30418 Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 

mammals observed during the course of 

construction. The report must include 

an extrapolation of the estimated takes 

by Level B harassment based on the 

number of observed disturbances within 

the Level B harassment zone and the 

percentage of time the Level B 

harassment zone was not monitored; 

i.e., 50 percent of time for the two 

restoration areas and 80 percent of the 

time for the borrow and other areas. If 

comments are received from the NMFS 

Office of Protected Resources on the 

draft report, a final report shall be 

submitted to NMFS within 30 days 

thereafter following resolution of 

comments on the draft report from 

NMFS. If no comments are received 

from NMFS, the draft report will be 

considered to be the final report. This 

report must contain the informational 

elements described above. 

Comments and Responses 

As noted previously, NMFS published 

a notice of a proposed IHA (84 FR 

72308; December 31, 2019) and solicited 

public comments on both our proposal 

to issue the initial IHA for CDFW’s 

activity and on the potential for a 

Renewal IHA, should certain 

requirements be met. All public 

comments were addressed in the notice 

announcing the issuance of the initial 

IHA (85 FR 14640; March 13, 2020). 

Below, we describe how we have 

addressed, with updated information 

where appropriate, any comments 

received that specifically pertain to the 

Renewal of the 2020 IHA. 

Comment: The Commission reiterated 

programmatic recommendations 

regarding NMFS’ potential use of the 

renewal mechanism for 1 year IHAs; 

that NMFS refrain from issuing 

renewals for any authorization and 

instead use its abbreviated Federal 

Register notice process. 

Response: In prior responses to 

comments about IHA Renewals (e.g., 84 

FR 52464; October 02, 2019 and 85 FR 

53342, August 28, 2020), NMFS has 

explained how the Renewal process, as 

implemented, is consistent with the 

statutory requirements contained in 

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

provides additional efficiencies beyond 

the use of abbreviated notices, and, 

further, promotes NMFS’ goals of 

improving conservation of marine 

mammals and increasing efficiency in 

the MMPA compliance process. 

Therefore, we intend to continue 

implementing the Renewal process. 

Preliminary Determinations 

NMFS has preliminarily concluded 

that there is no new information 

suggesting that our analysis or findings 

should change from those reached for 

the initial IHA. Based on the 

information and analysis contained here 

and in the referenced documents, NMFS 

has determined the following: (1) The 

required mitigation measures will effect 

the least practicable impact on marine 

mammal species or stocks and their 

habitat; (2) the authorized takes will 

have a negligible impact on the affected 

marine mammal species or stocks; (3) 

the authorized takes represent small 

numbers of marine mammals relative to 

the affected stock abundances; (4) 

CDFW activities will not have an 

unmitigable adverse impact on taking 

for subsistence purposes as no relevant 

subsistence uses of marine mammals are 

implicated by this action, and; (5) 

appropriate monitoring and reporting 

requirements are included. 

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. 

No incidental take of ESA-listed 

species is proposed for authorization or 

expected to result from this activity in 

the Elkhorn Slough Reserve. Therefore, 

NMFS has determined that formal 

consultation under section 7 of the ESA 

is not required for this action. 

Proposed Renewal IHA and Request for 

Public Comment 

As a result of these preliminary 

determinations, NMFS proposes to issue 

a Renewal IHA to CDFW for conducting 

Phase II of the Elkhorn Slough Tidal 

Marsh Restoration Project in Elkhorn 

Slough located in Monterey County, 

California, provided the previously 

described mitigation, monitoring, and 

reporting requirements are incorporated. 

A draft of the proposed and final initial 

IHA can be found at https://

www.fisheries.noaa.gov/permit/ 

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

request comment on our analyses, the 

proposed Renewal IHA, and any other 

aspect of this notice. Please include 

with your comments any supporting 

data or literature citations to help 

inform our final decision on the request 

for MMPA authorization. 

Dated: June 2, 2021. 

Catherine Marzin, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2021–11915 Filed 6–7–21; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XB146] 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to Portsmouth 

Naval Shipyard Dry Dock 1 

Modification and Expansion 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; issuance of incidental 

harassment authorization. 

SUMMARY: In accordance with the 

regulations implementing the Marine 

Mammal Protection Act (MMPA) as 

amended, notification is hereby given 

that NMFS has issued an IHA to the 

U.S. Navy (Navy) to incidentally harass, 

by Level B and Level A harassment, 

marine mammals incidental to 

Portsmouth Naval Shipyard (PNSY) Dry 

Dock 1 (DD1) modification and 

expansion in Kittery, Maine. 

DATES: This authorization is effective 

from June 2, 2021 through June 1, 2022. 

FOR FURTHER INFORMATION CONTACT: 

Carter Esch, Office of Protected 

Resources, NMFS, (301) 427–8421. 

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 


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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 such species or stocks for 

taking for certain subsistence uses 

(referred to here as ‘‘mitigation’’). 

Monitoring and reporting of such 

takings are also required. The meaning 

of key terms such as ‘‘take,’’ 

‘‘harassment,’’ and ‘‘negligible impact’’ 

can be found in section 3 of the MMPA 

(16 U.S.C. 1362 and the agency’s 

regulations at 50 CFR 216.103. 

Summary of Request 

On October 22, 2020, NMFS received 

a request from the Navy for an IHA to 

take marine mammals incidental to 

modification and expansion of DD1 at 

PNSY in Kittery, Maine. The Navy 

submitted revised versions of the 

application on December 30, 2020, and 

January 19 and February 11, 2021. The 

application was deemed adequate and 

complete on February 19, 2021. The 

Navy’s request is for take of a small 

number of harbor porpoises, harbor 

seals, gray seals, harp seals, and hooded 

seals by Level B harassment and Level 

A harassment for a subset of these 

species. Neither the Navy nor NMFS 

expects serious injury or mortality to 

result from this activity; therefore, an 

IHA is appropriate. 

NMFS previously issued three IHAs 

to the Navy for waterfront improvement 

work, in 2016 (81 FR 85525; November 

28, 2016), 2018 (83 FR 3318; January 24, 

2018), 2019 (84 FR 24476, May 28, 

2019), and a renewal of the 2019 IHA 

(86 FR 14598; March 17, 2021). As 

required, the applicant provided 

monitoring reports (available at: https:// 

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/incidentaltake-authorizations-constructionactivities) which confirm that the 

applicant has implemented the required 

mitigation and monitoring, and which 

also shows that no impacts of a scale or 

nature not previously analyzed or 

authorized have occurred as a result of 

the activities conducted. This IHA 

covers the second year of a larger fiveyear project, for which the Navy also 

intends to request take authorization for 

subsequent dock modification and 

expansion at the PNSY. 

Description of the Specified Activity 

As part of its overall objective to 

modernize and maximize dry dock 

capabilities for performing current and 

future missions efficiently and with 

maximum flexibility, the Navy plans to 

modify and expand DD1 at the PNSY by 

constructing two new dry docking 

positions capable of servicing Virginia 

class submarines within the super flood 

basin of the dry dock. The in-water 

portion of the dock modification and 

expansion, which will occur within and 

at the boundaries of the super flood 

basin, includes: Construction of the 

west closure wall, construction of 

entrance structure closure walls, and 

bedrock excavation. Construction 

activities include in-water impact pile 

driving, vibratory pile driving and 

removal, rock drilling, and underwater 

blasting. Underwater sounds produced 

by these activities may result in Level B 

harassment and Level A harassment of 

marine mammal species. 

In-water construction activities are 

expected to occur between June 2021 

and June 2022, with an estimated total 

of 29 days for pile driving and pile 

removal, 130 days for drilling of blast 

charge holes, and 130 days of blasting 

for bedrock excavation, for a total of 289 

construction days. Some of these 

activities will occur on the same day, 

resulting in 159 total construction days 

over 12 months. However, as a 

conservative measure, construction days 

are accounted for as consecutive rather 

than concurrent activities in take 

estimates (see Estimated Take section). 

All in-water construction work will be 

limited to daylight hours, with the 

exception of pre-dawn (beginning no 

earlier than 3:00 a.m.) drilling of blast 

charge holes; drilling will not occur 

from sunset to pre-dawn. The daily 

construction timeframe for blasting will 

begin no sooner than 30 minutes after 

sunrise to allow for initial marine 

mammal monitoring to take place and 

will end at least 60 minutes before 

sunset to allow for post-activity 

monitoring. 

A summary of in-water pile driving 

activity is provided in Table 1. In 

addition, a total of 1,580, 4.5-inch blast 

charge holes will be drilled at a rate of 

12 holes per day over 130 days. The 

Navy anticipates one to two blast events 

per day, with a maximum of 6 blast 

events per week; a total of 150 blast 

events will occur over 130 days. 

TABLE 1—SUMMARY OF IN-WATER PILE DRIVING ACTIVITIES

Pile purpose Pile type Pile size 

(inch) Pile drive method Total piles Piles/day Work days 

West closure wall template ................. Steel pipe ............ 30 Vibratory .............. 13 installed .......... 3 5 

13 removed ......... 3 5 

West closure wall construction ........... Flat-webbed steel 

sheet.

18 Vibratory .............. 160 ...................... 12 13 

Impact.

Entrance structure temporary guide 

dolphin removal.

Steel pipe ............ 30 Vibratory .............. 12 ........................ 8 2 

Entrance structure closure wall construction.Steel sheet .......... 28 Vibratory .............. 44 ........................ 12 4 

Impact.

Total ............................................. ............................. .................... ............................. 242 ...................... .................... 29 

Construction activities will occur at 

the PNSY in Kittery, Maine. Please see 

Figures 1–1 to 1–6 in the Navy’s IHA 

application for detailed maps of the 

project area and super flood basin. A 

detailed description of the planned 

modification and expansion of DD1 is 

provided in the Federal Register notice 

for the proposed IHA (86 FR 18244; 

April 8, 2021). Since that time, no 

changes have been made to the planned 

activities. Therefore, a detailed 


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description is not provided here. Please 

refer to that Federal Register notice and 

the original proposed IHA documents 

referenced therein for a detailed 

description of the specified activity. 

Comments and Responses 

A notice of NMFS’ proposal to issue 

an IHA to the Navy was published in 

the Federal Register on April 8, 2021 

(86 FR 18244). That notice described, in 

detail, the Navy’s activity, the marine 

mammal species that may be affected by 

the activity, and the anticipated effects 

on marine mammals. During the 30-day 

public comment period, NMFS received 

comments from the Marine Mammal 

Commission (Commission). For full 

details of the comments, please see the 

Commission’s letter, which is available 

online at: https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/incidentaltake-authorizations-constructionactivities#active-authorizations. A 

summary of the Commission’s 

recommendations as well as NMFS’ 

responses is below. 

Comment 1: As a result of its belief 

that NMFS did not provide the public 

with an adequate basis for review of 

NMFS’ proposed action, due to what it 

asserts are errors in the notice of the 

proposed authorization, the 

Commission recommends that NMFS 

either deny the proposed incidental 

harassment authorization or publish a 

revised Federal Register notice and 

draft authorization with another 30-day 

comment period. 

Response: NMFS does not agree with 

the Commission and does not adopt the 

recommendation. Although the initial 

Federal Register notice and proposed 

authorization contained certain errors 

and omissions, which have been 

addressed in this notice and 

authorization according to the 

Commission’s recommendations, the 

description of the specified activity and 

analysis of potential acoustic impacts on 

marine mammals in the vicinity of the 

project area in the notice of the 

proposed authorization (86 FR 18422; 

April 8, 2021) provided sufficient 

information upon which to determine 

whether or not the activities would have 

a negligible impact on the species or 

stocks for which take is likely to occur, 

and on which the public had an 

opportunity to comment. The 

information utilized in take estimation 

(i.e., source levels, thresholds, densities, 

and number of construction days for 

each specified activity) has largely been 

retained from the proposed to the final 

authorization, with the exception of 

revised source levels for impact pile 

driving of an 18-inch flat-webbed sheet 

pile (which reduced the harassment 

zone sizes and take estimates for gray 

and harbor seals). The Commission 

noted that the thresholds associated 

with slight lung injury and mortality 

were incorrectly specified in the notice 

of the proposed IHA. However, the 

distances to the isopleths for onset of 

and 50 percent probability of 

gastrointestinal tract injury, and the 

resulting estimate of zero take for harbor 

porpoises and phocids, provided 

accurate information regarding the 

potential for this type of non-auditory 

injury. The distances to thresholds 

associated with gastrointestinal injury 

(harbor porpoises, 26 meters (m); 

phocids, 26 m), slight lung injury 

(harbor porpoises, 48 meters; phocids, 

34 m) and mortality (harbor porpoises, 

21 m; phocids, 18 m) calculated for the 

City of Juneau’s Statter Harbor Project 

(see 84 FR 11066; March 25, 2019) are 

similar to each other in magnitude. The 

distances to slight lung injury and 

mortality thresholds are not expected to 

be substantially different for blasting at 

PNSY than those calculated for Statter 

Harbor, and would likely be within tens 

of meters from those estimated here for 

onset of and 50 percent probability of 

gastrointestinal tract injury. All of these 

zones would be smaller than the Level 

A harassment zones for harbor 

porpoises and phocids, and would be 

encompassed by the large shutdown 

zone for blasting at DD1. The mitigation 

requirements for blasting events, 

including the use of stemmed charges, 

installation of a double bubble curtain 

across openings to the super flood basin 

in which blasting will occur, and 

implementation of shutdown 

procedures, are sufficiently protective to 

minimize the potential for non-auditory 

injury such that the potential for nonauditory injury is considered 

discountable. No mortality is 

anticipated or authorized for these 

activities. Per the Commission’s 

recommendations, additional mitigation 

and monitoring requirements for 

blasting have been incorporated into the 

issued authorization. 

The majority of the Commission’s 

comments pertained to errors or 

inconsistencies that have been 

addressed in this notice and the final 

authorization. NMFS’ small numbers 

finding and negligible impact 

determination were not affected by the 

changes from the proposed to the final 

authorization; therefore, NMFS is not 

republishing a notice of the proposed 

authorization. 

Comment 2: The Commission 

recommends that NMFS return the IHA 

application to the Navy as incomplete 

and refrain from processing future 

authorization applications until the 

Commission’s perceived issues are 

resolved. 

Response: NMFS appreciates the 

Commission’s concern but will consider 

any future requests for incidental take 

authorization from the Navy according 

to the requirements of the MMPA. 

Changes From the Proposed IHA to the 

Final IHA 

The following corrections and 

additions have been incorporated into 

this notice and/or the issued IHA: 

• Corrected the reference for the 28- 

inch Z-shaped sheet pile source level 

(NAVFAC 2020; Table 6); 

• Revised source levels for impact 

pile driving of 18-inch flat-webbed sheet 

piles, as well as all associated acoustic 

analyses and take estimation; 

• Included a description of 

transmission loss modeling, as well as 

the coefficients used to estimate Level B 

harassment zones for construction 

activities; 

• Included the input parameters used 

to estimate Level A harassment zones 

for pile driving and removal, and blastcharge hole drilling (Table 8); 

• Corrected distance to the Level B 

harassment isopleth for removal of 30- 

inch steel pipe piles to 13.6 kilometers 

(km) from 46 km (Table 8); 

• Corrected typographical errors 

specifying ensonified zones in Tables 8 

and 9; 

• Included ranges to peak SPL 

thresholds for PTS for blasting events as 

a footnote of Table 9; 

• Refined identification of the 

specific activities to which take is 

attributed (Table 11); 

• Corrected take estimate for harbor 

porpoises (reduced from 6 to 4) to align 

with the IHA application, and adjusted 

take estimates for impact pile driving of 

18-inch flat-webbed sheet piles based on 

revised source levels (Table 11); 

• Added additional mitigation 

requirements for blasting, including (1) 

requiring stemmed charges, (2) 

restricting blasting to a time period at 

least 30 minutes after sunrise and one 

hour before sunset, (3) requiring 

monitoring to occur for at least one hour 

after blasting activities cease, (4) 

requiring that the Navy notify NMFS 

and the Greater Atlantic Regional 

Stranding Coordinator or local stranding 

network at least 24 hours prior to 

commencing a blasting event and within 

24 hours after a blasting event ceases (if 

occurring on consecutive days, the Navy 

can provide notice of how long blasting 

is scheduled to last and when it has 

been completed), and (5) requiring that 

the Navy immediately report any 

injured or dead marine mammal to the 


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Greater Atlantic Regional Stranding 

Coordinator or local stranding network 

and follow any instructions provided by 

the Stranding Coordinator or stranding 

network; 

• Clarified the number and potential 

locations of Protected Species Observers 

(PSOs); 

• Clarified that pile driving/removal 

must only occur during daylight hours; 

• Clarified in this notice that 10, 18- 

inch flat-webbed piles will be 

acoustically monitored during vibratory 

and impact pile driving, and 4, 30-inch 

steel piles will be monitored during 

vibratory pile driving, as was included 

in the draft IHA; 

• Added hydroacoustic monitoring 

plan, which can be accessed at: https:// 

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/incidentaltake-authorizations-constructionactivities#active-authorizations; 

• Corrected contact information and 

requirements for reporting a dead or 

injured marine mammal to provide 

consistency between this notice and the 

IHA; 

• Clarified that the IHA condition 4(e) 

applies to all activities; and 

Description of Marine Mammals in the 

Area of Specified Activities 

Sections 3 and 4 of the application 

summarize available information 

regarding status and trends, distribution 

and habitat preferences, and behavior 

and life history, of the potentially 

affected species. Additional information 

regarding population trends and threats 

may be found in NMFS’ Stock 

Assessment Reports (SARs; https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/marinemammal-stock-assessments) and more 

general information about these species 

(e.g., physical and behavioral 

descriptions) may be found on NMFS’ 

website: (https://

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

Table 2 lists the five marine mammal 

species, including one cetacean and four 

pinnipeds, with the potential to occur in 

the area of the specified activity and for 

which take is authorized for this action, 

and summarizes information related to 

the population or stock, including 

regulatory status under the MMPA and 

ESA and potential biological removal 

(PBR), where known. For taxonomy, 

NMFS follows Committee on Taxonomy 

(2020). PBR is defined by the MMPA as 

the maximum number of animals, not 

including natural mortalities, that may 

be removed from a marine mammal 

stock while allowing that stock to reach 

or maintain its optimum sustainable 

population (as described in NMFS’ 

SARs). While no mortality is anticipated 

or authorized here, PBR and annual 

serious injury and mortality from 

anthropogenic sources are included here 

as gross indicators of the status of the 

species and other threats. 

Marine mammal abundance estimates 

presented in this document represent 

the total number of individuals that 

make up a given stock or the total 

number estimated within a particular 

study or survey area. NMFS’ stock 

abundance estimates for most species 

represent the total estimate of 

individuals within the geographic area, 

if known, that comprises that stock. For 

some species, this geographic area may 

extend beyond U.S. waters. All managed 

stocks in this region are assessed in 

NMFS’ U.S. Atlantic Marine Mammal 

SARs. All values presented in Table 2 

are the most recent available at the time 

of publication and are available in the 

final 2019 SARs (Hayes et al., 2020) and 

draft 2020 SARs, available online at: 

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

national/marine-mammal-protection/ 

draft-marine-mammal-stockassessment-reports). 

TABLE 2—MARINE MAMMALS WITH POTENTIAL PRESENCE WITHIN THE PROJECT AREA

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

strategic 

(Y/N) 1

Stock abundance 

(CV, Nmin, most recent 

abundance survey) 2

PBR Annual 

M/SI 3

Order Cetartiodactyla—Cetacea—Superfamily Odontoceti (toothed whales) 

Family Phocoenidae (porpoises): 

Harbor porpoise .................. Phocoena phocoena ............ Gulf of Maine/Bay of Fundy -; N 95,543 (0.31; 74,034; 2016) ..... 851 217 

Order Carnivora—Superfamily Pinnipedia 

Family Phocidae (earless seals): 

Harbor seal ......................... Phoca vitulina ...................... Western North Atlantic ........ -; N 75,834 (0.15, 66,884; 2012) ..... 2,006 350 

Gray seal ............................ Halichoerus grypus .............. Western North Atlantic ........ -; N 27,131 4 (0.19; 23,158; 2016) ... 1,389 4,729 

Harp seal ............................ Pagophilus groenlandicus ... Western North Atlantic ........ -; N Unknown (NA, NA) ................... unk 232,422 

Hooded seal ....................... Cystophora cristata .............. Western North Atlantic ........ -; N Unknown (NA, NA) ................... unk 1,680 

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

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

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

designated under the MMPA as depleted and as a strategic stock. 2 NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessmentreports-region#reports. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. 3These values, found in NMFS’ SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial fisheries, 

ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated mortality due to commercial fisheries is presented in some cases. 4 NMFS stock abundance estimate applies to U.S. population only, actual stock abundance is approximately 451,431. The PBR value presented is in relation to the 

U.S. population, whereas the annual M/SI value is for the entire stock. 

Detailed descriptions of the species 

likely to be affected by the Navy’s 

activities, including brief introductions 

to the species and relevant stocks as 

well as available information regarding 

population trends and threats, and 

information regarding local occurrence 

were provided in the notice of the 

proposed IHA (86 FR 18244; April 8, 

2021). Since that time, NMFS is not 

aware of any substantive new 

information regarding these species or 

stocks; therefore, detailed descriptions 

are not provided here. Please refer to 

that notice for descriptions. Please also 

refer to NMFS’ website 

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

for generalized species accounts. 

Marine Mammal Hearing 

Hearing is the most important sensory 

modality for marine mammals 

underwater, and exposure to 

anthropogenic sound can have 


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30422 Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 

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. Note that no direct 

measurements of hearing ability have 

been successfully completed for 

mysticetes (i.e., low-frequency 

cetaceans). Subsequently, NMFS (2018) 

described generalized hearing ranges for 

these marine mammal hearing groups. 

Generalized hearing ranges were chosen 

based on the approximately 65 decibel 

(dB) threshold from the normalized 

composite audiograms, with the 

exception for lower limits for lowfrequency cetaceans where the lower 

bound was deemed to be biologically 

implausible and the lower bound from 

Southall et al. (2007) retained. Marine 

mammal hearing groups and their 

associated hearing ranges are provided 

in Table 3. 

TABLE 3—MARINE MAMMAL HEARING GROUPS

[NMFS, 2018] 

Hearing group Generalized hearing 

range * 

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

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

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

australis).

275 Hz to 160 kHz. 

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

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

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

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

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

The pinniped functional hearing 

group was modified from Southall et al. 

(2007) on the basis of data indicating 

that phocid species have consistently 

demonstrated an extended frequency 

range of hearing compared to otariids, 

especially in the higher frequency range 

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

2009; Reichmuth and Holt, 2013). 

For more detail concerning these 

groups and associated frequency ranges, 

please see NMFS (2018) for a review of 

available information. As mentioned 

previously, five marine mammal species 

(one cetacean and four pinniped (all 

phocid) species) have the reasonable 

potential to co-occur with the 

construction activities. Please refer to 

Table 2. The only cetacean species that 

may be present, the harbor porpoise, is 

classified as a high-frequency cetacean. 

Potential Effects of Specified Activities 

on Marine Mammals and Their Habitat 

The effects of underwater noise from 

impact pile driving, vibratory pile 

driving and removal, drilling, and 

blasting activities for the Navy’s 

modification and expansion of DD1 

have the potential to result in Level B 

harassment (behavioral disturbance, 

TTS) for marine mammal species 

authorized for take. Level A harassment 

(injury) in the form of PTS may also 

occur in limited numbers of animals. No 

other forms of Level A harassment 

would occur, nor would serious injury 

or mortality. The project would not 

result in permanent impacts to habitats 

used directly by marine mammals, such 

as haulout sites, but may have potential 

short-term impacts to food sources such 

as forage fish and impacts to the 

substrate during installation and 

removal of piles and as a result of 

bedrock removal. The Federal Register 

notice of the proposed IHA (86 FR 

18244; April 8, 2021) included a 

discussion of the potential effects to 

marine mammals and their associated 

habitat, therefore, that information is 

not repeated here; please refer to the 

notice of proposed IHA for more details. 

Estimated Take 

This section provides an estimate of 

the number of incidental takes 

authorized by the IHA, which informed 

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 be primarily 

by Level B behavioral harassment, as 

noise generated from in-water pile 

driving (vibratory and impact), drilling, 

and blasting has the potential to result 

in disruption of behavioral patterns for 

individual marine mammals. The use of 

the explosive source (i.e., blasting) for a 

very short period each day has the 

potential to result in Temporary 

Threshold Shift (TTS), which is another 

form of Level B harassment. There is 

also some potential for auditory injury 

(Level A harassment) to result from 

impact pile driving and blasting in the 

form of Permanent Threshold Shift 

(PTS). The required mitigation and 

monitoring measures (see Mitigation 

Requirements and Monitoring and 

Reporting Requirements sections) are 

expected to minimize the severity of 

such taking to the extent practicable. 

The primary relevant mitigation 

measure to minimize Level A 

harassment is delaying these activities, 

to the extent practicable, when any 

marine mammal is observed in the Level 

A harassment zones for PTS. While this 

requirement is expected to minimize 

take by Level A harassment, NMFS is 

authorizing takes by Level A harassment 

(in the form of PTS) to account for the 

possibility that marine mammals escape 

observation in the PTS zone and 

because the shutdown zones (see 

Mitigation Requirements section) are, in 

most cases, smaller than the Level A 

harassment zones. The distances to 

thresholds associated with the onset of 

and 50 percent probability of injury to 

the gastrointestinal tract for harbor 

porpoises (5 meters (m)) and phocids (9 


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m) are small enough that the mitigation 

and monitoring measures are expected 

to avoid the potential for such taking. 

As mentioned previously, distances to 

thresholds for slight lung injury and 

mortality are not modeled here, but are 

expected to have a similar small 

magnitude and range of values (tens of 

meters) as those reported for the Statter 

Harbor project (84 FR 11066; March 25, 

2019). In conjunction with small zone 

sizes for onset of and 50 percent 

probability of gastrointestinal tract 

injury and NMFS’ expectation that zone 

sizes for slight lung injury will be small, 

blasting will occur in a confined area 

that allows for effective observation 

with only one entrance to the basin that 

will be blocked by a bubble curtain 

during blasting events, within a large 

shutdown zone equivalent to the Level 

A harassment zone for harbor porpoises, 

all of which make it unlikely that these 

types of non-auditory injuries will 

occur. Therefore, the potential for nonauditory physical injury is considered 

discountable, and any takes by Level A 

harassment are expected to occur due to 

PTS. 

As described previously, no mortality 

is anticipated or authorized for these 

activities. The method by which take is 

estimated is described below. 

Generally speaking, NMFS estimates 

take by considering: (1) Acoustic 

thresholds above which NMFS believes 

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. NMFS notes that while these 

basic 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, 

NMFS describes the factors considered 

here in more detail and presents the 

authorized take. 

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 or experience 

TTS (equated to Level B harassment), or 

to incur PTS of some degree (equated to 

Level A harassment). Thresholds have 

also been developed to identify the 

pressure levels above which animals 

may incur different types of tissue 

damage from exposure to pressure 

waves from explosive detonations. 

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 NMFS considers 

Level B behavioral harassment when 

exposed to underwater anthropogenic 

noise above received levels of 120 dB re 

1 mPa (rms) for continuous (e.g., 

vibratory pile-driving, drilling) and 

above 160 dB re 1 mPa (rms) for 

impulsive and/or intermittent (e.g., 

impact pile driving) sources. 

The Navy’s Portsmouth Naval 

Shipyard modification and expansion 

project includes the use of continuous, 

or non-impulsive, (i.e., vibratory pile 

driving and drilling) and impulsive (i.e., 

impact pile driving) sources; therefore, 

the 120 and 160 dB re 1 mPa (rms) 

thresholds are appropriate. 

Level A harassment for non-explosive 

sources—NMFS’ Technical Guidance 

for Assessing the Effects of 

Anthropogenic Sound on Marine 

Mammal Hearing (Version 2.0) (NMFS, 

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). As noted above, the Navy’s 

planned activity includes the use of 

impulsive and non-impulsive sources. 

These thresholds are provided in 

Table 4. 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 4—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT

Hearing group 

PTS onset acoustic thresholds *

(received level) 

Impulsive Non-impulsive 

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. 

* 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 (HF cetaceans and PW 

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. 

Explosive sources—Based on the best 

available science, NMFS uses the 

acoustic and pressure thresholds 

indicated in Table 5 to predict the onset 

of behavioral harassment, PTS, and nonauditory impacts. Because of the 

instantaneous nature of blasting, there is 

no established Level B behavioral 

harassment threshold associated with 


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the activity. A single detonation is not 

likely to disrupt behavioral patterns 

beyond a brief startle response, 

therefore, the 160 dB re 1 mPa (rms) 

threshold for behavioral harassment 

from impulsive acoustic sources is not 

applicable. However, TTS, which (as 

mentioned previously) is a form of Level 

B harassment take, may occur. The 

behavioral threshold used in analyses 

for multiple explosive events is 

determined relative to (5 dB less than) 

the TTS onset threshold (DoN 2017). 

The threshold associated with the onset 

of effect for non-auditory injury to the 

gastrointestinal tract (237 dB re 1 mPa 

(peak)) is used to determine the 

distances at which there is a one percent 

likelihood of injury occurring, 

informing mitigation measures rather 

than take estimates (DoN 2017). Take 

estimates are based on the 243 dB re 1 

mPa (peak) threshold, the criterion used 

to predict the distances at which there 

is a 50 percent probability of 

gastrointestinal injury resulting from 

underwater explosions (DoN 2017). 

During the public comment period, the 

Marine Mammal Commission noted that 

the thresholds for slight lung injury and 

mortality were incorrectly specified in 

the notice of the proposed IHA. 

However, the distances to isopleths 

associated with the onset of and 50 

percent probability of gastrointestinal 

injury were correctly modeled, resulting 

in very small zone sizes, and the zone 

sizes for slight lung injury and mortality 

(although not presented here) are 

expected to be commensurate with 

those modeled for the City of Juneau’s 

Statter Harbor project (84 FR 11066; 

March 25, 2019), given that both 

projects (1) analyze acoustic impacts of 

confined blasting in drill shafts in 

underwater bedrock within a harbor/ 

basin, (2) utilize the same sound 

exposure level for blasting events, and 

(3) estimate transmission loss by 

combining spherical spreading with 

frequency-specific absorption loss to the 

environment. The size of the shutdown 

zone for blasting, relative to these small 

zones, is sufficiently large to discount 

the potential for this type of injury. The 

shutdown zone for blasting equates to 

the Level A harassment zone for harbor 

porpoises, which is a 0.335 square 

kilometers (km2) arc-shaped area that 

encompasses the super flood basin and 

extends into the Piscataqua River (show 

in Figure 6–5 of the IHA application). 

This shutdown zone fully encompasses 

the Level A harassment zone for 

phocids (0.01978 km2), and onset of 

(0.000254 km2) and 50 percent 

probability of (0.0008 km2) 

gastrointestinal injury zone, Further, the 

Navy will not begin blasting activities 

until one sheet pile face of the west 

closure wall is installed, thus providing 

an additional barrier to sound 

propagating into the environment 

beyond the super flood basin (reducing 

the maximum ensonified zone from 

0.418 km2 to 0.335 km2). In addition, 

the Navy will install a double bubble 

curtain at the entrance to the super 

flood basin during blasting and drilling 

activities within the basin, the 

attenuation from which (although not 

incorporated into the acoustic analyses 

presented here) will further reduce the 

impact of sound produced during these 

activities. The references, analysis, and 

methodology used in the development 

of the thresholds are described in NMFS 

2018 Technical Guidance, which may 

be accessed at: http://

www.nmfs.noaa.gov/pr/acoustics/ 

guidelines.htm. 

TABLE 5—EXPLOSIVE ACOUSTIC AND PRESSURE THRESHOLDS FOR MARINE MAMMALS

Group 

Level B harassment Level A harassment Non-auditory 

Behavioral 

(multiple 

detonations) 

TTS PTS 

Gastro-intestinal 

tract 

(onset of effect) 

Gastro-intestinal 

tract 

(injury) 

High-Frequency (HF) 

Cetaceans.

135 dB SEL ... 140 dB SEL or 196 dB SPLpk 155 dB SEL or 202 dB SPLpk 237 dB SPLpk ... 243 dB SPLpk

Phocid Pinnipeds (PW) 

(Underwater).

165 dB SEL ... 170 dB SEL or 212 dB SPLpk 185 dB SEL or 218 dB SPLpk.

Ensonified Area 

The operational and environmental 

parameters of the activity that fed into 

identifying the area ensonified above 

the acoustic thresholds, which include 

source levels and transmission loss, are 

described below. 

Source Levels 

The project includes impact pile 

driving, vibratory pile driving and pile 

removal, drilling, and blasting. Of these, 

only drilling and vibratory pile driving 

will occur concurrently. When two 

continuous noise sources have 

overlapping sound fields, there is a 

potential for higher sound levels (and a 

larger associated ensonified zone) than 

for non-overlapping sources. When 

drilling and vibratory pile driving cooccur, the larger of the two shutdown 

zones will trigger mitigation measures. 

Source levels of pile driving activities 

are based on reviews of measurements 

of the same or similar types and 

dimensions of piles available in the 

literature. Source levels for impact pile 

driving of a 30-inch steel pipe pile are 

used as a proxy for impact driving of 28- 

inch Z-shaped steel sheet piles 

(NAVFAC, 2020). Similarly, source 

levels for impact pile driving of an 18- 

inch flat-webbed sheet pile were 

unavailable, so proxy values for 

installation of a 24-inch Z-shaped sheet 

pile are used. In the notice of the 

proposed IHA, the proxy source levels 

were incorrectly specified. As a result of 

NMFS’ review of public comment, the 

approach to estimating the source levels 

for this pile type was modified by taking 

the mean of the maximum values for 

each type of sound level in Table 1.6– 

5 of CALTRANS (2015), resulting in the 

decreased source levels shown in Table 

6. 

The source levels in Table 6 are 

assumed for pile driving and drilling 

underwater noise produced by 

construction activities. 


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TABLE 6—SUMMARY OF IN-WATER PILE DRIVING SOURCE LEVELS

[at 10 m from source] 

Pile type Installation/extraction method Pile diameter 

(inch) 

SPLpk, dB 

re 1 μPa 

SPLrms, dB 

re 1 μPa 

SEL, dB 

re 1 μPa2-s 

Z-shaped steel sheet 1 3 .................... Vibratory 2 ......................................... 28 NA 167 167 

Impact 3 ............................................ 28 211 196 181 

Flat-webbed steel sheet 1 4 ............... Vibratory ........................................... 18 NA 163 163 

Impact ............................................... 18 201 183 172 

Steel pipe 2 ........................................ Vibratory ........................................... 30 NA 167 167 

Blast holes 5 ...................................... Drilling .............................................. 4.5 NA 166.2 166.2 

Key: dB = decibels; NA = Not applicable; dB re 1 μPa = dB referenced to a pressure of 1 micropascal, measures underwater SPL. dB re 1 

μPa2-s = dB referenced to a pressure of 1 micropascal squared per second, measures underwater SEL. 

1 = A proxy value for 28-inch sheet piles could not be found for impact and vibratory driving so the proxy for a 30-inch steel pipe pile has been 

used (NAVFAC SW 2020). A proxy value for 18-inch flat-webbed sheet piles could not be found for impact and vibratory driving so the proxy for 

a 24-inch Z-shaped sheet pile has been used (CALTRANS 2015). 

Sources: DoN 2015 2; NAVFAC SW 2020 3 CALTRANS 2015 4; Denes et al., 2016.5

The proxy source level for drilling of 

blast-charge holes is derived from Denes 

et al. (2016), which reports sound 

pressure levels measured during rock 

socket drilling at Kodiak Ferry Terminal 

in Alaska. The size of the blast-charge 

holes considered here (4.5-inch) is 

much smaller than the size of the drilled 

holes (24-inch) in Denes et al. (2016), 

making the use of 166.2 dB re 1mPa 

conservative. 

There are no data on sound source 

levels from explosives used under 

circumstances identical to the blasting 

activity described here (e.g., charge 

composition and weight, bathymetry, 

substrate composition, and the 

dimensions of holes for stemmed charge 

placement). Therefore, the Navy made 

approximations by reference to 

mathematical models that have been 

empirically validated, under roughly 

comparable circumstances, to estimate 

source levels both in terms of absolute 

peak sound pressure level (SPL in units 

of dB re 1mPa) and sound exposure level 

(SEL in units of dB re 1mPa2-s) (Table 7). 

The peak source level calculation of a 

confined blast follows Cole’s (1948) 

equation and a regression curve from 

the Miami Harbor Deepening Project 

(Hempen et al. 2007), using a distance 

of 2.4 m and a weight of 120 pounds 

(lbs) for a single charge. Based on this 

approach, the peak source level for the 

project is estimated to be 257 dB re 1 

mPa for a 120 lb charge. Following Urick 

(1983), the Navy estimated the SEL for 

30, 120 lb charges at 1 m by first 

calculating the instantaneous pressure 

following the onset of a shock wave, as 

a relationship between peak pressure 

and time. Blasting operations will 

involve detonating 120 lb up to 30 times 

in rapid succession, with a split second 

delay between each detonation. Without 

specific information regarding the 

layout of the charges, the modeling 

assumes a grid of 2.4 m by 2.4 m charges 

for the majority of the super flood basin, 

and 1.5 m by 1.8 m for the rows closest 

to Berth 11. Due to time and spatial 

separation of each single charge by a 

distance of 2.4 m, the accumulation of 

acoustic energy is added sequentially, 

assuming the transmission loss follows 

cylindrical spreading within the matrix 

of charges. Using this approach for 

multiple confined charges, the modeled 

source SEL for 30, 120 lb charges at 1 

m is estimated to be 227 dB re 1mPa2- 

s. Please see the Navy’s IHA application 

for more details regarding these 

calculations. 

TABLE 7—BLASTING SOURCE LEVELS

Explosive charge 

SPLpk, 

(dB re 1 

μPa) 

SEL 

(dB re 1 

μPa2-s) 

30 x 120 lb charge 257 227 

These source levels for pile driving, 

drilling, and blasting are used to 

estimate the Level B harassment zones 

and calculate the Level A harassment 

zones. 

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: 

(1) TL = B * log10(R1/R2) 

Where, 

R1 = the distance of the modeled SPL from 

the driven pile, and 

R2 = the distance from the driven pile of the 

initial measurement. 

The degree to which underwater 

sound propagates away from a sound 

source is dependent on a variety of 

factors, most notably the water 

bathymetry and presence or absence of 

reflective or absorptive conditions 

including in-water structures and 

sediments. Spherical spreading occurs 

in a perfectly unobstructed (free-field) 

environment not limited by depth or 

water surface, resulting in a 6 dB 

reduction in sound level for each 

doubling of distance from the source 

(20*log[range]). Cylindrical spreading 

occurs in an environment in which 

sound propagation is bounded by the 

water surface and sea bottom, resulting 

in a reduction of 3 dB in sound level for 

each doubling of distance from the 

source (10*log[range]). A practical 

spreading value of 15 is often used 

under conditions, such as at the 

Shipyard dock, where water increases 

with depth as the receiver moves away 

from the shoreline, resulting in an 

expected propagation environment that 

would lie between spherical and 

cylindrical spreading loss conditions. 

The Level B harassment distances for 

construction activities are calculated 

using practical spreading (impact and 

vibratory pile driving, drilling) and 

spherical spreading with absorption 

(blasting), which includes an additional 

term in the equation that accounts for 

frequency-specific transmission loss to 

the environment due to absorption, 

using the source levels provided in 

Tables 6 and 7, respectively. 

Ensonified areas (A) are calculated 

using the following equation. 

(2) A = pR2

Where, 

R is the harassment distance. 

However, the maximum distance from 

the source is capped due to landmass 

interception in the surrounding area. 

For this reason, the maximum area that 

could be ensonified by noise from pile 

driving and drilling is an estimated 

0.418 km2. Therefore, all harassment 

zones that are larger than 0.418 km2 are 

corrected to this maximum value. The 


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maximum ensonified area for blasting is 

smaller (0.335 km2) because, prior to the 

removal of bedrock, a portion of the 

west closure wall will be installed, 

providing an additional boundary 

between noise produced within the 

super flood basin and the surrounding 

environment. 

Level A Harassment Zones 

When the original NMFS Technical 

Guidance (2016) was published, in 

recognition of the fact that the 

ensonified area/volume could be more 

technically challenging to predict 

because of the duration component in 

the new thresholds, NMFS 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. NMFS notes that because 

of some of the assumptions included in 

the methods used for these tools, NMFS 

anticipates 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 in-water vibratory and 

impact pile driving, NMFS User 

Spreadsheet predicts the closest 

distance at which, if a marine mammal 

remained at that distance the entire 

duration of the activity, it would not 

incur PTS. Inputs used in the User 

Spreadsheet (i.e., pile driving duration 

or number of strikes per pile, and the 

number of piles installed or removed 

per day) used to calculate distances to 

the Level A harassment isopleths for 

pile driving and drilling are shown in 

Table 8. 

For blasting, the calculated distances 

to Level A harassment thresholds are 

based on a single blast event per day. 

The Navy plans to conduct 150 blast 

events over 130 days, so on the majority 

of construction days (110) only one blast 

event will occur. NMFS recognizes that 

if two blasts do occur on a single day, 

the cumulative SEL for the 24-hour 

timeframe over which blasting occurs 

would be higher than that analyzed 

here. However, the distances to the 

Level A harassment thresholds in Table 

9 do not reflect the attenuating 

influence of the double bubble curtain 

that will be in place across any openings 

between the super flood basin and the 

surrounding environment during 

blasting events. If multiple blast events 

occur within a 24-hour period, they will 

be separated by 4 to 5 hours. It is likely 

that if marine mammals are present in 

the vicinity of the construction area 

(outside of the shutdown zone) during 

the first blast event they will avoid the 

area for at least the remainder of day. 

Blasting will occur at multiple 

locations within the super flood basin. 

The minimum and maximum distances 

from the blasting locations to the center 

of the entrance to the super flood basin 

are 37.5 and 160 m, respectively. 

Acoustic modeling is based on the 

location closest to the entrance to the 

basin; the resulting distances to Level B 

harassment and Level A harassment 

isopleths are, therefore, a conservative 

estimate of the maximum extent of 

potential acoustic impact outside of the 

basin. The distance to the Level A 

harassment isopleth for blasting for 

harbor porpoises (1,007 m) is larger than 

that for phocids (110 m), but the density 

of harbor porpoises near the 

construction area is very low (see 

Marine Mammal Occurrence section). 

Harbor seals and gray seals are more 

common, but the distance to the Level 

A harassment isopleth for phocids is 

fully encompassed by the shutdown 

zone. 

The Level A harassment zones are 

calculated using the same Equation (2). 

For all pile driving/drilling activities, 

ensonified areas are based on distances 

to the cumulative SEL Level A 

harassment thresholds using the NMFS 

acoustic guidance (NMFS 2018) because 

they were larger than the values 

calculated against the SPLpeak criteria. 

Following the approach used for 

estimating Level B harassment zones, if 

the calculated value is larger than the 

maximum potential ensonified zone, 

Level A harassment zones are corrected 

to 0.418 km2 for pile driving activity 

and 0.335 km2 for blasting activity. 

The calculated distances to Level A 

harassment and non-auditory injury (to 

the gastrointestinal tract) isopleths, 

estimated distances to Level B 

harassment isopleths, and associated 

ensonified areas for the marine mammal 

species likely to be affected by the 

construction activities are provided in 

Tables 8 and 9. 

TABLE 8—DISTANCES AND AREAS OF HARASSMENT ZONES FOR PILE DRIVING AND DRILLING

Activity Pile size, type, and rate Number of strikes/pile 

or duration 

Number 

of days 

Level A harassment Level B harassment 

HF cetacean Phocid 

Dist. 

(m) 

Area 

(km2 Dist. ) 

(m) 

Area 

(km2) 

Dist. 

(m) 

Area 

(km2) 

Impulsive 

Construct west closure 

wall.

18-inch flat-webbed 

sheet pile (12 pile/ 

day).

300 ............................... 13 516 0.258 232 0.068 341 0.126 

Entrance structure closure walls.28-inch Z-shaped sheet 

pile (12 pile/day).

300 ............................... 4 2,056 0.418 923 0.395 2,512 0.418 

Non-impulsive 

Construct west closure 

wall.

18-inch flat-webbed 

sheet pile (12 pile/ 

day).

5 min/pile 60 min/day ... 13 13.7 0.000556 5.6 0.00098 7,356 0.418 

Install west closure wall 

template.

30-inch steel pipe pile 

(3 pile/day).

5 min/pile 15 min/day ... 5 10.1 0.000319 4.1 0.000053 13,594 0.418 

Remove west closure 

wall template.

30-inch steel pipe pile 

(3 pile/day).

5 min/pile 15 min/day ... 5 10.1 0.000319 4.1 0.000053 13,594 0.418 

Remove temporary dolphins.30-inch steel pipe pile 

(8 pile/day).

5 min/pile 40 min/day ... 2 19.4 0.01068 8.0 0.001996 13,594 0.418 

Entrance structure closure walls.28-inch Z-shaped sheet 

pile (12 pile/day).

5 min/pile 60 min/day ... 4 25.4 0.00174675 10.4 0.000338 13,594 0.418 


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I I I I I I I 
Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 30427 

TABLE 8—DISTANCES AND AREAS OF HARASSMENT ZONES FOR PILE DRIVING AND DRILLING—Continued 

Activity Pile size, type, and rate Number of strikes/pile 

or duration 

Number 

of days 

Level A harassment Level B harassment 

HF cetacean Phocid 

Dist. 

(m) 

Area 

(km2 Dist. ) 

(m) 

Area 

(km2) 

Dist. 

(m) 

Area 

(km2) 

Bedrock drilling for blast 

charges.

4.5-inch (1,580 holes) .. 12 hr/day ...................... 130 7 0.000153 4.3 0.000058 12,023 0.418 

* 0.418 km2 is the maximum ensonified area in the project area for pile driving and drilling due to landmass interception of sound propagation. 

TABLE 9—DISTANCES AND AREAS OF HARASSMENT ZONES FOR BLASTING

Blasting events 

and charge Blasting days 

Level A (PTS onset) harassment 1 Level B (behavioral) harassment Non-auditory injury (gastrointestinal 

tract) 

Harbor porpoise 

distance to 155 

dB SELcum threshold/area of ZOI 

Phocids distance 

to 185 dB SELcum

threshold/area of 

ZOI 

Harbor porpoise 

distance to 135 

dB SELcum threshold/area of ZOI 

Phocids distance 

to 165 dB SELcum

threshold/area of 

ZOI 

Phocid/harbor porpoise distance to 

237 dB peak pressure threshold/ 

area of ZOI 

(onset of effect) 

Phocid/harbor porpoise distance to 

243 dB peak pressure threshold/ 

area of ZOI 

(injury) 

5–30 blasts per 

event, 120-lb 

charge per blast 

event, 150 blast 

events.

130 (1–2 events/ 

day).

1,007 m/0.335 

km2.

110 m/0.01978 

km2.

2,131 m/0.335 

km2.

577 m/0.27636 

km2.

9 m/0.000254 km2 5 m/0.00008 km2

* 0.335 km2 is the maximum ensonified area for blasting in the project area due to landmass interception of sound propagation. 1 Distance to 202 dB SPLpeak threshold for harbor porpoises is 19 m, and to 218 dB SPLpeak threshold for phocids is 3 m. 

Marine Mammal Occurrence 

Marine mammal density estimates for 

the harbor porpoise, harbor seal, and 

gray seal are based on marine mammal 

monitoring observations during 2017 

and 2018 (CIANBRO 2018a, b). Density 

values were calculated from visual 

sightings of all marine mammals 

divided by the monitoring days (total of 

154 days) and the total ensonified area 

in which the sightings occurred in the 

2017 and 2018 activities (0.8401 km2). 

Details used for calculations are 

provided in Table 10 and described 

below. 

TABLE 10—MARINE MAMMAL SIGHTINGS AND RESULTING DENSITY IN THE VICINITY OF PORTSMOUTH NAVAL SHIPYARD

Species 2017 sighting 

(96 days) 

2018 sighting 

(58 days) Total sighting 

Density 

(animal/ 

day/km2) 

Harbor porpoise ........................................................................................... 3 2 5 0.04 

Harbor seal .................................................................................................. 199 122 321 2.48 

Gray seal ..................................................................................................... 24 2 26 0.20 

Hooded and harp seals are much rarer 

than harbor and gray seals in the 

Piscataqua River, and no density 

information for these two species is 

available. To date, marine mammal 

monitoring for the Berth 11 Waterfront 

Improvements Construction project has 

not recorded a sighting of a hooded or 

harp seal in the project area (Cianbro 

2018ab; NAVFAC Mid-Atlantic 2018, 

2019b; Navy 2019; Stantec 2020); 

however, two harp seals were observed 

outside of the timeframe of dedicated 

marine mammal monitoring of Berth 11 

pile-driving activities, one on May 12, 

2020 and one on May 14, 2020 (Stantec 

2020). The Navy requested 

authorization of take for these two 

species, given the potential for 

occurrence, and NMFS is acting on that 

request. 

Take Calculation and Estimation 

The approach by which the 

information provided above is brought 

together to produce a quantitative take 

estimate is described here. 

For marine mammals with calculated 

density information (i.e., harbor 

porpoise, harbor seal, and gray seal), in 

general, estimated Level B harassment 

and Level A harassment take numbers 

are calculated using the following 

equation: 

Estimated take = animal density × 

ensonified area × operating days (3) 

However, in consideration of the 

prevalence of seals in the project area 

and in accordance with the approach 

utilized in IHAs previously issued to the 

Navy for expansion and modification of 

DD1, NMFS has determined that it is 

appropriate to increase the number of 

harbor seal and gray seal Level B 

behavioral harassment takes. Harbor 

seal Level B behavioral harassment 

takes have been adjusted upwards by 

multiplying the average number of 

harbor seals sighted per day from May 

through December 2020 (721 sightings 

divided by 150 days of monitoring, or 5 

harbor seals/day) by the number of 

actual construction days (159), resulting 

in 795 Level B behavioral harassment 

takes. Gray seal Level B harassment 

takes have been increased utilizing the 

same approach (47 sightings divided by 

150 days of monitoring, or 0.31 gray 

seals/day), resulting in 50 Level B 

behavioral harassment takes. 

NMFS authorized one Level B 

harassment take per month for both 

hooded seals and harp seals for the 

Berth 11 Waterfront Improvements 

construction project in both 2018 and 

2019. Following the same approach, the 

Navy has requested, and NMFS has 

authorized, one Level B harassment take 

each of hooded seals and harp seals per 


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30428 Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 

month of construction from January 

through May, when these species may 

occur in the vicinity of DD1 (total of 5 

Level B harassment takes for each 

species). 

The total number of takes authorized 

is presented in Table 11. Non-auditory 

take estimates were zero for all species 

and are, therefore, not included in Table 

11. 

BILLING CODE 3510–22–P 


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EN08JN21.017</GPH>jbell on DSKJLSW7X2PROD with NOTICES

Table 11. Takes Authorized. 

U ndcrwatcr Vibratory Pile-driving and 

Drilling Criteria 

(e.g., non-impulsive/continuous 

sounds) 

Marine 

Mammals Level A Level A LevelB 

(PTS onset) (PTS onset) (Behavioral) 

Harbor porpoise Harbor seal 

Gray seal 

Hooded seal Harp seal 

1 dB re 1 μPa2-s. 

2c!Bre lμPaRMS. 

DDrilling 

8 Blasting 

vvibratory pile-driving 

1 Impact pile-driving 

Threshold 

173 dB 

Harbor 

Porpoise 

0 

NA NA NA NA 

Threshold Harassment 

201 dB Threshold 

Seals 120dB2 RMS 

NA 2D 

0 29V/135D 

0 1v;11n 0 5 

0 5 

Underwater Impact Pile-driving and Blasting Criteria 

(e.g., impulsive sounds) 

LevelB LevelB T

Level A Level A LevelB (Behavioral) 

(PTS onset) (PTS (Behavioral) Hanissment (Behavioral) est

Harassment t

Threshold onset) Harassment Threshold Threshold 155 dB1 185 Threshold 135 dB1 165 dB1 SEL dB 160 dB2 SELcum SELcum Hatbor SEL Seals RMS Hatbor 

Porpoise Porpoise Seals 

2B NA 0 0 NA 

NA 61/63 2 NA 838 NA ]A 0 NA 7A NA 0 0 NA 0 NA 0 0 NA 0 
30430 Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 

BILLING CODE 3510–22–C 

Mitigation Requirements 

In order to issue an IHA under 

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

NMFS must set forth the permissible 

methods of taking pursuant to such 

activity, and other means of effecting 

the least practicable impact on such 

species or stock and its habitat, paying 

particular attention to rookeries, mating 

grounds, and areas of similar 

significance, and on the availability of 

such species or stock for taking for 

certain subsistence uses. 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 such activity or other means 

of effecting the least practicable adverse 

impact upon the affected species or 

stocks and their habitat (50 CFR 

216.104(a)(11)). 

In evaluating how mitigation may or 

may not be appropriate to ensure the 

least practicable adverse impact on 

species or stocks and their habitat, as 

well as subsistence uses where 

applicable, NMFS carefully considers 

two primary factors: 

(1) The manner in which, and the 

degree to which, the successful 

implementation of the measure(s) is 

expected to reduce impacts to marine 

mammals, marine mammal species or 

stocks, and their habitat. This considers 

the nature of the potential adverse 

impact being mitigated (likelihood, 

scope, range). It further considers the 

likelihood that the measure will be 

effective if implemented (probability of 

accomplishing the mitigating result if 

implemented as planned), the 

likelihood of effective implementation 

(probability implemented as planned); 

and 

(2) The practicability of the measures 

for applicant implementation, which 

may consider such things as cost, 

impact on operations, and, in the case 

of a military readiness activity, 

personnel safety, practicality of 

implementation, and impact on the 

effectiveness of the military readiness 

activity. 

In addition to the measures described 

later in this section, the Navy will 

employ the following standard 

mitigation measures: 

• The Navy must employ PSOs, 

establish monitoring locations, and 

monitor the project area to the 

maximum extent possible based on the 

required number of PSOs, required 

monitoring locations, and 

environmental conditions; 

• Monitoring must take place from 30 

minutes prior to initiation of 

construction activities through 30 

minutes post-completion of pile-driving 

and drilling, and 60 minutes postcompletion of blasting events; 

• The Navy must conduct a briefing 

between construction supervisors and 

crews and the marine mammal 

monitoring team prior to the start of 

construction, and when new personnel 

join the work, to explain 

responsibilities, communication 

procedures, marine mammal monitoring 

protocol, and operational procedures; 

• For in-water and over-water heavy 

machinery work, if a marine mammal 

comes within 10 m, operations shall 

cease and vessels shall reduce speed to 

the minimum level required to maintain 

steerage and safe working conditions; 

• With the exception of pre-dawn 

drilling, work must only occur during 

daylight hours, when visual monitoring 

of marine mammals can be conducted; 

• For those marine mammals for 

which take has not been requested, pile 

driving and removal, drilling, and 

blasting will shut down immediately 

when the animals are sighted 

approaching the Level B harassment 

zone; 

• If take reaches the authorized limit 

for an authorized species, activity for 

which take is authorized will be 

stopped as these species approach the 

Level B harassment zone to avoid 

additional take; 

• Blasting will not begin until at least 

one sheet pile face of the west closure 

wall has been installed; 

• Blasting must only occur in good 

visibility conditions between 30 

minutes after sunrise and one hour 

before sunset; 

• Stemming procedures must be used 

for blasting events; and 

• A double bubble curtain will be 

installed across any openings at the 

entrance of DD1 to mitigate underwater 

noise impacts outside of the super flood 

basin during pre-dawn drilling of blastcharge holes and blasting events. 

The following measures will apply to 

the Navy’s mitigation requirements: 

Monitoring Harassment Zones— 

Before the commencement of in-water 

construction activities (i.e., impact pile 

driving, vibratory pile driving and pile 

removal, drilling, and blasting), Level B 

harassment and Level A harassment 

zones must be established for purposes 

of monitoring. Monitoring zones enable 

observers to be aware of and 

communicate the presence of marine 

mammals in the project area outside of 

the shutdown zone (see below) and thus 

prepare for a potential cease of activity 

should the animal enter the shutdown 

zone. All Level B harassment 

monitoring zones for the construction 

activities are equivalent to the 

maximum ensonified zone, adjusted for 

landmass interception, or 0.418 km2. 

Similarly, harassment monitoring zones 

must be established for the PTS 

isopleths associated with each 

functional hearing group. 

Shutdown Zones—The Navy will 

implement shutdown zones for all pile 

driving and removal, drilling, and 

blasting activities. The purpose of a 

shutdown is to prevent some 

undesirable outcome, such as auditory 

injury or severe behavioral disturbance 

of sensitive species, by halting the 

activity. If a marine mammal is observed 

entering or within the respective 

shutdown zone (Table 12) after a 

construction activity has begun, the PSO 

will request a temporary cessation of the 

construction activity. On days when 

multiple activities are occurring 

concurrently, the largest shutdown zone 

between/among the activities will be 

implemented. The shutdown zone for 

blasting will be the entire region of 

influence (ROI), equivalent to the 

maximum ensonified zone adjusted for 

landmass interception (0.335 km2). If 

shutdown zones are obscured by fog or 

poor lighting conditions, pile-driving 

and blasting will not be initiated until 

the entire shutdown zones are visible. 

Although drilling activities may occur 

during pre-dawn hours in order to 

maintain the project schedule, the 

shutdown distance for drilling is small 

(10 m) and will likely be entirely visible 

for monitoring despite visibility 

limitations during this timeframe. As 

mentioned previously, drilling will not 

occur between sunset and pre-dawn 

hours. 

Shutdown zones typically vary based 

on the activity type and marine mammal 

hearing group. A summary of the 

shutdown zones is provided in Table 

12. 


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TABLE 12—SHUTDOWN ZONES DISTANCES FOR CONSTRUCTION ACTIVITIES AND MARINE MAMMAL HEARING GROUPS

Pile type, size & driving method 

Shutdown distance (m) 

HF cetacean Phocid 

Vibratory drive 30-inch steel pipe piles ........................................................................................................................ 70 ................ 30 

Vibratory extraction 30-inch steel pipe piles ................................................................................................................ 70 ................ 30. 

Impact drive 28-inch steel sheet piles .......................................................................................................................... 110 .............. 50. 

Vibratory drive 28-inch steel sheet piles ...................................................................................................................... 25 ................ 10. 

Impact drive 18-inch sheet piles .................................................................................................................................. 110 .............. 50. 

Vibratory drive 18-inch sheet piles ............................................................................................................................... 15 ................ 10. 

Drilling 4.5-inch blast charge holes .............................................................................................................................. 10 ................ 10. 

Blasting 120 lb charge .................................................................................................................................................. Entire ROI 1 Entire ROI. 

1 Region of influence (ROI) for blasting is the maximum ensonified area (0.335 km2). 

Pre-start Clearance Monitoring—Prior 

to the start of daily in-water 

construction activity, or whenever a 

break in pile driving/removal or drilling 

of 30 minutes or longer occurs, PSOs 

will observe the shutdown zones for a 

period of 30 minutes. The shutdown 

zone will be considered cleared when a 

marine mammal has not been observed 

within the zone for that 30-minute 

period. If a marine mammal is observed 

within the shutdown zone, no 

construction activity, including softstart (see below), can proceed until the 

animal has voluntarily left the zone or 

has not been observed for 15 minutes. 

When a marine mammal for which 

Level B harassment take is authorized is 

present in the Level B harassment zone, 

activities may begin. If the entire Level 

B harassment zone is not visible at the 

start of construction, pile driving 

activities can begin. If work ceases for 

more than 30 minutes, the pre-activity 

monitoring of the shutdown zones will 

commence. 

Soft Start—The use of a soft start 

procedure is believed to provide 

additional protection to marine 

mammals by warning marine mammals 

or providing them with a chance to 

leave the area prior to the hammer 

operating at full capacity, and typically 

involves a requirement to initiate sound 

from the hammer at reduced energy 

followed by a waiting period. The Navy 

will provide an initial set of strikes from 

the impact hammer at reduced energy, 

followed by a 30 second waiting period, 

and then two subsequent sets. NMFS 

notes that it is difficult to specify the 

reduction in energy for any given 

hammer because of variation across 

drivers and, for impact hammers, the 

actual number of strikes at reduced 

energy will vary because operating the 

hammer at less than full power results 

in ‘‘bouncing’’ of the hammer as it 

strikes the pile, resulting in multiple 

‘‘strikes’’. Soft start will be implemented 

at the start of each day’s impact pile 

driving and at any time following 

cessation of impact pile driving for a 

period of 30 minutes or longer. 

Based on our evaluation of the 

required measures, NMFS has 

determined that the prescribed 

mitigation measures provide the means 

effecting the least practicable adverse 

impact on the affected species or stocks 

and their habitat, paying particular 

attention to rookeries, mating grounds, 

and areas of similar significance. 

Monitoring and Reporting 

Requirements 

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 action 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; 

• Effects on marine mammal habitat 

(e.g., marine mammal prey species, 

acoustic habitat, or other important 

physical components of marine 

mammal habitat); and 

• Mitigation and monitoring 

effectiveness. 

Monitoring Requirements 

The Navy shall employ trained PSOs 

to conduct marine mammal monitoring 

for its PNSY modification and 

expansion project. The purposes of 

marine mammal monitoring are to 

implement mitigation measures and 

learn more about impacts to marine 

mammals from the Navy’s construction 

activities. 

Protected Species Observer 

Qualifications 

NMFS-approved PSOs shall meet the 

following requirements: 

1. Independent observers (i.e., not 

construction personnel) are required; 

2. At least one observer must have 

prior experience working as an observer; 

3. Other observers may substitute 

education (undergraduate degree in 

biological science or related field) or 

training for experience; 

4. Where a team of three or more 

observers are required, one observer 

should be designated as lead observer or 

monitoring coordinator. The lead 

observer must have prior experience 

working as an observer; and 

5. NMFS will require submission and 

approval of observer curricula vitae 

(CVs). 


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Marine Mammal Monitoring Protocols 

The Navy will monitor all Level B 

harassment zones and Level A 

harassment zones before, during, and 

after construction activities. The Marine 

Mammal Monitoring Plan must include 

the following procedures: 

• At least two (2) PSOs shall be 

posted to monitor marine mammals 

during in-water pile driving and 

removal, drilling, and blasting. 

Additional PSOs will be required in 

conditions of low visibility (i.e., rain or 

light fog), for activities producing the 

largest ensonified zones, and/or if 

marine mammal occurrence is higher 

than expected in the project area; 

• PSOs must be stationed at the best 

possible vantage point(s) in order to 

properly see the entire shutdown 

zone(s) and zones associated with 

behavioral impact thresholds, which 

may include the following locations: 

Berth 2, Berth 12, Isle of Shoals 

Steamship Company, Prescott Park, 

Four Tree Island, Peirce Island, and/or 

a boat or barge within the project limits; 

• PSOs must record all observations 

of marine mammals, regardless of 

distance from the construction activity; 

• During all observation periods, 

PSOs will use high-magnification (25X), 

as well as standard handheld (7X) 

binoculars, and the naked eye to search 

continuously for marine mammals; 

• Monitoring distances will be 

measured with range finders. Distances 

to animals will be based on the best 

estimate of the PSO, relative to known 

distances to objects in the vicinity of the 

PSO; 

• Pile driving and removal, drilling, 

and blasting will only take place when 

the shutdown zones are visible and can 

be adequately monitored. If conditions 

(e.g., fog) prevent the visual detection of 

marine mammals, activities with the 

potential to result in Level A 

harassment shall not be initiated. If such 

conditions arise after the activity has 

begun, blasting and impact pile driving 

or removal will be halted but drilling 

and vibratory pile driving or removal 

will be allowed to continue; 

Information Collection: 

PSOs shall collect the following 

information during marine mammal 

monitoring: 

Æ PSO locations during monitoring; 

Æ Date and time that monitored 

activity begins and ends for each day 

conducted (monitoring period); 

Æ Construction activities occurring 

during each daily observation period, 

including how many and what type of 

piles driven, number of blast holes 

drilled, and number or blast events; 

Æ 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 estimated observable distance; 

Æ For each marine mammal sighting: 

• Name of PSO who sighted the 

animal(s) and PSO location and activity 

at time of sighting; 

• Time of sighting; 

• Species, numbers, and, if possible, 

sex and age class of marine mammals; 

• Description of any observable 

marine mammal behavior patterns, 

including bearing and direction of travel 

and distance from construction activity; 

• Location, distance, and bearing 

from pile driving, drilling, and blasting 

activities to marine mammals and 

distance from the marine mammals to 

the observation point; 

• Animal’s closet point of approach 

and estimated amount of time that the 

animals remained in the Level B 

harassment and Level A harassment 

zones; and 

• Detailed information about 

implementation of any mitigation (e.g., 

shutdowns or delays), a description of 

specific actions that ensued, and 

resulting changes in behavior of the 

animal(s), if any. 

• Percentage of time that activities 

(i.e., drilling) occur at night. 

Hydroacoustic Monitoring 

The Navy must conduct 

hydroacoustic monitoring of in-water 

construction activities, including the 

installation of (10) 28-inch Z-shaped 

sheet piles and (10) 18-inch flat-webbed 

sheet piles for both impact and vibratory 

pile driving, (4) 30-inch steel piles for 

vibratory pile driving, (10) 120 lbs 

blasting events, and (10) 4.5-inch blastcharge hole drilling events. Near-field 

monitoring will occur at 10 m from the 

pile driving hammers and drilling 

location. During blasting, near-field data 

will be collected using a pressure 

transducer to estimate sounds levels 

based on received impulse. The far-field 

hydrophone will be placed as far from 

the acoustic source as is practicable, 

although the distance will limited by 

DD1’s proximity to a navigable channel 

outside of the entrance to the super 

flood basin. Monitoring will only be 

conducted when concurrent activities 

are not occurring, limiting interference 

in the recordings from other sources of 

noise in the environment. 

Reporting Requirements 

The Navy is required to submit a draft 

monitoring report (including all PSO 

data sheets and/or raw sighting data) 

within 90 days after completion of the 

construction work or the expiration of 

the IHA, whichever comes earlier. This 

report must detail the monitoring 

protocol, summarize the data recorded 

during monitoring, and estimate the 

number of marine mammals that may 

have been harassed. The draft 

hydroacoustic monitoring report must 

be submitted within the same timeframe 

and must contain the informational 

elements described in the hydroacoustic 

monitoring plan for all acoustically 

monitored events, including: A 

description of the hydrophones used, 

hydrophone locations (both near- and 

far-field) and water depths, recording 

device(s), distance from the acoustic 

source, and sediment type at the 

recording location; type and size of pile 

being driven, method of pile-driving 

during recording (hammer model and 

energy), and total driving/removal or 

drilling duration. For impact pile 

driving, the Navy must also report: 

Number of strikes and strike rate, depth 

of substrate penetrated, pulse duration, 

and mean, median, and maximum 

sound levels (db re 1 m Pa) (root mean 

square sound pressure level (SPLrms); 

cumulative sound exposure level 

(SELcum), peak sound pressure level 

(SPLpeak), and single-strike sound 

exposure level (SELs-s)). For vibratory 

pile driving or removal and drilling, the 

Navy must also report: Median, 

minimum and maximum sound levels 

(db re 1 m Pa) (SPLrms, SELcum), and 

the timeframe over which the sound is 

averaged. For blast events, the Navy 

must also report: Number of blast events 

per day, time between blast events if 

two are conducted within a 24-hour 

period, total number of charges/delays, 

maximum net explosive weight (NEW) 

of a single charge and the total NEW of 

the event, timeframe between delays 

and total timeframe of event, impulse in 

Pa-sec, SPLpeak for each event and 

SELcum values for the entire 24 hours 

over which blasting occurs. For all 

activities, reported SPLrms values must 

be based on a time window that consists 

of 90 percent of the acoustic energy. 

Power spectral density plots and onethird octave band spectra must be 

provided for all acoustically monitored 

construction activities. If, for any 

reason, the total number of events 

included in the hydroacoustic 

monitoring plan are not monitored 

within the overall construction 

timeframe, the Navy must report the 

actual number of events monitored. 

NMFS will have an opportunity to 

provide comments on the report and, if 

NMFS has comments, the Navy will 

address the comments and submit a 

final report to NMFS within 30 days. 


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The Navy is required to notify NMFS’ 

Office of Protected Resources (OPR) and 

NMFS’ Greater Atlantic Regional 

Stranding Coordinator or local stranding 

network at least 24 hours prior to 

commencing blasting events as well as 

within 24 hours after blasting events 

cease. If blasting events occur on 

consecutive days, the Navy must 

communicate how long the blasting is 

scheduled to last as well as when it is 

completed. In addition, in the event that 

personnel involved in the construction 

activities discover an injured or dead 

marine mammal, the Navy must 

immediately report the incident to 

NMFS OPR and the Stranding 

Coordinator or local stranding network 

and follow any instructions provided by 

the Stranding Coordinator or stranding 

network. If the death or injury was 

clearly caused by the specific activity, 

the Navy must immediately cease the 

specified activities until NMFS OPR is 

able to review the circumstances of the 

incident and determine what, if any, 

additional measures are appropriate to 

ensure compliance with the terms of the 

IHA. The Navy must not resume their 

activities until notified by NMFS OPR. 

The Navy shall provide NMFS OPR and 

the Stranding Coordinator or local 

stranding network with the species or 

description of the animal(s), the 

condition of the animal(s) (including 

carcass condition, if the animal is dead), 

location, time of first discovery, 

observed behaviors (if alive), and photo 

or video (if available). 

In the event that the Navy finds an 

injured or dead marine mammal that is 

not in the construction area, the Navy 

would report the same information as 

listed above to the Stranding 

Coordinator or local stranding network 

and NMFS OPR as soon as is 

operationally feasible. 

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. NMFS also assesses 

the number, intensity, and context of 

estimated takes by evaluating this 

information relative to population 

status. Consistent with the 1989 

preamble for NMFS’ implementing 

regulations (54 FR 40338; September 29, 

1989), the impacts from other past and 

ongoing anthropogenic activities are 

incorporated into this analysis via their 

impacts on the 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). 

Pile driving and removal, drilling, and 

blasting activities associated with the 

project, as described previously, have 

the potential to disturb or temporarily 

displace marine mammals. The 

specified activities may result in take, in 

the form of Level A harassment 

(potential injury; from impact pile 

driving or blasting) or Level B 

harassment (potential behavioral 

disturbance or TTS) from underwater 

sounds generated from pile driving 

(impact and vibratory), drilling and 

blasting. Potential takes could occur if 

individual marine mammals are present 

in the ensonified zone when pile 

driving, drilling, or blasting activities 

are occurring. 

To avoid repetition, this introductory 

discussion of NMFS’ analysis applies to 

all of the species listed in Table 2, given 

that the anticipated effects of the Navy’s 

PNSY modification and expansion 

construction project activities on marine 

mammals are expected to be relatively 

similar in nature. There is no 

information about the nature or severity 

of the impacts, or the size, status, or 

structure of any species or stock that 

would lead to a different analysis by 

species for this activity, or else speciesspecific factors would be identified and 

analyzed. 

Although some individual harbor 

porpoises and harbor and gray seals are 

estimated to experience Level A 

harassment in the form of PTS if they 

remain within the impact pile driving 

Level A harassment zone for an entire 

day, or are present within the Level A 

harassment zone during a blasting 

event, the degree of injury is expected 

to be mild and is not likely to affect the 

reproduction or survival of the 

individual animals. It is expected that, 

if hearing impairments occurs as a result 

of impact pile driving or blasting, the 

affected animal would lose a few dB in 

its hearing sensitivity, which in most 

cases is not likely to affect its survival 

and recruitment. Hearing impairment 

that might occur for these individual 

animals would be limited to the 

dominant frequency of the noise 

sources, (i.e., in the low-frequency 

region below 2 kHz). Nevertheless, as 

for all marine mammal species, it is 

anticipated that, in general, these 

pinnipeds will avoid areas where sound 

levels could cause hearing impairment. 

Therefore, it is not likely that an animal 

would stay in an area with intense noise 

that could cause severe levels of hearing 

damage. 

Under the majority of the 

circumstances, anticipated takes are 

expected to be limited to short-term 

Level B behavioral harassment or TTS. 

Marine mammals present in the vicinity 

of the action area and taken by Level B 

harassment would most likely show 

overt brief disturbance (startle reaction) 

from blasting events and avoidance of 

the area impacted by elevated noise 

levels during pile driving (and removal) 

and drilling. Given the limited 

estimated number of predicted incidents 

of Level B harassment and Level A 

harassment and the limited, short-term 

nature of the responses by the 

individuals, the impacts of the 

estimated take cannot be reasonably 

expected to, and are not reasonably 

likely to, rise to the level that they 

would adversely affect the species 

considered here at the population level, 

through effects on annual rates of 

recruitment or survival. There are no 

known important habitats, such as 

rookeries or haulouts, in the vicinity of 

the Navy’s PNSY DD1 modification and 

expansion construction project. The 

project also is not expected to have 

significant adverse effects on affected 

marine mammals’ habitat, including 

prey, as analyzed in detail in the 

Potential Effects of Specified Activities 

on Marine Mammals and their Habitat 

section in the Federal Register notice 

for the proposed IHA (86 FR 18244; 

April 8, 2021). 

In summary and as described above, 

the following factors primarily support 

our determination that the impacts 

resulting from this activity are not 

expected to adversely affect the species 

or stock through effects on annual rates 

of recruitment or survival: 

• No mortality is anticipated or 

authorized; 

• Some individual marine mammals 

might experience a mild level of PTS, 

but the degree of PTS is not expected to 

affect their survival; 

• Most adverse effects to marine 

mammals are likely to be temporary 

behavioral harassment or TTS; and 


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30434 Federal Register / Vol. 86, No. 108 / Tuesday, June 8, 2021 / Notices 

• No biologically important area is 

present in or near the construction area. 

Based on the analysis contained 

herein of the likely effects of the 

specified activity on marine mammals 

and their habitat, and taking into 

consideration the implementation of the 

monitoring and mitigation measures, 

NMFS finds that the total marine 

mammal take from the 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 section 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, 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 less 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. 

NMFS authorizes incidental take of 5 

marine mammal stocks. The total 

amount of take authorized is three 

percent or less for all five of these stocks 

(Table 11). 

Based on the analysis contained 

herein of the activity (including the 

prescribed mitigation and monitoring 

measures) and the anticipated take of 

marine mammals, NMFS finds that 

small numbers of marine mammals will 

be taken relative to the population size 

of the affected species or stocks. 

Unmitigable Adverse Impact Analysis 

and Determination 

There are no relevant subsistence uses 

of the affected marine mammal stocks or 

species implicated by this action. 

Therefore, NMFS has determined that 

the total taking of affected species or 

stocks would not have an unmitigable 

adverse impact on the availability of 

such species or stocks for taking for 

subsistence purposes. 

Endangered Species Act (ESA) 

No incidental take of ESA-listed 

species is authorized or expected to 

result from this activity. Therefore, 

NMFS has determined that formal 

consultation under section 7 of the ESA 

is not required for this action. 

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. 

This action is consistent with 

categories of activities identified in 

Categorical Exclusion B4 (IHA with no 

anticipated serious injury or mortality) 

of the Companion Manual for NOAA 

Administrative Order 216–6A, which do 

not individually or cumulatively have 

the potential for significant impacts on 

the quality of the human environment 

and for which NMFS has not identified 

any extraordinary circumstances that 

would preclude this categorical 

exclusion. Accordingly, NMFS has 

determined that the issuance of the IHA 

qualifies to be categorically excluded 

from further NEPA review. 

Authorization 

As a result of these determinations, 

NMFS has issued an IHA to the Navy for 

the taking of marine mammals 

incidental to modification and 

expansion of the Portsmouth Naval 

Shipyard Dry Dock 1 in Kittery, Maine, 

effective for one year from the date of 

issuance, provided the previously 

mentioned mitigation, monitoring, and 

reporting requirements are incorporated. 

A copy of the final IHA can be found at 

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

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

Dated: June 3, 2021. 

Catherine Marzin, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2021–11983 Filed 6–7–21; 8:45 am] 

BILLING CODE 3510–22–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XB131] 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to Site 

Characterization Surveys Off the Coast 

of Massachusetts; Correction 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; modified proposal of an 

incidental harassment authorization; 

request for comments on modified 

proposed authorization and possible 

renewal; correction. 

SUMMARY: This document contains 

corrections to the DATES section of the 

notice of modified proposed incidental 

harassment authorization (IHA) for take 

of marine mammals incidental to 

marine site characterization surveys in 

coastal waters of Massachusetts 

published in the Federal Register on 

May 20, 2021. This action is necessary 

to notify the public of the end date of 

the public comment period, which was 

inadvertently omitted from the notice. 

This document corrects that omission; 

all other information is unchanged. 

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. 

SUPPLEMENTARY INFORMATION: 

Background 

NMFS published a notice of a 

modified proposed IHA in the Federal 

Register on May 20, 2021 (86 FR 27393), 

based on a request from Mayflower 

Wind Energy LLC (Mayflower) for 

authorization to take marine mammals 

incidental to site characterization 

surveys off the coast of Massachusetts in 

the area of the Commercial Lease of 

Submerged Lands for Renewable Energy 

Development on the Outer Continental 

Shelf (OCS–A 0521) and along potential 

submarine cable routes to landfall 

locations at Falmouth, Massachusetts 

and near Narragansett Bay. The 

information in the notice of modified 

proposed IHA is not repeated here. As 

published, the notice of modified 

proposed IHA (86 FR 27393; May 20, 


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