29090 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

[RTID 0648–XA144] 

Takes of Marine Mammals Incidental to 

Specified Activities; Taking Marine 

Mammals Incidental to a Marine 

Geophysical Survey in the Northeast 

Pacific Ocean 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Notice; issuance of an incidental 

harassment authorization. 

SUMMARY: In accordance with the 

regulations implementing the Marine 

Mammal Protection Act (MMPA) as 

amended, notification is hereby given 

that NMFS has issued an incidental 

harassment authorization (IHA) to 

Lamont-Doherty Earth Observatory of 

Columbia University (L–DEO) to 

incidentally harass, by Level A and 

Level B harassment, marine mammals 

during a marine geophysical survey in 

the northeast Pacific Ocean. 

DATES: This Authorization is effective 

from May 19, 2021 through May 18, 

2022. 

FOR FURTHER INFORMATION CONTACT: 

Amy Fowler, Office of Protected 

Resources, NMFS, (301) 427–8401. 

Electronic copies of the application and 

supporting documents, as well as a list 

of the references cited in this document, 

may be obtained online at: https://

www.fisheries.noaa.gov/permit/ 

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

of problems accessing these documents, 

please call the contact listed above. 

SUPPLEMENTARY INFORMATION: 

Background 

The MMPA prohibits the ‘‘take’’ of 

marine mammals, with certain 

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

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

seq.) direct the Secretary of Commerce 

(as delegated to NMFS) to allow, upon 

request, the incidental, but not 

intentional, taking of small numbers of 

marine mammals by U.S. citizens who 

engage in a specified activity (other than 

commercial fishing) within a specified 

geographical region if certain findings 

are made and either regulations are 

issued or, if the taking is limited to 

harassment, a notice of a proposed 

incidental take authorization may be 

provided to the public for review. 

Authorization for incidental takings 

shall be granted if NMFS finds that the 

taking will have a negligible impact on 

the species or stock(s) and will not have 

an unmitigable adverse impact on the 

availability of the species or stock(s) for 

taking for subsistence uses (where 

relevant). Further, NMFS must prescribe 

the permissible methods of taking and 

other ‘‘means of effecting the least 

practicable adverse impact’’ on the 

affected species or stocks and their 

habitat, paying particular attention to 

rookeries, mating grounds, and areas of 

similar significance, and on the 

availability of the species or stocks for 

taking for certain subsistence uses 

(referred to in shorthand as 

‘‘mitigation’’); and requirements 

pertaining to the mitigation, monitoring 

and reporting of the takings are set forth. 

Summary of Request 

On November 8, 2019, NMFS received 

a request from L–DEO for an IHA to take 

marine mammals incidental to a marine 

geophysical survey of the Cascadia 

Subduction Zone off the coasts of 

Washington, Oregon, and British 

Columbia, Canada. The application was 

deemed adequate and complete on 

March 6, 2020. L–DEO’s request is for 

take of small numbers of 31 species of 

marine mammals by Level A and Level 

B harassment. NMFS published a notice 

of proposed IHA for public review and 

comment on April 7, 2020 (85 FR 

19580). On May 29, 2020, L–DEO 

informed NMFS that the project had 

been delayed by one year and would 

begin in June 2021. 

Description of Proposed Activity 

Overview 

Researchers from L–DEO, Woods Hole 

Oceanographic Institution (WHOI), and 

the University of Texas at Austin 

Institute of Geophysics (UTIG), with 

funding from the National Science 

Foundation (NSF), and in collaboration 

with researchers from Dalhousie 

University and Simon Fraser University 

(SFU) plan to conduct a high-energy 

seismic survey from the Research Vessel 

(R/V) Marcus G Langseth (Langseth) in 

the northeast Pacific Ocean beginning in 

June 2021. The seismic survey will be 

conducted at the Cascadia Subduction 

Zone off the coasts of Oregon, 

Washington, and British Columbia, 

Canada. The proposed two-dimensional 

(2–D) seismic survey will occur within 

the Exclusive Economic Zones (EEZs) of 

Canada and the United States, including 

U.S. state waters and Canadian 

territorial waters. The survey will use a 

36-airgun towed array with a total 

discharge volume of ∼6,600 cubic inches 

(in3) as an acoustic source, acquiring 

return signals using both a towed 

streamer as well ocean bottom 

seismometers (OBSs) and ocean bottom 

nodes (OBNs). 

The planned study will use 2–D 

seismic surveying and OBSs and OBNs 

to investigate the Cascadia Subduction 

Zone and provide data necessary to 

illuminate the depth, geometry, and 

physical properties of the seismogenic 

portion and updip extent of the 

megathrust zone between the 

subducting Juan de Fuca plate and the 

overlying accretionary wedge/North 

American plate. These data will provide 

essential constraints for earthquake and 

tsunami hazard assessment in this 

heavily populated region of the Pacific 

Northwest. The primary objectives of 

the survey planned by researchers from 

L–DEO, WHOI, and UTIG is to 

characterize: (1) The deformation and 

topography of the incoming plate; (2) 

the depth, topography, and reflectivity 

of the megathrust; (3) sediment 

properties and amount of sediment 

subduction; and (4) the structure and 

evolution of the accretionary wedge, 

including geometry and reflectivity of 

fault networks, and how these 

properties vary along strike, spanning 

the full length of the margin and down 

dip across what may be the full width 

of the Cascadia Subduction Zone. 

Dates and Duration 

The survey is expected to last for 40 

days, with 37 days of seismic 

operations, 2 days of equipment 

deployment, and 1 day of transit. R/V 

Langseth will likely leave out of and 

return to port in Newport, Oregon, 

during June–July 2021. 

Specific Geographic Region 

The survey will occur within ∼42–51° 

N, ∼124–130° W. Planned survey 

tracklines are shown in Figure 1. Some 

deviation in actual track lines, including 

the order of survey operations, could be 

necessary for reasons such as science 

drivers, poor data quality, inclement 

weather, or mechanical issues with the 

research vessel and/or equipment. The 

survey will occur within the EEZs of the 

United States and Canada, as well as in 

U.S. state waters and Canadian 

territorial waters, ranging in depth 60– 

4400 meters (m). A maximum of 6,540 

kilometers (km) of transect lines will be 

surveyed. Most of the survey (69 

percent) will occur in deep water 

(>1,000 m), 28 percent will occur in 

intermediate water (100–1,000 m deep), 

and 3 percent will take place in shallow 

water <100 m deep. Approximately 3.6 

percent of the transect lines (234 km) 

will be undertaken in Canadian 

territorial waters (from 0–12 nautical 

miles (22.2 km) from shore), with most 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29091 

effort in intermediate water depths. 

NMFS cannot authorize the incidental 

take of marine mammals in the 

territorial seas of foreign nations, as the 

MMPA does not apply in those waters. 

However, NMFS has still calculated the 

level of incidental take in the entire 

activity area (including Canadian 

territorial waters) as part of the analysis 

supporting our determination under the 

MMPA that the activity will have a 

negligible impact on the affected 

species. 

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29092 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

Detailed Description of Specific Activity 

The procedures to be used for the 

planned survey will be similar to those 

used during previous seismic surveys by 

L–DEO and will use conventional 

seismic methodology. The surveys will 

involve one source vessel, R/V 

Langseth. R/V Langseth will deploy an 

array of 36 airguns as an energy source 

with a total volume of ∼6,600 in3. The 

array consists of 20 Bolt 1500LL airguns 

with volumes of 180 to 360 in3 and 16 

Bolt 1900LLX airguns with volumes of 

40 to 120 in3. The airgun array 

configuration is illustrated in Figure 2– 

11 of NSF and USGS’s Programmatic 

Environmental Impact Statement (PEIS; 

NSF–USGS, 2011). The vessel speed 

during seismic operations will be 

approximately 4.2 knots (∼7.8 km/hour) 

during the survey and the airgun array 

will be towed at a depth of 12 m. The 

receiving system will consist of one 15- 

km long hydrophone streamer, OBSs, 

and OBNs. R/V Oceanus, which is 

owned by NSF and operated by Oregon 

State University, will be used to deploy 

the OBSs and OBNs. As the airguns are 

towed along the survey lines, the 

hydrophone streamer will transfer the 

data to the on-board processing system, 

and the OBSs and OBNs will receive 

and store the returning acoustic signals 

internally for later analysis. 

Long 15-km-offset multichannel 

seismic (MCS) data will be acquired 

along numerous 2–D profiles oriented 

perpendicular to the margin and located 

to provide coverage in areas inferred to 

be rupture patches during past 

earthquakes and their boundary zones. 

The survey will also include several 

strike lines including one continuous 

line along the continental shelf centered 

roughly over gravity-inferred fore-arc 

basins to investigate possible 

segmentation near the down-dip limit of 

the seismogenic zone. The margin 

normal lines will extend ∼50 km 

seaward of the deformation front to 

image the region of subduction bend 

faulting in the incoming oceanic plate, 

and landward of the deformation front 

to as close to the shoreline as can be 

safely maneuvered. L–DEO plans to 

survey the southern transects off Oregon 

first, followed by the profiles off 

Washington and Vancouver Island, 

British Columbia. 

The OBSs will consist of short-period 

multi-component OBSs from the Ocean 

Bottom Seismometer Instrument Center 

(OBSIC) and a large-N array of OBNs 

from a commercial provider to record 

shots along ∼11 MCS marginperpendicular profiles. OBSs will be 

deployed at 10-km spacing along ∼10 

profiles from Vancouver Island to 

Oregon, and OBNs will be deployed at 

a 500-m spacing along a portion of three 

profiles off Oregon. Two OBS 

deployments will occur with a total of 

115 instrumented locations. 60 OBSs 

will be deployed to instrument seven 

profiles off Oregon, followed by a 

second deployment of 55 OBSs to 

instrument four profiles off Washington 

and Vancouver Island. The first 

deployment off Oregon will occur prior 

to the start of the planned survey, after 

which R/V Langseth will acquire data in 

the southern portion of the study area. 

R/V Oceanus will start recovering the 

OBSs from deployment 1, and then redeploy 55 OBSs off Washington and 

Vancouver Island, so that R/V Langseth 

can acquire data in the northern portion 

of the survey area. The OBSs have a 

height and diameter of ∼1 m, and an ∼80 

kilogram (kg) anchor. To retrieve OBSs, 

an acoustic release transponder (pinger) 

is used to interrogate the instrument at 

a frequency of 8–11 kilohertz (kHz), and 

a response is received at a frequency of 

11.5–13 kHz. The burn-wire release 

assembly is then activated, and the 

instrument is released to float to the 

surface from the anchor, which is not 

retrieved. 

A total of 350 OBNs will be deployed: 

179 nodes along one transect off 

northern Oregon, 107 nodes along a 

second transect off central Oregon, and 

64 nodes along a third transect off 

southern Oregon. The nodes are not 

connected to each other; each node is 

independent from each other, and there 

are no cables attached to them. Each 

node has internal batteries; all data is 

recorded and stored internally. The 

nodes weigh 21 kg in air (9.5 kg in 

water). As the OBNs are small (330 

millimeters (mm) × 289 mm × 115 mm), 

compact, not buoyant, and lack an 

anchor-release mechanism, they cannot 

be deployed by free-fall as with the 

OBSs. The nodes will be deployed and 

retrieved using a remotely operated 

vehicle (ROV); the ROV will be 

deployed from R/V Oceanus. OBNs will 

be deployed approximately 17 days 

prior to the start of the R/V Langseth 

cruise. The ROV will be fitted with a 

skid with capacity for 32 units, lowered 

to the seafloor, and towed at a speed of 

0.6 knots at 5–10 m above the seafloor 

between deployment sites. After the 32 

units are deployed, the ROV will be 

retrieved, the skid will be reloaded with 

another 32 units, and sent back to the 

seafloor for deployment, and so on. The 

ROV will recover the nodes 3 days after 

the completion of the R/V Langseth 

cruise. The nodes will be recovered one 

by one by a suction mechanism. Take of 

marine mammals is not expected to 

occur incidental to L–DEO’s use of 

OBSs and OBNs. 

In addition to the operations of the 

airgun array, a multibeam echosounder 

(MBES), a sub-bottom profiler (SBP), 

and an Acoustic Doppler Current 

Profiler (ADCP) will be operated from R/ 

V Langseth continuously during the 

seismic surveys, but not during transit 

to and from the survey area. All planned 

geophysical data acquisition activities 

will be conducted by L–DEO with onboard assistance by the scientists who 

have planned the studies. The vessel 

will be self-contained, and the crew will 

live aboard the vessel. Take of marine 

mammals is not expected to occur 

incidental to use of the MBES, SBP, or 

ADCP because they will be operated 

only during seismic acquisition, and it 

is assumed that, during simultaneous 

operations of the airgun array and the 

other sources, any marine mammals 

close enough to be affected by the 

MBES, SBP, and ADCP would already 

be affected by the airguns. However, 

whether or not the airguns are operating 

simultaneously with the other sources, 

given their characteristics (e.g., narrow 

downward-directed beam), marine 

mammals would experience no more 

than one or two brief ping exposures, if 

any exposure were to occur. Mitigation, 

monitoring, and reporting measures are 

described in detail later in this 

document (please see Mitigation and 

Monitoring and Reporting). 

Comments and Responses 

A notice of NMFS’s proposal to issue 

an IHA to L–DEO was published in the 

Federal Register on April 7, 2020 (85 FR 

19580). During the public comment 

period, NMFS received comment letters 

from the Marine Mammal Commission 

(Commission), Ecojustice (on behalf of 

the David Suzuki Foundation, Georgia 

Strait Alliance, Raincoast Conservation 

Foundation, and World Wildlife Fund 

Canada), Deep Green Wilderness, and a 

group of environmental nongovernmental organizations (ENGOs) 

including the Center for Biological 

Diversity (CBD), Natural Resources 

Defense Council, Orca Relief Citizens 

Alliance, Friends of the San Juans, 

Whale and Dolphin Conservation, 

Friends of the Earth, Oceana, and Orca 

Conservancy. NMFS has posted the 

comments online at: https://

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/incidentaltake-authorizations-research-and-otheractivities. Please see the letters for full 

details and rationale. A summary of the 

comments and our responses are 

provided here. 

Comment 1: Ecojustice requested 

NMFS deny L–DEO’s request for an IHA 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29093 

because the survey will affect Southern 

Resident killer whale critical habitat 

(e.g., Swiftsure and La Perouse Banks) 

designated in Canada under the 

Canadian Species at Risk Act (SARA). 

The commenter asserts that noise 

production in these areas will both 

harm or harass individuals and 

constitute destruction of a portion of 

Canadian critical habitat. 

Response: This comment is beyond 

the scope of NMFS’ proposed action, 

which is to authorize take of marine 

mammals incidental to the proposed 

survey. NMFS does not allow or deny 

the survey itself, and NMFS’ action of 

authorizing incidental take does not 

cause effects to critical habitat (in 

Canada or the U.S.). However, as part of 

their consultation with Canada’s 

Department of Fisheries and Oceans 

(DFO) under Canada’s SARA, L–DEO 

has removed all survey tracklines with 

associated ensonified areas that overlap 

with Canadian designated killer whale 

critical habitat at Swiftsure and La 

Perouse Bank (see Figure 1); therefore, 

the Canadian critical habitat will not be 

subject to destruction. 

Comment 2: Ecojustice asserts that the 

critically endangered status of Southern 

Resident killer whales means there is no 

acceptable level of take for the species. 

Similarly, the ENGOs recommended 

NMFS not issue any take authorization 

until it has effectively reduced the take 

of Southern Resident killer whales to 

zero, citing concern that behavioral 

disturbance can interfere with 

reproduction and survival due to lost 

foraging time. 

Response: NMFS disagrees that there 

is no acceptable level of take for 

Southern Resident killer whales, and 

the commenters have not demonstrated 

that any level of taking of Southern 

Resident killer whales would result in 

greater than a negligible impact on the 

stock. However, we do agree that 

additional effort to reduce impacts to 

Southern Resident killer whales is 

warranted to minimize to the extent 

practicable the amount of taking as well 

as the impact of taking that is 

authorized. In addition to removing 

tracklines within Canadian designated 

Southern Resident killer whale critical 

habitat at Swiftsure and La Perouse 

Banks (discussed above), L–DEO has 

removed and modified tracklines 

between Tillamook Head, Oregon and 

Barkley Sound, British Columbia, the 

area in which Southern Resident killer 

whales have the highest estimated 

densities (U.S. Navy 2019) and high-use 

foraging areas (NMFS 2019). The effect 

of these modifications to the survey 

plan is that, between these landmarks, 

the estimated Level B harassment 

ensonified area will not extend into 

water shallower than the 100-m depth 

contour. As a result, the total estimated 

take of Southern Resident killer whales 

has been reduced from 43 takes by Level 

B harassment in the proposed IHA (with 

an additional two takes within Canadian 

territorial waters, outside NMFS’ 

jurisdiction) to 10 takes by Level B 

harassment (plus one take by Level B 

harassment within Canadian territorial 

waters), which is less than the 

population of any pod in the Southern 

Resident stock. This estimated take 

represents either 10 individual Southern 

Resident killer whales taken by Level B 

harassment once over the course of the 

survey, or a smaller number of 

individuals taken multiple times (e.g., a 

single matriline of five animals taken by 

Level B harassment on two separate 

days). By avoiding surveying in the 

areas with highest expected Southern 

Resident killer whale presence and 

foraging rates, the likelihood of survey 

activities resulting in interference in 

feeding and migration that could result 

in lost feeding opportunities or 

necessitate additional energy 

expenditure to find other good foraging 

opportunities or migration routes is 

greatly reduced. Procedural mitigations 

that avoid the likelihood of injury, such 

as shutdown measures, also further 

reduce the likelihood of more severe 

behavioral responses. 

Comment 3: The ENGOs assert that 

NMFS inadequately considered the 

impacts of the proposed action on prey 

availability for Southern Resident killer 

whales, citing studies showing 

responses of fish to sound from seismic 

surveys. The ENGOs also state that 

NMFS must also consider the fitness of 

salmon being indirectly affected by the 

survey’s impacts on herring, a key prey 

species for Pacific salmon. 

Response: NMFS disagrees with the 

suggestion that we ignored effects to 

prey species. In fact, we considered 

relevant literature (including that cited 

by the ENGOs) in finding that the most 

likely impact of survey activity to prey 

species such as fish and invertebrates 

would be temporary avoidance of an 

area, with a rapid return to pre-survey 

distribution and behavior, and minimal 

impacts to recruitment or survival 

anticipated. While there is a lack of 

specific scientific information to allow 

an assessment of the duration, intensity, 

or distribution of effects to prey in 

specific locations at specific times and 

in response to specific surveys, NMFS’ 

review of the available information does 

not indicate that such effects could be 

significant enough to impact marine 

mammal prey to the extent that marine 

mammal fitness would be affected. We 

agree that seismic surveys could affect 

certain marine mammal prey species, 

and addressed these potential effects, as 

well as the potential for those effects to 

impact marine mammal populations, in 

our notice of proposed IHA (85 FR 

19580; April 7, 2020). As stated in the 

notice of proposed IHA, our review of 

the available information and the 

specific nature of the activities 

considered herein suggest that L–DEO’s 

proposed survey activities are not likely 

to have more than short-term adverse 

effects on any prey habitat or 

populations of prey species. Further, 

any impacts to prey species are not 

expected to result in significant or longterm consequences for individual 

marine mammals, or to contribute to 

adverse impacts on their populations. 

For additional information on the 

effects of L–DEO’s proposed survey on 

salmon species present in the survey 

area, we refer the reader to the 

Biological Opinion issued by the NMFS 

Office of Protected Resources, 

Interagency Cooperation Division 

(available at https://www.fisheries.

noaa.gov/national/marine-mammalprotection/incidental-takeauthorizations-research-and-otheractivities). In summary, fish react to 

sounds which are especially strong and/ 

or intermittent low-frequency sounds, 

and behavioral responses such as flight 

or avoidance are the most likely effects. 

However, the reaction of fish to airguns 

depends on the physiological state of 

the fish, past exposures, motivation 

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

other environmental factors. While we 

agree that some studies have 

demonstrated that airgun sounds might 

affect the distribution and behavior of 

some fishes, potentially impacting 

foraging opportunities or increasing 

energetic costs (e.g., Fewtrell and 

McCauley, 2012; Pearson et al., 1992; 

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

Paxton et al., 2017), our review shows 

that the weight of evidence indicates 

either no or only a slight reaction to 

noise (e.g., Miller and Cripps, 2013; 

Dalen and Knutsen, 1987; Pena et al., 

2013; Chapman and Hawkins, 1969; 

Wardle et al., 2001; Sara et al., 2007; 

Jorgenson and Gyselman, 2009; Blaxter 

et al., 1981; Cott et al., 2012; Boeger et 

al., 2006), and that, most commonly, 

while there may be impacts to fish as a 

result of noise from nearby airguns, any 

effects will be temporary. For example, 

investigators reported significant, shortterm declines in commercial fishing 

catch rate of gadid fishes during and for 

up to five days after seismic survey 

operations, but the catch rate 

subsequently returned to normal (Engas 

29094 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

et al., 1996; Engas and Lokkeborg, 

2002). Other studies have reported 

similar findings (e.g., Hassel et al., 

2004). Skalski et al. (1992) also found a 

reduction in catch rates—for rockfish 

(Sebastes spp.) in response to controlled 

airgun exposure—but suggested that the 

mechanism underlying the decline was 

not dispersal but rather decreased 

responsiveness to baited hooks 

associated with an alarm behavioral 

response. A companion study showed 

that alarm and startle responses were 

not sustained following the removal of 

the sound source (Pearson et al., 1992). 

Therefore, Skalski et al. (1992) 

suggested that the effects on fish 

abundance may be transitory, primarily 

occurring during the sound exposure 

itself. In some cases, effects on catch 

rates are variable within a study, which 

may be more broadly representative of 

temporary displacement of fish in 

response to airgun noise (i.e., catch rates 

may increase in some locations and 

decrease in others) than any long-term 

damage to the fish themselves (Streever 

et al., 2016). 

Sound pressure levels (SPLs) of 

sufficient strength have been known to 

cause injury to fish and fish mortality 

and, in some studies, fish auditory 

systems have been damaged by airgun 

noise (McCauley et al., 2003; Popper et 

al., 2005; Song et al., 2008). However, in 

most fish species, hair cells in the ear 

continuously regenerate and loss of 

auditory function likely is restored 

when damaged cells are replaced with 

new cells. Halvorsen et al. (2012) 

showed that a temporary threshold shift 

(TTS) of 4–6 decibel (dB) was 

recoverable within 24 hours for one 

species. Impacts would be most severe 

when the individual fish is close to the 

source and when the duration of 

exposure is long—both of which are 

conditions unlikely to occur for surveys 

that are necessarily transient in any 

given location and likely result in brief, 

infrequent noise exposure to prey 

species in any given area. For these 

surveys, the sound source is constantly 

moving, and most fish would likely 

avoid the sound source prior to 

receiving sound of sufficient intensity to 

cause physiological or anatomical 

damage. In addition, ramp-up may 

allow certain fish species the 

opportunity to move further away from 

the sound source. 

NMFS considered the research 

referenced by the ENGOs and disagrees 

with the assertion that ‘‘[NMFS] 

irrationally discounts those impacts,’’ as 

well as with the commenters’ 

interpretation of the literature. A recent 

comprehensive review (Carroll et al., 

2017) found that results are mixed as to 

the effects of airgun noise on the prey 

of marine mammals. While some studies 

suggest a change in prey distribution 

and/or a reduction in prey abundance 

following the use of seismic airguns, 

others suggest no effects or even 

positive effects in prey abundance. 

Regarding Paxton et al. (2017), which 

describes findings related to the effects 

of a 2014 seismic survey on a reef off of 

North Carolina, while the study did 

show a 78 percent decrease in observed 

nighttime abundance for certain species, 

it is important to note that the evening 

hours during which the decline in fish 

habitat use was recorded (via video 

recording) occurred on the same day 

that the seismic survey passed, and no 

subsequent data is presented to support 

an inference that the response was longlasting. Additionally, given that the 

finding is based on video images, the 

lack of recorded fish presence does not 

support a conclusion that the fish 

actually moved away from the site or 

suffered any serious impairment 

because fish may remain present yet not 

be recorded on video. In summary, this 

particular study corroborates prior 

studies demonstrating a startle response 

or short-term displacement. 

The Carroll et al. (2017) review article 

concluded that, while laboratory results 

provide scientific evidence for highintensity and low-frequency soundinduced physical trauma and other 

negative effects on some fish and 

invertebrates, the sound exposure 

scenarios in some cases are not realistic 

to those encountered by marine 

organisms during routine seismic 

operations. The review finds that there 

has been no evidence of reduced catch 

or abundance following seismic 

activities for invertebrates, and that 

there is conflicting evidence for fish 

with catch observed to increase, 

decrease, or remain the same. Further, 

where there is evidence for decreased 

catch rates in response to airgun noise, 

these findings provide no information 

about the underlying biological cause of 

catch rate reduction (Carroll et al., 

2017). 

In summary, the scientific literature 

demonstrates that impacts of seismic 

surveys on marine mammal prey species 

will likely be limited to behavioral 

responses, the majority of prey species 

will be capable of moving out of the area 

during surveys, a rapid return to normal 

recruitment, distribution, and behavior 

for prey species is anticipated, and, 

overall, impacts to prey species, if any, 

will be minor and temporary. Prey 

species exposed to sound might move 

away from the sound source, experience 

TTS, experience masking of biologically 

relevant sounds, or show no obvious 

direct effects. Mortality from 

decompression injuries is possible in 

close proximity to a sound, but only 

limited data on mortality in response to 

airgun noise exposure are available 

(Hawkins et al., 2014). The most likely 

impacts for most prey species in a given 

survey area would be temporary 

avoidance of the area. Surveys using 

towed airgun arrays move through an 

area relatively quickly, limiting 

exposure to multiple impulsive sounds. 

In all cases, sound levels would return 

to ambient once a survey moves out of 

the area or ends and the noise source is 

shut down and, when exposure to 

sound ends, behavioral and/or 

physiological responses are expected to 

end relatively quickly (McCauley et al., 

2000b). The duration of fish avoidance 

of a given area after survey effort stops 

is unknown, but a rapid return to 

normal recruitment, distribution, and 

behavior is anticipated. While the 

potential for disruption of spawning 

aggregations or schools of important 

prey species can be meaningful on a 

local scale, the mobile and temporary 

nature of most surveys and the 

likelihood of temporary avoidance 

behavior suggest that impacts would be 

minor. 

NMFS believes that no evidence is 

presented to contradict our conclusions 

regarding likely impacts to marine 

mammals due to effects on prey species, 

i.e., that impacts of the specified activity 

are not likely to have more than shortterm adverse effects on any prey habitat 

or populations of prey species, and that 

any effects that do occur are not 

expected to result in significant or longterm consequences for individual 

marine mammals, or to contribute to 

adverse impacts on their populations. 

Finally, we note that the National 

Science Foundation (NSF) is funding a 

study run by Oregon State University to 

assess the effects of L–DEO’s survey 

activities on rockfish, Dungeness crab, 

and longnose skate. While the species 

chosen for this study do not represent 

important prey species for Southern 

Resident killer whales, which were the 

primary concern of the ENGOs, the 

study will provide important 

information on the effects of seismic 

surveys on nearshore species. 

Comment 4: The ENGOs commented 

that in making the negligible impact 

determination, NMFS underestimated 

the potential harm to the relevant stocks 

and distinct population segments (DPSs) 

of humpback whales, adding that the 

stock definitions for humpback whales 

are outdated and should match the DPSs 

as defined under the Endangered 

Species Act. The ENGOs assert that the 

takes proposed by NMFS are more than 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29095 

negligible for the California/Oregon/ 

Washington stock because the annual 

rate of serious injury and mortality (40.2 

humpback whales per year) exceeds the 

potential biological removal (PBR; 33.4 

humpbacks per year). Additionally, for 

both humpback and blue whales, the 

ENGOs assert that take by Level A 

harassment in the form of permanent 

hearing impairment amounts to serious 

injury, therefore the negligible impact 

determination overly relies on the 

assumption that there will be no serious 

injury or mortality from the seismic 

survey. 

Response: First, NMFS agrees that the 

alignment of MMPA stocks and 

Endangered Species Act (ESA) DPSs of 

humpback whales is important, and is 

actively working on rectifying the 

differences between stocks and DPSs. 

However, this issue is outside the scope 

of the action considered here. NMFS 

disagrees with the ENGOs’ assertion that 

the authorized take of humpback or blue 

whales (or any species of marine 

mammal) by Level A harassment 

constitutes serious injury or has any 

relation to the PBR of the stock. PBR is 

defined in the MMPA (16 U.S.C. 

1362(20)) 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’’ and is 

a measure to be considered when 

evaluating the effects of mortality or 

serious injury on a marine mammal 

species or stock. There is no evidence 

that permanent threshold shift (PTS) 

can lead to mortality such that it should 

be considered ‘‘serious injury’’ or 

‘‘removing’’ an individual from a stock. 

Therefore, it is not appropriate to use 

the PBR metric to directly evaluate the 

effects of Level A harassment (e.g., PTS) 

on a stock in the manner suggested by 

the ENGOs. Given the short duration of 

exposure, only low levels of hearing 

impairment are likely to occur, and 

would not affect the fitness of 

individual marine mammals or 

populations. 

As noted above, the PBR metric 

concerns levels of allowable removals 

from a population. Therefore, the PBR 

metric is not directly related to an 

assessment of negligible impact for this 

specified activity, which does not 

involve any expected potential for 

serious injury or mortality. PBR is not 

an appropriate metric with which to 

evaluate Level B harassment. However, 

we appropriately do consider levels of 

ongoing anthropogenic mortality from 

other sources, such as vessel strike, in 

relation to calculated PBR values as an 

important contextual factor in our 

negligible impact analysis, but a direct 

comparison of takes by harassment to 

the PBR value is not germane. While it 

is conceptually possible to link 

disturbance to potential fitness impacts 

to individuals over time (e.g., 

population consequences of 

disturbance), we have no evidence that 

is the case here and the take authorized 

here is not expected to affect the 

reproduction or survivorship of any 

individual marine mammals. 

Comment 5: The ENGOs assert that 

the negligible impact determination also 

relies on an expectation that marine 

mammals would be likely to move away 

from the sound source, which 

contradicts other statements from the 

notice of proposed IHA that avoidance 

is not assumed to occur because ‘‘the 

extent to which marine mammals would 

move away from the sound source is 

difficult to quantify and is therefore not 

accounted for in the take estimates.’’ 

The commenters go on to state that 

animals avoiding the sound source still 

provokes an adverse behavioral reaction 

which displaces the animal from 

preferred habitat and potentially toward 

predators or shore with a risk of 

stranding. 

Response: NMFS does not rely on 

avoidance behaviors to make its 

negligible impact determination. NMFS 

agrees that avoidance of preferred 

habitat may temporarily limit optimal 

feeding or other biologically important 

behaviors. NMFS does not adjust take 

estimates based on the assumption that 

marine mammals would avoid the area, 

as the avoidance itself may constitute 

behavioral harassment. However, 

avoiding the sound source prevents the 

animal from exposure to the highest 

source levels, reducing the likelihood of 

temporary (Level B harassment) or 

permanent hearing impairment (Level A 

harassment), and reducing the intensity 

and/or duration of the harassment 

event. The avoidance is expected to be 

temporary, and animals are likely to 

return to the area after the survey vessel 

has passed through. In consideration of 

the likelihood of animals to 

independently avoid the sound source, 

and the mitigation requirements to shut 

down the airgun array if animals do 

approach within a certain distance, 

NMFS finds that the level of take 

expected to result from the survey is 

unlikely to have any impact on fitness 

or reproduction of individual animals, 

let alone populations. 

Comment 6: Citing studies suggesting 

that blue whales are especially sensitive 

to high intensity anthropogenic noise, 

such as mid-frequency sonar (e.g., 

Goldbogen et al., 2013), the ENGOs 

suggest that NMFS’ consideration of the 

impact of the proposed activities on 

blue whales may underestimate the 

adverse impacts on the stock. 

Response: As discussed in the notice 

of proposed IHA, Goldbogen et al. 

(2013) found blue whales feeding on 

highly concentrated prey in shallow 

depths were less likely to respond and 

cease foraging than whales feeding on 

deep, dispersed prey when exposed to 

simulated sonar sources, suggesting that 

the benefits of feeding for blue whales 

foraging on high-density prey may 

outweigh perceived harm from the 

acoustic stimulus, such as the seismic 

survey. Southall et al. (2019b) observed 

that after exposure to simulated and 

operational mid-frequency active sonar, 

more than 50 percent of blue whales in 

deep-diving states responded to the 

sonar, while no behavioral response was 

observed in shallow-feeding blue 

whales. Southall et al. (2019b) noted 

that the behavioral responses they 

observed were generally brief, of low to 

moderate severity, and highly 

dependent on exposure context 

(behavioral state, source-to-whale 

horizontal range, and prey availability). 

The proposed survey area does not 

represent a major feeding area for blue 

whales and any disruption of feeding is 

likely to be short-term and of low to 

sometimes moderate severity, with no 

anticipated effect on reproduction or 

survival for individual whales or the 

population as a whole. 

Comment 7: Deep Green Wilderness 

and the ENGOs noted that North Pacific 

right whales have been documented 

within the survey area, and 

recommended NMFS consider the 

potential effects of the survey on the 

species. Deep Green Wilderness referred 

to sightings of a North Pacific right 

whale at Swiftsure Bank in 2013, and 

the ENGOs noted an account of a 

sighting of a North Pacific right whale 

off northern Vancouver Island in May 

2020. 

Response: We thank the organizations 

for providing information on recent 

observations of North Pacific right 

whales in the survey area. NMFS shares 

the commenters’ concern regarding the 

status of this endangered species. 

Although sightings have been reported 

in the survey area, the rate of sightings 

is less than one per year and NMFS has 

determined the likelihood of the 

proposed 37-day survey encountering a 

North Pacific right whale is 

discountable. However, in the very 

unlikely event a North Pacific right 

whale is detected during the survey, at 

any distance, L–DEO must immediately 

shut down the airgun array to prevent 

exposure to potentially injurious sound 

levels and to minimize the intensity and 

29096 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

duration of any sound exposure, and 

must immediately report the 

observation to NMFS and Canada’s DFO 

to further inform research on the 

distribution of the species. 

Comment 8: The ENGOs challenge 

NMFS’ preliminary finding that the 

proposed take numbers are of no more 

than small numbers of marine 

mammals. The ENGOs reference a court 

decision that they assert supports a 

lower ‘‘small numbers’’ threshold, and 

highlight certain species for which the 

commenters deem the take to be too 

high. 

Response: The reference to a 

supposed take limit of 12 percent for 

small numbers comes from a 2003 

district court opinion (Natural 

Resources Defense Council v. Evans, 

279 F. Supp. 2d 1129 (N.D. Cal. 2003)). 

However, given the particular 

administrative record and 

circumstances in that case, including 

the fact that our small numbers finding 

for the challenged incidental take rule 

was based on an invalid regulatory 

definition of small numbers, we view 

the district court’s opinion regarding 12 

percent as dicta. Moreover, since that 

time the Ninth Circuit Court of Appeals 

has upheld a small numbers finding that 

was not based on a quantitative 

calculation. Center for Biological 

Diversity v. Salazar, 695 F.3d 893 (9th 

Cir. 2012). To maintain an interpretation 

of small numbers as a proportion of a 

species or stock that does not conflate 

with negligible impact, we use the 

following framework. A plain reading of 

‘‘small’’ implies as corollary that there 

also could be ‘‘medium’’ or ‘‘large’’ 

numbers of animals from the species or 

stock taken. We therefore use a simple 

approach that establishes equal bins 

corresponding to small, medium, and 

large proportions of the population 

abundance. 

NMFS’s practice for making small 

numbers determinations is to compare 

the number of individuals estimated 

and authorized to be taken (often using 

estimates of total instances of take, 

without regard to whether individuals 

are exposed more than once) against the 

best available abundance estimate for 

that species or stock. We note, however, 

that although NMFS’s implementing 

regulations require applications for 

incidental take to include an estimate of 

the marine mammals to be taken, there 

is nothing in paragraphs (A) or (D) of 

section 101(a)(5) that requires NMFS to 

quantify or estimate numbers of marine 

mammals to be taken for purposes of 

evaluating whether the number is small. 

(See CBD v. Salazar.) While it can be 

challenging to predict the numbers of 

individual marine mammals that will be 

taken by an activity (again, many 

models calculate instances of take and 

are unable to account for repeated 

exposures of individuals), in some cases 

we are able to generate a reasonable 

estimate utilizing a combination of 

quantitative tools and qualitative 

information. When it is possible to 

predict with relative confidence the 

number of individual marine mammals 

of each species or stock that are likely 

to be taken, the small numbers 

determination should be based directly 

upon whether or not these estimates 

exceed one third of the stock 

abundance. In other words, consistent 

with past practice, when the estimated 

number of individual animals taken 

(which may or may not be assumed as 

equal to the total number of takes, 

depending on the available information) 

is up to, but not greater than, one third 

of the species or stock abundance, 

NMFS will determine that the numbers 

of marine mammals taken of a species 

or stock are small. 

Finally, regarding the species 

highlighted by the ENGOs with 

proposed take above 20 percent of the 

stock (Pacific white-sided dolphin, 

Risso’s dolphin, pygmy and dwarf 

sperm whale, Dall’s porpoise, harbor 

porpoise, northern fur seal and harbor 

seal), the revised take estimates for all 

of the aforementioned stocks aside from 

the California/Oregon/Washington stock 

of Dall’s porpoise and Northern Oregon/ 

Washington Coast stock of harbor 

porpoise represent under one-third of 

the stock. The analysis of these two 

stocks is discussed further in the Small 

Numbers section of this notice. 

Comment 9: The ENGOs further object 

to NMFS’ small numbers determination 

for the Southern Resident killer whale, 

for which NMFS proposed to authorize 

take of more than 57 percent of the 

stock. Regarding the Southern Resident 

killer whale take estimate, the ENGOs 

disagree with NMFS’ assumption that 

the number of individual Southern 

Resident killer whales taken by Level B 

harassment will be fewer than the total 

estimated instances of take due to the 

historical pattern of Southern Resident 

killer whales occupying the inland 

waters of the Salish Sea during the 

summer months. Additionally, because 

they travel in pods, the commenters 

assert that there is risk of exposure of an 

entire pod to airgun blasting, and state 

that they are unclear whether such 

aggregation has been considered. 

Response: The ENGO’s objection to 

NMFS’ small numbers threshold was 

addressed in the previous response, but 

we also note here that using the revised 

survey tracklines, the authorized take of 

Southern Resident killer whales 

represents only 13.7 percent of the 

stock, which falls under NMFS’ 

threshold for small numbers, even if all 

takes represent different individuals 

taken by Level B harassment. The 

authorized take is less than the size of 

any pod of Southern Residents (J, K, or 

L pods), and is more likely to represent 

a single matriline (typically two to nine 

killer whales; Weiss et al., 2020) 

exposed to the survey on one or two 

days of the survey. NMFS agrees that 

the seasonal distribution of Southern 

Resident killer whales in recent years 

has deviated from the historical pattern 

of residency within the Salish Sea (e.g., 

Shields et al., 2018), but note that our 

discussion of the distribution of 

Southern Resident killer whales was in 

the context of the U.S. Navy density 

models used to estimate take, which 

were created with the assumption that 

the entire population was either within 

the Salish Sea or outside the Salish Sea 

on the outer coast at any given time 

(U.S. Navy 2019). Southern Resident 

killer whales may be encountered 

during the survey along the coast, but 

the revised tracklines are expected to 

reduce the likelihood of whole pods 

being exposed to sound from the 

seismic survey by avoiding surveying in 

areas of expected high Southern 

Resident killer whale occurrence. 

Additionally, L–DEO is required to shut 

down the airgun array if killer whales 

(of any ecotype) are observed at any 

distance. Killer whales are highly 

visible animals, especially when 

traveling as large pods as the ENGOs 

suggest, and we expect PSOs will be 

able to detect killer whales at sufficient 

distances to implement shutdown 

procedures to avoid exposing large pods 

of killer whales to sounds from the 

survey. 

Comment 10: The ENGOs commented 

that NMFS must include estimated takes 

off Canada in making the small numbers 

determination, adding that since the 

take prohibition applies outside U.S. 

waters, the Service must make a small 

numbers determination that analyzes all 

of the estimated take. The commenters 

state that, accordingly, NMFS must 

demonstrate compliance with these 

standards and may not issue the 

authorization without fully analyzing 

and authorizing all take contemplated 

under this action. The commenters also 

state that it is unclear in the small 

numbers determination whether the 

takes in Canadian waters have been 

taken into consideration. The ENGOs 

also expressed concern that the small 

numbers determination was based on 1 

year of activities and did not consider 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29097 

the potential renewal of the 

authorization. 

Response: NMFS has not authorized 

any take of marine mammals within the 

territorial waters of Canada. An estimate 

of take that may occur within Canadian 

territorial waters is presented in Table 

11, and the take has been considered in 

our negligible impact determination as 

part of the larger implications of the 

survey on the marine mammal 

populations and habitat in the survey 

area. However, our small numbers 

analysis applies only to the take we 

have authorized. NMFS has made the 

necessary small numbers and negligible 

impact determinations for this 

authorization. 

The ENGOs appear to misunderstand 

the context in which a potential renewal 

IHA could be issued for this activity, as 

well as the requirements for issuing a 

renewal IHA. Although renewal IHAs in 

general may be issued in appropriate 

circumstances for up to another year of 

identical or nearly identical activities as 

were covered by the initial IHA, this 

context is not relevant to the proposed 

seismic survey. L–DEO would not 

conduct the survey as planned and then 

duplicate the survey activities in a 

subsequent year. Regardless, NMFS 

would not grant a renewal IHA in those 

circumstances. However, if the planned 

survey were unexpectedly delayed for 

another year, NMFS could consider a 

request for issuance of a renewal IHA. 

In order to do so, NMFS would need to 

review all relevant information, 

including the status of the affected 

species or stocks and any other 

pertinent information, such as 

information relevant to the small 

numbers determination. In short, 

potential consideration of a renewal in 

this context would necessarily be 

associated with the same activity 

associated with this IHA, in the event 

that it is not conducted during the 

period of effectiveness for this IHA, and 

would entail a review of all relevant 

information to ensure that the findings 

NMFS has made in support of issuance 

of this initial IHA remain valid. 

Comment 11: The ENGOs 

recommended NMFS analyze the effects 

of L–DEO’s use of a multi-beam 

echosounder (MBES) associated with 

the survey, noting that the proposed 

equipment (the Kongsberg Simrad E122) 

is similar to another Kongsberg system 

that was closely associated with a 2008 

mass stranding of melon-headed whales 

in Madagascar. The ENGOs 

recommended NMFS apply its take 

threshold for continuous noise sources 

(120 dB) rather than its threshold for 

intermittent sources (160 dB) to the 

proposed system and revise its take 

estimates accordingly. Further, NMFS 

should not assume, for purposes of 

making its negligible impact 

determinations, that the severity of 

impacts from an airgun array operating 

concurrently with such an echosounder 

system would be equivalent to that of an 

airgun array operating alone. 

Response: Although it is correct that 

an investigation of the stranding event 

referenced by the ENGOs indicated that 

use of a high-frequency mapping system 

(12-kilohertz (kHz) MBES) was the most 

plausible and likely initial behavioral 

trigger of the event (with the caveat that 

there was no unequivocal and easily 

identifiable single cause), the panel also 

noted several site- and situation-specific 

secondary factors that may have 

contributed to the avoidance responses 

that led to the eventual entrapment and 

mortality of the whales (Southall et al., 

2013). Specifically, regarding survey 

patterns prior to the event and in 

relation to bathymetry, the vessel 

transited in a north-south direction on 

the shelf break parallel to the shore, 

ensonifying deep-water habitat prior to 

operating intermittently in a 

concentrated area offshore from the 

stranding site. This may have trapped 

the animals between the sound source 

and the shore, thus driving them 

towards the lagoon system. Shorewarddirected surface currents and elevated 

chlorophyll levels in the area preceding 

the event may also have played a role. 

The risk of similar events recurring is 

expected to be very low, given the 

extensive use of active acoustic systems 

used for scientific and navigational 

purposes worldwide on a daily basis 

and the lack of direct evidence of such 

responses previously reported. The only 

report of a stranding that may be 

associated with this type of sound 

source is the one reported in 

Madagascar. 

NMFS disagrees with the 

recommendation that the 120 dB 

threshold should be applied to estimate 

takes incidental to use of the MBES. 

Sound sources can be divided into 

broad categories based on various 

criteria or for various purposes. As 

discussed by Richardson et al. (1995), 

source characteristics include strength 

of signal amplitude, distribution of 

sound frequency and, importantly in 

context of these thresholds, variability 

over time. With regard to temporal 

properties, sounds are generally 

considered to be either continuous or 

transient (i.e., intermittent). Continuous 

sounds, which are produced by the 

industrial noise sources for which the 

120-dB behavioral harassment threshold 

was selected, are simply those whose 

sound pressure level remains above 

ambient sound during the observation 

period (ANSI, 2005). Intermittent 

sounds are defined as sounds with 

interrupted levels of low or no sound 

(NIOSH, 1998). Simply put, a 

continuous noise source produces a 

signal that continues over time, while 

an intermittent source produces signals 

of relatively short duration having an 

obvious start and end with predictable 

patterns of bursts of sound and silent 

periods (i.e., duty cycle) (Richardson 

and Malme, 1993). It is this fundamental 

temporal distinction that is most 

important for categorizing sound types 

in terms of their potential to cause a 

behavioral response. For example, 

Gomez et al. (2016) found a significant 

relationship between source type and 

marine mammal behavioral response 

when sources were split into continuous 

(e.g., shipping, icebreaking, drilling) 

versus intermittent (e.g., sonar, seismic, 

explosives) types. In addition, there 

have been various studies noting 

differences in responses to intermittent 

and continuous sound sources for other 

species (e.g., Neo et al., 2014; Radford 

et al., 2016; Nichols et al., 2015). 

Sound sources may also be 

categorized based on their potential to 

cause physical damage to auditory 

structures and/or result in threshold 

shifts. In contrast to the temporal 

distinction discussed above, the most 

important factor for understanding the 

differing potential for these outcomes 

across source types is simply whether 

the sound is impulsive or not. Impulsive 

sounds, such as those produced by 

airguns, are defined as sounds which 

are typically transient, brief (<1 second 

(sec)), broadband, and consist of a high 

peak pressure with rapid rise time and 

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

These sounds are generally considered 

to have greater potential to cause 

auditory injury and/or result in 

threshold shifts. Non-impulsive sounds 

can be broadband, narrowband or tonal, 

brief or prolonged, continuous or 

intermittent, and typically do not have 

the high peak pressure with rapid rise/ 

decay time that impulsive sounds do 

(ANSI, 1995; NIOSH, 1998). Because the 

selection of the 160-dB behavioral 

threshold was focused largely on airgun 

signals, it has historically been 

commonly referred to as the ‘‘impulse 

noise’’ threshold (including by NMFS). 

However, this longstanding confusion in 

terminology—i.e., the erroneous 

impulsive/continuous dichotomy— 

presents a narrow view of the sound 

sources to which the thresholds apply, 

and inappropriately implies a limitation 

in scope of applicability for the 160-dB 

behavioral threshold in particular. 

29098 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

An impulsive sound is by definition 

intermittent; however, not all 

intermittent sounds are impulsive. 

Many sound sources for which it is 

generally appropriate to consider the 

authorization of incidental take are in 

fact either impulsive (and intermittent) 

(e.g., impact pile driving) or continuous 

(and non-impulsive) (e.g., vibratory pile 

driving). However, scientific sonars 

(such as MBESs) present a less common 

case where the sound produced is 

considered intermittent but nonimpulsive. We note also the 

commenters’ assertion that the system 

produces ‘‘virtually continuous noise 

output’’ in support of their 

recommendation to apply the 

continuous noise threshold to 

evaluation of this source. In context of 

marine mammal hearing, this would 

mean that the interval between signals 

would not be discernible to the animal, 

rendering them effectively continuous. 

However, echosounder signals are 

emitted in a similar fashion as 

odontocete echolocation click trains. 

Research indicates that marine 

mammals, in general, have extremely 

fine auditory temporal resolution and 

can detect each signal separately (e.g., 

Au et al., 1988; Dolphin et al., 1995; 

Supin and Popov, 1995; Mooney et al., 

2009), especially for species with 

echolocation capabilities. Therefore, it 

is highly unlikely that marine mammals 

would perceive echosounder signals as 

being continuous. 

Given the existing paradigm— 

dichotomous thresholds appropriate for 

generic use in evaluating the potential 

for behavioral harassment resulting from 

exposure to continuous or intermittent 

sound sources—the ENGOs do not 

adequately explain why potential 

harassment from an intermittent sound 

source should be evaluated using a 

threshold developed for use with 

continuous sound sources. Therefore, 

we have not reevaluated L–DEO’s use of 

the MBES using the 120 dB continuous 

noise threshold. 

As discussed in the notice of 

proposed IHA, due to the lower source 

level of the MBES relative to the R/V 

Langseth’s airgun array, sounds from the 

MBES are expected to be effectively 

subsumed by the sounds from the 

airgun array when both sources are 

operational. Thus, NMFS has 

determined that any marine mammal 

potentially exposed to sounds from the 

MBES would already have been exposed 

to sounds from the airgun array, which 

are expected to propagate further in the 

water, when both sources are 

operational. NMFS has determined that, 

given the movement and speed of the 

vessel and the intermittent and narrow 

downward-directed nature of the 

sounds emitted by the MBES (each ping 

emitted by the MBES consists of eight 

(in water >1,000 m deep) or four (<1,000 

m) successive fan-shaped transmissions, 

each ensonifying a sector that extends 1° 

fore-aft), the MBES would result in no 

more than one or two brief ping 

exposures to any individual marine 

mammal, if any exposure were to occur. 

The ENGOs do not offer any evidence in 

support of their contention that 

potentially greater impacts than we have 

considered should be assumed likely in 

relation to use of this source. 

Comment 12: The ENGOs comment 

that NMFS has failed to implement 

‘‘means of effecting the least practicable 

impact’’ on marine mammals and assert 

that NMFS relies on mitigation 

measures that are known to be 

ineffective (e.g., real-time detectionbased measures). 

Response: Under section 101(a)(5)(D) 

of the MMPA, NMFS must set forth the 

permissible methods of taking by 

harassment pursuant to such activity, 

and other means of effecting the least 

practicable impact on such species or 

stock and its habitat, paying particular 

attention to rookeries, mating grounds, 

and areas of similar significance, and on 

the availability of such species or stock 

for taking for subsistence uses 

(hereinafter referred to as least 

practicable adverse impact). NMFS does 

not have a regulatory definition for least 

practicable adverse impact. 

NMFS disagrees with the assertion 

that we have failed to meet the least 

practicable adverse impact standard in 

this case. NMFS considered all 

recommended mitigation in the context 

of both the reduction of impacts on 

marine mammal species and stocks and 

their habitat and the practicability of 

such mitigation in reaching the required 

set of measures that we believe satisfy 

the least practicable adverse impact 

standard. 

NMFS’ evaluation of potential 

mitigation measures includes 

consideration of two primary factors: 

(1) The manner in which, and the 

degree to which, implementation of the 

potential measure(s) is expected to 

reduce adverse impacts to marine 

mammal species or stocks, their habitat, 

and their availability for subsistence 

uses (where relevant). This analysis 

considers such things as the nature of 

the potential adverse impact (such as 

likelihood, scope, and range), the 

likelihood that the measure will be 

effective if implemented, and the 

likelihood of successful 

implementation. 

(2) The practicability of the measures 

for applicant implementation. 

Practicability of implementation may 

consider such things as cost, impact on 

activities, personnel safety, and 

practicality of implementation. 

While the language of the least 

practicable adverse impact standard 

calls for minimizing impacts to affected 

species or stocks and their habitat, 

NMFS recognizes that the reduction of 

impacts to those species or stocks 

accrues through the application of 

mitigation measures that limit impacts 

to individual animals. Accordingly, 

NMFS’ analysis focuses on measures 

that are designed to avoid or minimize 

impacts on individual marine mammals 

that are likely to increase the probability 

or severity of population-level effects. 

While direct evidence of impacts to 

species or stocks from a specified 

activity is rarely available, and 

additional study is still needed to 

understand how specific disturbance 

events affect the fitness of individuals of 

certain species, there have been 

improvements in understanding the 

process by which disturbance effects are 

translated to the population. With 

recent scientific advancements (both 

marine mammal energetic research and 

the development of energetic 

frameworks), the relative likelihood or 

degree of impacts on species or stocks 

may often be inferred given a detailed 

understanding of the activity, the 

environment, and the affected species or 

stocks. This same information is used in 

the development of mitigation measures 

and helps us understand how mitigation 

measures contribute to lessening effects 

(or the risk thereof) to species or stocks. 

NMFS also acknowledges that there is 

always the potential that new 

information, or a new recommendation 

that had not previously been 

considered, becomes available and 

necessitates re-evaluation of mitigation 

measures to see if further reductions of 

population impacts are possible and 

practicable. 

In the evaluation of specific measures, 

the details of the specified activity will 

necessarily inform each of the two 

primary factors discussed above 

(expected reduction of impacts and 

practicability) and are carefully 

considered to determine the types of 

mitigation that are appropriate under 

the least practicable adverse impact 

standard. Analysis of how a potential 

mitigation measure may reduce adverse 

impacts on a marine mammal stock or 

species and practicability of 

implementation are not issues that can 

be meaningfully evaluated through a 

yes/no lens. The manner in which, and 

the degree to which, implementation of 

a measure is expected to reduce 

impacts, as well as its practicability, can 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29099 

vary widely. For example, a time-area 

restriction could be of very high value 

for reducing the potential for, or severity 

of, population-level impacts (e.g., 

avoiding disturbance of feeding females 

in an area of established biological 

importance) or it could be of lower 

value (e.g., decreased disturbance in an 

area of high productivity but of less 

firmly established biological 

importance). Regarding practicability, a 

measure might involve restrictions in an 

area or time that impede the operator’s 

ability to acquire necessary data (higher 

impact), or it could mean incremental 

delays that increase operational costs 

but still allow the activity to be 

conducted (lower impact). A 

responsible evaluation of ‘‘least 

practicable adverse impact’’ will 

consider the factors along these realistic 

scales. Expected effects of the activity 

and of the mitigation as well as status 

of the stock all weigh into these 

considerations. Accordingly, the greater 

the likelihood that a measure will 

contribute to reducing the probability or 

severity of adverse impacts to the 

species or stock or their habitat, the 

greater the weight that measure is given 

when considered in combination with 

practicability to determine the 

appropriateness of the mitigation 

measure, and vice versa. Consideration 

of these factors is discussed in greater 

detail below. 

1. Reduction of Adverse Impacts to 

Marine Mammal Species or Stocks and 

Their Habitat 

The emphasis given to a measure’s 

ability to reduce the impacts on a 

species or stock considers the degree, 

likelihood, and context of the 

anticipated reduction of impacts to 

individuals (and how many individuals) 

as well as the status of the species or 

stock. 

The ultimate impact on any 

individual from a disturbance event 

(which informs the likelihood of 

adverse species- or stock-level effects) is 

dependent on the circumstances and 

associated contextual factors, such as 

duration of exposure to stressors. 

Though any proposed mitigation needs 

to be evaluated in the context of the 

specific activity and the species or 

stocks affected, measures with the 

following types of effects have greater 

value in reducing the likelihood or 

severity of adverse species- or stocklevel impacts: Avoiding or minimizing 

injury or mortality; limiting interruption 

of known feeding, breeding, mother/ 

young, or resting behaviors; minimizing 

the abandonment of important habitat 

(temporally and spatially); minimizing 

the number of individuals subjected to 

these types of disruptions; and limiting 

degradation of habitat. Mitigating these 

types of effects is intended to reduce the 

likelihood that the activity will result in 

energetic or other types of impacts that 

are more likely to result in reduced 

reproductive success or survivorship. It 

is also important to consider the degree 

of impacts that are expected in the 

absence of mitigation in order to assess 

the added value of any potential 

measures. Finally, because the least 

practicable adverse impact standard 

gives NMFS discretion to weigh a 

variety of factors when determining 

appropriate mitigation measures and 

because the focus of the standard is on 

reducing impacts at the species or stock 

level, the least practicable adverse 

impact standard does not compel 

mitigation for every kind of take, or 

every individual taken, if that mitigation 

is unlikely to meaningfully contribute to 

the reduction of adverse impacts on the 

species or stock and its habitat, even 

when practicable for implementation by 

the applicant. 

The status of the species or stock is 

also relevant in evaluating the 

appropriateness of potential mitigation 

measures in the context of least 

practicable adverse impact. The 

following are examples of factors that 

may (either alone, or in combination) 

result in greater emphasis on the 

importance of a mitigation measure in 

reducing impacts on a species or stock: 

The stock is known to be decreasing or 

status is unknown, but believed to be 

declining; the known annual mortality 

(from any source) is approaching or 

exceeding the PBR level; the affected 

species or stock is a small, resident 

population; or the stock is involved in 

a UME or has other known 

vulnerabilities, such as recovering from 

an oil spill. 

Habitat mitigation, particularly as it 

relates to rookeries, mating grounds, and 

areas of similar significance, is also 

relevant to achieving the standard and 

can include measures such as reducing 

impacts of the activity on known prey 

utilized in the activity area or reducing 

impacts on physical habitat. As with 

species- or stock-related mitigation, the 

emphasis given to a measure’s ability to 

reduce impacts on a species or stock’s 

habitat considers the degree, likelihood, 

and context of the anticipated reduction 

of impacts to habitat. Because habitat 

value is informed by marine mammal 

presence and use, in some cases there 

may be overlap in measures for the 

species or stock and for use of habitat. 

NMFS considers available 

information indicating the likelihood of 

any measure to accomplish its objective. 

If evidence shows that a measure has 

not typically been effective nor 

successful, then either that measure 

should be modified or the potential 

value of the measure to reduce effects 

should be lowered. 

2. Practicability 

Factors considered may include those 

costs, impact on activities, personnel 

safety, and practicality of 

implementation. 

In carrying out the MMPA’s mandate 

for this action, NMFS applies the 

previously described context-specific 

balance between the manner in which 

and the degree to which measures are 

expected to reduce impacts to the 

affected species or stocks and their 

habitat and practicability for operators. 

The effects of concern (i.e., those with 

the potential to adversely impact 

species or stocks and their habitat), 

addressed previously in the Potential 

Effects of the Specified Activity on 

Marine Mammals and Their Habitat 

section of the notice of proposed IHA, 

include auditory injury, severe 

behavioral reactions, disruptions of 

critical behaviors, and to a lesser degree, 

masking and impacts on acoustic 

habitat. Here, we focus on measures 

with proven or reasonably presumed 

ability to avoid or reduce the intensity 

of acute exposures that have potential to 

result in these anticipated effects with 

an understanding of the drawbacks or 

costs of these requirements, as well as 

time-area restrictions that would avoid 

or reduce both acute and chronic 

impacts. To the extent of the 

information available to NMFS, we 

considered practicability concerns, as 

well as potential undesired 

consequences of the measures, e.g., 

extended periods using the acoustic 

source due to the need to reshoot lines. 

NMFS also recognizes that 

instantaneous protocols, such as 

shutdown requirements, are not capable 

of avoiding all acute effects, and are not 

suitable for avoiding many cumulative 

or chronic effects and do not provide 

targeted protection in areas of greatest 

importance for marine mammals. 

Therefore, in addition to a basic suite of 

seismic mitigation protocols, we also 

consider measures that may or may not 

be appropriate for other activities (e.g., 

survey plan modifications specific to 

the action discussed herein), but that are 

warranted here given the potential for 

impacts to a stock of particular concern 

(i.e., Southern Resident killer whales) 

(see Negligible Impact Analysis and 

Determination), and the information we 

have regarding habitat for certain 

species. 

We appreciate the ENGOs suggestions 

for additional mitigation and monitoring 

29100 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

requirements. However, we note that 

many of the recommendations require a 

scale of effort that is not commensurate 

to the scale of either the underlying 

activities or the anticipated impacts of 

the activities on marine mammals 

covered by this authorization. In other 

words, many of the recommended 

measures would necessitate complex 

and expensive survey designs and 

methods that are not reasonable in the 

context of an activity that consists of 

one mobile source moving across a large 

area and that will last for only 37 days. 

As described in the Mitigation Measures 

Considered but Eliminated section of 

this notice, out of concern for the status 

of Southern Resident killer whales and 

proposed critical habitat, NMFS 

considered implementing a closure area 

and prohibiting L–DEO from conducting 

survey operations between the 200-m 

isobath and the coastline. However, as 

the main goal of L–DEO’s survey is to 

examine the geologic features of the 

Cascadia subduction zone along the 

coastal shelf, NMFS determined that 

this exclusion would not be practicable. 

NMFS did ultimately incorporate 

mitigation measures that are specific to 

this action and beyond that which is 

typically required for L–DEO’s surveys. 

Specifically, we have required L–DEO to 

revise their proposed tracklines to avoid 

surveying in waters less than 100 m 

deep in areas with highest estimated 

Southern Resident killer whale 

occurrence. We have determined this 

measure, which will significantly 

reduce impacts to Southern Resident 

killer whales while allowing L–DEO to 

complete its survey objectives, to be 

practicable. Additionally, L–DEO must 

use a second vessel traveling ahead of 

the R/V Langseth with additional PSOs 

to increase the likelihood of detecting 

Southern Resident killer whales and, 

therefore, allowing for greater efficacy in 

implementing shutdown procedures to 

minimize impacts to animals that may 

be in the area. Regardless of whether 

other monitoring plans suggested by the 

ENGOs would also suffice, NMFS has 

determined that the mitigation and 

monitoring required as part of this 

authorization meets the MMPA 

requirement for least practicable adverse 

impact. 

Comment 13: The ENGOs suggested 

NMFS should work with L–DEO and 

explore ways to conduct the survey 

without ensonifying designated and 

proposed Southern Resident killer 

whale critical habitat, or at minimum, 

prohibit ramp-up in the proposed and 

designated critical habitat unless the 

location of all three pods of Southern 

Resident killer whales is known to be 

within the Salish Sea or in an area not 

impacted by survey activity on each day 

of the survey. 

Response: As discussed above, NMFS 

considered prohibiting L–DEO from 

operating within the proposed critical 

habitat for Southern Resident killer 

whales, but determined that the 

exclusion was not practicable, as it 

would prevent L–DEO from completing 

their survey objectives. NMFS has 

worked with L–DEO to revise the survey 

tracklines to avoid ensonifying waters 

less than 100 m deep above the Level B 

harassment threshold, between 

Tillamook Head, Oregon and Barkley 

Sound, British Columbia. As stated 

above, this area contains the highest 

estimated density of Southern Resident 

killer whales. NMFS has not required L– 

DEO to confirm the location of Southern 

Resident killer whales before beginning 

survey activities each day as the 

location of all three pods is often 

unknown and waiting for confirmation 

would not allow L–DEO to complete 

their research objectives. L–DEO is 

required to contact several entities 

(including NMFS, Canada’s DFO, Orca 

Network, and the Whale Museum) on 

each day of the survey to obtain any 

recent reports of Southern Resident 

killer whales in the survey area. 

Comment 14: The ENGOs suggested 

NMFS should consider closures or 

limits on survey activity in proposed 

humpback whale critical habitat and 

biologically important areas for blue 

whales. 

Response: The revised tracklines 

mentioned above, while primarily 

intended to avoid areas of highest 

Southern Resident killer whale 

occurrence, also reduce survey 

tracklines in recently finalized 

humpback whale critical habitat (86 FR 

21082; April 21, 2021) and BIAs for 

humpback whales and other marine 

mammals (we note that no BIAs for blue 

whales have been identified in the 

survey area). Eliminating all tracklines 

in humpback whale critical habitat 

would prevent L–DEO from completing 

their research objectives, as the 

proposed critical habitat occupies most 

of the continental shelf area off of the 

west coast of the U.S., the key area for 

L–DEO’s research. Additionally, the 

ENGOs do not provide any substantive 

reasoning for why prohibiting L–DEO 

from operating within humpback whale 

critical habitat or BIAs is warranted. As 

discussed in the Negligible Impact 

Analysis and Determination section of 

this notice, L–DEO’s activity is not 

expected to have a lasting physical 

impact on humpback whale critical 

habitat, prey within it, or overall 

humpback whale fitness. 

Comment 15: In addition to vesselbased passive acoustic monitoring 

(PAM), the ENGOs suggested NMFS 

should require the use of existing 

moored passive acoustic monitoring 

systems and installation of temporary 

hydrophones or sonabuoys in the survey 

area to monitor marine mammal 

presence. 

Response: NMFS appreciates the 

suggestions regarding increasing 

acoustic monitoring. However, the 

existing network of acoustic recorders 

along the Washington coast is 

comprised of archival recorders, which 

are not monitored in real-time. While 

the deployment of temporary 

hydrophones and sonabuoys in the 

survey area may aid in detection and 

monitoring of marine mammals, NMFS 

does not expect that any additional 

protection would outweigh the cost and 

practicability concerns associated with 

additional personnel required to 

monitor the systems and relay 

detections to the research vessel. The 

use of on-board PAM will adequately 

alert L–DEO of vocalizing marine 

mammals in the immediate vicinity of 

the survey activity. 

Comment 16: The ENGOs 

recommended NMFS should require the 

use of a support vessel traveling ahead 

of the R/V Langseth in proposed critical 

habitat for humpback whales and 

biologically important areas (BIAs) for 

other cetaceans. 

Response: The support vessel 

referenced by the ENGOs is required to 

travel approximately 5 km ahead of the 

R/V Langseth while surveying in waters 

200 m or less between Tillamook Head, 

Oregon and Barkley Sound, British 

Columbia (see Mitigation section of this 

notice). This area encompasses much of 

the critical habitat for humpback whales 

and biologically important areas for 

other species (e.g., gray whale BIA for 

migration). The area of the humpback 

whale critical habitat expected to be 

surveyed on a given day is only a small 

portion of the overall critical habitat 

along the coast. Any impacts to marine 

mammals in this area are expected to be 

minor and temporary, and any 

additional protection that may be 

provided by requiring L–DEO to use the 

support vessel outside of the 200-m 

isobath is not warranted in the context 

of the expected effects and practicability 

concerns. 

Comment 17: The ENGOs suggested 

NMFS should prohibit survey activity in 

low-visibility conditions. 

Response: NMFS disagrees that 

survey activity should be prohibited in 

low-visibility conditions. Any 

requirement to cease operations during 

low visibility conditions, including at 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29101 

night, would not only be impracticable, 

it would also likely result in greater 

impacts to marine mammals, as such a 

measure would require operations to 

continue for significantly more time, to 

make up for lost operations during lowvisibility times. Ramp-up of the acoustic 

source, when necessary, may occur at 

times of poor visibility (including 

nighttime), assuming that a preclearance period has been observed. If 

the pre-clearance period occurs at 

nighttime, the pre-clearance watch 

would be conducted only by the 

acoustic observer. 

Comment 18: The ENGOs suggested 

NMFS should consider whether aerial 

observations would have less impact 

(than the support vessel). 

Response: Similar to the suggestion of 

deploying additional PAM systems 

above, NMFS has determined it is not 

practicable to require L–DEO to use 

aerial monitoring systems. NMFS does 

not expect that any additional 

protection would outweigh the cost and 

practicability of additional personnel 

required to monitor the systems and 

relay detections to the research vessel. 

Comment 19: The ENGOs suggested 

the 1,500-meter exclusion zone, which 

is required for beaked whales, should 

apply for other marine mammal species 

that they suggest are particularly 

sensitive — such as harbor porpoises, 

Steller sea lions, baleen whales (except 

gray whales) and Southern Resident 

killer whales. The commenters suggest 

that the presence of Southern Residents 

should trigger a shut-down whenever 

they are detected, regardless of distance. 

Response: NMFS disagrees that a 

larger standard exclusion zone is 

warranted for the species and groups 

suggested by the ENGOs. The standard 

exclusion zone for all marine mammals 

included in the IHA is 500 m, with 

larger exclusion zones or shutdown 

requirements for certain species and/or 

scenarios. NMFS’ intent in prescribing a 

standard exclusion zone distance is to 

(1) encompass zones for most species 

within which auditory injury could 

occur on the basis of instantaneous 

exposure; (2) provide additional 

protection from the potential for more 

severe behavioral reactions (e.g., panic, 

antipredator response) for marine 

mammals at relatively close range to the 

acoustic source; (3) provide consistency 

and ease of implementation for 

protected species observers (PSOs), who 

need to monitor and implement the 

exclusion zone; and (4) define a 

distance within which detection 

probabilities are reasonably high for 

most species under typical conditions. 

The use of 500 m as the zone is not 

based directly on any quantitative 

understanding of the range at which 

auditory injury would be entirely 

precluded or any range specifically 

related to disruption of behavioral 

patterns. Rather, NMFS believes it is 

based on a reasonable combination of 

factors. In summary, a practicable 

criterion such as this has the advantage 

of familiarity and simplicity while still 

providing in most cases a zone larger 

than relevant auditory injury zones, 

given realistic movement of source and 

receiver. Increased shutdowns, without 

a firm idea of the outcome the measure 

seeks to avoid, simply displace survey 

activity in time and increase the total 

duration of acoustic influence as well as 

total sound energy in the water, which 

NMFS seeks to avoid. In keeping with 

the four broad goals outlined above, and 

in context of the information given here, 

the standard 500-m exclusion zone is 

appropriate. The ENGOs do not provide 

any substantive reasoning for a larger 

zone. 

The proposed IHA included the 

requirement to shut down the airgun 

array if killer whales (of any ecotype) 

are visually or acoustically detected at 

any distance and NMFS has retained 

this requirement in the final 

authorization. 

Comment 20: The ENGOs suggested 

NMFS should require L–DEO to use the 

lowest practicable source level for 

airgun usage. 

Response: L–DEO has selected the 

equipment necessary to achieve their 

research objectives. We have evaluated 

the specified activity as defined by the 

applicant, including changes agreedupon with NMFS in order to provide 

additional protection for Southern 

Resident killer whales, and made the 

necessary findings to authorize taking of 

marine mammals incidental to L–DEO’s 

survey activities. We also note that an 

expert panel was convened by the 

Bureau of Ocean Energy Management to 

determine whether it would be feasible 

to develop standards to determine a 

lowest practicable source level. The 

panel determined that it would not be 

reasonable or practicable to develop 

such metrics (see Appendix L in BOEM, 

2017). 

Comment 21: The ENGOs suggested 

NMFS should require in situ sound 

source verification to determine 

accurate exclusion zones. Similarly, the 

Commission recommended NMFS 

require L–DEO analyze the data 

recorded on the OBSs and OBNs to 

determine the extents of the Level B 

harassment zones in shallow-, 

intermediate-, and deep-water depths 

and specify how the in-situ zones 

compare to the Level B harassment 

zones specified in the final 

authorization. 

Response: As stated above, the 

exclusion zones are not necessarily 

based on specific acoustic parameters, 

thus sound source verification is not 

necessary in the context of exclusion 

zones. Regarding the Commission’s 

recommendation to conduct analysis of 

OBS data, L–DEO has not previously 

undertaken the type of analysis 

suggested by the Commission, and 

indicated to NMFS that it does not have 

the expertise or capability to do so at 

this time. In addition, we note that the 

Commission’s recommendation is 

vague; detailed direction would be 

needed from the Commission on how to 

accomplish the recommended effort. 

This would need to include agreement 

on the analytical approach in order to 

meet expectations and to ensure 

acceptance of results. The Commission’s 

recommendation does not acknowledge 

the time it would take to perform the 

analysis or the level of effort and cost 

that would be involved, e.g., experts 

needed to obtain and review data, 

performing detailed comparative 

analysis, preparation of a report. Based 

on these concerns, NMFS believes that 

the recommendation is not practicable. 

Also, implementation of this 

recommendation would not provide any 

additional conservation value (e.g., 

improvement in mitigation 

effectiveness) for the proposed survey. 

The analysis would be retrospective and 

could be used to help inform analysis of 

future surveys in the same area. NSF is 

considering funding a survey of the 

Queen Charlotte Fault, north of the 

planned survey area for this action, but 

the survey would be completed before 

the acoustic data from this survey 

suggested by the Commission could be 

analyzed. NMFS is not aware of any 

other NSF-proposed seismic surveys on 

the R/V Langseth for this region in the 

foreseeable future that could incorporate 

the in situ data, if analyzed. 

Comment 22: The ENGOs suggested 

NMFS should prohibit the use of the 

Kongsberg Simrad 122 MBES in shallow 

water because the system’s lower 

frequencies were designed for use in 

deeper water. 

Response: The ENGOs provide no 

justification for prohibiting the use of 

the MBES in shallow water aside from 

describing its characteristics. As 

discussed in previous comment 

responses, NMFS has determined the 

MBES is not likely to result in take of 

marine mammals and has no reason to 

believe that the use of the Kongsberg 

Simrad 122 in shallow water is cause for 

concern. The ENGOs do not provide any 

substantive argument to the contrary. 

29102 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

Comment 23: The ENGOs suggested 

NMFS should require L–DEO to 

immediately cease survey activities if 

any authorized take limits are exceeded 

or if a take of an unauthorized species 

occurs (e.g., take of a North Pacific right 

whale). 

Response: NMFS agrees with the 

ENGOs that L–DEO must shut down the 

airgun array if a marine mammal species 

for which take was not authorized, or a 

species for which authorization was 

granted but the takes have been met, 

approaches the Level A or Level B 

harassment zones. This requirement was 

included in the notice of proposed IHA 

but was inadvertently omitted from the 

draft IHA. The final authorization 

includes this requirement. 

Comment 24: The ENGOs suggested 

NMFS should require L–DEO to 

immediately cease survey activities if a 

take of an unauthorized level or 

intensity occurs, (e.g., serious injury or 

mortality of any species or take of a 

Southern Resident killer whale by Level 

A harassment). The ENGOs further 

suggest that if take is found to have been 

exceeded, then there should be an 

investigation and additional mitigation 

to avoid any additional take before 

activities can resume. Similarly, the 

Commission recommended NMFS 

include in all draft and final 

authorizations an explicit requirement 

to cease activities if a marine mammal 

is injured or killed during the specified 

activities, including by vessel strike, 

until NMFS reviews the circumstances 

involving any injury or death that is 

likely attributable to the activities and 

determines what additional measures 

are necessary to minimize additional 

injuries or death. 

Response: NMFS does not expect that 

the proposed activities have the 

potential to result in injury or mortality 

to marine mammals and therefore does 

not agree that a blanket requirement for 

project activities to cease would be 

warranted. NMFS does not agree that a 

requirement for a vessel that is 

operating on the open water to suddenly 

stop operating is practicable, and it is 

unclear what mitigation benefit would 

result from such a requirement in 

relation to vessel strike. The 

Commission does not suggest what 

measures other than those prescribed in 

this IHA would potentially prove more 

effective in reducing the risk of strike. 

Therefore, we have not included this 

requirement in the authorization. NMFS 

retains authority to modify the IHA and 

cease all activities immediately based 

on a vessel strike and will exercise that 

authority if warranted. 

With respect to the Commission’s 

recommendation that NMFS include 

these requirements in all proposed and 

final IHAs, NMFS determines the 

requirements for mitigation measures in 

each authorization based on numerous 

case-specific factors, including 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. As NMFS 

must make these determinations on a 

case by case basis, we therefore do not 

agree with this recommendation. 

Comment 25: The ENGOs suggested 

NMFS impose a ship speed limit of 10 

knots or less at all times to reduce noise 

and prevent ship strikes, with an 

exception for rare emergency or safety 

necessities. While the vessel conducting 

the survey is likely to be traveling well 

under 10 knots, NMFS should make this 

a requirement of any crew-transfer 

vessels used in the project. 

Response: NMFS has analyzed the 

potential for ship strike resulting from 

L–DEO’s planned activity and has 

determined that the mitigation measures 

specific to ship strike avoidance are 

sufficient to avoid the potential for ship 

strike. These include: A requirement 

that all vessel operators reduce vessel 

speed to 10 knots (18.5 km/hour) or less 

when any large whale, any mother/calf 

pairs, pods, or large assemblages of nondelphinoid cetaceans are observed 

within 100 m of an underway vessel; a 

requirement that all survey vessels 

maintain a separation distance of 100 m 

or greater from all large whales, and 500 

m or greater from any sighted North 

Pacific right whale (if a whale is 

observed but cannot be confirmed as a 

species other than a right whale, the 

vessel operator must assume that it is a 

right whale and take appropriate 

action); a requirement that if protected 

species are sighted while a vessel is 

underway, the vessel must take action 

as necessary to avoid violating the 

relevant separation distance (e.g., 

attempt to remain parallel to the 

animal’s course, avoid excessive speed 

or abrupt changes in direction until the 

animal has left the area); and a 

requirement that if marine mammals are 

sighted within the relevant separation 

distance, the vessel must reduce speed 

and shift the engine to neutral, not 

engaging the engines until animals are 

clear of the area. Finally, we note that 

all crew will be aboard the R/V Langseth 

through the entire survey, and there will 

not be any crew transfer vessels. We 

have determined that the ship strike 

avoidance measures are sufficient to 

ensure the least practicable adverse 

impact on species or stocks and their 

habitat and therefore we do not include 

the 10 knot ship speed limit 

recommended by the ENGOs. 

Comment 26: The ENGOs 

recommended NMFS require L–DEO to 

minimize the use of lines and cables 

and ensure that they are not flexible to 

reduce entanglement risk. 

Response: As discussed in the notice 

of proposed IHA, no incidents of 

entanglement of marine mammals with 

seismic survey gear have been 

documented in over 54,000 nautical 

miles (nmi; 100,000 km) of previous 

NSF-funded seismic surveys when 

observers were aboard (e.g., Holst and 

Smultea 2008; RPS 2019; RPS 2021). 

Although entanglement with the 

streamer is theoretically possible, it has 

not been documented during tens of 

thousands of miles of NSF-sponsored 

seismic cruises or, to our knowledge, 

during hundreds of thousands of miles 

of industrial seismic cruises. 

Entanglement in OBSs and OBNs is also 

not expected to occur. There are a 

relative few deployed devices, and no 

interaction between marine mammals 

and any such device has been recorded 

during prior NSF surveys using the 

devices. There are no meaningful 

entanglement risks posed by the 

proposed survey, and therefore although 

we encourage L–DEO to use lines and 

cables that minimize entanglement risk, 

NMFS has not included the 

recommended requirement as a 

condition in the final authorization. 

Comment 27: The ENGOs state that 

marine mammal strandings are most 

likely to result when a sound source is 

moving directly toward the shore. 

Therefore, the ENGOs suggested NMFS 

should require reconfigured tracklines 

to avoid these approaches when the 

airguns are firing. 

Response: There is no conclusive 

evidence that exposure to airgun noise 

results in behaviorally-mediated forms 

of injury (i.e., mass stranding events). 

Behaviorally-mediated injury has been 

primarily associated with beaked 

whales exposed to mid-frequency active 

(MFA) naval sonar. As described in the 

notice of proposed IHA, tactical sonar is 

very different from the noise produced 

by airguns. One should therefore not 

expect the same reaction to airgun noise 

as to these other sources. The ENGOs 

reference a survey conducted by L–DEO 

in 2002 that was contemporaneous with 

and reasonably associated spatially with 

the stranding of two Cuvier’s beaked 

whales. However, the event was not 

considered a ‘‘true atypical mass 

stranding’’ (according to Frantzis (1998)) 

as used in the analysis of Castellote and 

Llorens (2016). While we agree with the 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29103 

authors that this lack of evidence should 

not be considered conclusive, it is clear 

that there is very little evidence that 

seismic surveys should be considered as 

posing a significant risk of acute harm 

to beaked whales or other midfrequency cetaceans. Although NMFS 

does not expect that stranding is a 

potential outcome of this survey 

activity, we also note that certain 

tracklines closest to shore (i.e., in waters 

less than 100 m deep in areas with 

highest estimated Southern Resident 

killer whale occurrence) have been 

eliminated, further reducing the risk of 

this outcome. We have considered the 

potential for the proposed surveys to 

result in marine mammal stranding and 

have concluded that, based on the best 

available information, stranding is not 

expected to occur. Therefore, we have 

not adopted the ENGOs 

recommendation to reconfigure the 

survey tracklines. 

Comment 28: Both the ENGOs and 

Commission object to NMFS’ potential 

consideration of a renewal IHA for this 

action, and in general. The ENGOs 

assert that IHA renewals are not 

permissible under the MMPA and 

instead recommend that applicants 

request a multi-year permit and 

accordingly reevaluate the effects of the 

action based on multiple years of take. 

The Commission recommended NMFS 

refrain from issuing IHA renewals for 

any authorization and instead use an 

abbreviated Federal Register notice 

process, which is similarly expeditious 

and fulfills NMFS’ intent to maximize 

efficiencies. If NMFS continues to 

propose to issue IHA renewals, the 

Commission recommends that NMFS (1) 

stipulate that a renewal is a one-time 

opportunity (a) in all Federal Register 

notices requesting comments on the 

possibility of a renewal, (b) on its web 

page detailing the renewal process, and 

(c) in all draft and final authorizations 

that include a term and condition for a 

renewal and (2) if NMFS declines to 

adopt this recommendation, explain 

fully its rationale for not doing so. 

Response: NMFS’ IHA renewal 

process meets all statutory 

requirements. All IHAs issued, whether 

an initial IHA or a renewal IHA, are 

valid for a period of not more than one 

year. In addition, the public has at least 

30 days to comment on all proposed 

IHAs, with a cumulative total of 45 days 

for IHA renewals. As noted above, the 

Request for Public Comments section of 

the notice of proposed IHA made clear 

that the agency was seeking comment 

on both the initial proposed IHA and 

the potential issuance of a renewal for 

this project. Because any renewal (as 

explained in the Request for Public 

Comments section of the notice of 

proposed IHA) is limited to another year 

of identical or nearly identical activities 

in the same location (as described in the 

Description of Proposed Activity 

section) or the same activities that were 

not completed within the 1 year period 

of the initial IHA, reviewers have the 

information needed to effectively 

comment on both the immediate 

proposed IHA and a possible 1 year 

renewal, should the IHA holder choose 

to request one in the coming months. 

While there will be additional 

documents submitted with a renewal 

request, for a qualifying renewal these 

will be limited to documentation that 

NMFS will make available and use to 

verify that the activities are identical to 

those in the initial IHA, are nearly 

identical such that the changes would 

have either no effect on impacts to 

marine mammals or decrease those 

impacts, or are a subset of activities 

already analyzed and authorized but not 

completed under the initial IHA. NMFS 

will also confirm, among other things, 

that the activities will occur in the same 

location; involve the same species and 

stocks; provide for continuation of the 

same mitigation, monitoring, and 

reporting requirements; and that no new 

information has been received that 

would alter the prior analysis. The 

renewal request will also contain a 

preliminary monitoring report, but that 

is to verify that effects from the 

activities do not indicate impacts of a 

scale or nature not previously analyzed. 

The additional 15-day public comment 

period provides the public an 

opportunity to review these few 

documents, provide any additional 

pertinent information and comment on 

whether they think the criteria for a 

renewal have been met. Between the 

initial 30-day comment period on these 

same activities and the additional 15 

days, the total comment period for a 

renewal is 45 days. 

In addition to the IHA renewal 

process being consistent with all 

requirements under section 101(a)(5)(D), 

it is also consistent with Congress’ 

intent for issuance of IHAs to the extent 

reflected in statements in the legislative 

history of the MMPA. Through the 

provision for renewals in the 

regulations, description of the process 

and express invitation to comment on 

specific potential renewals in the 

Request for Public Comments section of 

each proposed IHA, the description of 

the process on NMFS’ website, further 

elaboration on the process through 

responses to comments such as these, 

posting of substantive documents on the 

agency’s website, and provision of 30 or 

45 days for public review and comment 

on all proposed initial IHAs and 

renewals respectively, NMFS has 

ensured that the public ‘‘is invited and 

encouraged to participate fully in the 

agency decision-making process.’’ 

NMFS does not agree with the 

Commission and therefore does not 

adopt the Commission’s 

recommendation that NMFS use an 

abbreviated Federal Register notice 

instead of IHA renewal. NMFS has 

previously provided responses to this 

specific recommendation in multiple 

notices, including 84 FR 52464 (October 

2, 2019). NMFS does agree with the 

Commission’s recommendation that 

NMFS specify that IHA renewals are a 

one-time opportunity in all Federal 

Register notices requesting comments 

on the possibility of an IHA renewal, in 

all associated proposed and final IHAs, 

and on our website. NMFS has specified 

this in the final IHA for L–DEO’s 

activities and has been including this in 

Federal Register notices and proposed 

and final authorizations since last year. 

Comment 29: The ENGOs 

recommended NMFS and L–DEO 

explore whether the proposed research 

could be conducted using alternative 

technologies or approaches that are less 

harmful to marine mammals. More 

broadly, and beyond the scope of this 

action, the ENGOs recommended NMFS 

engage with NSF to invest in research 

that explores alternative technologies. 

Response: NMFS agrees with the 

ENGOs that development and use of 

technologies that reduce the 

environmental impact of geophysical 

surveys is a laudable objective and may 

be warranted in some cases. Alternative 

technologies are in various stages of 

development, and none of the systems 

with the potential to replace airguns as 

a seismic source are currently 

commercially available for use on a 

scale of activity such as that considered 

herein. Although some alternative 

technologies are available now, or will 

be in the next several years, for select 

uses, none are at a stage where they can 

replace airgun arrays outright. However, 

some may be used in select 

environments when commercially 

available. Such technologies may be 

evaluated in the future as they become 

commercially available and on a scale 

commensurate to the need. In summary, 

while we agree that alternative 

technologies may be beneficial, the 

ENGOs do not suggest any specific 

technologies or approaches and the 

suggestion that NMFS engage with NSF 

to research these methods is outside the 

authority provided to NMFS by the 

MMPA. However, NMFS would 

consider participating in related efforts 

29104 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

by the ENGOs or other entities 

interested in these technologies. 

Comment 30: The ENGOs and the 

Commission recommended NMFS 

require L–DEO to use the method 

proposed by the Commission to estimate 

take and apply relevant corrections for 

airgun activity in daylight vs nighttime 

(including dawn and dusk) to better 

estimate the numbers of marine 

mammals taken by Level A and B 

harassment. The Commission further 

recommends that NMFS require L–DEO 

to specify in the final monitoring report 

(1) the number of days on which the 

airgun array was active and (2) the 

percentage of time and total time the 

array was active during daylight vs 

nighttime hours (including dawn and 

dusk). 

Response: NMFS appreciates the 

Commission’s development of a 

recommended approach to better 

estimate the numbers of marine 

mammals that may have been taken 

during geophysical survey activities, 

including marine mammals that were 

not detected. The ‘‘Commission’s 

method’’ (see the Commission’s letter 

for additional discussion and citation to 

a full description provided in an 

addendum to a May 1, 2019 

Commission comment letter) involves 

correction of marine mammal sightings 

data through use of proxies for marine 

mammal detectability (f (0)) and 

platform/observer bias on marine 

mammal detection (g (0)), and 

extrapolation of corrected marine 

mammal sightings data based on the 

assumed extent of the Level B 

harassment zones. 

However, NMFS does not concur with 

the recommendation to require L–DEO 

to implement this approach because we 

do not have confidence in the reliability 

of estimates of potential marine 

mammal take that would result from use 

of the approach. The Commission does 

not address the multiple assumptions 

that must be made in order to have 

confidence in the estimates that would 

be produced through application of the 

method. For example, the assumption 

that the application of proxy values for 

g (0) and f (0) is appropriate is not 

justified (including application of f (0) 

values to species for which no value is 

available and assuming that application 

of f (0) to species in a wholly different 

region is appropriate). Notably, g (0) 

values are typically derived on a 

platform-specific basis, and even for 

specific observers—not generalized 

across platforms, as the Commission’s 

method would require. 

Separately, the appropriate 

application of distance sampling 

methods requires that certain 

assumptions are valid, and the 

Commission does not explain why these 

assumptions should be assumed to be 

valid during a seismic survey, as 

compared with typical line-transect 

surveys operating without an active 

acoustic source. For example, a key 

underlying concept of distance 

sampling methodology is that the 

probability of detecting an animal 

decreases as its distance from the 

observer increases. This cannot be 

assumed true during an active seismic 

survey. NMFS believes it unlikely that 

the numerous assumptions inherent to 

application of the Commission’s method 

would be accepted in a research context 

(where distance sampling approaches 

are typically applied). 

Furthermore, the area over which 

observations are to be extrapolated 

through the Commission’s method is a 

modeled ensonified area. We do not 

believe it appropriate to assume a 

modeled ensonified area is always 

accurate for purposes of estimating total 

take. In purporting to estimate total 

takes, the method ignores the fact that 

marine mammals exposed to a level of 

received sound assumed to cause take 

for analytical purposes may not in fact 

respond behaviorally in a way that 

equates to take, especially at great 

distance from the source. 

NMFS believes it is important to focus 

on collection and reporting of empirical 

data that can directly inform an 

assessment of the effects of a specified 

activity on the affected species or stock. 

While there may be value in an 

assessment of potential unobserved 

take, we need to proceed cautiously in 

the development of derived values given 

our low confidence in multiple inputs. 

NMFS is currently more broadly 

evaluating monitoring requirements, 

including data collection, interpretation, 

and reporting, as well as the specific 

issue the Commission has raised, and is 

committed to developing improved 

approaches. 

NMFS does concur with the 

Commission’s recommendation that 

NMFS require L–DEO to specify in the 

final monitoring report (1) the number 

of days on which the airgun array was 

active and (2) the percentage of time and 

total time the array was active during 

daylight vs nighttime hours (including 

dawn and dusk). This requirement has 

been added to the final authorization. 

Comment 31: The Commission asserts 

that L–DEO and other NSF-affiliated 

entities have not complied with all of 

the requirements set forth in certain 

final IHAs, and recommends that, 

should the alleged shortcomings occur 

again, NMFS refrain from issuing any 

further authorizations to L–DEO and 

other NSF-affiliated entities until such 

time that the monitoring reports include 

all of the required information. 

Response: NMFS appreciates the 

Commission’s concern and will 

consider any future requests for 

incidental take authorization from NSFaffiliated entities according to the 

requirements of the MMPA. 

Comment 32: Noting its disagreement 

with L–DEO’s approach to estimating 

the size of various ensonified areas, the 

Commission recommends that NMFS 

require L–DEO to either (1) re-estimate 

the proposed Level A and B harassment 

zones and associated takes of marine 

mammals using (a) both operational and 

site-specific environmental parameters, 

(b) what the Commission believes to be 

a comprehensive source model and (c) 

what the Commission believes to be an 

appropriate sound propagation model 

for the proposed IHA or (2) collect or 

provide the relevant acoustic data to 

substantiate that its modeling approach 

is conservative for both deep- and 

intermediate-water depths beyond the 

Gulf of Mexico. In addition, the 

Commission recommends that NMFS (1) 

explain why sound channels with 

downward refraction, as well as seafloor 

reflections, are not likely to occur 

during the geophysical survey, (2) 

specify the degree to which both of 

those parameters would affect the 

estimation (or underestimation) of Level 

B harassment zones in deep- and 

intermediate- water depths, (3) explain 

why L–DEO’s model and other 

modeling approaches provide more 

accurate, realistic, and appropriate 

Level A and B harassment zones than 

BELLHOP (a different propagation 

model favored by the Commission), 

particularly for deep- and intermediatewater depths, and (4) explain why, if L– 

DEO’s model and other modeling 

approaches are considered best 

available science, other action 

proponents that conduct seismic 

surveys are not implementing similar 

methods, particularly given their 

simplicity. 

Response: As noted by the 

Commission, these comments reflect a 

longstanding disagreement between 

NMFS and the Commission regarding 

L–DEO’s approach to modeling the 

output of their airgun array and its 

propagation through the water column. 

NMFS has previously responded to 

similar Commission comments on L– 

DEO’s modeling approach. We refer the 

reader to previous Federal Register 

notices providing responses rather than 

repeat them here (e.g., 84 FR 60059, 

November 07, 2019; 84 FR 54849, 

October 11, 2019; 84 FR 35073, July 22, 

2019). Regardless of the addition of 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29105 

slightly different points or modifications 

to the language with which the 

Commission expresses these points, the 

gist of the Commission’s disagreement 

with L–DEO’s modeling approach 

remains the same. NMFS believes that 

its prior responses have adequately 

explained the rationale for not following 

the Commission’s recommendations 

and, importantly, why L–DEO’s 

modeling approach is adequate. 

Comment 33: The ENGOs asserted 

that NMFS must prepare an 

Environmental Impact Statement and 

cannot rely on the NSF’s Environmental 

Assessment (EA) because they believe 

that there are significant environmental 

impacts. The CBD’s comments on the 

NSF’s draft EA were incorporated by 

reference in the ENGOs’ comment letter 

on the proposed IHA. CBD’s comments 

on NSF’s draft EA primarily concerned 

Southern Resident killer whales, similar 

to the concerns addressed above. 

Response: The NSF’s draft EA, which 

NMFS adopted, was revised in 

consideration of CBD’s comments (and 

those of other public commenters) and 

adequately analyzes the effects of the 

action. The commenters do not provide 

any information to support their claim 

of significant environmental impacts 

under NEPA. NMFS has reviewed the 

NSF’s final EA, determined it to be 

sufficient, and adopted that EA and 

signed a Finding of No Significant 

Impact (FONSI). 

Comment 34: The ENGOs expressed 

doubt that the proposed activities were 

permissible under the ESA because they 

would jeopardize the continued 

existence of Southern Resident killer 

whales, North Pacific right whales, 

humpback whales, and blue whales, 

among other protected species and 

adversely modify proposed critical 

habitat. The proposed action clearly 

affects listed species as well as proposed 

and designated critical habitat, and 

therefore both NMFS and the NSF must 

undergo consultation under the ESA. 

The ENGOs urged NMFS to fulfill our 

commitment to complete consultation 

before authorizing any take of marine 

mammals, and requested a public 

comment period on the products of the 

consultation. The ENGOs strongly 

believe that NMFS cannot authorize the 

specified activities because they will 

jeopardize the recovery and survival of 

Southern Resident killer whales and 

North Pacific right whales. 

Response: NMFS has completed 

consultation under the ESA on our 

proposal to authorize take of listed 

marine mammals incidental to L–DEO’s 

survey activities. The NMFS Office of 

Protected Resources, Interagency 

Cooperation Division issued a Biological 

Opinion concluding that the proposed 

action is not likely to jeopardize the 

continued existence of ESA-listed blue 

whales, fin whales, sei whales, sperm 

whales, Central America DPS humpback 

whales, Mexico DPS humpback whales, 

Southern Resident killer whale DPS, 

and Guadalupe fur seals and is not 

likely to destroy or adversely modify 

Steller sea lion or humpback whale 

critical habitat. There is no designated 

critical habitat in the action area for the 

other listed species. The Interagency 

Cooperation Division determined that a 

public comment period on the 

Biological Opinion was not warranted. 

The final Biological Opinion is available 

on our website at: https://www.fisheries.

noaa.gov/national/marine-mammalprotection/incidental-takeauthorizations-research-and-otheractivities. 

Comment 35: The ENGOs asserted 

that NMFS cannot approve the proposed 

activity without first consulting with the 

states of Washington and Oregon under 

the Coastal Zone Management Act 

(CZMA). The CZMA authorizes states 

with federally approved coastal 

management programs to review 

applications for Federal licenses or 

permits to conduct activities in, or 

outside of, the coastal zone that affects 

land uses, water uses, or natural 

resources within the coastal zone to 

ensure the activity is fully consistent 

with the state’s management plan. 

Response: The NSF submitted 

consistency determinations to 

Washington and Oregon. Both the 

Washington State Department of 

Ecology and Oregon Coastal 

Management Program, the respective 

CZMA authorities for Washington and 

Oregon, concurred with the NSF’s 

determinations. NMFS’ action of 

authorizing take of marine mammal is 

incidental to the NSF’s action of 

conducting the survey, therefore NMFS 

is not required to independently submit 

consistency determinations under 

CZMA. 

Comment 36: The ENGOs and Deep 

Green Wilderness expressed concern 

that the proposed survey overlaps with 

Olympic Coast National Marine 

Sanctuary (OCNMS). The ENGOs 

reference the National Marine 

Sanctuaries Act (NMSA), which aims to 

maintain the natural biological 

communities in the national marine 

sanctuaries, and to protect, and, where 

appropriate, restore and enhance natural 

habitats, populations, and ecological 

processes. To achieve these purposes, 

the NMSA requires that Federal agency 

actions internal or external to a national 

marine sanctuary, including private 

activities authorized by licenses, leases, 

or permits that are likely to destroy, 

cause the loss of, or injure any sanctuary 

resource are subject to consultation with 

the Secretary. The ENGOs noted that the 

action agency must follow the 

recommendations of the Secretary to 

avoid injury to any sanctuary resource 

or otherwise act to prevent and mitigate 

damage to such resources. 

Response: NMFS satisfied our 

responsibilities under section 304(d) of 

the NMSA. NMFS and the NSF drafted 

a joint Sanctuary Resource Statement 

(SRS) to consult with the NOAA Office 

of National Marine Sanctuaries (ONMS) 

under the NMSA. ONMS provided two 

recommended alternatives to minimize 

injury and to protect sanctuary 

resources: (1) Limit operations in 

OCNMS to daylight hours only 

regardless of depth; and 2) use of the 

secondary support vessel aiding in 

marine mammal observations 

throughout the entire sanctuary. NMFS 

has included these recommendations in 

the final IHA. 

Changes From the Proposed IHA to 

Final IHA 

There are numerous changes from the 

proposed IHA, starting with the timing 

of the survey. The survey was initially 

proposed to occur in summer 2020 but 

was delayed until summer 2021. Since 

conclusion of the public comment 

period in May 2020, NMFS has 

reviewed newly available information, 

including recent draft Stock Assessment 

Reports, information on relevant 

Unusual Mortality Events, and other 

scientific literature, and incorporated 

this information into our analysis of 

impacts on marine mammals and their 

habitat. 

In addition to the timing changes, the 

survey tracklines have been modified to 

avoid surveying in the areas with the 

highest expected occurrence of 

Southern Resident killer whales. 

Between Tillamook Head, Oregon and 

Barkley Sound, British Columbia, L– 

DEO’s planned tracklines have been 

truncated or removed entirely such that 

the ensonified area does not extend 

within the 100-meter (m) depth contour 

(see Estimated Take section for 

description of the Level B harassment 

zones and ensonified area). In addition 

to removing tracklines in nearshore 

shallow waters along the coast, L–DEO 

also modified tracklines such that the 

ensonified area will not extend within 

Canadian designated Southern Resident 

and Northern Resident killer whale 

critical habitat. Additionally, under 

consultation with Canada DFO, L–DEO 

removed all tracklines in waters 100 m 

or less in Canadian waters. Thus north 

of Tillamook Head, Oregon, no surveys 

29106 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

will occur in waters 100 m or less (see 

Figure 1). Based on informal 

recommendations from the Commission, 

NMFS recalculated the densities of 

Steller sea lions by applying the 

appropriate pup and non-pup growth 

rates of the population in Washington 

and British Columbia. Takes of all 

species and stocks have been 

recalculated using the revised tracklines 

and resulting ensonified areas. 

Additionally, NMFS has revised the 

mitigation requirements regarding use of 

a second support vessel and daylightonly operations in waters 200 m or less. 

The proposed IHA required the use of 

the support vessel and limited 

operations to daylight only along the 

entire survey area in waters 200 m or 

less. In consideration of operational 

practicability, we have revised that 

requirement to apply only between 

Tillamook Head, Oregon and Barkley 

Sound, British Columbia. Based on 

consultation with the Olympic Coast 

National Marine Sanctuary (OCNMS), 

the final IHA requires L–DEO to use the 

support vessel and operate only during 

daylight hours within the OCNMS, 

regardless of water depth. OCNMS has 

also been added to the list of entities L– 

DEO must contact each day to obtain 

sightings reports of Southern Resident 

killer whales in the survey area and, in 

turn, report their own sightings of killer 

whales to the Sanctuary. Finally, as 

recommended by the Commission, we 

have clarified the required elements that 

must be included in L–DEO’s 

monitoring report. 

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/marinemammal-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 survey 

area and summarizes information 

related to the population or stock, 

including regulatory status under the 

MMPA and ESA and potential 

biological removal (PBR), where known. 

For taxonomy, 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 and Alaska SARs. 

All MMPA stock information presented 

in Table 1 is the most recent available 

at the time of publication and is 

available in the 2019 SARs (Caretta et 

al., 2020; Muto et al., 2020) and draft 

2020 SARs (available online at: https:// 

www.fisheries.noaa.gov/national/ 

marine-mammal-protection/draftmarine-mammal-stock-assessmentreports). Where available, abundance 

and status information is also presented 

for marine mammals in Canadian waters 

in British Columbia. 

TABLE 1—MARINE MAMMALS THAT COULD OCCUR IN THE SURVEY AREA

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

strategic 

(Y/N) 1

Stock abundance 

(CV, Nmin, most recent 

abundance 

survey) 2

PBR Annual 

M/SI 3

Order Cetartiodactyla—Cetacea—Superfamily Mysticeti (baleen whales) 

Family Eschrichtiidae: 

Gray whale ..................... Eschrichtius robustus .......... Eastern North Pacific ........... -/-; N 26,960 (0.05, 25,849, 2016) 801 131 

Family Balaenopteridae 

(rorquals): 

Humpback whale ............ Megaptera novaeangliae ..... California/Oregon/Washington.-/-; Y 2,900 (0.05, 2,784, 2014) .... 16.7 >42.1 

Central North Pacific ........... -/-; Y 10,103 (0.30, 7,891, 2006) .. 83 26 

Minke whale ................... Balaenoptera acutorostrata California/Oregon/Washington.-/-; N 636 (0.72, 369, 2014) .......... 3.5 >1.3 

Sei whale ........................ Balaenoptera borealis .......... Eastern North Pacific ........... E/D; Y 519 (0.4, 374, 2014) ............ 0.75 >0.2 

Fin whale ........................ Balaenoptera physalus ........ California/Oregon/Washington.E/D; Y 9,029 (0.12, 8,127, 2014) .... 81 >43.7 

Northeast Pacific ................. E/D; Y 3,168 (0.26, 2,554, 2013) .... 5.1 0.6 

Blue whale ...................... Balaenoptera musculus ....... Eastern North Pacific ........... E/D; Y 1,496 (0.44, 1,050, 2014) .... 1.2 >19.4 

Superfamily Odontoceti (toothed whales, dolphins, and porpoises) 

Family Physeteridae: 

Sperm whale .................. Physeter macrocephalus ..... California/Oregon/Washington.E/D; Y 1,997 (0.57, 1,270, 2014) .... 2.5 0.4 

Family Kogiidae: 

Pygmy sperm whale ....... Kogia breviceps ................... California/Oregon/Washington.-/-; N 4,111 (1.12, 1,924, 2014) .... 19 0 

Dwarf sperm whale ........ Kogia sima ........................... California/Oregon/Washington.-/-; N Unknown (Unknown, Unknown, 2014).Undetermined 0 

Family Ziphiidae (beaked 

whales): 

Cuvier’s beaked whale ... Ziphius cavirostris ................ California/Oregon/Washington.-/-; N 3,274 (0.67, 2,059, 2014) .... 21 <0.1 


I 
Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29107 

TABLE 1—MARINE MAMMALS THAT COULD OCCUR IN THE SURVEY AREA—Continued 

Common name Scientific name Stock 

ESA/ 

MMPA 

status; 

strategic 

(Y/N) 1

Stock abundance 

(CV, Nmin, most recent 

abundance 

survey) 2

PBR Annual 

M/SI 3

Baird’s beaked whale ..... Berardius bairdii ................... California/Oregon/Washington.-/-; N 2,697 (0.6, 1,633, 2014) ...... 16 0 

Mesoplodont beaked 

whales.

Mesoplodon spp. ................. California/Oregon/Washington.-/-; N 3,044 (0.54, 1,967, 2014) .... 20 0.1 

Family Delphinidae: 

Bottlenose dolphin .......... Tursiops truncatus ............... California/Oregon/Washington offshore.-/-; N 1,924 (0.54, 1,255, 2014) .... 11 >1.6 

Striped dolphin ............... Stenella coeruleoalba .......... California/Oregon/Washington.-/-; N 29,211 (0.2, 24,782, 2014) .. 238 >0.8 

Common dolphin ............ Delphinus delphis ................ California/Oregon/Washington.-/-; N 969,861 (0.17, 839,325, 

2014).

8,393 >40 

Pacific white-sided dolphin.Lagenorhynchus obliquidens California/Oregon/Washington.-/-; N 26,814 (0.28, 21,195, 2014) 191 7.5 

British Columbia 4 ................ N/A 22,160 (unknown, 16,522, 

2008).

Unknown Unknown 

Northern right whale dolphin.Lissodelphis borealis ........... California/Oregon/Washington.-/-; N 26,556 (0.44, 18,608, 2014) 179 3.8 

Risso’s dolphin ............... Grampus griseus ................. California/Oregon/Washington.-/-; N 6,336 (0.32, 4,817, 2014) .... 46 >3.7 

False killer whale ........... Pseudorca crassidens ......... N/A ....................................... N/A N/A ....................................... N/A N/A 

Killer whale ..................... Orcinus orca ........................ Offshore ............................... -/-; N 300 (0.1, 276, 2012) ............ 2.8 0 

Southern Resident ............... E/D; Y 73 (N/A, 73, 2019) ............... 0.13 >0.4 

Northern Resident ............... -/-; N 302 (N/A, 302, 2018) ........... 2.2 0.2 

West Coast Transient .......... -/-; N 349 (N/A, 349, 2018) ........... 3.5 0.4 

Short-finned pilot whale Globicephala 

macrorhynchus.

California/Oregon/Washington.-/-; N 836 (0.79, 466, 2014) .......... 4.5 1.2 

Family Phocoenidae (porpoises): 

Harbor porpoise ............. Phocoena phocoena ............ Northern Oregon/Washington Coast.-/-; N 21,487 (0.44, 15,123, 2011) 151 >3.0 

Northern California/Southern 

Oregon.

-/-; N 35,769 (0.52, 23,749, 2011) 475 >0.6 

British Columbia 4 ................ N/A 8,091 (unknown, 4,885, 

2008).

Unknown Unknown 

Dall’s porpoise ....................... Phocoenoides dalli .............. California/Oregon/Washington.-/-; N 25,750 (0.45, 17,954, 2014) 172 0.3 

British Columbia 4 ................ N/A 5,303 (unknown, 4,638, 

2008).

Unknown Unknown 

Order Carnivora—Superfamily Pinnipedia 

Family Otariidae (eared seals 

and sea lions): 

Northern fur seal ............ Callorhinus ursinus .............. Eastern Pacific ..................... -/D; Y 608,143 (0.2, 514,738, 

2018).

11,067 387 

California .............................. -/D; N 14,050 (N/A, 7,524, 2013) ... 451 1.8 

California sea lion .......... Zalophus californianus ......... U.S. ...................................... -/-; N 257,606 (N/A, 233,515, 

2014).

14,011 >321 

Steller sea lion ............... Eumetopias jubatus ............. Eastern U.S. ........................ -/-; N 43,201 (see SAR, 43,201, 

2017).

2,592 113 

British Columbia 4 ................ N/A 4,037 (unknown, 1,100, 

2008).

Unknown Unknown 

Guadalupe fur seal ......... Arctocephalus philippii 

townsendi.

Mexico to California ............. T/D; Y 34,187 (N/A, 31,019, 2013) 1,062 >3.8 

Family Phocidae (earless 

seals): 

Harbor seal ..................... Phoca vitulina ...................... Oregon/Washington Coastal -/-; N Unknown (Unknown, Unknown, 1999).Undetermined 10.6 

British Columbia 4 ................ N/A 24,916 (Unknown, 19,666, 

2008).

Unknown Unknown 

Northern elephant seal ... Mirounga angustirostris ....... California Breeding .............. -/-; N 179,000 (N/A, 81,368, 2010) 4,882 8.8 

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. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. 

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 M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated with estimated 

mortality due to commercial fisheries is presented in some cases. 

4—Best et al. (2015) total abundance estimates for animals in British Columbia based on surveys of the Strait of Georgia, Johnstone Strait, Queen Charlotte 

Sound, Hecate Strait, and Dixon Entrance. These rows represent British Columbia abundance estimates, where available, but do not represent additional stocks. 

5—The California/Oregon/Washington stock of Mesoplodont beaked whales includes six species of beaked whales. Of the six species represented in this stock, 

only Blainville’s beaked whales, Hubbs’ beaked whales, and Stejneger’s beaked whales are expected to be encountered or taken. 

29108 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

All species that could potentially 

occur in the planned survey areas are 

included in Table 1. However, 

additional species have been recorded 

in the specified geographic region but 

are considered sufficiently rare that take 

is not anticipated. The temporal and/or 

spatial occurrence of North Pacific right 

whales (Eubalaena japonica) is such 

that take is not expected to occur, and 

they are not discussed further beyond 

the explanation provided here. Only 82 

sightings of right whales in the entire 

eastern North Pacific were reported 

from 1962 to 1999, with the majority of 

these occurring in the Bering Sea and 

adjacent areas of the Aleutian Islands 

(Brownell et al., 2001). Most sightings in 

the past 20 years have occurred in the 

southeastern Bering Sea, with a few in 

the Gulf of Alaska (Wade et al., 2011). 

Despite many miles of systematic aerial 

and ship-based surveys for marine 

mammals off the coasts of Washington, 

Oregon and California over several 

years, only seven documented sightings 

of right whales were made from 1990 to 

2000 (Waite et al., 2003), and NMFS 

only aware of two documented sightings 

in the area since then. Because of the 

small population size and the fact that 

North Pacific right whales spend the 

summer feeding in high latitudes, the 

likelihood that the planned survey 

would encounter a North Pacific right 

whale is discountable. 

In addition, the Northern sea otter 

(Enhydra lutris kenyoni) may be found 

in coastal waters of the survey area. 

However, sea otters are managed by the 

U.S. Fish and Wildlife Service and are 

not considered further in this document. 

A detailed description of the species 

likely to be affected by L–DEO’s 

geophysical survey, 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 of proposed IHA 

(85 FR 19580; April 7, 2020). Since that 

time, NMFS has published the draft 

2020 SARs with updated abundance, 

PBR, and/or mortality information for 

the Eastern Pacific stock of northern fur 

seals, West Coast Transient stock of 

killer whales, Central North Pacific 

stock of humpback whales, Northeast 

Pacific and California/Oregon/ 

Washington stocks of fin whale, Eastern 

North Pacific Southern Resident stock of 

killer whales, and Eastern North Pacific 

Stock and Pacific Coast Feeding Group 

of gray whales. The relevant information 

for these stocks has been updated in 

Table 1, however the status of these 

species and stocks has not changed; 

therefore detailed descriptions are not 

provided here. Please refer to the 

Federal Register notice of proposed IHA 

for these descriptions. Please also refer 

to NMFS’ website (https://

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

generalized species accounts. 

Biologically Important Areas and 

Critical Habitat 

Biologically Important Areas (BIAs) 

for feeding gray whales along the coasts 

of Washington, Oregon, and California 

have been identified, including northern 

Puget Sound, Northwestern 

Washington, and Grays Harbor in 

Washington, Depoe Bay and Cape 

Blanco and Orford Reef in Oregon, and 

Point St. George in California; most of 

these areas are of importance from late 

spring through early fall (Calambokidis 

et al., 2015). BIAs have also been 

identified for migrating gray whales 

along the entire coasts of Washington, 

Oregon, and California; although most 

whales travel within 10 km from shore, 

the BIAs were extended out to 47 km 

from the coastline (Calambokidis et al., 

2015). The planned survey will occur 

during the late spring/summer feeding 

season, when most individuals from the 

eastern North Pacific stock occur farther 

north. Nonetheless, individual gray 

whales, particularly those from the 

PCFG could be encountered in 

nearshore waters of the project area. 

Prior to 2016, humpback whales were 

listed under the ESA as an endangered 

species worldwide. Following a 2015 

global status review (Bettridge et al., 

2015), NMFS delineated 14 distinct 

population segments (DPS) with 

different listing statuses (81 FR 62259; 

September 8, 2016) pursuant to the ESA. 

The DPSs that occur in U.S. waters do 

not necessarily equate to the existing 

stocks designated under the MMPA and 

shown in Table 1. Because MMPA 

stocks cannot be portioned, i.e., parts 

managed as ESA-listed while other parts 

managed as not ESA-listed, until such 

time as the MMPA stock delineations 

are reviewed in light of the DPS 

designations, NMFS considers the 

existing humpback whale stocks under 

the MMPA to be endangered and 

depleted for MMPA management 

purposes (e.g., selection of a recovery 

factor, stock status). 

Within the survey area, three DPSs 

may occur: The Hawaii DPS (not listed), 

Mexico DPS (threatened), and Central 

America DPS (endangered). On April 

21, 2021, NMFS issued a final rule to 

designate critical habitat in nearshore 

waters of the North Pacific Ocean for the 

endangered Central America DPS and 

the threatened Mexico DPS of 

humpback whale (86 FR 21082). Critical 

habitat for the Central America DPS and 

Mexico DPS was established within the 

California Current Ecosystem (CCE) off 

the coasts California, Oregon, and 

Washington, representing areas of key 

foraging habitat. Off Washington and 

northern Oregon, the critical habitat 

extends from the 50-m isobath out to the 

1200-m isobath; off southern Oregon 

(south of 42°10′ N), it extends out to the 

2000-m isobath. L–DEO’s easternmost 

planned tracklines occur within 

designated humpback whale critical 

habitat along the coast. 

Critical habitat for humpbacks has 

been designated under Canadian law in 

four locations in British Columbia (DFO 

2013), including in the waters of the 

survey area off southwestern Vancouver 

Island. The other three locations are 

located north of the survey area at Haida 

Gwaii (Langara Island and Southeast 

Moresby Island) and at Gil Island (DFO 

2013). These areas show persistent 

aggregations of humpback whales and 

have features such as prey availability, 

suitable acoustic environment, water 

quality, and physical space that allow 

for feeding, foraging, socializing, and 

resting (DFO 2013). A small portion of 

L–DEO’s planned tracklines overlap 

with Canadian designated humpback 

whale critical habitat off southwest 

Vancouver Island. 

BIAs for feeding humpbacks along the 

coasts of Oregon and Washington, 

which have been described from May to 

November, are all within approximately 

80 km from shore, and include the 

waters off northern Washington, and 

Stonewall and Heceta Bank, Oregon 

(Calambokidis et al., 2015). Some 

segments of L–DEO’s planned tracklines 

overlap with these BIAs. 

The U.S. Southern Resident killer 

whale critical habitat designated under 

the ESA currently includes inland 

waters of Washington relative to a 

contiguous shoreline delimited by the 

line at a depth of 6.1 m relative to 

extreme high water (71 FR 69054; 

November 29, 2006). On September 19, 

2019, NMFS published a proposed rule 

to revise designated Southern Resident 

killer whale critical habitat to include 

40,472.7 km2 of marine waters between 

the 6.1-m depth contour and the 200-m 

depth contour from the U.S. 

international border with Canada south 

to Point Sur, California (84 FR 49214; 

September 19, 2019). The planned 

survey tracklines overlap with NMFS’ 

proposed expanded Southern Resident 

critical habitat. 

In Canada, Southern Resident killer 

whales are listed as Endangered under 

the Species at Risk Act (SARA), and 

critical habitat has been designated in 

the trans-boundary waters in southern 

British Columbia, including the 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29109 

southern Strait of Georgia, Haro Strait, 

and Strait of Juan de Fuca (SOR/2018– 

278, December 13, 2018; SOR/2009–68, 

February 19, 2009; DFO 2018). The 

continental shelf waters off 

southwestern Vancouver Island, 

including Swiftsure and La Pe ́rouse 

Banks have also been designated as 

critical habitat for Southern Resident 

and Northern Resident killer whales 

(SOR/2018–278, December 13, 2018). As 

discussed above, L–DEO’s initial 

proposed survey tracklines that 

overlapped with Canadian designated 

critical habitat for killer whales have 

been eliminated. 

Federally designated critical habitat 

for Steller sea lions in Oregon and 

California includes all rookeries (NMFS 

1993). Although the Eastern DPS was 

delisted from the ESA in 2013, the 

designated critical habitat remains valid 

(NOAA 2019e). The critical habitat in 

Oregon is located along the coast at 

Rogue Reef (Pyramid Rock) and Orford 

Reef (Long Brown Rock and Seal Rock). 

The critical habitat area includes 

aquatic zones that extend 0.9 km 

seaward and air zones extending 0.9 km 

above these terrestrial and aquatic zones 

(NMFS 1993). L–DEO’s planned 

tracklines lie about 9 and 13 km away 

from the two Oregon units of Steller sea 

lion critical habitat. 

Unusual Mortality Events 

On May 30, 2019, NMFS declared an 

unusual mortality event (UME) for gray 

whales after elevated numbers of 

strandings occurred along the U.S. west 

coast. As of April 5, 2021, a total of 430 

stranded gray whales have been 

reported, including 209 in the United 

States (93 in Alaska, 50 in Washington, 

9 in Oregon, and 57 in California), 205 

in Mexico, and 16 in Canada. Full or 

partial necropsy examinations were 

conducted on a subset of the whales. 

Preliminary findings in several of the 

whales have shown evidence of 

emaciation. These findings are not 

consistent across all of the whales 

examined, so more research is needed. 

The UME is ongoing, and NMFS 

continues to investigate the cause(s). 

Additional information about the UME 

is available at https://www.fisheries.

noaa.gov/national/marine-life-distress/ 

2019-2020-gray-whale-unusualmortality-event-along-west-coast. 

Increased strandings of Guadalupe fur 

seals have occurred along the entire 

coast of California. Guadalupe fur seal 

strandings began in January 2015 and 

were eight times higher than the 

historical average. Strandings have 

continued since 2015 and have 

remained well above average through 

2019. Strandings are seasonal and 

generally peak in April through June of 

each year. Strandings in Oregon and 

Washington became elevated starting in 

2019 and have continued to present. 

Strandings in these two states in 2019 

are five times higher than the historical 

average. Guadalupe fur seals have 

stranded alive and dead. Those 

stranding are mostly weaned pups and 

juveniles (1–2 years old). The majority 

of stranded animals showed signs of 

malnutrition with secondary bacterial 

and parasitic infections. NMFS has 

declared a UME for Guadalupe fur seals 

along the entire U.S. West Coast; the 

UME is ongoing and NMFS is 

continuing to investigate the cause(s). 

For additional information on the UME, 

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

national/marine-life-distress/2015-2020- 

guadalupe-fur-seal-unusual-mortalityevent-california. 

Elevated strandings of California sea 

lion pups occurred in Southern 

California between January 2013 and 

September 2016. As a result, NMFS 

declared a UME. The UME was confined 

to pup and yearling California sea lions, 

many of which were emaciated, 

dehydrated, and underweight for their 

age. A change in the availability of sea 

lion prey, especially sardines, a high 

value food source for nursing mothers, 

was a likely contributor to the large 

number of strandings. Sardine spawning 

grounds shifted further offshore in 2012 

and 2013, and while other prey were 

available (market squid and rockfish), 

these may not have provided adequate 

nutrition in the milk of sea lion mothers 

supporting pups, or for newly-weaned 

pups foraging on their own. Although 

the pups showed signs of some viruses 

and infections, findings indicate that 

this event was not caused by disease, 

but rather by the lack of high quality, 

close-by food sources for nursing 

mothers. Current evidence does not 

indicate that this UME was caused by a 

single infectious agent, though a variety 

of disease-causing bacteria and viruses 

were found in samples from sea lion 

pups. The investigative team examined 

multiple potential explanations for the 

high numbers of malnourished 

California sea lion pups observed on the 

island rookeries and stranded on the 

mainland in 2013. For more 

information, see https://www.fisheries.

noaa.gov/national/marine-life-distress/ 

2013-2017-california-sea-lion-unusualmortality-event-california. 

Marine Mammal Hearing 

Hearing is the most important sensory 

modality for marine mammals 

underwater, and exposure to 

anthropogenic sound can have 

deleterious effects. To appropriately 

assess the potential effects of exposure 

to sound, it is necessary to understand 

the frequency ranges marine mammals 

are able to hear. Current data indicate 

that not all marine mammal species 

have equal hearing capabilities (e.g., 

Richardson et al., 1995; Wartzok and 

Ketten, 1999; Au and Hastings, 2008). 

To reflect this, Southall et al. (2007) 

recommended that marine mammals be 

divided into functional hearing groups 

based on directly measured or estimated 

hearing ranges on the basis of available 

behavioral response data, audiograms 

derived using auditory evoked potential 

techniques, anatomical modeling, and 

other data. Note that no direct 

measurements of hearing ability have 

been successfully completed for 

mysticetes (i.e., low-frequency 

cetaceans). Subsequently, NMFS (2018) 

described generalized hearing ranges for 

these marine mammal hearing groups. 

Generalized hearing ranges were chosen 

based on the approximately 65 dB 

threshold from the normalized 

composite audiograms, with the 

exception for lower limits for lowfrequency cetaceans where the lower 

bound was deemed to be biologically 

implausible and the lower bound from 

Southall et al. (2007) retained. Marine 

mammal hearing groups and their 

associated hearing ranges are provided 

in Table 2. 

TABLE 2—MARINE MAMMAL HEARING GROUPS (NMFS, 2018) 

Hearing group Generalized hearing range * 

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

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

High-frequency (HF) cetaceans (true porpoises, Kogia, river dolphins, cephalorhynchid, Lagenorhynchus 

cruciger & L. australis).

275 Hz to 160 kHz. 

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

29110 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

TABLE 2—MARINE MAMMAL HEARING GROUPS (NMFS, 2018)—Continued 

Hearing group Generalized hearing range * 

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

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

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

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

The pinniped functional hearing 

group was modified from Southall et al. 

(2007) on the basis of data indicating 

that phocid species have consistently 

demonstrated an extended frequency 

range of hearing compared to otariids, 

especially in the higher frequency range 

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

2009; Reichmuth and Holt, 2013). 

For more detail concerning these 

groups and associated frequency ranges, 

please see NMFS (2018) for a review of 

available information. 31 marine 

mammal species (25 cetacean and six 

pinniped (four otariid and two phocid) 

species) have the reasonable potential to 

co-occur with the planned survey 

activities. Please refer to Table 1. Of the 

cetacean species that may be present, 

six are classified as low-frequency 

cetaceans (i.e., all mysticete species), 15 

are classified as mid-frequency 

cetaceans (i.e., all delphinid and ziphiid 

species and the sperm whale), and four 

are classified as high-frequency 

cetaceans (i.e., porpoises and Kogia 

spp.). 

Potential Effects of Specified Activities 

on Marine Mammals and Their Habitat 

The effects of underwater noise from 

L–DEO’s geophysical survey 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 19580; April 7, 

2020) included a discussion of the 

effects of anthropogenic noise on marine 

mammals and the potential effects of 

underwater noise from L–DEO’s 

geophysical survey 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 19580; April 7, 2020). The 

referenced information includes a 

summary and discussion of the ways 

that the specified activity may impact 

marine mammals and their habitat. 

Consistent with the analysis in our prior 

Federal Register notices for similar L– 

DEO surveys and after independently 

evaluating the analysis in L–DEO’s 

application, we determine that the 

survey is likely to result in the takes 

described in the Estimated Take section 

of this document and that other forms 

of take are not expected to occur. 

The Estimated Take section later in 

this document includes a quantitative 

analysis of the number of individuals 

that are expected to be taken by this 

activity. The Negligible Impact Analysis 

and Determination section considers the 

content of this section, the Estimated 

Take section, and the Mitigation section, 

to draw conclusions regarding the likely 

impacts of these activities on the 

reproductive success or survivorship of 

individuals and how those impacts on 

individuals are likely to impact marine 

mammal species or stocks. 

Description of Active Acoustic Sound 

Sources 

The notice of proposed IHA provided 

a brief technical background on sound, 

on the characteristics of certain sound 

types, and on metrics used in the 

proposal inasmuch as the information 

was relevant to the specified activity 

and to a discussion of the potential 

effects of the specified activity on 

marine mammals found later in this 

document. Please see that document (85 

FR 19580; April 7, 2020) for additional 

information. For general information on 

sound and its interaction with the 

marine environment, please see, e.g., Au 

and Hastings (2008); Richardson et al. 

(1995); Urick (1983). 

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 will primarily be by 

Level B harassment, as use of seismic 

airguns has the potential to result in 

disruption of behavioral patterns for 

individual marine mammals. There is 

also some potential for auditory injury 

(Level A harassment) for mysticetes and 

high frequency cetaceans (i.e., 

porpoises, Kogia spp.). The mitigation 

and monitoring measures are expected 

to minimize the severity of such taking 

to the extent practicable. 

As described previously, no serious 

injury or mortality is anticipated or 

authorized for this activity. Below we 

describe how the take is estimated. 

Generally speaking, we estimate take 

by considering: (1) Acoustic thresholds 

above which NMFS believes the best 

available science indicates marine 

mammals will be behaviorally harassed 

or incur some degree of permanent 

hearing impairment; (2) the area or 

volume of water that will be ensonified 

above these levels in a day; (3) the 

density or occurrence of marine 

mammals within these ensonified areas; 

and, (4) and the number of days of 

activities. We note that while these 

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. 

Acoustic Thresholds 

NMFS uses acoustic thresholds that 

identify the received level of 

underwater sound above which exposed 

marine mammals would be reasonably 

expected to be behaviorally harassed 

(equated to Level B harassment) or to 

incur PTS of some degree (equated to 

Level A harassment). 

Level B Harassment for non-explosive 

sources—Though significantly driven by 

received level, the onset of behavioral 

disturbance from anthropogenic noise 

exposure is also informed to varying 

degrees by other factors related to the 

source (e.g., frequency, predictability, 

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

bathymetry), and the receiving animals 

(hearing, motivation, experience, 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29111 

demography, behavioral context) and 

can be difficult to predict (Southall et 

al., 2007, Ellison et al., 2012). NMFS 

uses a generalized acoustic threshold 

based on received level to estimate the 

onset of behavioral harassment. NMFS 

predicts that marine mammals are likely 

to be behaviorally harassed in a manner 

we consider Level B harassment when 

exposed to underwater anthropogenic 

noise above received levels of 120 dB re 

1 microPascal (mPa) root mean square 

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

mPa (rms) for non-explosive impulsive 

(e.g., seismic airguns) or intermittent 

(e.g., scientific sonar) sources. L–DEO’s 

planned activity includes the use of 

impulsive seismic sources. Therefore, 

the 160 dB re 1 mPa (rms) criteria is 

applicable for analysis of Level B 

harassment. 

Level A harassment for non-explosive 

sources—NMFS’ Technical Guidance 

for Assessing the Effects of 

Anthropogenic Sound on Marine 

Mammal Hearing (Version 2.0) 

(Technical Guidance, 2018) identifies 

dual criteria to assess auditory injury 

(Level A harassment) to five different 

marine mammal groups (based on 

hearing sensitivity) as a result of 

exposure to noise from two different 

types of sources (impulsive or nonimpulsive). L–DEO’s planned seismic 

survey includes the use of impulsive 

(seismic airguns) sources. 

These thresholds are provided in the 

table below. The references, analysis, 

and methodology used in the 

development of the thresholds are 

described in NMFS 2018 Technical 

Guidance, which may be accessed at 

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

national/marine-mammal-protection/ 

marine-mammal-acoustic-technicalguidance. 

TABLE 3—THRESHOLDS IDENTIFYING THE ONSET OF PERMANENT THRESHOLD SHIFT

PTS onset acoustic thresholds *

(received level) 

Hearing group Impulsive Non-impulsive 

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

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

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

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

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

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

also be considered. 

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

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

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

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

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

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

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

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

Ensonified Area 

Here, we describe operational and 

environmental parameters of the activity 

that will feed into identifying the area 

ensonified above the acoustic 

thresholds, which include source levels 

and acoustic propagation modeling. 

L–DEO’s modeling methodology is 

described in greater detail in the IHA 

application (LGL 2019). The planned 2D 

survey will acquire data using the 36- 

airgun array with a total discharge 

volume of 6,600 cubic inches (in3) at a 

maximum tow depth of 12 m. L–DEO 

model results are used to determine the 

160-dBrms radius for the 36-airgun 

array in deep water (≤1,000 m) down to 

a maximum water depth of 2,000 m. 

Water depths in the project area may be 

up to 4,400 m, but marine mammals are 

generally not anticipated to dive below 

2,000 m (Costa and Williams 1999). 

Received sound levels were predicted 

by L–DEO’s model (Diebold et al., 2010) 

which uses ray tracing for the direct 

wave traveling from the array to the 

receiver and its associated source ghost 

(reflection at the air-water interface in 

the vicinity of the array), in a constantvelocity half-space (infinite 

homogeneous ocean layer, unbounded 

by a seafloor). In addition, propagation 

measurements of pulses from the 36- 

airgun array at a tow depth of 6 m have 

been reported in deep water 

(approximately 1600 m), intermediate 

water depth on the slope (approximately 

600–1100 m), and shallow water 

(approximately 50 m) in the Gulf of 

Mexico in 2007–2008 (Tolstoy et al. 

2009; Diebold et al. 2010). 

For deep and intermediate-water 

cases, the field measurements cannot be 

used readily to derive Level A and Level 

B harassment isopleths, as at those sites 

the calibration hydrophone was located 

at a roughly constant depth of 350–500 

m, which may not intersect all the 

sound pressure level (SPL) isopleths at 

their widest point from the sea surface 

down to the maximum relevant water 

depth for marine mammals of ∼2,000 m. 

At short ranges, where the direct 

arrivals dominate and the effects of 

seafloor interactions are minimal, the 

data recorded at the deep and slope sites 

are suitable for comparison with 

modeled levels at the depth of the 

calibration hydrophone. At longer 

ranges, the comparison with the 

model—constructed from the maximum 

SPL through the entire water column at 

varying distances from the airgun 

array—is the most relevant. 

In deep and intermediate-water 

depths, comparisons at short ranges 

between sound levels for direct arrivals 

recorded by the calibration hydrophone 

and model results for the same array 

tow depth are in good agreement (Fig. 

12 and 14 in Appendix H of NSF–USGS, 

2011). Consequently, isopleths falling 

within this domain can be predicted 

reliably by the L–DEO model, although 

they may be imperfectly sampled by 

measurements recorded at a single 

depth. At greater distances, the 

calibration data show that seafloorreflected and sub-seafloor-refracted 

arrivals dominate, whereas the direct 

arrivals become weak and/or 

incoherent. Aside from local topography 

effects, the region around the critical 

distance is where the observed levels 

rise closest to the model curve. 

However, the observed sound levels are 

found to fall almost entirely below the 

29112 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

model curve. Thus, analysis of the Gulf 

of Mexico calibration measurements 

demonstrates that although simple, the 

L–DEO model is a robust tool for 

conservatively estimating isopleths. For 

deep water (>1,000 m), L–DEO used the 

deep-water radii obtained from model 

results down to a maximum water depth 

of 2,000 m. 

A recent retrospective analysis of 

acoustic propagation from use of the 

R/V Langseth sources during a 2012 

survey off Washington (i.e., in the same 

location) suggests that predicted 

(modeled) radii (using the same 

approach as that used here) were 2–3 

times larger than the measured radii in 

shallow water. (Crone et al., 2014). 

Therefore, because the modeled 

shallow-water radii were specifically 

demonstrated to be overly conservative 

for the region in which the current 

survey is planned, L–DEO used the 

received levels from multichannel 

seismic data collected by the R/V 

Langseth during the 2012 survey to 

estimate Level B harassment radii in 

shallow (<100 m) and intermediate 

(100–1,000 m) depths (Crone et al., 

2014). Streamer data in shallow water 

collected in 2012 have the advantage of 

including the effects of local and 

complex subsurface geology, seafloor 

topography, and water column 

properties, and thus allow 

determination of radii more confidently 

than using data from calibration 

experiments in the Gulf of Mexico. 

The survey will acquire data with a 

four-string 6,600-in3 airgun array at a 

tow depth of 12 m while the data 

collected in 2012 were acquired with 

the same airgun array at a tow depth of 

9 m. To account for the differences in 

tow depth between the 2012 survey and 

the planned 2021 survey, L–DEO 

calculated a scaling factor using the 

deep water modeling (see Appendix D 

in L–DEO’s IHA application). A scaling 

factor of 1.15 was applied to the 

measured radii from the airgun array 

towed at 9 m. 

The estimated distances to the Level 

B harassment isopleth for the R/V 

Langseth’s 36-airgun array are shown in 

Table 4. 

TABLE 4—PREDICTED RADIAL DISTANCES TO ISOPLETHS CORRESPONDING TO LEVEL B HARASSMENT THRESHOLD

Source and volume Tow depth 

(m) 

Water depth 

(m) 

Level B 

harassment 

zone (m) 

using L–DEO 

model 

36 airgun array, 6,600-in3 ............................................................................................................ 12 >1000 a 6,733 

100–1000 b 9,468 

<100 b 12,650 

a Distance based on L–DEO model results. 

b Distance based on data from Crone et al. (2014). 

Predicted distances to Level A 

harassment isopleths, which vary based 

on marine mammal hearing groups, 

were calculated based on modeling 

performed by L–DEO using the 

NUCLEUS source modeling software 

program and the NMFS User 

Spreadsheet, described below. The 

acoustic thresholds for impulsive 

sounds (e.g., airguns) contained in the 

Technical Guidance were presented as 

dual metric acoustic thresholds using 

both cumulative sound exposure level 

(SELcum) and peak sound pressure 

metrics (NMFS 2018). As dual metrics, 

NMFS considers onset of PTS (Level A 

harassment) to have occurred when 

either one of the two metrics is 

exceeded (i.e., metric resulting in the 

largest isopleth). The SELcum metric 

considers both level and duration of 

exposure, as well as auditory weighting 

functions by marine mammal hearing 

group. In recognition of the fact that the 

requirement to calculate Level A 

harassment ensonified areas could be 

more technically challenging to predict 

due to the duration component and the 

use of weighting functions in the new 

SELcum thresholds, NMFS developed an 

optional User Spreadsheet that includes 

tools to help predict a simple isopleth 

that can be used in conjunction with 

marine mammal density or occurrence 

to facilitate the estimation of take 

numbers. 

The values for SELcum and peak SPL 

for the R/V Langseth airgun array were 

derived from calculating the modified 

far-field signature (Table 5). The farfield 

signature is often used as a theoretical 

representation of the source level. To 

compute the farfield signature, the 

source level is estimated at a large 

distance below the array (e.g., 9 km), 

and this level is back projected 

mathematically to a notional distance of 

1 m from the array’s geometrical center. 

However, when the source is an array of 

multiple airguns separated in space, the 

source level from the theoretical farfield 

signature is not necessarily the best 

measurement of the source level that is 

physically achieved at the source 

(Tolstoy et al. 2009). Near the source (at 

short ranges, distances <1 km), the 

pulses of sound pressure from each 

individual airgun in the source array do 

not stack constructively, as they do for 

the theoretical farfield signature. The 

pulses from the different airguns spread 

out in time such that the source levels 

observed or modeled are the result of 

the summation of pulses from a few 

airguns, not the full array (Tolstoy et al. 

2009). At larger distances, away from 

the source array center, sound pressure 

of all the airguns in the array stack 

coherently, but not within one time 

sample, resulting in smaller source 

levels (a few dB) than the source level 

derived from the farfield signature. 

Because the farfield signature does not 

take into account the large array effect 

near the source and is calculated as a 

point source, the modified farfield 

signature is a more appropriate measure 

of the sound source level for distributed 

sound sources, such as airgun arrays. L– 

DEO used the acoustic modeling 

methodology as used for Level B 

harassment with a small grid step of 1 

m in both the inline and depth 

directions. The propagation modeling 

takes into account all airgun 

interactions at short distances from the 

source, including interactions between 

subarrays, which are modeled using the 

NUCLEUS software to estimate the 

notional signature and MATLAB 

software to calculate the pressure signal 

at each mesh point of a grid. 

For a more complete explanation of 

this modeling approach, please see 

‘‘Appendix A: Determination of 

Mitigation Zones’’ in the IHA 

application. 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29113 

TABLE 5—MODELED SOURCE LEVELS BASED ON MODIFIED FARFIELD SIGNATURE FOR THE 6,600-IN 3 AIRGUN ARRAY

Low frequency 

cetaceans 

(Lpk,flat: 219 

dB; LE,LF,24h: 

183 dB) 

Mid frequency 

cetaceans 

(Lpk,flat: 230 

dB; LE,MF,24h: 

185 dB 

High 

frequency 

cetaceans 

(Lpk,flat: 202 

dB; LE,HF,24h: 

155 dB) 

Phocid 

pinnipeds 

(underwater) 

(Lpk,flat: 218 

dB; LE,HF,24h: 

185 dB) 

Otariid 

pinnipeds 

(underwater) 

(Lpk,flat: 232 

dB; LE,HF,24h: 

203 dB) 

6,600 in3 airgun array (Peak SPLflat) .................................. 252.06 252.65 253.24 252.25 252.52 

6,600 in3 airgun array (SELcum) ........................................... 232.98 232.84 233.10 232.84 232.08 

In order to more realistically 

incorporate the Technical Guidance’s 

weighting functions over the seismic 

array’s full acoustic band, unweighted 

spectrum data for the R/V Langseth’s 

airgun array (modeled in 1 Hz bands) 

was used to make adjustments (dB) to 

the unweighted spectrum levels, by 

frequency, according to the weighting 

functions for each relevant marine 

mammal hearing group. These adjusted/ 

weighted spectrum levels were then 

converted to pressures (mPa) in order to 

integrate them over the entire 

broadband spectrum, resulting in 

broadband weighted source levels by 

hearing group that could be directly 

incorporated within the User 

Spreadsheet (i.e., to override the 

Spreadsheet’s more simple weighting 

factor adjustment). Using the User 

Spreadsheet’s ‘‘safe distance’’ 

methodology for mobile sources 

(described by Sivle et al., 2014) with the 

hearing group-specific weighted source 

levels, and inputs assuming spherical 

spreading propagation and source 

velocities (4.2 knots) and shot intervals 

(37.5 m) specific to the planned survey, 

potential radial distances to auditory 

injury zones were then calculated for 

SELcum thresholds. 

Inputs to the User Spreadsheets in the 

form of estimated SLs are shown in 

Table 5. User Spreadsheets used by 

L–DEO to estimate distances to Level A 

harassment isopleths for the 36-airgun 

array for the surveys are shown in Table 

A–3 in Appendix A of the IHA 

application. Outputs from the User 

Spreadsheets in the form of estimated 

distances to Level A harassment 

isopleths for the survey are shown in 

Table 6. As described above, NMFS 

considers onset of PTS (Level A 

harassment) to have occurred when 

either one of the dual metrics (SELcum

and Peak SPLflat) is exceeded (i.e., 

metric resulting in the largest isopleth). 

TABLE 6—MODELED RADIAL DISTANCES (M) TO ISOPLETHS CORRESPONDING TO LEVEL A HARASSMENT THRESHOLDS

Source 

(volume) Threshold 

Level A harassment zone (m) 

LF cetaceans MF cetaceans HF cetaceans Phocids Otariids 

36-airgun array (6,600 in3) ................ SELcum .................. 426.9 0 1.3 13.9 0 

Peak ..................... 38.9 13.6 268.3 43.7 10.6 

Note that because of some of the 

assumptions included in the methods 

used (e.g., stationary receiver with no 

vertical or horizontal movement in 

response to the acoustic source), 

isopleths produced may be 

overestimates to some degree, which 

will ultimately result in some degree of 

overestimation of Level A harassment. 

However, these tools offer the best way 

to predict appropriate isopleths when 

more sophisticated 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 mobile sources, such as this seismic 

survey, the User Spreadsheet predicts 

the closest distance at which a 

stationary animal would not incur PTS 

if the sound source traveled by the 

animal in a straight line at a constant 

speed. 

Auditory injury is unlikely to occur 

for mid-frequency cetaceans, otariid 

pinnipeds, and phocid pinnipeds given 

very small modeled zones of injury for 

those species (up to 43.7 m), in context 

of distributed source dynamics. The 

source level of the array is a theoretical 

definition assuming a point source and 

measurement in the far-field of the 

source (MacGillivray, 2006). As 

described by Caldwell and Dragoset 

(2000), an array is not a point source, 

but one that spans a small area. In the 

far-field, individual elements in arrays 

will effectively work as one source 

because individual pressure peaks will 

have coalesced into one relatively broad 

pulse. The array can then be considered 

a ‘‘point source.’’ For distances within 

the near-field, i.e., approximately 2–3 

times the array dimensions, pressure 

peaks from individual elements do not 

arrive simultaneously because the 

observation point is not equidistant 

from each element. The effect is 

destructive interference of the outputs 

of each element, so that peak pressures 

in the near-field will be significantly 

lower than the output of the largest 

individual element. Here, the relevant 

peak isopleth distances for these three 

hearing groups would in all cases be 

expected to be within the near-field of 

the array where the definition of source 

level breaks down. Therefore, actual 

locations within this distance of the 

array center where the sound level 

exceeds the relevant criteria would not 

necessarily exist. In general, Caldwell 

and Dragoset (2000) suggest that the 

near-field for airgun arrays is considered 

to extend out to approximately 250 m. 

For full discussion of these concepts, 

please see our notice of proposed IHA 

(85 FR 19580; April 7, 2020). 

In consideration of the received sound 

levels in the near-field as described 

above, we expect the potential for Level 

A harassment of mid-frequency 

cetaceans, otariid pinnipeds, and 

phocid pinnipeds to be de minimis, 

even before the likely moderating effects 

of aversion and/or other compensatory 

behaviors (e.g., Nachtigall et al., 2018) 

are considered. We do not believe that 

Level A harassment is a likely outcome 

for any mid-frequency cetacean, otariid 

pinniped, or phocid pinniped and have 

not authorized any Level A harassment 

for these species. 

Marine Mammal Occurrence 

In this section we provide the 

information about the presence, density, 

29114 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

and group dynamics of marine 

mammals that will inform the take 

calculations. 

Extensive systematic aircraft- and 

ship-based surveys have been 

conducted for marine mammals in 

offshore waters of Oregon and 

Washington (e.g., Bonnell et al., 1992; 

Green et al., 1992, 1993; Barlow 1997, 

2003; Barlow and Taylor 2001; 

Calambokidis and Barlow 2004; Barlow 

and Forney 2007; Forney 2007; Barlow 

2010). Ship surveys for cetaceans in 

slope and offshore waters of Oregon and 

Washington were conducted by NMFS’ 

Southwest Fisheries Science Center 

(SWFSC) in 1991, 1993, 1996, 2001, 

2005, 2008, and 2014 and synthesized 

by Barlow (2016); these surveys were 

conducted from the coastline up to ∼556 

km from shore from June or August to 

November or December. These data 

were used by the SWFSC to develop 

spatial models of cetacean densities for 

the California Current Ecosystem (CCE). 

Systematic, offshore, at-sea survey data 

for pinnipeds are more limited (e.g., 

Bonnell et al., 1992; Adams et al., 2014). 

In British Columbia, several systematic 

surveys have been conducted in coastal 

waters (e.g., Williams and Thomas 2007; 

Ford et al., 2010a; Best et al., 2015; 

Harvey et al., 2017). Surveys in coastal 

as well as offshore waters were 

conducted by DFO during 2002 to 2008; 

however, little effort occurred off the 

west coast of Vancouver Island during 

late spring/summer (Ford et al., 2010). 

Density estimates for the survey areas 

outside the U.S. EEZ, i.e., in the 

Canadian EEZ, were not readily 

available, so density estimates for U.S. 

waters were applied to the entire survey 

area. 

The U.S. Navy primarily used SWFSC 

habitat-based cetacean density models 

to develop a marine species density 

database (MSDD) for the Northwest 

Training and Testing (NWTT) Study 

Area for NWTT Phase III activities (U.S. 

Navy 2019a), which encompasses the 

U.S. portion of the survey area. For 

several cetacean species, the Navy 

updated densities estimated by linetransect surveys or mark-recapture 

studies (e.g., Barlow 2016). These 

methods usually produce a single value 

for density that is an averaged estimate 

across very large geographical areas, 

such as waters within the U.S. EEZ off 

California, Oregon, and Washington 

(referred to as a ‘‘uniform’’ density 

estimate). This is the general approach 

applied in estimating cetacean 

abundance in the NMFS stock 

assessment reports. The disadvantage of 

these methods is that they do not 

provide spatially- or temporally-explicit 

density information. More recently, a 

newer method called spatial habitat 

modeling has been used to estimate 

cetacean densities that address some of 

these shortcomings (e.g., Barlow et al., 

2009; Becker et al., 2010; 2012a; 2014; 

Becker et al., 2016; Ferguson et al., 

2006; Forney et al., 2012; 2015; Redfern 

et al., 2006). (Note that spatial habitat 

models are also referred to as ‘‘species 

distribution models’’ or ‘‘habitat-based 

density models.’’) These models 

estimate density as a continuous 

function of habitat variables (e.g., sea 

surface temperature, seafloor depth) and 

thus, within the study area that was 

modeled, densities can be predicted at 

all locations where these habitat 

variables can be measured or estimated. 

Spatial habitat models therefore allow 

estimates of cetacean densities on finer 

scales (spatially and temporally) than 

traditional line-transect or markrecapture analyses. 

The methods used to estimate 

pinniped at-sea densities are typically 

different than those used for cetaceans, 

because pinnipeds are not limited to the 

water and spend a significant amount of 

time on land (e.g., at rookeries). 

Pinniped abundance is generally 

estimated via shore counts of animals 

on land at known haulout sites or by 

counting number of pups weaned at 

rookeries and applying a correction 

factor to estimate the abundance of the 

population (for example Harvey et al., 

1990; Jeffries et al., 2003; Lowry, 2002; 

Sepulveda et al., 2009). Estimating inwater densities from land-based counts 

is difficult given the variability in 

foraging ranges, migration, and haulout 

behavior between species and within 

each species, and is driven by factors 

such as age class, sex class, breeding 

cycles, and seasonal variation. Data 

such as age class, sex class, and seasonal 

variation are often used in conjunction 

with abundance estimates from known 

haulout sites to assign an in-water 

abundance estimate for a given area. 

The total abundance divided by the area 

of the region provides a representative 

in-water density estimate for each 

species in a different location. In 

addition to using shore counts to 

estimate pinniped density, traditional 

line-transect derived estimates are also 

used, particularly in open ocean areas. 

The Navy’s MSDD is currently the 

most comprehensive compendium for 

density data available for the CCE. 

However, data products are currently 

not publically available for the database; 

thus, in this analysis the Navy’s data 

products were used only for species for 

which density data were not available 

from an alternative spatially-explicit 

model (e.g., pinnipeds, Kogia spp., 

minke whales, sei whales, gray whales, 

short-finned pilot whales, and Northern 

Resident, transient, and offshore killer 

whales). For these species, a geographic 

information system (GIS) was used to 

determine the areas expected to be 

ensonified in each density category (i.e., 

distance from shore). For pinnipeds, the 

densities from the Navy’s MSDD were 

corrected by projecting the most recent 

population growth and updated 

population estimates to 2020, when 

available. Where available, the 

appropriate seasonal density estimate 

from the MSDD was used in the 

estimation here (i.e., summer). 

NMFS obtained data products from 

the Navy for densities of Southern 

Resident killer whales in the NWTT 

Offshore Study Area. The modeled 

density estimates were available on the 

scale of 1 km by 1 km grid cells. The 

densities from grid cells overlapping the 

ensonified area in each depth category 

were multiplied by the corresponding 

area to estimate potential exposures 

(Table 9). 

For most other species, (i.e., 

humpback, blue, fin, sperm, Baird’s 

beaked, and other small beaked whales; 

bottlenose, striped, common, Pacific 

white-sided, Risso’s and northern right 

whale dolphins; and Dall’s porpoise), 

habitat-based density models from 

Becker et al. (2016) were used. Becker 

et al. (2016) used seven years of SWFSC 

cetacean line-transect survey data 

collected between 1991 and 2009 to 

develop predictive habitat-based models 

of cetacean densities in the CCE. The 

modeled density estimates were 

available on the scale of 7 km by 10 km 

grid cells. The densities from all grid 

cells overlapping the ensonified areas 

within each water depth category were 

averaged to calculate a zone-specific 

density for each species. 

Becker et al. (2016) did not develop a 

density model for the harbor porpoise, 

so densities from Forney et al. (2014) 

were used for that species. Forney et al. 

(2014) presented estimates of harbor 

porpoise abundance and density along 

the Pacific coast of California, Oregon, 

and Washington based on aerial linetransect surveys conducted between 

2007 and 2012. Separate density 

estimates were provided for harbor 

porpoises in Oregon south of 45° N and 

Oregon/Washington north of 45° N (i.e., 

within the boundaries of the Northern 

California/Southern Oregon and 

Northern Oregon/Washington Coast 

stocks), so stock-specific take estimates 

were generated (Forney et al., 2014). 

Background information on the 

density calculations for each species/ 

guild (if different from the general 

methods from the Navy’s MSDD, Becker 

et al. (2016), or Forney et al. (2014) 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29115 

described above) are reported here. 

Density estimates for each species/guild 

(aside from Southern Resident killer 

whales, which are discussed separately) 

are found in Table 7. 

Gray Whale 

DeAngelis et al. (2011) developed a 

migration model that provides monthly, 

spatially explicit predictions of gray 

whale abundance along the U.S. West 

Coast from December through June. 

These monthly density estimates apply 

to a ‘‘main migration corridor’’ that 

extends from the coast to 10 km 

offshore. A zone from the main 

migration corridor out to 47 km offshore 

is designated as an area of ‘‘potential 

presence’’. To derive a density estimate 

for this area the Navy assumed that 1 

percent of the population could be 

within the 47-km ‘‘potential presence’’ 

area during migration. Given the 2014 

stock assessment population estimate of 

20,990 animals (Carretta et al., 2017b), 

approximately 210 gray whales may use 

this corridor. Assuming the migration 

wave lasts 30 days, then 7 whales on 

average on any one day could occur in 

the ‘‘potential presence’’ area. The area 

from the main migration route offshore 

to 47 km within the NWTT study area 

= 45,722.06 km2, so density within this 

zone = 0.00015 whales/km2. From July– 

November, gray whale occurrence off 

the coast is expected to consist 

primarily of whales belonging to the 

Pacific Coast Feeding Group (PCFG). 

Calambokidis et al. (2012) provided an 

updated analysis of the abundance of 

the PCFG whales in the Pacific 

Northwest and recognized that this 

group forms a distinct feeding 

aggregation. For the purposes of 

establishing density, the Navy assumed 

that from July 1 to November 30 all the 

209 PCFG whales could be present off 

the coast in the Northern California/ 

Oregon/Washington region (this 

accounts for the potential that some 

PCFG whales may be outside of the area 

but that there also may be some nonPCFG whales in the region as noted by 

Calambokidis et al.(2012)). Given that 

the PCFG whales are found largely 

nearshore, it was assumed that all the 

whales could be within 10 km of the 

coast. To capture the potential presence 

of whales further offshore (e.g., Oleson 

et al., 2009), it was assumed that a 

percentage of the whales could be 

present from 10 km out to 47 km off the 

coast; the 47 km outer limit is consistent 

with the DeAngelis et al. (2011) 

migration model. Since 77 percent of 

the PCFG sightings were within the 

nearshore BIAs (Calambokidis et al., 

2015), it was assumed that 23 percent 

(48 whales) could potentially be found 

further offshore. Two strata were thus 

developed for the July–November gray 

whale density layers: (1) From the coast 

to 10 km offshore, and (2) from 10 km 

to 47 km offshore. The density was 

assumed to be 0 animals/km2 for areas 

offshore of 47 km. 

Small Beaked Whale Guild 

NMFS has developed habitat-based 

density models for a small beaked whale 

guild in the CCE (Becker et al., 2012b; 

Forney et al., 2012). The small beaked 

whale guild includes Cuvier’s beaked 

whale and beaked whales of the genus 

Mesoplodon, including Blainville’s 

beaked whale, Hubbs’ beaked whale, 

and Stejneger’s beaked whale. NMFS 

SWFSC developed a CCE habitat-based 

density model for the small beaked 

whale guild which provides spatially 

explicit density estimates off the U.S. 

West Coast for summer and fall based 

on survey data collected between 1991 

and 2009 (Becker et al., 2016). 

False Killer Whale 

False killer whales were not included 

in the Navy’s MSDD, as they are very 

rarely encountered in the northeast 

Pacific. Density estimates for false killer 

whales were also not presented in 

Barlow (2016) or Becker et al. (2016), as 

no sightings occurred during surveys 

conducted between 1986 and 2008 

(Ferguson and Barlow 2001, 2003; 

Forney 2007; Barlow 2003, 2010). One 

sighting was made off of southern 

California during 2014 (Barlow 2016). 

One pod of false killer whales occurred 

in Puget Sound for several months 

during the 1990s (Navy 2015). Based on 

the available information, NMFS does 

not believe false killer whales are 

expected to be taken, but L–DEO has 

requested take of this species so we are 

acting on that request. 

Killer Whale 

A combination of movement data 

(from both visual observations and 

satellite-linked tags) and detections 

from stationary acoustic recorders have 

provided information on the offshore 

distribution of the Southern Resident 

stock (Hanson et al., 2018). These data 

have been used to develop state space 

movement models that provide 

estimates of the probability of 

occurrence (or relative density) of 

Southern Residents in the offshore 

study area in winter and spring (Hanson 

et al., 2018). Since the total number of 

animals that comprise each pod is 

known, the relative density estimates 

were used in association with the total 

abundance estimates to derive absolute 

density estimates (i.e., number of 

animals/km2) within the offshore study 

area. Given that the K and L pods were 

together during all but one of the 

satellite tag deployments, Hanson et al. 

(2018) developed two separate state 

space models, one for the combined K 

and L pods and one for the J pod. The 

absolute density estimates were thus 

derived based on a total of 53 animals 

for the K and L pods (K pod = 18 

animals, L pod = 35 animals) and 22 

animals for the J pod (Center for Whale 

Research, 2019). Of the three pods, the 

K and L pods appear to have a more 

extensive and seasonally variable 

offshore coastal distribution, with rare 

sightings as far south as Monterey Bay, 

California (Carretta et al., 2019; Ford et 

al., 2000; Hanson et al., 2018). Two 

seasonal density maps were thus 

developed for the K and L pods, one 

representing their distribution from 

January to May (the duration of the tag 

deployments), and another representing 

their distribution from June to 

December. Based on stationary acoustic 

recording data, their excursions offshore 

from June to December are more limited 

and typically do not extend south of the 

Columbia River (Emmons 2019). To 

provide more conservative density 

estimates, the Navy extended the June to 

December distribution to just south of 

the Columbia River and redistributed 

the total K and L populations (53 

animals) within the more limited range 

boundaries. A conservative approach 

was also adopted for the J pod since the 

January to May density estimates were 

assumed to represent annual occurrence 

patterns, despite information that this 

pod typically spends more time in the 

inland waters during the summer and 

fall (Carretta et al., 2019; Ford et al., 

2000; Hanson et al., 2018). Further, for 

all seasons the Navy assumed that all 

members of the three pods of Southern 

Residents could occur either offshore or 

in the inland waters, so the total number 

of animals in the stock was used to 

derive density estimates for both study 

areas. 

Due to the difficulties associated with 

reliably distinguishing the different 

stocks of killer whales from at sea 

sightings, and anticipated equal 

likelihood of occurrence among the 

stocks, density estimates for the rest of 

the stocks are presented as a whole (i.e., 

includes the Offshore, West Coast 

Transient, and Northern Resident 

stocks). Barlow (2016) presents density 

values for killer whales in the CCE, with 

separate densities for waters off Oregon/ 

Washington (i.e., north of the California 

border) and Northern California for 

summer/fall. Density data are not 

available for the NWTT Offshore area 

northwest of the CCE study area, so data 

29116 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

from the SWFSC Oregon/Washington 

area were used as representative 

estimates. These values were used to 

represent density year-round. 

Short-Finned Pilot Whale 

Along the U.S. West Coast, shortfinned pilot whales were once common 

south of Point Conception, California 

(Carretta et al., 2017b; Reilly & Shane, 

1986), but now sightings off the U.S. 

West Coast are infrequent and typically 

occur during warm water years (Carretta 

et al., 2017b). Stranding records for this 

species from Oregon and Washington 

waters are considered to be beyond the 

normal range of this species rather than 

an extension of its range (Norman et al., 

2004). Density values for short-finned 

pilot whales are available for the 

SWFSC Oregon/Washington and 

Northern California strata for summer/ 

fall (Barlow, 2016). Density data are not 

available for the NWTT Offshore area 

northwest of the SWFSC strata, so data 

from the SWFSC Oregon/Washington 

stratum were used as representative 

estimates. These values were used to 

represent density year-round. 

Guadalupe Fur Seal 

Adult male Guadalupe fur seals are 

expected to be ashore at breeding areas 

over the summer, and are not expected 

to be present during the planned 

geophysical survey (Caretta et al., 

2017b; Norris 2017b). Additionally, 

breeding females are unlikely to be 

present within the Offshore Study Area 

as they remain ashore to nurse their 

pups through the fall and winter, 

making only short foraging trips from 

rookeries (Gallo-Reynoso et al., 2008; 

Norris 2017b; Yochem et al., 1987). To 

estimate the total abundance of 

Guadalupe fur seals, the Navy adjusted 

the population reported in the 2016 

SAR (Caretta et al., 2017b) of 20,000 

seals by applying the average annual 

growth rate of 7.64 percent over the 

seven years between 2010 and 2017. 

The resulting 2017 projected abundance 

was 33,485 fur seals. Using the reported 

composition of the breeding population 

of Guadalupe fur seals (Gallo-Reynoso 

1994) and satellite telemetry data 

(Norris 2017b), the Navy established 

seasonal and demographic abundances 

of Guadalupe fur seals expected to occur 

within the Offshore Study Area. 

The distribution of Guadalupe fur 

seals in the Offshore Study Area was 

stratified by distance from shore (or 

water depth) to reflect their preferred 

pelagic habitat (Norris, 2017a). Ten 

percent of fur seals in the Study Area 

are expected to use waters over the 

continental shelf (approximated as 

waters with depths between 10 and 200 

m). A depth of 10 m is used as the 

shoreward extent of the shelf (rather 

than extending to shore), because 

Guadalupe fur seals in the Offshore 

Study Area are not expected to haul out 

and would not be likely to come close 

to shore. All fur seals (i.e., 100 percent) 

would use waters off the shelf (beyond 

the 200-m isobath) out to 300 km from 

shore, and 25 of percent of fur seals 

would be expected to use waters 

between 300 and 700 km from shore 

(including the planned geophysical 

survey area). The second stratum (200 m 

to 300 km from shore) is the preferred 

habitat where Guadalupe fur seals are 

most likely to occur most of the time. 

Individuals may spend a portion of their 

time over the continental shelf or farther 

than 300 km from shore, necessitating a 

density estimate for those areas, but all 

Guadalupe fur seals would be expected 

to be in the central stratum most of the 

time, which is the reason 100 percent is 

used in the density estimate for the 

central stratum (Norris, 2017a). Spatial 

areas for the three strata were estimated 

in a GIS and used to calculate the 

densities. 

The Navy’s density estimate for 

Guadalupe fur seals projected the 

abundance through 2017, while L– 

DEO’s survey was initially planned to 

occur in 2020. Therefore, we have 

projected the abundance estimate in 

2020 using the abundance estimate 

(34,187 animals) and population growth 

rate (5.9 percent) presented in the 2019 

draft SARs (Caretta et al., 2019). This 

calculation yielded an increased density 

estimate of Guadalupe fur seals than 

what was presented in the Navy’s 

MSDD. 

Northern Fur Seal 

The Navy estimated the abundance of 

northern fur seals from the Eastern 

Pacific stock and the California breeding 

stock that could occur in the NWTT 

Offshore Study Area by determining the 

percentage of time tagged animals spent 

within the Study Area and applying that 

percentage to the population to 

calculate an abundance for adult 

females, juveniles, and pups 

independently on a monthly basis. 

Adult males are not expected to occur 

within the Offshore Study Area and the 

planned survey area during the planned 

geophysical survey as they spend the 

summer ashore at breeding areas in the 

Bering Sea and San Miguel Island 

(Caretta et al., 2017b). Using the 

monthly abundances of fur seals within 

the Offshore Study Area, the Navy 

created strata to estimate the density of 

fur seals within three strata: 22 km to 70 

km from shore, 70 km to 130 km from 

shore, and 130 km to 463 km from shore 

(the western Study Area boundary). L– 

DEO’s planned survey is 423 km from 

shore at the closest point. Based on 

satellite tag data and historic sealing 

records (Olesiuk 2012; Kajimura 1984), 

the Navy assumed 25 percent of the 

population present within the overall 

Offshore Study Area may be within the 

130 km to 463 km stratum. 

The Navy’s density estimates for 

northern fur seals did not include the 

latest abundance data collected from 

Bogoslof Island or the Pribilof Islands in 

2015 and 2016. Incorporating the latest 

pup counts yielded a slight decrease in 

the population abundance estimate, 

which resulted in a slight decrease in 

the estimated densities of northern fur 

seals in each depth stratum. 

Steller Sea Lion 

The Eastern stock of Steller sea lions 

has established rookeries and breeding 

sites along the coasts of California, 

Oregon, British Columbia, and southeast 

Alaska. A new rookery was recently 

discovered along the coast of 

Washington at the Carroll Island and 

Sea Lion Rock complete, where more 

than 100 pups were born in 2015 (Muto 

et al., 2017; Wiles 2015). The 2017 SAR 

did not factor in pups born at sites along 

the Washington coast (Muto et al., 

2017). Considering that pups have been 

observed at multiple breeding sites 

since 2013, specifically at the Carroll 

Island and Sea Lion Rock complex 

(Wiles 2015), the 2017 SAR abundance 

of 1,407 Steller sea lions (non-pups 

only) for Washington underestimates 

the total population. Wiles (2015) 

estimates that up to 2,500 Steller sea 

lions are present along the Washington 

coast, which is the abundance estimate 

used by the Navy to calculate densities. 

Approximately 30,000 Steller sea lions 

occur along the coast of British 

Columbia, but these animals were not 

included in the Navy’s calculations. The 

Navy applied the annual growth rate for 

each regional population (California, 

Oregon, Washington, and southeast 

Alaska), reported in Muto et al. (2017), 

to each population to estimate the stock 

abundance in 2017, and we further 

projected the population estimate in 

2020. The Commission noted that we 

had used the non-pup population 

growth rate to project the population of 

both non-pups and pups. Additionally, 

the Commission suggested we include 

the British Columbia population in our 

projections. We have revised the 

population projections and resulting 

density estimates accordingly. 

Sea lions from northern California 

and southern Oregon rookeries migrate 

north in September following the 

breeding season and winter in northern 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29117 

Oregon, Washington, and British 

Columbia waters. They disperse widely 

following the breeding season, which 

extends from May through July, likely in 

search of different types of prey, which 

may be concentrated in areas where 

oceanic fronts and eddies persist (Fritz 

et al., 2016; Jemison et al., 2013; Lander 

et al., 2010; Muto et al., 2017; NMFS 

2013; Raum-Suryan et al., 2004; Sigler 

et al., 2017). Adults depart rookeries in 

August. Females with pups remain 

within 500 km of their rookery during 

the non-breeding season and juveniles 

of both sexes and adult males disperse 

more widely but remain primarily over 

the continental shelf (Wiles 2015). 

Based on 11 sightings along the 

Washington coast, Steller sea lions were 

observed at an average distance of 13 

km from shore and 35 km from the shelf 

break (defined as the 200-m isobath) 

(Oleson et al., 2009). The mean water 

depth in the area of occurrence was 42 

m, and surveys were conducted out to 

approximately 60 km from shore. Wiles 

(2015) estimated that Steller sea lions 

off the Washington coast primarily 

occurred within 60 km of shore, 

favoring habitats over the continental 

shelf. However, a few individuals may 

travel several hundred km offshore 

(Merrick & Loughlin 1997; Wiles 2015). 

Based on these occurrence and 

distribution data, two strata were used 

to estimate densities for Steller sea 

lions. The spatial area extending from 

shore to the 200-m isobath (i.e., over the 

continental shelf) was defined as one 

stratum, and the second stratum 

extended from the 200-m isobath to 300 

km from shore to account for reports of 

Steller sea lions occurring several 

hundred km offshore. Ninety-five 

percent of the population of Steller sea 

lions occurring in the NWTT Study 

Area were distributed over the 

continental shelf stratum and the 

remaining five percent were assumed to 

occur between the 200-m isobath and 

300 km from shore. 

The percentage of time Steller sea 

lions spend hauled out varies by season, 

life stage, and geographic location. To 

calculated densities in the Study Area, 

the projected population abundance was 

adjusted to account for time spent 

hauled out. In spring and winter, sea 

lions were estimated to be in the water 

64 percent of the time. In summer, when 

sea lions are more likely to be in the 

water, the percent of animals estimated 

to be in the water was increased to 76 

percent, and in fall, sea lions were 

anticipated to be in the water 53 percent 

of the time (U.S. Navy 2019). Densities 

were calculated for each depth stratum 

off Washington and off Oregon. 

California Sea Lion 

Seasonal at-sea abundance of 

California sea lions is estimated from 

strip transect survey data collected 

offshore along the California coastline 

(Lowry & Forney 2005). The survey area 

was divided into seven strata, labeled A 

through G. Abundance estimates from 

the two northernmost strata (A and B) 

were used to estimate the abundance of 

California sea lions occurring in the 

NWTT Study Area. While the 

northernmost stratum (A) only partially 

overlaps with the Study Area, this 

approach conservatively assumes that 

all sea lions from the two strata would 

continue north into the Study Area. 

The majority of male sea lions would 

be expected in the NWTT Study Area 

from August to mid-June (Wright et al., 

2010). In summer, males are expected to 

be at breeding sites off of Southern 

California. In-water abundance 

estimates of adult and sub-adult males 

in strata A and B were extrapolated to 

estimate seasonal densities in the Study 

Area. Approximately 3,000 male 

California sea lions are known to pass 

through the NWTT Study Area in 

August as they migrate northward to the 

Washington coast and inland waters 

(DeLong 2018a; Wright et al., 2010). 

Nearly all male sea lions are expected to 

be on or near breeding sites off 

California in July (DeLong et al., 2017; 

Wright et al., 2010). An estimate of 

3,000 male sea lions is used for the 

month of August. Projected 2017 

seasonal abundance estimates were 

derived by applying an annual growth 

rate of 5.4 percent (Caretta et al., 2017b) 

between 1999 and 2017 to the 

abundance estimates from Lowry & 

Forney (2005). 

The strata used to calculated densities 

in the NWTT Study Area were based on 

distribution data from Wright et al. 

(2010) and Lowry & Forney (2005) 

indicating that approximately 90 

percent of California sea lions occurred 

within 40 km of shore and 100 percent 

of sea lions were within 70 km of shore. 

A third stratum was added that extends 

from shore to 450 km offshore to 

account for anomalous conditions, such 

as changes in sea surface temperature 

and upwelling associated with El Nin ̃ o, 

during which California sea lions have 

been encountered farther from shore, 

presumably seeking prey (DeLong & 

Jeffries 2017; Weise et al., 2010). The 

Navy calculated densities for each 

stratum (0 to 40 km, 40 to 70 km, and 

0 to 450 km) for each season, spring, 

summer, fall, and winter, but noted that 

the density of California sea lions in all 

strata for June and July was 0 animals/ 

km2. The Navy’s calculated densities for 

August were conservatively used here, 

as sightings of California sea lions have 

been reported on the continental shelf 

in June and July (Adams et al., 2014). 

Northern Elephant Seal 

The most recent surveys supporting 

the abundance estimate for northern 

elephant seals were conducted in 2010 

(Caretta et al., 2017b). By applying the 

average growth rate of 3.8 percent per 

year for the California breeding stock 

over the 7 years from 2010 to 2017, the 

Navy calculated a projected 2017 

abundance estimate of 232,399 elephant 

seals (Caretta et al., 2017b; Lowry et al., 

2014). Male and female distributions at 

sea differ both seasonally and spatially. 

Pup counts reported by Lowry et al., 

(2014) and life tables compiled by 

Condit et al., (2014) were used to 

determine the proportion of males and 

females in the population, which was 

estimated to be 56 percent female and 

44 percent male. Females are assumed 

to be at sea 100 percent of the time 

within their seasonal distribution area 

in fall and summer (Robinson et al., 

2012). Males are at sea approximately 90 

percent of the time in fall and spring, 

remain ashore through the entire winter, 

and spend one month ashore to molt in 

the summer (i.e., are at sea 66 percent 

of the summer). Monthly distribution 

maps produced by Robinson et al. 

(2012) showing the extent of foraging 

areas used by satellite tagged female 

elephant seals were used to estimate the 

spatial areas to calculate densities. 

Although the distributions were based 

on tagged female seals, Le Boeuf et al. 

(2000) and Simmons et al. (2007) 

reported similar tracks by males over 

broad spatial scales. The spatial areas 

representing each monthly distribution 

were calculating using GIS and then 

averaged to produce seasonally variable 

areas and resulting densities. 

As with other pinniped species above, 

NMFS used the population growth rate 

reported by Caretta et al. (2017b) to 

project the estimated abundance in 

2020. The resulting population estimate 

and estimated densities increased from 

those presented in the Navy’s MSDD 

(U.S. Navy 2019). 

Harbor Seal 

Only harbor seals from the 

Washington and Oregon Coast stock 

would be expected to occur in the 

survey area. The most recent abundance 

estimate for the Washington and Oregon 

Coast stock is 24,732 harbor seals 

(Caretta et al., 2017b). Survey data 

supporting this abundance estimate are 

from 1999, which exceeds the 8 year 

limit beyond which NMFS will not 

confirm abundance in a SAR (Caretta et 

29118 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

al., 2017b). However, based on logistical 

growth curves for the Washington and 

Oregon Coast stock that leveled off in 

the early 1990s (Caretta et al., 2017b) 

and unpublished data from the 

Washington Department of Fish and 

Wildlife (DeLong & Jeffries 2017), an 

annual growth rate of 0 percent (i.e., the 

population has remained stable) was 

applied such that the 2017 abundance 

estimate used by the Navy, and 2020 

estimate used here, was still 24,732 

harbor seals. A haulout factor of 33 

percent was used to account for hauledout seals (i.e., seals are estimated to be 

in the water 33 percent of the time) 

(Huber et al., 2001). A single stratum 

extending from shore to 30 km offshore 

was used to define the spatial area used 

by the Navy for calculating densities off 

Washington and Oregon (Bailey et al., 

2014; Oleson et al., 2009). 

No significant new information is 

available since we published the notice 

of proposed IHA, and no changes have 

been made, other than those described 

in the Changes from the Proposed IHA 

section, provided previously in this 

document. 

Marine Mammal Densities 

Densities for most species are 

presented by depth stratum (shallow, 

intermediate, and deep water) in Table 

7. For species where densities are 

available based on other categories (gray 

whale, harbor porpoise, northern fur 

seal, Guadalupe fur seal, California sea 

lion, Steller sea lion), category 

definitions are provided in the footnotes 

of Table 7. 

TABLE 7—MARINE MAMMAL DENSITY VALUES IN THE SURVEY AREA

Species 

Estimated density (#/km2) 

Reference Shallow <100 

m/Category 1 

Intermediate 

100–1,000 

m/Category 2 

Deep >1,000 

m/Category 3 

LF Cetaceans: 

Humpback whale ..................................... 0.0052405 0.0040200 0.0004830 Becker et al. (2016) 

Blue whale ............................................... 0.0020235 0.0010518 0.0003576 Becker et al. (2016) 

Fin whale ................................................. 0.0002016 0.0009306 0.0013810 Becker et al. (2016) 

Sei whale ................................................. 0.0004000 0.0004000 0.0004000 U.S. Navy (2019) 

Minke whale ............................................. 0.0013000 0.0013000 0.0013000 U.S. Navy (2019) 

Gray whale a ............................................ 0.0155000 0.0010000 N.A. U.S. Navy (2019) 

MF Cetaceans: 

Sperm whale ............................................ 0.0000586 0.0001560 0.0013023 Becker et al. (2016) 

Baird’s beaked whale .............................. 0.0001142 0.0002998 0.0014680 Becker et al. (2016) 

Small beaked whale ................................ 0.0007878 0.0013562 0.0039516 Becker et al. (2016) 

Bottlenose dolphin ................................... 0.0000007 0.0000011 0.0000108 Becker et al. (2016) 

Striped dolphin ......................................... 0.0000000 0.0000025 0.0001332 Becker et al. (2016) 

Short-beaked common dolphin ................ 0.0005075 0.0010287 0.0016437 Becker et al. (2016) 

Pacific white-sided dolphin ...................... 0.0515230 0.0948355 0.0700595 Becker et al. (2016) 

Northern right-whale dolphin ................... 0.0101779 0.0435350 0.0621242 Becker et al. (2016) 

Risso’s dolphin ......................................... 0.0306137 0.0308426 0.0158850 Becker et al. (2016) 

False killer whale b ................................... N.A. N.A. N.A. 

Killer whale (all stocks except Southern 

Residents).

0.0009200 0.0009200 0.0009200 U.S. Navy (2019) 

Short-finned pilot whale ........................... 0.0002500 0.0002500 0.0002500 U.S. Navy (2019) 

HF Cetaceans: 

Pygmy/dwarf sperm whale ...................... 0.0016300 0.0016300 0.0016300 U.S. Navy (2019) 

Dall’s porpoise ......................................... 0.1450767 0.1610605 0.1131827 Becker et al. (2016) 

Harbor porpoise c ..................................... 0.6240000 0.4670000 N.A. Forney et al. (2014) 

Otariids: 

Northern fur seal d .................................... 0.0113247 0.1346441 0.0103424 U.S. Navy (2019) 

Guadalupe fur seal e ................................ 0.0234772 0.0262595 N.A. U.S. Navy (2019) 

California sea lion f ................................... 0.0288000 0.0037000 0.0065000 U.S. Navy (2019) 

Steller sea lion g ....................................... 0.4804893 0.0035811 N.A. U.S. Navy (2019) 

Phocids: 

Northern elephant seal ............................ 0.0345997 0.0345997 0.0345997 U.S. Navy (2019) 

Harbor seal h ............................................ 0.3424000 N.A. N.A. U.S. Navy (2019) 

a Category 1 = 0–10 km offshore, Category 2 = 10–47 km offshore (U.S. Navy 2019). 

b No density estimates available for false killer whales in the survey area, take is based on mean group size from Mobley et al. (2000). c Category 1 = South of 45° N, Category 2 = North of 45° N (Forney et al., 2014). d Category 1 = 22–70 km offshore, Category 2 = 70–130 km offshore, Category 3 = 130–463 km offshore (U.S. Navy 2019). 

e Category 1 = 10–200 m depth, Category 2 = 200 m depth–300 km offshore; No stock-specific densities are available so these densities were 

applied to northern fur seals as a species (U.S. Navy 2019). f Category 1 = 0–40 km offshore, Category 2 = 40–70 km offshore, Category 3 = 0–450 km offshore (U.S. Navy 2019). 

g Category 1 = shore–200 m depth, Category 2 = 200 m depth–300 m offshore (U.S. Navy 2019). 

h Category 1 = 0–30 km offshore (U.S. Navy 2019). 

Take Calculation and Estimation 

Here we describe how the information 

provided above is brought together to 

produce a quantitative take estimate. In 

order to estimate the number of marine 

mammals predicted to be exposed to 

sound levels that would result in Level 

A or Level B harassment, radial 

distances from the airgun array to 

predicted isopleths corresponding to the 

Level A harassment and Level B 

harassment thresholds are calculated, as 

described above. Those radial distances 

are then used to calculate the area(s) 

around the airgun array predicted to be 

ensonified to sound levels that exceed 

the Level A and Level B harassment 

thresholds. The distance for the 160-dB 

threshold (based on L–DEO model 

results) was used to draw a buffer 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29119 

around every transect line in GIS to 

determine the total ensonified area in 

each depth category (Table 8). The areas 

presented in Table 8 do not include 

areas ensonified within Canadian 

territorial waters (from 0–12 nmi (22.2 

km) from shore). As discussed above, 

NMFS cannot authorize the incidental 

take of marine mammals in the 

territorial seas of foreign nations, as the 

MMPA does not apply in those waters. 

However, NMFS has still calculated the 

level of incidental take in the entire 

activity area (including Canadian 

territorial waters) as part of the analysis 

supporting our determination under the 

MMPA that the activity will have a 

negligible impact on the affected 

species. The total estimated take in U.S. 

and Canadian waters is presented in 

Table 11. 

In past applications, to account for 

unanticipated delays in operations, 

L–DEO has added 25 percent in the 

form of operational days, which is 

equivalent to adding 25 percent to the 

proposed line km to be surveyed. In this 

application, however, due to the strict 

operational timelines and availability of 

the R/V Langseth, no additional time or 

distance has been added to the survey 

calculations. 37 days is the absolute 

maximum amount of time the R/V 

Langseth is available to conduct seismic 

operations. 

The ensonified areas in Table 8 were 

used to estimate take of marine mammal 

species with densities available for the 

three depth strata (shallow, 

intermediate, and deep waters). For 

other species where densities are 

available based on other categories (i.e., 

gray whale, harbor porpoise, northern 

fur seal, Guadalupe fur seal, California 

sea lion, Steller sea lion; see Table 7), 

GIS was used to determine the areas 

expected to be ensonified in each 

density category (see L–DEO’s EA for 

the ensonified areas in each category). 

The areas provided in Tables 8 and 9 

here have been updated from those 

provided in Tables 8 and 9 of the notice 

of proposed IHA (85 FR 19580; April 7, 

2020) based on the revised planned 

survey tracklines. 

TABLE 8—AREAS (KM2) ESTIMATED TO BE ENSONIFIED TO LEVEL A AND LEVEL B HARASSMENT THRESHOLDS

Survey zone Criteria 

Relevant 

isopleth 

(m) 

Total 

ensonified 

area 

(km2) 

Level B Harassment: 

Shallow <100 m ..................................................... 160 dB .......................................................................... a 12,650 3,580.73 

Intermediate 100–1,000 m .................................... 160 dB .......................................................................... b 9,468 23,562.43 

Deep >1,000 m ..................................................... 160 dB .......................................................................... b 6,733 52,438.71 

Overall ............................................................ ....................................................................................... ........................ 79,581.85 

Level A Harassment: 

All depth zones ...................................................... LF Cetacean ................................................................. 426.9 5,334.55 

MF Cetacean ................................................................ 13.6 171.42 

HF Cetacean ................................................................ 268.3 3,363.99 

Otariid ........................................................................... 10.6 133.61 

Phocid ........................................................................... 43.7 550.53 

aBased on L–DEO model results 

bBased on data from Crone et al. (2014) 

Density estimates for Southern 

Resident killer whales from the U.S. 

Navy’s MSDD were overlaid with GIS 

layers of the Level B harassment zones 

in each depth category to determine the 

areas expected to be ensonified in each 

density category (Table 9). 

TABLE 9—SOUTHERN RESIDENT KILLER WHALE DENSITIES AND CORRESPONDING ENSONIFIED AREAS

Pod Density (animals/km2) Ensonified area 

(km2) 

K/L ............................................................................................................................................................... 0.000000 5,888 

0.000001–0.002803 15,470 

0.002804–0.005615 342 

0.005616–0.009366 0 

0.009367–0.015185 0 

J ................................................................................................................................................................... 0.000000 6,427 

0.000001–0.001991 5,556 

0.001992–0.005010 0 

0.005011–0.009602 0 

0.009603–0.018822 20 

The marine mammals predicted to 

occur within these respective areas, 

based on estimated densities or other 

occurrence records, are assumed to be 

incidentally taken. For species where 

NMFS expects take by Level A 

harassment to potentially occur, the 

calculated Level A harassment takes 

have been subtracted from the total 

within the Level B harassment zone. 

Estimated exposures for the survey 

outside of Canadian territorial waters 

are shown in Table 10. These numbers 

have changed from those provided in 

Table 10 of the notice of proposed IHA 

(85 FR 19580; April 7, 2020) because of 

the revised planned survey tracklines. 

29120 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

TABLE 10—ESTIMATED TAKING BY LEVEL A AND LEVEL B HARASSMENT, AND PERCENTAGE OF POPULATION

Species MMPA stock a Stock 

abundance 

Estimated take Total 

authorized 

take 

Percent of 

MMPA stock Level 1B Level 1A 

LF Cetaceans: 

Central North Pacific .......... 10,103 112 29 b 141 1.40 

Humpback whale ......... California/Oregon/Washington.2,900 ........................ ........................ ........................ 4.86 

Blue whale ................... Eastern North Pacific ......... 1,647 40 11 51 3.10 

Fin whale ..................... California/Oregon/Washington.9,029 94 1 95 1.05 

Northeast Pacific ................ 3,168 ........................ ........................ ........................ 3.00 

Sei whale ..................... Eastern North Pacific ......... 27,197 30 2 32 0.12 

Minke whale ................. California/Oregon/Washington.25,000 96 7 103 0.41 

Gray whale ................... Eastern North Pacific ......... 26,960 43 1 44 0.16 

MF Cetaceans: 

Sperm whale ................ California/Oregon/Washington.26,300 72 0 72 0.27 

Baird’s beaked whale .. California/Oregon/Washington.2,697 84 0 84 3.12 

Small beaked whale .... California/Oregon/Washington.6,318 242 0 c 242 3.83 

Bottlenose dolphin ....... California/Oregon/Washington (offshore).1,924 1 0 d 13 0.68 

Striped dolphin ............. California/Oregon/Washington.29,211 7 0 d 46 0.16 

Short-beaked common 

dolphin.

California/Oregon/Washington.969,861 112 0 d 179 0.02 

Pacific white-sided dolphin.California/Oregon/Washington.26,814 6,084 0 6,084 22.69 

Northern right-whale 

dolphin.

California/Oregon/Washington.26,556 4,318 0 4,318 16.26 

Risso’s dolphin ............. California/Oregon/Washington.6,336 1,664 0 1,664 26.26 

False killer whale ......... n/a ...................................... Unknown n/a n/a e 5 f n/a 

Killer whale .................. Southern Resident ............. 73 10 0 10 13.70 

Northern Resident .............. 302 73 0 73 24.17 

West Coast Transient ......... 349 ........................ ........................ ........................ 20.92 

Offshore .............................. 300 ........................ ........................ ........................ 24.33 

Short-finned pilot whale California/Oregon/Washington.836 20 0 d 29 3.47 

HF Cetaceans: 

Pygmy/dwarf sperm 

whale.

California/Oregon/Washington.4,111 125 5 130 3.16 

Dall’s porpoise ............. California/Oregon/Washington.27,750 9,762 488 10,250 g 36.94 

Harbor porpoise ........... Northern Oregon/Washington Coast.21,487 7,958 283 8,241 g 38.35 

Northern California/Southern Oregon.35,769 ........................ ........................ ........................ 23.04 

Otariid Seals: 

Northern fur seal .......... Eastern Pacific ................... 608,143 4,592 0 4,592 0.76 

California ............................ 14,050 ........................ ........................ ........................ 32.68 

Guadalupe fur seal ...... Mexico to California ........... 34,187 2,048 0 2,048 5.99 

California sea lion ........ U.S. .................................... 257,606 889 0 889 0.35 

Steller sea lion ............. Eastern U.S. ....................... 43,201 7,504 0 7,504 17.37 

Phocid Seals: 

Northern elephant seal California Breeding ............. 179,000 2,754 0 2,754 1.54 

Harbor seal .................. Oregon/Washington Coast h 24,732 3,887 0 3,887 15.72 

a In most cases, where multiple stocks are being affected, for the purposes of calculating the percentage of the stock impacted, the take is 

being analyzed as if all authorized takes occurred within each stock. bTakes are allocated among the three DPSs in the area based on Wade et al. (2017) (Oregon: 32.7% Mexico DPS, 67.2% Central America 

DPS; Washington/British Columbia: 27.9% Mexico DPS, 8.7% Central America DPS, 63.5% Hawaii DPS). cTotal for small beaked whale guild (Appendix B of L–DEO’s application describes potential take estimates of each species represented in the 

guild, but we present the authorized take of small beaked whales as a whole). dAuthorized take increased to mean group size from Barlow (2016). 

eAuthorized take increased to mean group size from Mobley et al. (2000). fFalse killer whales that may be taken during this survey are not likely to belong to any designated stock. Therefore we cannot determine the 

percent of stock that may be taken, but we assume that five individuals would be considered small relative to the abundance of the population 

they belong to. gThe percentage of these stocks expected to experience take is discussed further in the Small Numbers section later in the document. hAs noted in Table 1, there is no current estimate of abundance available for the Oregon/Washington Coast stock of harbor seal. The abundance estimate from 1999, included here, is the best available. 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29121 

Marine mammals would be expected 

to move away from a loud sound source 

that represents an aversive stimulus, 

such as an airgun array, potentially 

reducing the number of takes by Level 

A harassment. However, the extent to 

which marine mammals would move 

away from the sound source is difficult 

to quantify and is therefore not 

accounted for in the take estimates. 

Also, note that in consideration of the 

near-field soundscape of the airgun 

array, we have authorized a different 

number of takes of mid-frequency 

cetaceans and pinnipeds by Level A 

harassment than the number estimated 

by L–DEO (see Appendix B in L–DEO’s 

IHA application). 

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 and 

impact on operations. 

L–DEO has reviewed mitigation 

measures employed during seismic 

research surveys authorized by NMFS 

under previous incidental harassment 

authorizations, as well as recommended 

best practices in Richardson et al. 

(1995), Pierson et al. (1998), Weir and 

Dolman (2007), Nowacek et al. (2013), 

Wright (2014), and Wright and 

Cosentino (2015), and incorporated a 

suite of proposed mitigation measures 

into their project description based on 

the above sources. 

To reduce the potential for 

disturbance from acoustic stimuli 

associated with the activities, L–DEO 

will implement mitigation measures for 

marine mammals. Mitigation measures 

that will be adopted during the planned 

surveys include (1) Vessel-based visual 

mitigation monitoring; (2) Vessel-based 

passive acoustic monitoring; (3) 

Establishment of an exclusion zone; (4) 

Shutdown procedures; (5) Ramp-up 

procedures; and (6) Vessel strike 

avoidance measures. 

Vessel-Based Visual Mitigation 

Monitoring 

Visual monitoring requires the use of 

trained observers (herein referred to as 

visual PSOs) to scan the ocean surface 

visually for the presence of marine 

mammals. The area to be scanned 

visually includes primarily the 

exclusion zone, within which 

observation of certain marine mammals 

requires shutdown of the acoustic 

source, but also the buffer zone. The 

buffer zone means an area beyond the 

exclusion zone to be monitored for the 

presence of marine mammals that may 

enter the exclusion zone. During preclearance monitoring (i.e., before rampup begins), the buffer zone also acts as 

an extension of the exclusion zone in 

that observations of marine mammals 

within the buffer zone would also 

prevent airgun operations from 

beginning (i.e., ramp-up). The buffer 

zone encompasses the area at and below 

the sea surface from the edge of the 0– 

500 m exclusion zone, out to a radius 

of 1,000 m from the edges of the airgun 

array (500–1,000 m). Visual monitoring 

of the exclusion zone and adjacent 

waters is intended to establish and, 

when visual conditions allow, maintain 

zones around the sound source that are 

clear of marine mammals, thereby 

reducing or eliminating the potential for 

injury and minimizing the potential for 

more severe behavioral reactions for 

animals occurring closer to the vessel. 

Visual monitoring of the buffer zone is 

intended to (1) provide additional 

protection to naı ̈ve marine mammals 

that may be in the area during preclearance, and (2) during airgun use, aid 

in establishing and maintaining the 

exclusion zone by alerting the visual 

observer and crew of marine mammals 

that are outside of, but may approach 

and enter, the exclusion zone. 

L–DEO must use dedicated, trained, 

NMFS-approved Protected Species 

Observers (PSOs). The PSOs must have 

no tasks other than to conduct 

observational effort, record 

observational data, and communicate 

with and instruct relevant vessel crew 

with regard to the presence of marine 

mammals and mitigation requirements. 

PSO resumes must be provided to 

NMFS for approval. 

At least one of the visual and two of 

the acoustic PSOs (discussed below) 

aboard the vessel must have a minimum 

of 90 days at-sea experience working in 

those roles, respectively, during a deep 

penetration (i.e., ‘‘high energy’’) seismic 

survey, with no more than 18 months 

elapsed since the conclusion of the atsea experience. One visual PSO with 

such experience must be designated as 

the lead for the entire protected species 

observation team. The lead PSO must 

serve as primary point of contact for the 

vessel operator and ensure all PSO 

requirements per the IHA are met. To 

the maximum extent practicable, the 

experienced PSOs should be scheduled 

to be on duty with those PSOs with 

appropriate training but who have not 

yet gained relevant experience. 

During survey operations (e.g., any 

day on which use of the acoustic source 

is planned to occur, and whenever the 

acoustic source is in the water, whether 

activated or not), a minimum of two 

visual PSOs must be on duty and 

conducting visual observations at all 

times during daylight hours (i.e., from 

30 minutes prior to sunrise through 30 

minutes following sunset). Visual 

monitoring of the exclusion and buffer 

zones must begin no less than 30 

minutes prior to ramp-up and must 

continue until one hour after use of the 

acoustic source ceases or until 30 

minutes past sunset. Visual PSOs must 

coordinate to ensure 360° visual 

coverage around the vessel from the 

most appropriate observation posts, and 

must conduct visual observations using 

binoculars and the naked eye while free 

from distractions and in a consistent, 

systematic, and diligent manner. 

PSOs must establish and monitor the 

exclusion and buffer zones. These zones 

must be based upon the radial distance 

from the edges of the acoustic source 

(rather than being based on the center of 

the array or around the vessel itself). 

During use of the acoustic source (i.e., 

anytime airguns are active, including 

29122 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

ramp-up), detections of marine 

mammals within the buffer zone (but 

outside the exclusion zone) must be 

communicated to the operator to 

prepare for the potential shutdown of 

the acoustic source. 

During use of the airgun (i.e., anytime 

the acoustic source is active, including 

ramp-up), detections of marine 

mammals within the buffer zone (but 

outside the exclusion zone) should be 

communicated to the operator to 

prepare for the potential shutdown of 

the acoustic source. Visual PSOs must 

immediately communicate all 

observations to the on duty acoustic 

PSO(s), including any determination by 

the PSO regarding species 

identification, distance, and bearing and 

the degree of confidence in the 

determination. Any observations of 

marine mammals by crew members 

must be relayed to the PSO team. During 

good conditions (e.g., daylight hours; 

Beaufort sea state (BSS) 3 or less), visual 

PSOs must conduct observations when 

the acoustic source is not operating for 

comparison of sighting rates and 

behavior with and without use of the 

acoustic source and between acquisition 

periods, to the maximum extent 

practicable. 

While the R/V Langseth is surveying 

in water depths of 200 m or less along 

the coast between Tillamook Head, 

Oregon and Barkley Sound, British 

Columbia (between latitudes 

45.9460903° N and 48.780291° N), and 

within the boundaries of Olympic Coast 

National Marine Sanctuary, a second 

vessel with additional PSOs must travel 

approximately 5 km ahead of the R/V 

Langseth. Two PSOs must be on watch 

on the second vessel during all such 

survey operations and must alert PSOs 

on the R/V Langseth of any marine 

mammal observations so that they may 

be prepared to initiate shutdowns. This 

requirement has been modified from 

what was included in the proposed IHA, 

which proposed using the second vessel 

through the entire survey area in waters 

under 200 m. This requirement was 

primarily intended to increase the 

likelihood of PSOs detecting Southern 

Resident killer whales. However, L– 

DEO has described practicability 

concerns with the second vessel, 

including high cost and limited 

availability for the time period 

specified. NMFS carefully considered 

the area in which the second vessel 

would effect the most reduction in 

impacts to Southern Resident killer 

whales and, accordingly, the area 

requiring the second vessel has been 

revised to reflect the areas of highest 

occurrence (based on Navy, 2019), 

between Tillamook Head and Barkley 

Sound and within the boundaries of 

Olympic Coast National Marine 

Sanctuary. 

Visual PSOs on both vessels may be 

on watch for a maximum of four 

consecutive hours followed by a break 

of at least one hour between watches 

and may conduct a maximum of 12 

hours of observation per 24-hour period. 

Combined observational duties (visual 

and acoustic but not at same time) may 

not exceed 12 hours per 24-hour period 

for any individual PSO. 

Passive Acoustic Monitoring 

Acoustic monitoring means the use of 

trained personnel (sometimes referred to 

as passive acoustic monitoring (PAM) 

operators, herein referred to as acoustic 

PSOs) to operate PAM equipment to 

acoustically detect the presence of 

marine mammals. Acoustic monitoring 

involves acoustically detecting marine 

mammals regardless of distance from 

the source, as localization of animals 

may not always be possible. Acoustic 

monitoring is intended to further 

support visual monitoring (during 

daylight hours) in maintaining an 

exclusion zone around the sound source 

that is clear of marine mammals. In 

cases where visual monitoring is not 

effective (e.g., due to weather, 

nighttime), acoustic monitoring may be 

used to allow certain activities to occur, 

as further detailed below. 

Passive acoustic monitoring will take 

place in addition to the visual 

monitoring program. Visual monitoring 

typically is not effective during periods 

of poor visibility or at night, and even 

with good visibility, is unable to detect 

marine mammals when they are below 

the surface or beyond visual range. 

Acoustical monitoring can be used in 

addition to visual observations to 

improve detection, identification, and 

localization of cetaceans. The acoustic 

monitoring will serve to alert visual 

PSOs (if on duty) when vocalizing 

cetaceans are detected. It is only useful 

when marine mammals call, but it can 

be effective either by day or by night, 

and does not depend on good visibility. 

It will be monitored in real time so that 

the visual observers can be advised 

when cetaceans are detected. 

The R/V Langseth must use a towed 

PAM system, which must be monitored 

by at a minimum one on duty acoustic 

PSO beginning at least 30 minutes prior 

to ramp-up and at all times during use 

of the acoustic source. Acoustic PSOs 

may be on watch for a maximum of 4 

consecutive hours followed by a break 

of at least 1 hour between watches and 

may conduct a maximum of 12 hours of 

observation per 24-hour period. 

Combined observational duties (acoustic 

and visual but not at same time) may 

not exceed 12 hours per 24-hour period 

for any individual PSO. 

Survey activity may continue for 30 

minutes when the PAM system 

malfunctions or is damaged, while the 

PAM operator diagnoses the issue. If the 

diagnosis indicates that the PAM system 

must be repaired to solve the problem, 

operations may continue for an 

additional five hours without acoustic 

monitoring during daylight hours only 

under the following conditions: 

• Sea state is less than or equal to 

BSS 4; 

• No marine mammals (excluding 

delphinids, other than killer whales) 

detected solely by PAM in the 

applicable exclusion zone in the 

previous 2 hours; 

• NMFS is notified via email as soon 

as practicable with the time and 

location in which operations began 

occurring without an active PAM 

system; and 

• Operations with an active acoustic 

source, but without an operating PAM 

system, do not exceed a cumulative total 

of five hours in any 24-hour period. 

Establishment of Exclusion and Buffer 

Zones 

An exclusion zone (EZ) is a defined 

area within which occurrence of a 

marine mammal triggers mitigation 

action intended to reduce the potential 

for certain outcomes, e.g., auditory 

injury, disruption of critical behaviors. 

The PSOs must establish a minimum EZ 

with a 500-m radius. The 500-m EZ 

must be based on radial distance from 

the edge of the airgun array (rather than 

being based on the center of the array 

or around the vessel itself). With certain 

exceptions (described below), if a 

marine mammal appears within or 

enters this zone, the acoustic source 

must be shut down. 

The 500-m EZ is intended to be 

precautionary in the sense that it would 

be expected to contain sound exceeding 

the injury criteria for all cetacean 

hearing groups, (based on the dual 

criteria of SELcum and peak SPL), while 

also providing a consistent, reasonably 

observable zone within which PSOs 

would typically be able to conduct 

effective observational effort. 

Additionally, a 500-m EZ is expected to 

minimize the likelihood that marine 

mammals will be exposed to levels 

likely to result in more severe 

behavioral responses. Although 

significantly greater distances may be 

observed from an elevated platform 

under good conditions, we believe that 

500 m is likely regularly attainable for 

PSOs using the naked eye during typical 

conditions. 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29123 

An extended EZ of 1,500 m must be 

enforced for all beaked whales, and 

dwarf and pygmy sperm whales. No 

buffer zone is required. 

Pre-Clearance and Ramp-Up 

Ramp-up (sometimes referred to as 

‘‘soft start’’) means the gradual and 

systematic increase of emitted sound 

levels from an airgun array. Ramp-up 

begins by first activating a single airgun 

of the smallest volume, followed by 

doubling the number of active elements 

in stages until the full complement of an 

array’s airguns are active. Each stage 

should be approximately the same 

duration, and the total duration should 

not be less than approximately 20 

minutes. The intent of pre-clearance 

observation (30 minutes) is to ensure no 

protected species are observed within 

the buffer zone prior to the beginning of 

ramp-up. During pre-clearance is the 

only time observations of protected 

species in the buffer zone would 

prevent operations (i.e., the beginning of 

ramp-up). The intent of ramp-up is to 

warn protected species of pending 

seismic operations and to allow 

sufficient time for those animals to leave 

the immediate vicinity. A ramp-up 

procedure, involving a step-wise 

increase in the number of airguns firing 

and total array volume until all 

operational airguns are activated and 

the full volume is achieved, is required 

at all times as part of the activation of 

the acoustic source. All operators must 

adhere to the following pre-clearance 

and ramp-up requirements: 

• The operator must notify a 

designated PSO of the planned start of 

ramp-up as agreed upon with the lead 

PSO; the notification time should not be 

less than 60 minutes prior to the 

planned ramp-up in order to allow the 

PSOs time to monitor the exclusion and 

buffer zones for 30 minutes prior to the 

initiation of ramp-up (pre-clearance); 

• Ramp-ups must be scheduled so as 

to minimize the time spent with the 

source activated prior to reaching the 

designated run-in; 

• One of the PSOs conducting preclearance observations must be notified 

again immediately prior to initiating 

ramp-up procedures and the operator 

must receive confirmation from the PSO 

to proceed; 

• Ramp-up may not be initiated if any 

marine mammal is within the applicable 

exclusion or buffer zone. If a marine 

mammal is observed within the 

applicable exclusion zone or the buffer 

zone during the 30 minute pre-clearance 

period, ramp-up may not begin until the 

animal(s) has been observed exiting the 

zones or until an additional time period 

has elapsed with no further sightings 

(15 minutes for small odontocetes and 

pinnipeds, and 30 minutes for all 

mysticetes and all other odontocetes, 

including sperm whales, pygmy sperm 

whales, dwarf sperm whales, beaked 

whales, pilot whales, false killer whales, 

and Risso’s dolphins); 

• Ramp-up must begin by activating a 

single airgun of the smallest volume in 

the array and must continue in stages by 

doubling the number of active elements 

at the commencement of each stage, 

with each stage of approximately the 

same duration. Duration must not be 

less than 20 minutes. The operator must 

provide information to the PSO 

documenting that appropriate 

procedures were followed; 

• PSOs must monitor the exclusion 

and buffer zones during ramp-up, and 

ramp-up must cease and the source 

must be shut down upon detection of a 

marine mammal within the applicable 

exclusion zone. Once ramp-up has 

begun, detections of marine mammals 

within the buffer zone do not require 

shutdown, but such observation must be 

communicated to the operator to 

prepare for the potential shutdown; 

• Ramp-up may occur at times of 

poor visibility, including nighttime, if 

appropriate acoustic monitoring has 

occurred with no detections in the 30 

minutes prior to beginning ramp-up. 

Acoustic source activation may only 

occur at times of poor visibility where 

operational planning cannot reasonably 

avoid such circumstances; 

• If the acoustic source is shut down 

for brief periods (i.e., less than 30 

minutes) for reasons other than that 

described for shutdown (e.g., 

mechanical difficulty), it may be 

activated again without ramp-up if PSOs 

have maintained constant visual and/or 

acoustic observation and no visual or 

acoustic detections of marine mammals 

have occurred within the applicable 

exclusion zone. For any longer 

shutdown, pre-clearance observation 

and ramp-up are required. For any 

shutdown at night or in periods of poor 

visibility (e.g., BSS 4 or greater), rampup is required, but if the shutdown 

period was brief and constant 

observation was maintained, preclearance watch of 30 minutes is not 

required; and 

• Testing of the acoustic source 

involving all elements requires rampup. Testing limited to individual source 

elements or strings does not require 

ramp-up but does require pre-clearance 

of 30 min. 

Shutdown 

The shutdown of an airgun array 

requires the immediate de-activation of 

all individual airgun elements of the 

array. Any PSO on duty has the 

authority to delay the start of survey 

operations or to call for shutdown of the 

acoustic source if a marine mammal is 

detected within the applicable EZ. The 

operator must also establish and 

maintain clear lines of communication 

directly between PSOs on duty and 

crew controlling the acoustic source to 

ensure that shutdown commands are 

conveyed swiftly while allowing PSOs 

to maintain watch. When both visual 

and acoustic PSOs are on duty, all 

detections must be immediately 

communicated to the remainder of the 

on-duty PSO team for potential 

verification of visual observations by the 

acoustic PSO or of acoustic detections 

by visual PSOs. When the airgun array 

is active (i.e., anytime one or more 

airguns is active, including during 

ramp-up) and (1) a marine mammal 

appears within or enters the applicable 

exclusion zone and/or (2) a marine 

mammal (other than delphinids, see 

below) is detected acoustically and 

localized within the applicable 

exclusion zone, the acoustic source 

must be shut down. When shutdown is 

called for by a PSO, the acoustic source 

must be immediately deactivated and 

any dispute resolved only following 

deactivation. Additionally, shutdown 

must occur whenever PAM alone 

(without visual sighting), confirms 

presence of marine mammal(s) in the 

EZ. If the acoustic PSO cannot confirm 

presence within the EZ, visual PSOs 

must be notified but shutdown is not 

required. L–DEO must also implement 

shutdown of the airgun array if killer 

whale vocalizations are detected, 

regardless of localization. 

Following a shutdown, airgun activity 

must not resume until the marine 

mammal has cleared the 500-m EZ. The 

animal would be considered to have 

cleared the 500-m EZ if it is visually 

observed to have departed the 500-m 

EZ, or it has not been seen within the 

500-m EZ for 15 min in the case of small 

odontocetes and pinnipeds, or 30 min in 

the case of mysticetes and large 

odontocetes, including sperm whales, 

pygmy sperm whales, dwarf sperm 

whales, pilot whales, beaked whales, 

killer whales, false killer whales, and 

Risso’s dolphins. 

The shutdown requirement can be 

waived for small dolphins if an 

individual is visually detected within 

the exclusion zone. As defined here, the 

small dolphin group is intended to 

encompass those members of the Family 

Delphinidae most likely to voluntarily 

approach the source vessel for purposes 

of interacting with the vessel and/or 

airgun array (e.g., bow riding). This 

exception to the shutdown requirement 

29124 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

applies solely to specific genera of small 

dolphins—Tursiops, Delphinus, 

Stenella, Lagenorhynchus, and 

Lissodelphis. 

We include this small dolphin 

exception because shutdown 

requirements for small dolphins under 

all circumstances represent 

practicability concerns without likely 

commensurate benefits for the animals 

in question. Small dolphins are 

generally the most commonly observed 

marine mammals in the specific 

geographic region and would typically 

be the only marine mammals likely to 

intentionally approach the vessel. As 

described above, auditory injury is 

extremely unlikely to occur for midfrequency cetaceans (e.g., delphinids), 

as this group is relatively insensitive to 

sound produced at the predominant 

frequencies in an airgun pulse while 

also having a relatively high threshold 

for the onset of auditory injury (i.e., 

permanent threshold shift). 

A large body of anecdotal evidence 

indicates that small dolphins commonly 

approach vessels and/or towed arrays 

during active sound production for 

purposes of bow riding, with no 

apparent effect observed in those 

delphinoids (e.g., Barkaszi et al., 2012). 

The potential for increased shutdowns 

resulting from such a measure would 

require the R/V Langseth to revisit the 

missed track line to reacquire data, 

resulting in an overall increase in the 

total sound energy input to the marine 

environment and an increase in the total 

duration over which the survey is active 

in a given area. Although other midfrequency hearing specialists (e.g., large 

delphinoids) are no more likely to incur 

auditory injury than are small dolphins, 

they are much less likely to approach 

vessels. Therefore, retaining a shutdown 

requirement for large delphinoids 

would not have similar impacts in terms 

of either practicability for the applicant 

or corollary increase in sound energy 

output and time on the water. We do 

anticipate some benefit for a shutdown 

requirement for large delphinoids in 

that it simplifies somewhat the total 

range of decision-making for PSOs and 

may preclude any potential for 

physiological effects other than to the 

auditory system as well as some more 

severe behavioral reactions for any such 

animals in close proximity to the source 

vessel. 

Visual PSOs must use best 

professional judgment in making the 

decision to call for a shutdown if there 

is uncertainty regarding identification 

(i.e., whether the observed marine 

mammal(s) belongs to one of the 

delphinid genera for which shutdown is 

waived or one of the species with a 

larger exclusion zone). 

Upon implementation of shutdown, 

the source may be reactivated after the 

marine mammal(s) has been observed 

exiting the applicable exclusion zone 

(i.e., animal is not required to fully exit 

the buffer zone where applicable) or 

following 15 minutes for small 

odontocetes and pinnipeds, and 30 

minutes for mysticetes and all other 

odontocetes, including sperm whales, 

pygmy sperm whales, dwarf sperm 

whales, beaked whales, pilot whales, 

and Risso’s dolphins, with no further 

observation of the marine mammal(s). 

L–DEO must implement shutdown if 

a marine mammal species for which 

take was not authorized, or a species for 

which authorization was granted but the 

takes have been met, approaches the 

Level A or Level B harassment zones. L– 

DEO must also implement shutdown if 

any of the following are observed at any 

distance: 

• Any large whale (defined as a 

sperm whale or any mysticete species) 

with a calf (defined as an animal less 

than two-thirds the body size of an adult 

observed to be in close association with 

an adult; 

• An aggregation of six or more large 

whales; 

• A North Pacific right whale; and/or 

• A killer whale of any ecotype. 

Vessel Strike Avoidance 

These measures apply to all vessels 

associated with the planned survey 

activity; however, we note that these 

requirements do not apply in any case 

where compliance would create an 

imminent and serious threat to a person 

or vessel or to the extent that a vessel 

is restricted in its ability to maneuver 

and, because of the restriction, cannot 

comply. These measures include the 

following: 

1. Vessel operators and crews must 

maintain a vigilant watch for all marine 

mammals and slow down, stop their 

vessel, or alter course, as appropriate 

and regardless of vessel size, to avoid 

striking any marine mammal. A single 

marine mammal at the surface may 

indicate the presence of submerged 

animals in the vicinity of the vessel; 

therefore, precautionary measures 

should be exercised when an animal is 

observed. A visual observer aboard the 

vessel must monitor a vessel strike 

avoidance zone around the vessel 

(specific distances detailed below), to 

ensure the potential for strike is 

minimized. Visual observers monitoring 

the vessel strike avoidance zone can be 

either third-party observers or crew 

members, but crew members 

responsible for these duties must be 

provided sufficient training to 

distinguish marine mammals from other 

phenomena and broadly to identify a 

marine mammal to broad taxonomic 

group (i.e., as a large whale or other 

marine mammal); 

2. Vessel speeds must be reduced to 

10 knots or less when mother/calf pairs, 

pods, or large assemblages of any 

marine mammal are observed near a 

vessel; 

3. All vessels must maintain a 

minimum separation distance of 100 m 

from large whales (i.e., sperm whales 

and all mysticetes); 

4. All vessels must attempt to 

maintain a minimum separation 

distance of 50 m from all other marine 

mammals, with an exception made for 

those animals that approach the vessel; 

and 

5. When marine mammals are sighted 

while a vessel is underway, the vessel 

should take action as necessary to avoid 

violating the relevant separation 

distance (e.g., attempt to remain parallel 

to the animal’s course, avoid excessive 

speed or abrupt changes in direction 

until the animal has left the area). If 

marine mammals are sighted within the 

relevant separation distance, the vessel 

should reduce speed and shift the 

engine to neutral, not engaging the 

engines until animals are clear of the 

area. This recommendation does not 

apply to any vessel towing gear. 

Operational Restrictions 

While the R/V Langseth is surveying 

in waters 200 m deep or less along the 

coast between Tillamook Head, Oregon 

and Barkley Sound, British Columbia 

(between latitudes 45.9460903° N and 

48.780291° N), and within the 

boundaries of Olympic Coast National 

Marine Sanctuary, survey operations 

must occur in daylight hours only (i.e., 

from 30 minutes prior to sunrise 

through 30 minutes following sunset) to 

ensure the ability to use visual 

observation as a detection-based 

mitigation tool and to implement 

shutdown procedures for species or 

situations with additional shutdown 

requirements outlined above (e.g., killer 

whale of any ecotype, North Pacific 

right whale, aggregation of six or more 

large whales, large whale with a calf). 

The proposed IHA included this 

requirement to operate only during 

daylight hours in waters 200 m deep or 

less throughout the entire survey area. 

We have revised that requirement to 

apply only between Tillamook Head 

and Barkley Sound and within the 

boundaries of Olympic Coast National 

Marine Sanctuary because those are the 

areas with the highest expected 

Southern Resident killer whale 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29125 

occurrence, and we determined that 

requiring this operational restriction 

throughout the entire survey area was 

not practicable, in consideration of cost 

and vessel availability concerns. 

Communication 

Each day of survey operations, L–DEO 

must contact NMFS Northwest Fisheries 

Science Center, NMFS West Coast 

Region, The Whale Museum, Orca 

Network, Canada’s DFO, Olympic Coast 

National Marine Sanctuary, and/or other 

sources to obtain near real-time 

reporting for the whereabouts of 

Southern Resident killer whales. 

Mitigation Measures in Canadian 

Waters 

As stated above, NMFS cannot 

authorize the incidental take of marine 

mammals in the territorial seas of 

foreign nations, as the MMPA does not 

apply in those waters. Therefore, the 

mitigation requirements described 

above do not apply within Canadian 

territorial waters. The MMPA is 

applicable in the EEZs of foreign 

nations, and therefore, the mitigation 

measures above apply within the 

Canadian EEZ. However, L–DEO also 

consulted with Canada’s DFO under the 

Canada Species at Risk Act and must 

also comply with DFO’s mitigation 

requirements within the Canadian EEZ 

in order to avoid causing the death of 

fish or marine mammals and/or the 

harmful alteration, disruption, or 

destruction of fish habitat, or causing 

prohibited effects to aquatic species at 

risk. Within the Canadian EEZ, L–DEO 

must: 

• Conduct seismic survey activities 

outside of designated Killer Whale 

Critical Habitat (KWCH) with a setback 

that ensures that the estimated sound 

pressure level has diminished to ≤160 

dB rms re: 1 mPa at the boundary of 

KWCH; 

• Initiate an immediate and complete 

shutdown of the airgun array if a killer 

whale (all ecotypes), North Pacific right 

whale, whale with calf (any species) or 

aggregation of whales (any species) is 

observed; 

• Initiate an immediate and complete 

shutdown of the airgun array if a sperm 

whale or a beaked whale (any species) 

is sighted within 1,500 m of the airgun 

array; 

• For other observations of marine 

mammals, initiate an immediate and 

complete shutdown of the airgun array 

if these animals are observed within an 

established EZ with a radius of 1,000 m; 

• Refrain from conducting seismic 

surveys in waters less than 100 m in 

depth; 

• Conduct seismic surveys in waters 

100 to 200 m deep during daylight 

hours only, with a second vessel having 

two marine mammal observers on 

watch, positioned 5 km ahead of the 

R/V Langseth; 

• Combine enhanced visual 

observations (e.g., reticle and big-eye 

binoculars, night vision devices and 

digital cameras) with non-visual 

detection methods (e.g., infrared 

technology (FLIR) and passive acoustic 

monitoring) to increase the likelihood of 

detecting marine mammals during ramp 

up, Beaufort sea states >3, and nighttime 

survey operations; and 

• Monitor the established EZ with a 

radius of 1,000 m for 60 minutes prior 

to initial start-up of the airgun array or 

resumption of operations following a 

complete shutdown to allow for the 

detection of deep diving animals. 

While operating within the Canadian 

EEZ but outside Canadian territorial 

waters, if mitigation requirements in the 

IHA differ from the requirements 

established by DFO, L–DEO must 

adhere to the most protective measure 

(e.g., larger EZ, visual monitoring 

procedures). 

Mitigation Measures Considered But 

Eliminated 

As stated above, in determining 

appropriate mitigation measures, NMFS 

considers the practicability of the 

measures for applicant implementation, 

which may include such things as cost 

or impact on operations. NMFS has 

proposed expanding critical habitat for 

Southern Resident killer whales to 

include marine waters between the 6.1- 

m depth contour and the 200-m depth 

contour from the U.S. international 

border with Canada south to Point Sur, 

California (84 FR 49214; September 19, 

2019). Though the proposed expansion 

has not been finalized, due to the 

habitat features of the area and the 

higher likelihood of occurrence within 

the area, NMFS considered 

implementing a closure area and 

prohibiting L–DEO from conducting 

survey operations between the 200-m 

isobath and the coastline. However, this 

measure was eliminated from 

consideration because the closure 

would not be practicable for L–DEO, as 

the primary purpose of their survey is 

to investigate the geologic features that 

occur within that area. Therefore, NMFS 

has not prohibited L–DEO from 

operating in waters within the 200-m 

isobath for this survey. 

We have carefully evaluated the suite 

of mitigation measures described here 

and considered a range of other 

measures in the context of ensuring that 

we prescribe the means of effecting the 

least practicable adverse impact on the 

affected marine mammal species and 

stocks and their habitat. Based on our 

evaluation of the proposed measures, as 

well as other measures considered by 

NMFS described above, 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. 

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 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, 

29126 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

acoustic habitat, or other important 

physical components of marine 

mammal habitat); and 

• Mitigation and monitoring 

effectiveness. 

Vessel-Based Visual Monitoring 

As described above, PSO observations 

must take place during daytime airgun 

operations. During seismic operations, 

at least five visual PSOs must be based 

aboard the R/V Langseth. Two visual 

PSOs must be on duty at all time during 

daytime hours, with an additional two 

PSOs on duty aboard a second scout 

vessel at all times during daylight hours 

when operating in waters shallower 

than 200 m. Monitoring must be 

conducted in accordance with the 

following requirements: 

• The operator must provide PSOs 

with bigeye binoculars (e.g., 25 x 150; 

2.7 view angle; individual ocular focus; 

height control) of appropriate quality 

(i.e., Fujinon or equivalent) solely for 

PSO use. These must be pedestalmounted on the deck at the most 

appropriate vantage point that provides 

for optimal sea surface observation, PSO 

safety, and safe operation of the vessel; 

and 

• The operator must work with the 

selected third-party observer provider to 

ensure PSOs have all equipment 

(including backup equipment) needed 

to adequately perform necessary tasks, 

including accurate determination of 

distance and bearing to observed marine 

mammals. 

PSOs must have the following 

requirements and qualifications: 

• PSOs must be independent, 

dedicated, trained visual and acoustic 

PSOs and must be employed by a thirdparty observer provider; 

• PSOs must have no tasks other than 

to conduct observational effort (visual or 

acoustic), collect data, and 

communicate with and instruct relevant 

vessel crew with regard to the presence 

of protected species and mitigation 

requirements (including brief alerts 

regarding maritime hazards); 

• PSOs must have successfully 

completed an approved PSO training 

course appropriate for their designated 

task (visual or acoustic). Acoustic PSOs 

are required to complete specialized 

training for operating PAM systems and 

are encouraged to have familiarity with 

the vessel with which they will be 

working; 

• PSOs can act as acoustic or visual 

observers (but not at the same time) as 

long as they demonstrate that their 

training and experience are sufficient to 

perform the task at hand; 

• NMFS must review and approve 

PSO resumes accompanied by a relevant 

training course information packet that 

includes the name and qualifications 

(i.e., experience, training completed, or 

educational background) of the 

instructor(s), the course outline or 

syllabus, and course reference material 

as well as a document stating successful 

completion of the course; 

• NMFS shall have one week to 

approve PSOs from the time that the 

necessary information is submitted, 

after which PSOs meeting the minimum 

requirements shall automatically be 

considered approved; 

• PSOs must successfully complete 

relevant training, including completion 

of all required coursework and passing 

(80 percent or greater) a written and/or 

oral examination developed for the 

training program; 

• PSOs must have successfully 

attained a bachelor’s degree from an 

accredited college or university with a 

major in one of the natural sciences, a 

minimum of 30 semester hours or 

equivalent in the biological sciences, 

and at least one undergraduate course in 

math or statistics; and 

• The educational requirements may 

be waived if the PSO has acquired the 

relevant skills through alternate 

experience. Requests for such a waiver 

must be submitted to NMFS and must 

include written justification. Requests 

shall be granted or denied (with 

justification) by NMFS within one week 

of receipt of submitted information. 

Alternate experience that may be 

considered includes, but is not limited 

to (1) secondary education and/or 

experience comparable to PSO duties; 

(2) previous work experience 

conducting academic, commercial, or 

government-sponsored protected 

species surveys; or (3) previous work 

experience as a PSO; the PSO should 

demonstrate good standing and 

consistently good performance of PSO 

duties. 

For data collection purposes, PSOs 

must use standardized data collection 

forms, whether hard copy or electronic. 

PSOs must record detailed information 

about any implementation of mitigation 

requirements, including the distance of 

animals to the acoustic source and 

description of specific actions that 

ensued, the behavior of the animal(s), 

any observed changes in behavior before 

and after implementation of mitigation, 

and if shutdown was implemented, the 

length of time before any subsequent 

ramp-up of the acoustic source. If 

required mitigation was not 

implemented, PSOs should record a 

description of the circumstances. At a 

minimum, the following information 

must be recorded: 

• Vessel names (source vessel and 

other vessels associated with survey) 

and call signs; 

• PSO names and affiliations; 

• Dates of departures and returns to 

port with port name; 

• Date and participants of PSO 

briefings; 

• Dates and times (Greenwich Mean 

Time) of survey effort and times 

corresponding with PSO effort; 

• Vessel location (latitude/longitude) 

when survey effort began and ended and 

vessel location at beginning and end of 

visual PSO duty shifts; 

• Vessel heading and speed at 

beginning and end of visual PSO duty 

shifts and upon any line change; 

• Environmental conditions while on 

visual survey (at beginning and end of 

PSO shift and whenever conditions 

changed significantly), including BSS 

and any other relevant weather 

conditions including cloud cover, fog, 

sun glare, and overall visibility to the 

horizon; 

• Factors that may have contributed 

to impaired observations during each 

PSO shift change or as needed as 

environmental conditions changed (e.g., 

vessel traffic, equipment malfunctions); 

and 

• Survey activity information, such as 

acoustic source power output while in 

operation, number and volume of 

airguns operating in the array, tow 

depth of the array, and any other notes 

of significance (i.e., pre-clearance, rampup, shutdown, testing, shooting, rampup completion, end of operations, 

streamers, etc.). 

The following information should be 

recorded upon visual observation of any 

protected species: 

• Watch status (sighting made by PSO 

on/off effort, opportunistic, crew, 

alternate vessel/platform); 

• PSO who sighted the animal; 

• Time of sighting; 

• Vessel location at time of sighting; 

• Water depth; 

• Direction of vessel’s travel (compass 

direction); 

• Direction of animal’s travel relative 

to the vessel; 

• Pace of the animal; 

• Estimated distance to the animal 

and its heading relative to vessel at 

initial sighting; 

• Identification of the animal (e.g., 

genus/species, lowest possible 

taxonomic level, or unidentified) and 

the composition of the group if there is 

a mix of species; 

• Estimated number of animals (high/ 

low/best); 

• Estimated number of animals by 

cohort (adults, yearlings, juveniles, 

calves, group composition, etc.); 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29127 

• Description (as many distinguishing 

features as possible of each individual 

seen, including length, shape, color, 

pattern, scars or markings, shape and 

size of dorsal fin, shape of head, and 

blow characteristics); 

• Detailed behavior observations (e.g., 

number of blows/breaths, number of 

surfaces, breaching, spyhopping, diving, 

feeding, traveling; as explicit and 

detailed as possible; note any observed 

changes in behavior); 

• Animal’s closest point of approach 

(CPA) and/or closest distance from any 

element of the acoustic source; 

• Platform activity at time of sighting 

(e.g., deploying, recovering, testing, 

shooting, data acquisition, other); and 

• Description of any actions 

implemented in response to the sighting 

(e.g., delays, shutdown, ramp-up) and 

time and location of the action. 

If a marine mammal is detected while 

using the PAM system, the following 

information should be recorded: 

• An acoustic encounter 

identification number, and whether the 

detection was linked with a visual 

sighting; 

• Date and time when first and last 

heard; 

• Types and nature of sounds heard 

(e.g., clicks, whistles, creaks, burst 

pulses, continuous, sporadic, strength of 

signal); and 

• Any additional information 

recorded such as water depth of the 

hydrophone array, bearing of the animal 

to the vessel (if determinable), species 

or taxonomic group (if determinable), 

spectrogram screenshot, and any other 

notable information. 

Reporting 

A report must be submitted to NMFS 

within 90 days after the end of the 

cruise. The report must describe the 

operations that were conducted and 

sightings of marine mammals near the 

operations. The report must provide full 

documentation of methods, results, and 

interpretation pertaining to all 

monitoring. The 90-day report must 

summarize the dates and locations of 

seismic operations, and all marine 

mammal sightings (dates, times, 

locations, activities, associated seismic 

survey activities). The report must also 

include estimates of the number and 

nature of exposures that occurred above 

the harassment threshold based on PSO 

observations and including an estimate 

of those that were not detected, in 

consideration of both the characteristics 

and behaviors of the species of marine 

mammals that affect detectability, as 

well as the environmental factors that 

affect detectability. 

The draft report must also include 

geo-referenced time-stamped vessel 

tracklines for all time periods during 

which airguns were operating. 

Tracklines should include points 

recording any change in airgun status 

(e.g., when the airguns began operating, 

when they were turned off, or when 

they changed from full array to single 

gun or vice versa). GIS files must be 

provided in ESRI shapefile format and 

include the UTC date and time, latitude 

in decimal degrees, and longitude in 

decimal degrees. All coordinates must 

be referenced to the WGS84 geographic 

coordinate system. In addition to the 

report, all raw observational data must 

be made available to NMFS. The report 

must summarize the information 

submitted in interim monthly reports as 

well as additional data collected as 

described above and in the IHA. A final 

report must be submitted within 30 days 

following resolution of any comments 

on the draft report. 

Reporting Injured or Dead Marine 

Mammals 

Discovery of injured or dead marine 

mammals—In the event that personnel 

involved in survey activities covered by 

the authorization discover an injured or 

dead marine mammal, the L–DEO must 

report the incident to the Office of 

Protected Resources (OPR), NMFS and 

to the NMFS West Coast Regional 

Stranding Coordinator as soon as 

feasible. 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. 

Vessel strike—In the event of a ship 

strike of a marine mammal by any vessel 

involved in the activities covered by the 

authorization, L–DEO must report the 

incident to OPR, NMFS and to the 

NMFS West Coast Regional Stranding 

Coordinator as soon as feasible. The 

report must include the following 

information: 

• Time, date, and location (latitude/ 

longitude) of the incident; 

• Vessel’s speed during and leading 

up to the incident; 

• Vessel’s course/heading and what 

operations were being conducted (if 

applicable); 

• Status of all sound sources in use; 

• Description of avoidance measures/ 

requirements that were in place at the 

time of the strike and what additional 

measures were taken, if any, to avoid 

strike; 

• Environmental conditions (e.g., 

wind speed and direction, Beaufort sea 

state, cloud cover, visibility) 

immediately preceding the strike; 

• Species identification (if known) or 

description of the animal(s) involved; 

• Estimated size and length of the 

animal that was struck 

• Description of the behavior of the 

animal immediately preceding and 

following the strike; 

• If available, description of the 

presence and behavior of any other 

marine mammals present immediately 

preceding the strike; 

• Estimated fate of the animal (e.g., 

dead, injured but alive, injured and 

moving, blood or tissue observed in the 

water, status unknown, disappeared); 

and 

• To the extent practicable, 

photographs or video footage of the 

animal(s). 

Actions To Minimize Additional Harm 

to Live-Stranded (or Milling) Marine 

Mammals 

In the event of a live stranding (or 

near-shore atypical milling) event 

within 50 km of the survey operations, 

where the NMFS stranding network is 

engaged in herding or other 

interventions to return animals to the 

water, the Director of OPR, NMFS (or 

designee) will advise L–DEO of the need 

to implement shutdown procedures for 

all active acoustic sources operating 

within 50 km of the stranding. 

Shutdown procedures for live stranding 

or milling marine mammals include the 

following: If at any time, the marine 

mammal the marine mammal(s) die or 

are euthanized, or if herding/ 

intervention efforts are stopped, the 

Director of OPR, NMFS (or designee) 

will advise the IHA-holder that the 

shutdown around the animals’ location 

is no longer needed. Otherwise, 

shutdown procedures must remain in 

effect until the Director of OPR, NMFS 

(or designee) determines and advises L– 

DEO that all live animals involved have 

left the area (either of their own volition 

or following an intervention). 

If further observations of the marine 

mammals indicate the potential for restranding, additional coordination with 

the IHA-holder will be required to 

determine what measures are necessary 

to minimize that likelihood (e.g., 

29128 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

extending the shutdown or moving 

operations farther away) and to 

implement those measures as 

appropriate. 

Additional Information Requests—If 

NMFS determines that the 

circumstances of any marine mammal 

stranding found in the vicinity of the 

activity suggest investigation of the 

association with survey activities is 

warranted, and an investigation into the 

stranding is being pursued, NMFS will 

submit a written request to L–DEO 

indicating that the following initial 

available information must be provided 

as soon as possible, but no later than 7 

business days after the request for 

information: 

• Status of all sound source use in the 

48 hours preceding the estimated time 

of stranding and within 50 km of the 

discovery/notification of the stranding 

by NMFS; and 

• If available, description of the 

behavior of any marine mammal(s) 

observed preceding (i.e., within 48 

hours and 50 km) and immediately after 

the discovery of the stranding. 

In the event that the investigation is 

still inconclusive, the investigation of 

the association of the survey activities is 

still warranted, and the investigation is 

still being pursued, NMFS may provide 

additional information requests, in 

writing, regarding the nature and 

location of survey operations prior to 

the time period above. 

Reporting Species of Concern 

To support NMFS’s goal of improving 

our understanding of occurrence of 

marine mammal species or stocks in the 

area (e.g., presence, abundance, 

distribution, density), L–DEO must 

immediately report observations of 

Southern Resident killer whales and 

North Pacific right whales to OPR, 

NMFS. L–DEO must also immediately 

report all sightings of Southern Resident 

killer whales and North Pacific right 

whales within Olympic Coast National 

Marine Sanctuary to the Sanctuary. 

Negligible Impact Analysis and 

Determination 

NMFS has defined negligible impact 

as an impact resulting from the 

specified activity that cannot be 

reasonably expected to, and is not 

reasonably likely to, adversely affect the 

species or stock through effects on 

annual rates of recruitment or survival 

(50 CFR 216.103). A negligible impact 

finding is based on the lack of likely 

adverse effects on annual rates of 

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

of takes alone is not enough information 

on which to base an impact 

determination. In addition to 

considering estimates of the number of 

marine mammals that might be ‘‘taken’’ 

through harassment, NMFS considers 

other factors, such as the likely nature 

of any responses (e.g., intensity, 

duration), the context of any responses 

(e.g., critical reproductive time or 

location, migration), as well as effects 

on habitat, and the likely effectiveness 

of the mitigation. We also assess the 

number, intensity, and context of 

estimated takes by evaluating this 

information relative to population 

status. Consistent with the 1989 

preamble for NMFS’s implementing 

regulations (54 FR 40338; September 29, 

1989), the impacts from other past and 

ongoing anthropogenic activities are 

incorporated into this analysis via their 

impacts on the environmental baseline 

(e.g., as reflected in the regulatory status 

of the species, population size and 

growth rate where known, ongoing 

sources of human-caused mortality, or 

ambient noise levels). 

To avoid repetition, our analysis 

applies to all species listed in Tables 10 

and 11, given that NMFS expects the 

anticipated effects of the planned 

geophysical survey to be similar in 

nature. Where there are meaningful 

differences between species or stocks, or 

groups of species, in anticipated 

individual responses to activities, 

impact of expected take on the 

population due to differences in 

population status, or impacts on habitat, 

NMFS has identified species-specific 

factors to inform the analysis. As 

described above, we have authorized 

only the takes estimated to occur 

outside of Canadian territorial waters 

(Table 10); however, for the purposes of 

our negligible impact analysis and 

determination, we consider the total 

number of takes that are anticipated to 

occur as a result of the entire survey 

(including the portion of the survey that 

would occur within the Canadian 

territorial waters (approximately six 

percent of the survey) (Table 11). 

TABLE 11—TOTAL ESTIMATED TAKE INCLUDING CANADIAN TERRITORIAL WATERS

Species 

Estimated take 

(excluding Canadian territorial 

waters) 

Estimated take 

(within Canadian territorial 

waters) 

Total estimated take 

Level B Level A Level B Level A 

Level B Level A 

LF Cetaceans: 

Humpback whale .............................. 112 29 21 1 133 30 

Blue whale ........................................ 40 11 7 1 47 11 

Fin whale .......................................... 94 1 2 0 96 1 

Sei whale .......................................... 30 2 2 0 31 2 

Minke whale ...................................... 96 7 6 0 101 7 

Gray whale ........................................ 43 1 23 1 66 2 

MF Cetaceans: 

Sperm whale ..................................... 72 0 1 0 73 0 

Baird’s beaked whale ....................... 84 0 1 0 85 0 

Small beaked whale ......................... 242 0 5 0 247 0 

Bottlenose dolphin ............................ 1 0 0 0 1 0 

Striped dolphin .................................. 7 0 0 0 7 0 

Short-beaked common dolphin ......... 112 0 4 0 116 0 

Pacific white-sided dolphin ............... 6093 0 333 0 6426 0 

Northern right-whale dolphin ............ 4320 0 118 0 4438 0 

Risso’s dolphin .................................. 1669 0 145 0 1814 0 

False killer whale .............................. 5 0 0 0 5 0 

Killer whale (Southern Resident) ...... 10 0 1 0 11 0 

Killer whale (Northern Resident) ......

Killer whale (West Coast Transient)

Killer whale (Offshore) ...................... 73 0 4 0 77 0 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29129 

TABLE 11—TOTAL ESTIMATED TAKE INCLUDING CANADIAN TERRITORIAL WATERS—Continued 

Species 

Estimated take 

(excluding Canadian territorial 

waters) 

Estimated take 

(within Canadian territorial 

waters) 

Total estimated take 

Level B Level A Level B Level A 

Level B Level A 

Short-finned pilot whale .................... 20 0 1 0 21 0 

HF Cetaceans: 

Pygmy/dwarf sperm whale ............... 125 5 8 0 134 6 

Dall’s porpoise .................................. 9762 488 696 23 10457 511 

Harbor porpoise ................................ 7958 283 2403 87 10361 369 

Otariid Pinnipeds: 

Northern fur seal ............................... 4424 0 54 0 4478 0 

Guadalupe fur seal ........................... 2048 0 113 0 2161 0 

California sea lion ............................. 889 0 137 0 1026 0 

Steller sea lion .................................. 7504 0 1920 0 9424 0 

Phocid Pinnipeds: 

Northern elephant seal ..................... 2754 0 164 0 2918 0 

Harbor seal ....................................... 3887 0 1623 0 5510 0 

NMFS does not anticipate that serious 

injury or mortality will occur as a result 

of L–DEO’s planned survey, even in the 

absence of mitigation, and none are 

authorized. As discussed in the 

Potential Effects section of the notice of 

proposed IHA (85 FR 19580; April 7, 

2020), non-auditory physical effects, 

stranding, and vessel strike are not 

expected to occur. 

We have authorized a limited number 

of instances of Level A harassment of 

nine species (low- and high-frequency 

cetacean hearing groups only) and Level 

B harassment of 31 marine mammal 

species. However, we believe that any 

PTS incurred in marine mammals as a 

result of the planned activity would be 

in the form of only a small degree of 

PTS, not total deafness, because of the 

constant movement relative to each 

other of both the R/V Langseth and of 

the marine mammals in the project 

areas, as well as the fact that the vessel 

is not expected to remain in any one 

area in which individual marine 

mammals would be expected to 

concentrate for an extended period of 

time (i.e., since the duration of exposure 

to loud sounds will be relatively short) 

and, further, would be unlikely to affect 

the fitness of any individuals. Also, as 

described above, we expect that marine 

mammals would be likely to move away 

from a sound source that represents an 

aversive stimulus, especially at levels 

that would be expected to result in PTS, 

given sufficient notice of the R/V 

Langseth’s approach due to the vessel’s 

relatively low speed when conducting 

seismic surveys. We expect that the 

majority of takes would be in the form 

of short-term Level B behavioral 

harassment in the form of temporary 

avoidance of the area or decreased 

foraging (if such activity were 

occurring), reactions that are considered 

to be of low severity and with no lasting 

biological consequences (e.g., Southall 

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

Potential impacts to marine mammal 

habitat were discussed in detail in the 

Potential Effects of the Specified 

Activity on Marine Mammals and their 

Habitat section of the notice of 

proposed IHA (85 FR 19580; April 7, 

2020). Marine mammal habitat may be 

impacted by elevated sound levels, but 

these impacts would be temporary. Prey 

species are mobile and are broadly 

distributed throughout the project areas; 

therefore, marine mammals that may be 

temporarily displaced during survey 

activities are expected to be able to 

resume foraging once they have moved 

away from areas with disturbing levels 

of underwater noise. Because of the 

relatively short duration (37 days) and 

temporary nature of the disturbance, the 

availability of similar habitat and 

resources in the surrounding area, the 

impacts to marine mammals and the 

food sources that they utilize are not 

expected to cause significant or longterm consequences for individual 

marine mammals or their populations. 

The tracklines of this survey either 

traverse or are proximal to BIAs for 

humpback and gray whales (Ferguson et 

al., 2015). The entire U.S. West Coast 

within 47 km of the coast is a BIA for 

migrating gray whale potential presence 

from January to July and October to 

December. The BIA for northbound gray 

whale migration is broken into two 

phases, Phase A (within 8 km of shore) 

and Phase B (within 5 km of shore), 

which are active from January to July 

and March to July, respectively. The 

BIA for southbound migration includes 

waters within 10 km of shore and is 

active from October to March. There are 

four gray whale feeding BIAs within the 

survey area: The Grays Harbor gray 

whale feeding BIA is used between 

April and November; the Northwest 

Washington gray whale feeding BIA is 

used between May and November; and 

the Depoe Bay and Cape Blanco and 

Orford Reef gray whale feeding BIAs off 

Oregon are each used between June and 

November. There are also two 

humpback whale feeding BIAs within 

the survey area: The Stonewall and 

Heceta Bank humpback whale feeding 

BIA off central Oregon and the northern 

Washington BIA off the Washington 

Olympic Peninsula are each used 

between May and November. 

For the humpback whale feeding and 

gray whale feeding and northbound 

migration BIAs, L–DEO’s survey 

beginning in June 2021 could overlap 

with a period where BIAs represent an 

important habitat. However, only a 

portion of seismic survey days would 

actually occur in or near these BIAs, and 

all survey efforts would be completed 

by mid-July, still in the early window of 

primary use for these BIAs. Gray whales 

are most commonly seen migrating 

northward between March and May and 

southward between November and 

January. As planned, there is no 

possibility that L–DEO’s survey impacts 

the southern migration, and presence of 

northern migrating individuals should 

be below peak during survey operations 

beginning in June 2021. 

Although migrating gray whales may 

slightly alter their course in response to 

the survey, the exposure would not 

substantially impact their migratory 

behavior (Malme et al., 1984; Malme 

and Miles 1985; Richardson et al., 

1995), and Yazvenko et al. (2007b) 

reported no apparent changes in the 

frequency of feeding activity in Western 

gray whales exposed to airgun sounds in 

their feeding grounds near Sakhalin 

Island. Goldbogen et al. (2013) found 

29130 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

blue whales feeding on highly 

concentrated prey in shallow depths 

(such as the conditions expected within 

humpback feeding BIAs) were less 

likely to respond and cease foraging 

than whales feeding on deep, dispersed 

prey when exposed to simulated sonar 

sources, suggesting that the benefits of 

feeding for humpbacks foraging on highdensity prey may outweigh perceived 

harm from the acoustic stimulus, such 

as the seismic survey (Southall et al., 

2016). Additionally, L–DEO must shut 

down the airgun array upon observation 

of an aggregation of six or more large 

whales, which would reduce impacts to 

cooperatively foraging animals. For all 

habitats, no physical impacts to BIA 

habitat are anticipated from seismic 

activities. While SPLs of sufficient 

strength have been known to cause 

injury to fish and fish and invertebrate 

mortality, in feeding habitats, the most 

likely impact to prey species from 

survey activities would be temporary 

avoidance of the affected area and any 

injury or mortality of prey species 

would be localized around the survey 

and not of a degree that would adversely 

impact marine mammal foraging. The 

duration of fish avoidance of a given 

area after survey effort stops is 

unknown, but a rapid return to normal 

recruitment, distribution and behavior 

is expected. Given the short operational 

seismic time near or traversing BIAs, as 

well as the ability of cetaceans and prey 

species to move away from acoustic 

sources, NMFS expects that there would 

be, at worst, minimal impacts to animals 

and habitat within the designated BIAs. 

Critical habitat has been established 

on the U.S. West Coast for the eastern 

DPS of Steller sea lions (58 FR 45269; 

August 27, 1993) and in inland waters 

of Washington for Southern Resident 

killer whales (71 FR 69054; November 

29, 2006). Critical habitat for the Mexico 

and Central America DPSs of humpback 

whales has been established along the 

U.S. West Coast (86 FR 21082; April 21, 

2021), and NMFS has proposed 

expanding Southern Resident killer 

whale critical habitat to include coastal 

waters of Washington, Oregon, and 

California (84 FR 49214; September 19, 

2019). Only a small portion of L–DEO’s 

seismic survey will occur in or near 

these established or proposed critical 

habitats. 

Critical habitat for Steller sea lions 

has been established at two rookeries on 

the Oregon coast, at Rogue Reef 

(Pyramid Rock) and Orford Reef (Long 

Brown Rock and Seal Rock). The critical 

habitat area includes aquatic zones that 

extend 0.9 km seaward and air zones 

extending 0.9 km above these rookeries 

(NMFS 1993). Steller sea lions occupy 

rookeries and pup from late-May 

through early-July (NMFS 2008), which 

coincides with L–DEO’s survey. The 

Orford Reef and Rogue Reef critical 

habitats are located 7 km and 9 km from 

the nearest planned seismic transect 

line, respectively. Impacts to Steller sea 

lions within these areas, and throughout 

the survey area, are expected to be 

limited to short-term behavioral 

disturbance, with no lasting biological 

consequences. 

Critical habitat for the threatened 

Mexico DPS and endangered Central 

America DPS humpback whales has 

been established along the U.S. West 

Coast (86 FR 21082; April 21, 2021). The 

critical habitat encompasses the 

humpback whale feeding BIAs 

described above and generally includes 

waters between the 50-m isobath and 

the 1,200-m isobath, though some areas 

extend further offshore. NMFS 

determined that prey within humpback 

whale feeding areas are essential to the 

conservation of each of the three DPSs 

of humpback whales for which critical 

habitat was established (Mexico, Central 

America, and Western North Pacific 

DPSs). Critical habitat was therefore 

designated in consideration of 

importance that the whales not only 

have reliable access to prey within their 

feeding areas, but that prey are of a 

sufficient density to support feeding and 

the build-up of energy reserves. 

Although humpback whales are 

generalist predators and prey 

availability can very seasonally and 

spatially, substantial data indicate that 

the humpback whales’ diet is 

consistently dominated by euphausiid 

species (of genus Euphausia, 

Thysanoessa, Nyctiphanes, and 

Nematoscelis) and small pelagic fishes, 

such as northern anchovy (Engraulis 

mordax), Pacific herring (Clupea 

pallasii), Pacific sardine (Sardinops 

sagax), and capelin (Mallotus villosus) 

(Nemoto 1957, 1959; Klumov 1963; Rice 

Krieger and Wing 1984; Baker 1985; 

Kieckhefer 1992; Clapham et al., 1997; 

Neilson et al., 2015). While there are 

possible impacts of seismic activity on 

plankton and fish species (e.g., 

McCauley et al., 2017; Hastings and 

Popper 2005), the areas expected to be 

affected by L–DEO’s activities are small 

relative to the greater habitat areas 

available. Additionally, humpback 

whales feeding on high-density prey 

may be less likely to cease foraging 

when the benefit of energy intake 

outweighs the perceived harm from 

acoustic stimulus (Southall et al., 2016). 

Therefore, this seismic activity is not 

expected to have a lasting physical 

impact on humpback whale critical 

habitat, prey within it, or overall 

humpback whale fitness. Any impact 

would be a temporary increase in sound 

levels when the survey is occurring in 

or near the critical habitat and resulting 

temporary avoidance of prey or marine 

mammals themselves due these elevated 

sound levels. As stated above, L–DEO 

must shut down the airgun array upon 

observation of an aggregation of six or 

more large whales, which would reduce 

direct impacts to groups of humpback 

whales that may be cooperatively 

feeding in the area. 

As discussed earlier, in response to 

comments from the ENGOs, we 

acknowledge ongoing concern over the 

health and growth of the California/ 

Oregon/Washington stock of humpback 

whales, due to vessel strikes and other 

factors. As described above, though, 

impacts from this seismic survey are not 

expected to impact the fitness of any 

individuals and thereby will not alone, 

or incrementally in combination with 

other baseline stressors, adversely affect 

the stock through impacts on rates of 

recruitment or survival. 

Southern Resident Killer Whales 

In acknowledgment of our concern 

regarding the status of Southern 

Resident killer whales, including low 

abundance and a decreasing trend, we 

address impacts to this stock separately 

in this section. 

L–DEO’s planned tracklines do not 

overlap with existing Southern Resident 

killer whale habitat, but NMFS has 

proposed expanding Southern Resident 

critical habitat to include waters 

between the 6.1-m and 200-m depth 

contours from the U.S. international 

border with Canada south to Point Sur, 

California (84 FR 49214; September 19, 

2019). The proposed expanded critical 

habitat areas were identified in 

consideration of physical and biological 

features essential to conservation of 

Southern Resident killer whales 

(essential features): (1) Water quality to 

support growth and development; (2) 

Prey species of sufficient quantity, 

quality, and availability to support 

individual growth, reproduction, and 

development, as well as overall 

population growth; and (3) Passage 

conditions to allow for migration, 

resting, and foraging. NMFS did not 

identify in-water sound levels as a 

separate essential feature of existing or 

proposed expanded critical habitat 

areas, though anthropogenic sound is 

recognized as one of the primary threats 

to Southern Resident killer whales 

(NMFS 2019). Exposure to vessel noise 

and presence of whale watching boats 

can significantly affect the foraging 

behavior of Southern Resident killer 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29131 

whales (Williams et al., 2006; Lusseau et 

al., 2009; Giles and Cendak 2010; 

Senigaglia et al., 2016). Nutritional 

stress has also been identified as a 

primary cause of Southern Resident 

killer whale decline (Ayres et al., 2012; 

Wasser et al., 2017), suggesting that 

reduced foraging effort may have a 

greater impact than behavioral 

disturbance alone. However, these 

studies have primarily focused on 

effects of whale watch vessels operating 

in close proximity to Southern Resident 

killer whales, and commercial shipping 

traffic in the Salish Sea (i.e., the inland 

waters of Washington and British 

Columbia). Commercial whale watch 

and private recreational vessels 

operating in the waters around the San 

Juan Islands in summer months number 

in the dozens (Erbe 2002), and at least 

400 piloted vessels (commercial vessels 

over 350 gross tons and pleasure craft 

over 500 gross tons that are required to 

be guided in and out of the Port of 

Vancouver by British Columbia Coast 

Pilots) transit through Haro Strait each 

month (Joy et al., 2002). Concentration 

of vessel traffic on the outer coast, 

where the survey area occurs, is much 

lower than in the inland waters 

(Cominelli et al., 2018), suggesting that 

effects from vessel noise may be lower 

than in inland waters. Increased noise 

levels from the survey in any specific 

area would be short-term due to the 

mobile nature of the survey, unlike the 

near-constant vessel presence in inland 

waters. 

Approximately 30 percent of L–DEO’s 

total tracklines occur within the 200-m 

isobath along the coast of Oregon, 

Washington, and British Columbia. L– 

DEO is required to shut down seismic 

airguns immediately upon visual 

observation or acoustic detection of 

killer whales of any ecotype at any 

distance to minimize potential 

exposures of Southern Resident killer 

whales, and must operate within the 

200-m isobath in daylight hours only, to 

increase the ability to visually detect 

killer whales and implement 

shutdowns. Southern Resident killer 

whales exposed to elevated sound levels 

from the R/V Langseth and the airgun 

array may reduce foraging time, but no 

survey tracklines or ensonified area 

overlap with the areas of highest 

estimated densities of Southern 

Resident killer whales (see Table 9 of 

this notice and Figures 7–9 and 7–11 in 

the U.S. Navy’s MSDD (U.S. Navy 

2019)). While Southern Resident killer 

whales may be encountered outside of 

these areas of highest density, the 

likelihood is significantly decreased and 

the relatively small amount of time of 

altered behavior would not likely affect 

their overall foraging ability. Short-term 

impacts to foraging ability are not likely 

to result in significant or lasting 

consequences for individual Southern 

Resident killer whales or the population 

as a whole (Ayres et al., 2012). Due to 

the mobile nature of the survey, animals 

would not be exposed to elevated 

sounds for an extended period, and the 

proposed critical habitat contains a large 

area of suitable habitat that would allow 

Southern Resident killer whales to 

forage away from the survey. Noren et 

al. (2016) reported that although 

resident killer whales increase energy 

expenditure in response to vessel 

presence, the increase is considered to 

be negligible. 

No permanent hearing impairment 

(Level A harassment) is anticipated or 

authorized. Authorized takes of 

Southern Resident killer whales would 

be limited to Level B harassment in the 

form of behavioral disturbance. We 

anticipate 11 instances of Level B 

harassment of Southern Resident killer 

whales (10 takes by Level B harassment 

authorized in this IHA and one take by 

Level B harassment within Canadian 

territorial waters), which we expect 

would likely occur to a smaller subset 

of the population on only a few days. 

Limited, short term behavioral 

disturbance of the nature expected here 

would not be expected to result in 

fitness-level effects to individual 

Southern Resident killer whales or the 

population as a whole. 

Negligible Impact Conclusions 

The survey will be of short duration 

(37 days of seismic operations), and the 

acoustic ‘‘footprint’’ of the survey is 

small relative to the ranges of the 

marine mammals that will potentially 

be affected. Sound levels will increase 

in the marine environment in a 

relatively small area surrounding the 

vessel compared to the range of the 

marine mammals within the survey 

area. Short term exposures to survey 

operations are not likely to significantly 

disrupt marine mammal behavior, and 

the potential for longer-term avoidance 

of important areas is limited. 

The prescribed mitigation measures 

are expected to reduce the number and/ 

or severity of takes by allowing for 

detection of marine mammals in the 

vicinity of the vessel by visual and 

acoustic observers, and by minimizing 

the severity of any potential exposures 

via shutdowns of the airgun array. 

Based on previous monitoring reports 

for substantially similar activities that 

have been previously authorized by 

NMFS, we expect that the required 

mitigation will be effective in 

preventing, at least to some extent, 

potential PTS in marine mammals that 

may otherwise occur in the absence of 

the mitigation (although all authorized 

PTS has been accounted for in this 

analysis). Further, for Southern Resident 

Killer Whales (as described above), 

additional mitigation (e.g., second 

monitoring vessel, daylight only 

surveys) is expected to increase the 

ability of PSOs to detect killer whales 

and shut down the airgun array to 

reduce the instances and severity of 

behavioral disturbance. 

While operating within the Canadian 

EEZ, L–DEO will implement certain 

measures prescribed by Canada’s DFO 

that are more protective than those 

prescribed by NMFS under the MMPA. 

These include a requirement to avoid 

operating within or nearby designated 

Southern Resident or Northern Resident 

killer whale critical habitat such that the 

ensonified area above the 160 dB rms 

threshold does not extend inside critical 

habitat, shutting down the airgun array 

if a sperm whale or a beaked whale (any 

species) is observed within 1,500 m, and 

shutting down the airgun array if any 

species of marine mammal is observed 

within 1,000 m of the array. 

Additionally, throughout the entire 

survey area within the Canadian EEZ, 

L–DEO will not conduct survey 

operations in waters 100 m or less and 

will conduct seismic surveys in waters 

100 to 200 m deep during daylight 

hours only, with a second vessel having 

two marine mammal observers on 

watch, positioned 5 km ahead of the R/ 

V Langseth. L–DEO must also combine 

enhanced visual observations (e.g., 

reticle and big-eye binoculars, night 

vision devices and digital cameras) with 

non-visual detection methods (e.g., 

infrared technology (FLIR) and PAM) to 

increase the likelihood of detecting 

marine mammals during ramp up, 

Beaufort sea states >3, and night time 

survey operations. Finally, L–DEO must 

monitor the established exclusion zone 

with a radius of 1,000 m for 60 minutes 

prior to initial start-up of the airgun 

array or resumption of operations 

following a complete shutdown to allow 

for the detection of deep diving animals. 

NMFS concludes that exposures to 

marine mammal species and stocks due 

to L–DEO’s planned survey will result 

in only short-term (temporary and short 

in duration) effects to individuals 

exposed, over relatively small areas of 

the affected animals’ ranges. Animals 

may temporarily avoid the immediate 

area, but are not expected to 

permanently abandon the area. Major 

shifts in habitat use, distribution, or 

foraging success are not expected. 

NMFS does not anticipate the 

29132 Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 

authorized take to impact annual rates 

of recruitment or survival. 

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 serious injury or mortality is 

anticipated or authorized; 

• The planned activity is temporary 

and of relatively short duration (37 

days); 

• The anticipated impacts of the 

activity on marine mammals will 

primarily be temporary behavioral 

changes due to avoidance of the area 

around the survey vessel; 

• The number of instances of 

potential PTS that may occur are 

expected to be very small in number. 

Instances of potential PTS that are 

incurred in marine mammals are 

expected to be of a low level, due to 

constant movement of the vessel and of 

the marine mammals in the area, and 

the nature of the survey design (not 

concentrated in areas of high marine 

mammal concentration); 

• The availability of alternate areas of 

similar habitat value for marine 

mammals to temporarily vacate the 

survey area during the planned survey 

to avoid exposure to sounds from the 

activity; 

• The potential adverse effects on fish 

or invertebrate species that serve as prey 

species for marine mammals from the 

survey will be temporary and spatially 

limited, and impacts to marine mammal 

foraging will be minimal; and 

• The mitigation requirements, 

including visual and acoustic 

monitoring, shutdowns, and enhanced 

measures for areas of biological 

importance (e.g., additional monitoring 

vessel, daylight operations only) are 

expected to minimize potential impacts 

to marine mammals (both amount and 

severity). 

• Additionally as described above for 

Southern Resident killer whales 

specifically, anticipated impacts are 

limited to few days of behavioral 

disturbance for any one individual and 

additional mitigation (e.g., additional 

monitoring vessel, survey timing, 

shutdowns) are expected to ensure that 

both the numbers and severity of 

impacts to this stock are minimized, 

and, therefore the authorization of 

Southern Resident killer whale take is 

not expected to impact the fitness of any 

individuals, much less rates of 

recruitment or survival. 

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 

prescribed mitigation and monitoring 

measures, NMFS finds that the total 

marine mammal take from the planned 

activity will have a negligible impact on 

all affected marine mammal species or 

stocks. 

Small Numbers 

As noted above, only small numbers 

of incidental take may be authorized 

under Sections 101(a)(5)(A) and (D) of 

the MMPA for specified activities other 

than military readiness activities. The 

MMPA does not define small numbers 

and so, in practice, where estimated 

numbers are available, NMFS compares 

the number of individuals taken to the 

most appropriate estimation of 

abundance of the relevant species or 

stock in our determination of whether 

an authorization is limited to small 

numbers of marine mammals. 

Additionally, other qualitative factors 

may be considered in the analysis, such 

as the temporal or spatial scale of the 

activities. 

There are two stocks for which the 

estimated instances of take appear high 

when compared to the stock abundance 

(Table 10)—the California/Oregon/ 

Washington Dall’s porpoise stock and 

the Northern Oregon/Washington Coast 

harbor porpoise stock. However, when 

other qualitative factors are used to 

inform an assessment of the likely 

number of individual marine mammals 

taken, the resulting numbers are 

appropriately considered small. We 

discuss these in further detail below. 

For all other stocks (aside from the 

two referenced above and described 

below), the authorized take is less than 

one-third of the best available stock 

abundance (recognizing that some of 

those takes may be repeats of the same 

individual, thus rendering the actual 

percentage even lower). Additionally, 

we note that the authorized take is 

compared to the stock abundance for 

MMPA designated stocks, which for 

many species are limited to U.S. waters 

and do not include animals within the 

Canadian EEZ. Therefore, for species 

with transboundary populations, the 

actual percentage of the population 

affected is lower than that shown in 

Table 10. 

The expected take of the California/ 

Oregon/Washington stock of Dall’s 

porpoises, as a proportion of the 

population abundance, is 36.94 percent, 

if all takes are assumed to occur for 

unique individuals. In reality, it is 

unlikely that all takes would occur to 

different individuals. L–DEO’s survey 

area represents a small portion of the 

stock’s overall range (Caretta et al., 

2017), and it is more likely that there 

will be multiple takes of a smaller 

number of individuals within the action 

area. In addition, Best et al. (2015) 

estimated the population of Dall’s 

porpoise in British Columbia to be 5,303 

porpoises based on systematic linetransect surveys of the Strait of Georgia, 

Johnstone Strait, Queen Charlotte 

Sound, Hecate Strait, and Dixon 

Entrance between 2004 and 2007. In 

consideration of the greater abundance 

estimate combining the U.S. stock and 

animals in British Columbia, and the 

likelihood of repeated takes of 

individuals, it is unlikely that more than 

one-third of the stock will be exposed to 

the seismic survey. 

When assuming all estimated takes of 

harbor porpoise (8,241 total takes by 

Level A and B harassment) will occur to 

the Northern Oregon/Washington Coast 

stock, the take appears high relative to 

stock abundance (38.35 percent). In 

reality, takes will occur to both the 

Northern Oregon/Washington Coast and 

Northern California/Southern Oregon 

stocks, and therefore, the number of 

takes of each stock will be much lower. 

NMFS has no commonly used method 

to estimate the relative proportion of 

each stock that will experience take, but 

here we propose to apportion the takes 

between the two stocks based on the 

stock boundary (Lincoln City, Oregon) 

and the approximate proportion of the 

survey area that will occur on either 

side of the stock boundary. North of 

Lincoln City, Oregon, harbor porpoises 

belong to the Northern Oregon/ 

Washington Coast stock, and south of 

Lincoln City, harbor porpoises belong to 

the Northern California/Southern 

Oregon stock. Approximately one-third 

of the planned survey occurs south of 

Lincoln City, therefore one-third of the 

total estimated takes are assumed to be 

from the Northern California/Southern 

Oregon stock. The remaining two-thirds 

of the estimated takes are assumed to be 

from the Northern Oregon/Washington 

Coast stock. The estimated one-third of 

total takes assigned to the Northern 

California/Southern Oregon stock (2,747 

total Level A and Level B takes) 

represent 7.68 percent of the stock 

abundance, which NMFS considers to 

be small relative to the stock abundance. 

In addition, the survey area represents 

a small portion of the stock’s range, and 

it is likely that there will be multiple 

takes of a small portion of individuals, 

further reducing the number of 

individuals exposed. The estimated 

two-thirds of total takes assigned to the 

Northern Oregon/Washington Coast 

stock (5,494 takes) represent 25.57 

percent of the stock abundance, which 

Federal Register / Vol. 86, No. 102 / Friday, May 28, 2021 / Notices 29133 

NMFS considers to be small relative to 

the stock abundance. Additionally, the 

Northern Oregon/Washington Coast 

stock abundance estimate does not 

include animals in Canadian waters 

(Caretta et al., 2017). Best et al. (2015) 

estimated a population abundance of 

8,091 harbor porpoises in British 

Columbia. The estimated takes of 

animals in the northern portion of the 

survey area (north of Lincoln City) 

represent 18.57 percent of the combined 

British Columbia and Northern Oregon/ 

Washington Coast abundance estimates, 

which NMFS considers to be small 

relative to the stock abundance. 

Based on the analysis contained 

herein of the planned activity (including 

the required mitigation and monitoring 

measures) and the anticipated take of 

marine mammals, NMFS finds that 

small numbers of marine mammals will 

be taken relative to the population size 

of the affected species or stocks. 

Unmitigable Adverse Impact Analysis 

and Determination 

There are no relevant subsistence uses 

of the affected marine mammal stocks or 

species implicated by this action. 

Therefore, NMFS has determined that 

the total taking of affected species or 

stocks will not have an unmitigable 

adverse impact on the availability of 

such species or stocks for taking for 

subsistence purposes. 

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 

incidental harassment authorization) 

with respect to potential impacts on the 

human environment. 

Accordingly, NMFS has adopted the 

NSF’s EA, as we have determined that 

it includes adequate information 

analyzing the effects on the human 

environment of issuing the IHA, and 

prepared a FONSI. NSF’s EA is available 

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

envcomp/, and NMFS’ FONSI is 

available at https://www.fisheries.

noaa.gov/national/marine-mammalprotection/incidental-takeauthorizations-research-and-otheractivities. 

Endangered Species Act (ESA) 

Section 7(a)(2) of the Endangered 

Species Act of 1973 (ESA: 16 U.S.C. 

1531 et seq.) requires that each Federal 

agency insure that any action it 

authorizes, funds, or carries out is not 

likely to jeopardize the continued 

existence of any endangered or 

threatened species or result in the 

destruction or adverse modification of 

designated critical habitat. To ensure 

ESA compliance for the issuance of 

IHAs, NMFS consults internally 

whenever we propose to authorize take 

for endangered or threatened species. 

The NMFS Office of Protected 

Resources ESA Interagency Cooperation 

Division issued a Biological Opinion 

under section 7 of the ESA, on the 

issuance of an IHA to L–DEO under 

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

NMFS OPR Permits and Conservation 

Division. The Biological Opinion 

concluded that the proposed action is 

not likely to jeopardize the continued 

existence of ESA-listed blue whales, fin 

whales, sei whales, sperm whales, 

Central America DPS humpback whales, 

Mexico DPS humpback whales, 

Southern Resident killer whale DPS, 

and Guadalupe fur seals, and is not 

likely to destroy or adversely modify 

designated Steller sea lion or humpback 

whale critical habitat. There is no 

designated critical habitat in the action 

area for the other ESA-listed species. 

Authorization 

As a result of these determinations, 

NMFS has issued an IHA to L–DEO for 

conducting a marine geophysical survey 

in the northeast Pacific Ocean beginning 

in June 2021, provided the previously 

mentioned mitigation, monitoring, and 

reporting requirements are incorporated. 

Dated: May 24, 2021. 

Catherine Marzin, 

Acting Director, Office of Protected Resources, 

National Marine Fisheries Service. 

[FR Doc. 2021–11375 Filed 5–27–21; 8:45 am] 

BILLING CODE 3510–22–P