for all planned 

equipment. Sound levels from pile 

installation used in NSF’s application 

came from the Caltrans Compendium 

(2015) or are based on empirical data 

collected from other sites with similar 

conditions (e.g., rock substrate where 

DTH driving would be used to install 

piles). NSF referenced two studies to 

arrive at SSLs for 24-in DTH pile 

installation. Noise studies from Kodiak 

ferry terminal (Denes et al., 2016) and 

Skagway cruise ship terminal (Reyff and 

Heyvart, 2019; Reyff, 2020). Results are 

shown in Table 7. NMFS has developed 

DTH pile installation guidelines which 

contain recommendations for 

appropriate SSLs. NSF applied these 

recommendations for 36-in DTH pile 

installation. However, NSF proposed to 

use the DTH pile installation SSLs 

shown in Table 7, which for 24-in DTH 

pile installation and 24-in sockets 

which are more conservative than those 

recommended by NMFS, and NMFS 

deemed this approach acceptable. 

NSF determined the SSLs for rock 

chipping based on underwater sounds 

measured for concrete demolition. NSF 

examined two sets of data available 

during the demolition of the Tappan 

Zee Bridge (state of New York) pier 

structures. NSF also considered the 

results from another study conducted by 

the Washington State Department of 

Transportation (WSDOT). Results from 

that analysis are shown in Table 7. 

The U.S. Navy has assessed sound 

levels of the use of a hydrogrinder 

through underwater measurements (U.S. 

Navy 2018). The Navy measurements 

were reported in 1/1-octave frequency 

bands from 125 to 8,000 Hz for the 

helmet position that was assumed to be 


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0.5 to 1 meter from the hydraulic 

grinder operation. The overall 

unweighted sound level was computed 

to be 167.5 dB at 0.5 to 1 meter. Source 

sound levels in this report are provided 

for 10-m distances. Since this is a point 

source of sound, spherical spreading 20 

Log TL coefficient results in a source 

sound level of 142 to 148 dB at 10 

meters (see Appendix A in the 

application). A value of 146 dB at 10m 

has been used to estimate marine 

mammal take associated with these 

tools. 

NSF assumed that installation of 

approximately one to two piles would 

occur over a 12-hour work day. To be 

precautionary in calculating isopleths, 

this application assumes two 

installation activities would occur 

simultaneously. For example, two 36-in 

piles installed simultaneously or one 

36-in pile and one 24-in pile. Brief 

impact pile driving of about 10 strikes 

may be used to seat the piles. A likely 

approach to installing 36-in piles would 

be to use DTH to install two 36-in piles 

simultaneously; one 36-in pile would be 

installed to 20-ft socket depth while a 

second 36-in abutment pile would be 

installed to a 30-ft socket depth. The 

abutment piles require additional depth 

to support lateral loads and to provide 

side friction against ice uplift that could 

occur at the shoreline. It is also possible 

that both 36-in piles may be installed 

simultaneously to 20-ft socket. 

Rock chipping may be required to 

level pile areas and would normally 

occur on the same day as DTH pile 

installation, if possible. If rock chipping 

is conducted separately from DTH pile 

installation, takes are accounted for by 

using the area ensonified during DTH 

pile installation to calculate takes. This 

precautionary approach overestimates 

takes that could occur if only rock 

chipping is conducted by itself. Rock 

chipping is considered to be an 

impulsive source. 

Existing sheetpile would be removed 

through vibratory extraction. In some 

instances it may be necessary to remove 

piles by cutting them off at the mudline 

using underwater hand cutting tools. 

Such activity would occur on the same 

days as vibratory extraction. Cutting 

piles off at the mudline would result in 

less underwater noise than vibratory 

removal. To be precautionary, estimated 

marine mammal takes were calculated 

by assuming all piles were removed by 

vibratory extraction. 

TABLE 7—SOUND SOURCE LEVELS

Measured sound levels 1

Source 

Activity Peak RMS SEL 2 TL 

24-in Piles 

DTH pile installation ...... 190 166 154 15 Denes et al., (2016). 

Vibratory Driving 4 .......... 170 165 165 15 Caltrans (2015). 

Impact Driving ................ 195 181 168 15 Caltrans (2015). 

36-in Piles 

DTH pile installation ...... 194 166 164 15 The DTH sound source proxy of 164 dB SEL is 

from 42-in piles, Reyff (2020) and Denes et 

al., (2019). 

Vibratory Driving ............ 180 170 170 15 Caltrans (2015). 

Impact Driving ................ 210 193 183 15 Caltrans (2015). 

H Piles inserted in 24-in. Sockets 

DTH pile installation ...... 190 166 154 15 Denes et al., (2016). 

Vibratory Driving ............ 170 165 165 15 Caltrans (2015). 

Impact Driving ................ 195 180 170 15 Caltrans (2015). 

Removal of 24-in Template Piles 

Vibratory Driving ............ 170 165 165 15 Caltrans (2015). 

Removal of Sheet Piles 

Vibratory Driving ............ 175 160 160 15 Caltrans (2015). 

Rock Chipping 

Hydraulic Breaker .......... 197 184 175 22 Tappan Zee Bridge 6 7. 

Anode Installation 

Hydro-grinder ................. ........................ 146 ........................ 20 U.S. Navy (2008). 

1See Appendix A in application for references and discussion of all sound sources. 

2SEL is single strike for impact driving and DTH pile installation. SEL for vibratory installation is per second. 

4 Includes removal of 24-in. piles 

5While it is possible the socket depth would be only 20 feet, this application assumes the greater depth to be precautionary. 

6 Reyff, J. 2018. Demolition of Existing Tappan Zee Bridge. Summary of Underwater Sound Measurements for Mechanical Demolition of Concrete Pile Caps at Piers 114 and 115, Circular Caisson at Pier 166, and Rectangular Caisson at Pier 170. To David Capobianco, New York State 

Thruway Authority. December 18, 2020. 7 Reyff, J. 2018. Demolition of Existing Tappan Zee Bridge Subject: Summary of Underwater Sound Measurements for Mechanical Demolition 

of Ice Breakers at Piers 173 and 169. To Kristine Edwards, New York State Thruway Authority. January 10, 2018. 


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When the sound fields from two or 

more concurrent pile installation 

activities overlap, the decibel addition 

of continuous noise sources results in 

much larger zone sizes than a single 

source. Decibel addition is not a 

consideration when sound fields do not 

overlap. The increased SLs potentially 

associated with two concurrent sources 

with overlapping sound fields are 

shown in Table 8 (WSDOT 2015). 

Decibel addition is only applicable to 

continuous sources. According to NMFS 

guidance the SL for continuous sounds 

from DTH pile installation is 166 dB 

regardless of the size of the pile. Under 

decibel addition, simultaneous DTH 

pile installation activities would use a 

SL of 169 (166 + 3) to derive the 

isopleth for the Level B harassment 

zone. 

TABLE 8—SIMULTANEOUS SOURCE DECIBEL ADDITION

Hammer types Difference 

in SSL Level A zones Level B zones 

Vibratory, Impact .............. Any ............ Use impact zones .................................................. Use largest zone. 

Impact, Impact ................. Any ............ Use zones for each pile size and number of 

strikes.

Use zone for each pile size. 

Vibratory, Vibratory .......... 0 or 1 dB ... Add 3 dB to the higher source level ..................... Add 3 dB to the higher source level. 

2 or 3 dB ... Add 2 dB to the higher source level ..................... Add 2 dB to the higher source level. 

4 to 9 dB .... Add 1 dB to the higher source level ..................... Add 1 dB to the higher source level. 

10 dB or 

more.

Add 0 dB to the higher source level ..................... Add 0 dB to the higher source level. 

Level B Harassment Zones 

Transmission loss (TL) is the decrease 

in acoustic intensity as an acoustic 

pressure wave propagates out from a 

source. TL parameters vary with 

frequency, temperature, sea conditions, 

current, source and receiver depth, 

water depth, water chemistry, and 

bottom composition and topography. 

The general formula for underwater TL 

is: 

TL = B * Log10 (R1/R2), 

Where: 

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 NSF’s 

proposed activity in the absence of 

specific modelling. Level B harassment 

isopleths are shown in Table 15 and 

Table 16. 

Level A Harassment Zones 

When the NMFS Technical Guidance 

(2016) was published, in recognition of 

the fact that ensonified area/volume 

could be more technically challenging 

to predict because of the duration 

component in the new thresholds, we 

developed a User Spreadsheet that 

includes tools to help predict a simple 

isopleth that can be used in conjunction 

with marine mammal density or 

occurrence to help predict takes. We 

note that because of some of the 

assumptions included in the methods 

used for these tools, we anticipate that 

isopleths produced are typically going 

to be overestimates of some degree, 

which may result in some degree of 

overestimate of Level A harassment 

take. However, these tools offer the best 

way to predict appropriate isopleths 

when more sophisticated 3D modeling 

methods are not available, and NMFS 

continues to develop ways to 

quantitatively refine these tools, and 

will qualitatively address the output 

where appropriate. For stationary 

sources such as those planned for this 

project, NMFS User Spreadsheet 

predicts the distance at which, if a 

marine mammal remained at that 

distance the whole duration of the 

activity, it would incur PTS. Inputs 

used in the User Spreadsheet, and the 

resulting isopleths are reported below. 

Tables 9, 10 and 11 shows User inputs 

for single sound sources while Tables 

12, 13, and 14 contain User inputs for 

simultaneous sources. The resulting 

Level A harassment isopleths for nonsimultaneous activities and 

simultaneous activities are shown in 

Table 15 and Table 16 respectively. 

Level B harassment isopleths for 

simultaneous DTH pile installation 

utilize a 169 dB SL and corresponding 

isopleths are shown in Table 16. Note 

that strike numbers for DTH pile 

installation were derived by applying 

the duration required to drive a single 

pile (minutes), the number of piles 

driven per day, and the strike rate 

(average strikes per second) rates to 

arrive at the total number of strikes in 

a 24-hour period. A rate of 10 strikes per 

second was assumed. 

TABLE 9—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUTS TO CALCULATE PTS ISOPLETHS FOR NONSIMULTANEOUS VIBRATORY PILE INSTALLATION ACTIVITIES AND HYDROGRINDING

36-in (dock 

dock 

abutment)-in 

RHIB fender 

piles 24-in 

24-in template 

10′ socket 

24-in wave 

attenuator 

piles-in 

24-in template 

pile removal 

Sheet pile 

removal 

Anode 

installation 

(hydrogrinding) 

Spreadsheet tab used A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

Source Level (SPL RMS) .............................. 170 165 165 165 165 160 146 

15 Transmission Loss Coefficient ................. 15 15 15 15 15 15 20 

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

Time to install/remove single pile (minutes) 30 30 30 30 30 30 120 

Piles to install/remove per day ...................... 1 1 2 1 16 16 1 


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TABLE 10—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUT TO CALCULATE PTS ISOPLETHS FOR NONSIMULTANEOUS IMPACT PILE INSTALLATION ACTIVITIES

36-in 

(dock, dock 

abutment) 

24-in RHIB 

(template, 

wave 

attenuator) 

Rock chipping 

Spreadsheet Tab Used E.1) Impact 

pile driving E.1) Impact 

pile driving 

E) Stationary 

source: 

impulsive, 

intermittent 

Source Level (Single Strike/shot SEL) ........................................................................................ 183 168 197 

Transmission Loss Coefficient ..................................................................................................... 15 15 22 

Weighting Factor Adjustment (kHz) ............................................................................................. 2 2 0 

Number of pulses in 1-hr period .................................................................................................. 10 10 2,700 

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

TABLE 11—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUT TO CALCULATE PTS ISOPLETHS FOR NONSIMULTANEOUS DTH PILE INSTALLATION ACTIVITIES

36-in dock 20′ 

socket 

Dock abutment-36-in 

30′ socket 

24-in RHIB, 

template, 

wave 

attenuator 

Spreadsheet tab used E.2) DTH pile 

driving E.2) DTH pile 

driving E.2) DTH pile 

driving 

Source Level (Single Strike/Shot SEL) ....................................................................................... 164 164 154 

Transmission Loss Coefficient ..................................................................................................... 15 15 15 

Strike rate (Strikes/sec) ............................................................................................................... 10 10 10 

Duration (min) .............................................................................................................................. 345 518 345 

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

SStrikes/pile ................................................................................................................................. 207,000 310,500 207,000 

Piles to install/remove per day .................................................................................................... 1 1 1 

TABLE 12—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUT TO CALCULATE PTS ISOPLETHS FOR

SIMULTANEOUS VIBRATORY PILE INSTALLATION ACTIVITIES

36-in dock 20′ 

socket x 2 

dock abutment 

RHIB fender 

piles 24-in x 2 

24-in template 

10′ socket x 4 

24-in wave 

attenuator 

piles-10′ 

socket x 2 

24-in wave 

attenuator 

piles-20′ 

socket x 2 

Spreadsheet tab used A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

A.1) Nonimpul, stat, 

cont. 

Source Level (SPL RMS) .................................................... 173 168 168 168 168 

Transmission Loss Coefficient ............................................. 15 15 15 15 15 

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

Time to install/remove single pile (minutes) ........................ 30 30 15 30 30 

Piles to install/remove per day ............................................ 2 2 4 2 2 

TABLE 13—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUT TO CALCULATE PTS ISOPLETHS FOR

SIMULTANEOUS IMPACT PILE INSTALLATION ACTIVITIES

36-in (dock 20′ 

socket x 2) 

or 

dock abutment-36-in 

30′ and 20′ 

socket 

RHIB fender 

piles 24-in x 2 

24-in template 

10′ socket x 4 

24-in wave 

attenuator 

piles x 2 

Spreadsheet tab used 

E.1) Impact 

pile driving 

E.1) Impact 

pile driving 

E.1) Impact 

pile driving E.1) Impact 

pile driving 

Source Level (Single Strike/shot SEL) ............................................................ 183 168 168 168 

Transmission Loss Coefficient ......................................................................... 15 15 15 15 

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

Strikes/pile ....................................................................................................... 10 10 10 10 

Piles per day .................................................................................................... 2 2 4 2 


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TABLE 14—NMFS TECHNICAL GUIDANCE (2020) USER SPREADSHEET INPUT TO CALCULATE PTS ISOPLETHS FOR

SIMULTANEOUS DTH PILE INSTALLATION ACTIVITIES

36-in dock 20′ 

socket x 2 

Dock 

abutment36-in 

30′ and 20′ 

socket 

24-in template 

10′ socket x 4 

24-in wave 

attenuator 

piles10′ socket x 2/ 

RHIB fender 

Spreadsheet tab used E.2) DTH pile piles 24-in x 2 

driving E.2) DTH pile 

driving 

E.2) DTH pile 

driving 

E.2) DTH pile 

driving 

Source Level (Single Strike/Shot SEL) ............................................................ 164 164 154 154 

Transmission Loss Coefficient ......................................................................... 15 15 15 15 

Strike rate (Strikes/sec) ................................................................................... 10 10 10 10 

Duration (min) .................................................................................................. 345 430 172.5 345 

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

Strikes/pile ....................................................................................................... 414,000 517,500 103,500 207,000 

Piles to install per day ..................................................................................... 2 2 4 2 

TABLE 15—LEVEL A AND LEVEL B HARASSMENT ISOPLETHS FOR NON-SIMULTANEOUS PILE INSTALLATION ACTIVITIES

Level A harassment zones (m) 

based on SELcum Level B 

harassment zone 

(m) 

Cetaceans Pinnipeds 

LF MF HF PW OW 

Dock, 36-in Dia. Pile Installation, 20′ Socket Depth— 

1 pile/day.

DTH Pile Drilling ............... 1,891 67 2,253 1,012 74 11,659 

Dock Abutment, 36-in Dia. Pile Installation, 30′ Socket Depth—1 pile/day.DTH Pile Drilling ............... 2,478 88 2,951 1,326 97 11,659 

RHIB Fender Piles, 24-in Dia. Pile Installation, 20′ 

Socket—1 pile/day.

DTH Pile Drilling ............... 407 15 485 218 16 11,659 

24-in Dia. Template Piles, 10′ Socket Depth—2 piles/ 

day.

DTH Pile Drilling ............... 407 15 485 218 16 11,659 

24-in Dia Wave Attenuator Piles, 20′ Socket Depth— 

1 pile/day.

DTH Pile Drilling ............... 407 15 485 218 16 11,659 

Retaining Wall HP Pile inserted in Drilled 24-in Dia 

Sockets, 20′ Socket Depth—1 pile/day.

DTH Pile Drilling ............... 407 15 485 218 16 11,659 

Removal of 24-in Dia. Template Piles—16 piles ......... Vibratory ........................... 51 5 75 31 2 10,000 

Removal of Sheet Piles ............................................... Vibratory ........................... 23 2 35 14 1 4,642 

Rock Chipping/Floor Preparation ................................. Hydraulic Breaker ............. 403 50 716 204 29 123 

Anode Installation ........................................................ Hydrogrinder ..................... 1.9 0.3 2.5 1.3 0.2 200 

TABLE 16—LEVEL A AND LEVEL B HARASSMENT ISOPLETHS FOR SIMULTANEOUS PILE INSTALLATION ACTIVITIES

Daily activity scenario Installation 

method 

Level A harassment zones (m) 

based on SELcum Level B 

harassment 

zone 

(m) 

Cetaceans Pinnipeds 

LF MF HF PW OW 

Dock, 36-in Dia. Pile Installation, 20′ Socket Depth— 

2 pile/day.

DTH Pile Installation ......... 3,002 107 3,576 1,607 117 18,478 

Dock Abutment, 36-in Dia. Pile Installation, 30′ Socket Depth and 36-in Dia. Pile 20′ Socket Depth.3,484 124 4,149 1,864 136 18,478 

RHIB Fender Piles, 24-in Dia. Pile Installation, 20′ 

Socket—2 pile/day.

647 23 770 346 25 18,478 

24-in Dia. Template Piles, 10′ Socket Depth—4 piles/ 

day.

24-in Dia Wave Attenuator Piles, 20′ Socket Depth— 

2 pile/day.

Retaining Wall—HP Pile inserted in Drilled 24-in Dia 

Sockets, 20′ Socket Depth—2 piles/day.

Dock, 36-in Dia. Pile Installation, 20′ Socket Depth— 

1 pile/day and Wave Attenuator, 24-in Dia. Pile Installation, 20′ Socket—1 pile/day.

2,011 72 2,395 1,076 78 18,478 

Dock 36-in Dia. Pile Installation 30′ Socket Depth and 

24-in Dia Pile Installation 20′ Socket Depth.

2,885 103 3,436 1,544 133 18,478 

36-in Dock 20′ socket x 2 Dock Abutment .................. Vibratory Installation ......... 43 4 64 26 2 34,146 

RHIB Fender Piles 24-in x 2 ........................................ 20 2 30 12 1 15,849 

24-in template 10′ socket x 4.

24-in wave attenuator piles-10′ socket x 2 .................. 31.8 3 47 19 1.4 

24-in wave attenuator piles-20′ socket x 2.


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The calculated area that would be 

ensonified by single or multiple pile 

installation and removal sound sources 

is calculated based on the distance from 

the Palmer Station Pier installation 

location to the edge of the isopleth for 

Level B harassment and for each hearing 

group for Level A harassment. The 

scenario with the largest zone is used to 

estimate potential marine mammal 

exposures and those areas are shown in 

Table 17. The Palmer Station Pier is 

located in a narrow portion of Hero Inlet 

and the areas potentially ensonified 

above Level A and Level B harassment 

thresholds is truncated by the location 

of land masses including assorted 

islands (i.e., shadow effect). 

Table 16 shows the construction 

scenario (installation of two 36-in piles, 

one at 30- ft and a second at 20-ft socket 

depth) that results in the largest PTS 

zone isopleths while Table 17 shows the 

areas of the corresponding zones 

ensonified areas. The maximum Level A 

harassment distance would be 1,864 m 

(1.4 km2) for phocids in water (PW), 

3,484m (3.38 km2) for LF cetaceans, and 

4,149m (4.4 km2) for HF cetaceans 

(although HF cetaceans are considered 

rare in the Project Area and Level A 

harassment takes are not proposed). The 

largest Level B harassment isopleth is 

associated with simultaneous DTH pile 

installation and would be at a distance 

of 18,478 m from the source covering an 

area of 54.99 m. 

TABLE 17—HARASSMENT ZONE AREAS USED FOR TAKE ESTIMATION 1

Pile type Total piles 

Level A max area 

cetaceans3

(km2) 

Level A max area 

pinnipeds3

(km2) 

Level B area 

all species 

(km2) 

36-in piles (one @30-ft socket depth and one @20-ft socket depth) 18 

4 

3.38 (LF), 4.4 

(HF), 0.03 (MF) 

1.4 (PW), 0.03 

(OW) 

54.99 

32-in piles (Bent 1).

Pile Removal (24-in) ............................................................................ 16 0.006 (LF), 0.012 

(MF), ∼0 (MF) 

0.002 (PW) 20.78 

Sheetpile Removal ............................................................................... 20 0.001 (LF), 0.003 

(HF), ∼0 (MF) 

0.0006 (PW) 5.27 

Anode Installation ................................................................................ n/a n/a n/a 0.07 

Rock Chipping ..................................................................................... unk 

Total .............................................................................................. 88 

1Assumes simultaneous installation (i.e., two pile installations occurring at the same time). 

Marine Mammal Occurrence and Take 

Estimation 

In this section we provide the 

information about the presence, density, 

or group dynamics of marine mammals 

that will inform the take calculations. 

The approach by which the 

information provided above is brought 

together to produce a quantitative take 

estimate is described here. For some 

species only observational data is 

available and is used to estimate take. 

For marine mammals with known 

density information estimated 

harassment take numbers are calculated 

using the following equation (summed 

across each type of activity): 

Estimated take = animal density × 

ensonified area × operating days 

As noted above we used the most 

conservative option for estimating 

ensonified area for each activity. We 

also used conservative estimates of the 

number of days of work for each 

activity. 

Takes were estimated by considering 

the density of marine mammals per km2

multiplied by the potential area 

ensonified (km2) and the number of 

days the noise could occur during inwater construction. The Project Area is 

located in the nearshore environment 

relative to the Antarctic Peninsula as 

defined by data reported in Santora et 

al. (2009). Sources for density data and 

average group sizes are found in Table 

6–3 in the application. For some species 

only offshore data were available, for 

some only nearshore data, and for others 

data existed for both areas. Offshore 

densities were used to estimate take for 

eight species. Nearshore densities were 

unavailable for three species. Nearshore 

densities were used to calculate take for 

four species. Data from these offshore 

sources results in averaging across large 

portions of the region. NSF notes that 

these data are from areas where 

cetaceans may occur in significantly 

greater densities than the Palmer Pier 

Project Area due to expected increased 

faunal density along the sea ice edge 

and shelf-frontal features in the 

southern oceans. These oceanographic 

features are not present within the 

Project Area, so lower densities of 

cetaceans are expected within close 

proximity to Palmer Station. Therefore, 

the offshore densities may represent an 

overestimate of anticipated densities 

within the Palmer Station Project Area. 

NSF estimated Level A harassment 

takes by multiplying the Level A 

harassment areas by the species density 

(nearshore or offshore as described 

above) which was then multiplied by 

the expected number of pile driving 

days for each activity type. The 

exposures for each activity were added 

to arrive at calculated Level A 

harassment take number as shown in 

Table 20. In cases where both nearshore 

and offshore densities were available, 

the higher of the two densities is used 

to estimate take. Note that designated 

shutdown zones cover all of the Level 

A harassment zones with the exception 

of pinnipeds, where the zones in some 

cases are larger than the proposed 50-m 

shutdown zone. However, we are 

proposing to authorize take for some 

cetacean species where the calculated 

Level A harassment take is significant, 

and the large PTS zone sizes could 

allow animals to enter into these zones 

without being observed by protected 

species observers (PSOs). 

A similar approach was employed to 

derive estimated take by Level B 

harassment. The Level B harassment 

zones are determined by taking the total 

area of the Level B harassment zones 

(54.99 km2; 20.78 km2; 5.27 km2; 0.07 

km2) and subtracting the Level A 

harassment areas as defined by activity 

type and hearing group. 

The Level B harassment zone area was 

multiplied by the highest density for a 

species (nearshore or offshore as 

described above) which was multiplied 

by the expected number of pile driving 

days for each activity type. The 

exposures for each activity were 

summed to arrive at the calculated Level 

B harassment take numbers as shown in 

Table 18. Additional detailed 

information may be found in Appendix 

B of the application. 


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TABLE 18—CALCULATED LEVEL A AND LEVEL B HARASSMENT EXPOSURES

Species 

Level A 

harassment 

total 

exposures 

Level B 

harassment 

total 

exposures 

Antarctic Minke Whale (LF) ..................................................................................................................................... 15.23 312.25 

Arnoux’s Beaked Whale (MF) ................................................................................................................................. 0.0001 0.14 

Blue Whale (LF) ....................................................................................................................................................... 0.0081 0.17 

Fin Whale (LF) ......................................................................................................................................................... 13.74 281.70 

Hourglass Dolphin (HF) ........................................................................................................................................... 0.32 4.94 

Humpback Whale (LF) ............................................................................................................................................. 5.91 121.21 

Killer Whale (MF) ..................................................................................................................................................... 0.04 111.70 

Long-finned Pilot Whale (MF) .................................................................................................................................. 0.01 28.19 

Southern Bottlenose Whale (MF) ............................................................................................................................ 0.009 23.55 

Sei Whale (LF) ......................................................................................................................................................... 0.04 0.84 

Southern Right Whale (LF) ...................................................................................................................................... 0.07 1.34 

Sperm Whale (MF) .................................................................................................................................................. 0.02 16.73 

Antarctic Fur Seal (OW) .......................................................................................................................................... 0.15 356.50 

Crabeater Seal (PW) ............................................................................................................................................... 119.07 6128.78 

Southern Elephant Seal (PW) ................................................................................................................................. 0.02 1.04 

Leopard Seal (PW) .................................................................................................................................................. 0.02 1.04 

Weddell Seal (PW) .................................................................................................................................................. 3.65 187.97 

In addition to considering density 

data presented in the literature, recent 

marine mammal observation data from 

Hero Inlet and nearby areas between 

January 21, 2019 and March 31, 2020 

are also considered in the take 

estimates. Observations within Hero 

Inlet near Palmer Station included 

animals observed in the waters of Hero 

Inlet, or hauled out at Gamage Point or 

Bonaparte Point. Gamage Point is 

approximately 100 m west of the pier 

area on Anvil Island while Bonaparte 

Point is located across Hero Inlet 135m 

southeast of the Pier area. Table 19 

shows a comparison between 

observational data from the Project Area 

(NSF, personal communication) and the 

calculated takes by Level A harassment 

based on density data. 

TABLE 19—COMPARISON OF OBSERVATION DATA FROM HERO INLET, GAMAGE POINT AND BONAPARTE POINT 2019–2020 

TO TOTAL LEVEL A HARASSMENT EXPOSURE ESTIMATES CALCULATED BASED ON DENSITY DATA

Species 

January 21– 

March 28, 

2019 

observations 

October 12, 

2019–March 

31, 2020 

observations 

Density-based 

total 

exposures 

Humpback Whale (LF) ................................................................................................................. 0 0 5.91 

Antarctic Fur Seal (OW) .............................................................................................................. 73 70 0.15 

Crabeater Seal (PW) ................................................................................................................... 20 24 119.07 

Southern Elephant Seal (PW) ..................................................................................................... 1 0 0.02 

Leopard Seal (PW) ...................................................................................................................... 3 2 0.02 

Weddell Seal (PW) ...................................................................................................................... 8 6 3.65 

Comparing the estimated exposures 

based on pinniped densities, number of 

days, and the Level A Harassment zone 

to local observational data from Palmer 

Station over two multiple-month 

periods suggests that some pinniped 

species were potentially observed at a 

greater rate than would be expected 

from density information. In the interest 

of generating a more conservative 

estimate that will ensure coverage for 

any marine mammals encountered, the 

number of Antarctic fur, leopard and 

Weddell seal takes have been increased 

to reflect the number individuals 

observed in Hero Inlet. 

Table 20 compares the number of 

calculated and proposed Level A and B 

harassment takes for each species. Level 

B harassment takes for Arnoux’s beaked 

whale, blue whale, hourglass dolphin, 

sei whale, and Southern right whale 

have been adjusted based on group size 

such that a higher level of Level B 

harassment take is proposed than was 

projected solely based on densities. 

Arnoux’s beaked whales often occur in 

groups of 6–10 and occasionally up to 

50 or more (Balcomb 1989). As a 

precautionary measure NSF requested 

and NMFS has proposed authorizing 12 

takes of this species by Level B 

harassment. Classified as HF cetaceans, 

these beaked whales have a relatively 

large Level A harassment zone that 

extends to as much as 4,149 m. 

However, calculated take by Level A 

harassment is fractional and 

furthermore, this is a deep diving and 

deep foraging species and it would be 

unlikely that animals would congregate 

in a Level A harassment zone long 

enough to accrue enough energy to 

experience PTS. Therefore, no Level A 

take was requested by NSF nor is 

proposed for authorization by NMFS. 

Blue whales are unlikely to be found in 

the Project Area. However, NSF 

requested and NMFS conservatively 

proposes to authorize two Level B 

harassment takes based on one average 

group size (NMFS, 2020). Hourglass 

Dolphins group size is generally 2–6 

individuals with groups of up to 25 

observed (Santora 2012). Classified as 

HF cetaceans, these dolphins have a 

relatively large Level A harassment zone 

that extends to 4,149 m. However, local 

observational data sets have not 

recorded a single animal and the species 

tends to be found in waters close to the 

Antarctic Convergence. Given this 

information NMFS proposes to 


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authorize 25 takes by Level B 

harassment which is a reduction from 

60 takes requested by NSF. Level A 

harassment takes are not expected or 

authorized since the dolphin species is 

highly mobile and is unlikely to remain 

in the zone long enough to experience 

PTS. Sei whales have an average group 

size of 6 (NMFS 2020) and generally 

inhabit continental shelf and slope 

waters far from coastlines. They are 

unlikely to occur but as a precautionary 

measure NSF has requested and NMFS 

proposes to authorize 6 takes by Level 

B harassment. Takes by Level A 

harassment are not expected or 

proposed for authorization. Southern 

right whales live in groups of up to 20 

individuals, but are more commonly 

found in groups of two or three, unless 

at feeding grounds. Observational 

surveys near Palmer Station did not 

record the presence of these whales. 

Therefore, NSF requested and NMFS 

conservatively proposes to authorize 20 

takes of Southern right whale by Level 

B harassment. No take by Level A 

harassment is anticipated or proposed 

for authorization. 

As discussed above, the proposed 

takes have been adjusted from the 

calculated takes based on observation 

data as summarized in Table 19. Local 

observers recorded 73 and 70 Antarctic 

fur seals in 2019 and 2020 respectively 

located in close proximity to the pier 

during months when construction 

would take place. As a precaution, the 

number of takes by Level A harassment 

requested by NSF and proposed for 

authorization by NMFS has been 

increased beyond the calculated density 

value to 80. Similarly, three leopard 

seals were observed in 2019 and two 

were recorded in 2020. To be 

precautionary, NSF requested and 

NMFS is proposing to authorize 5 

leopard seal takes by Level B. Further, 

since leopard seals are thought to be 

more likely to spend more time in the 

immediate vicinity (i.e., not as likely to 

travel through as the cetacean species 

discussed above) and potentially 

enough time in the Level A harassment 

zone to incur PTS, NMFS is also 

proposing to authorize 5 takes by Level 

A harassment. Finally, eight and six 

Weddell seals were observed in 2019 

and 2020, respectively. Given this 

information, and again to be 

precautionary NSF has requested and 

NMFS is proposing to authorize 10 takes 

by Level A harassment. Finally, NMFS 

has proposed a single take by Level A 

harassment of Southern elephant seal. 

Like all seals authorized for take there 

are driving scenarios where the PTS 

isopleth would be larger than 50-m 

pinniped shutdown zone. While only 

one elephant seal has been observed 

near Palmer Station, it could occur in 

the Level A harassment zone. 

TABLE 20—PROPOSED TAKES BY LEVEL A AND LEVEL B HARASSMENT COMPARED TO CALCULATED EXPOSURES

Species 

Calculated 

Level A 

harassment 

exposures 

Proposed 

Level A 

harassment 

take 

Calculated 

Level B 

harassment 

exposures 

Proposed 

Level B 

harassment 

take 

Takes as 

percent of 

abundance 

Antarctic Minke Whale (LF) ................................................. 15.23 15 312.25 312 1.80 

Arnoux’s Beaked Whale (MF) a ........................................... 0.00 0 0.14 12 Unknown 

Blue Whale (LF) a ................................................................. 0.01 0 0.17 2 0.12 

Fin Whale (LF) ..................................................................... 13.74 14 281.70 282 6.33 

Hourglass Dolphin (HF) a ..................................................... 0.32 0 4.94 25 0.01 

Humpback Whale (LF) ......................................................... 5.91 6 121.21 121 1.34 

Killer Whale (MF) ................................................................. 0.04 0 111.7 112 0.45 

Long-finned Pilot Whale (MF) .............................................. 0.01 0 28.19 28 0.01 

Southern Bottlenose Whale (MF) ........................................ 0.01 0 23.55 24 0.04 

Sei Whale (LF) a ................................................................... 0.04 0 0.84 6 0.96 

Southern Right Whale (LF) a ................................................ 0.07 0 1.34 20 1.13 

Sperm Whale (MF) .............................................................. 0.02 0 16.73 17 0.14 

Antarctic Fur Seal (OW) ...................................................... 0.15 b 80 356.5 357 0.02 

Crabeater Seal (PW) ........................................................... 119.07 120 6,128.78 6,129 0.12 

Southern Elephant Seal (PW) ............................................. 0.02 1 1.04 1 <0.01 

Leopard Seal (PW) .............................................................. 0.02 b 5 1.04 1 <0.01 

Weddell Seal (PW) .............................................................. 3.65 b 10 187.97 188 0.04 

a Level B harassment takes increased to account for group size assuming one group is encountered during the project. 

b Increased from calculated exposures due to local observational data. 

Table 20 also shows the proposed take 

by harassment for all species as a 

percentage of stock abundance. 

Proposed Mitigation 

In order to issue an IHA under section 

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

set forth the permissible methods of 

taking pursuant to 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, we carefully consider 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, 

impact on operations, and, in the case 


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of a military readiness activity, 

personnel safety, practicality of 

implementation, and impact on the 

effectiveness of the military readiness 

activity. 

The following mitigation measures are 

proposed in the IHA: 

• NSF must avoid direct physical 

interaction with marine mammals 

during construction activities. 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; 

• Training would occur between 

construction supervisors and crews and 

the PSO team and relevant NSF staff 

prior to the start of all pile driving and 

construction activities, and when new 

personnel join the work, in order to 

explain responsibilities, communication 

procedures, marine mammal monitoring 

protocol, and operational procedures are 

clearly understood; 

• Pile driving activities must be 

halted upon observation of 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, entering or within the harassment 

zone; 

• NSF will establish and implement a 

shutdown zone of 50 m for fur seals 

under all pile driving scenarios. 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 typically 

vary based on the activity type and 

marine mammal hearing group. 

Shutdown zones for cetaceans and other 

pinnipeds are based on Level A 

harassment isopleths shown in Table 

17. Based on observation data, fur seals 

are known to swim up Hero Inlet 

(approximately 135 m wide) to haul out. 

The proposed 50-m shutdown zone for 

fur seals can safely be observed, would 

prevent injury to seals while still 

allowing seals to move up the inlet 

where they may haul out on land, and 

would allow construction to continue 

safely and efficiently; 

• Shutdown zones have been 

established for all hearing groups under 

all driving scenarios as shown in Tables 

21 and 22 and are based on calculated 

Level A harassment zones; 

• Monitoring must take place from 30 

minutes prior to initiation of pile 

driving activity through 30 minutes 

post-completion of pile driving activity. 

Pre-start clearance monitoring must be 

conducted during periods of visibility 

sufficient for the lead PSO to determine 

the shutdown zones clear of marine 

mammals. Pile driving may commence 

following 30 minutes of observation 

when the determination is made; 

• If the Level A harassment shutdown 

zones are not visible due to poor 

environmental conditions (e.g., 

excessive wind or fog, high Beaufort 

state), pile installation would cease 

until the entirety of the Level A 

harassment shutdown zones is 

observable; 

• If pile driving is delayed or halted 

due to the presence of a marine 

mammal, the activity may not 

commence or resume until either the 

animal has voluntarily exited and been 

visually confirmed beyond the 

shutdown zone or 15 minutes have 

passed without re-detection of the 

animal; 

• If impact driving should be needed 

(i.e., for proofing) NSF must use soft 

start techniques when impact pile 

driving. Soft start requires contractors to 

provide an initial set of three strikes at 

reduced energy, followed by a 30- 

second waiting period, then two 

subsequent reduced-energy strike sets. 

A soft start must be implemented at the 

start of each day that begins with impact 

pile driving and at any time impact 

driving would occur after cessation of 

impact pile driving for a period of 30 

minutes or longer; 

• In-water construction would occur 

during daylight over a 12-hour workday 

to minimize the potential for PTS for 

species that may occur within the Level 

A harassment zones; and 

• When transiting to the site, marine 

mammal watches must be conducted by 

crew or those navigating the vessel. 

When in the Project Area, if a whale is 

sighted in the path of a support vessel 

or within 92 m (300 feet) from the 

vessel, NSF must reduce speed and 

must not engage the engines until the 

animals are clear of the area. If a whale 

is sighted farther than 92 m (300 feet) 

from the vessel, NSF must maintain a 

distance of 92 m (300 feet) or greater 

between the whale and the vessel and 

reduce speed to 10 knots or less. Vessels 

must not be operated in such a way as 

to separate members of a group of 

whales from other members of the 

group. A group is defined as being three 

or more whales observed within a 500 

m area and displaying behaviors of 

directed or coordinated activity (e.g., 

group feeding). 

TABLE 21—SHUTDOWN AND HARASSMENT ZONES (METERS) FOR NON-SIMULTANEOUS PILE INSTALLATION ACTIVITIES

Pile size, type, and method 

Minimum shutdown zone Level B 

harassment 

zone 

(m) 

Cetaceans Pinnipeds 

LF MF HF PW OW 

Dock, 36-in Dia. Pile Installation, 20′ 

Socket Depth—1 pile/day (DTH) .......... 1,900 70 2,255 1,015 50 11,659 

Dock Abutment, 36-in Dia. Pile Installation, 30′ Socket Depth—1 pile/day 

(DTH) .................................................... 2,500 90 2,955 1,330 

RHIB Fender Piles, 24-in Dia. Pile Installation, 20′ Socket—1 pile/day ............... 410 15 485 220 

24-in Dia. Template Piles, 10′ Socket 

Depth—2 piles/day.

24-in Dia. Wave Attenuator Piles, 20′ 

Socket Depth—1 pile/day.

Retaining Wall HP Pile inserted in Drilled 

24-in Dia. Sockets, 20′ Socket Depth— 

1 pile/day.

Removal of 24-in Dia. Template Piles— 

16 piles ................................................. 55 10 75 35 10,000 

Removal of Sheet Piles ........................... 25 35 15 4,642 

Rock Chipping/Floor Preparation ............. 405 50 720 205 123 


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TABLE 21—SHUTDOWN AND HARASSMENT ZONES (METERS) FOR NON-SIMULTANEOUS PILE INSTALLATION ACTIVITIES— 

Continued 

Pile size, type, and method 

Minimum shutdown zone Level B 

harassment 

zone 

(m) 

Cetaceans Pinnipeds 

LF MF HF PW OW 

Anode Installation .................................... 10 10 10 10 200 

TABLE 22—SHUTDOWN AND HARASSMENT ZONES (METERS) FOR SIMULTANEOUS PILE INSTALLATION ACTIVITIES

Daily activity scenario 

Minimum shutdown zone Level B 

harassment 

zone 

(m) 

Cetaceans Pinnipeds 

LF MF HF PW OW 

Dock, 36-in Dia. Pile Installation, 20′ 

Socket Depth—2 pile/day ..................... 3,500 110 3,580 1,610 50 18,478 

Dock Abutment, 36-in Dia. Pile Installation, 30′ Socket Depth and 36-in Dia. 

Pile 20′ Socket Depth .......................... 125 4,150 1,865 

RHIB Fender Piles, 24-in Dia. Pile Installation, 20′ Socket—2 pile/day ............... 650 25 770 350 

24-in Dia. Template Piles, 10′ Socket 

Depth—4 piles/day.

24-in Dia. Wave Attenuator Piles, 20′ 

Socket Depth—2 pile/day.

Retaining Wall—HP Pile inserted in 

Drilled 24-in Dia. Sockets, 20′ Socket 

Depth—2 piles/day.

Dock, 36-in Dia. Pile Installation, 20′ 

Socket Depth—1 pile/day and Wave 

Attenuator, 24-in Dia. Pile Installation, 

20′ Socket—1 pile/day ......................... 2,050 75 2,400 1,080 

Dock 36-in Dia. Pile Installation 30′ 

Socket Depth and 24-in Dia. Pile Installation 20′ Socket Depth .................. 2,900 105 3,500 1,545 

36-in Dock 20′ socket x 2 Dock Abutment ...................................................... 45 10 65 30 34,146 

RHIB Fender Piles 24-in x 2 .................... 20 30 10 15,849 

24-in template 10′ socket x 4.

24-in wave attenuator piles-10′ socket x 

2 ............................................................ 35 50 

24-in wave attenuator piles-20′ socket x 

2 ............................................................ 35 50 

Based on our evaluation of the 

applicant’s proposed measures, as well 

as other measures considered by NMFS, 

NMFS has preliminarily determined 

that the proposed mitigation measures 

provide the means effecting the least 

practicable impact on the affected 

species or stocks and their habitat, 

paying particular attention to rookeries, 

mating grounds, and areas of similar 

significance. 

Proposed Monitoring and Reporting 

In order to issue an IHA for an 

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

MMPA states that NMFS must set forth 

requirements pertaining to the 

monitoring and reporting of such taking. 

The MMPA implementing regulations at 

50 CFR 216.104 (a)(13) indicate that 

requests for authorizations must include 

the suggested means of accomplishing 

the necessary monitoring and reporting 

that will result in increased knowledge 

of the species and of the level of taking 

or impacts on populations of marine 

mammals that are expected to be 

present in the proposed Project Area. 

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 

action; 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). 

• Mitigation and monitoring 

effectiveness. 

Visual Monitoring 

One NMFS-approved, formally 

trained PSO with prior experience 

performing the duties of a PSO during 

construction activities would serve as 

team leader, supported by three PSOs 

trained on site or through available 

online training programs compliant 

with NMFS standards. PSOs must be 

independent (i.e., not construction 

personnel) and have no other assigned 

tasks during monitoring periods. Prior 

to initiation of construction, PSOs 

would complete a training/refresher 

session on marine mammal monitoring, 

to be conducted shortly before the 

anticipated start of the open water 

season construction activities. 

Primary objectives of the training 

session include: 

• Review of the mitigation, 

monitoring, and reporting requirements 

provided in the application and IHA, 

including any modifications specified 

by NMFS in the authorization; 

• Review of marine mammal sighting, 

identification, and distance estimation 

methods; 

• Review of operation of specialized 

equipment (bigeye binoculars, GPS); 

and 

• Review of, and classroom practice 

with, data recording and data entry 

systems, including procedures for 

recording data on marine mammal 

sightings, monitoring operations, 

environmental conditions, and entry 

error control. 

PSOs must have the following 

additional qualifications: 

• Ability to conduct field 

observations and collect data according 

to assigned protocols; 

• Experience or training in the field 

identification of marine mammals, 

including the identification of 

behaviors; 

• Sufficient training, orientation, or 

experience with the construction 

operation to provide for personal safety 

during observations; 

• Writing skills sufficient to prepare a 

report of observations including but not 

limited to the number and species of 

marine mammals observed; dates and 

times when in-water construction 

activities were conducted; dates, times, 

and reason for implementation of 

mitigation (or why mitigation was not 

implemented when required); and 

marine mammal behavior; and 

• Ability to communicate orally, by 

radio or in person, with project 

personnel to provide real-time 

information on marine mammals 

observed in the area as necessary. 

Two PSOs must be on duty during all 

in-water construction activities and 

must record all observations of marine 

mammals regardless of distance from 

the pile being driven or covered activity. 

PSOs shall document any behavioral 

reactions in concert with distance from 

piles being driven or removed. PSOs are 

limited to monitoring no more than 4 

hours per shift with sufficient breaks 

and no more than 12 hours per day to 

minimize fatigue. 

The placement of PSOs during all pile 

driving and removal and drilling 

activities will ensure that the entire 

shutdown zones are visible during pile 

installation. Should environmental 

conditions deteriorate such that marine 

mammals within the entire shutdown 

zone will not be visible (e.g., fog, heavy 

rain), pile driving and removal must be 

delayed until the PSO is confident 

marine mammals within the shutdown 

zone could be detected. The primary 

monitoring location currently proposed 

by NSF would be on the roof platform 

of the Garage Warehouse Recreation 

(GWR) building (approximately 20 

meters above sea level) to provide visual 

coverage of the Level A shutdown 

zones. NMFS agrees that the GWR 

building is an appropriate monitoring 

location. The primary PSO can monitor 

the Project Area generally southsoutheast while the second PSO can 

monitor the area generally westsouthwest that may be ensonified. With 

reticle binoculars the distance 

potentially visible by a 1.8-m tall PSO 

from this point would be about 4,360 m. 

Mounted big eye binoculars would be 

provided to PSOs to better cover the 

Level A harassment zone. NSF believes 

this location and is adequate to fully 

monitor the Level A harassment and 

shutdown zones, however, we note that 

sea state, glare, observer expertise, and 

other factors can affect the ability of 

PSOs to see and identify marine 

mammals to hearing group at such large 

distances, even if those distances are 

theoretically observable. Local 

researchers have reported that very little 

of some level B harassment zones will 

be visible (Ari Friedlander, personal 

communication). 

Palmer Station normally has 2.8 meter 

RHIBs, 2 4.8 m RHIBs, and a number of 

smaller boats that are normally available 

and used on a daily basis in areas 

within 2–3 miles of the station (Ari 

Friedlander, personal communication). 

NSF has stated that PSOs in boats that 

would monitor the outer part of the 

Level A or Level B harassment zones are 

not practicable because the remote 

location of the Project Area presents 

both safety and logistical challenges. 

Given the comparatively limited 

information regarding the species in this 

area and the likely impacts of 

construction activities on the species in 

this area, NMFS is specifically 

requesting public comment on the 

proposed monitoring and mitigation 

requirements. 

Reporting 

A draft marine mammal monitoring 

report will be submitted to NMFS 

within 90 days after the completion of 

pile driving and removal activities, or 

60 days prior to a requested date of 

issuance of any future IHAs for projects 

at the same location, whichever comes 

first. The report will include an overall 

description of work completed, a 

narrative regarding marine mammal 

sightings, and associated PSO data 

sheets. Specifically, the report must 

include: 

• Dates and times (begin and end) of 

all marine mammal monitoring; 

• Construction activities occurring 

during each daily observation period, 

including the number and type of piles 

driven or removed and by what method 

(i.e., impact or cutting) and the total 

equipment duration for cutting for each 

pile or total number of strikes for each 

pile (impact driving); 

• PSO locations during marine 

mammal monitoring; 

• 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; 

• Upon observation of a marine 

mammal, 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 bearing of each marine 

mammal observed relative to the pile 

being driven for each sighting (if pile 

driving was occurring at time of 

sighting); Estimated number of animals 

(min/max/best estimate); Estimated 

number of animals by cohort (adults, 

juveniles, neonates, group composition, 

etc.); Animal’s closest point of approach 

and estimated time spent within the 

harassment zone; Description of any 


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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 any 

implementation of any mitigation 

triggered (e.g., shutdowns and delays), a 

description of specific actions that 

ensued, and resulting changes in 

behavior of the animal(s), if any. 

If no comments are received from 

NMFS within 30 days, the draft final 

report will constitute the final report. If 

comments are received, a final report 

addressing NMFS comments must be 

submitted within 30 days after receipt of 

comments. 

Reporting Injured or Dead Marine 

Mammals 

In the event that personnel involved 

in the construction activities discover 

an injured or dead marine mammal, the 

IHA-holder must immediately cease the 

specified activities and report the 

incident to the Office of Protected 

Resources (PR.ITP.MonitoringReports@

noaa.gov), NMFS as soon as feasible. If 

the death or injury was clearly caused 

by the specified activity, NSF must 

immediately cease the specified 

activities until NMFS 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 the IHA. 

The IHA-holder must not resume their 

activities until notified by NMFS. The 

report must include the following 

information: 

• Time, date, and location (latitude/ 

longitude) of the first discovery (and 

updated location information if known 

and applicable); 

• Species identification (if known) or 

description of the animal(s) involved; 

• Condition of the animal(s) 

(including carcass condition if the 

animal is dead); 

• Observed behaviors of the 

animal(s), if alive; 

• 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 responses (e.g., intensity, 

duration), the context of any responses 

(e.g., critical reproductive time or 

location, migration), 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’s 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 environmental 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). 

DTH pile installation, vibratory pile 

removal, limited impact pile driving for 

proofing, rock chipping and use of a 

hydrogrinder have the potential to 

disturb or displace marine mammals. 

Specifically, the project activities may 

result in take, in the form of Level A and 

Level B harassment from underwater 

sounds generated from pile driving 

activities. Potential takes could occur if 

individuals are present in the ensonified 

zone when these activities are 

underway. 

The takes from Level A and Level B 

harassment would be due to potential 

PTS, TTS and behavioral disturbance. 

Even absent mitigation, no mortality or 

serious injury is anticipated given the 

nature of the activity and construction 

method. The potential for harassment 

would be further minimized through the 

implementation of the planned 

mitigation measures (see Proposed 

Mitigation section). 

Effects on individual animals that are 

taken by Level B harassment, on the 

basis of reports in the literature as well 

as monitoring from other similar 

activities, will likely be limited to 

reactions such as increased swimming 

speeds, increased surfacing time, or 

decreased foraging (if such activity were 

occurring) (e.g., Thorson and Reyff 

2006; HDR Inc. 2012; Lerma 2014; ABR 

2016). Most likely, individuals will 

simply move away from the sound 

source and be temporarily displaced 

from the areas of pile installation, 

although even this reaction has been 

observed primarily only in association 

with impact pile driving. If sound 

produced by project activities is 

sufficiently disturbing, animals are 

likely to simply avoid the area while the 

activity is occurring. While DTH pile 

installation associated with the 

proposed project may produce sound at 

distances of many kilometers from the 

project site, we expect that animals 

annoyed by project sound would simply 

avoid the area and use more-preferred 

habitats. Furthermore, during any 

impact driving, implementation of soft 

start procedures will be required and 

monitoring of established shutdown 

zones will be required for all pile 

installation and removal activities, 

significantly reducing the possibility of 

injury. Use of impact driving will be 

limited to proofing of piles after they 

have been set in place. Given sufficient 

notice through use of soft start (for 

impact driving), marine mammals are 

expected to move away from an 

irritating sound source prior to it 

becoming potentially injurious. This 

sort of low-level localized displacement, 

in the absence of any specific known 

biologically important areas, would not 

be expected to impact the reproduction 

or survival of any individuals. 

In addition to the expected effects 

resulting from authorized Level B 

harassment, we anticipate that Antarctic 

minke whales, fin whales, and 

humpback whales may sustain some 

limited Level A harassment in the form 

of auditory injury due to large PTS 

zones for LF cetaceans. We are also 

proposing to authorize take by Level A 

harassment of Antarctic fur seals, 

crabeater seals, leopard seals, Weddell 

seals, and Southern elephant seals since 

the Level A harassment zones are large 

relative to the ability to detect low 

profile, species that are common in the 

region. However, animals that 

experience PTS would likely be 

subjected to 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 regions of greatest 

hearing sensitivity. If hearing 

impairment occurs, it is most likely that 

the affected animal would lose a few 

decibels in its hearing sensitivity, which 

in most cases is not likely to 


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meaningfully affect its ability to forage 

and communicate with conspecifics. 

The project is also not expected to 

have significant adverse effects on 

affected marine mammals’ habitats. The 

project activities would not modify 

existing marine mammal habitat for a 

significant amount of time. The 

activities may cause some fish to leave 

the area of disturbance, thus temporarily 

impacting marine mammals’ foraging 

opportunities in a limited portion of the 

foraging range; but, because of the 

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 for marine mammals. 

The nature of NSF’s proposed 

construction activities precludes the 

likelihood of serious injury or mortality, 

even absent mitigation. For all species 

and stocks, take would occur within a 

limited area (Hero Inlet and nearby 

waters) that constitutes a small portion 

of the ranges for authorized species. 

Level A and Level B harassment will be 

reduced to the level of least practicable 

adverse impact through use of 

mitigation measures described herein. 

Further, the amount of take proposed to 

be authorized is extremely small when 

compared to stock abundance of 

authorized species. 

In summary and as described above, 

the following factors primarily support 

our preliminary 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 or serious injury is 

anticipated or authorized; 

• The relatively small number of 

Level A harassment exposures are 

anticipated to result only in slight PTS 

within the lower frequencies associated 

with pile driving; 

• The anticipated incidents of Level B 

harassment would consist of, at worst, 

temporary modifications in behavior 

that would not result in fitness impacts 

to individuals; 

• No adverse effects on affected 

marine mammals’ habitat are 

anticipated; 

• No important habitat areas have 

been identified within the Project Area; 

• For all species, Hero Inlet and 

nearby waters represent very small and 

peripheral part of their ranges; and 

• The required mitigation measures 

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

effective in reducing the effects of the 

specified activity. 

Based on the analysis contained 

herein of the likely effects of the 

specified activity on marine mammals 

and their habitat, and taking into 

consideration the implementation of the 

proposed monitoring and mitigation 

measures, NMFS preliminarily finds 

that the total marine mammal take from 

the proposed activity will have a 

negligible impact on all affected marine 

mammal species or stocks. 

Small Numbers 

As noted above, 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. 

The amount of take NMFS proposes to 

authorize is below one third of the 

estimated stock abundances for all 17 

species. For all requested species, the 

proposed take of individuals is less than 

6.4 percent of the abundance of the 

affected species or stock as shown in 

Table 20. This is likely a conservative 

estimate because it assumes all take are 

of different individual animals, which is 

likely not the case. Some individuals 

may return multiple times in a day, but 

PSOs would count them as separate 

takes if they cannot be individually 

identified. 

Based on the analysis contained 

herein of the proposed activity 

(including the proposed mitigation and 

monitoring measures) and the 

anticipated take of marine mammals, 

NMFS preliminarily 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 would not have an unmitigable 

adverse impact on the availability of 

such species or stocks for taking for 

subsistence purposes. 

Endangered Species Act 

Section 7(a)(2) of the Endangered 

Species Act of 1973 (ESA: 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 

IHAs, NMFS consults internally 

whenever we propose to authorize take 

for endangered or threatened species, in 

this case with the ESA Interagency 

Cooperation Division. 

NMFS is proposing to authorize take 

of blue whale, fin whale, sei whale, 

Southern right whale, and sperm whale, 

which are listed as endangered under 

the ESA. 

The Permit and Conservation Division 

has requested initiation of Section 7 

consultation with the Interagency 

Cooperation Division for the issuance of 

this IHA. NMFS will conclude the ESA 

consultation prior to reaching a 

determination regarding the proposed 

issuance of the authorization. 

Proposed Authorization 

As a result of these preliminary 

determinations, NMFS proposes to issue 

an IHA to NSF to conduct the Palmer 

Station Pier Replacement project at 

Anvers Island, Antarctica, provided the 

previously mentioned mitigation, 

monitoring, and reporting requirements 

are incorporated. A draft of the 

proposed IHA can be found at https:// 

www.fisheries.noaa.gov/permit/ 

incidental-take-authorizations-undermarine-mammal-protection-act. 

Request for Public Comments 

We request comment on our analyses, 

the proposed authorization, and any 

other aspect of this notice of proposed 

IHA for the proposed Palmer Station 

Pier Replacement project. We also 

request at this time comment on the 

potential Renewal of this proposed IHA 

as described in the paragraph below. 

Please include with your comments any 

supporting data or literature citations to 

help inform decisions on the request for 

this IHA or a subsequent Renewal IHA. 

On a case-by-case basis, NMFS may 

issue a one-time, one-year Renewal IHA 

following notice to the public providing 

an additional 15 days for public 

comments when (1) up to another year 

of identical or nearly identical, or nearly 

identical, activities as described in the 

Description of Proposed Activities 

section of this notice is planned or (2) 

the activities as described in the 


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Description of Proposed Activities 

section of this notice would not be 

completed by the time the IHA expires 

and a Renewal would allow for 

completion of the activities beyond that 

described in the Dates and Duration 

section of this notice, provided all of the 

following conditions are met: 

• A request for renewal is received no 

later than 60 days prior to the needed 

Renewal IHA effective date (recognizing 

that the Renewal IHA expiration date 

cannot extend beyond one year from 

expiration of the initial IHA); 

• The request for renewal must 

include the following: 

(1) An explanation that the activities 

to be conducted under the requested 

Renewal IHA are identical to the 

activities analyzed under the initial 

IHA, are a subset of the activities, or 

include changes so minor (e.g., 

reduction in pile size) that the changes 

do not affect the previous analyses, 

mitigation and monitoring 

requirements, or take estimates (with 

the exception of reducing the type or 

amount of take); and 

(2) A preliminary monitoring report 

showing the results of the required 

monitoring to date and an explanation 

showing that the monitoring results do 

not indicate impacts of a scale or nature 

not previously analyzed or authorized; 

and 

Upon review of the request for 

Renewal, the status of the affected 

species or stocks, and any other 

pertinent information, NMFS 

determines that there are no more than 

minor changes in the activities, the 

mitigation and monitoring measures 

will remain the same and appropriate, 

and the findings in the initial IHA 

remain valid. 

Dated: August 13, 2021. 

Shannon Bettridge, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2021–17725 Filed 8–17–21; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XA720] 

Fisheries of the Northeastern United 

States; Northeast Multispecies 

Fishery; Receipt of Petition for 

Rulemaking for Atlantic Cod 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Announcement of receipt of 

petition for rulemaking; request for 

comments. 

SUMMARY: NMFS announces the receipt 

of a petition for rulemaking from the 

Conservation Law Foundation. This 

petition requests NMFS prepare a 

Secretarial Amendment and take 

specific emergency action to end 

overfishing and rebuild Atlantic cod. 

DATES: Comments must be received on 

or before October 4, 2021. 

ADDRESSES: You may submit comments, 

identified by NOAA–NMFS–2021–0039, 

by either of the following methods: 

• Electronic Submission: Submit all 

electronic public comments via the 

Federal e-Rulemaking Portal. Go to 

http://www.regulations.gov and enter 

NOAA–NMFS–2021–0039 in the Search 

box. Click on the ‘‘Comment’’ icon, 

complete the required fields, and enter 

or attach your comments. 

Instructions: Comments sent by any 

other method, to any other address or 

individual, or received after the end of 

the comment period, may not be 

considered by NMFS. All comments 

received are a part of the public record 

and will generally be posted for public 

viewing on www.regulations.gov 

without change. All personal identifying 

information (e.g., name, address, etc.), 

confidential business information, or 

otherwise sensitive information 

submitted voluntarily by the sender will 

be publically accessible. NMFS will 

accept anonymous comments (enter 

‘‘N/A’’ in the required fields if you wish 

to remain anonymous). 

FOR FURTHER INFORMATION CONTACT: 

Peter Christopher, Supervisory Fishery 

Policy Analyst, telephone 978–281– 

9288, email: peter.christopher@

noaa.gov. 

SUPPLEMENTARY INFORMATION: The 

Conservation Law Foundation (CLF) has 

petitioned NMFS to implement 

emergency regulations and a Secretarial 

Amendment for the Northeast 

multispecies fishery, and other relevant 

fisheries that use gear capable of 

catching more than a minimal amount 

of Atlantic cod. CLF’s petition asserts 

that NMFS has repeatedly approved 

New England Fishery Management 

Council actions that have failed to 

prevent and end overfishing and rebuild 

Atlantic cod stocks. CLF is petitioning 

NMFS to implement conservation and 

management measures it deems 

necessary to end overfishing and rebuild 

the Gulf of Maine and Georges Bank cod 

stocks. 

CLF cites numerous reasons for NMFS 

to take Secretarial action. CLF asserts 

that NMFS has consistently approved 

management measures that failed to 

address low recruitment, neglected to 

account for model errors and 

uncertainty when setting catch advice, 

approved uncertainty buffers that do not 

account for this uncertainty, and 

approved the use of an inadequate 

acceptable biological catch (ABC) 

control rule. In addition, CLF states that 

NMFS has failed to conduct adequate 

rebuilding progress reviews for both the 

Gulf of Maine and Georges Bank cod 

stocks as required under the MagnusonStevens Fishery Conservation and 

Management Act (Magnuson-Stevens 

Act), or as required by the supplemental 

rebuilding program review process 

implemented in Framework Adjustment 

51 to the Northeast Multispecies Fishery 

Management Plan (FMP). This review 

process requires the Council to review 

a rebuilding plan if: The total catch 

limit for a stock has not been exceeded 

during the rebuilding program; new 

scientific information indicates that the 

stock is not rebuilding according to the 

program trajectory; and if the fishing 

mortality associated with rebuilding 

(Frebuild) drops below 75 percent of the 

fishing mortality associated with 

maximum sustainable yield (FMSY)). 

According to CLF, the Gulf of Maine cod 

stock has met all three of these criteria, 

but the Council has not initiated its 

required rebuilding program review. 

Further, CLF asserts that NMFS has 

failed to recognize or account for the 

findings of a National Research Council 

(NRC) Rebuilding Committee, which 

identified several reasons why stocks 

may not rebuild as expected under their 

respective rebuilding plans. Finally, 

CLF states that in NMFS’s denial of a 

2015 petition for rulemaking on Gulf of 

Maine cod, NMFS committed to prevent 

overfishing, rebuild the stock, and 

adjust management measures as needed 

in response to the findings of a 2015 

assessment. CLF asserts that these 

commitments were not upheld, and that 

NMFS did not properly balance 

biological and socioeconomic impacts 

in its rationale to deny the 2015 

petition. 

CLF’s petition also alleges that 

inadequate at-sea monitoring coverage 

in the sector fishery has failed to 

provide sufficiently accurate and 

precise data to prevent and end 

overfishing or rebuild the cod stocks. 

CLF asserts that inadequate monitoring 

coverage targets, coupled with low 

quotas, have created incentives for the 

fishing industry to illegally discard and 

misreport cod catch. Additionally, CLF 

relies on recent analyses in the 

development of Amendment 23 to the 

Northeast Multispecies FMP indicating 


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