Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to an Exploration Drilling Program in the Chukchi Sea, Alaska

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD655

Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to an Exploration Drilling Program in the Chukchi Sea, Alaska

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 Marine Mammal Protection Act (MMPA) regulations, notification is hereby given that NMFS has issued an Incidental Harassment Authorization (IHA) to Shell Gulf of Mexico Inc. (Shell) to take marine mammals, by harassment, incidental to offshore exploration drilling on Outer Continental Shelf (OCS) leases in the Chukchi Sea, Alaska.

DATES:

Effective July 1, 2015, through October 31, 2015.

ADDRESSES:

A copy of the issued IHA, application with associated materials, and NMFS' Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) may be obtained by writing to Jolie Harrison, Chief, Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910, telephoning the contact listed below (see

FOR FURTHER INFORMATION CONTACT

), or visiting the internet at:

http://www.nmfs.noaa.gov/pr/permits/incidental.htm.

Documents cited in this notice may also be viewed, by appointment, during regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT:

Shane Guan, Office of Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361

et seq.

) direct the Secretary of Commerce 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 authorization is provided to the public for review.

An authorization for incidental takings shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. NMFS has defined “negligible impact” in 50 CFR 216.103 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”.

Except with respect to certain activities not pertinent here, 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].

Summary of Request

On September 18, 2014, Shell submitted an application to NMFS for the taking of marine mammals incidental to exploration drilling activities in the Chukchi Sea, Alaska. After receiving comments and questions from NMFS, Shell revised its IHA application and related Marine Mammal Mitigation and Monitoring Plan (4MP) on December 17, 2014. NMFS determined that the application was adequate and complete on January 5, 2015.

NMFS published a Notice of Proposed IHA in the

Federal Register

on March 4, 2015 (80 FR 11726). That notice contained in-depth descriptions and analyses that may be summarized but are generally not repeated in this document. Only in cases where descriptions or analyses changed is that information updated here.

The proposed activity would occur between July and October 2015. The following specific aspects of the proposed activities are likely to result in the take of marine mammals: Exploration drilling, supply and drilling support vessels using dynamic positioning, mudline cellar construction, anchor handling, ice management activities, and zero-offset vertical seismic profiling (ZVSP) activities.

Shell requested an authorization to take 13 marine mammal species by Level B harassment. However, the narwhal (

Monodon monoceros

) is not expected to be found in the activity area. Therefore, NMFS proposed to authorize take of 12 marine mammal species, by Level B harassment, incidental to Shell's offshore exploration drilling in the Chukchi Sea. These species are: Beluga whale (

Delphinapterus leucas

); bowhead whale (

Balaena mysticetus

); gray whale (

Eschrichtius robustus

); killer whale (

Orcinus orca

); minke whale (

Balaenoptera acutorostrata

); fin whale (

Balaenoptera physalus

); humpback whale (

Megaptera novaeangliae

); harbor porpoise (

Phocoena phocoena

); bearded seal (

Erignathus barbatus

); ringed seal (

Phoca hispida

); spotted seal (

P. largha

); and ribbon seal (

Histriophoca fasciata

).

In 2012, NMFS issued two IHAs to Shell to conduct two exploratory drilling activities at exploration wells in the Beaufort (77 FR 27284; May 9, 2012) and Chukchi (77 FR 27322; May 9, 2012) Seas, Alaska, during the 2012 Arctic open-water season (July through October). Shell's proposed 2015 exploration drilling program is similar though not identical to those conducted in 2012. (In December 2012, Shell submitted two additional IHA applications to take marine mammals incidental to its proposed exploratory drilling in Beaufort and Chukchi Seas during the 2013 open-water season. However, Shell withdrew its application in February 2013).

Description of the Specified Activity

Overview

Shell proposes to conduct exploration drilling at up to four exploration drill sites at Shell's Burger Prospect on the OCS leases acquired from the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM). The exploration drilling planned for the 2015 season is a continuation of the Chukchi Sea exploration drilling program that began in 2012, and resulted in the completion of a partial well at the location known as Burger A.

Shell plans to use two drilling units, the drillship

Noble Discoverer

(

Discoverer

) and semi-submersible

Transocean Polar Pioneer

(

Polar Pioneer

) to drill at up to four locations on the Burger Prospect. Both drilling units will be attended to by support vessels for the purposes of ice management, anchor handling, oil spill response (OSR), refueling, support to drilling units, and resupply. The

drilling units will be accompanied by a greater number of support vessels, aircraft, and oil spill response vessels (OSRV) greater than the number deployed during the 2012 drilling season.

Dates and Duration

Shell anticipates that its exploration drilling program will occur between July 1 and approximately October 31, 2015. The drilling units will move through the Bering Strait and into the Chukchi Sea on or after July 1, 2015, and then onto the Burger Prospect as soon as ice and weather conditions allow. Exploration drilling activities will continue until about October 31, 2015, and the drilling units and support vessels will exit the Chukchi Sea at the conclusion of the exploration drilling season.

Specified Geographic Region

All drill sites at which exploration drilling would occur in 2015 will be at Shell's Burger Prospect (see Figure 1-1 on page 1-2 of Shell's IHA application). Shell has identified a total of six Chukchi Sea lease blocks on the Burger Prospect. All six drill sites are located more than 64 mi (103 km) off the Chukchi Sea coast. During 2015, the

Discoverer

and

Polar Pioneer

will be used to conduct exploration drilling activities at up to four of the six exploration drill sites (up to two at a time). As with any Arctic exploration program, weather and ice conditions will dictate actual operations.

Detailed Description of Activities

The Notice of Proposed IHA (80 FR 11726; March 4, 2015) contained a full description of Shell's planned operations. That notice describes the equipment to be used for the different operational activities, the timeframe of activities, and the sound characteristics of the associated equipment. There is no change to Shell's planned exploration drilling activity, therefore, the information is not repeated here. Please refer to the proposed IHA notice for the full description of the specified activity.

Comments and Responses

A Notice of Proposed IHA published in the

Federal Register

on March 4, 2015 (80 FR 11726) for public comment. During the 30-day public comment period, NMFS received 8 comment letters from the following: The Marine Mammal Commission (Commission); the Alaska Eskimo Whaling Commission (AEWC); the North Slope Borough (NSB); Shell; the Northern Alaska Environment Center (NAEC); the Environmental Investigation Agency (EIA); Oceana, Ocean Conservancy, and Audubon Alaska (collectively Oceana); and Alaska Wilderness League (AWL), Center for Biological Diversity, Earthjustice, EIA, Greenpeace, Natural Resources Defense Council, NAEC, Ocean Conservation Research, and Sierra Club (collectively “AWL”), along with a form letter signed by 180,036 private citizens (with many duplicate submissions).

All of the public comment letters received on the Notice of Proposed IHA (80 FR 11726; March 4, 2015) are available on the internet at:

http://www.nmfs.noaa.gov/pr/permits/incidental.htm.

Following are the public comments and NMFS' responses.

General Comments

Comment 1:

The Commission notes that NMFS does not typically authorize the taking of marine mammals incidental to mudline construction and anchor handling. The Commission further recommends that if NMFS intends to authorize the taking of marine mammals incidental to these types of activities, NMFS should provide guidance and follow a consistent approach in assessing the potential for taking by Level B harassment, including whether applicants should include requests for authorizations of such taking in their applications.

Response:

NMFS has not authorized marine mammal takes by Level B harassment that result from mudline cellar construction and anchor handling because there had been no documentation that noises generated from such activities were significant enough to cause take. The noise levels of these activities were first measured during the sound source verification tests for Shell's exploration drilling activities in the Beaufort and Chukchi seas in 2012, and were reported in the 90-day reports of these activities. As detailed in the notice for the proposed IHA (80 FR 11726; March 4, 2015), the Level B harassment radii (120-dB isopleths) for mudline cellar construction and anchor handling are 8.2 and 19 km from the sources, respectively.

For determining whether impacts from sound-generating activities rise to Level B harassment of marine mammals, NMFS' current guidance is that if an animal is exposed to received noise levels higher than 160-dB for impulse source or 120-dB for non-impulse source, then it is considered a take. In the case of mudline cellar construction and anchor handling, NMFS required sound source verification (SSV) tests on these sources in the 2012 IHAs issued to Shell for its 2012 open-water exploration drilling activities. The results showed that these activities generate significant underwater noise that could result in take under NMFS' current guidance for marine mammal behavioral harassment, and NMFS considers that takes are likely from these activities for Shell's 2015 exploration drilling activity in the Chukchi Sea. As a result, impacts from these sound sources should be considered in future incidental take applications and analyses.

Comment 2:

The NSB requests an extension of the 30-day comment period for the proposed IHA. The NSB states that because Shell's Chukchi Sea Exploration Plan is incredibly detailed, yet has not yet been “deemed submitted” by the Bureau of Ocean Energy Management (BOEM), the NSB has not had the opportunity to review all the details. In addition, the NSB states that having two drill rigs operating near one another could cause major impacts, and that without evaluating the entire Exploration Plan, the NSB cannot fully evaluate how all aspects of the operation will move forward, nor can the NSB evaluate the cumulative impacts on marine mammals.

Response:

NMFS received the NSB's request on April 3, 2015, the last day of the comment period for the proposed IHA. As a practical matter an extension of the public comment period would not have been possible given the short time period left to consider the request. Section 101(a)(5)(D) of the MMPA was intended to provide a mechanism for more expedited review and issuance of marine mammal incidental take authorizations (than section 101(a)(5)(A)), assuming the required findings can be made. We complied with the 30-day public comment period specified in the statute. In this case, an extension of or an additional comment period could have delayed issuance of the IHA in the timeframe requested by Shell for it to conduct its specified activity.

Although Shell's Exploration Plan was not “deemed submitted” by BOEM until after the closing of NMFS' public comment period, we note that a second draft “Revision 2” of Shell's Chukchi Sea Exploration Plan was submitted to BOEM and publicly available since August 2014. See

http://www.boem.gov/shell-chukchi/.

Further, the information provided to NMFS in Shell's IHA application and marine mammal mitigation and monitoring plan (4MP) contained substantial information for NMFS to analyze potential impacts to marine mammals from Shell's proposed

exploration drilling. Information provided by Shell to NMFS for impact analysis included a detailed description of the acoustic footprint from two drill rigs operating near one another, and total ensonified area resulting from two different sources. Therefore, adequate information was publicly available to evaluate potential impacts to marine mammals from Shell's proposed exploration drilling activities in the Chukchi during the 2015 Arctic open-water season even before the Exploration Plan was officially deemed submitted.

Comment 3:

The NSB noted that NMFS convened an independent peer review panel to review Shell's 4MP for the proposed exploration drilling in the Chukchi Sea, and that after the review process NMFS will consider all recommendations made by the panel and incorporate appropriate changes in the monitoring requirements of the IHA (if issued). The NSB states that it would be useful to the NSB to have the benefit of this feedback and proposed changes when evaluating the IHA.

Response:

In evaluating potential marine mammal impacts from Shell's proposed exploration drilling program in the Chukchi Sea, NMFS published a

Federal Register

notice of proposed IHA for public comment. The

Federal Register

notice contains substantial information on Shell's proposed activities, potential impacts to marine mammals and subsistence harvest, and proposed mitigation, monitoring, and reporting measures. In addition, Shell's IHA application and 4MP are posted on NMFS' Web site along with the

Federal Register

for public examination and comments. Furthermore, the peer-review panel report on Shell's 4MP, along with the panel's recommendations, as well as changes made by NMFS to the monitoring and reporting measures, are available to the public in this document and will be posted on NMFS' Web site. However, due to the short duration of the statutory timeframe of the IHA process (120 days), it was not possible to afford additional time for feedback on the peer-review panel reports and proposed changes. Nevertheless, NMFS believes that the IHA process allows NMFS to receive the benefit of important input from the public, subsistence users, and peer review in its decision making.

Impact Analysis

Comment 4:

Shell notes that the functional hearing frequency ranges provided in the

Federal Register

notice for the proposed IHA are inconsistent with those presented in Southall

et al.

(2007), specifically, the low frequency and pinniped hearing groups. Shell states that the extension of the hearing range of low-frequency cetaceans is not supported by empirical evidence. Shell argues that there is no evidence indicating that mysticetes hear above 20-22 kHz, and there are no empirical data to support expansion to 30 kHz. Shell also notes that these ranges appear to be drawn from NMFS' draft acoustic criteria, which are still under review and have not been finalized. Shell requests NMFS provide justification for the ranges listed above including associated references.

Response:

The hearing frequency ranges of functional hearing groups provided in the

Federal Register

notice is based on current data (via direct measurements [behavioral and electrophysiological]) and predictions (based on inner ear morphology, behavior, vocalizations, or taxonomy), which indicate that not all marine mammal individuals/species have equal hearing capabilities, in terms of absolute hearing sensitivity and the frequency band of hearing (Richardson

et al.

1995; Wartzok and Ketten 1999; Southall

et al.

2007; Au and Hastings 2008). Hearing has been directly measured in a multitude of odontocete and pinniped species (see review in Southall

et al.

2007). Direct measurements of mysticete hearing are lacking (

e.g.,

there was an unsuccessful attempt to directly measure hearing in a stranded gray whale calf by Ridgway and Carder 2001). Thus, scientifically based hearing predictions for mysticetes are based on other scientific methods (

e.g.,

anatomical studies: Houser

et al.

2001; Parks

et al.

2007; vocalizations: See reviews in Richardson

et al.

1995; Wartzok and Ketten 1999; Au and Hastings 2008; taxonomy and behavioral responses to sound: Dahlheim and Ljungblad 1990; see review in Reichmuth 2007).

To more accurately reflect marine mammal hearing capabilities, Southall

et al.

(2007) recommended that marine mammals be divided into functional hearing groups based on measured or estimated functional hearing ranges. Based on additional data, NOAA modified the functional hearing groups proposed by Southall

et al.

(2007) for species relevant to this action as follows:

•

Extension of upper end of low-frequency cetacean hearing range:

NOAA extended slightly the estimated upper end of the hearing range for low-frequency cetaceans, from 22 to 25 kHz, based on data from Watkins

et al.

(1986) for numerous mysticete species (variety of mysticete species responding to sounds up to 28 kHz), Au

et al.

(2006) for humpback whales (songs having harmonics that extend beyond 24 kHz), Lucifredi and Stein (2007) for gray whales (reported potentially responding to sounds beyond 22 kHz), and an unpublished report (Ketten and Mountain 2009) and data (Tubelli

et al.

2012) for minke whales (predicted hearing range of up to 30 kHz based on inner ear anatomy). These new data indicate that at least some mysticete species can hear above 22 kHz. Thus our current understanding of low-frequency cetaceans' hearing range is 7 Hz-25 kHz. As more data become available, these estimated hearing ranges may require future modification.

•

Division of pinnipeds into phocids and otariids:

NOAA subdivided pinnipeds into their two families: Phocidae and Otariidae. Based on a review of the literature, phocid species have consistently demonstrated an extended frequency range of hearing compared to otariids, especially in the higher frequency range (Hemilä

et al.

2006; Kastelein

et al.

2009; Reichmuth

et al.

2013). This is believed to be because phocid ears are anatomically distinct from otariid ears in that phocids have larger, more dense middle ear ossicles, inflated auditory bulla, and larger portions of the inner ear (

i.e.,

tympanic membrane, oval window, and round window), which make them more adapted for underwater hearing (Terhune and Ronald 1975; Kastak and Schusterman 1998; Hemilä

et al.

2006; Mulsow

et al.

2011; Reichmuth

et al.

2013).

NMFS considers this classification reflects the incorporation of the best scientific information since Southall

et al.

2007, and is considered in our effects analyses for marine mammal incidental take authorizations.

Comment 5:

The Commission noted that when estimating the number of bowhead takes, Shell assumed that 50 percent of all bowheads would avoid the Level B harassment zone during exploratory drilling and related support activities. The Commission generally does not agree with using assumptions of marine mammal avoidance of certain activities when estimating takes, unless the studies supporting such assumptions were based on the same or very similar circumstances and NMFS has determined that such avoidance would not result in an abandonment or significant alteration of behavioral patterns. The Commission further states that if NMFS intends to adjust take estimates based on assumed levels of avoidance, the Commission recommends that NMFS should provide guidance and follow a consistent approach in the adjustment of those estimates.

Response:

NMFS agrees with the Commission that general avoidance by marine mammals of an ensonified area is a form of Level B harassment. Therefore, NMFS worked with Shell and revised the bowhead whale take analysis, which is provided in details below. While we agree that avoidance

occurs, the revised take estimate of bowhead whales assumes that the animals that avoid the area will be taken by Level B harassment. In short, the 50% adjustment to Level B take numbers for avoidance is no longer applied.

Separately, however, NMFS also recognizes that the approach used here, which includes consideration of the number of days, results in an overestimate of takes, because it assumes a 24-hour turnover rate of bowhead whales in the ensonified area. This is not likely due to the large area of the Level B harassment zone (modelled at 22 km radius for anchor handling) and the slow migration speed of bowhead whales (Mate

et al.

2000) and observed feeding behavior in the area. Tagging studies showed that bowhead whales moved at speeds between 1.1 and 5.8 km/h, with frequent stay at places to feed (Mocklin 2009). Although a precise quantitative assessment of the turnover rate is difficult due to large variation among individual whales, NMFS considers it reasonable yet conservative to assume an averaged 48-hour turnover rate for bowheads in the ensonified area when estimating bowhead whales that could be taken by Level B harassment.

Comment 6:

Citing NMFS' impact analysis when issuing an IHA to Shell to take marine mammals incidental to exploratory drilling in the Beaufort Sea (77 FR 27284, 27288 [May 9, 2012]), Shell requests that NMFS continue to recognize the scientific evidence for avoidance of bowhead whales from drilling related activities, and not deviate from its prior position in 2012, which asserted that avoidance does not always rise to a level that constitutes a Level B take.

Response:

NMFS recognizes that some marine mammals will avoid drilling related activities to differing degrees. Further, there may be some small degree of avoidance that occurs at lower received levels that would not rise to the level of a take; however, avoidance that is expected, or modeled, within or near the 160-dB isopleth (where there are data illustrating notable avoidance responses (Richardson

et al.,

1995)) is considered behavioral harassment. Therefore, it is inappropriate to suggest that some portion of animals that would otherwise be expected to be exposed within the 160-dB isopleth be considered

not taken

because they would avoid the area—as the avoidance itself is a form of Level B harassment. Because Shell proposed to quantitatively adjust their estimated level B take numbers in their application, it was necessary for NMFS to further interpret this issue, however, we consider this a clarification rather than a deviation from what was included in the 2012 notice.

Comment 7:

NAEC, AWL, and a form letter from private citizens state that Shell's activities would harm more than small numbers of marine mammals or that the impacts will be more than negligible. EIA states that Shell's proposed ice management activities will expose an unacceptable number of belugas to harassing levels of noise.

Response:

NMFS is required to authorize the take of “small numbers” of a species or stock if the taking by harassment will have a negligible impact on the affected species or stocks and will not have an unmitigable adverse impact on the availability of such species or stock for taking for subsistence purposes. See 16 U.S.C. 1371(a)(5)(D). In determining whether to authorize “small numbers” of a species or stock, NMFS determines that the taking will be small relative to the estimated population size. With the exception of the ringed seal, less than 5.1% of each species stock or population would be taken by Level B harassment incidental to Shell's activities. The modeling results indicate that 8.4% of the ringed seal population would be taken by Level B harassment. For bowhead, gray, and beluga whales, NMFS further consulted with the National Marine Mammal Laboratory and NMFS Alaska Regional Office and revised the estimated takes using a more robust dataset. The results show that except for beluga whale, the estimated takes of bowhead and gray whales are further reduced to 5.5% and 4.4% of their population from the previous estimates of 13.2% and 13.5%, respectively. For beluga whales, the revised take estimate is 1,662 instead of 974 animals. Further breakdown of stock specific takes provide a result of 344 animals (9.3%) of the East Chukchi Sea stock and 1,318 animals (3.4%) of the Beaufort Sea stock. A detailed description of the take calculation on beluga whales is provided in section “

Estimated Takes”

below. We also note the following important factors:

(1) In all of the modeling submitted by Shell, a 1.3 dB safety factor was added to the source level of each continuous sound source prior to sound propagation modeling of areas exposed to Level B thresholds, which make the effective zones for take calculation larger than they likely will be;

(2) Shell applied binning of similar activity scenarios into a representative scenario, each of which reflected the largest exposed area for a related group of activities;

(3) Except for bowhead whale, the take estimates assume 100% daily turnover of population for all other species, which likely overestimates the number of different individuals that would be exposed, especially during non-migratory periods. Even for the bowhead whale, which is slow moving and often observed stopping to feed during its fall migration, a 50% daily (

i.e.,

48-hour) turnover of population was included in take calculation; and

(4) Density estimates for some cetaceans include nearshore areas, where more individuals would be expected to occur than in the offshore Burger Prospect area (

e.g.,

gray whales).

Based on this analysis, NMFS concluded that takes resulting from Shell's activities will constitute small numbers of marine mammals of the affected species or stocks.

In making a negligible impact determination, NMFS considers a variety of factors, including: (1) The number of anticipated mortalities; (2) the number and nature of anticipated injuries; (3) the number, nature, intensity, and duration of Level B harassment; and (4) the context in which the takes occur. NMFS has determined that Shell's activities will not result in injury or mortality of marine mammals. The proposed IHA notice analyzed the number, nature, intensity, and duration of the Level B harassment that may occur and the context in which it may occur. That analysis led us to make a negligible impact finding.

Comment 8:

NAEC states that the take thresholds NMFS uses are outdated.

Response: NMFS does not agree with NAEC's statement. NMFS uses 160 dB (rms) as the exposure level for estimating Level B harassment takes for impulse noise source and 120 dB (rms) for non-impulse noise source. These thresholds were established based on measured avoidance responses observed in whales in the wild. Specifically, the 160 dB threshold was derived from data for mother-calf pairs of migrating gray whales (Malme

et al.,

1983, 1984) and bowhead whales (Richardson

et al.,

1985, 1986) responding to seismic airguns (

e.g.,

impulsive sound source). While the 120 dB threshold is a more conservative threshold for non-impulse sources (

e.g.,

drilling) given that these sources have longer duration than impulsive noises and thus most likely longer than the integration time needed for acoustic detection by an animal.

We acknowledge there is more recent information bearing on behavioral reactions to seismic airguns, but those data only illustrate how complex and context-dependent the relationship is

between the two. See 75 FR 49710, 49716 (August 13, 2010) (IHA for Shell seismic survey in Alaska; response to comment 9). Accordingly, it is not a matter of merely replacing the existing threshold with a new one. NOAA is working to develop relatively more sophisticated draft guidelines for determining acoustic impacts, including information for determining Level B harassment thresholds. Due to the complexity of the task, the draft guidelines will undergo a rigorous review that includes internal agency review, public notice and comment, and external peer review before any final product is published. In the meantime, and taking into consideration the facts and available science, NMFS determined it is reasonable to use the 160 dB and 120 dB thresholds for estimating takes of marine mammals in the Chukchi Sea by Level B harassment. However, we discuss the science on this issue qualitatively in our analysis of potential effects to marine mammals.

Comment 9:

EIA states that Shell's application (1) relies on outdated beluga population data, (2) conflates resident and migratory populations, and (3) utilizes faulty beluga survey methods.

Response:

NMFS does not agree with EIA's statement. First, the beluga whale densities used to estimate potential exposure were calculated from aerial survey data collected by the National Marine Mammal Laboratory (NMML) from July through October of 2008-2014. These are the best scientific information available for the impact analysis. Second, there is no “resident” population of beluga whale in the Chukchi Sea as stated by the EIA's comment. When analyzing potential impacts to beluga whales that could result from Shell's proposed exploration drilling activity, we reviewed the available information on stock structure, migratory behavior, and density of the beluga whale Eastern Chukchi Sea Stock and the Beaufort Sea Stock in the Chukchi Sea and made judgments based on that information.

Comment 10:

EIA states that Shell's proposed noise mitigation measures fail to take into account the sensitivity of belugas to noise, particularly airgun-related noise. EIA further points out that in Shell's IHA application, belugas are not afforded the greater levels of mitigation that Shell's proposal gives larger whales. For example, upon sighting a beluga, airgun testing is not allowed to resume for 15 minutes, as opposed to the longer 30-minute pause for larger whales.

Response:

The apparent sensitivity of belugas to anthropogenic sounds in certain circumstances/locations means that beluga whales are unlikely to occur within the exclusion zone around an operating airgun. Nevertheless, to be consistent with other Arctic open-water activities for which NMFS issues take authorizations, NMFS changed the IHA to require that should a beluga occur within an exclusion zone during airgun operations, the longer 30-minute pause will be required if the animal is not sighted exiting the exclusion zone.

Comment 11:

The AWL states that there are large gaps in basic scientific information about both the Chukchi Sea ecosystem and marine mammal responses to noise, and that these gaps prevent adequate analysis of the potential impacts of Shell's proposed activities on wildlife.

Response:

As required by NMFS' MMPA implementing regulations at 50 CFR 216.102(a), NMFS has used the best scientific information available in assessing potential impacts and whether the activity will have a negligible impact on the affected marine mammal species or stock. While NMFS agrees that there may be some gaps in information about the Chukchi Sea ecosystem and in our understanding of how some taxa respond to noise in certain situations, at this point, results from many studies illustrate well the range of likely responses to industrial noise across a wide variety of species (Southall

et al.

2007; LGL

et al.

2014). Much of this work on the Arctic species addressed here has been conducted as part of the monitoring requirements of previous MMPA authorizations (

e.g.,

HDR 2013; Beland

et al.

2013; Reider

et al.

2013). In order to issue the IHA to Shell, NMFS conducted rigorous analyses using the best available scientific information about both the Chukchi Sea ecosystem and marine mammal responses to noise, and we are confident that the content of this extensive dataset supports our findings. These analyses are provided in the

Federal Register

notice (80 FR 11726; March 4, 2015) for the proposed IHA and EA prepared by NMFS.

Industrial activities have been occurring (at varying levels) in the U.S. Arctic Ocean for decades, and the available measurable indicators do not suggest that these activities are having long-term impacts on marine mammal species/stocks in the area. For example, bowhead whales continued to increase in abundance during periods of intense seismic activity in the Chukchi Sea in the 1980s (Raftery

et al.,

1995; Angliss and Outlaw, 2007), even without implementation of current mitigation requirements. This increase has been observed to continue to date (Givens

et al.

2013). Additionally, industry has been collecting data and conducting monitoring in the region for many years and will continue to do so under this IHA. Therefore, NMFS' negligible impact finding is supported by the available facts and science.

Comment 12:

The AWL states that NMFS uses outdated thresholds for acoustic impact analysis, and that the new criteria will likely increase the estimated number of bowhead whales, other cetaceans, and ice seals that could be disturbed by exploratory activities, and in some cases the increased level of disturbance could be large.

Response:

The AWL did not specify in its comment whether it was referring to Level A or Level B harassment thresholds. Nevertheless, NMFS does not agree with AWL's assessment. First, for Level A takes, NMFS' proposed draft guidance for acoustic injury criteria use a different set of metrics than the current criteria, meaning that one cannot simply compare 180 dB to the numbers proposed in the draft acoustic guidance. The proposed criteria have a duel metric of both peak pressure as sound pressure level (SPL) and sound exposure level (SEL), while the current acoustic criteria use root-mean-squared (RMS) as SPL. Additionally, the draft guidance for injury also include taxa-specific filters that must be applied in order to apply the new thresholds, making it even more difficult to compare directly to the current 180-dB threshold.

Second, Shell's proposed exploration drilling will result in Level B harassment takes only, and Level B behavioral harassment thresholds are not addressed in NMFS' draft acoustic threshold guidance. As indicated elsewhere in this

Federal Register

Notice, NMFS is working to develop guidance on updated behavioral take thresholds but NMFS believes the current thresholds are still appropriate. See response to Comment 8.

Comment 13:

AWL states that NMFS' uniform marine mammal harassment thresholds do not consider documented reactions of specific species in the Arctic to much lower received levels. The letter notes reactions of bowhead and gray whales to certain activities emitting impulse sounds below 160 dB and of beluga and bowhead whales and harbor porpoise reacting to other sound sources below 120 dB.

Response:

For non-impulse sounds, such as those produced by drilling operations and during icebreaking activities, NMFS uses a received level of 120-dB (rms) to indicate the onset of Level B harassment. For impulsive sounds, such as those produced by the airgun array during the ZVSP surveys,

NMFS uses a received level of 160-dB (rms) to indicate the onset of Level B harassment. Therefore, while a level of 160-dB was used to estimate take for a portion of the operations that will only occur for a total of 10-14 hours for each survey, depending on how many wells are drilled, during the entire 4-month open-water season, a threshold of 120-dB was used to estimate potential takes for all species from the drilling operations and ice management/icebreaking activities.

While some published articles indicate that certain marine mammal species may avoid seismic airguns (an impulsive sound source) at levels below 160 dB, when predicting take estimates for incidental take authorizations NMFS does not consider that these exposures rise to the level of a take. While studies, such as Miller

et al.

(1999), have indicated that some bowhead whales may have started to deflect from their migratory path 21.7 mi (35 km) from the seismic source vessel, it should be pointed out that these minor course changes occurred during migration and have not been seen at other times of the year and during other activities. To show the contextual nature of this minor behavioral modification, recent monitoring studies of Canadian seismic operations indicate that feeding, non-migratory bowhead whales do not move away from a noise source at a sound pressure level (SPL) of 160 dB. For predictive purposes, NMFS therefore continues to estimate takes from impulse noises such as seismic using the 160 dB (re 1 μPa) threshold.

According to experts on marine mammal behavior, whether a particular stressor could potentially disrupt behavioral patterns of migration, breathing, nursing, breeding, feeding, or sheltering, etc., of a marine mammal,

i.e.,

whether it would result in a take is complex and context specific, and it depends on several variables in addition to the received level of the sound by the animals. These additional variables include: Other source characteristics (such as frequency range, duty cycle, continuous vs. impulse vs. intermittent sounds, duration, moving vs. stationary sources, etc.); specific species, populations, and/or stocks; prior experience of the animals (naive vs. previously exposed); habituation or sensitization of the sound by the animals; and behavior context (whether the animal perceives the sound as predatory or simply annoyance), etc. (Southall

et al.

2007). The 120-dB and 160-dB acoustic criteria are generalized thresholds based on the available data that are intended to assist in a reasonably accurate assessment of take while acknowledging that sometimes animals will respond at received levels below those levels and sometimes they will not respond in a manner considered a take at received levels above them.

Comment 14:

The AWL disagree with NMFS assessment that “few seals are expected to occur in the proposed project area” and that “Shell's proposed activities would occur at a time of year when the ice seal species found in the region are not molting, breeding or pupping.” The AWL states that these statements are not supported. AWL states that Shell's proposed ice management and ice-breaking activities have the potential to disrupt essential ringed seal molting activities in July in a large region surrounding the drilling site, which could have harmful consequences for ringed seal survival.

Response:

The breeding and pupping season for Arctic ringed seal populations occurs from late March to mid-May, well before the proposed July 1 start date and after the conclusion of operations at the end of October (Kelly

et al.

2010). Although molting in some areas of the Arctic can extend into July, the molting period for ringed seals in the Chukchi Sea is primarily in May and June. This is evidenced by when the National Marine Mammal Laboratory conducted aerial surveys for ringed and bearded seals in 1999 and 2000, the surveys occurred in late May and early June at the peak of the molting/basking period (Bengtson

et al.

2005). Therefore, ice scouting and management activities in July and August, should they be necessary, will not occur during the period when most molting occurs. In addition to the fact that these activities are not expected to overlap with molting times, it is important to note that a large percentage of the anticipated takes will occur as a result of exposures that only just exceed the harassment threshold (

e.g.,

about 67% of the takes would be as a result of exposures between 120 and 126 dB), suggesting relatively minor and shorter term impacts that would have little to no likelihood of affecting an individual's fitness. Additionally, the estimated takes represent instances of take and do not account for the fact that the same individuals may be taken on more than one day, so the numbers of takes are an overestimate of individuals.

Comment 15:

The AWL states that ice management and ice-breaking activities, vessel traffic, and noise disturbance in September and October have the potential to displace large numbers of ringed seals and prevent them from occupying wintering areas and breeding areas in the offshore pack ice, with potential harm to survival.

Response:

NMFS considered the potential impacts of Shell's ice management efforts to ringed seals resting on pack ice in the Notice of Proposed IHA (80 FR 11726; March 4, 2015) in the section regarding anticipated effects on marine mammal habitat. NMFS noted that use of the icebreakers would occur outside of the ringed seal breeding and pupping seasons in the Chukchi Sea, and those ringed seal activities occur more commonly on landfast ice, which will not be affected by Shell's activity. Limited ice breaking might be needed to assist the fleet in accessing/exiting the project area if large amounts of ice pose a navigational hazard. Ice seals have variable responses to ice management activity. Alliston (1980, 1981) reported icebreaking activities did not adversely affect ringed seal abundance in the Northwest Territories and Labrador. Brueggeman

et al.

(1992) reported ringed seals and bearded seals diving into the water when an icebreaker was 0.58 mi (0.93 km) away. However, Kanik

et al.

(1980) reported that ringed seals remained on sea ice when an icebreaker was 0.62-1.24 mi (1-2 km) away.

The drill site is expected to be mostly ice-free during July, August, and September, and the need for ice management should be infrequent. The presence of an icebreaker is primarily a safety precaution to protect the drill ship from damage. Ice seals could be on isolated floes that may need to be managed for safety. Any ice seals on floes approaching the drill ship may be disturbed by ice management activities. Ringed seals on an ice floe are anticipated to enter the water before the icebreaker contacts the ice, remain in the water as the ice moves past the drill ship, and could reoccupy ice after it has moved safely past the drill ship. As was discussed in the proposed IHA notice, NMFS determined that this activity and these reactions would result in Level B harassment.

In addition, ice formation in October could begin to support haul-out of seals; however, wind and currents continually move and reshape the sea ice throughout the late-fall and early winter period. This movement of the pack ice continually opens new leads and breathing holes while closing old ones. Because the offshore pack ice continues to move and change throughout the winter and spring, breathing holes established in October, as described in shorefast ice locations, are unlikely to persist through the winter. Any disruption of newly forming sea ice in October by project vessels is not likely to cause any greater disturbance to the pack ice environment than will occur

through natural processes during the remainder of the ice-covered period.

Mitigation, Monitoring and Reporting

Comment 16:

The Commission notes that Shell would be required to monitor for marine mammals for 30 minutes before and continuously during airgun operations, but no post-activity monitoring. The Commission states that post-activity monitoring is needed to ensure that marine mammals have not been taken in unexpected or unauthorized ways or in unanticipated numbers. The Commission further states that some types of taking (

e.g.,

taking by death or serious injury) may not be observed until after the activity has ceased. Accordingly, the Commission recommends that NMFS require Shell to monitor for marine mammals for 30 minutes before airgun operations begin, while those activities are being conducted, and for 30 minutes after those operations have ceased.

Response:

NMFS agrees with the Commission's recommendation and revised the proposed IHA to require post-activity marine mammal monitoring for 30 minutes after Shell ceases activities.

Comment 17:

The Commission recommends that NMFS incorporate the peer review panel's recommendations into the IHA if issued.

Response:

NMFS conducted a peer review process to evaluate Shell's monitoring plan in early March 2015 in Anchorage, AK. The peer review panel submitted its report to NMFS in early April and provided recommendations to Shell. The panel's major recommendation was for Shell to modify the configuration of it passive acoustic arrays to evaluate the potential for spatial displacement of marine mammals. The panel also requested that the 90-day monitoring report include sightability curves for each species observed in the study area, and report concurrent collection of spatially overlapped visual and acoustic data to allow for a more detailed description of approximate acoustic detection ranges for the different species sighted and acoustically detected.

In addition, though not requested, the peer review panel also provided additional mitigation measures for bowhead whales or other large whale cow/calf pairs and aggregations, and during low visibility conditions; limiting the duration of mitigation gun to 30 minutes during repositioning; and turning off engines when vessels are stationary.

NMFS discussed with Shell the peer review panel report and went through a list of recommendations. As a result, Shell agrees to modify the deployment configuration of its passive acoustic monitoring to allow for evaluation of potential for spatial displacement of marine mammals. Shell also agreed to provide sightability curves and overlaying visual and acoustic detections in its 90-day report.

Regarding the mitigation measures recommended by the panel, Shell advised, and we agree, that the measures would not be practicable. For example, the VSP is planned to be conducted for just 10-14 hours total at different sediment depths at each site; a shutdown for cow/calf pairs and aggregation of bowhead whales and other large whales and during low visibility conditions would require Shell to restart the VSP, thus extending the duration of the VSP. In addition, the panel's recommended mitigation measures for turning off vessel engines while stationary would pose safety concerns. Therefore, these additional measures were not included in the IHA.

A detailed discussion on the peer review process and recommendations is provided in “

Monitoring Plan Peer Review”

section below.

Comment 18:

The NSB requests NMFS ensure that sufficient monitoring and mitigation requirements be implemented, and their effectiveness verified, to protect subsistence species, habitat and subsistence hunters. In addition, the NSB requests NMFS ensure that appropriate acoustic and visual monitoring be required.

Response:

Under the MMPA, NMFS must determine the taking from the specified activity 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). In addition, NMFS is required to prescribe the permissible methods of taking and other means of effecting the least practicable impact on the species or stock and their habitat and on the availability of the species or stock for taking for subsistence uses, as well as requirements pertaining to the monitoring and reporting of such takings.

Shell has worked with NMFS, as well as the affected subsistence communities, for multiple years on the continued development of its 4MP. The iterative evolution and review of the 4MP and its results indicates successful implementation by Shell, supports NMFS' impact analyses for this activity (

i.e.,

from the information gathered, impacts are within the scope and extent of those previously estimated) and, further, has added meaningfully to our understanding of the impacts of industrial activities on marine mammals. NMFS has conducted its own rigorous review and analysis of Shell's 4MP, and also had Shell's monitoring plan peer-reviewed by an independent peer-review panel (see below). Furthermore, the effectiveness of these monitoring and mitigation measures were evaluated by NMFS from Shell's 2012 monitoring reports, and deemed to be effective to protect subsistence species, habitat, and subsistence hunters.

These processes led NMFS to conclude that sufficient monitoring and mitigation requirements are prescribed in the IHA issued to Shell to protect subsistence species, habitat, and subsistence hunters. In addition, the IHA contains appropriate acoustic and visual monitoring requirements.

Comment 19:

Shell requests clarification on PSO monitoring requirement in the proposed IHA to reflect the 4MP to read:

“Utilize two, NMFS-approved vessel-based Protected Species Observers (PSOs) (except during meal times and restroom breaks, when at least one PSO will be on watch) aboard the drilling units to visually watch for and monitor marine mammals near the drilling units or support vessel during active drilling or airgun operations . . . day or night. At least one PSO will be aboard each support vessel to conduct watch.”

Response:

NMFS made the modification to clarify the PSO monitoring requirements and updated the language in the final IHA based on Shell's request.

Comment 20:

Regarding the requirement of making ZVSP sound source verification (SSV) measurements available to NMFS in 120 hours, Shell is concerned that this proposed requirement poses considerable safety issues and operations challenges. Shell stated that some of the recorders required to measure sound threshold radii of the ZVSP airgun array must be moored to the seafloor within the anchor pattern of the drilling unit. Recovery of these recorders while the drilling unit remains anchored will be unsafe. Grappling, the most reliable method of recovery, or recovery by acoustic release of the recorders, introduce risks to the crew of the drilling unit and the recovery vessel. These risks include entanglement of grappling lines with anchor lines, and disruption or disablement of critical communications equipment from acoustic interference. In addition, Shell states that it would conduct at most only one more ZVSP survey following measurement of the ZVSP airgun array,

and the ZVSP survey is only 10-14 hours in duration.

Response:

After further review of Shell's proposed specific activities and discussion with Shell, NMFS agrees with Shell's concern and removed the condition of requiring ZVSP SSV results 120 hours after the measurement. Instead, NMFS requires that ZVSP SSV results be made available in the 90-day monitoring report. NMFS further recognizes that the ZVSP acoustic footprint proposed by Shell for 2015 was modeled using JASCOs Marine Operations Noise Model, which is a reliable computation model for underwater acoustic propagation assessment. These model results were maximized over all water depths to identify the most protective 95th percentile distances to Level A thresholds, and then multiplied by 1.5 as an additional safeguard to ensure sufficient establishment of ZVSP exclusion zones for monitoring and mitigation. For these reasons, NMFS considers the modeled pre-season Level A exclusion zones adequate to protect marine mammals from injury.

Comment 21:

Shell requests NMFS remove the SSV reporting condition in the proposed IHA, which requires that:

“Preliminary vessel characterization measurements will be reported in a field report to be delivered 120 hours after the recorders are retrieved and the data downloaded.”

Shell states that it did not intend to include this requirement in the IHA application. Shell argues that one of its 2015 sound source characterization (SSC) of its exploration drilling program is a comprehensive analysis of underwater sound across the entire operational season, which necessitates that recorders remain deployed as long as is practicable. Further, Shell states that there is no connection between measurements of vessel sounds and mitigation, and Shell does not believe there is anything to be gained by reporting preliminary vessel measurements prior to a more comprehensive analysis of the data. Finally, Shell states that it will present detailed results of drilling and vessel SSCs in the 90-day report, as stated in the proposed IHA.

Response:

The proposed SSC reporting measurements was initially proposed by Shell in its 4MP. However, NMFS agrees with Shell's comment that leaving these recorders deployed for the entire project duration will collect valuable acoustic data on underwater noise across the entire operational season. NMFS made revision to the SSC condition in the IHA issued to Shell that requires Shell to present detailed results of drilling and vessel SSCs in its 90-day report.

Comment 22:

Shell points out that the following two proposed IHA mitigation measures regarding vessel movement seem to be contradictory:

“Avoid multiple changes in direction and speed when within 900 feet (300 yeards/274 m) of whales.” (7(b) of the proposed IHA)

“When weather conditions require, such as when visibility drops, support vessels must reduce speed and change direction, as necessary (and as operationally practicable), to avoid the likelihood of injury to whales.” (7(c) of the proposed IHA)

Shell states that the first proposed requirement is sufficient to meet mitigation objectives and avoid injury to whales, and requests NMFS to remove the second proposed requirement.

Response:

NMFS does not agree with Shell's assessment. The first proposed requirement (7(b) of the proposed IHA) would be in effect when a whale is sighted within 900 feet (300 yards/274 m) of a moving vessel and refers to avoiding

multiple

changes in direction in speed. In addition, 7(a) of the proposed IHA further requires all vessels to reduce speed to a maximum of 5 knots when a whale is detected at this distance. Item 7(c) is a general requirement for vessel transiting during poor visibility. Under this condition, vessels are required to travel at a reduced speed even no whale is in sight. NMFS believes that this condition is necessary to compensate for reduced whale detectability during poor visibility, to avoid ship strike. The IHA issued to Shell includes all these requirements.

Comment 23:

Shell points out that an important ZVSP mitigation measure was omitted from the proposed IHA that has been included in previous Arctic IHAs for marine seismic surveys. Shell recommends that the following mitigation measure be included in the IHA:

“If, for any reason, electrical power to the airgun array has been discontinued for a period of 10 minutes or more, ramp-up procedures shall be implemented. Only if the PSO watch has been suspended, a 30-minute clearance of the exclusion zone is required prior to commencing ramp-up. Discontinuation of airgun activity for less than 10 minutes does not require a ramp-up.”

Response:

NMFS agrees and included this measure in the final IHA issued to Shell.

Comment 24:

Shell states that the following language regarding PSOs is confusing:

“The Holder of this Authorization shall designate biologically-trained PSOs to be aboard the drilling units and all transiting support vessels.”

Shell states that the confusion lies between an academically degreed biologist and non-degreed biologist, both of which when properly trained can perform the duties of a PSO. Shell suggests we change the language to:

“The Holder of this Authorization shall designate trained PSOs aboard drilling units, icebreakers, and anchor handlers. All support vessels will be staffed with at least one trained PSO.”

Response:

NMFS agrees and revised the PSO language per Shell's recommendation. “Trained” requires that PSOs attend the training session described in this

Federal Register

Notice shortly before the start of the 2015 drilling season.

Comment 25:

The AWL states that the mitigation measures NMFS has proposed are inadequate for protecting marine mammals from adverse impacts. The AWL further states that NMFS has failed to analyze the full range of available mitigation measures, especially with regard to time/area restriction. The AWL specifically mentioned Hanna Shoal and migration corridors.

Response:

In order to issue an incidental take authorization (ITA) under the MMPA, NMFS must, where applicable, set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses (where relevant).

Concerning time/area closure, the IHA issued to Shell contains specific spatio-temporal requirements that Shell must follow to minimize or avoid impacts to subsistence harvest. Under the IHA issued to Shell, Shell is not permitted to enter the Chukchi Sea prior to July 1, 2015, which helps minimize impacts to the beluga hunt. In addition, Shell must finish drilling activities by October 31, 2015, which helps ensure that the drill ship and supporting vessels depart past Saint Lawrence Island before the Gambell bowhead whale harvest begins, thus minimizing potential impacts.

Regarding Hanna Shoal, we reviewed the literature and determined that although it has biological significance for walrus, a U.S. Fish and Wildlife species, there are no species under NMFS' jurisdiction for which Hanna Shoal has particular biological

importance. AWL did not mention other specific time/area closures.

One new publication compiles cetacean behavioral and distributional information to identify biologically important areas that are specifically used for feeding, migrating, or reproductive uses, or where small and resident populations are limited. Part of the northeastern Chukchi Sea is recognized as a bowhead whale reproductive biologically important area (BIA) from observation of calves there in October (Clarke

et al.

2015). Additionally, bowhead whales have also been observed feeding in this area during summer and fall; however, it is not recognized as a feeding BIA due to relatively fewer feeding observations (Clarke

et al.

2015). Additionally, in the northeastern Chukchi Sea, aerial survey sightings (Clarke & Ferguson, 2010; Clarke

et al.

2011, 2012, 2013), satellite telemetry (Quakenbush

et al.,

2010a, 2010b, 2013), and passive acoustic data (Hannay

et al.,

2013) indicate that the migration route in September and October is geographically broad (from the coast to > 400 km offshore); therefore, the northeastern Chukchi Sea does not meet the criteria for a migratory corridor BIA (Clarke

et al.

2015).

Portions of these areas utilized by bowhead whales for calving, feeding, and migration would be ensonified by Shell's proposed exploration drilling operation, although the size of the ensonified area will vary depending on the particular activity (

e.g.,

drilling, anchor handling, ZSVP, etc.). NMFS has considered time/area-based mitigation to reduce potential impacts to bowhead whale reproduction, feeding, and migration in regard to its BIAs. The only BIA that overlaps with Shell's exploration drilling is the bowhead reproduction BIA in the northeast Chukchi Sea in October and NMFS has already considered and discussed the potential for some small amount of behavioral harassment of mothers and calves, should they pass nearby the comparatively small area that may be ensonified by Shell's activities. Since Shell would only be conducting exploration drilling during a short four-month period, imposing a time/area limit of one month to avoid this time when calves might pass would mean a 25% reduction of Shell's work window, and would only likely avoid a small amount of harassment of mother/calf pairs. On balance, when the limited benefits of the measure are compared against the negative impacts to Shell's activities (either not completing the needed activities, or needing to extend them into additional seasons), NMFS considers it impracticable for the company to implement.

NMFS' analysis of the potential impacts of Shell's proposed exploration drilling on marine mammals species/stocks and subsistence activities indicates that Shell's activities would be limited to a small area in the Chukchi Sea during a four-month period in the 2015 open-water season. This is relatively small in both spatial and temporal scales when considering the total area of the Chukchi used by the affected marine mammal species or stocks for various activities, including migration.

NEPA Analysis

Comment 26:

The AWL states that NMFS must address cumulative, long-term effects of increased noise and other impacts from oil and gas activity properly before further activity is authorized.

Response:

Section 101(a)(5)(D) of the MMPA and its implementing regulations require NMFS to consider a request for the taking of marine mammals incidental to

a specified activity

within a specified geographical region and, assuming certain findings can be made, to authorize the taking of small numbers of marine mammals while engaged in that activity. NMFS has defined “specified activity” in 50 CFR 216.103 as “any activity, other than commercial fishing, that takes place in a specified geographical region and potentially involves the taking of small numbers of marine mammals.”

When making a negligible impact determination for an IHA, NMFS considers the total impact during each 1-year period resulting from the specified activity only and supports its determination by relying on factors such as: (1) The number of anticipated mortalities from the activity; (2) the number and nature of anticipated injuries from the activity; (3) the number, nature, intensity, and duration of Level B harassment resulting from the activity; (4) the context in which the takes occur; (5) the status of the species or stock; (6) environmental features that may significantly increase the potential severity of impacts from the proposed action; (7) effects on habitat that could affect rates of recruitment or survival; and (8) how the mitigation measures are expected to reduce the number or severity of takes or the impacts to habitat. When making its finding that there will be no unmitigable adverse impact on the availability of the affected species or stock for taking for subsistence uses, NMFS analyzes the measures contained in the applicant's Plan of Cooperation (POC). Additionally, Shell signed the 2012 Conflict Avoidance Agreement (CAA) with the AEWC. NMFS included all necessary measures from both documents in the IHA to ensure no unmitigable adverse impacts to subsistence.

Neither the MMPA nor NMFS' implementing regulations specify how to consider other activities and their impacts on the same populations when conducting a negligible impact analysis. However, consistent with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, September 29, 1989), the impacts from other past and ongoing anthropogenic activities are incorporated into the negligible impact analysis via their impacts on the environmental baseline (

e.g.,

as reflected in the density/distribution and status of the species, population size and growth rate, and ambient noise). Additionally, NMFS analyzed cumulative effects in NMFS' EA for the “

Issuance of an Incidental Harassment Authorization for the Take of Marine Mammals by Harassment Incidental to Conducting an Exploration Drilling Program in the U.S. Chukchi Sea”

and other relevant data to inform its MMPA determination here. Pursuant to the National Environmental Policy Act (NEPA), those documents contained a cumulative impacts assessment, as well as an assessment of the impacts of the proposed exploratory drilling program on marine mammals and other protected resources.

NMFS considered the impacts analyses (

i.e.,

direct, indirect, and cumulative) contained in the EA and other relevant NEPA documents cited in our response to comment 27 in reaching its conclusion that any marine mammals exposed to the sounds produced by the drillship, ice management/icebreaking vessels, support vessels and aircraft, and airguns would be disturbed for only a short period of time with no likely consequences for annual rates of recruitment or survival and would not be harmed or killed. Furthermore, the required mitigation and monitoring measures are expected to reduce the likelihood or severity of any impacts to marine mammal species or stocks or their habitats.

Moreover, NMFS gave careful consideration to a number of other issues and sources of information. In particular, NMFS relied upon a number of scientific reports, including the 2014 U.S. Alaska Marine Mammal Stock Assessment Reports (SARs), to support its findings. The SARs contain a description of each marine mammal stock, its geographic range, a minimum population estimate, current population

trends, current and maximum net productivity rates, optimum sustainable population levels and allowable removal levels, and estimates of annual human-caused mortality and serious injury through interactions with commercial fisheries and subsistence harvest data.

After careful consideration of the proposed activities, the context in which Shell's proposed activities would occur, the best available scientific information, and all effects analyses (including cumulative effects), NMFS has determined that the specified activities: (1) Would not result in more than the behavioral harassment (

i.e.,

Level B harassment) of small numbers of marine mammal species or stocks; (2) the taking by harassment would have a negligible impact on affected species or stocks; and (3) the taking by harassment would not have an unmitigable adverse impact on the availability of such species or stocks for taking for subsistence uses.

Comment 27:

NAEC states there is a lack of programmatic analysis of the effects of oil and gas exploration and development in the Arctic. Oceana claims that a programmatic environmental impact statement is needed to evaluate the environmental impacts of proposed and reasonably foreseeable oil and gas exploration in the Beaufort and Chukchi Seas. Both Oceana and AWL state that NMFS should not rely on an EA to evaluate the impacts of the proposed IHA.

Response:

NOAA prepared a Supplemental Draft Environmental Impact Statement on the Effects of Oil and Gas Activities in the Arctic Ocean (DEIS). The DEIS includes a broad range of potential offshore oil and gas activities in the Arctic that could affect marine mammals, other resources, and Alaska Native communities. While this EIS has not been finalized, and further considers a program including a more extensive amount of activity than is currently occurring, NMFS considers the analyses contained therein in the cumulative impact assessment of the current EA for the activity assessed here.

NMFS prepared an EA in 2012 to consider the effects of our 2012 IHAs for drilling in the Beaufort and Chukchi Seas, pending finalization of that EIS. For this IHA we prepared an EA, under similar reasoning we used in 2012. While the Final EIS is still under development, NMFS conducted a thorough analysis of the affected environment and the environmental consequences from exploratory drilling in the Chukchi Sea in 2015 and prepared an EA specific to Shell's proposed activity. The analysis in that EA warranted a Finding of No Significant Impact for issuance of an IHA to Shell for the incidental taking of marine mammals in the Chukchi Sea in 2015

In addition, BOEM prepared a Supplemental EIS (SEIS), published in February 2015, to analyze its estimate of the highest amount of production that could reasonably result from its Lease Sale 193. Information provided in our joint DEIS and BOEM's SEIS was considered in evaluating Shell's proposed exploration drilling impacts. In short, NOAA has considered the programmatic impacts and cumulative effects of multiple oil and gas exploration activities through multiple documents and analyses, the substance and conclusions (preliminary or final) of which have been considered in the current NEPA analysis for this action.

Comment 28:

While applauding NMFS for treating the no action alternative as a true no action alternative in its draft EA, and that for inclusion of two realistic alternatives that include fewer impacts than the preferred alternative, the AWL states that NMFS could explore a wider range of alternatives, including an alternative that requires the closures of particular areas.

Response:

In AWL's comments, it suggested Hanna Shoal could be considered for time/area closure. However, as discussed in Response to Comment 25, Hanna Shoal is not an important habitat for marine mammals under NMFS' jurisdiction, and the IHA contains other spatio-temporal restrictions that bound its effective dates. The alternatives NMFS considered in its draft EA are: (1) Issuance of an authorization with mitigation measures (Preferred Alternative); (2) Issuance of an IHA for a shorter time period with required mitigation, monitoring, and reporting requirements (Alternative 2); (3) Issuance of an IHA to drill one well with required mitigation, monitoring, and reporting requirements (Alternative 3); and (4) No issuance of the request IHA to Shell for its exploration drilling activities (Alternative 4—the No Action Alternative). Other alternatives considered but rejected from further consideration include: (1) Issuance of an IHA with no required mitigation, monitoring, or reporting measures; and (2) Use of alternative technologies. Since Shell's proposed exploration drilling activities in the 2015 Arctic open-water season in Chukchi Sea occupies a small area and will have a limited noise footprint around its drill platforms and ice management and icebreaking vessels and other support vessels around the drilling vicinity, and further that footprint is not within an area of heightened importance for marine mammals (with the exception to bowhead whale reproduction in October, see

Response to Comment 25

above) or subsistence uses, NMFS does not consider the closure of a particular area would be a meaningful alternative. We also note that Alternative 3, issuance of IHA to drill one well with required mitigation, monitoring, and reporting requirements, considers a spatial limitation on the area Shell would affect.

Comment 29:

AWL states that NMFS draft EA does not contain original analysis of cumulative impacts of climate change for this IHA, and that the most recent study cited in reference to climate change analysis is from 2011.

Response:

As explained by the Council on Environmental Quality, an EA is a concise document and should not contain long descriptions or detailed data which the agency may have gathered. Rather, it should contain a brief discussion of the need for the proposal, alternatives to the proposal, the environmental impacts of the proposed action and alternatives, and a list of agencies and persons consulted. See NEPA's Forty Most Asked Questions, 46 FR 18026 (March 23, 1981); 40 CFR 1508.9(b). The EA prepared for this action contains a cumulative effects analysis that includes consideration of climate change and incorporates by reference several original studies on climate change (ACIA 2004; Raven

et al.

2005; IPCC 2007; Fabry

et al.

2009; Mathis 2011). An assessment of the IHA for Shell's drilling activity and its added contribution to cumulative impacts of climate change on the environment was conducted based on these studies. An exhaustive search of the most recent studies did not show that NMFS missed any critical information in conducting the analysis. In its comment, the AWL did not point out any additional new scientific information that NMFS should take into consideration in its climate change analysis. We also note that climate change is considered in BOEM's SEIS for Lease Sale 193 and NMFS' draft EIS for the Arctic.

Impacts on Subsistence

Comment 30:

The AEWC states that the analysis in the

Federal Register

of potential impacts to subsistence uses should begin with a discussion of whether the operator has signed the Conflict Avoidance Agreement (CAA) and, if so, what the CAA includes as

mitigation measures for the subsistence activities.

Response:

NMFS has defined “unmitigable adverse impact” in 50 CFR 216.103 as: An impact resulting from the specified activity: (1) That is likely to reduce the availability of the species to a level insufficient for a harvest to meet subsistence needs by: (i) Causing the marine mammals to abandon or avoid hunting areas; (ii) Directly displacing subsistence users; or (iii) Placing physical barriers between the marine mammals and the subsistence hunters; and (2) That cannot be sufficiently mitigated by other measures to increase the availability of marine mammals to allow subsistence needs to be met. The analysis of potential impacts to subsistence uses depends on more information than solely whether the applicant has signed a CAA. Nevertheless, in our analysis, we did consider the CAA negotiation between the Shell and the Native subsistence users. Where measures outlined in the CAA are also necessary to ensure an unmitigable adverse impact to subsistence uses, NMFS includes them as required measures in the IHA. In the

Federal Register

notice for the proposed IHA, NMFS noted that Shell attended the 2012-2014 CAA negotiation meetings in support of exploration drilling, offshore surveys, and future drilling plans. In addition, Shell informed NMFS that it would do the same for the upcoming 2015 exploration drilling program, and Shell has signed the 2015 CAA.

Comment 31:

The AEWC notes that the proposed IHA for Shell incorporates mitigation measures from the CAA, including the use of protected species observers (PSOs) and Inupiat Communicators, the Com-Centers and the general communications scheme, sound source verification, monitoring plans, cumulative noise impacts study, and general provisions for avoiding interference with bowhead whales or subsistence whale hunting activities. However, AEWC points out that additional mitigation measures from the CAA should also be included in the IHA, including: Standardized Log Books (CAA Section 204) and Shore-Based Service and Supply Areas (CAA Section 504). The AEWC recommends these measures be included under Section 9 of the IHA.

Response:

NMFS considered whether implementing Standardized Log Books and Shore-Based Service and Supply Areas was necessary to reach a finding of no unmitigable adverse impact on availability of marine mammals for taking for subsistence or appropriate for effecting the least practicable impact on the availability of the species or stock for taking for subsistence uses, and in both cases determined they were not. The recommendation of Standardized Log Books requires that industry participants provide the Com-Centers and Marine Mammal Observer/Inupiat Communicators with identical log books to assist in the standardization of record keeping associated with communications procedures. NMFS further clarified with AEWC on this issue and understands that the log books would serve a record-keeping function at times in determining sources of disturbance by the AEWC. The AEWC would like to have a coherent record of activities and communications. The AEWC further states that as non-industry vessel traffic increases (

i.e.,

research, commercial, and marine tourism vessels), the ability to track communications through the Com Centers and along the coast is going to become important.

NMFS has already been requiring Shell and other companies to use standardized format for marine mammal monitoring under the recommendation by peer-review panel. We again require Shell to provide detailed records of all marine mammal sightings and its activities under the IHA. In addition, Shell is required to produce a draft comprehensive report that integrates the studies into a broad based assessment of all industry activities and their impacts, which will be made available to NMFS, AEWC, and NSB for review. Furthermore, Shell is required to communicate with Com Centers for all its activities that could affect subsistence resources. Finally, as Shell already signed a CAA with AEWC, this condition prescribed in the CAA will serve as a form of agreement between AEWC and Shell on these issues.

Regarding the Shore-Based Service and Supply Areas provision, NMFS reached out to the AEWC for clarification of this recommendation. AEWC states that this simply means that the mitigation measures run both prospect-to-shore and shore-to-prospect. Therefore, NMFS does not believe that this requirement would add additional value to NMFS determination of no-unmitigable impact.

Comment 32:

The AEWC requests NMFS include a condition requiring Shell to complete exit transit through the Bering Strait to a point south of 59 degrees North latitude no later than November 15, 2015. In addition, the AEWC requests NMFS require that any industry participant vessel that encounters weather or ice that will prevent compliance with the date shall coordinate its transit through the Bering Strait to a point south of 59 degrees North latitude with the appropriate Com-Centers, and that all industry participant vessels shall, weather and ice permitting, transit east of St. Lawrence Island and no closer than 10 miles from the shore of St. Lawrence Island.

Response:

Shell signed the 2015 CAA with the AEWC on April 23, 2015. In the signed 2015 CAA, Shell agreed to establish Communication Centers in the Bering Sea communities and will conduct such communications in the manner laid out in the CAA and the IHA. Shell's IHA is valid for drilling operations through October 31. Therefore, demobilization and transit out of the area will begin by that date. Information shared with NMFS from hunters on St. Lawrence Island noted that the fall bowhead whale hunts typically occur the week of Thanksgiving. For example, in 2012, 1 bowhead whale was harvested on November 27 and 1 on November 30 in the community of Savoonga, and 1 bowhead was harvested on November 27 in the community of Gambell. In 2013, 1 bowhead was harvested on December 4 and 1 on December 6 in Savoonga, and no fall whale harvest in Gambell.

In addition, vessel transit route through the Bering Strait will follow a route well east of St. Lawrence Island, placing vessels more than 60 miles and 90 miles east of the communities of Savoonga and Gambell, respectively. Furthermore, Shell will communicate with all communities via its Com Centers as vessels depart the operating area and transit into the Bering Sea to ensure that vessel transit does not interfere with any hunt.

Comment 34:

The NSB states that it has repeatedly asked that industry not enter the Chukchi Sea until after July 15th, which will allow for the completion of the beluga whale hunt in Point Lay. The NSB states that this will help mitigate some of the impacts to the subsistence harvests. The NSB states that it has heard from Shell that they do not anticipate arriving until after this date; yet under the proposed IHA Shell would be permitted to move into the Chukchi Sea beginning on July 1.

Response:

Shell requested take coverage beginning July 1 (Shell 2015). Upon receiving NSB's comment, NMFS further verified with Shell its intended project dates for the exploration drilling program during the 2015 Arctic open-water season, and again Shell emphasized that it is critical for Shell to enter Chukchi Sea through Bering Strait on or after July 1. This timeframe for entry has been an annual component of

Shell's plans to conduct exploration drilling in the Chukchi Sea since 2009. To address subsistence impact concerns, Shell developed a robust Subsistence Advisor (SA) program within our POC, also adding a Communication Plan for direct communication and real-time avoidance of impacts to subsistence users and marine mammals. This is specifically detailed on page 12-2 of Shell's IHA application. The SA program and Communication Plan within that program have been in place since 2009 and remain due to the proven capability of avoiding impacts to subsistence harvests regardless of the location or timing of those harvests in the Chukchi and Beaufort Seas. Again in 2015, Shell will have SAs and Community Liaisons in place and Communication Centers (Com Centers) active along the coasts of the Bering and Chukchi Seas, to carry out the POC.

Shell's general marine vessel route is approximately 54 nautical miles offshore of Pt. Lay. Vessels transiting offshore of Point Lay will generally be far outside of areas traditionally used by Pt. Lay residents for beluga whale subsistence hunting. Therefore, Shell's vessels will be positioned well offshore and it is highly unlikely that routine vessel transits will impede subsistence users' access to beluga whales or cause them to divert from their normal migratory route.

Finally, Shell is required implement a number of mitigation measures to minimize any potential adverse impacts on subsistence users. These include the use of Subsistence Advisors, Community Liaison Officers, and Com Centers, which will be established and utilized on a daily basis to coordinate and modify vessel traffic based on current or anticipated subsistence activities. Thus, given the distance of vessel traffic in relation to subsistence hunting activities, and with the implementation of appropriate mitigation measures, NMFS does not believe Shell's entering of the Chukchi Sea prior to July 15 will adversely affect beluga whale harvest in Point Lay.

Comment 35:

The NSB requests NMFS require Shell to coordinate with the AEWC and other Alaska Native marine mammal user groups as appropriate, and participate in the well-established and effective Conflict Avoidance Agreement (CAA) process.

Response:

Throughout the incidental take authorization processing for the 2015 Arctic open-water industry activities, NMFS has been working with stakeholders including the AEWC and other Alaska Native marine mammal user groups as appropriate to conduct its analysis on the potential impacts of the drilling program on subsistence activities. A peer-review meeting on industry's monitoring plans was held in early March 2015 in Anchorage, and NMFS invited a representative from the AEWC to observe the peer-review process.

Shell signed the 2015 CAA with the AEWC on April 23, 2015. The CAA is a document that is negotiated between and signed by the industry participant and subsistence user groups such as AEWC and the Village Whaling Captains' Associations. NMFS has no role in the development or execution of this agreement. Although the contents of a CAA may inform NMFS' no unmitigable adverse impact determination for marine mammal subsistence impacts, the signing of a CAA is not a requirement. NMFS' MMPA implementing regulations require that for an activity that will take place near a traditional Arctic hunting ground, or may affect the availability of marine mammals for subsistence uses, an applicant for MMPA authorization must either submit a Plan of Cooperation (POC) or information that identifies the measures that have been taken to minimize adverse impacts on subsistence uses. Shell submitted a POC with its IHA application, which was available during the public comment period.

NMFS (or other Federal agencies) has no authority to require agreements between third parties, and NMFS would not be able to enforce the provisions of CAAs because the Federal government is not a party to the agreements. Regarding the CAA signed with the AEWC, NMFS has reviewed that document, as well as Shell's POC. The majority of the conditions are identical between the two documents. NMFS' IHA includes measures from the 2015 CAA between Shell and the AEWC that we believe are relevant to ensuring no unmitigable adverse impact on the availability of marine mammals for subsistence uses.

Miscellaneous

Comment 36:

Shell points out that the 180 dB re 1 μPa rms radius for zero-offset vertical seismic profile (ZVSP) should be 1.38 km, not 1.28 km as stated on page 11773 of the

Federal Register

notice for the proposed IHA (80 FR 11726; March 4, 2015).

Response:

NMFS recognizes that this is a typographic error and made the correction. This error does not affect the results of the analysis since the analysis was conducted on the correct radius of 1.38 km. NMFS has corrected the error in the IHA issued to Shell.

Comment 37:

The NSB requests NMFS require Shell to use the best available technologies and best management practices for both seismic and exploratory drilling, including zero discharge.

Response:

Shell's collection of drilling mud and cuttings and certain other waste streams is a voluntary decision on the part of the company for its Beaufort Sea exploratory drilling program. Shell will not be conducting such a program in the Chukchi Sea, a practice that is consistent with both the current Arctic Oil and Gas Exploration General Permit and the draft General Permit being considered by the U.S. Environmental Protection Agency. The discharge of drilling related effluents has been extensively studied in both temperate and Arctic regions (Neff, 2010) and, when employing water based muds, is generally considered to be of slight environmental impact. The removal of muds, cuttings, and other effluent streams from exploration drilling requires additional vessels, which results in additional vessel traffic and related noise (which can in turn increase the potential for vessel-marine mammal interactions and vessel-related air emissions). Given the concerns raised with respect to the cumulative impacts of vessel traffic in the Arctic, the speculative benefits of waste stream removal do not warrant imposing such a requirement on Shell in the Chukchi Sea. Shell will, however, collect water and other samples in both seas before, during, and after the drilling programs in order to study sediment and water chemistry, the biotic community, deposition, and bioaccumulation. The collection of these samples will repeat evaluations at the localized drill sites that have been conducted as part of the Joint Industry Monitoring Program for several years. NMFS has determined that even without requiring such a measure, Shell's activities will have a negligible impact on marine mammal species or stocks and will not have an unmitigable adverse impact on the availability of marine mammals for taking for subsistence uses.

Comment 38:

Several private citizens are concerned about potential oil spill from Shell's exploration drilling program in the Chukchi Sea.

Response:

NMFS' Notice of Proposed IHA contained information regarding measures Shell has instituted to reduce the possibility of a major oil spill during its operations, as well as potential impacts on cetaceans and pinnipeds, their habitats, and subsistence activities (80 FR 11726; March 4, 2015). NMFS' EA also contains an analysis of the potential effects of an oil spill on marine

mammals, their habitats, and subsistence activities. Much of that analysis is incorporated by reference from other NEPA documents prepared for activities in the region. There is no information regarding potential take from a release of oil because an oil spill is not a component of the “specified activity.”

The Bureau of Ocean Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BESS) under the Department of the Interior (DOI) are the agencies with expertise in assessing risks of an oil spill. In reviewing Shell's Chukchi Sea Exploration Plan and Regional Oil Spill Response Plan (OSRP), BOEM and BSEE determined that the risk was low and that Shell will implement adequate measures to further minimize the risk. Shell's OSRP identifies the company's prevention procedures; estimates the potential discharges and describes the resources and steps that Shell would take to respond in the unlikely event of a spill; and addresses a range of spill volumes, ranging from small operational spills to the worst case discharge calculations required to account for the unlikely event of a blowout. Additionally, in 2012 NOAA's Office of Response and Restoration reviewed Shell's OSRP and provided input to DOI requesting changes to the plan before it should be approved. Shell incorporated NOAA's suggested changes, which included updating the trajectory analysis and the worst case discharge scenario. Based on these revisions, NOAA's Office of Response and Restoration determined that Shell's plans to respond to an offshore oil spill in the U.S. Arctic Ocean are satisfactory, as stated in a 2012 memorandum provided to NMFS by the Office of Response and Restoration. Lastly, in the unlikely event of an oil spill, Shell will conduct response activities in accordance with NOAA's Marine Mammal Oil Spill Response Guidelines.

Description of Marine Mammals in the Area of the Specified Activity

The Chukchi Sea supports a diverse assemblage of marine mammals, including: Bowhead, gray, beluga, killer, minke, humpback, and fin whales; harbor porpoise; ringed, ribbon, spotted, and bearded seals; narwhals; polar bears (

Ursus maritimus

); and walruses (

Odobenus rosmarus divergens;

see Table 4-1 in Shell's application). The bowhead, humpback, and fin whales are listed as “endangered” under the Endangered Species Act (ESA) and as depleted under the MMPA. The ringed seal is listed as “threatened” under the ESA. Certain stocks or populations of gray, beluga, and killer whales and spotted seals are listed as endangered or are proposed for listing under the ESA; however, none of those stocks or populations occur in the proposed activity area. Both the walrus and the polar bear are managed by the U.S. Fish and Wildlife Service (USFWS) and are not considered further in this IHA notice.

Of these species, 12 are expected to occur in the area of Shell's proposed operations. These species are: The bowhead, gray, humpback, minke, fin, killer, and beluga whales; harbor porpoise; and the ringed, spotted, bearded, and ribbon seals. Beluga, bowhead, and gray whales, harbor porpoise, and ringed, bearded, and spotted seals are anticipated to be encountered more than the other marine mammal species mentioned here. The marine mammal species likely to be encountered most widely (in space and time) throughout the period of the proposed drilling program is the ringed seal. Encounters with bowhead and gray whales are expected to be limited to particular seasons, as discussed later in this document. Where available, Shell used density estimates from peer-reviewed literature in the application. In cases where density estimates were not readily available in the peer-reviewed literature, Shell used other methods to derive the estimates. The explanation for those derivations and the actual density estimates are described later in this document (see the “Estimated Take by Incidental Harassment” section).

The narwhal occurs in Canadian waters and occasionally in the Alaskan Beaufort Sea and the Chukchi Sea, but it is considered extralimital in U.S. waters and is not expected to be encountered. There are scattered records of narwhal in Alaskan waters, including reports by subsistence hunters, where the species is considered extralimital (Reeves

et al.,

2002). Due to the rarity of this species in the proposed project area and the remote chance it would be affected by Shell's proposed Chukchi Sea drilling activities, this species is not discussed further in this IHA notice.

Shell's application contains information on the status, distribution, seasonal distribution, abundance, and life history of each of the species under NMFS jurisdiction mentioned in this document. NMFS consideration of this application later took into account updated information on bowhead and beluga whale densities. See “Estimated Take by Incidental Harassment” section later in this notice. Additional information can also be found in the NMFS Stock Assessment Reports (SAR). The Alaska 2013 SAR is available at:

http://www.nmfs.noaa.gov/pr/sars/pdf/ak2013_final.pdf.

Table 1 lists the 12 marine mammal species or stocks under NMFS jurisdiction with confirmed or possible occurrence in the proposed project area.

Table 1—Marine Mammal Species and Stocks With Confirmed or Possible Occurrence in the Proposed Exploration Drilling Area

Common name

Scientific name

Status

Occurrence

Seasonality

Range

Abundance

Odontocetes:

Beluga whale (Eastern Chukchi Sea stock)

Dephinapterus leucas

Common

Mostly spring and fall with some in summer

Russia to Canada

3,710

Beluga whale (Beaufort Sea stock)

Delphinapterus leucas

Common

Mostly spring and fall with some in summer

Russia to Canada

39,258

Killer whale

Orcinus orca

Occasional/Extralimital

Mostly summer and early fall

California to Alaska

2,084

Harbor porpoise

Phocoena phocoena

Occasional/Extralimital

Mostly summer and early fall

California to Alaska

48,215

Mysticetes:

Bowhead whale

Balaena mysticetus

Endangered; Depleted

Common

Mostly spring and fall with some in summer

Russia to Canada

19,534

Gray whale

Eschrichtius robustus

Somewhat common

Mostly summer

Mexico to the U.S. Arctic Ocean

19,126

Minke whale

Balaenoptera acutorostrata

Rare

Summer

North Pacific

810-1,003

Fin whale (North Pacific stock)

B. physalus

Endangered; Depleted

Rare

Summer

North Pacific

1,652

Humpback whale (Central North Pacific stock)

Megaptera novaeangliae

Endangered; Depleted

Rare

Summer

Central to North Pacific

20,800

Pinnipeds:

Bearded seal (Beringia distinct population segment)

Erigathus barbatus

Candidate

Common

Spring and summer

Bering, Chukchi, and Beaufort Seas

155,000

Ringed seal (Arctic stock)

Phoca hispida

Threatened; Depleted

Common

Year round

Bering, Chukchi, and Beaufort Seas

300,000

Spotted seal

Phoca largha

Common

Summer

Japan to U.S. Arctic Ocean

141,479

Ribbon seal

Histriophoca fasciata

Species of concern

Occasional

Summer

Russia to U.S. Arctic Ocean

49,000

Potential Effects of the Specified Activity on Marine Mammals

The primary potential impacts to marine mammals and other marine species are associated with elevated sound levels produced by the exploratory drilling program (

i.e.,

the drillship and the airguns). The proposed IHA contains a full discussion of the potential impacts to marine mammal species in the project area. No changes have been made to that discussion, exception a clarification made on marine mammal functional hearing groups, which is discussed in

Response to Comment 4

above. Please refer to the proposed IHA for the full discussion of potential impacts to marine mammal (80 FR 11726, March 4, 2015). NMFS has determined that Shell's exploratory drilling program would only result in Level B behavioral harassment of marine mammals, and will not cause hearing threshold shifts, injury, and/or mortality to marine mammals exposed to noise generated from Shell's activities.

Anticipated Effects on Marine Mammal Habitat

The primary potential impacts to marine mammals and other marine species are associated with elevated sound levels produced by the exploratory drilling program (

i.e.,

the drillship and the airguns). However, other potential impacts are also possible to the surrounding habitat from physical disturbance and an oil spill (should one occur). The proposed IHA contains a full discussion of the potential impacts to marine mammal habitat and prey species in the project area. No changes have been made to that discussion. Please refer to the proposed IHA for the full discussion of potential impacts to marine mammal habitat (80 FR 11726, March 4, 2015). NMFS has determined that Shell's exploratory drilling program is not expected to have any habitat-related effects that could cause significant or long-term consequences for marine mammals or on the food sources that they utilize.

Mitigation

In order to issue an incidental take authorization (ITA) under section 101(a)(5)(D) of the MMPA, NMFS must, where applicable, set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses (where relevant). This section summarizes the mitigation measures Shell is required to implement under the IHA. In summary, the following changes have been made to the mitigation since the proposed IHA was published: Requiring ramp-up procedure if ZVSP airgun has been discontinued for a period of 10 minutes or more, and when utilizing the mitigation airgun for position change, use a reduced duty cycle (approximately 1 shot per 5 minutes).

Vessel Based Marine Mammal Monitoring for Mitigation (and Other Purposes)

The objectives of the vessel based marine mammal monitoring are to ensure that disturbance to marine mammals and subsistence hunts is minimized, that effects on marine mammals are documented, and that data is collected on the occurrence and distribution of marine mammals in the project area.

The marine mammal monitoring will be implemented by a team of protected species observers (PSOs). The PSOs will be biologists and Alaska Native personnel trained as field observers. PSOs will be stationed on both drilling units, ice management vessels, anchor handlers and other drilling support vessels engaged in transit to and between drill sites to monitor for marine mammals. The duties of the PSOs will include: Watching for and identifying marine mammals, recording their numbers, recording distances and reactions of marine mammals to exploration drilling activities, initiating mitigation measures when appropriate, and reporting results of the vessel based monitoring program, which will include the estimation of the number of marine mammal “exposures” as defined by the NMFS and stipulated in the IHA.

The vessel based work will provide:

• The basis for initiating real-time mitigation, if necessary, as required by the various permits that Shell receives;

• Information needed to estimate the number of “exposures” of marine mammals to sound levels that may

result in harassment, which must be reported to NMFS;

• Data on the occurrence, distribution, and activities of marine mammals in the areas where drilling activity is conducted;

• Information to compare the distances, distributions, behavior, and movements of marine mammals relative to the drilling unit during times with and without drilling activity occurring;

• A communication channel to coastal communities including whalers; and

• Employment and capacity building for local residents, with one objective being to develop a larger pool of experienced Alaska Native PSOs.

The vessel based monitoring will be operated and administered consistent with monitoring programs conducted during past exploration drilling activities, seismic and shallow hazards surveys, or alternative requirements stipulated in permits issued to Shell. Agreements between Shell and other agencies will also be fully incorporated. PSOs will be provided training through a program approved by the NMFS.

Mitigation Measures During the Exploration Drilling Program

Shell's planned exploration drilling activities incorporate design features and operational procedures aimed at minimizing potential impacts on marine mammals and subsistence hunts. Some of the mitigation design features include:

• Conducting pre-season acoustic modeling to establish the appropriate exclusion and disturbance zones;

• Vessel based PSO monitoring to implement appropriate mitigation if necessary, and to determine the effects of the drilling program on marine mammals;

• Passive acoustic monitoring of drilling and vessel sounds and marine mammal vocalizations; and

• Aerial surveys with photographic equipment over operations and in coastal and nearshore waters with photographic equipment to help determine the effects of project activities on marine mammals; and seismic activity mitigation measures during acquisition of the ZVSP surveys.

The potential impacts on marine mammals during drilling activities will be mitigated through the implementation of several vessel based mitigation measures as necessary.

(1) Exclusion and Disturbance Zones

Mitigation for NMFS' incidental take authorizations typically includes “safety radii” or “exclusion zones” for marine mammals around airgun arrays and other impulsive industrial sound sources where received levels are ≥180 dB re 1 μPa (rms) for cetaceans and ≥190 dB re 1 μPa (rms) for pinnipeds. These zones are based on a cautionary assumption that sound energy at lower received levels will not injure these animals or impair their hearing abilities, but that higher received levels might have some such effects. Disturbance or behavioral effects to marine mammals from underwater sound may occur from exposure to sound at distances greater than these zones (Richardson

et al.

1995). The NMFS assumes that marine mammals exposed to pulsed airgun sounds with received levels ≥160 dB re 1 μPa (rms) or continuous sounds from vessel activities with received levels ≥120 dB re 1 μPa (rms) have the potential to be disturbed. These sound level thresholds are currently used by NMFS to define acoustic disturbance (harassment) criteria.

(A) Exploration Drilling Activities

The areas exposed to sounds produced by the drilling units

Discoverer

and

Polar Pioneer

were determined by measurements from drilling in 2012 or were modeled by JASCO Applied Sciences. The 2012 measurement of the distance to the 120 dB (rms) threshold for normal drilling activity by the

Discoverer

was 0.93 mi (1.5 km) while the distance of the ≥120 dB (rms) radius during MLC construction was 5.1 mi (8.2 km).

Measured sound levels for the

Polar Pioneer

were not available. Its sound footprint was estimated with JASCOs Marine Operations Noise Model (MONM) using an average source level derived from a number of reported acoustic measurements of comparable semi-submersible drill units, including the Ocean Bounty (Gales, 1982), SEDCO 708 (Greene, 1986), and Ocean General (McCauley, 1998). The model yielded a propagation range of 0.22 mi (0.35 km) for rms sound pressure levels of 120 dB for the

Polar Pioneer

while drilling at the Burger Prospect.

In addition to drilling and MLC construction, numerous activities in support of exploration drilling produce continuous sounds above 120 dB (rms). These activities in direct support of the moored drilling units include ice management, anchor handling, and supply/discharge sampling vessels using DP thrusters. Detailed sound characterizations for each of these activities are presented in the 2012 Comprehensive Report for NMFS' 2012 IHA (LGL

et al.

2013).

The source levels for exploration drilling and related support activities are not high enough to cause temporary reduction in hearing sensitivity or permanent hearing damage to marine mammals. Consequently, mitigation as described for seismic activities. including ramp ups, power downs, and shut downs, are not required for exploration drilling activities. However, Shell will use PSOs onboard the drilling units, ice management, and anchor handling vessels to monitor marine mammals and their responses to industry activities, in addition to initiating mitigation measures should in-field measurements of the activities indicate conditions that may present a risk of unanticipated impacts on marine mammals.

(B) ZVSP Surveys

Two sound sources have been proposed by Shell for the ZVSP surveys. The first is a small airgun array that consists of three 150 in

3

(2,458 cu cm3) airguns for a total volume of 450 in

3

(7,374 cm

3

). The second ZVSP sound source consists of two 250 in

3

(4,097 cm

3

) airguns with a total volume of 500 in

3

(8,194 cm

3

). Sound footprints of the ZVSP airgun array configurations were estimated using JASCO Applied Sciences' Marine Operations Noise Model (MONM). The model results were maximized over all water depths between 9.9 and 23 ft (3 and 7 m) to yield sound level isopleths as a function of range and direction from the source. The 450 in

3

airgun array at a source depth of 23 ft (7 m) yielded the maximum ranges to the ≥190, ≥180, and ≥160 dB (rms) isopleths. The estimated 95th percentile distances to these thresholds were: 190 dB = 558 ft (170 m), 180 dB = 3,018 ft (920 m), and 160 dB = 39,239 ft (11,960 m). These distances were multiplied by 1.5 as a conservative measure, and the resulting radii are shown in Table 2.

PSOs on the drilling units will initially use the radii in Table 2 for monitoring and mitigation purposes during ZVSP surveys. An acoustics contractor will perform direct measurements of the received levels of underwater sound versus distance and direction from the ZVSP array using calibrated hydrophones. The mitigation measures to be implemented will include pre-ramp up watches, ramp ups, power downs and shut downs as described below.

Table 2—Estimated Distances of the ≥190, 180, and 160, dB (rms) Isopleths To Be Used for Mitigation Purposes During ZVSP Surveys Until SSV Results are Available

Threshold levels in dB

re 1 μPa

(rms)

Estimated

distance

(m)

≥190

255

≥180

1,380

≥160

11,960

(2) Ramp Ups

A ramp up of an airgun array provides a gradual increase in sound levels, and involves a step-wise increase in the number and total volume of airguns firing until the full volume is achieved. The purpose of a ramp up (or “soft start”) is to “warn” cetaceans and pinnipeds in the vicinity of the airguns and to provide time for them to leave the area, thus avoiding any potential injury or impairment of their hearing abilities from higher levels of exposure.

Shell contact NMFS and clarified the operations of ZVSP uses and stated that during the proposed ZVSP surveys, the operator will ramp up the airgun arrays slowly. Full ramp ups (

i.e.,

from a cold start when no airguns have been firing) will begin by firing a single airgun in the array. A full ramp up will not begin until there has been observation of the exclusion zone by PSOs for a minimum of 30 minutes to ensure that no marine mammals are present. The entire exclusion zones must be visible during the 30 minutes leading into to a full ramp up. If the entire exclusion zone is not visible, a ramp up from a cold start cannot begin. If a marine mammal is sighted within the relevant exclusion zone during the 30 minutes prior to ramp up, ramp up will be delayed until the marine mammal is sighted outside of the exclusion zone or is not sighted for at least 15-30 minutes: 15 minutes for small odontocetes and pinnipeds, or 30 minutes for baleen whales and large odontocetes.

In addition, if for any reason, use of the airgun array has been discontinued for a period of 10 minutes or more, ramp-up procedures shall be implemented. Only if the PSO watch has been suspended, a 30-minute clearance of the exclusion zone is required prior to commencing ramp-up. Discontinuation of airgun activity for less than 10 minutes does not require a ramp-up; and

Further, when utilizing the mitigation airgun during position/depth change, use a reduced duty cycle (approximately 1 shot every 5 minutes).

(3) Power Downs and Shut Downs

A power down is the immediate reduction in the number of operating energy sources from all firing to some smaller number. A shut down is the immediate cessation of firing of all energy sources. The arrays will be immediately powered down whenever a marine mammal is sighted approaching close to or within the applicable exclusion zone of the full arrays, but is outside the applicable exclusion zone of the single source. If a marine mammal is sighted within the applicable exclusion zone of the single energy source, the entire array will be shut down (

i.e.,

no sources firing).

After a complete shutdown of the airgun due to detection of a marine mammal in the vicinity, airguns cannot be restarted until the marine mammal is visually sighted leaving the exclusion zone, or is not sighted for at least 15-30 minutes: 15 minutes for small odontocetes and pinnipeds, or 30 minutes for baleen whales and large odontocetes.

(4) Loss of Electrical Power to Airgun Array

If, for any reason, electrical power to the airgun array has been discontinued for a period of 10 minutes or more, ramp-up procedures shall be implemented. If the PSO watch has been suspended, a 30-minute clearance of the exclusion zone is required prior to commencing ramp-up. Discontinuation of airgun activity for less than 10 minutes does not require a ramp-up.

Mitigation Conclusions

NMFS has carefully evaluated the applicant's mitigation measures and considered a range of other measures in the context of ensuring that NMFS prescribes the means of effecting the least practicable impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another:

• The manner in which, and the degree to which, the successful implementation of the measure is expected to minimize adverse impacts to marine mammals;

• The proven or likely efficacy of the specific measure to minimize adverse impacts as planned; and

• The practicability of the measure for applicant implementation.

Any mitigation measure(s) prescribed by NMFS should be able to accomplish, have a reasonable likelihood of accomplishing (based on current science), or contribute to the accomplishment of one or more of the general goals listed below:

1. Avoidance or minimization of injury or death of marine mammals wherever possible (goals 2, 3, and 4 may contribute to this goal).

2. A reduction in the numbers of marine mammals (total number or number at biologically important time or location) exposed to received levels of noises generated from exploration drilling and associated activities, or other activities expected to result in the take of marine mammals (this goal may contribute to 1, above, or to reducing harassment takes only).

3. A reduction in the number of times (total number or number at biologically important time or location) individuals would be exposed to received levels of noises generated from exploration drilling and associated activities, or other activities expected to result in the take of marine mammals (this goal may contribute to 1, above, or to reducing harassment takes only).

4. A reduction in the intensity of exposures (either total number or number at biologically important time or location) to received levels of noises generated from exploration drilling and associated activities, or other activities expected to result in the take of marine mammals (this goal may contribute to a, above, or to reducing the severity of harassment takes only).

5. Avoidance or minimization of adverse effects to marine mammal habitat, paying special attention to the food base, activities that block or limit passage to or from biologically important areas, permanent destruction of habitat, or temporary destruction/disturbance of habitat during a biologically important time.

6. For monitoring directly related to mitigation—an increase in the probability of detecting marine mammals, thus allowing for more effective implementation of the mitigation.

Based on our evaluation of the applicant's mitigation measures, as well as other measures considered by NMFS, NMFS has determined that the prescribed mitigation measures provide the means of effecting the least practicable impact on marine mammals species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance. Mitigation to effect least practicable impact on the availability of marine mammals for taking for subsistence uses is discussed later in this document (see “

Impact on Availability of Affected Species or Stock

for Taking for Subsistence Uses

” section).

Monitoring and Reporting

In order to issue an ITA for an activity, section 101(a)(5)(D) of the MMPA states that NMFS must, where applicable, 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 ITAs 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. The change made from the proposed notice for the IHA is that Shell revised the deployment design of its acoustic arrays for passive acoustic monitoring based on recommendations from the peer-review panel. This is discussed in detail in the “

Monitoring Plan Peer Review

” section below.

Monitoring measures prescribed by NMFS should accomplish one or more of the following general goals:

1. An increase in the probability of detecting marine mammals, both within the mitigation zone (thus allowing for more effective implementation of the mitigation) and in general to generate more data to contribute to the analyses mentioned below;

2. An increase in our understanding of how many marine mammals are likely to be exposed to levels of noises generated from exploration drilling and associated activities that we associate with specific adverse effects, such as behavioral harassment, TTS, or PTS;

3. An increase in our understanding of how marine mammals respond to stimuli expected to result in take and how anticipated adverse effects on individuals (in different ways and to varying degrees) may impact the population, species, or stock (specifically through effects on annual rates of recruitment or survival) through any of the following methods:

Behavioral observations in the presence of stimuli compared to observations in the absence of stimuli (need to be able to accurately predict received level, distance from source, and other pertinent information);

Physiological measurements in the presence of stimuli compared to observations in the absence of stimuli (need to be able to accurately predict received level, distance from source, and other pertinent information);

Distribution and/or abundance comparisons in times or areas with concentrated stimuli versus times or areas without stimuli;

4. An increased knowledge of the affected species; and

5. An increase in our understanding of the effectiveness of certain mitigation and monitoring measures.

NMFS believes that the required measures will contribute towards these goals.

Monitoring Measures

1. Protected Species Observers

Vessel based monitoring for marine mammals will be done by trained PSOs on both drilling units and ice management and anchor handler vessels throughout the exploration drilling activities. The observers will monitor the occurrence and behavior of marine mammals near the drilling units, ice management and anchor handling vessels, during all daylight periods during the exploration drilling operation, and during most periods when exploration drilling is not being conducted. PSO duties will include watching for and identifying marine mammals; recording their numbers, distances, and reactions to the exploration drilling activities; and documenting exposures to sound levels that may constitute harassment. PSOs also will help ensure that the vessel communicates with the Communications and Call Centers (Com Centers) in Native villages along the Chukchi Sea coast.

(A) Number of Observers

A sufficient number of PSOs will be onboard to meet the following criteria:

• 100 percent monitoring coverage during all periods of exploration drilling operations in daylight;

• Maximum of four consecutive hours on watch per PSO; and

• Maximum of approximately 12 hours on watch per day per PSO.

PSO teams will consist of trained Alaska Natives and field biologist observers. An experienced field crew leader will be on every PSO team aboard the drilling units, ice management and anchor handling vessels, and other support vessels during the exploration drilling program. The total number of PSOs aboard may decrease later in the season as the duration of daylight decreases.

(B) Crew Rotation

Shell anticipates that there will be provisions for crew rotation at least every three to six weeks to avoid observer fatigue. During crew rotations detailed notes will be provided to the incoming crew leader. Other communications such as email, fax, and/or phone communication between the current and oncoming crew leaders during each rotation will also occur when necessary. In the event of an unexpected crew change Shell will facilitate such communications to insure monitoring consistency among shifts.

(C) Observer Qualifications and Training

Crew leaders serving as PSOs will have experience from one or more projects with operators in Alaska or the Canadian Beaufort.

Crew leaders will be highly experienced with previous vessel based marine mammal monitoring projects. Resumes for those individuals will be provided to the NMFS for approval. All PSOs will be trained and familiar with the marine mammals of the area. A PSO handbook, adapted for the specifics of the planned Shell drilling program, will be prepared and distributed beforehand to all PSOs.

PSOs will also complete a two-day training and refresher session on marine mammal monitoring, to be conducted shortly before the anticipated start of the drilling season. The training sessions will be conducted by marine mammalogists with extensive crew leader experience from previous vessel based seismic monitoring programs in the Arctic.

Primary objectives of the training include:

• Review of the 4MP for this project, including any amendments adopted or specified by NMFS in the final IHA or other agreements in which Shell may elect to participate;

• Review of marine mammal sighting, identification, (photographs and videos) and distance estimation methods, including any amendments specified by NMFS in the IHA;

• Review operation of specialized equipment (

e.g.,

reticle binoculars, big eye binoculars, night vision devices, GPS system); and

• Review of data recording and data entry systems, including procedures for recording data on mammal sightings, exploration drilling and monitoring activities, environmental conditions, and entry error control. These procedures will be implemented through use of a customized computer databases and laptop computers.

(D) PSO Handbook

A PSO Handbook will be prepared for Shell's monitoring program. The Handbook will contain maps, illustrations, and photographs as well as copies of important documents and

descriptive text and are intended to provide guidance and reference information to trained individuals who will participate as PSOs. The following topics will be covered in the PSO Handbook:

• Summary overview descriptions of the project, marine mammals and underwater sound energy, the 4MP (vessel-based, aerial, acoustic measurements, special studies), the IHA and other regulations/permits/agencies, the Marine Mammal Protection Act;

• Monitoring and mitigation objectives and procedures, including initial exclusion and disturbance zones;

• Responsibilities of staff and crew regarding the 4MP;

• Instructions for staff and crew regarding the 4MP;

• Data recording procedures: Codes and coding instructions, common coding mistakes, electronic database; navigational, marine physical, and drilling data recording, field data sheet;

• Use of specialized field equipment (

e.g.,

reticle binoculars, Big-eye binoculars, NVDs, laser rangefinders);

• Reticle binocular distance scale;

• Table of wind speed, Beaufort wind force, and sea state codes;

• Data storage and backup procedures;

• List of species that might be encountered: Identification, natural history;

• Safety precautions while onboard;

• Crew and/or personnel discord; conflict resolution among PSOs and crew;

• Drug and alcohol policy and testing;

• Scheduling of cruises and watches;

• Communications;

• List of field gear provided;

• Suggested list of personal items to pack;

• Suggested literature, or literature cited;

• Field reporting requirements and procedures;

• Copies of the IHA will be made available; and

• Areas where vessels need permission to operate such as the Ledyard Bay Critical Habitat Unit (LBCHU).

2. Vessel-Based Monitoring Methodology

The observer(s) will watch for marine mammals from the best available vantage point on the drilling units and support vessels 30 minutes before and during Shell's activities, and for 30 minutes after the activities are ceased. Ideally this vantage point is an elevated stable platform from which the PSO has an unobstructed 360° view of the water. The observer(s) will scan systematically with the naked eye and 7 x 50 reticle binoculars, supplemented with Big-eye binoculars and night-vision equipment when needed. Personnel on the bridge will assist the marine mammal observer(s) in watching for pinnipeds and cetaceans. New or inexperienced PSOs will be paired with an experienced PSO or experienced field biologist so that the quality of marine mammal observations and data recording is kept consistent.

Information to be recorded by marine mammal observers will include the same types of information that were recorded during previous monitoring projects (

e.g.,

Moulton and Lawson 2002; Reiser

et al.

2010, 2011; Bisson

et al.

2013). When a mammal sighting is made, the following information about the sighting will be carefully and accurately recorded:

• Species, group size, age/size/sex categories (if determinable), physical description of features that were observed or determined not to be present in the case of unknown or unidentified animals;

• Behavior when first sighted and after initial sighting;

• Heading (if consistent), bearing and distance from observer;

• Apparent reaction to activities (

e.g.,

none, avoidance, approach, paralleling, etc.), closest point of approach, and behavioral pace;

• Time, location, speed, and activity of the vessel, sea state, ice cover, visibility, and sun glare, on support vessels the distance and bearing to the drilling unit will also be recorded; and

• Positions of other vessel(s) in the vicinity of the observer location.

The vessel's position, speed, water depth, sea state, ice cover, visibility, and sun glare will also be recorded at the start and end of each observation watch, every 30 minutes during a watch, and whenever there is a change in any of those variables.

Distances to nearby marine mammals will be estimated with binoculars (Fujinon 7 x 50 binoculars) containing a reticle to measure the vertical angle of the line of sight to the animal relative to the horizon.

An electronic database will be used to record and collate data obtained from visual observations during the vessel-based study. The PSOs will enter the data into the custom data entry program installed on field laptops. The data entry program automates the data entry process and reduces data entry errors and maximizes PSO time spent looking at the water. PSOs also have voice recorders available to them. This is another tool that will allow PSOs to maximize time spent focused on the water.

PSOs will be instructed to identify animals as unknown when appropriate rather than strive to identify an animal when there is significant uncertainty. PSOs should also provide any sightings cues they used and any distinguishable features of the animal even if they are not able to identify the animal and record it as unidentified. Emphasis will also be placed on recording what was not seen, such as dorsal features.

(A) Monitoring at Night and in Poor Visibility

Night-vision equipment “Generation 3” binocular image intensifiers or equivalent units will be available for use when needed. However, past experience with night-vision devices in the Beaufort Sea and elsewhere indicates they are not nearly as effective as visual observation during daylight hours (

e.g.,

Harris

et al.

1997, 1998; Moulton and Lawson 2002; Hartin

et al.

2013).

(B) Specialized Field Equipment

Shell will provide the following specialized field equipment for use by the onboard PSOs: Reticle binoculars, Big-eye binoculars, GPS unit, laptop computers, night vision binoculars, and possibly digital still and digital video cameras. Big eye binoculars will be mounted and used on key monitoring vessels including the drilling units, ice management vessels and the anchor handler.

(C) Field Data-Recording, Verification, Handling, and Security

The observers on the drilling units and support vessels will record their observations directly into computers using a custom software package. The accuracy of the data entry will be verified in the field by computerized validity checks as the data are entered, and by subsequent manual checking. These procedures will allow initial summaries of data to be prepared during and shortly after the field season, and will facilitate transfer of the data to statistical, graphical or other programs for further processing. Quality control of the data will be facilitated by (1) the start-of-season training session, (2) subsequent supervision by the onboard field crew leader, and (3) ongoing data checks during the field season.

The data will be sent off of the vessel to Anchorage on a daily basis and backed up regularly onto storage devices on the vessel, and stored at separate locations on the vessel. If practicable, hand-written data sheets will be photocopied daily during the field

season. Data will be secured further by having data sheets and backup data devices carried back to the Anchorage office during crew rotations.

PSOs will be able to plot sightings in near real-time for their vessel. Significant sightings from key vessels including drilling units, ice management, anchor handlers and aircraft will be relayed between platforms to keep observers aware of animals that may be in or near the area but may not be visible to the observer at any one time. Emphasis will be placed on relaying sightings with the greatest potential to involve mitigation or reconsideration of a vessel's course (

e.g.,

large group of bowheads).

Observer training will emphasize the use of “comments” for sightings that may be considered unique or not fully captured by standard data codes. In addition to the standard marine mammal sightings forms, a specialized form was developed for recording traditional knowledge and natural history observations. PSOs will be encouraged to use this form to capture observations related to any aspect of the arctic environment and the marine mammals found within it. Examples might include relationships between ice and marine mammal sightings, marine mammal behaviors, comparisons of observations among different years/seasons, etc. Voice recorders will also be available for observers to use during periods when large numbers of animals may be present and it is difficult to capture all of the sightings on written or digital forms. These recorders can also be used to capture traditional knowledge and natural history observations should individuals feel more comfortable using the recorders rather than writing down their comments. Copies of these records will be available to all observers for reference if they wish to prepare a statement about their observations for reporting purposes. If prepared, this statement would be included in the 90-day and final reports documenting the monitoring work.

3. Acoustic Monitoring Plan

Exploration Drilling, ZVSP, and Vessel Noise Measurements

Exploration drilling sounds are expected to vary significantly with time due to variations in the level of operations and the different types of equipment used at different times onboard the drilling units. The goals of these measurements are:

• To quantify the absolute sound levels produced by exploration drilling and to monitor their variations with time, distance and direction from the drilling unit;

• To measure the sound levels produced by vessels while operating in direct support of exploration drilling operations. These vessels will include crew change vessels, tugs, ice-management vessels, and spill response vessels not measured in 2012; and

• To measure the sound levels produced by an end-of-hole zero-offset vertical seismic profile (ZVSP) survey using a stationary sound source.

Sound characterization and measurements of all exploration drilling activities will be performed using two sets of six parallel Autonomous Multichannel Acoustic Recorders (AMAR) deployed on the seabed along the distances of 0.5, 1, 2, 4, 8 and 16 mi from each drilling unit. All 12 recording stations will sample at least at 32 kHz, providing calibrated acoustic measurements in the 5 Hz to 16 kHz frequency band. The logarithmic spacing of the recorders is designed to sample the attenuation of drilling unit sounds with distance, and also provide information on potential marine mammal displacement. The autonomous recorders will sample through completion of the first well, to provide a detailed record of sounds emitted from all activities. These recorders will be retrieved and their data analyzed and reported in the project's 90-day report.

The deployment of drilling sound monitoring equipment will occur before, or as soon as possible after the

Discoverer

and the

Polar Pioneer

are on site. Activity logs of exploration drilling operations and nearby vessel activities will be maintained to correlate with these acoustic measurements. All results, including back-propagated source levels for each operation, will be reported in the 90-day report.

(A) Vessel Sound Characterization

Vessel sound characterizations will be performed using dedicated recorders deployed at sufficient distances from exploration drilling operations so that sound produced by those activities does not interfere. Three AMAR acoustic recorders will be deployed on and perpendicular to a sail track on which all Shell contracted vessels will transit. This geometry is designed to obtain sound level measurements as a function of distance and direction. The fore and aft directions are sampled continuously over longer distances to 3 and 6 miles (5 and 10 km) respectively, while broadside and other directions are sampled as the vessels pass closer to the recorders.

Vessel sound measurements will be processed and reported in a manner similar to that used by Shell and other operators in the Beaufort and Chukchi Seas during seismic survey operations. The measurements will further be analyzed to calculate source levels. Source directivity effects will be examined and reported. The measurements will include sound level data but not source level calculations. All vessel characterization results, including source levels, will be reported in

1/3

-octave bands in the project 90-day report.

(B) Zero-Offset Vertical Seismic Profiling Sound Monitoring

Shell may conduct ZVSP at two drill sites in 2015. See the

Federal Register

Notice of proposed IHA for information on this activity.

ZVSP sound verification measurements will be performed using either the AMARs that are deployed for drilling unit sound characterizations, or by JASCO Ocean Bottom Hydrophone (OBH) recorders. The AMARs will not be retrieved until several days after the ZVSP as they are intended to monitor during retrievals of drilling unit anchors and related support activities.

(C) Acoustic Data Analyses

Exploration drilling sound data will be analyzed to extract a record of the frequency-dependent sound levels as a function of time. These results are useful for correlating measured sound energy events with specific survey operations. The analysis provides absolute sound levels in finite frequency bands that can be tailored to match the highest-sensitivity hearing ranges for species of interest. The analyses will also consider sound level integrated through 1-hour durations (referred to as sound energy equivalent level Leq (1-hour). Similar graphs for long time periods will be generated as part of the data analysis performed for indicating drilling sound variation with time in selected frequency bands.

(D) Reporting of Results

Acoustic sound level results will be reported in the 90-day and comprehensive reports for this program. The results reported will include:

• Sound source levels for the drilling units and all drilling support vessels;

• Spectrogram and band level versus time plots computed from the continuous recordings obtained from the hydrophone systems;

• Hourly Leq levels at the hydrophone locations; and

• Correlation of exploration drilling source levels with the type of

exploration drilling operation being performed. These results will be obtained by observing differences in drilling sound associated with differences in drilling unit activities as indicated in detailed drilling unit logs.

Acoustic “Net” Array in Chukchi Sea

This section describes acoustic studies that were undertaken from 2006 through 2013 in the Chukchi Sea as part of the Joint Monitoring Program and that will be continued by Shell during exploration drilling activities. The acoustic “net” array used during the 2006-2013 field seasons in the Chukchi Sea was designed to accomplish two main objectives. The first was to collect information on the occurrence and distribution of marine mammals (including beluga whale, bowhead whale, and other species) that may be available to subsistence hunters near villages along the Chukchi Sea coast and to document their relative abundance, habitat use, and migratory patterns. The second objective was to measure the ambient soundscape throughout the eastern Chukchi Sea and to record received levels of sounds from industry and other activities further offshore in the Chukchi Sea.

A net array configuration similar to that deployed in 2007-2013 is again proposed. The basic components of this effort consist of autonomous acoustic recorders deployed widely across the U.S. Chukchi Sea during the open water season and then more limited arrays during the winter season. These calibrated systems sample at 16 kHz with 24-bit resolution, and are capable of recording marine mammal sounds and making anthropogenic noise measurements. The net array configuration will include a regional array of 23 AMAR recorders deployed July-October off the four main transect locations: Cape Lisburne, Point Lay, Wainwright and Barrow. All of these offshore systems will capture sounds associated with exploration drilling, where present, over large distances to help characterize the sound transmission properties in the Chukchi Sea. Six additional summer AMAR recorders will be deployed around the Burger drill sites to monitor directional variations and longer-range propagation of drilling-related sounds. These recorders will also be used to examine marine mammal vocalization patterns in the vicinity of exploration drilling activities. The regional recorders will be retrieved in early October 2015; acoustic monitoring will continue through the winter with 8 AMAR recorders deployed October 2015-August 2016. The winter recorders will sample at 16 kHz on a 17% duty cycle (40 minutes every 4 hours). The winter recorders deployed in previous years have provided important information about fall and spring migrations of bowhead, beluga, walrus and several seal species.

The Chukchi acoustic net array will produce an extremely large dataset comprising several Terabytes of acoustic data. The analyses of these data require identification of marine mammal vocalizations. Because of the very large amount of data to be processed, the analysis methods will incorporate automated vocalization detection algorithms that have been developed over several years. While the hydrophones used in the net array are not directional, and therefore not capable of accurate localization of detections, the number of vocalizations detected on each of the sensors provides a measure of the relative spatial distribution of some marine mammal species, assuming that vocalization patterns are consistent within a species across the spatial and geographic distribution of the hydrophone array. These results therefore provide information such as timing of migrations and routes of migration for belugas and bowheads.

A second purpose of the Chukchi net array is to monitor the amplitude of exploration drilling sound propagation over a very large area. It is expected that sounds from exploratory drilling activities will be detectable on hydrophone systems within approximately 30 km of the drilling units when ambient sound energy conditions are low. The drilling sound levels at recorder locations will be quantified and reported.

Analysis of all acoustic data will be prioritized to address the primary questions. The primary data analysis questions are to (a) determine when, where, and what species of animals are acoustically detected on each recorder (b) analyze data as a whole to determine offshore distributions as a function of time, (c) quantify spatial and temporal variability in the ambient sound energy, and (d) measure received levels of exploration drilling survey events and drilling unit activities. The detection data will be used to develop spatial and temporal animal detection distributions. Statistical analyses will be used to test for changes in animal detections and distributions as a function of different variables (

e.g.,

time of day, season, environmental conditions, ambient sound energy, and drilling or vessel sound levels).

4. Chukchi Offshore Aerial Photographic Monitoring Program

Shell has been reticent to conduct manned aerial surveys in the offshore Chukchi Sea because conducting those surveys puts people at risk. There is a strong desire, however, to obtain data on marine mammal distribution in the offshore Chukchi Sea and Shell will conduct a photographic aerial survey that would put fewer people at risk as an alternative to the fully-manned aerial survey. The photographic survey would reduce the number of people on board the aircraft from six persons to two persons (the pilot and copilot) and would serve as a pilot study for future surveys that would use an Unmanned Aerial System (UAS) to capture the imagery.

Aerial photographic surveys have been used to monitor distribution and estimate densities of marine mammals in offshore areas since the mid-1980s, and before that, were used to estimate numbers of animals in large concentration areas. Digital photographs provide many advantages over observations made by people if the imagery has sufficient resolution (Koski

et al.

2013). With photographs there is constant detectability across the imagery, whereas observations by people decline with distance from the center line of the survey area. Observations at the outer limits of the transect can decline to 5-10% of the animals present for real-time observations by people during an aerial survey. The distance from the trackline of sightings is more accurately determined from photographs; group size can be more accurately determined; and sizes of animals can be measured, and hence much more accurately determined, in photographs. As a result of the latter capability, the presence or absence of a calf can be more accurately determined from a photograph than by in-the-moment visual observations. Another benefit of photographs over visual observations is that photographs can be reviewed by more than one independent observer allowing quantification of detection, identification and group size biases.

The proposed photographic survey will provide imagery that can be used to evaluate the ability of future studies to use the same image capturing systems in an UAS where people would not be put at risk. Although the two platforms are not the same, the slower airspeed and potentially lower flight altitude of the UAS would mean that the data quality would be better from the UAS. Initial comparisons have been made between data collected by human observers on

board both the Chukchi and Beaufort aerial survey aircraft and the digital imagery collected in 2012. Overall, the imagery provided better estimates of the number of large cetaceans and pinnipeds present but fewer sightings were identified to species in the imagery than by PSOs, because the PSOs had sightings in view for a longer period of time and could use behavior to differentiate species. The comparisons indicated that some cetaceans that were not seen by PSOs were detected in the imagery; errors in identification were made by the PSOs during the survey that could be resolved from examination of the imagery; cetaceans seen by PSOs were visible in the imagery; and during periods with large numbers of sightings, the imagery provided much better estimates of numbers of sightings and group size than the PSO data.

Photographic surveys would start as soon as the ice management, anchor handler and drilling units are at or near the first drill site and would continue throughout the drilling period and until the drilling related vessels have left the exploration drilling area. Since the current plans are for vessels to enter the Chukchi Sea on or about 1 July, surveys would be initiated on or about 3 July. This start date differs from past practices of beginning five days prior to initiation of an activity and continuing until five days after cessation of the activity because the presence of vessels with helidecks in the area where overflights will occur is one of the main mitigations that will allow for safe operation of the overflight program this far offshore. The surveys will be based out of Barrow and the same aircraft will conduct the offshore surveys around the drilling units and the coastal saw-tooth pattern. The surveys of offshore areas around the drilling units will take precedence over the sawtooth survey, but if weather does not permit surveying offshore, the nearshore survey will be conducted if weather permits.

The aerial survey grids are designed to maximize coverage of the sound level fields of the drilling units during the different exploratory drilling activities. The survey grids can be modified as necessary based on weather and whether a noisy activity or quiet activity is taking place. The intensive survey design maximizes the effort over the area where sound levels are highest. The outer survey grid covers an elliptical area with a 45 km radius near the center of the ellipse. The spacing of the outer survey lines is 10 km, and the spacing between the intensive and outer lines is 5 km. The expanded survey grid covers a larger survey area, and the design is based on an elliptical area with a 50 km radius centered on the well sties. For both survey designs the main transects will be spaced 10 km apart which will allow even coverage of the survey area during a single flight if weather conditions permit completion of a survey. A random starting point will be selected for each survey and the evenly spaced lines will be shifted NE. or SW. along the perimeter of the elliptical survey area based on the start point. The total length of survey lines will be about 1,000 km and the exact length will depend on the location of the randomly selected start point.

Following each survey, the imagery will be downloaded from the memory card to a portable hard drive and then backed up on a second hard drive and stored at accommodations in Barrow until the second hard drive can be transferred to Anchorage. In Anchorage, the imagery will be processed through a computer-assisted analysis program to identify where marine mammal sightings might be located among the many images obtained. A team of trained photo analysts will review the photographs identified as having potential sightings and record the appropriate data on each sighting. If time permits, a second review of some of the images will be conducted while in the field, but the sightings recorded during the second pass will be identified in the database as secondary sightings, so that biases associated with the detection in the imagery can be quantified. If time does not permit that review to be conducted while in the field, the review will be conducted by personnel in the office during or after the field season. A sample of images that are not identified by the computer-assisted analysis program will be examined in detail by the image analysts to determine if the program has missed marine mammal sightings. If the analysis program has missed mammal sightings, these data will be to develop correction factors to account for these missed sightings among the images that were not examined.

5. Chukchi Sea Coastal Aerial Survey

Nearshore aerial surveys of marine mammals in the Chukchi Sea were conducted over coastal areas to approximately 23 miles (mi) [37 kilometers (km)] offshore in 2006-2008 and in 2010 in support of Shell's summer seismic exploration activities. In 2012 these surveys were flown when it was not possible to fly the photographic transects out over the Burger well site due to weather or rescue craft availability. These surveys provided data on the distribution and abundance of marine mammals in nearshore waters of the Chukchi Sea. Shell plans to conduct these nearshore aerial surveys in the Chukchi Sea as opportunities unfold and surveys will be similar to those conducted during previous years except that no PSOs will be onboard the aircraft. As noted above, the first priority will be to conduct photographic surveys around the offshore exploration drilling activities, but nearshore surveys will be conducted whenever weather does not permit flying offshore. As in past years, surveys in the southern part of the nearshore survey area will depend on the end of the beluga hunt near Point Lay. In past years, Point Lay has requested that aerial surveys not be conducted until after the beluga hunt has ended and so the start of surveys has been delayed until mid-July.

Alaskan Natives from villages along the east coast of the Chukchi Sea hunt marine mammals during the summer and Native communities are concerned that offshore oil and gas exploration activities may negatively impact their ability to harvest marine mammals. Of particular concern are potential impacts on the beluga harvest at Point Lay and on future bowhead harvests at Point Hope, Point Lay, Wainwright and Barrow. Other species of concern in the Chukchi Sea include the gray whale; bearded, ringed, and spotted seals. Gray whale and harbor porpoise are expected to be the most numerous cetacean species encountered during the proposed aerial survey; although harbor porpoise are abundant they are difficult to detect from aircraft because of their small size and brief surfacing. Beluga whales may occur in high numbers early in the season. The ringed seal is likely to be the most abundant pinniped species. The current aerial survey program will be designed to collect distribution data on cetaceans but will be limited in its ability to collect similar data on pinnipeds and harbor porpoises because they are not reliably detectable during review of the collected images unless a third camera with a 50 mm or similar lens is deployed.

Transects will be flown in a saw-toothed pattern between the shore and 23 mi (37 km) offshore as well as along the coast from Point Barrow to Point Hope. This design will permit completion of the survey in one to two days and will provide representative coverage of the nearshore region. Sawtooth transects were designed by placing transect start/end points every 34 mi (55 km) along the offshore boundary of this 23 mi (37 km) wide nearshore zone, and at midpoints between those points along the coast. The transect line start/end points will

be shifted along both the coast and the offshore boundary for each survey based upon a randomized starting location, but overall survey distance will not vary substantially. The coastline transect will simply follow the coastline or barrier islands. As with past surveys of the Chukchi Sea coast, coordination with coastal villages to avoid disturbance of the beluga whale subsistence hunt will be extremely important. “No-fly” zones around coastal villages or other hunting areas established during communications with village representatives will be in place until the end of the hunting season.

Standard aerial survey procedures used in previous marine mammal projects (by Shell as well as by others) will be followed. This will facilitate comparisons and (as appropriate) pooling with other data, and will minimize controversy about the chosen survey procedures. The aircraft will be flown at 110-120 knots ground speed and usually at an altitude of 1,000 ft (305 m). Aerial surveys at an altitude of 1,000 ft (305 m) do not provide much information about seals but are suitable for bowhead, beluga, and gray whales. The need for a 1,000+ ft (305+ m) or 1,500+ ft (454+ m) cloud ceiling will limit the dates and times when surveys can be flown. Selection of a higher altitude for surveys would result in a significant reduction in the number of days during which surveys would be possible, impairing the ability of the aerial program to meet its objectives.

The surveyed area will include waters where belugas are usually available to subsistence hunters. If large concentrations of belugas are encountered during the survey, the aircraft will climb to ~10,000 ft (3,050 m) altitude to avoid disturbing the cetaceans. If cetaceans are in offshore areas, the aircraft will climb high enough to include all cetaceans within a single photograph; typically about 3,000 ft (914 m) altitude. When in shallow water, belugas and other marine mammals are more sensitive to aircraft over flights and other forms of disturbance than when they are offshore (see Richardson

et al.

1995 for a review). They frequently leave shallow estuaries when over flown at altitudes of 2,000-3,000 ft (610-904 m); whereas they rarely react to aircraft at 1,500 ft (457 m) when offshore in deeper water.

Monitoring Plan Peer Review

The MMPA requires that monitoring plans be independently peer reviewed “where the proposed activity may affect the availability of a species or stock for taking for subsistence uses” (16 U.S.C. 1371(a)(5)(D)(ii)(III)). NMFS' implementing regulations state, “Upon receipt of a complete monitoring plan, and at its discretion, [NMFS] will either submit the plan to members of a peer review panel for review or within 60 days of receipt of the proposed monitoring plan, schedule a workshop to review the plan” (50 CFR 216.108(d)).

NMFS established an independent peer review panel to review Shell's 4MP for the proposed exploration drilling in the Chukchi Sea. The panel met in early March 2015, and provided comments and recommendations to NMFS in April 2015. The full panel report can be viewed on the Internet at:

http://www.nmfs.noaa.gov/pr/permits/incidental.htm

.

NMFS provided the panel with Shell's IHA application and monitoring plan and asked the panel to answer the following questions:

1. Will the applicant's stated objectives effectively further the understanding of the impacts of their activities on marine mammals and otherwise accomplish the goals stated above? If not, how should the objectives be modified to better accomplish the goals above?

2. Can the applicant achieve the stated objectives based on the methods described in the plan?

3. Are there technical modifications to the proposed monitoring techniques and methodologies proposed by the applicant that should be considered to better accomplish their stated objectives?

4. Are there techniques not proposed by the applicant (

i.e.,

additional monitoring techniques or methodologies) that should be considered for inclusion in the applicant's monitoring program to better accomplish their stated objectives?

5. What is the best way for an applicant to present their data and results (formatting, metrics, graphics, etc.) in the required reports that are to be submitted to NMFS (

i.e.,

90-day report and comprehensive report)?

The peer-review panel report contains recommendations that the panel members felt were applicable to the Shell' monitoring plans. The panel concluded that the proposed exclusion zones, PSO vessel-based and aerial effort described in the 4MP will further the understanding of the impacts of the activities on marine mammals. However, the panel also pointed out that Shell's passive acoustics monitoring objectives did not include monitoring for negative effects of drilling activities such as spatial displacement. In addition, the panel concluded that the methodology described in the 4MP would only cover the stated objectives during good visibility day-light operations, where visual effort is most efficient. To compensate for these issues, the panel recommended Shell modify the deployment configuration of passive acoustic sensors to allow proper evaluation of evaluating the potential for spatial displacement of marine mammals. The panel provided two options:

Option A: Involves 4 axial deployment lines to independently evaluate effects of each drilling site; and

Option B: Involves 3 axial deployment lines but reduces the capacity to tease effects from each drilling site.

In addition, the panel recommended that the aerial survey transect lines be oriented parallel to the acoustic arrays and/or the axis between the two drill sites for compatibility with acoustic data.

Furthermore, the panel also provided comments on reporting measures and requests that the 90-day monitoring report include sightability curves for each species observed in the study area, and to report concurrent collection of spatially overlapped visual and acoustic data to allow for a more detailed description of approximate acoustic detection ranges for the different species sighted and acoustically detected.

NMFS discussed these recommendations with Shell to improve its monitoring and reporting measures. As a result, Shell considered localizing arrays of the types proposed by the peer review panel when designing its original passive acoustic monitoring plan. That analysis generated predicted detection ranges for marine mammal calls in the presence of support vessel and drilling activity sounds. It was found that detection ranges would be small (often less than 2 km) in the presence of the expected sound levels within a few kilometers of the drill sites. The panel's suggested recorder spacing is 5 km, so the effectiveness of the array would be limited. The layout of recorders close to the drilling sites as originally proposed was designed to focus on quantifying drilling source levels and ZVSP sound levels as a function of distance away from the drill sites.

Even though its localizing abilities might be limited, especially with respect to being able to examine deflections, the approximate geometry of part of the Panel's Option A can be achieved by simply reorienting Shell's drill rig sound characterization arrays. Shell therefore modified the initial layout to approximate the panel's Option A array layout.

For recommendations concerning reporting measures, Shell agrees to provide:

(1) Sightability curves by species or species group in the 90-day report, as appropriate given the data collected, and

(2) Visual and acoustic detection results overlaid in the 90-day report to the extent allowed by data collected in 2015.

Concerning the comment on orienting aerial transect lines parallel to the acoustic arrays and/or the axis between the two drill sites for compatibility with acoustic data, Shell determined that a north-south orientation that would be perpendicular to the generally east-west migration of bowheads may be advantageous to generating statistically robust density estimates. The original northwest-southeast orientation was designed to be consistent with the ASAMM survey lines that cover the greater region.

Since the Burger aerial survey does not tie-back to the coastline, maintaining consistency with the ASAMM survey lines is less useful than orienting the lines to be perpendicular with the migration of bowheads. Therefore, Shell is considering shifting the orientation of the survey lines to be north-south. However, for safety reasons, further analysis of the overall flight time and duration of time spent on the western edge of the survey area using the north-south survey lines must be completed before the orientation and location of the lines can be finalized. Shell states that it must assess the specifics of flight times, aviation fuel requirements, and distances for which search and rescue (SAR) coverage exists, among other factors before committing to a change in the flight pattern and flight duration.

This text is long and has been trimmed here. Open the source document for the complete record.