Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Seismic Surveys in Cook Inlet, Alaska

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 140912776-6553-02]

RIN 0648-BE53

Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to Seismic Surveys in Cook Inlet, Alaska

AGENCY:

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

ACTION:

Final rule.

SUMMARY:

NMFS is issuing regulations governing related Letters of Authorization (LOAs) in response to a request from Apache Alaska Corporation (Apache) for authorization to take marine mammals, by harassment, incidental to its oil and gas exploration seismic survey program in Cook Inlet, Alaska. This action will put the applicant into compliance with the Marine Mammal Protection Act (MMPA) and minimize impacts to marine mammals in Cook Inlet.

DATES:

Effective August 19, 2016 through July 20, 2021.

ADDRESSES:

An electronic copy of the application, containing a list of references used in this document, and the associated Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) may be obtained by writing to the address specified above, 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 above address.

FOR FURTHER INFORMATION CONTACT:

Sara Young, Office of Protected Resources, NMFS, (301) 427-8484.

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.

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 July 11, 2014, NMFS received a complete application from Apache requesting authorization for the take of nine marine mammal species incidental to an oil and gas exploration seismic program in Cook Inlet, AK, over the course of 5 years. On February 23, 2015, NMFS published a notice in the

Federal Register

of our proposal to issue regulations and subsequent LOAs with preliminary determinations (80 FR 9510). The filing of the notice initiated a 30-day public comment period, which was then extended by 15 days. The comments and our responses are discussed later in this document.

The activity will occur for approximately 8-9 months annually over the course of a 5-year period between August 2016 and July 2021. In-water airguns will be active for approximately 2-3 hours during each of the slack tide periods. There are approximately four slack tide periods in a 24-hour period; therefore, airgun operations will be active during approximately 8-12 hours per day, if weather conditions allow. The following specific aspects of the activity are likely to result in the take of marine mammals: seismic airgun operations. Take, by Level B Harassment only, of individuals of nine species or stocks of marine mammals is anticipated to result from the specified activity.

Description of the Specified Activity

Overview

Apache has acquired over 850,000 acres of oil and gas leases in Cook Inlet since 2010 with the primary objective to explore for and develop oil and gas resources in Cook Inlet. Apache will conduct oil and gas seismic surveys in Cook Inlet, Alaska, in an area that encompasses approximately 5,684 km

2

(2,195 mi

2

) of intertidal and offshore areas. This area is slightly larger than that shown in Apache's MMPA application and corresponds with the request contained in their Biological Assessment and Figure 1 in this document, which is also available at:

http://www.nmfs.noaa.gov/pr/permits/incidental/oilgas.htm#apache2020.

Vessels will lay and retrieve nodal sensors on the sea floor in periods of low current, or, in the case of the intertidal area, during high tide over a 24-hour period. In deep water, a hull or pole mounted pinger system will be used to determine the exact location of the nodes. The two instruments used in this technique are a transceiver (operating at 33-55kHz with a maximum source level of 188 dB re 1 µPa at 1 meter) and a transponder (operating at 35-50kHz with a maximum source level of 188 dB re 1 µPa at 1 meter). The majority of the sound energy produced by this project is from the seismic airgun array, for which Apache will use two synchronized vessels. Each source vessel will be equipped with compressors and 2,400 cubic inch (in

3

) airgun arrays. Additionally, one of the source vessels will be equipped with a 440 in

3

shallow water source array, which can be deployed at high tide in the intertidal area in less than 1.8 m (6 ft) of water. The two source vessels do not fire the airguns simultaneously; rather, each vessel fires a shot every 24 seconds, leaving 12 seconds between shots.

The operation will utilize two source vessels, three cable/nodal deployment and retrieval operations vessels, a mitigation/monitoring vessel, a node re-charging and housing vessel, and two small vessels for personnel transport and node support in the extremely shallow waters in the intertidal area. Water depths for the program will range from 1-128 m (0-420 ft).

Seismic surveys are designed to collect bathymetric and sub-seafloor data that allow the evaluation of potential shallow faults, gas zones, and archeological features at prospective

exploration drilling locations. In the spring of 2011, Apache conducted a seismic test program to evaluate the feasibility of using new nodal (no cables) technology seismic recording equipment for operations in Cook Inlet. This test program found and provided important input to assist in finalizing the design of the 3D seismic program in Cook Inlet (the nodal technology was determined to be feasible).

Apache began seismic onshore acquisition on the west side of Cook Inlet in September 2011 and offshore acquisition in May 2012 under an Incidental Harrassent Authorization (IHA) issued by NMFS for April 30, 2012, through April 30, 2013 (77 FR 27720, May 11, 2012). Apache continued seismic data acquisition for approximately 3 months in spring and summer 2014 in compliance with an IHA issued on March 4, 2014 (79 FR 13626, March 11, 2014). Apache reported a total of 29 level B harassment exposures from the 2014 IHA comprising beluga whales, humpback whales, harbor seals, and harbor porpoises, which was well within the scope of their authorization.

Dates and Duration

Apache will conduct offshore/transition zone seismic operations for approximately 8 to 9 months in offshore areas in open water periods from March 1 through December 31 annually over the course of 5 years. During each 24-hour period, seismic support activities may be conducted throughout the entire period; however, in-water airguns will only be active for approximately 2-3 hours during each of the slack tide periods. There are approximately four slack tide periods in a 24-hour period; therefore, airgun operations will be active during approximately 8-12 hours per day, if weather conditions allow. Two airgun source vessels will work concurrently on the spread, acquiring source lines approximately 12 km (7.5 mi) in length. Apache anticipates that a crew can acquire approximately eight of these 12km lines per day, assuming a crew can work 8-12 hours per day. Thus, the actual survey duration each year will take approximately 160 days over the course of 8 to 9 months. The vessels will be mobilized out of Homer or Anchorage with resupply runs occurring multiple times per week out of Homer, Anchorage, or Nikiski.

Specified Geographic Region

Each phase of the Apache program would cover land, intertidal transition zone, and marine environments in Cook Inlet, Alaska. However, only the portions occurring in the intertidal zone and marine environments have the potential to take marine mammals. The land-based portion of the program would not result in sound levels that would rise to the level of a marine mammal take.

The location of Apache's acquisition plan is depicted in Figure 1 in this document. The total seismic survey data acquisition locations encompass approximately 5,684 km

2

(2,195 mi

2

) of intertidal and offshore areas. This area is approximately 18% larger than the area contained in Apache's MMPA application. The additional area for seismic survey data acquisition considered in this rule is located in northern Cook Inlet near the Susitna Delta region and was considered in both the proposed and final rule. Apache will only operate in a portion of the entire survey area between March 1 and December 31 each year. There are numerous factors that influence the survey areas, including the geology of the Cook Inlet area, other permitting restrictions (

i.e.,

commercial fishing, Alaska Department of Fish and Game refuges), seismic imaging of leases held by other entities with whom Apache has agreements (

e.g.,

data sharing), overlap of sources and receivers to obtain the necessary seismic imaging data, and general operational restrictions (ice, weather, environmental conditions, marine life activity, etc.). Water depths for the program will range from 1-128m (0-420 ft).

ER20JY16.000

Detailed Description of Activities

The Notice of Proposed Rulemaking (80 FR 9510, February 23, 2015) contains a full detailed description of the 3D seismic survey, including the recording system, sensor positioning, and seismic source. That information has not changed and is therefore not repeated here.

Comments and Responses

A Notice of Proposed Rulemaking was published in the

Federal Register

on February 23, 2015 (80 FR 9510) for public comment. NMFS received a request for extension of the public comment period from the Natural Resource Defense Council on March 2, 2015. NMFS granted a 15-day extension to the public comment period, which ended on April 9, 2015. During the 45-day public comment period, NMFS received fourteen comment letters from the following: The State of Alaska Department of Natural Resources (AK DNR); the Alaska Chamber; the All American Oil Field; the Alaska Oil and Gas Association (AOGA); the Chugach Alaska Corporation; Cook Inlet Regional Inc. (CIRI); the International Fund for

Animal Welfare (IFAW); the Resource Development Council (RDC); Natural Resource Defense Council (NRDC); the Marine Mammal Commission (MMC); the public law class of the Vermont Law School (VLS); and three private citizens.

All of the public comment letters received on the Notice of Proposed Rulemaking (80 FR 9510, February 23, 2015) are available on our Web site at:

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

Following is a summary of the public comments and NMFS' responses.

Comment 1:

One private citizen requested that we deny issuance of the IHA because marine mammals would be killed as a result of the survey.

Response:

This activity is not expected to result in the death of any marine mammal species, and no such take is authorized. Extensive analysis of the proposed 3D seismic survey was conducted in accordance with the MMPA, Endangered Species Act (ESA), and National Environmental Policy Act (NEPA). We analyzed the impacts to marine mammals (including those listed as threatened or endangered under the ESA), to their habitat (including critical habitat designated under the ESA), and to the availability of marine mammals for taking for subsistence uses. The MMPA analyses revealed that the activities would have a negligible impact on affected marine mammal species or stocks and would not have an unmitigable adverse impact on the availability of marine mammals for taking for subsistence uses. The ESA analysis concluded that the activities likely would not jeopardize the continued existence of ESA-listed species or destroy or adversely modify designated critical habitat. The NEPA analysis concluded that there would not be a significant impact on the human environment.

Comment 2:

One private citizen requests that NMFS conduct research before and after the Apache survey activity to determine effects on wildlife.

Response:

NMFS agrees that pre- and post-activity monitoring is essential to analyze effects of the activity and gather crucial information. Therefore, NMFS is requiring Apache to conduct a pre and post-activity monitoring period of 30 minutes to assess movement of marine mammals into and out of the ensonified area. Apache also conducts monitoring efforts when sound sources are not in use which can provide additional context to the observations made during periods when the active sound sources are in use.

Comment 3:

The Resource Development Council, AK DNR, Alaska Chamber, All American Oilfield, AOGA, Chugach Alaska Corporation, and CIRI wrote letters in support of NMFS' issuance of 5-year regulations to Apache.

Response:

After careful evaluation of all comments and the data and information available regarding potential impacts to marine mammals and their habitat and to the availability of marine mammals for subsistence uses, NMFS has issued the final regulations to Apache to take marine mammals incidental to conducting a 3D seismic survey program in Cook Inlet for the period August 2016 to July 2021.

Comment 4:

The MMC and NRDC recommend that NMFS defer issuance of the regulations until such time as NMFS can, with reasonable confidence, support a conclusion that the activities would affect no more than a small number of Cook Inlet beluga whales and have no more than a negligible impact on the population. The MMC recommends that NMFS defer issuance until we have better information on the cause or causes of ongoing decline of the population and a reasonable basis for determining that authorizing additional takes would not contribute to or exacerbate that decline. The MMC continues to believe that any activity that may contribute to or that may worsen the observed decline should not be viewed as having a negligible impact on the population. NRDC urges NMFS to defer issuance of the rule, citing a letter dated Jan 13, 2014, from the MMC stating that NMFS has been unable to rule out cumulative disturbance associated with a broad suite of activities occurring in the Inlet, including oil and gas development, as a contributor to the decline of Cook Inlet beluga whales. Instead of issuing five-year regulations NRDC suggests that NMFS issue a one-year IHA.

Response:

In accordance with our implementing regulations at 50 CFR 216.104(c), we use the best available scientific evidence to determine whether the taking by the specified activity within the specified geographic region will have a negligible impact on the species or stock and will not have an unmitigable adverse impact on the availability of such species or stock for subsistence uses.

Based on the scientific evidence available, NMFS determined that the impacts of the 3D seismic survey program, which are primarily from acoustic exposure, would meet these standards. Moreover, Apache proposed and NMFS has required in the regulations a rigorous mitigation plan to reduce impacts to Cook Inlet beluga whales and other marine mammals to the lowest level practicable, including measures to power down or shutdown airguns if any beluga whale is observed approaching or within the Level B harassment zone and restricting activities within a 10 mi (16 km) radius of the Susitna Delta from April 15 through October 15, which is an important area for beluga feeding and calving in the spring and summer months. This shutdown measure is more restrictive than the standard shutdown measures typically applied, and combined with the Susitna Delta exclusion (minimizing adverse effects to foraging), is expected to reduce both the scope and severity of potential harassment takes, ensuring that there are no energetic impacts from the harassment that would adversely affect reproductive rates or survivorship.

Our analysis indicates that issuance of these regulations will not contribute to or worsen the observed decline of the Cook Inlet beluga whale population. Additionally, the ESA Biological Opinion determined that the issuance of an IHA is not likely to jeopardize the continued existence of the Cook Inlet beluga whales (or the western distinct population segment of Steller sea lions) or destroy or adversely modify Cook Inlet beluga whale critical habitat. The Biological Opinion also outlined Reasonable and Prudent Measures and Terms and Conditions to reduce impacts, which have been incorporated into the IHA. Therefore, based on the analysis of potential effects, the parameters of the seismic survey, and the rigorous mitigation and monitoring program, NMFS determined that the activity would have a negligible impact on the population. 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). Cumulative effects were also addressed in the EA and related Finding of No Significant Impact and Biological Opinion prepared for this action. Those documents, as well as the Alaska Marine Stock Assessments and the most recent abundance estimate for Cook Inlet beluga whales (Shelden

et al.,

2015), are part of NMFS' Administrative Record for this action, and provided the decision maker with information regarding other activities in the action area that affect marine mammals, an analysis of cumulative impacts, and other information relevant to the determination made under the MMPA.

Moreover, the seismic survey would take only small numbers of marine

mammals relative to their population sizes. The number of belugas likely and authorized to be taken represents less than 9.6% of the population. NMFS used a method that incorporates density of marine mammals overlaid with the anticipated ensonified area to calculate an estimated number of takes for belugas, which was estimated to be less than 10% of the stock abundance, which NMFS considers small. In addition to this quantitative evaluation, NMFS has also considered qualitative factors that further support the “small numbers” determination, including: (1) The seasonal distribution and habitat use patterns of Cook Inlet beluga whales, which suggest that for much of the time, only a small portion of the population would be potentially subjected to impacts from Apache's activity, as most animals are concentrated in upper Cook Inlet; and (2) the mitigation requirements, which provide spatio-temporal limitations that avoid impacts to large numbers of animals feeding and calving in the Susitna Delta and limit exposures to sound levels associated with Level B harassment. Based on all of this information, NMFS determined that the number of beluga whales likely to be taken is small. See response to Comment 4 and our small numbers analysis later in this document for more information about the small numbers determination for beluga whales and the other marine mammal species.

NMFS has made the necessary findings to issue the 5-yr regulations for Apache's activities. Nonetheless, NMFS agrees that caution is appropriate in the management of impacts on this small resident beluga population with declining abundance and constricted range. Accordingly, NMFS will issue annual LOAs, as appropriate, instead of a single 5-year LOA option. This will allow the agency to determine annually, in consideration of Apache monitoring reports and any other new information on impacts or Cook Inlet belugas (or other affected species), whether the level of taking will be consistent with the findings made for the total taking allowable under these 5-year regulations before issuing an LOA. Annual LOAs will also allow for, if necessary and appropriate, a public comment period. Additionally, this rule contains an adaptive management provision that allows for the modification of mitigation or monitoring requirements at any time (in response to new information) to ensure the least practicable adverse impact on the affected species and maximize the effectiveness of the monitoring program. We also note the MMPA and NMFS' implementing regulations allow for an LOA to be withdrawn or suspended, as appropriate, if, after notice and opportunity for public comment, we determine that the taking allowed is having, or may have, more than a negligible impact on the species or stock (among other circumstances). 16 U.S.C. 1371(a)(5)(B); 50 CFR 216.106(e).

Comment 5:

The MMC recommends that NMFS develop a policy that sets forth clear criteria and/or thresholds for determining what constitutes “small numbers” and “negligible impact” for the purpose of authorizing incidental takes of marine mammals. The MMC understands that NMFS has been working on developing a policy and would welcome an opportunity to discuss this policy further before it is finalized.

Response:

NMFS is in the process of developing both a clearer policy to outline the criteria for determining what constitutes “small numbers” and an improved analytical framework for determining whether an activity will have a “negligible impact” for the purpose of authorizing takes of marine mammals. We fully intend to engage the MMC in these processes at the appropriate time.

Comment 6:

The NRDC pointed by reference to the other proposed activities in Cook Inlet during the 2015 open water season. The NRDC, the MMC, and one private citizen note that NMFS must address the cumulative effects of activities in Cook Inlet on Cook Inlet beluga whales and whether the cumulative impacts of all the activities are having “either individually or in combination” a greater than negligible impact on marine mammals.

Response:

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). In addition, cumulative effects were addressed in the EA and Biological Opinion prepared for this action. The cumulative effects section of the EA has been expanded from the draft EA to discuss potential effects in greater detail. These documents, as well as the Alaska Marine Stock Assessments and the most recent abundance estimate for Cook Inlet beluga whales (Shelden

et al.,

2015) are part of NMFS' Administrative Record for this action, and provided the decision maker with information regarding other activities in the action area that affect marine mammals, an analysis of cumulative impacts, and other information relevant to the determination made under the MMPA.

Comment 7:

The NRDC states that NMFS failed to account for survey duration in the estimation of beluga whale takes and that NMFS based beluga takes using a predictive habitat density model (Goetz

et al.,

2012) that is based on data from summer months and confined to summer distribution when belugas are generally concentrated in the Upper Inlet, even though activity could occur year round. One private citizen also suggests that NMFS did not improve upon take estimation used in a previous IHA for Apache, which was found arbitrary and capricious.

Response:

The numerical estimation of take for beluga whales does consider survey duration in the calculation. The Goetz

et al.

(2012) model is the best available data for beluga density in Cook Inlet. The method used by NMFS to estimate take uses that data to estimate the number of belugas taken. This is done by multiplying the density of the area surveyed on a given day by the area ensonified on that day of surveying to yield the number of belugas that were likely exposed during that day of surveying. This is then added to the next day of surveying and so forth in an additive model until the number of 30 belugas is reached. If the number of 30 belugas is reached using this calculation before Apache has completed their 160 days of proposed surveying, survey activity must cease. Additionally, if they finish their 160 days without reaching the limit of 30 belugas their activity must still cease. The model, by being additive in nature for each day of surveying, accounts for the duration of the survey, as well as capturing a more specific density value than using an Inlet-wide density estimate.

Moreover, the model (or other numerical methods for estimating take) does not take into consideration the rigorous mitigation protocols that will be implemented by Apache, which will likely reduce the number of actual Level B harassment takes of Cook Inlet beluga whales. As mentioned previously, the rule contains a condition restricting Apache's airgun operations within 10 mi (16 km) of the mean higher high water line of the Susitna Delta from

April 15 through October 15. During this time, a significant portion of the Cook Inlet beluga whale population occurs in this area for feeding and calving. This setback distance includes the entire 160 dB radius of 5.9 mi (9.5 km) predicted for the full airgun array plus an additional 4.1 mi (6.5 km) of buffer, thus reducing the number of animals that may be exposed to Level B harassment thresholds during this important time. Apache is also required to shut down the airguns if any beluga whale is sighted approaching or entering the Level B harassment zone to avoid take. NMFS used the Goetz

et al.

(2012) model, which incorporates many years of NMML data collection and is considered the best available source of density estimation, with consideration of all of the mitigation measures required to be implemented, to authorize 30 beluga whale takes. This approach is reasonable and does not contradict available science and data of beluga whale distribution and local abundance during the period of operations. While the data used to create the model is from beluga surveys conducted in summer months, the majority of Apache's operations occur in summer months. Finally, unlike the take estimates for NMFS' 2012 IHA, which were found to be erroneous because they did not include a correction factor for the raw beluga survey data, the beluga take estimates in this rule making use the most current information in a predictive beluga habitat model to estimate how many belugas are likely to occur in the area that Apache plans to survey.

Comment 8:

The NRDC states that in the case of marine mammals other than beluga whales, NMFS repeated past errors associated with its use of raw NMML survey data. Cited errors in the density calculations include the failure to incorporate correction factors for missed marine mammals in the analysis and the failure to fully account for survey duration by multiplying densities (which are calculated on an hourly basis) by the number of survey days but not the number of hours in a day.

Response:

Correction factors for marine mammal surveys, with the exception of beluga whales, are not available for Cook Inlet. The primary purpose and focus of the NMFS aerial surveys in Cook Inlet for the past decade has been to monitor the beluga whale population. Although incidental observations of other marine mammals are noted during these surveys, they are focused on beluga whales. With the exception of the beluga whale, no detailed statistical analysis of Cook Inlet marine mammal survey results has been conducted, and no correction factors have been developed for Cook Inlet marine mammals. The only published Cook Inlet correction factor is for beluga whales. Developing correction factors for other marine mammals would have required different survey protocols and consideration of unavailable data such as Cook Inlet marine mammal detection rates, tidally-influenced, daily and seasonal movement patterns, with subsequent detailed statistical analyses of these data. For example, other marine mammal numbers are often rounded to the nearest 10 or 100 during the NMFS aerial survey; resulting in unknown observation bias. Therefore, the data from the NMFS surveys are the best available, and number of animals taken are still likely overestimated because of the assumption that there is a 100% turnover rate of marine mammals each day.

Survey duration was appropriately considered in the estimations by multiplying density by area of ensonification by number of survey days. NMFS does not calculate takes on an hourly basis, and, additionally, the multiple hours surveyed within a day are reflected in the area of ensonification, which considers the distance Apache can move within a day and is therefore larger than what would be covered in one hour. Additionally, as NMFS has used the density estimate from NMFS aerial surveys, multiplied by the area ensonified per day, multiplied by the number of days, this calculation produces the number of instances of exposure during the seismic survey. This is likely an overestimate of individuals taken by Level B harassment, as a single individual can be exposed on multiple days over the course of the survey, especially when a small seismic patch is shot over a period of multiple days. While protected species observers (PSOs) cannot detect every single animal within the Level B harassment zone, monitoring reports from similar past activities indicate that sightings did not exceed calculated projected take.

Comment 9:

The NRDC commented that NMFS underestimated the size of Apache's impact area by: (1) Using an outdated and incorrect threshold for behavioral take; and (2) disregarding the best available evidence on the potential for temporary and permanent threshold shift on mid- and high-frequency cetaceans and on pinnipeds. The NRDC also commented that it is irrational for NMFS to proceed with outdated acoustic thresholds when NMFS has developed a more appropriate method, stressing that take should not be authorized until the revision of acoustic thresholds for Level B take is complete.

Response:

The comment that NMFS uses an outdated and incorrect threshold for behavioral takes does not include any specific recommendations. NMFS uses 160 dB (rms) as the exposure level for estimating Level B harassment takes by non-continuous sound for most species in most cases. This threshold was established for underwater impulse sound sources 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). 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, in some cases suggesting that animals have been disturbed at lower levels and in others showing a lack of response when exposed to levels above 160dB. See 75 FR 49710, 49716 (August 13, 2010) (IHA for Shell seismic survey in Alaska). Accordingly, it is not a matter of merely replacing the existing threshold with a new one. NOAA is working to develop more sophisticated guidance for determining impacts from acoustic sources, including information for determining Level B harassment thresholds. Due to the complexity of the task, any guidance will require a rigorous review that includes internal agency review, public notice and comment, and additional 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 threshold for estimating takes of marine mammals in Cook Inlet by Level B harassment. However, we discuss the science on this issue qualitatively in our analysis of potential effects to marine mammals.

The comment that NMFS disregarded the best available evidence on the potential for temporary and permanent threshold shift on mid- and high-frequency cetaceans and on pinnipeds does not contain any specific recommendations. We acknowledge there is more recent information available bearing on the relevant exposure levels for assessing temporary and permanent hearing impacts. (See,

e.g.,

NMFS'

Federal Register

notice (78 FR 78822, December 27, 2013) for

NMFS' draft guidance for assessing the onset of permanent and temporary threshold shift.) Again, NMFS will be issuing guidance, but that process is not complete, so we did not use it to assign new thresholds for calculating take estimates for hearing impacts. However, we did consider the information, and it suggests the current 180 dB (for cetaceans) and 190 dB (for pinnipeds) thresholds are appropriate. See 75 FR 49710, 49715, 49724 (August 13, 2010) (IHA for Shell seismic survey in Alaska; responses to comment 8 and comment 27). Moreover, the required mitigation is designed to ensure there are no exposures at levels thought to cause hearing impairment, and further, for belugas, and groups of killer whales and harbor porpoises in the project area, mitigation measures are designed to reduce or eliminate exposures to Level B harassment thresholds as well.

Comment 10:

The NRDC comments that the proposed mitigation measures fail to meet the MMPA's “least practicable adverse impact” standard. The NRDC provides a list of approximately eight measures that NMFS “failed to consider or adequately consider.”

Response:

NMFS provided a detailed discussion of proposed mitigation measures and the MMPA's “least practicable impact” standard in the notice of the proposed IHA (80 FR 9510, February 23, 2015), which are repeated in the “Mitigation” section of this notice. The measures that NMFS allegedly failed to consider or adequately consider are identified and discussed below:

1. Use of quieting technologies, such as vibroseis and gravity gradiometry, to reduce or eliminate the need for airguns, and delaying seismic acquisition in higher density areas until the alternative technology of marine vibroseis becomes available: Apache requested takes of marine mammals incidental to the seismic survey operations described in the rulemaking application, which identified airgun arrays as the technique Apache would employ to acquire seismic data. It would be inappropriate for NMFS to change the specified activity and it is beyond the scope of the request for takes incidental to Apache's operation of airguns and other active acoustic sources.

Apache knows of no alternative available technology scaled for industrial use that is reliable enough to meet the environmental challenges of operating in Cook Inlet. Apache is aware that many prototypes are currently in development, and may ultimately incorporate these new technologies into their evaluation process as the technologies become commercially viable. However, none of these technologies are currently ready for use on a large scale in Cook Inlet. As this technology is developed, Apache will evaluate its utility for operations in the Cook Inlet environment.

2. Required use of the lowest practicable source level in conducting airgun activity: Apache determined that the 2400 in

3

array is the minimum source level needed to provide the data required for Apache's operations.

3. Seasonal exclusions around river mouths, including early spring (pre-April 14) exclusions around the Beluga River and Susitna Delta, and avoidance of other areas that have a higher probability of beluga occurrence: NMFS has required a 10-mile (16 km) exclusion zone around the Susitna Delta (which includes the Beluga River) in this regulation. This mitigation mirrors a measure in the Incidental Take Statement for the 2012 and 2013 Biological Opinions. Seismic survey operations involving the use of airguns will be prohibited in this area between April 15 and October 15. In both the MMPA and ESA analysis, NMFS determined that this date range is sufficient to protect Cook Inlet beluga whales and the critical habitat in the Susitna Delta. While data indicate that belugas may use this part of the inlet year round, peak use occurs from early May to late September. NMFS added a 2-week buffer on both ends of this peak usage period to add extra protection to feeding and calving belugas. NMFS also expanded the exclusion zone to start from the mean higher high water line to the mean lower low water line. (In addition, the Alaska Department of Fish and Game (ADF&G) prohibits the use of airguns within 1 mi (1.6 km) of the mouth of any stream listed by the ADF&G on the Catalogue of Waters Important for the Spawning, Rearing, or Migration of Anadromous Fishes. See additional explanation in “Mitigation Measures Considered but not Required” section, later in this document.)

4. Limitation of the mitigation airgun to the longest shot interval necessary to carry out its intended purpose: This general comment contained no specific recommendations. Apache requires shot intervals of 50m at a speed of 2-4 knots to obtain the information from their survey. However NMFS has added a mitigation measure that Apache reduce the shot interval for the mitigation gun to one shot per minute.

5. Immediate suspension of airgun activity, pending investigation, if any beluga strandings occur within a distance of 19km (two times the 160dB isopleth) the survey area: If NMFS becomes aware of any live beluga strandings, Apache will be notified and required to shutdown if the stranding event is within 19km (two times the 160 dB isopleth) of Apache's operations until the circumstances of the stranding are reviewed. The regulation also requires Apache to immediately cease activities and report unauthorized takes of marine mammals, such as live stranding, injury, serious injury, or mortality. NMFS will review the circumstances of Apache's unauthorized take and determine if additional mitigation measures are needed before activities can resume to minimize the likelihood of further unauthorized take and to ensure MMPA compliance. Apache may not resume activities until notified by NMFS. Separately, the regulation includes measures to be implemented if injured or dead marine mammals are sighted and the cause cannot be easily determined. In those cases, NMFS will review the circumstances of the stranding event while Apache continues with operations.

6. Establishment of a larger exclusion zone for beluga whales that is not predicated on the detection of whale aggregations or cow-calf pairs: Both the proposed rule notice and the issued regulations contain a requirement for Apache to delay the start of airgun use or shutdown the airguns if a beluga whale is visually sighted or detected by passive acoustic monitoring approaching or within the 160-dB disturbance zone until the animal(s) are no longer present within the 160-dB zone. The measure applies to the sighting of any single beluga whale, not just sightings of groups or cow-calf pairs.

7. Identifying compensatory mitigation such as habitat restoration to be undertaken by industry within the Inlet: NMFS is issuing an Authorization for incidental take of marine mammals for Apache's seismic survey program. NMFS is required to consider the practicability of implementation of the measure as well as proven or likely effectiveness of the measure. NMFS is not currently aware of literature demonstrating the effectiveness of habitat restoration on mitigating the effects of airgun noise. Additionally, NMFS considers effects to beluga habitat to be primarily acoustic and temporary in nature, which is difficult to mitigate.

8. Creating quiet zones in highly important habitat: NMFS agrees that reduction of noise in habitat known to be essential for marine mammals is also area that should be targeted for measures to reduce noise. This principle

is incorporated through the exclusion zone of the Susitna Delta, ensuring that airgun noise is not prevalent within this section of Critical Habitat Area 1 for Cook Inlet belugas.

Comment 11:

The MMC suggests that NMFS work with Apache to explore the possibility of fixed passive acoustic monitoring. The NRDC echoed support for the use of passive acoustic monitoring techniques, moorings, and unmanned aerial systems.

Response:

The passive acoustic monitoring plan for Apache Alaska Corporation's 2012 survey anticipated the use of a bottom-mounted telemetry buoy to broadcast acoustic measurements using a radio-system link back to a monitoring vessel. Although a buoy was deployed during the first week of surveying under the 2012 IHA, it was not successful. Upon deployment, the buoy immediately turned upside down due to the strong current in Cook Inlet. After retrieval, the buoy was not redeployed and the survey used a single omni-directional hydrophone lowered from the side of the mitigation vessel. During the entire 2012 survey season, Apache's PAM equipment yielded only six confirmed marine mammal detections, one of which was a Cook Inlet beluga whale. The single Cook Inlet beluga whale detection did not, however, result in a shutdown procedure.

Additionally, Joint Base Elmendorf-Fort Richardson, the National Marine Mammal Laboratory, and Alaska Department of Fish &Game conducted a 2012 study (Gillespie

et al.,

2013) to determine if beluga whale observations at the mouth of Eagle River corresponded with acoustic detections received by a PAMBuoy data collection system. The PAMBuoy data collection system was deployed in the mouth of Eagle River from 12-31 August 2012. This study was a trial period conducted with one hydrophone at the mouth of the river. Overall, it was successful in detecting beluga whale echolocation clicks and whistles, but PAM systems in this location may be limited due to: interactions with ice and debris, transmission distance limitations, detection distance limitations, and masking due to non-target sound sources. In addition, acoustic detections may be largely duplicative of daylight visual observations, the system cost is not trivial, and mooring of buoys can be a challenge in this environment of extreme tides. However, despite these challenges with PAM in certain circumstances, there is still value in exploring its use and it is not logistically impractical for this project and, therefore, Apache will be deploying a passive acoustic monitoring system for use during nighttime operations.

Comment 12:

The MMC requested clarification regarding Authorizations sought by Apache and SAE and inquired if these Authorizations were for the same project. The MMC recommends that NMFS encourage SAE and other applicants proposing to conduct seismic surveys in Cook Inlet in 2015 to collaborate on those surveys and, to the extent possible, submit a single application seeking authorization for incidental harassment of marine mammals.

In a similar comment, the NRDC expressed concern over the number of activities proposed in the same area for the same season referencing applications for: Furie, Bluecrest, Buccaneer, and Apache.

Response:

We agree and have encouraged Apache to cooperate with other interested parties to minimize the impacts of new seismic surveys in the region. Apache has told NMFS that their proposed activities are a separate project from that of SAE. SAE has also withdrawn their request for an IHA in 2016. Apache will continue its discussions with other operators in Cook Inlet to find opportunities to joint venture in oil and gas operations, including seismic data acquisition. In addition, NMFS will do what it can to encourage such collaborations when they result in a reduction in disturbance to protected species or their habitats.

NMFS is currently aware of one additional proposal for seismic exploration in Cook Inlet for 2016. Additionally, there are applications submitted for one geophysical survey and one test well drilling operation, which is proposed for a site much farther south than any of the above mentioned operations.

Comment 13:

Both the NRDC and the MMC comment that authorization should not be issued until the Cook Inlet Beluga Whale Take Recovery Plan is finalized and published.

Response:

The Cook Inlet Beluga Whale Recovery Plan is still under development and currently available in published draft form. It is not necessary to have the Recovery Plan finalized to authorize Apache's activity, as NMFS is still able to make a negligible impact determination for beluga whales using the best available information. NMFS will continue to work with Apache to focus mitigation and monitoring efforts to cover some of the focus points highlighted in the Draft Recovery Plan as appropriate.

Comment 14:

The MMC comments that various applicants in the Cook Inlet region have used differing density estimates for calculating take of marine mammal species in the Inlet and that all applicants should use the same densities.

Response:

The density estimates used for the 2015 SAE IHA and in the Final Rule for Apache, specifically for harbor porpoises and killer whales, are the best available science at this time. The data are from NMFS aerial surveys over a ten year period (2000-2012). NMFS is working with applicants to incorporate these density estimates into future applications and take authorizations. However, for harbor seals, which are known to have clustered distributions, density estimates and derived take estimation may vary based on action area boundaries, site-specific knowledge of abundance, density, seasonality, or other qualities that could allow for a more nuanced assessment of the density in a given location.

Comment 15:

The MMC comments that Apache should be required to investigate and report on detection probabilities from various observation platforms for differing sea states and light conditions.

Response:

NMFS acknowledges that collecting detection probabilities from various platforms under different conditions would be very useful information and could better inform monitoring reports by discerning how many animals were likely taken. However, constructing a study to investigate detection probabilities requires a great deal of planning and many more observers than are involved in this survey. NMFS would like to work with the MMC to discuss how best to conduct this work and refine detection probabilities for seismic surveys.

Comment 16:

The NRDC comments that the effective dates in the proposed rule suggest a curtailing of public review in violation of the Administrative Procedure Act in that they do not allow for NMFS to sufficiently review and address public comments before the rule's proposed date of effectiveness.

Response:

The date provided in the proposed rule was the date proposed by the applicant originally for this work. NMFS has had ample time to review and address public comments prior to making its determinations for this rule and the effective dates have been adjusted accordingly. The dates of effectiveness for the rule have shifted since the proposed rule publication, giving NMFS adequate time to review and respond to public comment submitted by the close of public comment on April 9, 2015.

Comment 17:

The MMC comments that the use of turnover factors for take estimation in the proposed rule is inappropriate. The MMC requests that NMFS use the same density × daily ensonified area × number of days formula used for previous authorizations. The MMC also notes that if NMFS uses a turnover factor that it should consult the literature to create a more biologically relevant turnover factor than that derived from Wood

et al.

(2012). The MMC also recommends that NMFS re-evaluate the necessary determinations with the new take estimates.

Response:

After reviewing public comment submissions, NMFS decided to adjust the method used to estimate take in Cook Inlet. NMFS removed the use of turnover factors from Wood

et al.

(2012) completely from take estimation. The daily ensonified area × number of survey days × density method was used for all species to calculate the number of instances of exposure except for belugas, harbor seals, humpback whales, and Steller sea lions. Using sighting reports collected by the Alaska region, NMFS has determined that given the distribution of Steller sea lions in Cook Inlet, it is unlikely that more than 20 individuals will be taken during the course of one year. Similarly, while several humpbacks are reported in Cook Inlet each year, it is unlikely that Apache will expose more than two humpbacks during their surveying each year.

For Cook Inlet belugas, NMFS derived a method to ensure that Apache take no more than 30 belugas annually, which is approximately 10 percent of the population. Using the Goetz

et al.

(2012) habitat model, Apache will calculate the possible take (density from the model × the area surveyed that day) for each day and sum the possible take across days until 30 is reached. When the take per day summed amounts to 30, Apache must cease surveying for the season. As an additional measure, and to account for a sudden sighting of a large group of belugas, Apache will also cease surveying if 30 belugas are visually observed to enter the 160dB harassment zone.

For harbor seals, it is likely the daily ensonified area produces an overestimate of individuals taken, as described in more details in the Estimated Take section. NMFS applied the survey method used by Apache, patch shooting, and applied the number of days required to shoot a patch to estimate the number of days an animal at a given haulout could be exposed. This is an average of 3 days, but no more than 5. When this factor is applied to the estimate of instances of exposures by using the ensonified daily area method, the number of exposed individual seals can be more reasonably estimated and is much lower than the number of instances of exposure, at 6,438. This number is appropriately reduced even further as individuals could be exposed at multiple patches. Separately, NMFS then considered the harbor seal densities alongside monitoring reports from Apache's work in 2012. NMFS looked at the monitoring reports from Apache's aerial surveys in June and used correction factors from the literature to determine the number of seals in the water. This number was also multiplied to match the number of Apache's proposed survey days (160) to yield a number of 8,250 instances of take, notably lower than 24,279. Additionally, in their 147 days of surveying, Apache reported sightings of 285 seals. While it is understood that visual observations likely underestimate the actual number of exposures, as all seals in the 160dB range are not visible, it is worth noting that the number of visual estimates is 131 times smaller than the calculated number of exposures using the daily ensonified area method. These methods are discussed in greater detail in the Takes Estimation section of this document, but in summary we concluded that not more than 25% of the population of harbor seals would be taken. The daily ensonified method results in an estimate of 24,279 instances of exposure, but this is likely an over-estimation of the number of instances of exposure and also does not represent the number of unique individuals in the population taken during the course of the survey. As explained in the Negligible Impact Determination and Small Numbers sections below, NMFS is able to make the necessary determinations for all species using the new take estimation methodology.

Comment 18:

Both the NRDC and MMC commented that the use of figures for the survey area was unclear and it was difficult to determine if the project area was expanded after the

Federal Register

Notice of Receipt of Apache's Application (79 FR 45428).

Response:

NMFS acknowledges that the figure used was unclear. The analysis in the proposed rule, however, was for the action area being considered, which did not change between the proposed and final rule.

Comment 19:

NRDC commented that NMFS did not take higher densities of beluga whales in the Upper Inlet into account when making a negligible impact determination, analyzing mitigation requirements, or adopting a cap to allow Apache geographic flexibility during the survey. The MMC also commented that the analysis did not take into account the expanded survey area in the Upper Inlet.

Response:

NMFS believes that increased density of beluga whales in the Upper Inlet is taken into account, despite the geographic flexibility allowed by Apache. The area ensonified each day will be multiplied by the applicable 1 km

2

grid cell densities taken from the Goetz

et al.

(2012) paper. The modeling in this paper clearly demonstrates a higher density of belugas in the Upper Inlet. Therefore, using these densities accounts for area of high beluga density in the Upper Inlet. Additionally, NMFS has created an exclusion zone within 10 miles of the Susitna River Delta, an area of known importance for belugas in the summer, to ensure that Apache's activity does not interfere with such an important area. When considering these things in combination, NMFS was able to make a negligible impact determination. NMFS also clarifies that while an ambiguous figure was used, Apache is not proposing to expand the survey beyond what was analyzed in the proposed rule.

Comment 20:

The NRDC commented that the number of takes in the regulatory text and Table 5 of the preamble were different.

Response:

NMFS acknowledges the discrepancy and points to Table 5 of the preamble for the correct take estimates. However, because methodology has been altered between the issuance of the proposed rule and the final rule due to public comment and analysis of monitoring reports and sightings information, these take tables have changed.

Comment 21:

The MMC comments that NMFS should clarify if Apache should be requesting take of humpback whales, minke whales, and Dall's porpoises. Furthermore, NMFS should work with applicants to determine which species should be included in authorizations.

Response:

Apache did not request take of humpback whales, minke whales, and Dall's porpoises. However, because they have been sighted during Apache's previous surveying, NMFS has decided to authorize Level B harassment for small numbers of minke whales and Dall's porpoise. Additionally, take of humpback whales was analyzed in the Biological Opinion, due to the number of reported sightings of humpback whales in Cook Inlet in summer 2015.

Comment 22:

The MMC requests that NMFS periodically reconvene the Cook Inlet Beluga Whale Recovery Team (CIBWRT) and related working groups

to prioritize research and monitoring recommendations as well as other recovery plan items.

Response:

The determination of whether and when to reconvene the COBWRT is outside of the scope of this authorization. However, NMFS plans to incorporate recommendations from the Cook Inlet Beluga Whale Recovery Plan as appropriate into monitoring and mitigation requirements after the recovery plan is finalized through the adaptive management provisions of the rule.

Comment 23:

The MMC recommends that NMFS restrict all seismic activity occurring in Critical Habitat Area 1 to the time between October 15th and April 15th to minimize impacts to belugas using this seasonally vital habitat.

Response: Given the seasonal nature of beluga concentrations, and their tendency to congregate in areas near Knik Arm and Turnagain Arm in the summer months, NMFS believes that the Susitna River Delta exclusion zone of 10 nmi from the MLLW line between the Susitna and Beluga Rivers is sufficient closure to protect beluga use of that portion of their critical habitat during times of high use.

Comment 24:

The NRDC recommends that NMFS require seismic operators to contribute to a comprehensive monitoring plan to better understand beluga distribution, individual effects, and cumulative effects of human activities on beluga whales.

Response:

NMFS believes that seismic operators have a substantial amount of information to contribute to our understanding of Cook Inlet beluga distribution, particularly through monitoring reports. It is also crucial to better understand individual and cumulative effects of human activities on belugas. NMFS is working to compile and analyze monitoring reports across all authorized activities to analyze effectiveness of mitigation and inform further monitoring plans for future Authorizations. We plan to develop a comprehensive monitoring plan for Cook Inlet concurrently with the development of the Environmental Impact Statement on the Issuance of Take Authorizations in Cook Inlet, Alaska (79 FR 61616).

Comment 25:

One private citizen commented that Apache should pay a large sum of money to a superfund to mitigate damage from the project by buying land for conservation easements or funding alternative energy research. This commenter also states that the only effective way to mitigate serious impacts is to remove airguns from sensitive environmental areas, cap activities by region and year, and promote alternative energies.

Response:

Where applicable, Apache has already proposed to implement certain measures mentioned above. The mandatory seasonal closure of the Susitna Delta from April 15-October 15 annually removes airguns from a portion of essential habitat at time of high use for belugas. The mitigation and monitoring in this rule represent the most effective and practicable means of reducing the impacts of Apache's activities on the affected marine mammal populations and their habitat. The purchase of land is not applicable to ensuring the least practicable adverse impact for this activity under the MMPA.

Comment 26:

One private citizen commented that the extended timeline of the project did not receive feedback from the community. There were also several comments included that referenced environmental impacts of drilling by Apache.

Response:

The public comment period, which was extended from 30 to 45 days, provided reasonable time for interested parties to submit public comment regarding the proposed regulations and many such comments were received by NMFS. NMFS would like to reiterate that the petition for regulations relates to seismic surveying by Apache in Cook Inlet and that no portion of these regulations pertains to drilling activities.

Comment 27:

IFAW comments that the effects of noise from seismic activity contribute to problems between vessels and whales, including ship strike and entanglement.

Response:

NMFS is aware that ship strikes and entanglements can occur in locations where whales and certain human activities co-exist. However, NMFS is not aware of any studies that demonstrate seismic noise increases the likelihood of these occurrences. NMFS is unaware of any entanglements or ship strikes that have occurred from seismic operations in Cook Inlet. IFAW did not provide citations for NMFS to delve further into these claims.

Comment 28:

The public law class of VLS comments that a mass stranding event, similar to the 2008 stranding in Madagascar, could reduce beluga numbers by one third.

Response:

NMFS does not believe that a mass stranding similar to that off Madagascar in 2008 could occur from the proposed seismic survey considered in the rulemaking for Apache. There are several distinctions between the survey in Madagascar and Apache's survey: equipment type, type of environment, and species of cetacean considered. The Madagascar stranding was secondarily associated with multibeam echosounder use, not a seismic survey, operating at a different frequency than that of airguns and conducting operations in a different manner that was specifically problematic for the species and environment present. Additionally, the mammals that stranded were melon headed whales, which have a large average group size and are deep divers, and those particular animals incurred secondary health problems from their extended time spent stranded following their initial behavioral response to the sound exposure. Lastly, the type of surveying proposed by Apache has been conducted fairly consistently in Cook Inlet under IHAs, and has not caused mass strandings of Cook Inlet belugas or other Cook Inlet marine mammal species.

Comment 29:

The public law class of VLS comments that allowing take for the proposed activity is a mismanagement of ESA protections for endangered belugas.

Response:

NMFS disagrees. This rulemaking is undertaken pursuant to the MMPA, not the ESA. However, because we proposed to authorize take of ESA-listed species, including Cook Inlet belugas, consultation under section 7 of the ESA is required. The Biological Opinion for this activity concluded jeopardy was not likely, and therefore the take associated with this rule is considered allowable under the MMPA and ESA.

Description of Marine Mammals in the Area of the Specified Activity

The marine mammal species under NMFS's jurisdiction that could occur near operations in Cook Inlet include four cetacean species: Beluga whale (

Delphinapterus leucas

), humpback whale (

Megaptera noveangliae

), killer whale (

Orcinus orca

), harbor porpoise (

Phocoena phocoena

), Dall's porpoise (

Phocoenoides dalli),

minke whale (

Balaenoptera acutorostrata

), and gray whale (

Eschrichtius robustus

) and two pinniped species: Harbor seal (

Phoca vitulina richardsi

) and Steller sea lions (

Eumetopias jubatus

). The marine mammal species that is likely to be encountered most widely (in space and time) throughout the period of the planned surveys is the harbor seal. While killer whales, humpback whales, minke whales, Dall's porpoise, and gray whales as well as Steller sea lions have been sighted in upper Cook Inlet, their occurrence is considered rare in that portion of the Inlet.

Of the nine marine mammal species likely to occur in the marine survey area, Cook Inlet beluga whales, Central

North Pacific humpback whales, and Steller sea lions are listed as endangered under the ESA (Steller sea lions are divided into two distinct population segments (DPSs), an eastern and a western DPS; the relevant DPS in Cook Inlet is the western DPS). The eastern DPS was recently removed from the endangered species list (78 FR 66139, November 4, 2013).

Table 1—Table of Stocks Expected To Occur in the Project Area

Species

Stock

ESA/MMPA status;

1

strategic

(Y/N)

Stock abundance (CV, N

min

, year of most recent abundance survey)

2

Relative occurrence in Cook Inlet; season of occurrence

Humpback whale

Central North Pacific

E/D;Y

7,469 (0.095;5,833;2000)

Occasionally seen in Lower Inlet, summer, rare in upper inlet.

Gray whale

Eastern North Pacific

-; N

19,126 (0.071; 18,017; 2007)

Rare migratory visitor; late winter.

Killer whale

Alaska Resident

-;N

2,347 (N/A; 2,084; 2009)

Occasionally seen in Lower Cook Inlet.

Gulf of Alaska, Aleutian Island, Bering Sea Transient

-;N

345 (N/A; 303; 2003)

Beluga whale

Cook Inlet

E/D;Y

312 (0.10; 280; 2012)

Use upper Inlet in summer and winter and lower inlet primarily in winter: Annual.

Minke whale

Alaska

-;N

1,233 (0.034;N/A;2003)

Infrequently occur but reported year-round.

Dall's porpoise

Alaska

-:N

106,000

3

(0.20; N/A; 1991)

Infrequently found in Lower Inlet.

Harbor porpoise

Gulf of Alaska

-;Y

31,046 (0.214; 25,987; 1998)

Widespread in the Inlet: annual (less in winter).

Steller sea lion

Western DPS

E/D;Y

79,300 (N/A; 45,659; 2012)

Primarily found in lower Inlet, rare in upper inlet.

Harbor seal

Alaska—Cook Inlet

-;N

22,900 (0.053; 21,896; 2006)

Frequently found in upper and lower inlet ; annual (more in northern Inlet in summer).

1

Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.

2

CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks of pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction factor derived from knowledge of the specie's (or similar species') life history to arrive at a best abundance estimate; therefore, there is no associated CV. In these cases, the minimum abundance may represent actual counts of all animals ashore.

3

Because there is such little data regarding Dall's porpoises in Alaska, these population numbers refer to the Gulf of Alaska portion of the Alaska stock only.

Pursuant to the ESA, critical habitat has been designated for Cook Inlet beluga whales and Steller sea lions. The action falls within critical habitat designated in Cook Inlet for beluga whales but is not within critical habitat designated for Steller sea lions. On April 11, 2011, NMFS announced the two areas of beluga whale critical habitat (76 FR 20180) comprising 7,800 km

2

(3,013 mi

2

) of marine habitat. Designated beluga whale Critical Habitat Area 1 consists of 1,909 km

2

of Cook Inlet, north of Three Mile Creek and Point Possession. Critical Habitat Area 1 contains shallow tidal flats or mudflats and mouths of rivers that provide important areas for foraging, calving, molting, and escape from predators. High concentrations of beluga whales are often observed in these areas from spring through fall. Critical Habitat Area 2 consists of 5,891 km

2

located south of Critical Habitat Area 1 and includes waters between Critical Habitat area 1 and 60°15′ North Latitude as well as nearshore areas along western Cook Inlet and Kachemak Bay. Critical Habitat Area 2 consists of known fall and winter foraging and transit habitat for beluga whales, as well as spring and summer habitat for smaller concentrations of beluga whales. Approximately 711 km

2

of Apache's 5684 km

2

seismic survey area is in the designated beluga whale Critical Habitat Area 1 and approximately 4,200 km

2

is in the designated beluga whale Critical Habitat Area 2.

There are several species of mysticetes that have been observed infrequently in lower Cook Inlet, including minke whale (

Balaenoptera acutorostrata)

and fin whale (

Balaenoptera physalus

). Because of their infrequent occurrence in the location of seismic acquisition, they are not included in this rule. Sea otters also occur in Cook Inlet. However, sea otters are managed by the U.S. Fish and Wildlife Service and are therefore not considered further in this rule.

Beluga Whale (Delphinapterus leucas)

Cook Inlet beluga whales have not made significant progress towards recovery since they were listed as endangered in 2008. Data indicate that the Cook Inlet population of beluga whales has been decreasing at a rate of 0.6 percent annually between 2002 and 2012 (Allen and Angliss, 2014). One review of the status of the population indicated that there is an 80% chance that the population will decline further (Hobbs and Shelden, 2008).

Cook Inlet beluga whales reside in Cook Inlet year-round, although their distribution and density changes seasonally. Factors that are likely to influence beluga whale distribution within the inlet include prey availability, predation pressure, sea-ice cover and other environmental factors, reproduction, sex and age class, and human activities (Rugh

et al.,

2000; NMFS 2008). Seasonal movement and density patterns as well as site fidelity appear to be closely linked to prey

availability, coinciding with seasonal salmon and eulachon concentrations (Moore

et al.,

2000). For example, during spring and summer, beluga whales are generally concentrated near the warmer waters of river mouths where prey availability is high and predator occurrence is low (Huntington 2000; Moore

et al.,

2000). During the winter (November to April), belugas disperse throughout the upper and mid-inlet areas, with animals found between Kalgin Island and Point Possession (Rugh

et al.,

2000). During these months, there are generally fewer observations of beluga whales in the Anchorage and Knik Arm area (NMML 2004; Rugh

et al.,

2004).

Beluga whales use several areas of the upper Cook Inlet for repeated summer and fall feeding. The primary hotspots for beluga feeding include the Big and Little Susitna rivers, Eagle Bay to Eklutna River, Ivan Slough, Theodore River, Lewis River, and Chickaloon River and Bay (NMFS, 2008). Availability of prey species appears to be the most influential environmental variable affecting Cook Inlet beluga whale distribution and relative abundance (Moore

et al.,

2000). The patterns and timing of eulachon and salmon runs have a strong influence on beluga whale feeding behavior and their seasonal movements (Nemeth

et al.,

2007; NMFS, 2008). The presence of prey species may account for the seasonal changes in beluga group size and composition (Moore

et al.,

2000). Aerial and vessel-based monitoring conducted by Apache during the March 2011 2D test program in Cook Inlet reported 33 beluga sightings. One of the sightings was of a large group (~25 individuals on March 27, 2011) of feeding/milling belugas near the mouth of the Drift River. If belugas are present during the late summer/early fall, they are more likely to occur in shallow areas near river mouths in upper Cook Inlet. For example, no beluga whales were observed in Trading Bay during Apache's 2D SSV conducted in September 2011, likely because during that time of year they were primarily located in the upper regions of Cook Inlet.

Humpback Whale (Megaptera novaeangliae)

Although there is considerable distributional overlap in the humpback whale stocks that use Alaska, the whales seasonally found in lower Cook Inlet are probably of the Central North Pacific stock. Listed as endangered under the ESA, this stock has recently been estimated at 7,469, with the portion of the stock that feeds in the Gulf of Alaska estimated at 2,845 animals (Allen and Angliss 2014). The Central North Pacific stock winters in Hawaii and summers from British Columbia to the Aleutian Islands (Calambokidis

et al.,

1997), including Cook Inlet.

Humpback use of Cook Inlet is largely confined to lower Cook Inlet. They have been regularly seen near Kachemak Bay during the summer months (Rugh

et al.,

2005a), and there is a whale-watching venture in Homer capitalizing on this seasonal event. There are anecdotal observations of humpback whales as far north as Anchor Point, with recent summer observations extending to Cape Starichkof (Owl Ridge 2014). Humpbacks might be encountered in the vicinity of Anchor Point if seismic operations were to occur off the point during the summer. In 2013, Apache encountered a humpback and calf in the ensonified area during seismic operations.

Killer Whales (Orcinus orca)

In general, killer whales are rare in upper Cook Inlet. Transient killer whales are known to feed on beluga whales, and resident killer whales are known to feed on anadromous fish (Shelden

et al.,

2003). The availability of these prey species largely determines the likeliest times for killer whales to be in the area. Between 1993 and 2004, 23 sightings of killer whales were reported in the lower Cook Inlet during aerial surveys by Rugh

et al.

(2005). Surveys conducted over a span of 20 years by Shelden

et al.

(2003) reported 11 sightings in upper Cook Inlet between Turnagain Arm, Susitna Flats, and Knik Arm. No killer whales were spotted during surveys by Funk

et al.

(2005), Ireland

et al.

(2005), Brueggeman

et al.

(2007a, 2007b, 2008), or Prevel Ramos

et al.

(2006, 2008). Eleven killer whale strandings have been reported in Turnagain Arm, six in May 1991 and five in August 1993. NMFS aerial survey data spanning 13 years conducted in June each year have reported sightings ranging from 0 to 33 whales in a single year, although these surveys extend beyond the action area of Apache's survey. Sightings data can be found in Table 5 of Apache's application. Therefore, very few killer whales, if any, are expected to approach or be in the vicinity of the action area.

Harbor Porpoise (Phocoena phocoena)

Previously estimated density for harbor porpoises in Cook Inlet is 7.2 per 1,000 km

2

(Dahlheim

et al.,

2000), suggesting that only a small number use Cook Inlet. Data from NMFS aerial surveys (Table 5 in Apache's application) flown annually in June from 2000-2012 sighted anywhere from 0 to 100 porpoises in a single season. The densities derived from this data range from 0 to 0.014 animals per km

2

. Harbor porpoise have been reported in lower Cook Inlet from Cape Douglas to the West Foreland, Kachemak Bay, and offshore (Rugh

et al.,

2005). Small numbers of harbor porpoises have been consistently reported in upper Cook Inlet between April and October, but more recent observations have recorded higher numbers (Prevel Ramos

et al.,

2008). Prevel Ramos

et al.

(2008) reported 17 harbor porpoises from spring to fall 2006, while other studies reported 14 in the spring of 2007 (Brueggeman

et al.,

2007) and 12 in the fall of 2007 (Brueggeman

et al.,

2008). During the spring and fall of 2007, 129 harbor porpoises were reported between Granite Point and the Susitna River; however, the reason for the increase in numbers of harbor porpoise in the upper Cook Inlet remains unclear and the disparity between this result and past sightings suggests that it may be an anomaly. The spike in reported sightings occurred in July, which was followed by sightings of 79 harbor porpoises in August, 78 in September, and 59 in October 2007. It is important to note that the number of porpoises counted more than once was unknown, which suggests that the actual numbers are likely smaller than those reported. In 2012, Apache marine mammal observers recorded 137 sightings of 190 estimated individuals; a similar count to the 2007 spike previously observed. In addition, recent passive acoustic research in Cook Inlet by the Alaska Department of Fish and Game and the National Marine Mammal Laboratory have indicated that harbor porpoises occur in the area more frequently than previously thought, particularly in the West Foreland area in the spring (NMFS 2011); however overall numbers are still unknown at this time.

Dall's Porpoise (Phocoenoides dalli)

Dall's porpoise are widely distributed throughout the North Pacific Ocean including Alaska, although they are not found in upper Cook Inlet and the shallower waters of the Bering, Chukchi, and Beaufort Seas (Allen and Angliss 2014). Compared to harbor porpoise, Dall's porpoise prefer the deep offshore and shelf slope waters. The Alaskan population has been estimated at 83,400 animals (Allen and Angliss 2014), making it one of the more common cetaceans in the state. Dall's porpoise have been observed in lower Cook Inlet, including Kachemak Bay and near Anchor Point (Owl Ridge 2014), but sightings there are rare. There is a

remote chance that Dall's porpoise might be encountered during seismic operations along the Kenai Peninsula.

Minke Whale (Balaenoptera acutorostra)

Minke whales are the smallest of the rorqual group of baleen whales reaching lengths of up to 35 feet. They are also the most common of the baleen whales, although there are no population estimates for the North Pacific, although estimates have been made for some portions of Alaska. Zerbini

et al.

(2006) estimated the coastal population between Kenai Fjords and the Aleutian Islands at 1,233 animals.

During Cook Inlet-wide aerial surveys conducted from 1993 to 2004, minke whales were encountered only twice (1998, 1999), both times off Anchor Point 16 miles northwest of Homer. A minke whale was also reported off Cape Starichkof in 2011 (A. Holmes, pers. comm.) and 2013 (E. Fernandez and C. Hesselbach, pers. comm.), suggesting this location is regularly used by minke whales, including during the winter. Recently, several minke whales were recorded off Cape Starichkof in early summer 2013 during exploratory drilling conducted there (Owl Ridge 2014). There are no records north of Cape Starichkof, and this species is unlikely to be seen in upper Cook Inlet. There is a chance of encountering this whale during seismic operations along the Kenai Peninsula in lower Cook Inlet.

Gray Whale (Eschrichtius robustus)

Numbers of gray whales in Cook Inlet are small compared to the overall population (18,017 individuals). However, Apache marine mammal observers recorded nine sightings of nine individuals (including possible resights of the same animals) from May-July 2012. Of those sightings, seven were observed from project vessels, and two were observed from land-based observation stations. The eastern North Pacific gray whales observed in Cook Inlet are likely migrating to summer feeding grounds in the Bering, Chukchi, and Beaufort Seas, though a small number feed along the coast between Kodiak Island and northern California (Matkin, 2009; Carretta

et al.,

2014). NMFS aerial surveys flown annually in June have not sighted a gray whale during survey season since 2001. Occurrences in the seismic survey area (especially in the upper parts of the Inlet) are expected to be low.

Two species of pinnipeds may be encountered in Cook Inlet: Harbor seal and Steller sea lion.

Harbor Seal (Phoca vitulina)

Harbor seals inhabit the coastal and estuarine waters of Cook Inlet. Historically, harbor seals have been more abundant in lower Cook Inlet than in upper Cook Inlet (Rugh

et al.,

2005a,b). Harbor seals are non-migratory; their movements are associated with tides, weather, season, food availability, and reproduction. The major haulout sites for harbor seals are located in lower Cook Inlet, and their presence in the upper inlet coincides with seasonal runs of prey species. For example, harbor seals are commonly observed along the Susitna River and other tributaries along upper Cook Inlet during the eulachon and salmon migrations (NMFS, 2003). During aerial surveys of upper Cook Inlet in 2001, 2002, and 2003, harbor seals were observed 24 to 96 km (15 to 60 mi) south-southwest of Anchorage at the Chickaloon, Little Susitna, Susitna, Ivan, McArthur, and Beluga Rivers (Rugh

et al.,

2005). NMFS aerial surveys flown in June have reported sightings ranging from 956 to 2037 harbor seals over the course of surveys from 2000 to 2012. Apache aerial observers recorded approximately 900 harbor seals north of the Forelands in 2012 (Lomac-MacNair

et al.,

2013). Moreover, preliminary reports from Apache's 2014 vessel, aerial, and land observations suggest harbor seals may be more abundant north of the Forelands than previously understood. During the 2D test program in March 2011, two harbor seals were observed by vessel-based PSOs. On March 25, 2011, one harbor seal was observed approximately 400 m (0.2 mi) from the

M/V Miss Diane.

At the time of the observation, the vessel was operating the positioning pinger, and PSOs instructed the operator to implement a shut-down. The pinger was shut down for 30 minutes while PSOs monitored the area and re-started the device when the animal was not sighted again during the 30 minute site clearing protocol. No unusual behaviors were reported during the time the animal was observed. The second harbor seal was observed on March 26, 2011, by vessel-based PSO onboard the

M/V Dreamcatcher

approximately 4,260 m (2.6 mi) from the source vessel, which was operating the 10 in

3

airgun at the time. NMFS and Apache do not anticipate encountering large aggregations of seals (the closest known haulout site to the action area is located on Kalgin Island, which is approximately 22 km [14 mi] south of the McArthur River), but we do expect to see individual harbor seals (Boveng

et al.,

2011); especially during large fish runs in the various rivers draining into Cook Inlet.

Important harbor seal life functions, such as breeding and molting may occur within portions of Apache's survey area in June and August, but the co-occurrence is expected to be minimal. From November through January, harbor seals leave Cook Inlet to forage in Shelikof Strait (Boveng

et al.,

2007).

Steller Sea Lion (Eumetopia jubatus)

Two separate stocks of Steller sea lions are recognized within U.S. waters: An eastern DPS, which includes animals east of Cape Suckling, Alaska; and a western DPS, which includes animals west of Cape Suckling (NMFS, 2008). Individuals in Cook Inlet are considered part of the western DPS, which is listed as endangered under the ESA.

Regional variation in trends in Steller sea lion pup counts in 2000-2012 is similar to that of non-pup counts (Johnson and Fritz, 2014). Overall, there is strong evidence that pup counts in the western stock in Alaska increased (1.45 percent annually). Between 2004 and 2008, Alaska western non-pup counts increased only 3%: Eastern Gulf of Alaska (Prince William Sound area) counts were higher and Kenai Peninsula through Kiska Island counts were stable, but western Aleutian counts continued to decline. Johnson and Fritz (2014) analyzed western Steller sea lion population trends in Alaska and noted that there was strong evidence that non-pup counts in the western stock in Alaska increased between 2000 and 2012 (average rate of 1.67 percent annually). However, there continues to be considerable regional variability in recent trends across the range in Alaska, with strong evidence of a positive trend east of Samalga Pass and strong evidence of a decreasing trend to the west (Allen and Angliss, 2014).

Steller sea lions primarily occur in lower, rather than upper Cook Inlet and are rarely sighted north of Nikiski on the Kenai Peninsula. NMFS aerial surveys conducted in June 2000-2012, primarily in lower Cook Inlet, indicated presence of 0 to 104 Steller sea lions. Haul-outs and rookeries are located near, but outside of Cook Inlet at Gore Point, Elizabeth Island, Perl Island, and Chugach Island (NMFS, 2008). No Steller sea lion haul-outs or rookeries are located in the vicinity of the seismic survey. Furthermore, no sightings of Steller sea lions were reported by Apache during the 2D test program in March 2011. During the 3D seismic survey, one Steller sea lion was observed from the

M/V Dreamcatcher

on August 18, 2012, during a period

when the air guns were not active. Although Apache has requested takes of Steller sea lions, Steller sea lions would be rare in the action area during seismic survey operations.

Apache's application contains more information on the status, distribution, seasonal distribution, and abundance of each of the species under NMFS jurisdiction mentioned in this document. Please refer to the application for that information (see

ADDRESSES

). Additional information can also be found in the NMFS Stock Assessment Reports (SAR). The Alaska 2014 SAR is available on the Internet at:

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

Potential Effects of the Specified Activity on Marine Mammals

This section includes a summary and discussion of the ways that components (

e.g.,

seismic airgun operations, vessel movement) of the specified activity, including mitigation, may impact marine mammals. The “Estimated Take by Incidental Harassment” section later in this document will include a quantitative analysis of the number of individuals that are expected to be taken by this activity. The “Negligible Impact Analysis” section will include the analysis of how this specific activity will impact marine mammals and will consider the content of this section, the “Estimated Take by Incidental Harassment” section, the “Mitigation” section, and the “Anticipated Effects on Marine Mammal Habitat” section to draw conclusions regarding the likely impacts of this activity on the reproductive success or survivorship of individuals and from that on the affected marine mammal populations or stocks.

Operating active acoustic sources, such as airgun arrays, has the potential for adverse effects on marine mammals. The majority of anticipated impacts would be from the use of acoustic sources.

Acoustic Impacts

When considering the influence of various kinds of sound on the marine environment, it is necessary to understand that different kinds of marine life are sensitive to different frequencies of sound. Based on available behavioral data, audiograms have been derived using auditory evoked potentials, anatomical modeling, and other data. Southall

et al.

(2007) designate “functional hearing groups” for marine mammals and estimate the lower and upper frequencies of functional hearing of the groups. The functional groups and the associated frequencies are indicated below (note that animals are less sensitive to sounds at the outer edge of their functional range and most sensitive to sounds of frequencies within a smaller range somewhere in the middle of their functional hearing range):

• Low frequency cetaceans (13 species of mysticetes): functional hearing is estimated to occur between approximately 7 Hz and 30 kHz;

• Mid-frequency cetaceans (32 species of dolphins, six species of larger toothed whales, and 19 species of beaked and bottlenose whales): Functional hearing is estimated to occur between approximately 150 Hz and 160 kHz;

• High frequency cetaceans (eight species of true porpoises, six species of river dolphins, Kogia, the franciscana, and four species of cephalorhynchids): Functional hearing is estimated to occur between approximately 200 Hz and 180 kHz;

• Phocid pinnipeds in Water: Functional hearing is estimated to occur between approximately 75 Hz and 100 kHz; and

• Otariid pinnipeds in Water: Functional hearing is estimated to occur between approximately 100 Hz and 40 kHz.

As mentioned previously in this document, nine marine mammal species (seven cetacean and two pinniped species) are likely to occur in the seismic survey area. Of the four cetacean species likely to occur in Apache's project area, one is classified as a low-frequency cetacean (gray whale), two are classified as mid-frequency cetaceans (

i.e.,

beluga and killer whales), and one is classified as a high-frequency cetacean (

i.e.,

harbor porpoise) (Southall

et al.,

2007). Of the two pinniped species likely to occur in Apache's project area, one is classified as a phocid (

i.e.,

harbor seal), and one is classified as an otariid (

i.e.,

Steller sea lion). A species functional hearing group is a consideration when we analyze the effects of its exposure to different frequencies of sound.

1. Potential Effects of Airgun Sounds on Marine Mammals

The effects of sounds from airgun pulses might include one or more of the following: Tolerance, masking of natural sounds, behavioral disturbance, temporary or permanent hearing threshold shifts, and non-auditory effects (Richardson

et al.,

1995). As outlined in previous NMFS documents, the effects of noise on marine mammals are highly variable, often depending on species and contextual factors (based on Richardson

et al.,

1995).

Tolerance:

Numerous studies have shown that pulsed sounds from air guns are often readily detectable in the water at distances of many kilometers. Numerous studies have also shown that marine mammals at distances more than a few kilometers from operating survey vessels often show no apparent response. That is often true even in cases when the pulsed sounds must be readily audible to the animals based on measured received levels and the hearing sensitivity of that mammal group. In general, pinnipeds and small odontocetes (toothed whales) seem to be more tolerant of exposure to air gun pulses than baleen whales. Although various toothed whales, and (less frequently) pinnipeds have been shown to react behaviorally to airgun pulses under some conditions, at other times, mammals of both types have shown no overt reactions. Weir (2008) observed marine mammal responses to seismic pulses from a 24 airgun array firing a total volume of either 5,085 in

3

or 3,147 in

3

in Angolan waters between August 2004 and May 2005. Weir recorded a total of 207 sightings of humpback whales (n = 66), sperm whales (n = 124), and Atlantic spotted dolphins (n = 17) and reported that there were no significant differences in encounter rates (sightings/hr) for humpback and sperm whales according to the airgun array's operational status (

i.e.,

active versus silent).

Behavioral Disturbance:

Marine mammals may behaviorally respond when exposed to anthropogenic noise. These behavioral reactions are often shown as: Changing durations of surfacing and dives, number of blows per surfacing, or moving direction and/or speed; reduced/increased vocal activities; changing/cessation of certain behavioral activities (such as socializing or feeding); visible startle response or aggressive behavior (such as tail/fluke slapping or jaw clapping); avoidance of areas where noise sources are located; and/or flight responses (

e.g.,

pinnipeds flushing into water from haulouts or rookeries).

The biological significance of many of these behavioral disturbances is difficult to predict. The consequences of behavioral modification to individual fitness can range from none up to potential changes to growth, survival, or reproduction, depending on the context, duration, and degree of behavioral modification. Examples of behavioral modifications that could impact growth, survival or reproduction include: Drastic changes in diving/surfacing/swimming patterns that lead to stranding (such as those associated with beaked whale strandings related to

exposure to military mid-frequency tactical sonar); longer-term abandonment of habitat that is specifically important for feeding, reproduction, or other critical needs, or significant disruption of feeding or social interaction resulting in substantive energetic costs, inhibited breeding, or prolonged or permanent cow-calf separation.

The likelihood and severity of behavioral disturbance from anthropogenic noise depends on both external factors (characteristics of noise sources and their paths) and the receiving animals (hearing, motivation, experience, demography, context of the exposure) and is also difficult to predict (Southall

et al.,

2007).

Toothed whales. Few systematic data are available describing reactions of toothed whales to noise pulses. However, systematic work on sperm whales (Tyack

et al.,

2003) has yielded an increasing amount of information about responses of various odontocetes to seismic surveys based on monitoring studies (

e.g.,

Stone, 2003; Smultea

et al.,

2004; Moulton and Miller, 2005). Stone

et al.

(2003) reported reduced sighting rates of small odontocetes during periods of shooting during seismic surveys with large airgun arrays. Moulton and Miller (2004) also found that the range of audibility of seismic pules for mid-sized odontecetes was largely underestimated by models.

Seismic operators and marine mammal observers sometimes see dolphins and other small toothed whales near operating airgun arrays, but, in general, there seems to be a tendency for most delphinids to show some avoidance of seismic vessels operating large airgun systems. However, some dolphins seem to be attracted to the seismic vessel and floats, and some ride the bow wave of the seismic vessel even when large arrays of airguns are firing. Nonetheless, there have been indications that small toothed whales sometimes move away or maintain a somewhat greater distance from the vessel when a large array of airguns is operating than when it is silent (

e.g.,

Goold, 1996a,b,c; Calambokidis and Osmek, 1998; Stone, 2003). The beluga may be a species that (at least in certain geographic areas) shows long-distance avoidance of seismic vessels. Aerial surveys during seismic operations in the southeastern Beaufort Sea recorded much lower sighting rates of beluga whales within 10-20 km (6.2-12.4 mi) of an active seismic vessel. These results were consistent with the low number of beluga sightings reported by observers aboard the seismic vessel, indicating that belugas may avoid seismic operations at distances of 10-20 km (6.2-12.4 mi) (Miller

et al.,

2005).

Captive bottlenose dolphins and beluga whales exhibit changes in behavior when exposed to strong pulsed sounds similar in duration to those typically used in seismic surveys (Finneran

et al.,

2002, 2005). However, the animals tolerated high received levels of sound (pk-pk level >200 dB re 1 μPa) before exhibiting aversive behaviors.

Observers stationed on seismic vessels operating off the United Kingdom from 1997-2000 have provided data on the occurrence and behavior of various toothed whales exposed to seismic pulses (Stone, 2003; Gordon

et al.,

2004). Killer whales were found to be significantly farther from large airgun arrays during periods of shooting compared with periods of no shooting. The displacement of the median distance from the array was approximately 0.5 km (0.3 mi) or more. Killer whales also appear to be more tolerant of seismic shooting in deeper water (illustrating another example of the importance of context in predicting responses).

Reactions of toothed whales to large arrays of airguns are variable and, at least for delphinids, seem to be confined to a smaller radius than has been observed for mysticetes. However, based on the limited existing evidence, belugas should not necessarily be grouped with delphinids in the “less responsive” category.

Pinnipeds. Pinnipeds are not likely to show a strong avoidance reaction to the airgun sources used. Visual monitoring from seismic vessels has shown only slight (if any) avoidance of airguns by pinnipeds and only slight (if any) changes in behavior. Monitoring work in the Alaskan Beaufort Sea during 1996-2001 provided considerable information regarding the behavior of Arctic ice seals exposed to seismic pulses (Harris

et al.,

2001; Moulton and Lawson, 2002). These seismic projects usually involved arrays of 6 to 16 airguns with total displacement volumes of 560 to 1,500 in

3

. The combined results suggest that some seals avoid the immediate area around seismic vessels. In most survey years, ringed seal sightings tended to be farther away from the seismic vessel when the airguns were operating than when they were not (Moulton and Lawson, 2002). However, these avoidance movements were relatively small, on the order of 100 m (328 ft) to a few hundreds of meters, and many seals remained within 100-200 m (328-656 ft) of the trackline as the operating airgun array passed by. Seal sighting rates at the water surface were lower during airgun array operations than during no-airgun periods in each survey year except 1997. Similarly, seals are often very tolerant of pulsed sounds from seal-scaring devices (Mate and Harvey, 1987; Jefferson and Curry, 1994; Richardson

et al.,

1995a). However, initial telemetry work suggests that avoidance and other behavioral reactions by two other species of seals, grey and harbor seals, to small airgun sources may at times be stronger than evident to date from visual studies of pinniped reactions to airguns (Thompson

et al.,

1998). Even if reactions of the species occurring in the activity area are as strong as those evident in the telemetry study, reactions are expected to be confined to relatively small distances and durations, with no long-term effects on pinniped individuals or populations.

Masking:

Masking is the obscuring of sounds of interest by other sounds, often at similar frequencies. Marine mammals use acoustic signals for a variety of purposes, which differ among species, but include communication between individuals, navigation, foraging, reproduction, avoiding predators, and learning about their environment (Erbe and Farmer, 2000; Tyack, 2000). Masking, or auditory interference, generally occurs when sounds in the environment are louder than, and of a similar frequency to, auditory signals an animal is trying to receive. Masking is a phenomenon that affects animals trying to receive acoustic information about their environment, including sounds from other members of their species, predators, prey, and sounds that allow them to orient in their environment. Masking these acoustic signals can disturb the behavior of individual animals, groups of animals, or entire populations.

Masking occurs when anthropogenic sounds and signals (that the animal utilizes) overlap at both spectral and temporal scales. For the airgun sound generated from the seismic surveys, sound will consist of low frequency (under 500 Hz) pulses with extremely short durations (less than one second). Lower frequency man-made sounds are more likely to affect detection of potentially important natural sounds such as surf and prey noise, or communication calls for low frequency specialists. There is little concern regarding masking near the sound source due to the brief duration of these pulses and relatively longer silence between air gun shots (approximately 12 seconds). However, at long distances (over tens of kilometers away), due to multipath propagation and

reverberation, the durations of airgun pulses can be “stretched” to seconds with long decays (Madsen

et al.,

2006), and shorter intervals between pulses, although the intensity of the sound is greatly reduced.

This could affect communication signals used by low frequency mysticetes when they occur near the noise band and thus reduce the communication space of animals (

e.g.,

Clark

et al.,

2009) and cause increased stress levels (

e.g.,

Foote

et al.,

2004; Holt

et al.,

2009); however, few baleen whales are expected to occur within the action area. Marine mammals are thought to be able to compensate for masking by adjusting their acoustic behavior by shifting call frequencies, and/or increasing call volume and vocalization rates. For example, blue whales were found to increase call rates when exposed to seismic survey noise in the St. Lawrence Estuary (Di Iorio and Clark, 2010). The North Atlantic right whales (

Eubalaena glacialis

) exposed to high shipping noise increase call frequency (Parks

et al.,

2007), while some humpback whales respond to low-frequency active sonar playbacks by increasing song length (Miller

et al.,

2000). Additionally, beluga whales have been known to change their vocalizations in the presence of high background noise possibly to avoid masking calls (Au

et al.,

1985; Lesage

et al.,

1999; Scheifele

et al.,

2005). Although some degree of masking is inevitable when high levels of manmade broadband sounds are introduced into the sea, marine mammals have evolved systems and behavior that function to reduce the impacts of masking. Structured signals, such as the echolocation click sequences of small toothed whales, may be readily detected even in the presence of strong background noise because their frequency content and temporal features usually differ strongly from those of the background noise (Au and Moore, 1988, 1990). The components of background noise that are similar in frequency to the sound signal in question primarily determine the degree of masking of that signal.

Redundancy and context can also facilitate detection of weak signals. These phenomena may help marine mammals detect weak sounds in the presence of natural or manmade noise. Most masking studies in marine mammals present the test signal and the masking noise from the same direction. The sound localization abilities of marine mammals suggest that, if signal and noise come from different directions, masking would not be as severe as the usual types of masking studies might suggest (Richardson

et al.,

1995). The dominant background noise may be highly directional if it comes from a particular anthropogenic source such as a ship or industrial site. Directional hearing may significantly reduce the masking effects of these sounds by improving the effective signal-to-noise ratio. In the cases of higher frequency hearing by the bottlenose dolphin, beluga whale, and killer whale, empirical evidence confirms that masking depends strongly on the relative directions of arrival of sound signals and the masking noise (Penner

et al.,

1986; Dubrovskiy, 1990; Bain

et al.,

1993; Bain and Dahlheim, 1994). Toothed whales and probably other marine mammals as well, have additional capabilities besides directional hearing that can facilitate detection of sounds in the presence of background noise. There is evidence that some toothed whales can shift the dominant frequencies of their echolocation signals from a frequency range with a lot of ambient noise toward frequencies with less noise (Au

et al.,

1974, 1985; Moore and Pawloski, 1990; Thomas and Turl, 1990; Romanenko and Kitain, 1992; Lesage

et al.,

1999). A few marine mammal species are known to increase the source levels or alter the frequency of their calls in the presence of elevated sound levels (Dahlheim, 1987; Au, 1993; Lesage

et al.,

1993, 1999; Terhune, 1999; Foote

et al.,

2004; Parks

et al.,

2007, 2009; Di Iorio and Clark, 2009; Holt

et al.,

2009).

These data demonstrating adaptations for reduced masking pertain mainly to the very high frequency echolocation signals of toothed whales. There is less information about the existence of corresponding mechanisms at moderate or low frequencies or in other types of marine mammals. For example, Zaitseva

et al.

(1980) found that, for the bottlenose dolphin, the angular separation between a sound source and a masking noise source had little effect on the degree of masking when the sound frequency was 18 kHz, in contrast to the pronounced effect at higher frequencies. Directional hearing has been demonstrated at frequencies as low as 0.5-2 kHz in several marine mammals, including killer whales (Richardson

et al.,

1995a). This ability may be useful in reducing masking at these frequencies. In summary, high levels of sound generated by anthropogenic activities may act to mask the detection of weaker biologically important sounds by some marine mammals. This masking may be more prominent for lower frequencies. For higher frequencies, such as that used in echolocation by toothed whales, several mechanisms are available that may allow them to reduce the effects of such masking.

Threshold Shift (noise-induced loss of hearing)

—When animals exhibit reduced hearing sensitivity (

i.e.,

sounds must be louder for an animal to detect them) following exposure to loud and/or persistent sound, it is referred to as a noise-induced threshold shift (TS). An animal can experience temporary threshold shift (TTS) or permanent threshold shift (PTS). TTS can last from minutes or hours to days (

i.e.,

there is complete recovery), can occur in specific frequency ranges (

i.e.,

an animal might only have a temporary loss of hearing sensitivity between the frequencies of 1 and 10 kHz), and can be of varying amounts (for example, an animal's hearing sensitivity might be reduced initially by only 6 dB or reduced by 30 dB). PTS is permanent, but some recovery is possible. PTS can also occur in a specific frequency range and amount as mentioned above for TTS.

The following physiological mechanisms are thought to play a role in inducing auditory TS: Effects to sensory hair cells in the inner ear that reduce their sensitivity, modification of the chemical environment within the sensory cells, residual muscular activity in the middle ear, displacement of certain inner ear membranes, increased blood flow, and post-stimulatory reduction in both efferent and sensory neural output (Southall

et al.,

2007). The amplitude, duration, frequency, temporal pattern, and energy distribution of sound exposure all can affect the amount of associated TS and the frequency range in which it occurs. As amplitude and duration of sound exposure increase, so, generally, does the amount of TS, along with the recovery time. For intermittent sounds, less TS could occur than compared to a continuous exposure with the same energy (some recovery could occur between intermittent exposures depending on the duty cycle between sounds) (Kryter

et al.,

1966; Ward, 1997). For example, one short but loud (higher SPL) sound exposure may induce the same impairment as one longer but softer sound, which in turn may cause more impairment than a series of several intermittent softer sounds with the same total energy (Ward, 1997). Additionally, though TTS is temporary, prolonged exposure to sounds strong enough to elicit TTS, or shorter-term exposure to sound levels well above the TTS threshold, can cause PTS, at least in terrestrial mammals (Kryter, 1985). In the case of the seismic

survey, animals are not expected to be exposed to levels high enough or durations long enough to result in PTS.

PTS is considered auditory injury (Southall

et al.,

2007). Irreparable damage to the inner or outer cochlear hair cells may cause PTS; however, other mechanisms are also involved, such as exceeding the elastic limits of certain tissues and membranes in the middle and inner ears and resultant changes in the chemical composition of the inner ear fluids (Southall

et al.,

2007).

Although the published body of scientific literature contains numerous theoretical studies and discussion papers on hearing impairments that can occur with exposure to a loud sound, only a few studies provide empirical information on the levels at which noise-induced loss in hearing sensitivity occurs in nonhuman animals. For marine mammals, published data are limited to the captive bottlenose dolphin, beluga, harbor porpoise, and Yangtze finless porpoise (Finneran

et al.,

2000, 2002, 2003, 2005, 2007, 2010a, 2010b; Finneran and Schlundt, 2010; Lucke

et al.,

2009; Mooney

et al.,

2009a, 2009b; Popov

et al.,

2011a, 2011b; Kastelein

et al.,

2012a; Schlundt

et al.,

2000; Nachtigall

et al.,

2003, 2004). For pinnipeds in water, data are limited to measurements of TTS in harbor seals, an elephant seal, and California sea lions (Kastak

et al.,

1999, 2005; Kastelein

et al.,

2012b).

Marine mammal hearing plays a critical role in communication with conspecifics, and interpretation of environmental cues for purposes such as predator avoidance and prey capture. Depending on the degree (elevation of threshold in dB), duration (

i.e.,

recovery time), and frequency range of TTS, and the context in which it is experienced, TTS can have effects on marine mammals ranging from discountable to serious (similar to those discussed in auditory masking, below). For example, a marine mammal may be able to readily compensate for a brief, relatively small amount of TTS in a non-critical frequency range that occurs during a time where ambient noise is lower and there are not as many competing sounds present. Alternatively, a larger amount and longer duration of TTS sustained during time when communication is critical for successful mother/calf interactions could have more serious impacts. Similarly, depending on the degree and frequency range, the effects of PTS on an animal could range in severity, although it is considered generally more serious because it is a permanent condition. Of note, reduced hearing sensitivity as a simple function of aging has been observed in marine mammals, as well as humans and other taxa (Southall

et al.,

2007), so we can infer that strategies exist for coping with this condition to some degree, though likely not without cost.

Given the higher level of sound necessary to cause PTS as compared with TTS, it is considerably less likely that PTS would occur during the seismic surveys in Cook Inlet. Cetaceans generally avoid the immediate area around operating seismic vessels, as do some other marine mammals. Some pinnipeds show avoidance reactions to airguns, but their avoidance reactions are generally not as strong or consistent as those of cetaceans, and occasionally they seem to be attracted to operating seismic vessels (NMFS, 2010).

Non-Auditory Physical Effects:

Non-auditory physical effects might occur in marine mammals exposed to strong underwater pulsed sound. Possible types of non-auditory physiological effects or injuries that theoretically might occur in mammals close to a strong sound source include stress, neurological effects, bubble formation, and other types of organ or tissue damage. Some marine mammal species (

i.e.,

beaked whales) may be especially susceptible to injury and/or stranding when exposed to strong pulsed sounds.

Classic stress responses begin when an animal's central nervous system perceives a potential threat to its homeostasis. That perception triggers stress responses regardless of whether a stimulus actually threatens the animal; the mere perception of a threat is sufficient to trigger a stress response (Moberg, 2000; Sapolsky

et al.,

2005; Seyle, 1950). Once an animal's central nervous system perceives a threat, it mounts a biological response or defense that consists of a combination of the four general biological defense responses: Behavioral responses; autonomic nervous system responses; neuroendocrine responses; or immune responses.

In the case of many stressors, an animal's first and most economical (in terms of biotic costs) response is behavioral avoidance of the potential stressor or avoidance of continued exposure to a stressor. An animal's second line of defense to stressors involves the sympathetic part of the autonomic nervous system and the classical “fight or flight” response, which includes the cardiovascular system, the gastrointestinal system, the exocrine glands, and the adrenal medulla to produce changes in heart rate, blood pressure, and gastrointestinal activity that humans commonly associate with “stress.” These responses have a relatively short duration and may or may not have significant long-term effects on an animal's welfare.

An animal's third line of defense to stressors involves its neuroendocrine or sympathetic nervous systems; the system that has received the most study has been the hypothalmus-pituitary-adrenal system (also known as the HPA axis in mammals or the hypothalamus-pituitary-interrenal axis in fish and some reptiles). Unlike stress responses associated with the autonomic nervous system, virtually all neuroendocrine functions that are affected by stress—including immune competence, reproduction, metabolism, and behavior—are regulated by pituitary hormones. Stress-induced changes in the secretion of pituitary hormones have been implicated in failed reproduction (Moberg, 1987; Rivier, 1995), altered metabolism (Elasser

et al.,

2000), reduced immune competence (Blecha, 2000), and behavioral disturbance. Increases in the circulation of glucocorticosteroids (cortisol, corticosterone, and aldosterone in marine mammals; see Romano

et al.,

2004) have been equated with stress for many years.

The primary distinction between stress (which is adaptive and does not normally place an animal at risk) and distress is the biotic cost of the response. During a stress response, an animal uses glycogen stores that can be quickly replenished once the stress is alleviated. In such circumstances, the cost of the stress response would not pose a risk to the animal's welfare. However, when an animal does not have sufficient energy reserves to satisfy the energetic costs of a stress response, energy resources must be diverted from other biotic functions, which impair those functions that experience the diversion. For example, when mounting a stress response diverts energy away from growth in young animals, those animals may experience stunted growth. When mounting a stress response diverts energy from a fetus, an animal's reproductive success and fitness will suffer. In these cases, the animals will have entered a pre-pathological or pathological state which is called “distress” (sensu Seyle, 1950) or “allostatic loading” (sensu McEwen and Wingfield, 2003). This pathological state will last until the animal replenishes its biotic reserves sufficient to restore normal function. Note that these examples involved a long-term (days or weeks) stress response due to exposure to stimuli.

Relationships between these physiological mechanisms, animal behavior, and the costs of stress

responses have also been documented fairly well through controlled experiment; because this physiology exists in every vertebrate that has been studied, it is not surprising that stress responses and their costs have been documented in both laboratory and free-living animals (for examples see, Holberton

et al.,

1996; Hood

et al.,

1998; Jessop

et al.,

2003; Krausman

et al.,

2004; Lankford

et al.,

2005; Reneerkens

et al.,

2002; Thompson and Hamer, 2000). Although no information has been collected on the physiological responses of marine mammals to anthropogenic sound exposure, studies of other marine animals and terrestrial animals would lead us to expect some marine mammals to experience physiological stress responses and, perhaps, physiological responses that would be classified as “distress” upon exposure to anthropogenic sounds.

For example, Jansen (1998) reported on the relationship between acoustic exposures and physiological responses that are indicative of stress responses in humans (

e.g.,

elevated respiration and increased heart rates). Jones (1998) reported on reductions in human performance when faced with acute, repetitive exposures to acoustic disturbance. Trimper

et al.

(1998) reported on the physiological stress responses of osprey to low-level aircraft noise while Krausman

et al.

(2004) reported on the auditory and physiology stress responses of endangered Sonoran pronghorn to military overflights. Smith

et al.

(2004a, 2004b) identified noise-induced physiological transient stress responses in hearing-specialist fish (

i.e.,

goldfish) that accompanied short- and long-term hearing losses. Welch and Welch (1970) reported physiological and behavioral stress responses that accompanied damage to the inner ears of fish and several mammals.

Hearing is one of the primary senses marine mammals use to gather information about their environment and communicate with conspecifics. Although empirical information on the effects of sensory impairment (TTS, PTS, and acoustic masking) on marine mammals remains limited, we assume that reducing a marine mammal's ability to gather information about its environment and communicate with other members of its species would induce stress, based on data that terrestrial animals exhibit those responses under similar conditions (NRC, 2003) and because marine mammals use hearing as their primary sensory mechanism. Therefore, we assume that acoustic exposures sufficient to trigger onset PTS or TTS would be accompanied by physiological stress responses. However, marine mammals also might experience stress responses at received levels lower than those necessary to trigger onset TTS. Based on empirical studies of the time required to recover from stress responses (Moberg, 2000), NMFS also assumes that stress responses could persist beyond the time interval required for animals to recover from TTS and might result in pathological and pre-pathological states that would be as significant as behavioral responses to TTS. Resonance effects (Gentry, 2002) and direct noise-induced bubble formations (Crum

et al.,

2005) are implausible in the case of exposure to an impulsive broadband source like an airgun array. If seismic surveys disrupt diving patterns of deep-diving species, this might result in bubble formation and a form of the bends, as speculated to occur in beaked whales exposed to sonar. However, there is no specific evidence of this upon exposure to airgun pulses, and no beaked whale species occur in Apache's seismic survey area.

In general, very little is known about the potential for strong, anthropogenic underwater sounds to cause non-auditory physical effects in marine mammals. Such effects, if they occur at all, would presumably be limited to short distances and to activities that extend over a prolonged period. The available data do not allow identification of a specific exposure level above which non-auditory effects can be expected (Southall

et al.,

2007) or any meaningful quantitative predictions of the numbers (if any) of marine mammals that might be affected in those ways. There is no definitive evidence that any of these effects occur even for marine mammals in close proximity to large arrays of airguns. In addition, marine mammals that show behavioral avoidance of seismic vessels, including belugas and some pinnipeds, are especially unlikely to incur non-auditory impairment or other physical effects. Therefore, it is unlikely that such effects would occur during Apache's surveys given the brief duration of exposure and the planned monitoring and mitigation measures described later in this document.

Stranding and Mortality:

Marine mammals close to underwater detonations of high explosives can be killed or severely injured, and the auditory organs are especially susceptible to injury (Ketten

et al.,

1993; Ketten 1995). Airgun pulses are less energetic and their peak amplitudes have slower rise times. To date, there is no evidence that serious injury, death, or stranding by marine mammals can occur from exposure to air gun pulses, even in the case of large air gun arrays.

However, in past IHA notices for seismic surveys, commenters have referenced two stranding events allegedly associated with seismic activities, one off Baja California and a second off Brazil. NMFS has addressed this concern several times, including in the

Federal Register

notice announcing the IHA for Apache Alaska's first seismic survey in 2012. Readers are encouraged to review NMFS's response to comments on this matter found in 69 FR 74905 (December 14, 2004), 71 FR 43112 (July 31, 2006), 71 FR 50027 (August 24, 2006), 71 FR 49418 (August 23, 2006), and 77 FR 27720 (May 11, 2012).

Beluga whale strandings in Cook Inlet are not uncommon; however, these events often coincide with extreme tidal fluctuations (“spring tides”) or killer whale sightings (Shelden

et al.,

2003). For example, in August 2012, a group of Cook Inlet beluga whales stranded in the mud flats of Turnagain Arm during low tide and were able to swim free with the flood tide. No strandings or marine mammals in distress were observed during the 2D test survey conducted by Apache in March 2011, and none were reported by Cook Inlet inhabitants. Based on our consideration of the best available information, NMFS does not expect any marine mammals will incur serious injury or mortality in Cook Inlet or strand as a result of the seismic survey.

2. Potential Effects From Pingers on Marine Mammals

Active acoustic sources other than the airguns will be used for Apache's 5-year oil and gas exploration seismic survey program in Cook Inlet. The specifications for the pingers (source levels and frequency ranges) were provided in the FR notice of the proposed rule (80 FR 9510). In general, pingers are known to cause behavioral disturbance and are commonly used to deter marine mammals from commercial fishing gear or fish farms.

3. Potential Effects From Aircraft Noise on Marine Mammals

Apache plans to utilize aircraft to conduct aerial surveys near river mouths in order to identify locations or congregations of beluga whales and other marine mammals prior to the commencement of operations. The aircraft will not be used every day but will be used for surveys near river mouths. Survey aircraft will fly at an altitude of about 300 m (1,000 ft) when practicable and when weather conditions allow. In the event of a

marine mammal sighting, aircraft will try to maintain a radial distance of 457 m (1,500 ft) from the marine mammal(s). Aircraft will avoid approaching marine mammals from head-on, flying over or passing the shadow of the aircraft over the marine mammals.

Studies on the reactions of cetaceans to aircraft show little negative response (Richardson

et al.,

1995). In general, reactions range from sudden dives and turns and are typically found to decrease if the animals are engaged in feeding or social behavior. Whales with calves or in confined waters may show more of a response. There has been little or no evidence of marine mammals in the Arctic responding to aircraft at altitudes greater than about 300 m (1,000 ft), during the past three decades. (NMFS, unpublished data). No change in beluga swim directions or other noticeable reactions have been observed during the Cook Inlet aerial surveys flown from 183 to 244 m (600 to 800 ft) since 1993 (

e.g.,

Rugh

et al.,

2000). Therefore, NMFS expects no effects on beluga whales or other cetaceans due to aerial surveys associated with this action.

The majority of observations of pinnipeds reacting to aircraft noise are associated with animals hauled out on land or ice. There are few data describing the reactions of pinnipeds in water to aircraft (Richardson

et al.,

1995). In the presence of aircraft, pinnipeds hauled out for pupping or molting generally became alert and then rushed or slipped (when on ice) into the water. Stampedes often result from this response and may increase pup mortality due to crushing or an increased rate of pup abandonment. The greatest reactions from hauled-out pinnipeds were observed when low flying aircraft passed directly above the animal(s) (Richardson

et al.,

1995). Although noise associated with aircraft activity could cause hauled out pinnipeds to rush into the water, there are no known haul out sites in the vicinity of the survey site. Therefore, the operation of aircraft during the seismic survey is not expected to result in the harassment of pinnipeds. To minimize the noise generated by aircraft, Apache will follow NMFS's Marine Mammal Viewing Guidelines and Regulations found on the Internet at:

http://www.alaskafisheries.noaa.gov/protectedresources/mmv/guide.htm.

4. Vessel Impacts

Vessel activity and noise associated with vessel activity will temporarily increase in the action area during Apache's seismic survey as a result of the operation of nine vessels. To minimize the effects of vessels and noise associated with vessel activity, Apache will follow NMFS's Marine Mammal Viewing Guidelines and Regulations and will alter heading or speed if a marine mammal gets too close to a vessel. In addition, vessels will be operating at slow speed (2-4 knots) when conducting surveys and in a purposeful manner to and from work sites in as direct a route as possible. Marine mammal monitoring observers and passive acoustic devices will alert vessel captains as animals are detected to ensure safe and effective measures are applied to avoid coming into direct contact with marine mammals. Therefore, NMFS neither anticipates nor authorizes takes of marine mammals from ship strikes.

Odontocetes, such as beluga whales, killer whales, and harbor porpoises, often show tolerance to vessel activity; however, they may react at long distances if they are confined by ice, shallow water, or were previously harassed by vessels (Richardson

et al.,

1995). Beluga whale response to vessel noise varies greatly from tolerance to extreme sensitivity depending on the activity of the whale and previous experience with vessels (Richardson

et al.,

1995). Reactions to vessels depend on whale activities and experience, habitat, boat type, and boat behavior (Richardson

et al.,

1995) and may include behavioral responses, such as altered headings or avoidance (Blane and Jaakson, 1994; Erbe and Farmer, 2000); fast swimming; changes in vocalizations (Lesage

et al.,

1999; Scheifele

et al.,

2005); and changes in dive, surfacing, and respiration patterns.

There are few data published on pinniped responses to vessel activity, and most of the information is anecdotal (Richardson

et al.,

1995). Generally, sea lions in water show tolerance to close approaching vessels and sometimes show interest in fishing vessels. They are less tolerant when hauled out on land; however, they rarely react unless the vessel approaches within 100-200 m (330-660 ft; reviewed in Richardson

et al.,

1995).

5. Entanglement

Although some of Apache's equipment contains cables or lines, the risk of entanglement is extremely remote. The material used by Apache and the amount of slack in lines is not anticipated to allow for marine mammal entanglements. No incidents of entanglement have been reported from any seismic operators in Cook Inlet, and therefore injury or mortality from entanglement is not anticipated.

Anticipated Effects on Marine Mammal Habitat

This section describes the potential impacts to marine mammal habitat from the specified activity. Because the marine mammals in the area feed on fish and/or invertebrates there is also information on the species typically preyed upon by the marine mammals in the area. As noted earlier, upper Cook Inlet is an important feeding and calving area for the Cook Inlet beluga whale, and critical habitat has been designated for this species in the seismic survey area.

Common Marine Mammal Prey in the Project Area

Fish are the primary prey species for marine mammals in upper Cook Inlet. Beluga whales feed on a variety of fish, shrimp, squid, and octopus (Burns and Seaman, 1986). Common prey species in Cook Inlet include salmon, eulachon and cod. Harbor seals feed on fish such as pollock, cod, capelin, eulachon, Pacific herring, and salmon, as well as a variety of benthic species, including crabs, shrimp, and cephalopods. Harbor seals are also opportunistic feeders with their diet varying with season and location. The preferred diet of the harbor seal in the Gulf of Alaska consists of pollock, octopus, capelin, eulachon, and Pacific herring (Calkins, 1989). Other prey species include cod, flat fishes, shrimp, salmon, and squid (Hoover, 1988). Harbor porpoises feed primarily on Pacific herring, cod, whiting (hake), pollock, squid, and octopus (Leatherwood

et al.,

1982). In the upper Cook Inlet area, harbor porpoise feed on squid and a variety of small schooling fish, which would likely include Pacific herring and eulachon (Bowen and Siniff, 1999; NMFS, unpublished data). Killer whales feed on either fish or other marine mammals depending on genetic type (resident versus transient respectively). Killer whales in Knik Arm are typically the transient type (Shelden

et al.,

2003) and feed on beluga whales and other marine mammals, such as harbor seal and harbor porpoise. The Steller sea lion diet consists of a variety of fishes (capelin, cod, herring, mackerel, pollock, rockfish, salmon, sand lance, etc.), bivalves, squid, octopus, and gastropods.

Potential Impacts of Sound on Prey Species

With regard to fish as a prey source for cetaceans and pinnipeds, fish are known to hear and react to sounds and to use sound to communicate (Tavolga

et al.,

1981) and possibly avoid

predators (Wilson and Dill, 2002). Experiments have shown that fish can sense both the strength and direction of sound (Hawkins, 1981). Primary factors determining whether a fish can sense a sound signal, and potentially react to it, are the frequency of the signal and the strength of the signal in relation to the natural background sound level.

Fishes have evolved a diversity of sound generating organs and acoustic signals of various temporal and spectral contents. Fish sounds vary in structure, depending on the mechanism used to produce them (Hawkins, 1993). Generally, fish sounds are predominantly composed of low frequencies (less than 3 kHz). Fishes produce sounds that are associated with behaviors that include territoriality, mate search, courtship, and aggression. It has also been speculated that sound production may provide the means for long distance communication and communication under poor underwater visibility conditions (Zelick

et al.,

1999), although the fact that fish communicate at low-frequency sound levels where the masking effects of ambient noise are naturally highest suggests that very long distance communication would rarely be possible.

Since objects in the water scatter sound, fish are able to detect these objects through monitoring the ambient noise. Therefore, fish are probably able to detect prey, predators, conspecifics, and physical features by listening to environmental sounds (Hawkins, 1981). There are two sensory systems that enable fish to monitor the vibration-based information of their surroundings. The two sensory systems, the inner ear and the lateral line, constitute the acoustico-lateralis system.

Although the hearing sensitivities of very few fish species have been studied to date, it is becoming obvious that the intra- and inter-specific variability is considerable (Coombs, 1981). Nedwell

et al.

(2004) compiled and published available fish audiogram information. A noninvasive electrophysiological recording method known as auditory brainstem response is now commonly used in the production of fish audiograms (Yan, 2004). Popper and Carlson (1998) and the Navy (2001) found that fish generally perceive underwater sounds in the frequency range of 50-2,000 Hz, with peak sensitivities below 800 Hz. Even though some fish are able to detect sounds in the ultrasonic frequency range, the hearing thresholds at these higher frequencies tend to be considerably higher than those at the lower end of the auditory hearing frequency range.

Fish are sensitive to underwater impulsive sounds due to swim bladder resonance. As the pressure wave passes through a fish, the swim bladder is rapidly squeezed as the high pressure wave, and then the under pressure component of the wave, passes through the fish. The swim bladder may repeatedly expand and contract at the high sound pressure levels, creating pressure on the internal organs surrounding the swim bladder.

Literature relating to the impacts of sound on marine fish species can be divided into the following categories: (1) Pathological effects; (2) physiological effects; and (3) behavioral effects. Pathological effects include lethal and sub-lethal physical damage to fish; physiological effects include primary and secondary stress responses; and behavioral effects include changes in exhibited behaviors of fish. Behavioral changes might be a direct reaction to a detected sound or a result of the anthropogenic sound masking natural sounds that the fish normally detect and to which they respond. The three types of effects are often interrelated in complex ways. For example, some physiological and behavioral effects could potentially lead to the ultimate pathological effect of mortality. Hastings and Popper (2005) reviewed what is known about the effects of sound on fishes and identified studies needed to address areas of uncertainty relative to measurement of sound and the responses of fishes. Popper

et al.

(2003/2004) also published a paper that reviews the effects of anthropogenic sound on the behavior and physiology of fishes.

The level of sound at which a fish will react or alter its behavior is usually well above the detection level. Fish have been found to react to sounds when the sound level increased to about 20 dB above the detection level of 120 dB (Ona, 1988); however, the response threshold can depend on the time of year and the fish's physiological condition (Engas

et al.,

1993). In general, fish react more strongly to pulses of sound rather than a continuous signal (Blaxter

et al.,

1981), and a quicker alarm response is elicited when the sound signal intensity rises rapidly compared to sound rising more slowly to the same level.

Investigations of fish behavior in relation to vessel noise (Olsen

et al.,

1983; Ona, 1988; Ona and Godo, 1990) have shown that fish react when the sound from the engines and propeller exceeds a certain level. Avoidance reactions have been observed in fish such as cod and herring when vessels approached close enough that received sound levels are 110 dB to 130 dB (Nakken, 1992; Olsen, 1979; Ona and Godo, 1990; Ona and Toresen, 1988). However, other researchers have found that fish such as polar cod, herring, and capelin are often attracted to vessels (apparently by the noise) and swim toward the vessel (Rostad

et al.,

2006). Typical sound source levels of vessel noise in the audible range for fish are 150 dB to 170 dB (Richardson

et al.,

1995).

Carlson (1994), in a review of 40 years of studies concerning the use of underwater sound to deter salmonids from hazardous areas at hydroelectric dams and other facilities, concluded that salmonids were able to respond to low-frequency sound and to react to sound sources within a few feet of the source. He speculated that the reason that underwater sound had no effect on salmonids at distances greater than a few feet is because they react to water particle motion/acceleration, not sound pressures. Detectable particle motion is produced within very short distances of a sound source, although sound pressure waves travel farther.

Potential Impacts to the Benthic Environment

Apache's seismic survey requires the deployment of a submersible recording system in the inter-tidal and marine zones. An autonomous “nodal” (

i.e.,

no cables) system would be placed on the seafloor by specific vessels in lines parallel to each other with a node line spacing of 402 m (0.25 mi). Each nodal “patch” would have six to eight node lines parallel to each other. The lines generally run perpendicular to the shoreline. An entire patch would be placed on the seafloor prior to airgun activity. As the patches are surveyed, the node lines would be moved either side to side or inline to the next location. Placement and retrieval of the nodes may cause temporary and localized increases in turbidity on the seafloor. The substrate of Cook Inlet consists of glacial silt, clay, cobbles, pebbles, and sand (Sharma and Burrell, 1970). Sediments like sand and cobble dissipate quickly when suspended, but finer materials like clay and silt can create thicker plumes that may harm fish; however, the turbidity created by placing and removing nodes on the seafloor would settle to background levels within minutes after the cessation of activity. In addition, seismic noise will radiate throughout the water column from airguns and pingers until it dissipates to background levels.

Habitat Impacts—Conclusion

No studies have demonstrated that seismic noise affects the life stages, condition, or amount of food resources (fish, invertebrates, eggs) used by marine mammals, except when exposed to sound levels within a few meters of the seismic source or in a few very isolated cases. Where fish or invertebrates did respond to seismic noise, the effects were temporary and of short duration. The effects are also largely behavioral, rather than physiological. Consequently, disturbance to fish species due to the activities associated with the seismic survey (

i.e.,

placement and retrieval of nodes and noise from sound sources) would be short term and fish would be expected to return to their pre-disturbance behavior once seismic survey activities cease.

Based on the preceding discussion, the activity is not expected to have any habitat-related effects that could cause significant or long-term consequences for individual marine mammals or their populations. Behavioral effects may be exhibited by fish species but as discussed above, these are also expected to be short term behavioral effects.

Mitigation

In order to issue an incidental take authorization (ITA) under section 101(a)(5)(A) of the MMPA, NMFS must set forth the permissible methods of taking pursuant to such activity, and other means of effecting the least practicable impact on such species or stock and its habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stock for taking for certain subsistence uses (where relevant).

Mitigation Measures in Apache's Application

For the mitigation measures, Apache listed the following protocols to be implemented during its seismic survey program in Cook Inlet, which were incorporated into NMFS' proposed rule.

1. Operation of Mitigation Airgun at Night

Apache will conduct both daytime and nighttime operations. Nighttime operations would be initiated only if a “mitigation airgun” (typically the 10 in

3

) has been continuously operational from the time that PSO monitoring has ceased for the day. Seismic activity would not ramp up from an extended shut-down (

i.e.,

when the airgun has been down with no activity for at least 10 minutes) during nighttime operations, and survey activities would be suspended until the following day. At night, the vessel captain and crew would maintain lookout for marine mammals and would order the airgun(s) to be shut down if marine mammals are observed in or about to enter the established exclusion zones.

2. Exclusion and Disturbance Zones

Apache will establish exclusion zones to avoid Level A harassment (“injury exclusion zone”) of all marine mammals and to minimize Level B harassment (“disturbance exclusion zone”) for any number of belugas and for groups of five or more killer whales or harbor porpoises detected within the designated zones. The injury exclusion zone will correspond to the area around the source within which received levels equal or exceed 180 dB re 1 µPa [rms] for cetaceans and 190 dB re 1 µPa [rms] for pinnipeds and Apache will shut down or power down operations if any marine mammals are seen approaching or entering this zone (more detail below). The disturbance exclusion zone will correspond to the area around the source within which received levels equal or exceed 160 dB re 1 µPa [rms] and Apache will implement power down and/or shutdown measures, as appropriate, if any beluga whales or group of five or more killer whales or harbor porpoises are seen entering or approaching the disturbance exclusion zone.

3. Power Down and Shutdown Procedures

A power down is the immediate reduction in the number of operating energy sources from a full array firing to a mitigation airgun. A shutdown 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 shutdown (

i.e.,

no sources firing). Following a power down or a shutdown, airgun activity will not resume until the marine mammal has clearly left the applicable injury or disturbance exclusion zone. The animal will be considered to have cleared the zone if it: (1) Is visually observed to have left the zone; (2) has not been seen within the zone for 15 minutes in the case of pinnipeds and small odontocetes; or (3) has not been seen within the zone for 30 minutes in the case of large odontocetes, including killer whales and belugas.

4. Ramp-Up Procedures

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 air guns 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 the time for them to leave the area and thus avoid any potential injury or impairment of their hearing abilities.

During the seismic survey, the seismic operator will ramp up the airgun array slowly. NMFS requires that the rate of ramp-up to be no more than 6 dB per 5-minute period. Ramp-up is used at the start of airgun operations, after a power- or shut-down, and after any period of greater than 10 minutes in duration without airgun operations (

i.e.,

extended shutdown).

A full ramp-up after a shutdown will not begin until there has been a minimum of 30 minutes of observation of the applicable exclusion zone by PSOs to assure that no marine mammals are present. The entire exclusion zone must be visible during the 30-minute lead-in to a full ramp up. If the entire exclusion zone is not visible, then ramp-up from a cold start cannot begin. If a marine mammal(s) is sighted within the injury exclusion zone during the 30-minute watch prior to ramp-up, ramp-up will be delayed until the marine mammal(s) is sighted outside of the zone or the animal(s) is not sighted for at least 15-30 minutes: 15 minutes for small odontocetes and pinnipeds (

e.g.

harbor porpoises, harbor seals, and Steller sea lions), or 30 minutes for large odontocetes (

e.g.,

killer whales and beluga whales).

5. Speed or Course Alteration

If a marine mammal is detected outside the Level A injury exclusion zone and, based on its position and the relative motion, is likely to enter that zone, the vessel's speed and/or direct course may, when practical and safe, be changed to also minimize the effect on the seismic program. This can be used in coordination with a power down procedure. The marine mammal activities and movements relative to the seismic and support vessels will be closely monitored to ensure that the marine mammal does not approach within the applicable exclusion radius. If the mammal appears likely to enter the exclusion radius, further mitigative actions will be taken,

i.e.,

either further

course alterations, power down, or shut down of the airgun(s).

6. Measures for Beluga Whales and Groups of Killer Whales and Harbor Porpoises

The following additional protective measures for beluga whales and groups of five or more killer whales and harbor porpoises are required. Specifically, a 160-dB vessel monitoring zone would be established and monitored in Cook Inlet during all seismic surveys. If a beluga whale or groups of five or more killer whales and/or harbor porpoises are visually sighted approaching or within the 160-dB disturbance zone, survey activity would not commence until the animals are no longer present within the 160-dB disturbance zone. Whenever beluga whales or groups of five or more killer whales and/or harbor porpoises are detected approaching or within the 160-dB disturbance zone, the airguns may be powered down before the animal is within the 160-dB disturbance zone, as an alternative to a complete shutdown. If a power down is not sufficient, the sound source(s) shall be shut-down until the animals are no longer present within the 160-dB zone.

Additional Mitigation Measures Required by NMFS

In addition to the mitigation measures proposed by Apache, NMFS requires implementation of the following mitigation measures.

Susitna Delta Exclusion Zone

Apache must not operate airguns within 10 miles (16 km) of the mean lower low water (MLLW) line of the Susitna Delta (Beluga River to the Little Susitna River) between April 15 and October 15. The purpose of this mitigation measure is to protect beluga whales in this portion of designated critical habitat that is particularly important for beluga whale feeding and calving between mid-April and mid-October. This is a change from the proposed rule, which proposed an exclusion from the mean higher high water line (MHHW). The range of the setback required by NMFS is intended to protect this important habitat area during high beluga use and also to create an effective buffer where sound does not encroach on this habitat. This seasonal exclusion will be in effect from April 15-October 15. Seismic exploration and associated activities may occur within this area from October 16-April 14.

Mitigation Airgun

The mitigation airgun will be operated at approximately one shot per minute, only during daylight and when there is good visibility, and will not be operated for longer than 3 hours in duration. In cases when the next start-up after the turn is expected to be during low light or low visibility, use of the mitigation airgun may be initiated 30 minutes before local sunset or low visibility conditions occur and may be operated until the start of the next seismic acquisition line but not longer than three hours continuously. The mitigation gun must still be operated at approximately one shot per minute.

Passive Acoustic Monitoring (PAM)

NMFS also requires that Apache use passive acoustic monitoring (PAM) during non-daylight hours for marine mammal detections as well as use PAM to confirm the lack of marine mammals in the potential ensonified area to ramp up airguns after a power down or shutdown in non-daylight hours, with the success and potential continuation of this method to be reviewed at the annual LOA stage. Following a power down or shutdown a trained PSO must use detection equipment and listen for 30 minutes. When 30 minutes have passed without detection of beluga, humpback whale, or Steller sea lion detection, the ramp-up can begin. NMFS will work with Apache before issuance of an LOA to design an appropriate system for this detection and will evaluate the effectiveness when considering subsequent LOAs.

Stranding Measures

NMFS requires that Apache suspend seismic operations if a live marine mammal stranding is reported in Cook Inlet coincident to, or within 72 hours of, seismic survey activities involving the use of airguns (regardless of any suspected cause of the stranding). The shutdown must occur if the stranding location is within a radius two times that of the 160 dB isopleth of the largest airgun array configuration in use. This distance was chosen to create an additional buffer beyond the distance at which animals would typically be considered harassed, as animals involved in a live stranding event are likely compromised, with potentially increased susceptibility to stressors, and the goal is to decrease the likelihood that they are further disturbed or impacted by the seismic survey, regardless of what the original cause of the stranding event was. Shutdown procedures will remain in effect until NMFS determines and advises Apache that all live animals involved in the stranding have left the area (either of their own volition or following herding by responders).

Measures for Unexpected Species

Finally, NMFS requires that if during the seismic activities any marine mammal species are encountered for which take is not authorized, and that are likely to be exposed to sound pressure levels (SPLs) greater than or equal to 160 dB re 1 µPa (rms), then Apache must alter speed or course or power down or shut-down the sound source to avoid take of those species.

Mitigation Conclusions

NMFS has carefully evaluated Apache's proposed mitigation measures and considered a range of other measures in the context of ensuring that NMFS prescribes the means of effecting the least practicable adverse 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 measures are 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 seismic airguns, 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 seismic airguns 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 seismic airguns or other activities expected to

result in the take of marine mammals (this goal may contribute to 1, 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 measures, as well as other measures considered by NMFS, NMFS has determined that the required mitigation measures provide the means of effecting the least practicable adverse impact on marine mammals species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.

Monitoring and Reporting

In order to issue an ITA for an activity, section 101(a)(5)(D) of the MMPA states that NMFS must set forth “requirements pertaining to the monitoring and reporting of such taking”. The MMPA implementing regulations at 50 CFR 216.104(a)(13) indicate that requests for 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. Apache submitted information regarding marine mammal monitoring to be conducted during seismic operations as part of the proposed rule application. That information can be found in Sections 12 and 14 of the application.

Monitoring measures proposed by the applicant or prescribed by NMFS should contribute to or accomplish one or more of the following top-level goals:

1. An increase in our understanding of the likely occurrence of marine mammal species in the vicinity of the action,

i.e.,

presence, abundance, distribution, and/or density of species.

2. An increase in our understanding of the nature, scope, or context of the likely exposure of marine mammal species to any of the potential stressor(s) associated with the action (

e.g.

sound or visual stimuli), through better understanding of one or more of the following: The action itself and its environment (

e.g.

sound source characterization, propagation, and ambient noise levels); the affected species (

e.g.

life history or dive pattern); the likely co-occurrence of marine mammal species with the action (in whole or part) associated with specific adverse effects; and/or the likely biological or behavioral context of exposure to the stressor for the marine mammal (

e.g.

age class of exposed animals or known pupping, calving or feeding areas).

3. An increase in our understanding of how individual marine mammals respond (behaviorally or physiologically) to the specific stressors associated with the action (in specific contexts, where possible,

e.g.,

at what distance or received level).

4. An increase in our understanding of how anticipated individual responses, to individual stressors or anticipated combinations of stressors, may impact either: The long-term fitness and survival of an individual; or the population, species, or stock (

e.g.,

through effects on annual rates of recruitment or survival).

5. An increase in our understanding of how the activity affects marine mammal habitat, such as through effects on prey sources or acoustic habitat (

e.g.,

through characterization of longer-term contributions of multiple sound sources to rising ambient noise levels and assessment of the potential chronic effects on marine mammals).

6. An increase in understanding of the impacts of the activity on marine mammals in combination with the impacts of other anthropogenic activities or natural factors occurring in the region.

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

8. An increase in the probability of detecting marine mammals (through improved technology or methodology), both specifically within the safety zone (thus allowing for more effective implementation of the mitigation) and in general, to better achieve the above goals.

Monitoring Results From Previously Authorized Activities

As noted earlier in this document, NMFS has issued three IHAs to Apache for this same type of activity. No seismic surveys were conducted under the IHA issued in February 2013 (became effective March 1, 2013). Apache conducted seismic operations under the first IHA issued in April 2012. Below is a summary of the results from the monitoring conducted in accordance with the 2012 and 2014 IHAs.

Marine mammal monitoring was conducted in central Cook Inlet between May 6 and September 30, 2012, which resulted in a total of 6,912 hours of observations. There was also monitoring from April 2, 2014, through June 27, 2014, which resulted in a total of 3,029 hours of observations. Monitoring was conducted from the two seismic survey vessels, a mitigation/monitoring vessel, four land platforms, and an aerial platform (either a helicopter or small fixed wing aircraft). PSOs monitored from the seismic vessels, mitigation/monitoring vessel, and land platforms during all daytime seismic operations. Aerial overflights were conducted 1-2 times daily over the survey area and surrounding coastline, including the major river mouths, to monitor for larger concentrations of marine mammals in and around the survey site. PAM took place from the mitigation/monitoring vessel during all nighttime seismic survey operations and most daytime seismic survey operations in 2012. During the entire 2012 survey season, Apache's PAM equipment yielded only six confirmed marine mammal detections, one of which was a Cook Inlet beluga whale.

Six identified species and three unidentified species of marine mammals were observed from the vessel, land, and aerial platforms between May 6 and September 30, 2012. Eight identified species and three unidentified species were observed in 2014. The species observed included Cook Inlet beluga whales, harbor seals, harbor porpoises, Dall's porpoises, humpback whale, minke whale, Steller sea lions, gray whales, and California sea lions. PSOs also observed unidentified species, including a large cetacean, pinniped, and marine mammal. There were a total of 882 sightings and an estimated 5,232 individuals (the number of individuals is typically higher than the number of sightings because a single sighting may consist of multiple individuals) in 2012. There were a total of 645 sightings and an estimated 922 individuals in 2014. Harbor seals were the most frequently observed marine mammal at 563 sightings of approximately 3,471 individuals in 2012 and 492 sightings of approximately 613 individuals in 2014. In 2012 there were 151 sightings of approximately 1,463 individual belugas, and 57 sightings of approximately 170 individual belugas in 2014. In 2012, there were 137 sightings of approximately 190 individual harbor porpoises, with 77 sightings of approximately 113 individuals in 2014.

There were nine grey whales seen in 2012 but only one seen in 2014. Steller sea lions were observed on three separate occasions in 2012 (4 individuals), while seen only twice (2 individuals) in 2014. No killer whales were observed during seismic survey operations conducted under the 2012 or 2014 IHA. Mitigation measures were implemented for species not included in the IHA to prevent unauthorized takes. In 2012 there were 17 recorded instances of Level B take, which consisted of four harbor porpoises and 13 harbor seals. In 2014, only 29 exposures to the 160dB isopleth were reported: 12 beluga whales, 6 harbor porpoise, 9 harbor seals, and 2 humpback whales. Across both years of activity, behavioral reactions included swimming and traveling, as well as bottlenosing (for harbor porpoises) and diving, sin

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