Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Notices 30613 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

[Docket No. FWS–R7–ES–2020–0132; 

FXES111607MRG01–212–FF07CAMM00] 

Marine Mammals; Incidental Take 

During Specified Activities; Proposed 

Incidental Harassment Authorization 

for Southeast Alaska Stock of Northern 

Sea Otters in the Queen Charlotte Fault 

Region, Alaska 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Notice of receipt of application; 

proposed incidental harassment 

authorization; request for comments. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service, in response to a 

request under the Marine Mammal 

Protection Act of 1972, as amended, 

from the National Science Foundation 

and the Lamont-Doherty Earth 

Observatory, propose to authorize 

nonlethal, incidental take by harassment 

of small numbers of the Southeast 

Alaska stock of northern sea otters 

between July 1, 2021, and August 31, 

2021. The applicants have requested 

this authorization for take that may 

result from high-energy seismic surveys 

in the Queen Charlotte Fault region of 

Southeast Alaska. Seismic surveys are 

being conducted to characterize crustal 

and uppermost mantle velocity 

structure, fault zone architecture and 

rheology, and seismicity in the Queen 

Charlotte Fault. We estimate that this 

project may result in the nonlethal 

incidental take of up to 27 northern sea 

otters from the Southeast Alaska stock. 

This proposed authorization, if 

finalized, will be for up to 49 takes of 

27 northern sea otters by Level B 

harassment only. No injury or mortality 

is expected or will be authorized. 

DATES: Comments on the proposed 

incidental harassment authorization and 

draft environmental assessment must be 

received by July 9, 2021. 

ADDRESSES: Document availability: You 

may view this proposed authorization, 

the application package, supporting 

information, and the lists of references 

cited herein at http://

www.regulations.gov under Docket No. 

FWS–R7–ES–2020–0132, or these 

documents may be requested as 

described under FOR FURTHER

INFORMATION CONTACT. 

Comment submission: You may 

submit comments on this proposed 

authorization by one of the following 

methods: 

• U.S. mail: Public Comments 

Processing, Attn: Docket No. FWS–R7– 

ES–2020–0132, U.S. Fish and Wildlife 

Service, MS: PRB/3W, 5275 Leesburg 

Pike, Falls Church, Virginia 22041– 

3803. 

• Electronic submission: Federal 

eRulemaking Portal at: http://

www.regulations.gov. Follow the 

instructions for submitting comments to 

Docket No. FWS–R7–ES–2020–0132. 

We will post all comments at http://

www.regulations.gov. You may request 

that we withhold personal identifying 

information from public review; 

however, we cannot guarantee that we 

will be able to do so. See Request for 

Public Comments for more information. 

FOR FURTHER INFORMATION CONTACT: 

Marine Mammals Management, U.S. 

Fish and Wildlife Service, MS–341, 

1011 East Tudor Road, Anchorage, 

Alaska, 99503, by email at 

R7mmmregulatory@fws.gov; or by 

telephone at 1–800–362–5148. Persons 

who use a telecommunications device 

for the deaf (TDD) may call the Federal 

Relay Service (FRS) at 1–800–877–8339, 

24 hours a day, 7 days a week. 

SUPPLEMENTARY INFORMATION: 

Background 

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

Mammal Protection Act of 1972 

(MMPA; 16 U.S.C. 1361, et seq.), 

authorizes the Secretary of the Interior 

(Secretary) to allow, upon request, the 

incidental but not intentional taking of 

small numbers of marine mammals of a 

species or population stock by U.S. 

citizens who engage in a specified 

activity (other than commercial fishing) 

within a specified region during a 

period of not more than one year. 

Incidental take may be authorized only 

if statutory and regulatory procedures 

are followed and the U.S. Fish and 

Wildlife Service (hereafter, ‘‘the 

Service’’ or ‘‘we’’) makes the following 

findings: (i) Take is of a small number 

of marine mammals of a species or 

population stock, (ii) take will have a 

negligible impact on the species or 

stock, and (iii) take will not have an 

unmitigable adverse impact on the 

availability of the species or stock for 

subsistence uses by coastal-dwelling 

Alaska Natives. 

The term ‘‘take,’’ as defined by the 

MMPA, means to harass, hunt, capture, 

or kill, or to attempt to harass, hunt, 

capture, or kill any marine mammal (16 

U.S.C. 1362(13)). Harassment, as 

defined by the MMPA, means any act of 

pursuit, torment, or annoyance that (i) 

has the potential to injure a marine 

mammal or marine mammal stock in the 

wild (the MMPA defines this as ‘‘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 (the MMPA defines this as 

‘‘Level B harassment’’). 

The terms ‘‘negligible impact,’’ ‘‘small 

numbers,’’ and ‘‘unmitigable adverse 

impact’’ are defined in the Code of 

Federal Regulations at 50 CFR 18.27, the 

Service’s regulations governing take of 

small numbers of marine mammals 

incidental to specified activities. 

‘‘Negligible impact’’ is defined 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. ‘‘Small 

numbers’’ is defined as a portion of a 

marine mammal species or stock whose 

taking would have a negligible impact 

on that species or stock. However, we 

do not rely on that definition, as it 

conflates the terms ‘‘small numbers’’ 

and ‘‘negligible impact,’’ which we 

recognize as two separate and distinct 

requirements (see Natural Res. Def. 

Council, Inc. v. Evans, 232 F. Supp. 2d 

1003, 1025 (N.D. Cal. 2003)). Instead, in 

our small numbers determination, we 

evaluate whether the number of marine 

mammals likely to be taken is small 

relative to the size of the overall 

population. ‘‘Unmitigable adverse 

impact’’ is defined as an impact 

resulting from the specified activity (1) 

that is likely to reduce the availability 

of the species to a level insufficient for 

a harvest to meet subsistence needs by 

(i) causing the marine mammals to 

abandon or avoid hunting areas, (ii) 

directly displacing subsistence users, or 

(iii) placing physical barriers between 

the marine mammals and the 

subsistence hunters; and (2) that cannot 

be sufficiently mitigated by other 

measures to increase the availability of 

marine mammals to allow subsistence 

needs to be met. 

If the requisite findings are made, we 

will issue an Incidental Harassment 

Authorization (IHA), which sets forth 

the following: (i) Permissible methods of 

taking; (ii) other means of effecting the 

least practicable impact on marine 

mammals and their habitat, paying 

particular attention to rookeries, mating 

grounds, and areas of similar 

significance, and on the availability of 

marine mammals for taking for 

subsistence uses by coastal-dwelling 

Alaska Natives; and (iii) requirements 

for monitoring and reporting take. 

Summary of Request 

On December 2, 2019, the National 

Science Foundation and LamontDoherty Earth Observatory (hereafter 


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30614 Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Notices 

‘‘NSF/L–DEO’’ or ‘‘the applicant’’) 

submitted a request to the Service’s 

Marine Mammals Management Office 

(MMM) for authorization to take by 

Level B harassment a small number of 

northern sea otters (Enhydra lutris 

kenyoni, hereafter ‘‘sea otters’’ or 

‘‘otters’’ unless another species is 

specified) from the Southeast Alaska 

stock. NSF/L–DEO expects that take by 

unintentional harassment may occur 

during their planned high-energy 

marine seismic surveys at the Queen 

Charlotte Fault (QCF) in the Northeast 

Pacific Ocean within the U.S. Exclusive 

Economic Zone (EEZ). 

Description of Specified Activities and 

Geographic Region 

The specified activity (the ‘‘project’’) 

consists of Lamont-Doherty Earth 

Observatory’s (L–DEO) 2021 Marine 

Geophysical Surveys by the Research 

Vessel (R/V) Marcus G. Langseth 

(Langseth) of the QCF in the Northeast 

Pacific Ocean from July 1, 2021, to 

August 31, 2021. High-energy twodimensional (2–D) seismic surveys will 

be used to characterize crustal and 

uppermost mantle velocity structure, 

fault zone architecture and rheology, 

and seismicity of the QCF. The 2–D 

seismic surveys will be conducted along 

transect lines within the area of 52–57° 

N and 131–137° W (Figure 1). Some 

deviation in actual transects, including 

order of survey operations, could be 

necessary due to poor data quality, 

inclement weather, or mechanical issues 

with the research vessel or equipment. 

The surveys are proposed to occur 

within the EEZs of the United States 

and Canada, including U.S. Federal 

Waters, State of Alaska Waters, and 

Canadian Territorial Waters ranging 

from 50 to 2,800 meters (m; 164 to 9,186 

feet (ft)) in depth. The Service cannot 

and is not authorizing the incidental 

take of marine mammals in waters not 

under the jurisdiction of the United 

States. Therefore, the Service’s 

calculation of estimated incidental take 

is limited to the specified activity 

occurring in United States jurisdictional 

waters within the stock’s range. The 

proposed surveys are anticipated to last 

for 36 days, including approximately 27 

days of seismic operations, 

approximately 2 days of transit to and 

from the survey area, 3 days for 

equipment deployment/recovery, and 4 

days of contingency. The R/V Langseth 

will likely leave out of and return to the 

port of Ketchikan, AK, during summer 

2021. 

The R/V Langseth will tow 4 strings 

containing an array of 36 airguns at a 

depth of 12 m (39 ft), creating a 

discharge volume of approximately 0.11 

cubic meter (m3; 6,600 cubic inches 

(in3)). The peak sound pressure 1 m (3.2 

ft) from the center of the airgun array is 

258.6 decibels (Tolstoy et al. 2009). 

Noise levels herein are given in decibels 

(dB) referenced to 1 mPa (dB re: 1 mPa) 

for underwater sound. All dB levels are 

dBRMS (root-mean-squared dB level) 

unless otherwise noted; dBRMS refers to 

the square root of the average of the 

squared sound pressure level typically 

measured over 1 second. Other 

important metrics include the sound 

exposure level (SEL; represented as dB 

re: 1 mPa2-s), which represents the total 

energy contained within a pulse and 

considers both intensity and duration of 

exposure, and the peak sound pressure 

(also referred to as the zero-to-peak 

sound pressure or 0–p). Peak sound 

pressure is the maximum instantaneous 

sound pressure measurable in the water 

at a specified distance from the source 

and is represented in the same units as 

the dBRMS sound pressure. See 

Richardson et al. (1995), Go ̈tz et al. 

(2009), Hopp et al. (2012), Navy (2014), 

for descriptions of acoustical terms and 

measurement units in the context of 

ecological impact assessment. 

The seismic array produces 

broadband energy that ranges from a few 

hertz (Hz) to kilohertz (kHz). However, 

all but a small fraction of the energy is 

focused in the 10–300 Hz range (Tolstoy 

et al. 2009). The survey will also 

include the use of a single 655-cubiccentimeter (cm3; 40-in3) airgun that will 

be used when the full array is powered 

down. 

The receiving system will consist of a 

15-kilometer (km; 9.3-mile (mi)) 

hydrophone streamer and 

approximately 60 short-period and 28 

broadband Ocean Bottom Seismometer 

(OBS) devices, which will be primarily 

deployed from a second vessel, the 

Canadian Coast Guard R/V John P. Tully 

(however, R/V Langseth may also 

deploy OBSs). The OBSs will be 

deployed at approximately 10-km (6.2- 

mi) intervals with 5-km (3.1 mi) spacing 

over the central 40 km (25 mi) of the 

fault zone. The OBSs have a height and 

diameter of 1 m (3.2 ft) and an 80- 

kilogram (176-pound) anchor. 

Additional project details may be 

reviewed in the application materials 

available as described under ADDRESSES

or may also be requested as described 

under FOR FURTHER INFORMATION

CONTACT. 


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Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Notices 30615 

Description of Marine Mammals in the 

Specified Activity Area 

The northern sea otter is the only 

marine mammal under the Service’s 

jurisdiction that normally occupies the 

Northeast Pacific Ocean. Sea otters in 

Alaska are represented by three stocks. 

Those in the Northeast Pacific Ocean 

belong to the Southeast Alaska stock. 

Two other stocks occur in Southcentral 

and Southwest Alaska. Detailed 

information about the biology of the 

Southeast Alaska stock can be found in 

the most recent stock assessment report 

(USFWS 2014), which can be found at: 

https://www.fws.gov/r7/fisheries/mmm/ 

stock/Revised_April_2014_Southeast_

Alaska_Sea_Otter_SAR.pdf. 

Sea otters may be distributed 

anywhere within the specified project 

area other than upland areas; however, 

they generally occur in shallow water 

near the shoreline. They are most 

commonly observed within the 40-m 

(131-ft) depth contour (USFWS 2014), 

although they can be found in areas 

with deeper water. Ocean depth is 


lotter on DSK11XQN23PROD with NOTICES1EN09JN21.038</GPH>

- Northern Sea Otter Habitat 0 30 60 120 Kilometers 

~ l60d8 Ensonification Zone _--~-~----~~~I 

.t. OBS 

-- Survey Transets Spatial Reference 

Name: NAD 1983 UTM Zone 10N 

PCS: NAO 1983 UTM Zone lON 

GCS: GCS North American 1983 

Created by: S.Burgess, USFWS 

N 

A 

Figure 1. Specified geographic area for the National Science Foundation and LamontDoherty Earth Observatory seismic survey planned for summer 2021. 
30616 Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Notices 

generally correlated with distance to 

shore, and sea otters typically remain 

within 1 to 2 km (0.62 to 1.24 mi) of 

shore (Riedman and Estes 1990). They 

tend to be found closer to shore during 

storms, but they venture farther out 

during good weather and calm seas 

(Lensink 1962; Kenyon 1969). In the 14 

aerial surveys conducted from 1995 to 

2012 in Southeast Alaska, 95 percent of 

otters were found in areas shallower 

than 40 m (131 ft) (Tinker et al. 2019). 

Areas important to mating for the 

Southeast Alaska stock include marine 

coastal regions containing adequate food 

resources within the 40-m (131-ft) depth 

contour. 

The most recent estimate of the 

number of sea otters in the Southeast 

Alaska stock is 25,584 otters (standard 

error = 3,679; Tinker et al. 2019). The 

estimate was developed using a 

Bayesian hierarchical modeling 

framework based on survey and harvest 

count data. The survey data comprised 

results from 14 aerial surveys conducted 

in Southeast Alaska from 1995 to 2012, 

totaling more than 20,000 km (12,427 

mi) of aerial transects. The Service 

conducted large-scale surveys in 

cooperation with the U.S. Geological 

Survey in 2003 and 2010 in southern 

Southeast Alaska (from Kake to Duke 

Island and Cape Chacon) and in 2002 

and 2011 in northern Southeast Alaska 

(from Icy Point to Cape Ommaney). In 

these aerial surveys, transects were 

flown over high-density otter habitat 

(<40-m (131-ft) ocean depth) with a 

spacing of 2 km (1.2 mi) between 

transects and low-density otter habitat 

(40- to 100-m (131- to 328-ft) ocean 

depth) with a spacing of 8 km (5 mi) 

between transects. 

Otter densities within the Southeast 

Alaska stock have been calculated for 24 

subdivisions (Tinker et al. 2019). The 

density of otters in the affected 

subdivisions ranged from 0.175 to 1.333 

otters per km2. Distribution of the 

population during the proposed project 

is likely to be similar to that detected 

during sea otter surveys, as work will 

occur during the same time of the year 

that these surveys were conducted. 

The documented home range sizes 

and movement patterns of sea otters 

illustrate the types of movements that 

could be seen among otters responding 

to the proposed activities. Sea otters are 

non-migratory and generally do not 

disperse over long distances (Garshelis 

and Garshelis 1984). They usually 

remain within a few kilometers of their 

established feeding grounds (Kenyon 

1981). Breeding males stay for all or part 

of the year in a breeding territory 

covering up to 1 km (0.62 mi) of 

coastline while adult females have 

home ranges of approximately 8 to 16 

km (5 to 10 mi), which may include one 

or more male territories. Juveniles move 

greater distances between resting and 

foraging areas (Lensink 1962; Kenyon 

1969; Riedman and Estes 1990; Estes 

and Tinker 1996). Although sea otters 

generally remain local to an area, they 

are capable of long-distance travel. 

Otters in Alaska have shown daily 

movement distances greater than 3 km 

(1.9 mi) at speeds up to 5.5 km per hour 

(km/hr; 3.4 mi per hour (mi/h)) 

(Garshelis and Garshelis 1984). 

Potential Effects of the Specified 

Activities 

Exposure of Sea Otters to Noise 

We do not expect the operations 

outlined in the Description of Specified 

Activities and Geographic Region and 

described in the applicant’s petition to 

lead to take from vessel presence or 

anthropogenic presence. The tracklines 

for the vessels will not physically enter 

low-density or high-density sea otter 

habitat. Thus, we do not anticipate 

human–otter interactions that would 

lead to Level B harassment or other 

forms of take. 

The operations have the potential to 

result in take of sea otters by harassment 

from noise. Here, we characterize 

‘‘noise’’ as sound released into the 

environment from human activities that 

exceeds ambient levels or interferes 

with normal sound production or 

reception by sea otters. The terms 

‘‘acoustic disturbance’’ or ‘‘acoustic 

harassment’’ are disturbances or 

harassment events resulting from noise 

exposure. Potential effects of noise 

exposure are likely to depend on the 

distance of the otter from the sound 

source and the level of sound the otter 

receives. Temporary disturbance or 

localized displacement reactions are the 

most likely to occur. No lethal take is 

anticipated, nor can the Service 

authorize lethal take through an 

Incidental Take Authorization. 

Therefore, none will be authorized. 

Whether a specific noise source will 

affect a sea otter depends on several 

factors, including the distance between 

the animal and the sound source, the 

sound intensity, background noise 

levels, the noise frequency, the noise 

duration, and whether the noise is 

pulsed or continuous. The actual noise 

level perceived by individual sea otters 

will depend on distance to the source, 

whether the animal is above or below 

water, atmospheric and environmental 

conditions as well as aspects of the 

noise emitted. 

From the discussion below, we expect 

the actual number of otters experiencing 

Level B take due to harassment by noise 

to be 27 or fewer. While individual 

otters may be taken more than once, the 

total number of incidental takes of sea 

otters is expected to be less than 49. 

Sea Otter Hearing 

The NSF/L–DEO’s 36-airgun array 

will produce sound frequencies that fall 

within the hearing range of sea otters 

and will be audible to animals. 

Controlled sound exposure trials on 

southern sea otters (E. l. nereis) indicate 

that otters can hear frequencies between 

125 Hz and 38 kHz with best sensitivity 

between 1.2 and 27 kHz (Ghoul and 

Reichmuth 2014). Aerial and 

underwater audiograms for a captive 

adult male southern sea otter in the 

presence of ambient noise suggest the 

sea otter’s hearing was less sensitive to 

high-frequency (greater than 22 kHz) 

and low-frequency (less than 2 kHz) 

sound than terrestrial mustelids but was 

similar to that of a California sea lion 

(Zalophus californianus). However, the 

subject otter was still able to hear lowfrequency sounds, and the detection 

thresholds for sounds between 0.125–1 

kHz were between 116–101 dB, 

respectively. Dominant frequencies of 

southern sea otter vocalizations are 

between 3 and 8 kHz, with some energy 

extending above 60 kHz (McShane et al. 

1995; Ghoul and Reichmuth 2012). 

Exposure to high levels of sound may 

cause changes in behavior, masking of 

communications, temporary or 

permanent changes in hearing 

sensitivity, discomfort, and injury to 

marine mammals. Unlike other marine 

mammals, sea otters do not rely on 

sound to orient themselves, locate prey, 

or communicate underwater; therefore, 

masking of communications by 

anthropogenic sound is less of a concern 

than for other marine mammals. 

However, sea otters do use sound for 

communication in air (especially 

mothers and pups; McShane et al. 1995) 

and may avoid predators by monitoring 

underwater sound (Davis et al. 1987). 

Thresholds have been developed for 

some marine mammals above which 

exposure is likely to cause behavioral 

disturbance and injuries (Southall et al. 

2007; Finneran and Jenkins 2012; NMFS 

2016). However, species-specific criteria 

for sea otters has not been identified. 

Because sea otter hearing abilities and 

sensitivities have not been fully 

evaluated, we relied on the most similar 

proxy to evaluate the potential effects of 

noise exposure. 

California sea lions (otariid 

pinnipeds) have a frequency range of 

hearing most similar to that of southern 

sea otters (Ghoul and Reichmuth 2014) 

and provide the closest related proxy for 


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which data are available. Sea otters and 

pinnipeds share a common mammalian 

aural physiology (Echteler et al. 1994; 

Solntseva 2007). Both are adapted to 

amphibious hearing, and both use 

sound in the same way (primarily for inair communication rather than feeding). 

Exposure Thresholds 

The National Marine Fisheries Service 

(NMFS) established noise exposure 

criteria for identifying underwater noise 

levels capable of causing Level A 

harassment (injury) of otariid pinnipeds 

(NMFS 2018). Sea otter-specific criteria 

have not been determined. However, 

because of their biological similarities, 

we assume that NMFS’ noise exposure 

criteria for otariid pinniped injury is a 

suitable surrogate for sea otter impacts. 

Those criteria are based on estimated 

levels of sound exposure capable of 

causing a permanent shift in sensitivity 

of hearing (e.g., a permanent threshold 

shift (PTS) (NMFS 2018)). A PTS occurs 

when noise exposure causes hairs 

within the inner ear system to die. 

The NMFS (2018) criteria for sound 

exposure incorporate two metrics of 

exposure: The peak level of 

instantaneous exposure likely to cause 

PTS, and the cumulative sound 

exposure level during a 24-hour period 

(SELcum). They also include weighting 

adjustments for the sensitivity of 

different species to varying frequencies. 

The PTS-based injury criteria were 

developed from theoretical 

extrapolation of observations of 

temporary threshold shifts (TTS) 

detected in lab settings during sound 

exposure trials. Studies were 

summarized by Finneran (2015). For 

otariid pinnipeds, PTS is predicted to 

occur at 232 dB peak or 203 dB SELcum

for impulsive sound, or 219 dB SELcum

for non-impulsive (continuous) sound. 

The NMFS criteria for take by Level 

A harassment represents the best 

available information for predicting 

injury from exposure to underwater 

sound among pinnipeds, and in the 

absence of data specific to otters, we 

assume these criteria also represent 

appropriate exposure limits for Level A 

take of sea otters. 

The NMFS (2018) criteria do not 

identify thresholds for avoidance of 

Level B take. For pinnipeds, the NMFS 

has adopted a 160-dB threshold for 

Level B take from exposure to impulse 

noise and a 120-dB threshold for 

continuous noise (NMFS 1998; HESS 

1999; NMFS undated). These thresholds 

were developed from observations of 

mysticete (baleen) whales responding to 

airgun operations (e.g., Malme et al. 

1983a, b; Richardson et al. 1986, 1995) 

and from equating Level B take with 

noise levels capable of causing TTS in 

lab settings. 

We have evaluated these thresholds 

and determined that the Level B 

threshold of 120-dB for non-impulsive 

noise is not applicable to sea otters. The 

120-dB threshold is based on studies 

conducted by Malme et al. in the 1980s, 

during which gray whales (Eschrichtius 

robustus) were exposed to experimental 

playbacks of industrial noise. Gray 

whales are in the group of marine 

mammals believed to be most sensitive 

to low-frequency sounds, with an 

estimated audible frequency range of 

approximately 10 Hz to 30 kHz 

(Finneran 2015). During the study, 

conducted at St. Lawrence Island, 

Alaska, Malme et al. (1988) observed the 

behavioral responses of gray whales to 

the playback of drillship noise and 

concluded that ‘‘exposure to levels of 

120 dB or more would probably cause 

avoidance of the area by more than onehalf of the gray whales.’’ Sea otters do 

not usually occur at St. Lawrence 

Island, Alaska, but similar playback 

studies conducted off the coast of 

California (Malme 1983a, 1984) 

included a southern sea otter 

monitoring component (Riedman 1983, 

1984). While the 1983 and 1984 studies 

detected probabilities of avoidance in 

gray whales comparable to those 

reported in Malme et al. (1988), there 

was no evidence of disturbance 

reactions or avoidance in southern sea 

otters. Thus, given the different range of 

frequencies to which sea otters and gray 

whales are sensitive, the NMFS 120-dB 

threshold based on gray whale behavior 

is not appropriate for predicting sea 

otter behavioral responses, particularly 

for low-frequency sound. 

Although no specific thresholds have 

been developed for sea otters, several 

alternative behavioral response 

thresholds have been developed for 

pinnipeds. Southall et al. (2007, 2019) 

assessed behavioral response studies 

and found considerable variability 

among pinnipeds. The authors 

determined that exposures between 

approximately 90 to 140 dB generally do 

not appear to induce strong behavioral 

responses in pinnipeds in water. 

However, they found behavioral effects, 

including avoidance, become more 

likely in the range between 120 to 160 

dB, and most marine mammals showed 

some, albeit variable, responses to 

sound between 140 to 180 dB. Wood et 

al. (2012) later adapted the approach 

identified in Southall et al. (2007) to 

develop a probabilistic scale for marine 

mammal taxa at which 10 percent, 50 

percent, and 90 percent of individuals 

exposed are assumed to produce a 

behavioral response. For many marine 

mammals, including pinnipeds, these 

response rates were set at sound 

pressure levels of 140, 160, and 180 dB, 

respectively. 

Based on the lack of sea otter 

disturbance response or any other 

reaction to the 1980’s playback studies 

and the absence of a clear pattern of 

disturbance or avoidance behaviors 

attributable to underwater sound levels 

up to about 160 dB resulting from lowfrequency broadband noise, we assume 

120 dB is not an appropriate behavioral 

response threshold for sea otters 

exposed to continuous underwater 

noise. 

Thresholds based on TTS have been 

used as a proxy for Level B harassment 

(i.e., 70 FR 1871, January 11, 2005; 71 

FR 3260, January 20, 2006; and 73 FR 

41318, July 18, 2008). Southall et al. 

(2007) derived TTS thresholds for 

pinnipeds based on 212 dB peak and 

171 dB SELcum. Exposures resulting in 

TTS in pinnipeds were found to range 

from 152 to 174 dB (183 to 206 dB SEL) 

(Kastak et al. 2005), with a persistent 

TTS, if not a PTS, after 60 seconds of 

184 dB SEL (Kastak et al. 2008). 

Kastelein et al. (2012) found small but 

statistically significant TTSs at 

approximately 170 dB SEL (136 dB, 60 

minutes (min)) and 178 dB SEL (148 dB, 

15 min). Finneran (2015) summarized 

these and other studies, and the NMFS 

(2018) has used the data to develop TTS 

threshold for otariid pinnipeds of 188 

dB SELcum for impulsive sounds and 199 

dB SELcum for non-impulsive sounds. 

Exposure to impulsive sound levels 

greater than 160 dB can elicit behavioral 

changes in marine mammals that may 

lead to detrimental disruption of normal 

behavioral routines. Thus, using 

information available for other marine 

mammals as a surrogate and taking into 

consideration the best available 

scientific information about sea otters, 

the Service has set 160 dB of received 

underwater sound as a threshold for 

Level B take by disturbance for sea 

otters for this proposed IHA based on 

the work of Ghoul and Reichmuth 

(2012a, b), McShane et al. (1995), 

NOAA (2005), Riedman (1983), 

Richardson et al. (1995), and others. 

Exposure to unmitigated in-water noise 

levels between 125 Hz and 38 kHz that 

are greater than 160 dB—for both 

impulsive and non-impulsive sound 

sources—will be considered by the 

Service as Level B take; thresholds for 

potentially injurious Level A take will 

be 232 dB peak or 203 dB SEL for 

impulsive sounds and 219 dB SEL for 

continuous sounds (Table 1). 

The area in which underwater noise 

in the frequency range of sea otter 

hearing will exceed thresholds is termed 


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the ‘‘zone of ensonification.’’ The 

ensonification zone in which noise 

levels exceed thresholds for Level A 

harassment is often referred to as the 

Level A harassment zone. The Level B 

harassment zone likewise includes areas 

ensonified to thresholds for Level B 

harassment of sea otters and extends 

from the sound source to the 160-dB 

isopleth. 

TABLE 1—SUMMARY OF THRESHOLDS FOR PREDICTING LEVEL A AND LEVEL B TAKE OF NORTHERN SEA OTTERS FROM

UNDERWATER SOUND EXPOSURE IN THE FREQUENCY RANGE 125 HZ–38 KHZ

Marine mammals 

Injury (Level A) threshold Disturbance 

(Level B) 

threshold 

Impulsive 1 Non-impulsive 1

All 

Sea otters ................................................ 232 dB peak; 203 dB SELCUM ............... 219 dB SELCUM 2 ................................... 160 dBRMS. 

1Based on National Marine Fisheries Service acoustic exposure criteria for take of otariid pinnipeds (NMFS 2018). 

2SELCUM = cumulative sound exposure level. 

Evidence From Sea Otter Studies 

The available studies of sea otter 

behavior suggest that sea otters may be 

more resistant to the effects of sound 

disturbance and human activities than 

other marine mammals. For example, at 

Soberanes Point, California, Riedman 

(1983) examined changes in the 

behavior, density, and distribution of 

southern sea otters that were exposed to 

recorded noises associated with oil and 

gas activity. The underwater sound 

sources were played at a level of 110 dB 

and a frequency range of 50 Hz to 20 

kHz and included production platform 

activity, drillship, helicopter, and semisubmersible sounds. Riedman (1983) 

also observed the sea otters during 

seismic airgun shots fired at decreasing 

distances from the nearshore 

environment (50, 20, 8, 3.8, 3, 1, and 0.5 

nautical miles (nm)) at a firing rate of 4 

shots per minute and a maximum air 

volume of 4,070 in3. Riedman (1983) 

observed no changes in the presence, 

density, or behavior of sea otters as a 

result of underwater sounds from 

recordings or airguns, even at the closest 

distance of 0.5 nm (<1 km or 0.6 mi). 

However, otters did display slight 

reactions to airborne engine noise. 

Riedman (1983, 1984) also monitored 

the behavior of sea otters along the 

California coast while they were 

exposed to a single 1,638-cm3 (100-in3) 

airgun and a 67,006-cm3 (4,089-in3) 

airgun array. Sea otters did not respond 

noticeably to the single airgun, and no 

disturbance reactions were evident 

when the airgun array was as close as 

0.9 km (0.6 mi). 

While at the surface, turbulence from 

wind and waves attenuates noise more 

quickly than in deeper water, reducing 

potential noise exposure (Greene and 

Richardson 1988; Richardson et al. 

1995). Additionally, turbulence at the 

water’s surface limits the transference of 

sound from water to air. A sea otter with 

its head above water will be exposed to 

only a small fraction of the sound 

energy travelling through the water 

beneath it. The average time spent above 

the water each day resting and grooming 

varies between male and female sea 

otters and seasonally. Esslinger et al. 

(2014) found in the summer months 

(i.e., the season when the proposed 

action will take place), female otters 

foraged for an average of 8.78 hours per 

day, while male otters foraged for an 

average of 7.85 hours per day. Male and 

female sea otters spent an average of 63 

to 67 percent of their summer days at 

the surface resting and grooming. The 

amount of total time spent at the surface 

may help limit sea otters’ exposure 

during noise-generating operations. 

Sea otters generally show a high 

degree of tolerance to noise. In another 

study using prerecorded sounds, Davis 

et al. (1988) exposed both northern sea 

otters in Simpson Bay, Alaska, and 

southern sea otters in Morro Bay, 

California, to a variety of airborne and 

underwater sounds, including a warble 

tone, sea otter pup calls, killer whale 

calls, air horns, and an underwater 

noise harassment system designed to 

drive marine mammals away from crude 

oil spills. The sounds were projected at 

a variety of frequencies, decibel levels, 

and intervals. The authors noted that 

certain noises could cause a startle 

response and result in movement away 

from a noise source. However, the 

effects were limited in range (no 

responses were observed for otters 

approximately 100–200 m (328–656 ft) 

from the source of the stimuli), and 

otters stopped moving away as a result 

of the stimuli within hours or, at most, 

3 to 4 days. 

In locations that lack frequent human 

activity, sea otters appear to have a 

lower threshold for outward signs of 

disturbance. Sea otters in Alaska have 

exhibited escape behaviors in response 

to the presence and approach of vessels. 

Behaviors included diving or actively 

swimming away from a boat, hauled-out 

sea otters entering the water, and groups 

of sea otters disbanding and swimming 

in multiple different directions (Udevitz 

et al. 1995). Sea otters in Alaska have 

also been shown to avoid areas with 

heavy boat traffic but return to those 

same areas during seasons with less 

traffic (Garshelis and Garshelis 1984). In 

Cook Inlet, otters drifting on a tide 

trajectory that would have taken them 

within 500 m (0.3 mi) of an active 

offshore drilling rig tended to swim to 

change their angle of drift to avoid a 

close approach despite near-ambient 

noise levels from the work (BlueCrest 

2013). 

Individual sea otters in Southeast 

Alaska will likely show a range of 

responses to noise from NSF/L–DEO’s 

survey equipment and vessels. Some 

otters will likely show startle responses, 

change direction of travel, diving, or 

premature surfacing. Sea otters reacting 

to survey activities may divert time and 

attention from biologically important 

behaviors, such as feeding. Some 

animals may abandon the survey area 

and return when the disturbance has 

ceased. Based on the observed 

movement patterns of wild sea otters 

(i.e., Lensink 1962; Kenyon 1969, 1981; 

Garshelis and Garshelis 1984; Riedman 

and Estes 1990; Estes and Tinker 1996), 

we expect some individuals, 

independent juveniles, for example, will 

respond to NSF/L–DEO’s proposed 

survey by dispersing to areas of suitable 

habitat nearby, while others, especially 

breeding-age adult males, will not be 

displaced by vessels. 

Consequences of Disturbance 

The reactions of wildlife to 

disturbance can range from short-term 

behavioral changes to long-term impacts 

that affect survival and reproduction. 

When disturbed by noise, animals may 

respond behaviorally (e.g., escape 

response) or physiologically (e.g., 

increased heart rate, hormonal response) 

(Harms et al. 1997; Tempel and 


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Gutierrez 2003). The energy expense 

and associated physiological effects 

could ultimately lead to reduced 

survival and reproduction (Gill and 

Sutherland 2000; Frid and Dill 2002). 

For example, South American sea lions 

(Otaria byronia) visited by tourists 

exhibited an increase in the state of 

alertness and a decrease in maternal 

attendance and resting time on land, 

thereby potentially reducing population 

size (Pavez et al. 2015). In another 

example, killer whales (Orcinus orca) 

that lost feeding opportunities due to 

boat traffic faced a substantial (18 

percent) estimated decrease in energy 

intake (Williams et al. 2006). Such 

disturbance effects can have populationlevel consequences. Increased 

disturbance rates have been associated 

with a decline in abundance of 

bottlenose dolphins (Tursiops sp.; 

Bejder et al. 2006; Lusseau et al. 2006). 

These examples illustrate direct 

effects on survival and reproductive 

success, but disturbances can also have 

indirect effects. Response to noise 

disturbance is considered a nonlethal 

stimulus that is similar to an 

antipredator response (Frid and Dill 

2002). Sea otters are susceptible to 

predation, particularly from killer 

whales and eagles, and have a welldeveloped antipredator response to 

perceived threats. For example, the 

presence of a harbor seal (Phoca 

vitulina) did not appear to disturb sea 

otters, but they demonstrated a fear 

response in the presence of a California 

sea lion by actively looking above and 

beneath the water (Limbaugh 1961). 

Although an increase in vigilance or 

a flight response is nonlethal, a tradeoff 

occurs between risk avoidance and 

energy conservation. An animal’s 

reactions to noise disturbance may 

cause stress and direct an animal’s 

energy away from fitness-enhancing 

activities such as feeding and mating 

(Frid and Dill 2002; Goudie and Jones 

2004). For example, southern sea otters 

in areas with heavy recreational boat 

traffic demonstrated changes in 

behavioral time budgeting showing 

decreased time resting and changes in 

haul-out patterns and distribution 

(Benham et al. 2005; Maldini et al. 

2012). Chronic stress can also lead to 

weakened reflexes, lowered learning 

responses (Welch and Welch 1970; van 

Polanen Petel et al. 2006), compromised 

immune function, decreased body 

weight, and abnormal thyroid function 

(Seyle 1979). 

Changes in behavior resulting from 

anthropogenic disturbance can include 

increased agonistic interactions between 

individuals or temporary or permanent 

abandonment of an area (Barton et al. 

1998). The intensity of disturbance 

(Cevasco et al. 2001), the extent of 

previous exposure to humans (Holcomb 

et al. 2009), the type of disturbance 

(Andersen et al. 2012), and the age or 

sex of the individuals (Shaughnessy et 

al. 2008; Holcomb et al. 2009) may 

influence the type and extent of 

response. 

Effects on Habitat and Prey 

Physical and biological features of 

habitat essential to the conservation of 

sea otters include the benthic 

invertebrates (urchins, mussels, clams, 

etc.) that otters eat and the shallow 

rocky areas and kelp beds that provide 

cover from predators. Important sea 

otter habitat in the NSF/L–DEO project 

area include coastal areas within the 40- 

m (131-ft) depth contour where high 

densities of otters have been detected. 

The MMPA allows the Service to 

identify avoidance and minimization 

measures for effecting the least 

practicable impact of the specified 

activity on important habitats. 

Geophysical surveys conducted by NSF/ 

L–DEO may impact sea otters within 

this important habitat, however, the 

project is not likely to cause lasting 

effects to habitat. 

The primary prey species for sea 

otters are sea urchins, abalone, clams, 

mussels, crabs, and squid (Tinker and 

Estes 1999). When preferential prey are 

scarce, otters will also eat kelp, turban 

snails (Tegula spp.), octopuses (e.g., 

Octopus spp.), barnacles (Balanus spp.), 

sea stars (e.g., Pycnopodia 

helianthoides), scallops (e.g., 

Patinopecten caurinus), rock oysters 

(Saccostrea spp.), worms (e.g., 

Eudistylia spp.), and chitons (e.g., 

Mopalia spp.) (Riedman and Estes 

1990). A shift to less-preferred prey 

species may result in more energy spent 

foraging or processing the prey items; 

however, the impacts of a change in 

energy expenditure is not likely seen at 

the population level (Newsome et al. 

2015). 

Several recent reviews and empirical 

studies have addressed the effects of 

noise on invertebrates (Carroll et al. 

2017). Behavioral changes, such as an 

increase in lobster (Homanus 

americanus) feeding levels (Payne et al. 

2007), an increase in wild-caught 

captive reef squid (Sepioteuthis 

australis) avoidance behavior (Fewtrell 

and McCauley 2012), and deeper 

digging by razor clams (Sinonovacula 

constricta; Peng et al. 2016) have been 

observed following experimental 

exposures to sound. Physical changes 

have also been seen in response to 

increased sound levels, including 

changes in serum biochemistry and 

hepatopancreatic cells in a lobster 

species (H. americanus; Payne et al. 

2007) and long-term damage to the 

statocysts required for hearing in several 

cephalopod species (Andre et al. 2011; 

Sole et al. 2013). 

The effects of increased sound levels 

on benthic invertebrate larvae have been 

mixed. Desoto et al. (2013) found 

impaired embryonic development in 

scallop (Pecten novaezelandiae) larvae 

when exposed to 160 dB. Christian et al. 

(2004) noted a reduction in the speed of 

egg development of bottom-dwelling 

crabs following exposure to noise; 

however, the sound level (221 dB at 2 

m or 6.6 ft) was far higher than the 

proposed seismic array will produce. 

While these studies provide evidence 

of deleterious effects to invertebrates as 

a result of increased sound levels, 

Carroll et al. (2017) caution that there is 

a wide disparity between results 

obtained in field and laboratory settings. 

In experimental settings, changes were 

observed only when animals were 

housed in enclosed tanks and many 

were exposed to prolonged bouts of 

continuous, pure tones. We would not 

expect similar results in open marine 

conditions. It is unlikely that noises 

generated by survey activities will have 

any lasting effect on sea otter prey given 

the short-term duration of sounds 

produced by each component of the 

proposed work. 

Potential Impacts on Subsistence Uses 

The proposed activities will occur 

near marine subsistence harvest areas 

used by Alaska Natives from the villages 

of Pelican, Sitka, and Port Alexander. 

Between 1989 and 2019, approximately 

5,617 sea otters were harvested from 

these villages, averaging 187 per year 

(although numbers from 2019 are 

preliminary). The large majority (95 

percent) were taken by hunters based in 

Sitka. However, harvest activity takes 

place in coves where the sounds 

produced by survey equipment will not 

harass sea otters. 

The proposed project area will not 

occur in inshore waters and, therefore, 

will avoid significant overlap with 

subsistence harvest areas. NSF/L–DEO’s 

activities will not preclude access to 

hunting areas or interfere in any way 

with individuals wishing to hunt. NSF/ 

L–DEO will coordinate with Native 

villages and Tribal organizations to 

identify and avoid potential conflicts. If 

any conflicts are identified, NSF/L–DEO 

will develop a Plan of Cooperation 

(POC) specifying the particular steps 

necessary to minimize any effects the 

project may have on subsistence 

harvest. 


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Mitigation and Monitoring 

If an IHA for the NSF/L–DEO project 

is issued, it must specify means for 

affecting the least practicable adverse 

impact on sea otters and their habitat, 

paying particular attention to rookeries, 

mating grounds, and areas of similar 

significance and the availability of sea 

otters for subsistence uses by coastaldwelling Alaska Natives. 

In evaluating what mitigation 

measures are appropriate to ensure the 

least practicable adverse impact on 

species or stocks and their habitat, as 

well as subsistence uses, we considered 

the manner and degree to which the 

successful implementation of the 

measures are expected to achieve this 

goal. We considered the nature of the 

potential adverse impact being 

mitigated (likelihood, scope, range), the 

likelihood that the measures will be 

effective if implemented, and the 

likelihood of effective implementation. 

We also considered the practicability of 

the measures for applicant 

implementation (e.g., cost, impact on 

operations). 

To reduce the potential for 

disturbance from acoustic stimuli 

associated with the activities, the 

applicants have proposed mitigation 

measures including, but not limited to, 

the following: 

• Development of a marine mammal 

monitoring and mitigation plan; 

• Establishment of shutdown and 

monitoring zones; 

• Visual mitigation monitoring by 

designated Protected Species Observers 

(PSO); 

• Site clearance before startup; 

• Soft-start procedures; 

• Shutdown procedures; and 

• Vessel strike avoidance measures. 

These measures are further specified 

under Proposed Authorization, part B. 

Avoidance and Minimization. The 

Service has not identified any 

additional mitigation or monitoring 

measures not already incorporated into 

NSF’s request that are practicable and 

would further reduce potential impacts 

to sea otters and their habitat. 

Estimated Incidental Take 

Characterizing Take by Level B 

Harassment 

In the previous section, we discussed 

the components of the project activities 

that have the potential to affect sea 

otters. Here, we describe and categorize 

the physiological and behavioral effects 

that can be expected based on 

documented responses to human 

activities observed during sea otter 

studies. We also discuss how these 

behaviors are characterized under the 

MMPA. 

As we described in Evidence from Sea 

Otter Studies, an individual sea otter’s 

reaction to human activity will depend 

on the otter’s prior exposure to the 

activity, the potential benefit that may 

be realized by the individual from its 

current location, its physiological status, 

or other intrinsic factors. The location, 

timing, frequency, intensity, and 

duration of the encounter are among the 

external factors that will also influence 

the animal’s response. Intermediate 

reactions that disrupt biologically 

significant behaviors are considered 

Level B harassment under the MMPA. 

The Service has identified the following 

sea otter behaviors as indicating 

possible Level B take: 

• Swimming away at a fast pace on 

belly (i.e., porpoising); 

• Repeatedly raising the head 

vertically above the water to get a better 

view (spyhopping) while apparently 

agitated or while swimming away; 

• In the case of a pup, repeatedly 

spyhopping while hiding behind and 

holding onto its mother’s head; 

• Abandoning prey or feeding area; 

• Ceasing to nurse and/or rest 

(applies to dependent pups); 

• Ceasing to rest (applies to 

independent animals); 

• Ceasing to use movement corridors; 

• Ceasing mating behaviors; 

• Shifting/jostling/agitation in a raft 

so that the raft disperses; 

• Sudden diving of an entire raft; or 

• Flushing animals off a haulout. 

This list is not meant to encompass all 

possible behaviors; other situations may 

also indicate Level B take. 

Reactions capable of causing injury 

are characterized as Level A harassment 

events. The proposed action is not 

anticipated to result in Level A 

harassment due to exposure of otters to 

noise capable of causing PTS. However, 

it is also important to note that, 

depending on the duration and severity 

of the above-described Level B 

behaviors, such responses could 

constitute take by Level A harassment. 

For example, while a single flushing 

event would likely indicate Level B 

harassment, repeatedly flushing sea 

otters from a haulout may constitute 

Level A harassment. 

Calculating Take 

We assumed all animals exposed to 

underwater sound levels that meet the 

acoustic exposure criteria shown in 

Table 1 will experience, at a minimum, 

take by Level B harassment due to 

exposure to underwater noise. To 

estimate the number of otters that may 

be exposed to these sound levels, we 

worked closely with the applicant to 

create spatially explicit zones of 

ensonification around the proposed 

survey transects based on expected 

sound source levels and attenuation 

models. We determined the number of 

otters present in the ensonification 

zones using density information 

generated by Tinker et al. (2019) for the 

subgroups that comprise the Southeast 

Alaska stock. 

Zones of Level A and Level B 

ensonification were created using the 

proposed R/V Langseth transects along 

the Southeast Alaskan coast. We 

developed sound level isopleths 

through acoustic modeling by NSF/L– 

DEO for deep water and an analysis of 

empirical data collected in a 2012 

survey by the R/V Langseth along the 

Cascadia Margin in coastal Washington 

(Crone et al. 2014) for intermediate and 

shallow waters. The 2012 survey in 

Cascadia was conducted using a 4-string 

0.11-m3 (6,600-in3) airgun array at a tow 

depth of 9 m (29.5 ft), while the 

proposed activities in Southeast Alaska 

will use a 0.11-m3 (6,600-in3) airgun 

array at a tow depth of 12 m (39 ft). To 

account for this difference, the applicant 

used a scaling factor (see the application 

available as described under ADDRESSES

for details). The largest resulting Level 

A isopleth calculated from the NSF/L– 

DEO modeling (where sound levels will 

be greater than 232 dB peak) 

encompassed areas up to 10.6 m (34.7 

ft) from the sound source. The Level B 

isopleth (where sound levels will be 

between 160–231 dB) was based on 

empirical data and encompassed areas 

up to 12.65 km (7.9 mi) from the sound 

source when the R/V Langseth was in 

shallow water (<100 m or 328 ft ocean 

depth) and up to 9.2 km (5.7 mi) when 

the vessel was in intermediate depths 

(100–1,000 m or 328–3,280 ft ocean 

depth). 

The Level A and Level B isopleths 

were then used to create spatially 

explicit ensonification zones 

surrounding the proposed project 

transects using ArcGIS Pro (2018). Using 

the proximity toolset in ArcGIS Pro, we 

created a buffer with a 45-m (148-ft) 

width around the proposed project 

transects to account for the Level A 

ensonified area on either side of the 24 

m-wide (79 ft-wide) airgun array. To 

determine the Level B ensonified area, 

points were first placed along the 

proposed project transects every 500 m 

(0.3 mi). We then used bathymetry data 

to determine ocean depth at each point 

along the transect. We placed a 12.65- 

km (7.9-mi) buffer around points in 

water less than 100 m (328 ft) deep, and 

a 9.2-km (5.7-mi) buffer around points 

in water 100–1,000 m (328–3,280 ft) 


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deep. The resulting ocean depthinformed ensonification zone was then 

modified to remove ‘‘land shadows’’ 

(marine areas behind land features). To 

do this, we created lines representing 

ensonification that radiated from each 

point along the proposed project 

transects. Lines were then clipped with 

a landform shapefile to identify areas 

where underwater sound will be 

absorbed by land features. 

As we described in Description of 

Marine Mammals in the Specified Area, 

sea otters are overwhelmingly observed 

(95 percent) within the 40-m (131-ft) 

depth contour, although they can be 

found in areas with deeper water. Thus, 

high-density sea otter habitat was 

delineated by the 40-m (131-ft) depth 

contour, and low-density otter habitat 

was between the 40-m and 100-m (131- 

ft to 328-ft) depth contours. Habitat was 

further divided into subregions 

established by Tinker et al. (2019) as 

densities of otters in these subregions 

differed. Otter densities for the affected 

subregions were determined using 2012 

abundance estimates generated using 

the Bayesian hierarchical model 

developed by Tinker et al. (2019). 

Abundance estimates are traditionally 

generated using aerial survey data from 

high-density habitat (<40 m or 131 ft in 

depth). To calculate the density of otters 

in low-density habitat (40–100 m or 

131–328 ft ocean depth), we multiplied 

the density of the adjacent high-density 

habitat by 0.05. The resulting density 

estimate accounts for the five percent of 

otters found in low-density areas. 

The Level A ensonification zone did 

not overlap with either high- or lowdensity habitat areas. To determine the 

amount (km2) of Level B ensonified 

habitat in each subregion, the high- and 

low-density habitat shapefiles were 

clipped using the Level B ensonification 

shapefiles in ArcGIS Pro. The area 

impacted in each subregion was 

multiplied by the estimated otter 

density in that region to determine the 

number of otters that will experience 

Level B sound levels (Table 2). The total 

number of takes was predicted by 

estimating the projected days of activity 

in each subregion using survey start 

points supplied by the applicant. In 

several areas, the length and direction of 

the proposed survey transects make it 

highly unlikely that impacts will last 

only one day. In these instances, we 

estimated two days of disturbance, and 

thus two takes for each otter. 

TABLE 2—ESTIMATED NUMBER OF OTTERS ENSONIFIED BY SOUND LEVELS GREATER THAN 160 dB DUE TO THE

PROPOSED ACTIVITIES

[Level B take was calculated by multiplying the area ensonified in each subregion by that subregion’s modeled sea otter density, then multiplying 

by the projected days of ensonification] 

Subreg. Habitat type Density 

(otters/km2) 

Area 

impacted 

(km2) 

Estimated 

take/day 

Projected 

days of 

take 

Estimated 

survey 

total takes 

N06 ............................ High (<40 m) ............................................... 0.778 4.66 4 1 4 

S05 ............................. High (<40 m) ............................................... 1.333 8.74 12 2 24 

S12 ............................. High (<40 m) ............................................... 0.1748 2.56 1 2 2 

N06 ............................ Low (40–100 m) .......................................... 0.034 15.69 1 1 1 

S01 ............................. Low (40–100 m) .......................................... 0.084 42.31 4 2 8 

S05 ............................. Low (40–100 m) .......................................... 0.123 31.32 4 2 8 

S12 ............................. Low (40–100 m) .......................................... 0.0092 647.62 1 2 2 

Total .................... ...................................................................... ........................ .................... 27 .................... 49 

Current Stock 

Total.

...................................................................... 25,584 .................... .................... .................... ....................

Percentage 

of Stock.

...................................................................... ........................ .................... 0.001 .................... ....................

Critical Assumptions 

We estimate 49 takes of 27 sea otters 

by Level B harassment will occur due to 

NSF/L–DEO’s proposed high-energy 

seismic surveys. In order to conduct this 

analysis and estimate the potential 

amount of Level B take, several critical 

assumptions were made. 

Otter density was calculated using a 

Bayesian hierarchical model created by 

Tinker et al. (2019), which includes 

assumptions that can be found in the 

original publication. The most recently 

available density estimates and those 

used for our analysis were for the year 

2012. Low-density otter populations 

exhibit a growth rate that is typically 

directly related to resource availability, 

with growth rates slowing as the 

populations approach carrying capacity 

(Estes 1990). The populations in 

Southeast Alaska vary in their densities 

and estimated carrying capacities 

(Tinker et al. 2019), making it difficult 

to predict current density values. Thus, 

we relied on 2012 density estimates to 

calculate projected take. One subregion 

within the impact area, S12, was not 

included in the Tinker et al. (2019) 

published densities. To calculate otter 

density in this subregion, we used the 

2012 aerial survey data that served as 

the model’s primary input. Thus, the 

S12 density estimate does not benefit 

from the additional information 

included in the Bayesian model 

provided by Tinker et al. (2019). 

Estimation of ensonification zones 

used sound attenuation models that 

focused on absorption and dispersion 

rather than reflection and refraction. 

Our models assumed that points of land 

intercepting high-level noise will 

effectively attenuate sound levels above 

160 dB, and sea otters in areas behind 

those land features (in land shadows) 

will be exposed to sound less than 160 

dB. This assumption is adequate for this 

analysis given the offshore location of 

the survey transects. 

Finally, we estimated the repeated 

take of a portion of the otters affected by 

the proposed action due to the presence 

of the R/V Langseth for more than one 

day. We assume, due to the proposed 

survey transects, start points, and speed 

of the R/V Langseth, that otters within 

subregions S01, S05, and S12 will be 

ensonified for two days each. The 

applicant has listed a number of 

potential yet unanticipated reasons the 

R/V Langseth may remain in one area 

for an extended period of time, 

including poor data quality, inclement 

weather, or mechanical issues with the 

research vessel and/or equipment. 

However, except for the case of a 

reshoot due to poor data quality, the 

vessel’s airgun array (i.e., the source of 


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take) will not be operational during 

extended delays of operations. 

We estimate 49 instances of take by 

Level B harassment of 27 northern sea 

otters from the Southeast Alaska stock 

due to behavioral responses or TTS 

associated with noise exposure. These 

levels represent a small proportion of 

the most recent stock abundance 

estimate for the Southeast Alaska stock. 

Take of 27 otters is less than one percent 

of the best available estimate of the 

current population size of 25,584 

animals in the Southeast Alaska stock 

(Tinker et al. 2019) 

(27÷25,584=0.00105). Although an 

estimated 49 instances of take of 27 

otters by Level B harassment are 

possible, most events are unlikely to 

have significant consequences for the 

health, reproduction, or survival of 

affected animals. 

Sea otters exposed to sound projectproduced sounds are likely to respond 

with temporary behavioral modification 

or displacement. Project activities could 

temporarily interrupt the feeding, 

resting, and movement of sea otters. 

Because activities will occur during a 

limited amount of time and in a 

localized region, the impacts associated 

with the project are likewise temporary 

and localized. The anticipated effects 

are primarily short-term behavioral 

reactions and displacement of sea otters 

near active operations. 

Sea otters that encounter the specified 

activity may exert more energy than 

they would otherwise due to temporary 

cessation of feeding, increased 

vigilance, and retreat from the project 

area. We expect that affected sea otters 

will tolerate this exertion without 

measurable effects on health or 

reproduction. Most of the anticipated 

takes will be due to short-term Level B 

harassment in the form of TTS, startling 

reactions, or temporary displacement. 

Chronic exposure to sound levels that 

cause TTS may lead to PTS (which 

would constitute Level A injury). While 

more research into the relationship 

between chronic noise exposure and 

PTS is needed (Finneran 2015), it is 

likely that the transition from temporary 

effects to permanent cellular damage 

occurs over weeks, months, or years 

(Southall et al 2019). 

With the adoption of the measures 

proposed in NSF/L–DEO’s application 

and required by this proposed IHA, 

estimated take was reduced. 

Findings 

Small Numbers 

For small numbers analyses, the 

statute and legislative history do not 

expressly require a specific type of 

numerical analysis, leaving the 

determination of ‘‘small’’ to the agency’s 

discretion. In this case, we propose a 

finding that the NSF/L–DEO project 

may result in approximately 49 

incidental takes of 27 otters from the 

Southeast Alaska stock. This represents 

less than one percent of the estimated 

stock. Predicted levels of take were 

determined based on estimated density 

of sea otters in the project area and an 

ensonification zone developed using 

empirical evidence from a similar 

geographic area and corrected for the 

methodology proposed by NSF/L–DEO 

for this project. Based on these numbers, 

we propose a finding that the NSF/L– 

DEO project will take only a small 

number of animals. 

Negligible Impact 

We propose a finding that any 

incidental take by harassment resulting 

from the proposed project cannot be 

reasonably expected to, and is not 

reasonably likely to, adversely affect the 

sea otter through effects on annual rates 

of recruitment or survival and will, 

therefore, have no more than a 

negligible impact on the Southeast 

Alaska stock of northern sea otters. In 

making this finding, we considered the 

best available scientific information, 

including: The biological and behavioral 

characteristics of the species, the most 

recent information on species 

distribution and abundance within the 

area of the specified activities, the 

current and expected future status of the 

stock (including existing and 

foreseeable human and natural 

stressors), the potential sources of 

disturbance caused by the project, and 

the potential responses of marine 

mammals to this disturbance. In 

addition, we reviewed applicant 

provided materials, information in our 

files and datasets, published reference 

materials, and species experts. 

Sea otters are likely to respond to 

proposed activities with temporary 

behavioral modification or 

displacement. These reactions are 

unlikely to have consequences for the 

long-term health, reproduction, or 

survival of affected animals. Most 

animals will respond to disturbance by 

moving away from the source, which 

may cause temporary interruption of 

foraging, resting, or other natural 

behaviors. Affected animals are 

expected to resume normal behaviors 

soon after exposure with no lasting 

consequences. Twenty-one otters are 

estimated to be exposed to seismic noise 

for two days and thus, will have 

repeated exposure. However, permanent 

(i.e., Level A) injury due to chronic 

sound exposure is estimated to occur at 

the scale of weeks, months, or years 

(Southall et al. 2019). Some animals 

may exhibit more severe responses 

typical of Level B harassment, such as 

fleeing, ceasing feeding, or flushing 

from a haul-out. These responses could 

have temporary, yet significant, 

biological impacts for affected 

individuals but are unlikely to result in 

measurable changes in survival or 

reproduction. 

The total number of animals affected 

and severity of impact is not sufficient 

to change the current population 

dynamics at the stock scale. Although 

the specified activities may result in 

approximately 49 incidental takes of 27 

otters from the Southeast Alaska stock, 

we do not expect this level of 

harassment to affect annual rates of 

recruitment or survival or result in 

adverse effects on the stock. 

Our proposed finding of negligible 

impact applies to incidental take 

associated with the proposed activities 

as mitigated by the avoidance and 

minimization measures identified in 

NSF/L–DEO’s mitigation and 

monitoring plan. These mitigation 

measures are designed to minimize 

interactions with and impacts to sea 

otters. These measures and the 

monitoring and reporting procedures are 

required for the validity of our finding 

and are a necessary component of the 

proposed IHA. For these reasons, we 

propose a finding that the 2021 NSF/L– 

DEO project will have a negligible 

impact on the Southeast Alaska stock of 

northern sea otters. 

Impact on Subsistence 

We propose a finding that NSF/L– 

DEO’s anticipated harassment will not 

have an unmitigable adverse impact on 

the availability of the Southeast Alaska 

stock of northern sea otters for taking for 

subsistence uses. In making this finding, 

we considered the timing and location 

of the proposed activities and the timing 

and location of subsistence harvest 

activities in the area of the proposed 

project. We also considered the 

applicant’s consultation with 

subsistence communities, proposed 

measures for avoiding impacts to 

subsistence harvest, and commitment to 

development of a POC, should any 

concerns be identified. 

Required Determinations 

National Environmental Policy Act 

(NEPA) 

Per the National Environmental 

Policy Act (NEPA; 42 U.S.C. 4321, et 

seq.), the Service must evaluate the 

effects of the proposed action on the 

human environment. We plan to adopt 


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NSF’s environmental assessment (EA), 

as we have preliminarily concluded 

that, as written, the draft EA contains 

adequate information analyzing the 

effects on the human environment of 

issuing the IHA. NSF’s EA is available 

at https://www.nsf.gov/geo/oce/ 

envcomp/. If the Service determines that 

impacts from issuing the IHA would not 

significantly affect the human 

environment, we may prepare a Finding 

of No Significant Impact that would 

conclude the Service’s NEPA process. 

We will review all comments 

submitted in response to this notice as 

indicated above in DATES and 

ADDRESSES prior to concluding our 

NEPA process or making a final 

decision on the IHA. 

Endangered Species Act (ESA) 

Under the ESA, all Federal agencies 

are required to ensure the actions they 

authorize are not likely to jeopardize the 

continued existence of any threatened 

or endangered species or result in 

destruction or adverse modification of 

critical habitat. The proposed activities 

will occur entirely within the range of 

the Southeast Alaska stock of the 

northern sea otter, which is not listed as 

threatened or endangered under the 

ESA. The measures included in the 

proposed IHA will not affect other listed 

species or designated critical habitat. 

Government-to-Government 

Coordination 

It is our responsibility to 

communicate and work directly on a 

Government-to-Government basis with 

federally recognized Tribes in 

developing programs for healthy 

ecosystems. We are also required to 

consult with Alaska Native 

Corporations. We seek their full and 

meaningful participation in evaluating 

and addressing conservation concerns 

for protected species. It is our goal to 

remain sensitive to Alaska Native 

culture and to make information 

available to Alaska Natives. Our efforts 

are guided by the following policies and 

directives: 

(1) The Native American Policy of the 

Service (January 20, 2016); 

(2) the Alaska Native Relations Policy 

(currently in draft form); 

(3) Executive Order 13175 (January 9, 

2000); 

(4) Department of the Interior 

Secretarial Orders 3206 (June 5, 1997), 

3225 (January 19, 2001), 3317 

(December 1, 2011), and 3342 (October 

21, 2016); and 

(5) the Department of the Interior’s 

policies on consultation with Tribes and 

with Alaska Native Corporations. 

We have evaluated possible effects of 

the proposed activities on federally 

recognized Alaska Native Tribes and 

organizations. Through the IHA process 

identified in the MMPA, the applicant 

has presented a communication process, 

culminating in a POC if needed, with 

the Native organizations and 

communities most likely to be affected 

by their work. NSF/L–DEO has engaged 

these groups in informational meetings. 

We invite continued discussion, either 

about the project and its impacts or 

about our coordination and information 

exchange throughout the IHA/POC 

process. 

Proposed Authorization 

We propose to authorize up to 49 

incidental takes of 27 Northern sea 

otters from the Southeast Alaska stock. 

We authorize take limited to disruption 

of behavioral patterns that may be 

caused by geophysical surveys and 

support activities conducted by NSF/L– 

DEO in Southeast Alaska, from July 1 to 

August 31, 2021. We anticipate no take 

by injury or death to northern sea otters 

resulting from these surveys. 

A. General Conditions for Issuance of 

the Proposed IHA 

1. The taking of Northern sea otters 

from the Southeast Alaska stock 

whenever the required conditions, 

mitigation, monitoring, and reporting 

measures are not fully implemented as 

required by the IHA will be prohibited. 

Failure to follow measures specified 

may result in the suspension or 

revocation of the IHA. 

2. If take exceeds the level or type 

identified in the proposed authorization 

(e.g., greater than 49 incidents of 

incidental take of 27 otters by Level B 

harassment), the IHA will be invalidated 

and the Service will reevaluate its 

findings. If project activities cause 

unauthorized take, such as any injury 

due to seismic noise, acute distress, or 

any indication of the separation of 

mother from pup, NSF/L–DEO must 

take the following actions: (i) Cease its 

activities immediately (or reduce 

activities to the minimum level 

necessary to maintain safety); (ii) report 

the details of the incident to the 

Service’s MMM within 48 hours; and 

(iii) suspend further activities until the 

Service has reviewed the circumstances, 

determined whether additional 

mitigation measures are necessary to 

avoid further unauthorized taking, and 

notified NSF/L–DEO that it may resume 

project activities. 

3. All operations managers and vessel 

operators must receive a copy of the 

IHA and maintain access to it for 

reference at all times during project 

work. These personnel must 

understand, be fully aware of, and be 

capable of implementing the conditions 

of the IHA at all times during project 

work. 

4. The IHA will apply to activities 

associated with the proposed project as 

described in this document and in NSF/ 

L–DEO’s amended application (LGL 

2020). Changes to the proposed project 

without prior authorization may 

invalidate the IHA. 

5. NSF/L–DEO’s IHA application will 

be approved and fully incorporated into 

the IHA, unless exceptions are 

specifically noted herein or in the final 

IHA. The application includes: 

• NSF/L–DEO’s original request for 

an IHA, dated December 19, 2019; 

• NSF/L–DEO’s response to requests 

for additional information from the 

Service, dated January 22, February 19, 

and February 26, 2020; and 

• A revised application, dated 

October 29, 2020. 

6. Operators will allow Service 

personnel or the Service’s designated 

representative to visit project work sites 

to monitor impacts to sea otters and 

subsistence uses of sea otters at any time 

throughout project activities so long as 

it is safe to do so. ‘‘Operators’’ are all 

personnel operating under the NSF/L– 

DEO’s authority, including all 

contractors and subcontractors. 

B. Avoidance and Minimization 

7. Seismic surveys must be conducted 

using equipment that generates the 

lowest practicable levels of underwater 

sound within the range of frequencies 

audible to sea otters. 

8. Vessels will not approach within 

100 m (328 ft) of individual sea otters 

or 500 m (0.3 mi) of rafts of otters. 

Operators will reduce vessel speed if a 

sea otter approaches or surfaces within 

100 m (328 ft) of a vessel. 

9. Vessels may not be operated in 

such a way as to separate members of 

a group of sea otters from other 

members of the group. 

10. All vessels must avoid areas of 

active or anticipated subsistence 

hunting for sea otters as determined 

through community consultations. 

C. Mitigation During Seismic Activities 

11. Designated trained and qualified 

PSOs must be employed to monitor for 

the presence of sea otters, initiate 

mitigation measures, and monitor, 

record, and report the effects of the 

activities on sea otters. NSF/L–DEO is 

responsible for providing training to 

PSOs to carry out mitigation and 

monitoring. 

12. NSF/L–DEO must establish 

mitigation zones for their 2D seismic 


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surveys, which generate underwater 

sound levels at or more than or 160 dB 

between 125 Hz and 38 kHz. Mitigation 

zones must include all in-water areas 

where work-related sound received by 

sea otters will match the levels and 

frequencies above. Mitigation zones will 

be designated as follows: 

• Exclusion Zones (EZ) will be 

established with the following 

minimum radii: 500 m (0.3 mi) from the 

source for the full seismic array and 100 

m (328 ft) for the single bolt airgun (655 

cm3 or 40 in3). 

• A Safety Zone (SZ) is an area larger 

than the EZ and will include all areas 

within which sea otters may be exposed 

to noise levels that will likely result in 

Level B take. 

• Both the EZ and SZ will be centered 

on the sound source (the seismic array). 

• The radius of the SZs are shown in 

Table 3 (as calculated based on 

modeling techniques described herein 

and in Appendix A of NSF/L–DEO’s 

application). 

TABLE 3—ESTIMATED RADIAL DISTANCES FROM THE SEISMIC SOUND SOURCE TO THE 160-dB ISOPLETH

[The area within the isopleth is designated as the Safety Zone (SZ)] 

Source and volume Water depth 

(m) 

Predicted 

distances 

(in m) 

to the 160 dB 

received 

sound level 

Single Bolt airgun, 40 in 3 ............................................................................................. >1,000 m ................................................... 1 431 

100–1,000 m ............................................. 2 647 

<100 m ...................................................... 3 1,041 

<1000 m .................................................... 1 6,733 

4 strings, 36 airguns, 6600 in 3 .................................................................................... 100–1,000m .............................................. 4 9,468 

<100m ....................................................... 4 12,650 

1 Distance is based on L–DEO model results. 

2 Distance is based on L–DEO model results with a 1.5 × correction factor between deep and intermediate water depths. 3 Distance is based on empirically derived measurements in the GOM with scaling applied to account for differences in tow depth. 

4Based on empirical data from Crone et al. (2014); see Appendix A of the NSF/L–2012;DEO IHA application for details. 

13. PSOs must conduct visual 

monitoring of the entire EZ and the 

visible SZ continuously during all 

seismic work occurring in daylight 

hours. 

14. Prior to seismic work, a ‘‘rampup’’ procedure must be used to increase 

the levels of underwater sound at a 

gradual rate. 

• A ramp-up will be used at the 

initial start of airgun operations and 

prior to restarting after any period 

greater than 30 minutes (min) without 

airgun operations, including a powerdown or shutdown event. 

• Visual monitoring must begin at 

least 30 min prior to and continue 

throughout ramp-up efforts. 

• During geophysical work, the 

number and total volume of airguns will 

be increased incrementally until the full 

volume is achieved. 

• The rate of ramp-up will be no more 

than 6 dB per 5-min period. Ramp-up 

will begin with the smallest gun in the 

array that is being used for all airgun 

array configurations. During the rampup, the applicable mitigation zones 

(based on type of airgun and sound 

levels produced) must be maintained. 

• It will not be permissible to rampup the full array from a complete 

shutdown in thick fog or at other times 

when the outer part of the EZ is not 

visible. 

• Ramp-up of the airguns will not be 

initiated if a sea otter is sighted within 

the EZ at any time. 

• If sea otters are observed during a 

ramp-up effort or prior to startup, a PSO 

must record the observation and 

monitor the animal’s position until it 

moves out of visual range. Seismic work 

may commence if, after a full and 

gradual effort to ramp up the 

underwater sound level, the sea otter is 

outside of the EZ and does not show 

signs of visible distress (for example, 

vocalizing, repeatedly spy-hopping, or 

fleeing). 

15. The following actions must be 

taken in response to sea otters in 

mitigation zones: 

• Seismic work will be shut down 

completely if a sea otter is observed 

within the 500-m (0.3-mi) EZ for the full 

array or the 100-m (328-ft) EZ for the 40- 

cui array. 

• When sea otters are observed in 

visible distress (for example, vocalizing, 

repeatedly spy-hopping, or fleeing), 

seismic work must be immediately shut 

down or powered down to reduce noise 

exposure. 

• The shutdown procedure will be 

accomplished within several seconds of 

the determination that a sea otter is in 

the applicable EZ or as soon as 

practicable considering worker safety 

and equipment integrity. 

• Following a shutdown, seismic 

work will not resume until the sea otter 

has cleared the EZ. The animal will be 

considered to have cleared the EZ if it 

is visually observed to have left the EZ 

or has not been seen within the EZ for 

30 minutes or longer. 

• Any shutdown due to sea otters 

sighted within the EZ must be followed 

by a 30-minute all-clear period and then 

a standard full ramp-up. 

• Any shutdown for other reasons 

resulting in the cessation of seismic 

work for a period greater than 30 

minutes must also be followed by full 

ramp-up procedures. 

16. Operators may reduce power to 

seismic equipment as an alternative to 

a shutdown to prevent a sea otter from 

entering the EZ. A power-down 

procedure involves reducing the volume 

of underwater sound generated. Vessel 

speed or course may be altered to 

achieve the same task. 

• Whenever a sea otter is detected 

outside the EZ and, based on its 

position and motion relative to the 

seismic work, appears likely to enter the 

EZ but has not yet done so, the operator 

may power down to reduce high-level 

noise exposure. 

• When a sea otter is detected in the 

SZ, an operator may choose to power 

down when practicable to reduce Level 

B take, but is not required to do so. 

• During a power-down, the number 

of airguns in use will be reduced to a 

single mitigation airgun (airgun of small 

volume such as the 655-cm3 (40-in3) 

gun), such that the EZ is reduced, 

making the sea otters unlikely to enter 

the EZ. 

• After a power-down, noisegenerating work will not resume until 

the sea otter has cleared the EZ for the 

full airgun array. The animal will be 


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Federal Register / Vol. 86, No. 109 / Wednesday, June 9, 2021 / Notices 30625 

considered to have cleared the EZ if it 

is visually observed to have left the EZ 

and has not been seen within the zone 

for 30 minutes. 

17. Visual monitoring must continue 

for 30 minutes after the use of the 

acoustic source ceases or the sun sets, 

whichever is later. 

D. Monitoring 

18. Operators shall work with PSOs to 

apply mitigation measures and shall 

recognize the authority of PSOs up to 

and including stopping work, except 

where doing so poses a significant safety 

risk to vessels and personnel. 

19. Duties of PSOs include watching 

for and identifying sea otters, recording 

observation details, documenting 

presence in any applicable monitoring 

zone, identifying and documenting 

potential harassment, and working with 

vessel operators to implement all 

appropriate mitigation measures. 

20. A sufficient number of PSOs will 

be onboard to meet the following 

criteria: 100 percent monitoring 

coverage during all daytime periods of 

seismic activity; a maximum of four 

consecutive hours on watch per PSO; a 

maximum of approximately 12 hours on 

watch per day per PSO; and at least one 

observer each on the source vessel and 

support vessel. 

21. All PSOs will complete a training 

course designed to familiarize 

individuals with monitoring and data 

collection procedures. A field crew 

leader with prior experience as a marine 

mammal observer will supervise the 

PSO team. New or inexperienced PSOs 

will be paired with experienced PSOs so 

that the quality of marine mammal 

observations and data recording is kept 

consistent. Resumes for candidate PSOs 

will be made available for the Service to 

review. 

22. Observers will be provided with 

reticule binoculars (10×42), big-eye 

binoculars or spotting scopes (30×), 

inclinometers, and range finders. Field 

guides, instructional handbooks, maps 

and a contact list will also be made 

available. 

E. Measures To Reduce Impacts to 

Subsistence Users 

23. Prior to conducting the work, 

NSF/L–DEO will take the following 

steps to reduce potential effects on 

subsistence harvest of sea otters: 

• Avoid work in areas of known sea 

otter subsistence harvest; 

• Discuss the planned activities with 

subsistence stakeholders including 

Southeast Alaska villages and 

traditional councils; 

• Identify and work to resolve 

concerns of stakeholders regarding the 

project’s effects on subsistence hunting 

of sea otters; and 

• If any concerns remain, develop a 

POC in consultation with the Service 

and subsistence stakeholders to address 

these concerns. 

F. Reporting Requirements 

24. NSF/L–DEO must notify the 

Service at least 48 hours prior to 

commencement of activities. 

25. Reports will be submitted to the 

Service’s MMM weekly during project 

activities. The reports will summarize 

project work and monitoring efforts. 

26. A final report will be submitted to 

the Service’s MMM within 90 days after 

completion of work or expiration of the 

IHA. It will summarize all monitoring 

efforts and observations, describe all 

project activities, and discuss any 

additional work yet to be done. Factors 

influencing visibility and detectability 

of marine mammals (e.g., sea state, 

number of observers, fog, and glare) will 

be discussed. The report will describe 

changes in sea otter behavior resulting 

from project activities and any specific 

behaviors of interest. Sea otter 

observation records will be provided in 

the form of electronic database or 

spreadsheet files. The report will assess 

any effects NSF/–DEO’s operations may 

have had on the availability of sea otters 

for subsistence harvest and if 

applicable, evaluate the effectiveness of 

the POC for preventing impacts to 

subsistence users of sea otters. 

27. Injured, dead, or distressed sea 

otters that are not associated with 

project activities (e.g., animals found 

outside the project area, previously 

wounded animals, or carcasses with 

moderate to advanced decomposition or 

scavenger damage) must be reported to 

the Service within 24 hours of 

discovery. Photographs, video, location 

information, or any other available 

documentation shall be provided to the 

Service. 

28. All reports shall be submitted by 

email to fw7_mmm_reports@fws.gov. 

29. NSF/L–DEO must notify the 

Service upon project completion or end 

of the work season. 

Request for Public Comments 

If you wish to comment on this 

proposed authorization, the 

applicability of NSF’s draft EA to the 

proposed action, or the proposed 

adoption of NSF’s EA, you may submit 

your comments by any of the methods 

described in ADDRESSES. Please identify 

if you are commenting on the proposed 

authorization, draft EA, or both, make 

your comments as specific as possible, 

confine them to issues pertinent to the 

proposed authorization or draft EA, and 

explain the reason for any changes you 

recommend. Where possible, your 

comments should reference the specific 

section or paragraph that you are 

addressing. The Service will consider 

all comments that are received before 

the close of the comment period (see 

DATES). 

Comments, including names and 

street addresses of respondents, will 

become part of the administrative record 

for this proposal. Before including your 

address, telephone number, email 

address, or other personal identifying 

information in your comment, be 

advised that your entire comment, 

including your personal identifying 

information, may be made publicly 

available at any time. While you can ask 

us in your comments to withhold from 

public review your personal identifying 

information, we cannot guarantee that 

we will be able to do so. 

Gregory Siekaniec, 

Regional Director, Alaska Region. 

[FR Doc. 2021–12134 Filed 6–8–21; 8:45 am] 

BILLING CODE 4333–15–P 

DEPARTMENT OF THE INTERIOR 

Geological Survey 

[GX21EE000101100] 

Public Meeting of the National 

Geospatial Advisory Committee 

AGENCY: U.S. Geological Survey, 

Interior. 

ACTION: Notice of public meeting. 

SUMMARY: In accordance with the 

Federal Advisory Committee Act of 

1972, the U.S. Geological Survey 

(USGS) is publishing this notice to 

announce that a Federal Advisory 

Committee meeting of the National 

Geospatial Advisory Committee (NGAC) 

will take place. 

DATES: The meeting will be held as a 

webinar on Tuesday, June 29, 2021 from 

1:00 p.m. to 5:00 p.m., and on 

Wednesday, June 30, 2021 from 1:00 

p.m. to 5:00 p.m. (Eastern Daylight 

Time). 

ADDRESSES: The meeting will be held 

on-line and via teleconference. 

Instructions for accessing the meeting 

will be posted at www.fgdc.gov/ngac. 

Comments can be sent to Ms. Dionne 

Duncan-Hughes, Group Federal Officer 

by email to gs-faca-mail@usgs.gov. 

FOR FURTHER INFORMATION CONTACT: Mr. 

John Mahoney, Federal Geographic Data 

Committee (FGDC), USGS, 909 First 

Avenue, Suite 800, Seattle, WA 98104; 

by email at jmahoney@usgs.gov; or by 

telephone at (206) 220–4621. 


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