Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Washington State Department of Transportation Purdy Bridge Rehabilitation Project, Pierce County, WA, 8598-8608 [2021-02489]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 86, Number 24 (Monday, February 8, 2021)]
[Notices]
[Pages 8598-8608]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-02489]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA829]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Washington State Department of 
Transportation Purdy Bridge Rehabilitation Project, Pierce County, WA

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the

[[Page 8599]]

Washington State Department of Transportation (WADOT) to incidentally 
harass, by Level B harassment only, marine mammals during construction 
activities associated with a Purdy Bridge Rehabilitation Project in 
Pierce County, WA.

DATES: This Authorization is effective from July 16, 2021 through 
February 15, 2022.

FOR FURTHER INFORMATION CONTACT: Dwayne Meadows, Ph.D., Office of 
Protected Resources, NMFS, (301) 427-8401. Electronic copies of the 
application and supporting documents, as well as a list of the 
references cited in this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

Summary of Request

    On July 27, 2020, NMFS received an application from WADOT 
requesting an IHA to take small numbers of six species of marine 
mammals incidental to pile driving and removal associated with the 
Purdy Bridge Rehabilitation Project. The application was deemed 
adequate and complete on December 1, 2020. WADOT's request is for take 
of a small number of each species by Level B harassment. Neither WADOT 
nor NMFS expects serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.

Description of Specified Activity

Overview

    The purpose of the project is to rehabilitate the 2 in-water 
support piers of the State Route 302 Purdy Bridge by removing the top 3 
inches (7.5 centimeter (cm)) of decaying concrete on each support pier 
and replacing with fiberglass reinforced concrete. Twenty steel H piles 
and 44 sheetpiles will be driven to create a caisson-like dewatered 
structures around the bridge piers to allow the work to be completed. 
Once the work on the piers is completed the piles will be removed. A 
needle gun will be used to remove 3 inches (7.5 cm) of decayed concrete 
from the two in-water bridge piers. Pile driving/removal and concrete 
removal is expected to take no more than 20 days. Pile driving/removal 
would be by vibratory pile driving. A detailed description of the 
planned project is provided in the Federal Register notice for the 
proposed IHA (85 FR 81886; December 17, 2020). Since that time, no 
changes have been made to the planned activities. Therefore, a detailed 
description is not provided here. Please refer to that Federal Register 
notice for the description of the specific activity.

Comments and Response

    A notice of NMFS's proposal to issue an IHA to WADOT was published 
in the Federal Register on December 17, 2020 (85 FR 81886). That notice 
described, in detail, WADOT'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 no 
public comment or comment letter from the Marine Mammal Commission.

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's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS's 
website (https://www.fisheries.noaa.gov/find-species).
    Table 1 lists all species with expected potential for occurrence in 
the project area and summarizes information related to the population 
or stock, including regulatory status under the MMPA and Endangered 
Species Act (ESA) and potential biological removal (PBR), where known. 
For taxonomy, we follow 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's 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's 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's U.S. Pacific or Alaska SARs (e.g., Caretta et al., 2020; Muto et 
al., 2020).

[[Page 8600]]



                    Table 1--Species That Spatially Co-Occur With the Activity to the Degree That Take Is Reasonably Likely To Occur
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/MMPA status;    Stock abundance  (CV,
             Common name                  Scientific name               Stock            strategic  (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern North Pacific..  -, -, N             26,960 (0.05, 25,849,         801        138
                                                                                                             2016).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Short-beaked Common Dolphin.....  Delphinus delphis......  California/Oregon/       -, -, N             969,861 (0.17,               8393        >40
                                                                Washington.                                  839,325, 2014).
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Washington Inland        -, -, N             11,233 (0.37, 8,308,           66      >=7.2
                                                                Waters.                                      2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    California Sea Lion.............  Zalophus californianus.  United States..........  -, -, N             257,606 (N/A, 233,515,     14,011       >321
                                                                                                             2014).
    Steller Sea Lion................  Eumetopias jubatus.....  Eastern DPS............  -, -, N             43,201 a (see SAR,           2592        112
                                                                                                             43,201, 2017).
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  Southern Puget Sound...  -, -, N             UNK (UNK, UNK, 1999)..        UND        3.4
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered 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-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. UNK -Unknown, UND--Undetermined.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual Mortality/Serious Injury (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.

    Harbor seal, California sea lion, and Harbor porpoise spatially co-
occur with the activity to the degree that take is reasonably likely to 
occur, and we have authorized it. For gray whale, Steller sea lion, and 
short-beaked common dolphin, occurrence is such that take is possible, 
and we have authorized it.
    Transient killer whales (Orcinus orca) spatially co-occur with the 
activity to the degree that take is possible, while Southern Resident 
killer whales and humpback whales (Megaptera novaeangliae) are very 
rare visitors to the area. Work will be shutdown if any of these 
species approach the Level B harassment zone, so take is not requested 
for these species and they are not further discussed. A detailed 
description of the species likely to be affected by the project, 
including brief introductions to the species and relevant stocks as 
well as available information regarding population trends and threats, 
and information regarding local occurrence, were provided in the 
Federal Register notice for the proposed IHA (85 FR 81886; December 17, 
2020); since that time, we are not aware of any changes in the status 
of these species and stocks; therefore, detailed descriptions are not 
provided here. Please refer to that Federal Register notice for these 
descriptions. Please also refer to NMFS' website (https://www.fisheries.noaa.gov/find-species) for generalized species accounts.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    The effects of underwater noise from WADOT's construction 
activities have the potential to result in behavioral harassment of 
marine mammals in the vicinity of the survey area. The notice of 
proposed IHA (85 FR 81886; December 17, 2020) included a discussion of 
the effects of anthropogenic noise on marine mammals and the potential 
effects of underwater noise from the WADOT's construction activities on 
marine mammals and their habitat. That information and analysis is 
incorporated by reference into this final IHA determination and is not 
repeated here; please refer to the notice of proposed IHA (85 FR 81886; 
December 17, 2020).

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorized through this IHA, which will inform both NMFS' consideration 
of ``small numbers'' and the negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance, which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment, as use of the 
acoustic source (i.e., vibratory pile driving/removal and needle gun) 
has the potential to result in disruption of behavioral patterns for 
individual marine mammals. Based on the nature of the activity and the 
anticipated effectiveness of the mitigation measures (i.e., shutdown)--
discussed in detail below in Mitigation section, Level A harassment is 
not authorized.
    As described previously, no mortality is authorized for this 
activity. Below we describe how the take is estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed

[[Page 8601]]

or incur some degree of permanent hearing impairment; (2) the area or 
volume of water that will be ensonified above these levels in a day; 
(3) the density or occurrence of marine mammals within these ensonified 
areas; and, (4) and the number of days of activities. We note that 
while these 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, we describe 
the factors considered here in more detail and present the take 
estimate.
    The effect of needle guns is unclear as we have not recently 
authorized take by this method in these circumstances. Given the 
relatively low source level for needle guns and small ensonified areas 
discussed below, there is some uncertainty about whether take will 
occur from this activity. However, in consideration of the applicant's 
request and the predicted source levels, we conservatively authorize 
some take for this project.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur Permanent Threshold Shift (PTS) of some 
degree (equated to Level A harassment). Thresholds have also been 
developed identifying the received level of in-air sound above which 
exposed pinnipeds would likely be behaviorally harassed.
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 decibel (dB) re 1 microPascal ([mu]Pa) (root 
mean square (rms)) for continuous (e.g., vibratory pile-driving) and 
above 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive (e.g., 
impact pile driving) or intermittent (e.g., scientific sonar) sources. 
For in-air sounds, NMFS predicts that harbor seals exposed above 
received levels of 90 dB re 20 [mu]Pa (rms) will be behaviorally 
harassed, and other pinnipeds will be harassed when exposed above 100 
dB re 20 [mu]Pa (rms).
    WADOT's proposed activity includes the use of continuous (vibratory 
pile-driving and removal in water and needle guns in air) sources, and 
therefore the 120 dB re 1 [mu]Pa (rms) threshold is applicable in water 
and the pinniped thresholds are applicable in air.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). WADOT's activity includes the use of non-
impulsive (vibratory pile driving/removal) sources.
    These thresholds are provided in Table 2. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS 2018 Technical Guidance, which may be accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

 Table 2--Thresholds Identifying the Onset of Permanent Threshold Shift
------------------------------------------------------------------------
                                                   PTS onset acoustic
                                                  thresholds (received
                Hearing group                            level)
                                              --------------------------
                                                     Non-impulsive
------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans.................  Cell 2: LE,LF,24h: 199
                                                dB.
Mid-Frequency (MF) Cetaceans.................  Cell 4: LE,MF,24h: 198
                                                dB.
High-Frequency (HF) Cetaceans................  Cell 6: LE,HF,24h: 173
                                                dB.
Phocid Pinnipeds (PW) (Underwater)...........  Cell 8: LE,PW,24h: 201
                                                dB.
Otariid Pinnipeds (OW) (Underwater)..........  Cell 10: LE,OW,24h: 219
                                                dB.
------------------------------------------------------------------------
Note: Cumulative sound exposure level (LE) has a reference value of
  1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect
  American National Standards Institute standards (ANSI 2013). The
  subscript associated with cumulative sound exposure level thresholds
  indicates the designated marine mammal auditory weighting function
  (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the
  recommended accumulation period is 24 hours. The cumulative sound
  exposure level thresholds could be exceeded in a multitude of ways
  (i.e., varying exposure levels and durations, duty cycle). When
  possible, it is valuable for action proponents to indicate the
  conditions under which these acoustic thresholds will be exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., vibratory pile driving and 
removal and needle guns).
    Vibratory hammers produce constant sound when operating, and 
produce vibrations that liquefy the sediment surrounding the pile, 
allowing it to penetrate to the required seating depth. The actual 
durations of each installation method vary depending on the type and 
size of the pile.
    In order to calculate distances to the Level A harassment and Level 
B harassment sound thresholds for activities being used in this 
project, NMFS used acoustic monitoring data from other locations to 
develop source levels or the various pile types, sizes and methods (see 
Table 3). Source levels for the 48-inch sheetpiles come from the

[[Page 8602]]

Caltrans compendium (2015) measurements of 24-inch steel sheetpiles 
supported by acoustic data from another project in Seattle, Washington 
that used 48-inch steel sheetpiles (Greenbusch Group, 2015), while the 
source data for H piles comes from the Caltrans (2015) compendium. 
Needle guns can produce sounds up to 112 dbA (OSHA, 2020) and we use 
that as the source level for that activity.

                                      Table 3--Project Sound Source Levels
----------------------------------------------------------------------------------------------------------------
             Method                         Pile type               Estimated noise level           Source
----------------------------------------------------------------------------------------------------------------
Vibratory Driving/Removal.......  48-inch sheet...............  165 dBRMS...................  CALTRANS 2015,
                                                                                               Greenbusch Group
                                                                                               2015.
Vibratory Driving/Removal.......  12-inch H pile..............  150 dBRMS...................  CALTRANS 2015.
----------------------------------------------------------------------------------------------------------------
Note: SEL = single strike sound exposure level; dB peak = peak sound level; rms = root mean square.

Level B Harassment Zones

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2)

where,

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement.

    The recommended TL coefficient for most nearshore environments is 
the practical spreading value of 15. This value results in an expected 
propagation environment that would lie between spherical and 
cylindrical spreading loss conditions, which is the most appropriate 
assumption for WADOT's proposed activity in the absence of specific 
modelling.
    Using the equation above, underwater noise is predicted to fall 
below the behavioral effects threshold of 120 dB rms for marine mammals 
at distances of 1,000 or 10,000 m depending on the pile type(s) and 
methods (Table 4). It should be noted that based on the geography of 
Henderson Bay, sound will not reach the full distance of the Level B 
harassment isopleths in most directions. In-air needle gun noise is 
predicted to reach the phocid (harbor seal) threshold (90 dB) at 192 
meters (629 feet), and the otariid threshold (100 dB) at 60 meters (200 
feet).

                               Table 4--Level A and Level B Harassment Isopleths (m) for Each Pile Type and Hearing Group
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Level A harassment
                        Pile type                        --------------------------------------------------------------------------------     Level B
                                                           Low frequency   Mid frequency  High frequency      Otariid         Phocid        harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sheet...................................................            31.8             2.8              47            19.3             1.4          10,000
H pile..................................................             3.2             0.3             4.7             1.9             0.1           1,000
--------------------------------------------------------------------------------------------------------------------------------------------------------

Level A Harassment Zones

    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of take by Level A harassment. 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 
vibratory pile driving or removal using any of the methods discussed 
above, NMFS User Spreadsheet predicts the closest distance at which, if 
a marine mammal remained at that distance the whole duration of the 
activity, it would not incur PTS. Inputs used in the User Spreadsheet 
are reported in Table 5 and the resulting isopleths are reported in 
Table 4 for each of the work scenarios. Note that while the inputs for 
driving and removal of each type of pile are different, the resulting 
isopleths are the same because the total time per day (number of piles 
per day times minutes per pile) of pile driving is identical. Therefore 
Table 4 includes only a single row for each pile type. The above input 
scenarios lead to PTS isopleth distances (Level A thresholds) of less 
than 1 m to 47 m.
    The Level A harassment zones identified in Table 4 are based upon 
an animal exposed to pile driving multiple piles per day. Considering 
duration of driving or removing each pile (up to 30 minutes) and breaks 
between pile installations (to reset equipment and move pile into 
place), this means an animal would have to remain within the small area 
estimated to be ensonified above the Level A harassment threshold for 
multiple hours. This is highly unlikely given marine mammal movement 
throughout the area.

[[Page 8603]]



Table 5--NMFS Technical Guidance User Spreadsheet Input To Calculate Level A Isopleths for a Combination of Pile
                                                     Driving
----------------------------------------------------------------------------------------------------------------
                                                                   Source level     Minutes per
               Method                          Pile type             (db RMS)          pile        Piles per day
----------------------------------------------------------------------------------------------------------------
Vibratory Driving...................  Sheet.....................             165              30               8
Vibratory Driving...................  H pile....................             150              30               8
Vibratory Removal...................  Sheet.....................             165              15              16
Vibratory Removal...................  H pile....................             150              15              16
----------------------------------------------------------------------------------------------------------------
Note: Transmission Loss for all methods is 15 LogR and the weighting factor adjustment is 2.5.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. The main source of density information for the area is 
the U.S. Navy's database used to establish baseline density estimates 
for their construction and testing and training activities in Puget 
Sound (U.S. Navy, 2019). The Navy database includes seasonal estimates 
of abundance where available and appropriate. Where such estimates 
existed, we used the larger density estimate for the fall or summer 
seasons, when this project is scheduled to occur. These density 
estimates are shown in Table 6. No density estimates exist for the 
rarer short-beaked common dolphin so we used more qualitative data on 
observations from The Whale Museum's sightings database and project 
specific report to WADOT (TWM, 2020).

   Table 6--Density of Marine Mammals Used To Calculate Expected Take
------------------------------------------------------------------------
                                                               Density #/
                           Species                               km\2\
------------------------------------------------------------------------
Harbor seal..................................................       3.91
California sea lion..........................................     0.2211
Steller sea lion.............................................     0.0478
Gray whale...................................................   0.000086
Short-beaked common dolphin..................................        (*)
Harbor porpoise..............................................       0.86
------------------------------------------------------------------------
* See text, no density estimate exists for short-beaked common dolphins.

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate. Given the geography 
of the project area, the area ensonified when driving or removing H 
piles is 1.36 square kilometers (km\2\) 0.53 square miles (mi\2\)), the 
area ensonified when driving or removing sheetpiles is 17.9 km\2\ (6.9 
mi\2\), and the area ensonified when using the needle gun is 0.06 km\2\ 
(0.023 mi\2\) for phocids and 0.01 km\2\ (0.004 mi\2\) for otariids. As 
noted above, there will be a total of 5 days driving or removing H 
piles, 9 days driving or removing sheetpiles, and 6 days of using the 
needle gun. For species with density estimates, the estimated take is 
calculated as the sum of the density times the area and days for each 
pile type/activity with the results for each activity added to give a 
total estimated take. Additional qualitative factors may be considered 
for species with small estimated take calculations (see below). Take by 
Level B harassment is authorized and summarized in Table 7.

Gray Whale

    The Navy Marine Species Density Database (U.S. Navy 2019) estimates 
the density of gray whales in the Henderson Bay area as 0.000086/km\2\. 
Based on this density estimate, the following number of gray whales may 
be present in the Level B harassment zones:

H piles: 0.000086/km\2\ * 1.36 km\2\ * 5 days = 0.0005848
Sheetpiles: 0.000086/km\2\ * 17.9 km\2\ * 9 days = 0.0138546
Total Estimated Take = 0.014 animals

    The total represents less than one gray whale. In the event an 
individual enters the area and remains for some time and is harassed on 
multiple days, we are authorizing Level B harassment of 10 gray whales. 
Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
gray whales.

Short-Beaked Common Dolphin

    As mentioned above, the Navy Marine Species Density Database (U.S. 
Navy 2019) does not provide an estimate of density of short-beaked 
common dolphins in the Henderson Bay area. The Whale Museum data 
indicate that common dolphins have been documented in waters adjacent 
to the project (TWM, 2020). Nearly all sightings were in 2016 and 2017 
pointing out the variability and uncertainty of their presence. Short-
beaked common dolphins often occur in groups; for the Puget Sound data 
groups consisted of no more than five individuals (Orca Network. 2020). 
Due to the low likelihood of occurrence an expectation of one group of 
five animals in the large level B harassment zone for sheetpiles per 
day is a reasonable representation of occurrence. With 9 days of 
sheetpiling maximum this equates to 45 level B takes. Because of the 
smaller size of the Level B harassment zones for the H piles, we expect 
that one group of five animals over the course of the 5 work days with 
H piles is a reasonable representation of occurrence. We are thus 
authorizing Level B harassment of 50 short-beaked common dolphins. 
Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
short-beaked common dolphins.

Harbor Porpoise

    The Navy Marine Species Density Database (U.S. Navy 2019) estimates 
the density of harbor porpoise in the Henderson Bay area as 0.86/km\2\. 
Based on this density estimate, the following number of harbor 
porpoises may be present in the Level B harassment zones:

H piles: 0.86/km\2\ * 1.36 km\2\ * 5 days = 5.848
Sheetpiles: 0.86/km\2\ * 17.9 km\2\ * 9 days = 138.546
Total Estimated Take = 144.4 animals

    We are authorizing Level B harassment of 145 harbor porpoises. 
Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
harbor porpoises.

California Sea Lion

    The Navy Marine Species Density Database (U.S. Navy 2019) estimates 
the density of California sea lions in the Henderson Bay area as 
0.2211/km\2\. Based on this density estimate, the following number of 
California sea lions may be present in the Level B harassment zones:

H piles: 0.2211/km\2\ * 1.36 km\2\ * 5 days = 1.503

[[Page 8604]]

Sheetpiles: 0.2211/km\2\ * 17.9 km\2\ * 9 days = 35.619
Needle gun: 0.2211/km\2\ * 0.01 km\2\ * 6 days = 0.013
Total Estimated Take = 37.14 animals

    We are authorizing Level B harassment of 38 California sea lions. 
Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
California sea lions.

Steller Sea Lion

    The Navy Marine Species Density Database (U.S. Navy 2019) estimates 
the density of Steller sea lions in the Henderson Bay area as 0.0478/
km\2\. Based on this density estimate, the following number of Steller 
sea lions may be present in the Level B harassment zones:

H piles: 0.0478/km\2\ * 1.36 km\2\ * 5 days = 0.325
Sheetpiles: 0.0478/km\2\ * 17.9 km\2\ * 9 days = 7.70
Needle gun: 0.0478/km\2\ * 0.01 km\2\ * 6 days = 0.007
Total Estimated Take = 8.03 animals

    We are authorizing for Level B harassment of nine Steller sea 
lions. Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
Steller sea lions.

Harbor Seal

    The Navy Marine Species Density Database (U.S. Navy 2019) estimates 
the density of harbor seal in the Henderson Bay area as 3.91/km\2\. 
Based on this density estimate, the following number of harbor seals 
may be present in the Level B harassment zones:

H piles: 3.91/km\2\ * 1.36 km\2\ * 5 days = 26.588
Sheetpiles: 3.91/km\2\ * 17.9 km\2\ * 9 days = 629.901
Needle gun: 3.91/km\2\ * 0.06 km\2\ * 6 days = 1.408
Total Estimated Take = 657.9 animals

    We are authorizing for Level B harassment of 658 harbor seals. 
Because the Level A harassment zones are relatively small and we 
believe the PSO will be able to effectively monitor the Level A 
harassment zones, we do not authorize take by Level A harassment of 
Steller sea lions.

 Table 7--Authorized Amount of Taking, by Level A Harassment and Level B
      Harassment, by Species and Stock and Percent of Take by Stock
------------------------------------------------------------------------
                                                            Percent of
                 Species                   Take request        stock
------------------------------------------------------------------------
Harbor seal.............................             658             (*)
California sea lion.....................              38           < 0.1
Steller sea lion........................               9           < 0.1
Gray whale..............................              10             0.4
Short-beaked common dolphin.............              50           < 0.1
Harbor porpoise.........................             145             1.3
------------------------------------------------------------------------
* There is no official estimate of stock size for this stock.

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses (latter not applicable for this action). NMFS 
regulations require applicants for incidental take authorizations to 
include information about the availability and feasibility (economic 
and technological) of equipment, methods, and manner of conducting the 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The following mitigation measures are in the IHA:
     For in-water heavy machinery work other than pile driving/
removal (e.g., standard barges, etc.), and for needle gun 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. This type of work could include the 
following activities: (1) Movement of the barge to or around the pile 
location; or (2) positioning of the pile on the substrate via a crane 
(i.e., stabbing the pile);
     Conduct briefings between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of all 
pile driving/removal activity and when new personnel join the work, to 
explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures;
     For those marine mammals for which Level B harassment take 
has not been requested, in-water pile installation/removal will shut 
down immediately if such species are observed within or entering the 
Level B harassment zone; and
     If take reaches the authorized limit for an authorized 
species, pile installation/removal will be stopped as these species 
approach the Level B harassment zone to avoid additional take.
    The following mitigation measures would apply to WADOT's in-water 
construction activities.

[[Page 8605]]

     Establishment of Shutdown Zones--WADOT will establish 
shutdown zones for all pile driving and removal activities (Table 8). 
The purpose of a shutdown zone is generally to define an area within 
which shutdown of the activity would occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area). 
Shutdown zones typically vary based on the activity type and marine 
mammal hearing group (Table 2). Because the zones are small in this 
project, and WADOT seeks to simplify their monitoring, they have 
requested to establish shutdown zones of the same size that apply 
separately to cetaceans and pinnipeds, rather than having multiple size 
zones within each of these marine mammal groups corresponding to each 
hearing group. Therefore the shutdown zones are based on the largest 
Level A harassment zone within the cetacean and pinniped groups, 
respecitively, with an absolute minimum shutdown zone size of 10 m (33 
ft).
     Pile wake-up--When removing piles WADOT will shake the 
pile slightly prior to removal to break the bond with surrounding 
sediment to avoid pulling out large blocks of sediment. Piles they will 
also be removed slowly to minimize turbidity.
     The placement of Protected Species Observers (PSOs) during 
all pile driving and removal activities (described in detail in the 
Monitoring and Reporting section) will ensure that the entire shutdown 
zone is visible during pile installation. Should environmental 
conditions deteriorate such that marine mammals within the entire 
shutdown zone would not be visible (e.g., fog, heavy rain), pile 
driving and removal must be delayed until the PSO is confident marine 
mammals within the shutdown zone could be detected.
     Monitoring for Level B Harassment--WADOT will monitor the 
Level A and B harassment and shutdown zones. Monitoring zones provide 
utility for observing by establishing monitoring protocols for areas 
adjacent to the shutdown zones. Monitoring zones enable observers to be 
aware of and communicate the presence of marine mammals in the project 
area outside the shutdown zone and thus prepare for a potential halt of 
activity should the animal enter the shutdown zone. Placement of PSOs 
will allow PSOs to observe marine mammals within the Level B harassment 
zones that serve as monitoring zones.
     Pre-activity Monitoring--Prior to the start of daily in-
water construction activity, or whenever a break in pile driving/
removal of 30 minutes or longer occurs, PSOs will observe the shutdown 
and monitoring 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, a soft-start cannot proceed until the animal 
has 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 and Level 
B harassment take will be recorded. 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.
     Pile driving or removal must occur during daylight hours.
    Based on our evaluation of the applicant's measures, as well as 
other measures considered by NMFS, NMFS has determined that the 
mitigation measures provide the means effecting the least practicable 
impact on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance.

               Table 8--Shutdown Zones (Radius in Meters) by Pile Type, Activity and Hearing Group
----------------------------------------------------------------------------------------------------------------
            Pile type              Low frequency   Mid frequency  High frequency      Otariid         Phocid
----------------------------------------------------------------------------------------------------------------
Sheet...........................              50              50              50              20              20
H pile..........................              10              10              10              10              10
----------------------------------------------------------------------------------------------------------------

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed 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.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
Monitoring Plan and section 5 of the IHA. Marine mammal monitoring 
during pile driving and removal must be conducted by NMFS-approved PSOs 
in a manner consistent with the following:

[[Page 8606]]

     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods must be used;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
     WADOT must submit PSO Curriculum Vitae for approval by 
NMFS prior to the onset of pile driving.
    PSOs must have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    Up to four PSOs will be employed. PSO locations will provide an 
unobstructed view of all water within the shutdown zone, and as much of 
the Level A and Level B harassment zones as possible. PSO locations are 
as follows:
    (1) At the pile driving/removal site or best vantage point 
practicable to monitor the shutdown zones and the small area north into 
Burley Lagoon;
    (2) At Purdy Spit Park to monitor the Level B harassment zone near 
the project site in Henderson Bay; and
    (3) For the smaller Level B harassment zone associated with H pile 
driving/removal, an additional PSOs will be located on the southeast 
end of the level B harassment zone (see Monitoring Plan Figure 4);
    (4) For the larger Level B harassment zone associated with 
sheetpile driving/removal PSOs will be at the pile/driving removal site 
and Purdy Spit park as described above. Two additional PSOs will be 
located further south in Henderson Bay (see Monitoring Plan Figure 2): 
One at Kopachuck State Park to monitor the southern end of the Level B 
harassment zone and one further south at Penrose Point State Park to 
monitor the approaches into Henderson Bay, especially for killer and 
humpback whales and other large whales not authorized for take.
    Monitoring will be conducted 30 minutes before, during, and 30 
minutes after pile driving/removal activities. In addition, observers 
shall record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven or removed. Pile driving 
activities include the time to install or remove a single pile or 
series of piles, as long as the time elapsed between uses of the pile 
driving or drilling equipment is no more than 30 minutes.

Reporting

    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities, or 60 days prior to a requested date of issuance of any 
future IHAs for projects at the same location, whichever comes first. 
The report will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including how many and what type of piles were 
driven or removed and by what method (i.e., impact or vibratory and if 
other removal methods were used);
     Weather parameters and water conditions during each 
monitoring period (e.g., wind speed, percent cover, visibility, sea 
state);
     The number of marine mammals observed, by species, 
relative to the pile location and if pile driving or removal was 
occurring at time of sighting;
     Age and sex class, if possible, of all marine mammals 
observed;
     PSO locations during marine mammal monitoring;
     Distances and bearings of each marine mammal observed to 
the pile being driven or removed for each sighting (if pile driving or 
removal was occurring at time of sighting);
     Description of any marine mammal behavior patterns during 
observation, including direction of travel and estimated time spent 
within the Level A and Level B harassment zones while the source was 
active;
     Number of individuals of each species (differentiated by 
month as appropriate) detected within the monitoring zone, and 
estimates of number of marine mammals taken, by species (a correction 
factor may be applied to total take numbers, as appropriate);
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal, if 
any; and
     Description of attempts to distinguish between the number 
of individual animals taken and the number of incidences of take, such 
as ability to track groups or individuals.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, WADOT shall report the 
incident to the Office of Protected Resources (OPR), NMFS and to the 
regional stranding coordinator as soon as feasible. If the death or 
injury was clearly caused by the specified activity, WADOT must 
immediately cease the specified activities until NMFS is able to review 
the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of the IHA. The IHA-holder must not resume their activities until 
notified by NMFS. The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the

[[Page 8607]]

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., population-level effects). An estimate of the number of 
takes alone is not enough information on which to base an impact 
determination. In addition to considering estimates of the number of 
marine mammals that might be ``taken'' through harassment, NMFS 
considers other factors, such as the likely nature of any responses 
(e.g., intensity, duration), the context of any responses (e.g., 
critical reproductive time or location, migration), as well as effects 
on habitat, and the likely effectiveness of the mitigation. We also 
assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS's implementing regulations (54 FR 
40338; September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the environmental baseline (e.g., as reflected in the 
regulatory status of the species, population size and growth rate where 
known, ongoing sources of human-caused mortality, or ambient noise 
levels).
    To avoid repetition, the discussion of our analyses applies to all 
the species listed in Table 7, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. There is little information about the nature or severity of 
the impacts, or the size, status, or structure of any of these species 
or stocks that would lead to a different analysis for this activity. 
Pile driving activities have the potential to disturb or displace 
marine mammals. Specifically, the project activities may result in 
take, in the form of Level B harassment from underwater sounds 
generated from pile driving and removal and needle gun use. Potential 
takes could occur if individuals are present in the ensonified zone 
when these activities are underway.
    Takes by Level B harassment would be in the form of behavioral 
disturbance and/or TTS. No mortality or PTS (Level A harassment) is 
anticipated given the nature of the activity and measures designed to 
minimize the possibility of injury to marine mammals. The potential for 
harassment is minimized through the construction method and the 
implementation of the planned mitigation measures (see Mitigation 
section).
    The nature of the pile driving project precludes the likelihood of 
serious injury or mortality. Take would occur within a limited, 
confined area (north-central Henderson Bay) of the stock's range. Level 
A and Level B harassment will be reduced to the level of least 
practicable adverse impact through use of mitigation measures described 
herein, and as a result, as discussed above, Level A harassment is not 
anticipated to occur. Further the amount of take authorized is 
extremely small when compared to stock abundance.
    Behavioral responses of marine mammals to pile driving and needle 
gun use at the project site, if any, are expected to be mild and 
temporary. Marine mammals within the Level B harassment zone may not 
show any visual cues they are disturbed by activities (as noted during 
modification to the Kodiak Ferry Dock (see 80 FR 60636, October 7, 
2015)) or could become alert, avoid the area, leave the area, or 
display other mild responses that are not observable such as changes in 
vocalization patterns. Given the short duration of noise-generating 
activities per day and that pile driving and removal would occur across 
three months, any harassment would be temporary. There are no other 
areas or times of known biological importance for any of the affected 
species.
    In addition, it is unlikely that minor noise effects in a small, 
localized area of habitat would have any effect on the fitness of any 
individual or the stocks' ability to recover. In combination, we 
believe that these factors, as well as the available body of evidence 
from other similar activities, demonstrate that the potential effects 
of the specified activities will have only minor, short-term effects on 
individuals. The specified activities are not expected to impact rates 
of recruitment or survival and will therefore not result in population-
level impacts.
    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 or Level A harassment is anticipated or 
authorized;
     No biologically important areas have been identified 
within the project area;
     For all species, Henderson Bay is a very small and 
peripheral part of their range;
     WADOT would implement mitigation measures such as shut 
downs and slow removal of piles to minimize turbidity and shaking the 
pile slightly prior to removal (wake up) to break the bond with 
surrounding sediment to avoid pulling out large blocks of sediment; and
     Monitoring reports from similar work in Puget Sound have 
documented little to no effect on individuals of the same species 
impacted by the specified activities.
    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 
proposed activity will have a negligible impact on all affected marine 
mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of the relevant species or stock in 
our determination of whether an authorization is limited to small 
numbers of marine mammals. When the predicted number of individuals to 
be taken is fewer than one third of the species or stock abundance, the 
take is considered to be of small numbers. Additionally, other 
qualitative factors may be considered in the analysis, such as the 
temporal or spatial scale of the activities.
    The amount of take NMFS authorizes is below one third of the 
estimated stock abundance for all stocks. For harbor seals there are no 
official estimates of the stock size. We do know the populations of 
harbor seals in Puget Sound are increasing and number at least 32,000 
(Jeffries, 2013). We also know that harbor seals do not generally range 
over large areas (see above). Therefore, it is most likely that the 
number of harbor seal takes is a small number. For all stocks, these 
are all likely conservative estimates of percent of stock taken because 
they assume all takes are of different individual animals which is 
likely not the case. Some individuals may return multiple times in a 
day, but PSOs would count them as separate takes if they cannot be 
individually identified.
    Based on the analysis contained herein of the proposed activity 
(including the mitigation and monitoring measures) and the

[[Page 8608]]

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.

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 (IHAs 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 we have 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.

Endangered Species Act

    Section 7(a)(2) of the 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, in this 
case with the West Coast Region Protected Resources Division Office, 
whenever we propose to authorize take for endangered or threatened 
species.
    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.

Authorization

    NMFS has issued an IHA to WADOT for the potential harassment of 
small numbers of six marine mammal species incidental to the Purdy 
Bridge Rehabilitation project in Pierce, WA, provided the previously 
mentioned mitigation, monitoring and reporting requirements are 
followed.

    Dated: February 1, 2021.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-02489 Filed 2-5-21; 8:45 am]
BILLING CODE 3510-22-P