Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to BlueCrest Alaska Operating, LLC Drilling Activities at Cosmopolitan State Unit, Alaska, 2016
Federal Register, Volume 81 Issue 106 (Thursday, June 2, 2016)
Federal Register Volume 81, Number 106 (Thursday, June 2, 2016)
From the Federal Register Online via the Government Publishing Office www.gpo.gov
FR Doc No: 2016-12886
June 2, 2016
Department of Commerce
National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to BlueCrest Alaska Operating, LLC Drilling Activities at Cosmopolitan State Unit, Alaska, 2016; Notice
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to BlueCrest Alaska Operating, LLC Drilling Activities at Cosmopolitan State Unit, Alaska, 2016
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request for comments.
SUMMARY: NMFS has received an application from BlueCrest Alaska Operating, LLC (BlueCrest) for an Incidental Harassment Authorization (IHA) to take marine mammals, by harassment, incidental to conducting an oil and gas production drilling program in lower Cook Inlet, AK, on State of Alaska Oil and Gas Lease 384403 under the program name of Cosmopolitan State during the 2016 open water season. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an IHA to BlueCrest to incidentally take, by Level B harassment only, marine mammals during the specified activity.
DATES: Comments and information must be received no later than July 5, 2016.
ADDRESSES: Comments on the application should be addressed to Jolie Harrison, Chief, Permits and Conservation Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910. The mailbox address for providing email comments is ITP.Youngkin@noaa.gov. NMFS is not responsible for email comments sent to addresses other than the one provided here. Comments sent via email, including all attachments, must not exceed a 25-
megabyte file size.
Instructions: All comments received are a part of the public record and will generally be posted to http://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information (e.g., name, address) voluntarily submitted by the commenter may be publicly accessible. Do not submit Confidential Business Information or otherwise sensitive or protected information.
An electronic copy of the application, NMFS' Draft Programmatic Environmental Assessment (EA) for activities in Cook Inlet, and a list of the references used in this document may be obtained by visiting the Internet at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. In case of problems accessing these documents, please call the contact listed below. Documents cited in this notice may also be viewed, by appointment, during regular business hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Dale Youngkin, Office of Protected Resources, NMFS, (301) 427-8401.
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; other means of effecting the least practicable impact on the species or stock and its habitat; and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . . an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.''
Except with respect to certain activities not pertinent here, the MMPA defines ``harassment'' as: ``any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild Level A harassment; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering Level B harassment.''
Summary of Request
On September 28, 2015 NMFS received an IHA application from BlueCrest for the taking of marine mammals incidental to an oil and gas production drilling program in lower Cook Inlet, AK, during the 2016 open water season. Typically, the open water (i.e., ice-free) season is mid-April through October; however, BlueCrest would only operate during a portion of this season, from August 1, 2016 through October 31, 2016. NMFS determined that the application was adequate and complete on April 12, 2016.
BlueCrest proposes to conduct and oil and gas production drilling program using the Spartan 151 drill rig (or similar rig) in lower Cook Inlet. This work would include drilling up to three wells with a total operating time of approximately 91 days during the 2016 open-water season, (August 1 through October 31). In 2013, BlueCrest, then in partnership with Buccaneer Energy, conducted exploratory oil and gas drilling at the Cosmopolitan State #A-1 well site (then called Cosmopolitan State #1). Beginning in 2016, BlueCrest intends to drill two more wells (Cosmopolitan State #A-2 and #A-3). These directionally drilled wells have top holes located a few meters from the original Cosmopolitan State #A-1, and together would feed to a future single offshore platform. Both #A-2 and #A-3 may involve test drilling into oil layers. After testing, the oil horizons will be plugged and abandoned, while the gas zones will be suspended pending platform construction. A third well (#B-1) will be located approximately 1.7 kilometers (km; 1 mile mi) southeast of the other wells. This well will be drilled into oil formations to collect geological information. After testing, the oil horizon will be plugged and abandoned, while the gas zones will be suspended pending platform construction. All four wells (one existing and up to three new) would be located within Lease 384403. Specific locations (latitude and longitude and depth) of each well is provided in Table 1-1 and depicted in Figure 1-1 of BlueCrest's application.
The following specific aspects of the proposed activities are likely to result in the take of marine mammals: (1) Impact hammering of the drive pipe at the well prior to drilling, and (2) vertical seismic profiling (VSP). Underwater noise associated with drilling and rig operation associated with the specified activity has been determined to have little effect on marine mammals (based on Marine Acoustics, Inc.'s 2011 acoustical testing of the Spartan 151 while drilling). Take, by Level B harassment only, of nine marine mammal species is anticipated to result from the specified activity.
Description of the Specified Activity
BlueCrest proposes to conduct oil and gas production drilling operations at up to three sites in lower Cook Inlet during the 2016 open water (ice-free) season (August 1 through October 31), using the Spartan 151 jack-up drill rig, depending on availability. The activities of relevance to this IHA request include: Impact hammering of the drive pipe and VSP seismic operations. BlueCrest proposes to mobilize and demobilize the drill rig to and from the well locations, and will utilize both helicopters and vessels to conduct resupply, crew change, and other logistics during the drilling program. These mobilization/demobilization activities, and actual drilling/operation of the rig, are also part of the proposed activity but are not considered activities of relevance to this IHA because take is not being authorized for those activities. More information regarding these activities and why they are/are not considered activities of relevance to this IHA can be found in the Detailed Description of Activities section below.
Dates and Duration
The 2016 drilling program (which is the subject of this IHA request) would occur during the 2016 open water season (August 1 through October 31). BlueCrest estimates that the drilling period could take up to 91 days in the above time period. The exact start date is currently unknown, and dependent on the scheduling availability of the proposed drill rig. It is expected that each well will take approximately 30 days to complete, including well testing time.
During this time period, drive pipe hammering would only occur for a period of 1 to 3 days at each well site (although actual sound generation would occur only intermittently during this time period), and VSP seismic operations would only occur for a period of less than 1 to 2 days at each well site. This IHA (if issued) would be effective for 1 year, beginning on August 1, 2016.
Specified Geographic Region
BlueCrest's proposed program would occur at Cosmopolitan State #B-1 (originally Cosmopolitan #2), Cosmopolitan State #A-1 (originally Cosmopolitan State #1), #A-2, and #A-3 in lower Cook Inlet, AK. The exact location of BlueCrest's well sites can be seen in Figure 1-1 in BlueCrest's IHA application and location information (latitude/
longitude and water depth) is provided in Table 1-1 in the IHA application.
Detailed Description of Activities
Drill Rig Mobilization and Towing
BlueCrest proposes to conduct its production and exploratory drilling using the Spartan 151 drill rig or similar rig (see Figure 1-2 of the IHA application). The Spartan 151 is a 150 H class independent leg, cantilevered jack-up drill rig, with a drilling capability of 25,000 ft but can operate in maximum water depths up to only 150 ft. The rig will be towed by ocean-going tugs licensed to operate in Cook Inlet. While under tow, the rig operations will be monitored by BlueCrest and the drilling contractor management, both aboard the rig and onshore.
The Spartan 151 is currently moored at the Seward Marine Industrial Center, directly across Resurrection Bay from the City of Seward. The intention is to move the drill rig to the Cosmopolitan Site #B-1 well site in July, a distance of approximately 314 km (195 miles mi). It is anticipated that this tow would be accomplished within three days. Any move post-project will be controlled by the owner of the drilling rig. The rig will be towed between locations by ocean-going tugs that are licensed to operate in Cook Inlet. Move plans will receive close scrutiny from the rig owner's tow master as well as the owner's insurers, and will be conducted in accordance with state and federal regulations. Rig moves will be conducted in a manner to minimize any potential risk regarding safety as well as cultural or environmental impact.
The rig will be wet-towed by two or three ocean-going tugs licensed to operate in Cook Inlet. Ship strike of marine mammals during tow is not an issue of major concern. Most strikes of marine mammals occur when vessels are traveling at speeds between 24 and 44 km/hr (13 and 24 knots kt) (http://www.nmfs.noaa.gov/pr/pdfs/shipstrike/ss_speed.pdf), well above the 1.9- to 7.4-km/hr (1- to 4-kt) drill rig tow speed expected. However, noise from towing was considered as a potential impact. Tugs generate their loudest sounds while towing due to propeller cavitation. While these continuous sounds have been measured at up to 171 dB re 1 muPa-m (rms) at 1-meter source (broadband), they are generally emitted at dominant frequencies of less than 5 kHz (Miles et al., 1987; Richardson et al., 1995a, Simmonds et al., 2004). For the most part, the dominant noise frequencies from propeller cavitation are significantly lower than the dominant hearing frequencies for pinnipeds and toothed whales, including beluga whales (Wartzok and Ketten, 1999), so towing activities are not considered an activity that would `take' marine mammals.
Drive Pipe Hammering
A drive pipe is a relatively short, large-diameter pipe driven into the sediment prior to the drilling of oil wells. This section of tubing serves to support the initial sedimentary part of the well, preventing the looser surface layer from collapsing and obstructing the wellbore. Drive pipes are usually installed using pile driving techniques. The term `drive pipe' is often synonymous to the term `conductor pipe'; however, a 50.8-centimeter (cm; 20-inch in) conductor pipe will be drilled (not hammered) inside the drive pipe, and will be used to transport (conduct) drillhead cuttings to the surface. Therefore, there is no noise concern associated with the conductor pipe drilling, and the potential for acoustical harassment of marine mammals is due to the hammering of the drive pipe. BlueCrest proposes to drive approximately 200 ft (60 m) below mudline of 30-inch drive pipe at each of the well sites prior to drilling using a Delmar D62-22 impact hammer. This hammer has impact weight of 13,640 pounds (6,200 kg) and reaches maximum impact energy of 165,215 foot-pounds (224 kilonewton-meters) at a drop height of 12 ft (3.6 m).
Blackwell (2005) measured the noise produced by a Delmar D62-22 driving 36-inch steel pipe in upper Cook Inlet and found sound pressure levels (SPLs) to exceed 190 dB re 1muPa-m (rms) at about 200 ft (60 m), 180 dB re 1muPa-m (rms) at about 820 ft (250 m), and 160 dB re 1muPa-m (rms) at just less than 1.2 mi (1.9 km). Illingworth and Rodkin (2014) measured the hammer noise operating from another rig, the Endeavour, in 2013 and found SPLs to exceed 190 dB re 1muPa-m (rms) at about 180 ft (55 m), 180 dB re 1muPa-m (rms) at about 560 ft (170 m), and 160 dB re 1muPa-m (rms) at 1 mi (1.6 km). The drive pipe driving event is expected to last 1 to 3 days at each well site, although actual sound generation (pounding) would occur only intermittently during this period.
Drilling and Standard Operation
The Spartan 151 was hydro-acoustically measured by Marine Acoustics, Inc. while operating in 2011. The survey results showed that continuous noise levels exceeding 120 dB re 1muPa (NMFS' current threshold for estimating Level B harassment from continuous underwater noise) extended
out only 164 ft (50 m), and that this sound was largely associated with the diesel engines used as hotel power generators.
Deep well pumps were not identified as a sound source by Marine Acoustics, Inc. (2011) during their acoustical testing of the Spartan 151, and are not considered an activity that would `take' marine mammals.
Vertical Seismic Profiling
Once a well is drilled, accurate follow-up seismic data can be collected by placing a receiver at known depths in the borehole and shooting a seismic airgun at the surface near the borehole. These gathered data not only provide high resolution images of the geological layers penetrated by the borehole but can be used to accurately correlate (or correct) the original surface seismic data. The procedure is known as vertical seismic profiling (VSP).
BlueCrest intends to conduct VSP operations at the end of drilling each well using an array of airguns with total volumes of between 600 and 880 cubic inches (in\3\). The VSP operation is expected to last less than 1 or 2 days at each well site. Assuming a 1-meter source level of 227 dB re 1muPa (based on manufacturer's specifications) for an 880 in\3\ array and using Collins et al.'s (2007) transmission loss model for Cook Inlet (227 - 18.4 Log(R) - 0.00188), the 190 dB radius from the source was estimated at 330 ft (100 m), the 180 dB radius at 1,090 ft (332 m), and the 160 dB radius at 1.53 mi (2.46 km). 190 dB and 180 dB are the current NMFS thresholds for estimating Level A harassment from underwater noise exposure for pinnipeds and cetaceans, respectively, and 160 dB is the current NMFS threshold for estimating Level B harassment from exposure to underwater impulse noises. Therefore, VSP operations are considered an activity that has the potential to `take' marine mammals.
Illingworth and Rodkin (2014) measured the underwater sound levels associated with a July 2013 VSP operation using a 750 in\3\ array and found sound levels exceeding 160 dB re 1 muPa (rms) extended out 1.54 mi (2.47 km), virtually identical to the modeled distance. The measured radius to 190 dB was 394 ft (120 m) and to 180 dB was 787 ft (240 m).
Helicopter and Supply Vessel Support
Helicopter logistics for project operations will include transportation for personnel, groceries, and supplies. Helicopter support will consist of a twin turbine Bell 212 (or equivalent) helicopter certified for instrument flight rules land and over water operations. Helicopter crews and support personnel will be housed in existing Kenai area facilities. The helicopter will be based at the Kenai Airport to support rig crew changes and cargo handling. Fueling will take place at these facilities. No helicopter refueling will take place on the rig.
Helicopter flights to and from the rig are expected to average two per day. Flight routes will follow a direct route to and from the rig location, and flight heights will be maintained 1,000 to 1,500 feet above ground level to avoid take of marine mammals (Richardson et al., 1995a). At these altitudes, there are not expected to be impacts from sound generation on marine mammals, and are not considered an activity that would `take' marine mammals. The aircraft will be dedicated to the drilling operation and will be available for service 24 hours per day. A replacement aircraft will be available when major maintenance items are scheduled.
Major supplies will be staged on-shore at the Kenai OSK Dock. Required supplies and equipment will be moved from the staging area by contracted supply vessels and loaded aboard the rig when the rig is established on a drilling location. Major supplies will include fuel, drilling water, mud materials, cement, casing, and well service equipment. Supply vessels also will be outfitted with fire-fighting systems as part of fire prevention and control as required by Cook Inlet Spill Prevention and Response, Inc. The specific supply vessels have not been identified; however, typical offshore drilling support work vessels are of steel construction with strengthened hulls to give the capability of working in extreme conditions. Additional information about logistics and fuel and waste management can be found in Section 1.2 of BlueCrest's IHA application.
Description of Marine Mammals in the Area of the Specified Activity
Several marine mammal species occur in lower Cook Inlet. The marine mammal species under NMFS's jurisdiction include: Beluga whale (Delphinapterus leucas); harbor porpoise (Phocoena phocoena); killer whale (Orcinus orca); gray whale (Eschrichtius robustus); minke whale (Balaenoptera acutorostrata); Dall's porpoise (Phocoenoides dalli); humpback whale (Megaptera novaeangliae); harbor seal (Phoca vitulina richardsi); and Steller sea lion (Eumetopias jubatus).
Data collected during marine mammal monitoring at Cosmopolitan State #A-1 during summer 2013 recorded at least 154 harbor porpoise (152 within 1.2 mi (2 km) of operation, 12 of which were observed inside 853 ft (260 m) of the rig); 77 harbor seals (18 of these within 853 ft 260 m of the active drill rig); 42 minke whales (all except for three recorded over 984 ft (300 m) from the active drill rig; 19 Dall's porpoise (none in close proximity to the active drill rig); 12 gray whales (observed offshore of Cape Starichkof; none closely approached drilling operations); seven Steller sea lions (none in close proximity to the active drill rig); 18 killer whales (17 within 1.2 mi (2 km) of operations); and one beluga whale (observed at a distance well beyond 1.8 mi (3 km) between May and August 2013 (112 days of monitoring). Based on their seasonal patterns, gray whales could be encountered in low numbers during operations. Minke whales have been considered migratory in Alaska (Allen and Angliss, 2014) but have recently been observed off Cape Starichkof and Anchor Point, including in winter. The remaining species could be encountered year-round. Humpback whales are common in the very southern part of Cook Inlet and typically do not venture north of Kachemak Bay (B. Mahoney, NMFS, pers. comm., August 2014), which is south of the proposed Cosmopolitan drilling site. Therefore, while it is unlikely that humpback whales, gray whales, or minke whales would be encountered during the proposed project, it is still a possibility based on observations from past monitoring efforts, and therefore take of these species was requested.
Of these marine mammal species, Cook Inlet beluga whales, humpback whales, and the western distinct population segment (DPS) of Steller sea lions are listed as endangered under the Endangered Species Act (ESA). The eastern DPS of Steller sea lions was recently removed from the endangered species list (78 FR 66139, November 4, 2013) but currently retains its status as ``depleted'' under the MMPA along with the western DPS, Cook Inlet beluga whales, and humpback whales.
Despite these designations, Cook Inlet beluga whales and the western DPS of Steller sea lions have not made significant progress towards recovery. Data indicate that the Cook Inlet population of beluga whales decreased at a rate of 0.6 percent annually between 2002 and 2012 (Allen and Angliss, 2014). The NMFS 2014 Stock Assessment Report (SAR) estimated 312 Cook Inlet beluga whales, which is a three-
year average. However, the most
recent abundance estimate is 340 beluga whales (Shelden et al., 2015).
Regional variation in trends in Western DPS 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).
The Central North Pacific humpback whale stock, consisting of winter/spring populations of the Hawaiian Islands which migrate primarily to northern British Columbia/Southeast Alaska, the Gulf of Alaska, and the Bering Sea/Aleutian Islands (Baker et al., 1990; Perry et al., 1990; Calambokidis et al., 1997), has increased over the past two decades. Different studies and sampling techniques in Hawaii and Alaska have indicated growth rates ranging from 4.9-10 percent per year in the 1980s, 1990s, and early 2000s (Mobley et al., 2001; Mizroch et al., 2004; Zerbini et al., 2006; Calambokidis et al., 2008). It is also clear that the abundance has increased in Southeast Alaska, though a trend for the Southeast Alaska portion of this stock cannot be estimated from the data because of differences in methods and areas covered (Allen and Angliss, 2013). On April 21, 2015, NMFS published a notice in the Federal Register requesting comments on a proposal to revise the listing status of humpback whales by delineating the species into 14 DPS, changing the Central North Pacific stock of humpback whales to become the Hawaii DPS. NMFS also proposed to delist the Hawaii DPS (80 FR 22304).
Pursuant to the ESA, critical habitat has been designated for Cook Inlet beluga whales and Steller sea lions. The proposed drilling program does not fall within critical habitat designated in Cook Inlet for beluga whales or within critical habitat designated for Steller sea lions. The Cosmopolitan State unit is nearly 100 miles south of beluga whale Critical Habitat Area 1 and approximately 27 miles south of Critical Habitat Area 2. It is also located about 25 miles north of the isolated patch of Critical Habitat Area 2 found in Kachemak Bay. Area 2 is based on dispersed fall and winter feeding and transit areas in waters where whales typically appear in smaller densities or deeper waters (76 FR 20180, April 11, 2011). No critical habitat has been designated for humpback whales.
BlueCrest is requesting take of belugas, humpback whales and Steller sea lions, which have been observed in close proximity to the Cosmopolitan site (G. Green, Owl Ridge, personal communication). In addition, BlueCrest is requesting take of gray, minke, and killer whales, harbor and Dall's porpoise, and harbor seals. See Table 1 below for more information on the habitat, range, population, and status of these species.
Table 1--The Habitat, Abundance, and Conservation Status of Marine Mammals
Species Habitat Range Estimate ESA \2\ MMPA \3\
Humpback whale (Megaptera Coastal and Worldwide in all 10,103--Central EN D, S.
novaeangliae). inland waters. ocean basins. N. Pacific Stock.
Minke Whale (Balaenoptera Coastal and Bering and 1,233 \2\--Alaska NL NC.
acutorostra). inland waters. Chukchi Seas stock.
south to near
Gray Whale (Eschrichtius Coastal and North Pacific 20,990 \3\--E. NL NC.
robustus). inland waters. from Alaska to North Pacific
Beluga Whale (Delphinapterus Offshore waters Ice-covered 340--Cook Inlet EN D, S.
leucas). in winter; arctic and stock.
coastal/ subartic waters
estuarine waters of the Northern
in spring. Hemisphere.
Killer Whale (Orcinus orca).... Offshore to Throughout North 2,347--Alaska NL NC.
inland waterways. Pacific; along resident stock/
west coast of 587 Alaska
North America; transient stock.
Harbor Porpoise (Phocoena Coastal.......... Point Barrow, 31,046--Gulf of NL S.
phocoena). Alaska to Point Alaska stock.
Dall's Porpoise (Phocoenoides Over continental Throughout North 83,400--Alaska NL NC.
dalli). shelf adjacent Pacific. stock.
to slope and
Pacific harbor seal (Phoca Coastal and Coastal temperate 22,900--Cook NL NC.
vitulina richardii). Estuarine. to polar regions Inlet/Shelikof
in Northern stock.
Steller Sea Lion (Eumetopias Coastal.......... Northern Pacific 55,422--W. U.S. NL D, S.
jubatus). Rim from stock.
NA = Not available or not assessed.
\1\ Allen and Angliss (2015).
\2\ Zerbini et al. (2006).
\3\ Caretta et al. (2015).
\4\ U.S. Endangered Species Act: EN = Endangered, T = Threatened, DL = Delisted, and NL = Not listed.
\5\ U.S. Marine Mammal Protection Act: D = Depleted, S = Strategic, and NC = Not classified.
Beluga Whale (Delphinapterus leucas)
The Cook Inlet beluga whale DPS is a small geographically isolated population that is separated from other beluga populations by the Alaska Peninsula. The population is genetically (mtDNA) distinct from other Alaska populations suggesting the Peninsula is an effective barrier to genetic exchange (O'Corry-Crowe et al. 1997) and that these whales may have been separated from other stocks at least since the last ice age. Laidre et al. (2000) examined data from more than 20 marine mammal surveys conducted in the northern Gulf of Alaska and found that sightings of belugas outside Cook Inlet were exceedingly rare, and these were composed of a few stragglers from the Cook Inlet DPS observed at Kodiak Island, Prince William Sound, and Yakutat Bay. Several marine mammal surveys specific to Cook Inlet (Laidre et al. 2000, Speckman and Piatt 2000), including those that concentrated on beluga whales (Rugh et al. 2000, 2005a), clearly indicate that this stock largely confines itself to Cook Inlet. There is no indication that these whales make forays into the Bering Sea where they might intermix with other Alaskan stocks.
The Cook Inlet beluga DPS was originally estimated at 1,300 whales in 1979 (Calkins 1989) and has been the focus of management concerns since experiencing a dramatic decline in the 1990s. Between 1994 and 1998 the stock declined 47 percent which was attributed to overharvesting by subsistence hunting. Subsistence hunting was estimated to annually remove 10 to 15 percent of the population during this period. Only five belugas have been harvested since 1999, yet the population has continued to decline, with the most recent estimate at only 312 animals (Allen and Angliss 2014). NMFS listed the population as ``depleted'' in 2000 as a consequence of the decline, and as ``endangered'' under the Endangered Species Act (ESA) in 2008 when the population failed to recover following a moratorium on subsistence harvest. In April 2011, NMFS designated critical habitat for the beluga under the ESA (Figure 1).
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Prior to the decline, this DPS was believed to range throughout Cook Inlet and occasionally into Prince William Sound and Yakutat (Nemeth et al. 2007). However the range has contracted coincident with the population reduction (Speckman and Piatt 2000). During the summer and fall beluga whales are concentrated near the Susitna River mouth, Knik Arm, Turnagain Arm, and Chickaloon Bay (Nemeth et al. 2007) where they feed on migrating eulachon (Thaleichthys pacifiligcus) and salmon (Onchorhyncus spp.) (Moore et al. 2000). Critical Habitat Area
1 reflects this summer distribution (Figure 1). During the winter, beluga whales concentrate in deeper waters in the mid-inlet to Kalgin Island, and in the shallow waters along the west shore of Cook Inlet to Kamishak Bay (Critical Habitat Area 2; Figure 1). Some whales may also winter in and near Kachemak Bay.
The Cosmopolitan State lease does not fall within beluga whale critical habitat. Based on Goetz et al. (2012) beluga whale densities, both along the route from Port Graham and at the well site, are very low ( Low frequency cetaceans (13 species of mysticetes): functional hearing is estimated to occur between approximately 7 Hz and 25 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 48 kHz.
As mentioned previously in this document, nine marine mammal species (seven cetacean and two pinniped species) may occur in the drilling area of BlueCrest's lower Cook Inlet project. Of the seven cetacean species likely to occur in the proposed project area and for which take is requested, three are classified as low-frequency cetaceans (i.e., humpback, minke, and gray whales), two are classified as a mid-frequency cetacean (i.e., beluga and killer whales), and two are classified as high-frequency cetaceans (i.e., harbor and Dall's porpoises) (Southall et al., 2007). A species' functional hearing group is a consideration when we analyze the effects of exposure to sound on marine mammals.
Numerous studies have shown that underwater sounds from industry activities are often readily detectable by marine mammals in the water at distances of many kilometers. Numerous studies have also shown that marine mammals at distances more than a few kilometers away often show no apparent response to industry activities of various types (Miller et al., 2005; Bain and Williams, 2006). This is often true even in cases when the sounds must be readily audible to the animals based on measured received levels and the hearing sensitivity of that mammal group. Although various baleen whales, toothed whales, and (less frequently) pinnipeds have been shown to react behaviorally to underwater sound such as airgun pulses or vessels under some conditions, at other times mammals of all three types have shown no overt reactions (e.g., Malme et al., 1986; Richardson et al., 1995a; Madsen and Mohl, 2000; Croll et al., 2001; Jacobs and Terhune, 2002; Madsen et al., 2002; Miller et al., 2005). 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). The airgun arrays used in the Weir (2008) study were much larger than the array proposed for use during the limited VSP (total discharge volumes of 600 to 880 in\3\ for 1 to 2 days). In general, pinnipeds and small odontocetes seem to be more tolerant of exposure to some types of underwater sound than are baleen whales. Richardson et al. (1995a) found that vessel noise does not seem to strongly affect pinnipeds that are already in the water. Richardson et al. (1995a) went on to explain that seals on haul-outs sometimes respond strongly to the presence of vessels and at other times appear to show considerable tolerance of vessels.
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 as, auditory signals an animal is trying to receive. Masking is a phenomenon that affects animals that are 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 in situations where the temporal and spatial scope of the masking activities is extensive.
Masking occurs when anthropogenic sounds and signals (that the animal utilizes) overlap at both spectral and temporal scales. The sounds generated by the proposed equipment for the drilling program will consist of low frequency sources (most under 500 Hz). Lower frequency man-made sounds are more likely to affect detection of communication calls of low-frequency specialists and other potentially important natural sounds such as surf and prey noise. There is less concern regarding masking of conspecific vocalizations near the jack-up rig during drilling operations, as the species most likely to be found in the vicinity are mid- to high-frequency cetaceans or pinnipeds and not low-frequency cetaceans. Additionally, masking is not expected to be a concern from airgun usage due to the brief duration of use (less than a day to up to 2 days) and the low-frequency sounds that are produced by the airguns. 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), although the intensity of the sound is greatly reduced.
The ``stretching'' of sound described above 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, only low numbers of baleen whales are expected to occur within the proposed action area. Marine mammals are thought to sometimes 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 are 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 el 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., 1995a). 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.
Behavioral responses to sound are highly variable and context-
specific. Many different variables can influence an animal's perception of and response to (in both nature and magnitude) an acoustic event. An animal's prior
experience with a sound or sound source affects whether it is less likely (habituation) or more likely (sensitization) to respond to certain sounds in the future (animals can also be innately pre-disposed to respond to certain sounds in certain ways; Southall et al., 2007). Related to the sound itself, the perceived nearness of the sound, bearing of the sound (approaching vs. retreating), similarity of a sound to biologically relevant sounds in the animal's environment (i.e., calls of predators, prey, or conspecifics), and familiarity of the sound may affect the way an animal responds to the sound (Southall et al., 2007). Individuals (of different age, gender, reproductive status, etc.) among most populations will have variable hearing capabilities and differing behavioral sensitivities to sounds that will be affected by prior conditioning, experience, and current activities of those individuals. Often, specific acoustic features of the sound and contextual variables (i.e., proximity, duration, or recurrence of the sound or the current behavior that the marine mammal is engaged in or its prior experience), as well as entirely separate factors such as the physical presence of a nearby vessel, may be more relevant to the animal's response than the received level alone.
Exposure of marine mammals to sound sources can result in (but is not limited to) no response or any of the following observable responses: Increased alertness; orientation or attraction to a sound source; vocal modifications; cessation of feeding; cessation of social interaction; alteration of movement or diving behavior; avoidance; habitat abandonment (temporary or permanent); and, in severe cases, panic, flight, stampede, or stranding, potentially resulting in death (Southall et al., 2007). The biological significance of many of these behavioral disturbances is difficult to predict.
The following sub-sections provide examples of the variability in behavioral responses that could be expected given the different sensitivities of marine mammal species to sound.
Baleen Whales--Richardson et al. (1995b) reported changes in surfacing and respiration behavior and the occurrence of turns during surfacing in bowhead whales exposed to playback of underwater sound from drilling activities. These behavioral effects were localized and occurred at distances up to 1.2-2.5 mi (2-4 km).
Richardson et al. (2008) reported a slight change in the distribution of bowhead whale calls in response to operational sounds on BP's Northstar Island. The southern edge of the call distribution ranged from 0.47 to 1.46 mi (0.76 to 2.35 km) farther offshore, apparently in response to industrial sound levels. However, this result was only achieved after intensive statistical analyses, and it is not clear that this represented a biologically significant effect.
Richardson et al. (1995a) and Moore and Clarke (2002) reviewed a few studies that observed responses of gray whales to aircraft. Cow-
calf pairs were quite sensitive to a turboprop survey flown at 1,000 ft (305 m) altitude on the Alaskan summering grounds. In that survey, adults were seen swimming over the calf, or the calf swam under the adult (Ljungblad et al., 1983, cited in Richardson et al., 1995a and Moore and Clarke, 2002). However, when the same aircraft circled for more than 10 minutes at 1,050 ft (320 m) altitude over a group of mating gray whales, no reactions were observed (Ljungblad et al., 1987, cited in Moore and Clarke, 2002). Malme et al. (1984, cited in Richardson et al., 1995a and Moore and Clarke, 2002) conducted playback experiments on migrating gray whales. They exposed the animals to underwater noise recorded from a Bell 212 helicopter (estimated altitude = 328 ft 100 m), at an average of three simulated passes per minute. The authors observed that whales changed their swimming course and sometimes slowed down in response to the playback sound but proceeded to migrate past the transducer. Migrating gray whales did not react overtly to a Bell 212 helicopter at greater than 1,394 ft (425 m) altitude, occasionally reacted when the helicopter was at 1,000-1,198 ft (305-365 m), and usually reacted when it was below 825 ft (250 m; Southwest Research Associates, 1988, cited in Richardson et al., 1995a and Moore and Clarke, 2002). Reactions noted in that study included abrupt turns or dives or both. Green et al. (1992, cited in Richardson et al., 1995a) observed that migrating gray whales rarely exhibited noticeable reactions to a straight-line overflight by a Twin Otter at 197 ft (60 m) altitude. Overflights are likely to have little or no disturbance effects on baleen whales. Any disturbance that may occur would likely be temporary and localized.
Southall et al. (2007, Appendix C) reviewed a number of papers describing the responses of marine mammals to non-pulsed sound, such as that produced during drilling operations. In general, little or no response was observed in animals exposed at received levels from 90-120 dB re 1 microPa (rms). Probability of avoidance and other behavioral effects increased when received levels were from 120-160 dB re 1 microPa (rms). Some of the relevant reviews contained in Southall et al. (2007) are summarized next.
Baker et al. (1982) reported some avoidance by humpback whales to vessel noise when received levels were 110-120 dB (rms) and clear avoidance at 120-140 dB (sound measurements were not provided by Baker but were based on measurements of identical vessels by Miles and Malme, 1983).
Malme et al. (1983, 1984) used playbacks of sounds from helicopter overflight and drilling rigs and platforms to study behavioral effects on migrating gray whales. Received levels exceeding 120 dB induced avoidance reactions. Malme et al. (1984) calculated 10%, 50%, and 90% probabilities of gray whale avoidance reactions at received levels of 110, 120, and 130 dB, respectively. Malme et al. (1986) observed the behavior of feeding gray whales during four experimental playbacks of drilling sounds (50 to 315 Hz; 21-min overall duration and 10% duty cycle; source levels of 156-162 dB). In two cases for received levels of 100-110 dB, no behavioral reaction was observed. However, avoidance behavior was observed in two cases where received levels were 110-120 dB.
Richardson et al. (1990) performed 12 playback experiments in which bowhead whales in the Alaskan Arctic were exposed to drilling sounds. Whales generally did not respond to exposures in the 100 to 130 dB range, although there was some indication of minor behavioral changes in several instances.
McCauley et al. (1996) reported several cases of humpback whales responding to vessels in Hervey Bay, Australia. Results indicated clear avoidance at received levels between 118 to 124 dB in three cases for which response and received levels were observed/measured.
Palka and Hammond (2001) analyzed line transect census data in which the orientation and distance off transect line were reported for large numbers of minke whales. The authors developed a method to account for effects of animal movement in response to sighting platforms. Minor changes in locomotion speed, direction, and/or diving profile were reported at ranges from 1,847 to 2,352 ft (563 to 717 m) at received levels of 110 to 120 dB.
Biassoni et al. (2000) and Miller et al. (2000) reported behavioral observations for humpback whales exposed to a low-frequency sonar stimulus (160- to 330-Hz frequency band; 42-s tonal signal repeated every 6 min; source levels 170 to 200 dB) during playback experiments. Exposure to measured received levels
ranging from 120 to 150 dB resulted in variability in humpback singing behavior. Croll et al. (2001) investigated responses of foraging fin and blue whales to the same low frequency active sonar stimulus off southern California. Playbacks and control intervals with no transmission were used to investigate behavior and distribution on time scales of several weeks and spatial scales of tens of kilometers. The general conclusion was that whales remained feeding within a region for which 12 to 30 percent of exposures exceeded 140 dB.
Frankel and Clark (1998) conducted playback experiments with wintering humpback whales using a single speaker producing a low-
frequency ``M-sequence'' (sine wave with multiple-phase reversals) signal in the 60 to 90 Hz band with output of 172 dB at 1 m. For 11 playbacks, exposures were between 120 and 130 dB re 1 microPa (rms) and included sufficient information regarding individual responses. During eight of the trials, there were no measurable differences in tracks or bearings relative to control conditions, whereas on three occasions, whales either moved slightly away from (n = 1) or towards (n = 2) the playback speaker during exposure. The presence of the source vessel itself had a greater effect than did the M-sequence playback.
Finally, Nowacek et al. (2004) used controlled exposures to demonstrate behavioral reactions of northern right whales to various non-pulse sounds. Playback stimuli included ship noise, social sounds of conspecifics, and a complex, 18-min ``alert'' sound consisting of repetitions of three different artificial signals. Ten whales were tagged with calibrated instruments that measured received sound characteristics and concurrent animal movements in three dimensions. Five out of six exposed whales reacted strongly to alert signals at measured received levels between 130 and 150 dB (i.e., ceased foraging and swam rapidly to the surface). Two of these individuals were not exposed to ship noise, and the other four were exposed to both stimuli. These whales reacted mildly to conspecific signals. Seven whales, including the four exposed to the alert stimulus, had no measurable response to either ship sounds or actual vessel noise.
Baleen whale responses to pulsed sound (e.g., seismic airguns) have been studied more thoroughly than responses to continuous sound (e.g., drill rigs). Baleen whales generally tend to avoid operating airguns, but avoidance radii are quite variable. Whales are often reported to show no overt reactions to pulses from large arrays of airguns at distances beyond a few kilometers, even though the airgun pulses remain well above ambient noise levels out to much greater distances (Miller et al., 2005). However, baleen whales exposed to strong noise pulses often react by deviating from their normal migration route (Richardson et al., 1999). Migrating gray and bowhead whales were observed avoiding the sound source by displacing their migration route to varying degrees but within the natural boundaries of the migration corridors (Schick and Urban, 2000; Richardson et al., 1999; Malme et al., 1983). Baleen whale responses to pulsed sound however may depend on the type of activity in which the whales are engaged. Some evidence suggests that feeding bowhead whales may be more tolerant of underwater sound than migrating bowheads (Miller et al., 2005; Lyons et al., 2009; Christie et al., 2010).
Results of studies of gray, bowhead, and humpback whales have determined that received levels of pulses in the 160-170 dB re 1 microPa rms range seem to cause obvious avoidance behavior in a substantial fraction of the animals exposed. In many areas, seismic pulses from large arrays of airguns diminish to those levels at distances ranging from 2.8-9 mi (4.5-14.5 km) from the source. For the much smaller airgun array used during the VSP survey (total discharge volume between 600 and 880 in\3\), the distance to a received level of 160 dB re 1 microPa rms is estimated to be 1.53 mi (2.47 km). Baleen whales within those sound isopleths may show avoidance or other strong disturbance reactions to the airgun array.
Malme et al. (1986, 1988) studied the responses of feeding eastern gray whales to pulses from a single 100 in\3\ airgun off St. Lawrence Island in the northern Bering Sea. They estimated, based on small sample sizes, that 50% of feeding gray whales ceased feeding at an average received pressure level of 173 dB re 1 microPa on an (approximate) rms basis, and that 10% of feeding whales interrupted feeding at received levels of 163 dB. Those findings were generally consistent with the results of experiments conducted on larger numbers of gray whales that were migrating along the California coast and on observations of the distribution of feeding Western Pacific gray whales off Sakhalin Island, Russia, during a seismic survey (Yazvenko et al., 2007).
Data on short-term reactions (or lack of reactions) of cetaceans to impulsive noises do not necessarily provide information about long-term effects. While it is not certain whether impulsive noises affect reproductive rate or distribution and habitat use in subsequent days or years, certain species have continued to use areas ensonified by airguns and have continued to increase in number despite successive years of anthropogenic activity in the area. Behavioral responses to noise exposure are generally highly variable and context dependent (Wartzok et al. 2004). Travelling blue and fin whales (Balaenoptera physalus) exposed to seismic noise from airguns have been reported to stop emitting redundant songs (McDonald et al. 1995; Clark & Gagnon 2006). By contrast, Iorio and Clark (2010) found increased production of transient, non-redundant calls of blue whales during seismic sparker operations. In any event, the brief exposures to sound pulses from the proposed airgun source (the airguns will only be fired for a few hours at a time over the course of 1 to 2 days) are highly unlikely to result in prolonged effects.
Toothed Whales--Most toothed whales have their greatest hearing sensitivity at frequencies much higher than that of baleen whales and may be less responsive to low-frequency sound commonly associated with oil and gas industry exploratory drilling activities. Richardson et al. (1995b) reported that beluga whales did not show any apparent reaction to playback of underwater drilling sounds at distances greater than 656-1,312 ft (200-400 m). Reactions included slowing down, milling, or reversal of course after which the whales continued past the projector, sometimes within 164-328 ft (50-100 m). The authors concluded (based on a small sample size) that the playback of drilling sounds had no biologically significant effects on migration routes of beluga whales migrating through pack ice and along the seaward side of the nearshore lead east of Point Barrow in spring.
At least six of 17 groups of beluga whales appeared to alter their migration path in response to underwater playbacks of icebreaker sound (Richardson et al., 1995b). Received levels from the icebreaker playback were estimated at 78-84 dB in the \1/3\-octave band centered at 5,000 Hz, or 8-14 dB above ambient. If beluga whales reacted to an actual icebreaker at received levels of 80 dB, reactions would be expected to occur at distances on the order of 6.2 mi (10 km). Finley et al. (1990) also reported beluga avoidance of icebreaker activities in the Canadian High Arctic at distances of 22-31 mi (35-50 km). In addition to avoidance, changes in dive behavior and pod integrity were also noted. However,
no icebreakers will be used during this proposed program.
Patenaude et al. (2002) reported changes in beluga whale diving and respiration behavior, and some whales veered away when a helicopter passed at 200 dB re 1 muPa) before exhibiting aversive behaviors.
Pinnipeds--Pinnipeds generally seem to be less responsive to exposure to industrial sound than most cetaceans. Pinniped responses to underwater sound from some types of industrial activities such as seismic exploration appear to be temporary and localized (Harris et al., 2001; Reiser et al., 2009).
Southall et al. (2007) reviewed literature describing responses of pinnipeds to non-pulsed sound and reported that the limited data suggest exposures between approximately 90 and 140 dB generally do not appear to induce strong behavioral responses in pinnipeds exposed to non-pulse sounds in water; no data exist regarding exposures at higher levels. It is important to note that among these studies, there are some apparent differences in responses between field and laboratory conditions. In contrast to the mid-frequency odontocetes, captive pinnipeds responded more strongly at lower levels than did animals in the field. Again, contextual issues are the likely cause of this difference.
Jacobs and Terhune (2002) observed harbor seal reactions to Acoustic Harassment Devices (AHD) (source level in this study was 172 dB) deployed around aquaculture sites. Seals were generally unresponsive to sounds from the AHDs. During two specific events, individuals came within 141 and 144 ft (43 and 44 m) of active AHDs and failed to demonstrate any measurable behavioral response; estimated received levels based on the measures given were approximately 120 to 130 dB.
Costa et al. (2003) measured received noise levels from an Acoustic Thermometry of Ocean Climate (ATOC) program sound source off northern California using acoustic data loggers placed on translocated elephant seals. Subjects were captured on land, transported to sea, instrumented with archival acoustic tags, and released such that their transit would lead them near an active ATOC source (at 939-m depth; 75-Hz signal with 37.5-Hz bandwidth; 195 dB maximum source level, ramped up from 165 dB over 20 min) on their return to a haul-out site. Received exposure levels of the ATOC source for experimental subjects averaged 128 dB (range 118 to 137) in the 60- to 90-Hz band. None of the instrumented animals terminated dives or radically altered behavior upon exposure, but some statistically significant changes in diving parameters were documented in nine individuals. Translocated northern elephant seals exposed to this particular non-pulse source began to demonstrate subtle behavioral changes at exposure to received levels of approximately 120 to 140 dB.
Kastelein et al. (2006) exposed nine captive harbor seals in an approximately 82 x 98 ft (25 x 30 m) enclosure to non-pulse sounds used in underwater data communication systems (similar to acoustic modems). Test signals were frequency modulated tones, sweeps, and bands of noise with fundamental frequencies between 8 and 16 kHz; 128 to 130 3 dB source levels; 1- to 2-s duration 60-80 percent duty cycle; or 100 percent duty cycle. They recorded seal positions and the mean number of individual surfacing behaviors during control periods (no exposure), before exposure, and in 15-min experimental sessions (n = 7 exposures for each sound type). Seals generally swam away from each source at received levels of approximately 107 dB, avoiding it by approximately 16 ft (5 m), although they did not haul out of the water or change surfacing behavior. Seal reactions did not appear to wane over repeated exposure (i.e., there was no obvious habituation), and the colony of seals generally returned to baseline conditions following exposure. The seals were not reinforced with food for remaining in the sound field.
Potential effects to pinnipeds from aircraft activity could involve both acoustic and non-acoustic effects. It is uncertain if the seals react to the sound of the helicopter or to its physical presence flying overhead. Typical reactions of hauled out pinnipeds to aircraft that have been observed include looking up at the aircraft, moving on the ice or land, entering a breathing hole or crack in the ice, or entering the water. Ice seals hauled out on the ice have been observed diving into the water when approached by a low-flying aircraft or helicopter (Burns and Harbo, 1972, cited in Richardson et al., 1995a; Burns and Frost, 1979, cited in Richardson et al., 1995a). Richardson et al. (1995a) note that responses can vary based on differences in aircraft type, altitude, and flight pattern.
Blackwell et al. (2004a) observed 12 ringed seals during low-
altitude overflights of a Bell 212 helicopter at Northstar in June and July 2000 (nine observations took place concurrent with pipe-driving activities). One seal showed no reaction to the aircraft while the remaining 11 (92%) reacted, either by looking at the helicopter (n = 10) or by departing from their basking site (n = 1). Blackwell et al. (2004a) concluded that none of the reactions to helicopters were strong or long lasting, and that seals near Northstar in June and July 2000 probably had habituated to industrial sounds and visible activities that had occurred often during the preceding winter and spring. There have been few systematic studies of pinniped reactions to aircraft overflights, and most of the available data concern pinnipeds hauled out on land or ice rather than pinnipeds in the water (Richardson et al., 1995a; Born et al., 1999).
Reactions of harbor seals to the simulated sound of a 2-megawatt wind power generator were measured by Koschinski et al. (2003). Harbor seals surfaced significantly further away from the sound source when it was active and did not approach the sound source as closely. The device used in that study produced sounds in the frequency range of 30 to 800 Hz, with peak source levels of 128 dB at 1 m at the 80- and 160-Hz frequencies.
Pinnipeds are not likely to show a strong avoidance reaction to the airgun sources proposed for use. 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 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 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 present study area are as strong as those evident in the telemetry study, reactions are expected to be confined to relatively small distances and durations.
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 an intense sound or sound for long duration, 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). However, in the case of the proposed drilling program, animals are not expected to be exposed to levels high enough or durations long enough to result in PTS, as described in detail in the paragraphs below.
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, 2002b, 2003, 2005a, 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. Also, 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 proposed drilling program in Cook Inlet due to the relatively short duration of activities producing these higher level sounds in combination with mitigation and monitoring efforts to avoid such effects.
Non-Auditory Physical Effects
Non-auditory physical effects might occur in marine mammals exposed to strong underwater 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 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. Marine mammals 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. The source level of the jack-up rig is not loud enough to induce PTS or likely even 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.
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, which are not proposed for use during this program. For the most part, only low-level continuous sounds would be produced during the drilling program as impact hammering and VSP would occur for only short periods of time and most of the sound produced would be from the ongoing operation/drilling. In addition, marine mammals that show
behavioral avoidance of industry activities, including belugas and some pinnipeds, are especially unlikely to incur non-auditory impairment or other physical effects.
Stranding and Mortality
Marine mammals close to underwater detonations of high explosive 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 airgun pulses, even in the case of large airgun arrays. Additionally, the airguns used during VSP are used for short periods of time. The continuous sounds produced by the drill rig are also far less energetic.
It should be noted that strandings known, or thought, to be related to sound exposure have not been recorded for marine mammal species in Cook Inlet. 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. NMFS does not expect any marine mammals will incur serious injury or mortality in Cook Inlet or strand as a result of the proposed drilling program.
Vessel activity and noise associated with vessel activity will temporarily increase in the action area during BlueCrest's oil and gas production drilling program as a result of the operation of a jack-up drill rig and the use of tow and other support vessels. While under tow, the rig and the tow vessels move at slow speeds (2-4 knots). The support barges supplying pipe to the drill rig can typically run at 7-8 knots but may move slower inside Cook Inlet. Based on this information, NMFS does not anticipate and does not propose to authorize take from vessel 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., 1995a). 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., 1995a). Reactions to vessels depends on whale activities and experience, habitat, boat type, and boat behavior (Richardson et al., 1995a) 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., 1995a). Generally, sea lions in water show tolerance to close and frequently 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., 1995a).
Oil Spill and Discharge Impacts
As noted above, the specified activity involves towing the rig, drilling of wells, and other associated support activities in lower Cook Inlet during the 2016 open water season. The primary stressors to marine mammals that are reasonably expected to occur will be acoustic in nature. The likelihood of a large oil spill occurring during BlueCrest's proposed drilling program is remote and effects from an event of this nature are not authorized. Offshore oil spill records in Cook Inlet during 1994-2011 show three spills during oil exploration (ADNR Division of Oil and Gas, 2011 unpub. data): Two oil spills at the UNOCAL Dillion Platform in June 2011 (two gallons) and December 2001 (three gallons); and one oil spill at the UNOCAL Monopod Platform in January 2002 (one gallon). During this same time period, 71 spills occurred offshore in Cook Inlet during oil production. Most spills ranged from 0.0011 to 1 gallon (42 spills), and only three spills were larger than 200 gallons: 210 gallons in July 2001 at the Cook Inlet Energy Stewart facility; 250 gallons in February 1998 at the King Salmon platform; and 504 gallons in October 1999 at the UNOCAL Dillion platform. All 71 crude oil spills from the offshore platforms, both exploration and production, totaled less than 2,140 gallons. Based on historical data, most oil spills have been small. Moreover, during more than 60 years of oil and gas exploration and development in Cook Inlet, there has not been a single oil well blowout, making it difficult to assign a specific risk factor to the possibility of such an event in Cook Inlet. However, the probability of such an event is thought to be extremely low.
BlueCrest will have various measures and protocols in place that will be implemented to prevent oil releases from the wellbore. BlueCrest has planned formal routine rig maintenance and surveillance checks, as well as normal inspection and equipment checks to be conducted on the jack-up rig daily. The following steps will be in place to prevent oil from entering the water:
Required inspections will follow standard operating procedures.
Personnel working on the rig will be directed to report any unusual conditions to appropriate personnel.
Oily equipment will be regularly wiped down with oil absorbent pads to collect free oil. Drips and small spillage from equipment will be controlled through use of drip pans and oil absorbent drop clothes.
Oil absorbent materials used to contain oil spills or seeps will be collected and disposed of in sealed plastic bags or metal drums and closed containers.
The platform surfaces will be kept clean of waste materials and loose debris on a daily basis.
Remedial actions will be taken when visual inspections indicate deterioration of equipment (tanks) and/or their control systems.
Following remedial work, and as appropriate, tests will be conducted to determine that the systems function correctly.
Drilling and completion fluids provide primary well control during drilling, work over, or completion operations. These fluids are designed to exert hydrostatic pressure on the wellbore that exceeds the pore pressures within the subsurface formations. This prevents undesired fluid flow into the wellbore. Surface mounted blowout preventer (BOP) equipment provides secondary well control. In the event that primary well control is lost, this surface equipment is used to contain the influx of formation fluid and then safely circulate it out of the wellbore.
The BOP is a large, specialized valve used to seal, control, and monitor oil and gas wells. BOPs come in variety of styles, sizes, and pressure ratings. For Cook Inlet, the BOP equipment used by BlueCrest will consist of:
Three BOPs pressure safety levels of: (1) 5,000 pounds per square inch (psi), (2) 10,000 psi, and (3) 15,000 psi;
A minimum of three 35 cm (13\5/8\ in), 10,000 psi WP ram type preventers;
One 35 cm (13\5/8\ in) annular preventer;
Choke and kill lines that provide circulating paths from/
to the choke manifold;
A two choke manifold that allows for safe circulation of well influxes out of the well bore; and
A hydraulic control system with accumulator backup closing.
The wellhead, associated valves, and control systems provide blowout prevention during well production. These systems provide several layers of redundancy to ensure pressure containment is maintained. Well control planning is performed in accordance with Alaska Oil and Gas Conservation Commission (AOGCC) and the Department of the Interior's Bureau of Safety and Environment Enforcement (BSEE) regulations. The operator's policies and recommended practices are, at a minimum, equivalent to BSEE regulations. BOP test drills are performed on a frequent basis to ensure the well will be shut in quickly and properly. BOP testing procedures will meet American Petroleum Institute Recommended Practice No. 53 and AOGCC specifications. The BOP tests will be conducted with a nonfreezing fluid when the ambient temperature around the BOP stack is below 0 degC (32 degF). Tests will be conducted at least weekly and before drilling out the shoe of each casing string. The AOGCC will be contacted before each test is conducted, and will be onsite during BOP tests unless an inspection waiver is approved.
BlueCrest developed an Oil Discharge Prevention and Contingency Plan (ODPCP) and has submitted it for approval to Alaska's Department of Environmental Conservation (ADEC). NMFS reviewed the previous ODPCP covering the Cosmopolitan drilling program (prepared by Buccaneer Alaska Operations LLC) during the ESA consultation process for Cosmopolitan leases and found that with implementation of the safety features mentioned above that the risk of an oil spill was discountable. As an oil spill is not a likely occurrence, it is not a component of BlueCrest's specified activity for which NMFS is proposing to authorize take.
Anticipated Effects on Marine Mammal Habitat
The primary potential impacts to marine mammals and other marine species are associated with elevated sound levels produced by the drilling program (i.e. towing of the drill rig and the airguns). However, other potential impacts are also possible to the surrounding habitat from physical disturbance, discharges, and an oil spill (which we do not anticipate or authorize). This section describes the potential impacts to marine mammal habitat from the specified activity, including impacts on fish and invertebrate species typically preyed upon by marine mammals in the area.
Common Marine Mammal Prey in the Proposed Drilling Area
Fish are the primary prey species for marine mammals in Cook Inlet. Beluga whales feed on a variety of fish, shrimp, squid, and octopus (Burns and Seaman, 1986). Common prey species in Knik Arm 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 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 From Seafloor Disturbance on Marine Mammal Habitat
There is a possibility of seafloor disturbance or increased turbidity in the vicinity of the drill sites. Seafloor disturbance could occur with bottom founding of the drill rig legs and anchoring system. These activities could lead to direct effects on bottom fauna, through either displacement or mortality. Increase in suspended sediments from seafloor disturbance also has the potential to indirectly affect bottom fauna and fish. The amount and duration of disturbed or turbid conditions will depend on sediment material.
The potential direct habitat impact by the BlueCrest drilling operation is limited to the actual drill-rig footprint defined as the area occupied and enclosed by the drill-rig legs. The jack-up rig will temporarily disturb one offshore location in lower Cook Inlet, where the wells are proposed to be drilled. Bottom disturbance would occur in the area where the three legs of the rig would be set down and where the actual wells would be drilled. The jack-up drill rig footprint would occupy three steel piles at 14 m (46 ft) diameter. The well casing would be a 76 cm (30 in) diameter pipe extending from the seafloor to the rig floor. The casing would only be in place during drilling activities at each potential well location. The total area of disturbance was calculated as 0.54 acres during the land use permitting process. The collective 2-acre footprint of the wells represents a very small fraction of the 7,300 square mile Cook Inlet surface area. Potential damage to the Cook Inlet benthic community will be limited to the actual surface area of the three spudcans (1,585 square feet each or 4,755 square feet total) that form the ``foot'' of each leg. Given the high tidal energy at the well site locations, drilling footprints are not expected to support benthic communities equivalent to shallow lower energy sites found in nearshore waters where harbor seals mostly feed. The presence of the drill rig is not expected to result in direct loss of marine mammal habitat.
Potential Impacts From Sound Generation
With regard to fish as a prey source for odontocetes and seals, 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 noise level.
Fish 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. Fish 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).
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). Generally, most fish have their best hearing in the low-frequency range (i.e., less than 1 kHz). Even though some fish are able to detect sounds in the ultrasonic frequency range, the thresholds at these higher frequencies tend to be considerably higher than those at the lower end of the auditory frequency range.
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.
Potential effects of exposure to continuous sound on marine fish include TTS, physical damage to the ear region, physiological stress responses, and behavioral responses such as startle response, alarm response, avoidance, and perhaps lack of response due to masking of acoustic cues. Most of these effects appear to be either temporary or intermittent and therefore probably do not significantly impact the fish at a population level. The studies that resulted in physical damage to the fish ears used noise exposure levels and durations that were far more extreme than would be encountered under conditions similar to those expected during BlueCrest's proposed exploratory drilling activities.
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), such as the type of sound that will be produced by the drillship, 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 capeline 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., 1995a). (Based on models, the 160 dB radius for the jack-up rig would extend approximately 33 ft 10 m; therefore, fish would need to be in close proximity to the drill rig for the noise to be audible). In calm weather, ambient noise levels in audible parts of the spectrum lie between 60 dB to 100 dB.
BlueCrest also proposes to conduct VSP surveys with an airgun array for a short period of time during the drilling season (only a few hours over 1-2 days over the course of the entire proposed drilling program). Airguns produce impulsive sounds as opposed to continuous sounds at the source. Short, sharp sounds can cause overt or subtle changes in fish behavior. Chapman and Hawkins (1969) tested the reactions of whiting (hake) in the field to an airgun. When the airgun was fired, the fish dove from 82 to 180 ft (25 to 55 m) depth and formed a compact layer. The whiting dove when received sound levels were higher than 178 dB re 1 microPa (Pearson et al., 1992).
Pearson et al. (1992) conducted a controlled experiment to determine effects of strong noise pulses on several species of rockfish off the California coast. They used an airgun with a source level of 223 dB re 1 microPa. They noted:
Startle responses at received levels of 200-205 dB re 1 microPa and above for two sensitive species, but not for two other species exposed to levels up to 207 dB;
Alarm responses at 177-180 dB for the two sensitive species, and at 186 to 199 dB for other species;
An overall threshold for the above behavioral response at about 180 dB;
An extrapolated threshold of about 161 dB for subtle changes in the behavior of rockfish; and
A return to pre-exposure behaviors within the 20-60 minute exposure period.
In summary, fish often react to sounds, especially strong and/or intermittent sounds of low frequency. Sound pulses at received levels of 160 dB re 1 microPa may cause subtle changes in behavior. Pulses at levels of 180 dB may cause noticeable changes in behavior (Chapman and Hawkins, 1969; Pearson et al., 1992; Skalski et al., 1992). It also appears that fish often habituate to repeated strong sounds rather rapidly, on time scales of minutes to an hour. However, the habituation does not endure, and resumption of the strong sound source may again elicit disturbance responses from the same fish. Underwater sound levels from the drill rig and other vessels produce sounds lower than the response threshold reported by Pearson et al. (1992), and are not likely to result in major effects to fish near the proposed drill site.
Based on a sound level of approximately 140 dB, there may be some avoidance by fish of the area near
the jack-up while drilling, around the rig under tow, and around other support and supply vessels when underway. Any reactions by fish to these sounds will last only minutes (Mitson and Knudsen, 2003; Ona et al., 2007) longer than the vessel is operating at that location or the drill rig is drilling. Any potential reactions by fish would be limited to a relatively small area within about 33 ft (10 m) of the drill rig during drilling. Avoidance by some fish or fish species could occur within portions of this area.
The lease areas do not support major populations of cod, Pollock, and sole, although all four salmon species and smelt may migrate through the area to spawning rivers in upper Cook Inlet (Shields and Dupuis, 2012). Residency time for the migrating finfish in the vicinity of an operating platform would be short-term, limiting fish exposure to noise associated with the proposed drilling program.
Some of the fish species found in Cook Inlet are prey sources for odontocetes and pinnipeds. A reaction by fish to sounds produced by BlueCrest's proposed operations would only be relevant to marine mammals if it caused concentrations of fish to vacate the area. Pressure changes of sufficient magnitude to cause that type of reaction would probably occur only very close to the sound source, if any would occur at all due to the low energy sounds produced by the majority of equipment proposed for use. Impacts on fish behavior are predicted to be inconsequential. Thus, feeding odontocetes and pinnipeds would not be adversely affected by this minimal loss or scattering, if any, which is not expected to result in reduced prey abundance. The proposed drilling area is not a common feeding area for baleen whales.
Potential Impacts From Drilling Discharges
The drill rig Spartan151 will operate under the Alaska Pollutant Discharge Elimination System (APDES) general permit AKG-31-5021 for wastewater discharges (ADEC, 2012). This permit authorizes discharges from oil and gas extraction facilities engaged in exploration under the Offshore and Coastal Subcategories of the Oil and Gas Extraction Point Source Category (40 CFR part 435). Twelve effluents are authorized for discharge into Cook Inlet once ADEC discharge limits have been met. The authorized discharges include: Drilling fluids and drill cuttings, deck drainage, sanitary waste, domestic waste, blowout preventer fluid, boiler blow down, fire control system test water, uncontaminated ballast water, bilge water, excess cement slurry, mud cuttings cement at sea floor, and completion fluids. Areas prohibited from discharge in the Cook Inlet are 10-meter (33-foot) isobaths, 5-meter (16-foot) isobaths, and other geographic area restrictions (AKG-31-5021.I.C.). The Spartan151 is also authorized under EPA's Vessel General Permit for deck wash down and runoff, gray water, and gray water mixed with sewage discharges. The effluent limits and related requirements for these discharges in the Vessel General Permit are to minimize or eliminate to the extent achievable using control measures (best management practices) (EPA, 2011).
Drilling wastes include drilling fluids, known as mud, rock cuttings, and formation waters. Drilling wastes (non-hydrocarbon) will be discharged to the Cook Inlet under the approved APDES general permit. Drilling wastes (hydrocarbon) will be delivered to an onshore permitted location for disposal. During drilling, the onsite tool pusher/driller and qualified mud engineers will direct and maintain desired mud properties, and maintain the quantities of basic mud materials on site as dictated by good oilfield practice. BlueCrest will follow best management practices to ensure that a sufficient inventory of barite and lost circulation materials are maintained on the drilling vessel to minimize the possibility of a well upset and the likelihood of a release of pollutants to Cook Inlet waters. These materials can be re-supplied, if required, using the supply vessel. Because adverse weather could prevent immediate re-supply, sufficient materials will be available on board to completely rebuild the total circulating volume. BlueCrest will conduct an Environmental Monitoring Study of relevant hydrographic, sediment hydrocarbon, and heavy metal data from surveys conducted before and during drilling mud disposal and up to a least one year after drilling operations cease in accordance with the APDES general permit for discharges of drilling muds and cuttings.
Non-drilling wastewater includes deck drainage, sanitary waste, domestic waste, blowout preventer fluid, boiler blow down, fire control test water, bilge water, non-contact cooling water, and uncontaminated ballast water. Non-drilling wastewater will be discharged into Cook Inlet under the approved APDES general permit or delivered to an onshore permitted location for disposal. Mud cuttings will be constantly tested. No hydrocarboned muds will be permitted to be discharged into Cook Inlet. They will be hauled offsite. Solid waste (e.g., packaging, domestic trash) will be classified, segregated, and labeled as general, universal, and Resource Conservation and Recovery Act exempt or non-exempt waste. It will be stored in containers at designated accumulation areas. Then, it will be packaged and palletized for transport to an approved on-shore disposal facility. No hazardous wastes should be generated as a result of this project. However, if any hazardous wastes were generated, it would be temporarily stored in an onboard satellite accumulation area and then transported offsite for disposal at an approved facility.
With oil and gas platforms presently operating in Cook Inlet, there is concern for continuous exposure to potentially toxic heavy metals and metalloids (i.e., mercury, lead, cadmium, copper, zinc, and arsenic) that are associated with oil and gas development and production. These elements occur naturally in the earth's crust and the oceans but many also have anthropogenic origins from local sources of pollution or from contamination from atmospheric distribution.
Discharging drill cuttings or other liquid waste streams generated by the drilling vessel could potentially affect marine mammal habitat. Toxins could persist in the water column, which could have an impact on marine mammal prey species. However, despite a considerable amount of investment in research on exposures of marine mammals to organochlorines or other toxins, there have been no marine mammal deaths in the wild that can be conclusively linked to the direct exposure to such substances (O'Shea, 1999).
Drilling muds and cuttings discharged to the seafloor can lead to localized increased turbidity and increase in background concentrations of barium and occasionally other metals in sediments and may affect lower trophic organisms. Drilling muds are composed primarily of bentonite (clay), and the toxicity is therefore low. Heavy metals in the mud may be absorbed by benthic organisms, but studies have shown that heavy metals do not bio-magnify in marine food webs (Neff et al., 1989). Effects on benthic communities are nearly always restricted to a zone within about 328 to 492 ft (100 to 150 m) of the discharge, where cuttings accumulations are greatest. Discharges and drill cuttings could impact fish by displacing them from the affected area.
Levels of heavy metals and other elements (cadmium, mercury, selenium, vanadium, and silver) were generally
lower in the livers of Cook Inlet beluga whales than those of other beluga whale stocks, while copper was higher (Becker et al., 2001). Hepatic methyl mercury levels were similar to those reported for other beluga whales (Geraci and St. Aubin, 1990). The relatively high hepatic concentration of silver found in the eastern Chukchi Sea and Beaufort Sea stocks of belugas was also found in the Cook Inlet animals, suggesting a species-specific phenomenon. However, because of the limited discharges, no water quality impacts are anticipated that would negatively affect habitat for Cook Inlet marine mammals.
Potential Impacts From Drill Rig Presence
The horizontal dimensions of the Spartan151 jack-up rig are 147 ft by 30 ft. The dimensions of the drill rig (less than one football field on either side) are not significant enough to cause a large-scale diversion from the animals' normal swim and migratory paths. Any deflection of marine mammal species due to the physical presence of the drill rig would be very minor. The drill rig's physical footprint is small relative to the size of the geographic region it will occupy and will likely not cause marine mammals to deflect greatly from their typical migratory route. Also, even if animals may deflect because of the presence of the drill rig, Cook Inlet is much larger in size than the length of the drill rig (many dozens of miles vs. less than one football field), and animals would have other means of passage around the drill rig. In sum, the physical presence of the drill rig is not likely to cause a significant deflection to migrating marine mammals.
Potential Impacts From an Oil Spill
As noted above, an oil spill is not a likely occurrence, it is not a component of BlueCrest's specified activity for which NMFS is proposing to authorize take. Also, as noted above, NMFS previously considered potential effects of an oil spill in the unlikely event that it happened and determined the effects discountable, and there has been no new information that would change this determination at this time.
Based on the consideration of potential types of impacts to marine mammal habitat, and taking into account the very low potential for a large or very large oil spill, overall, the proposed specified activity is not expected to cause significant impacts on habitats used by the marine mammal species in the proposed project area, including the food sources that they utilize.
In order to issue an incidental take authorization (ITA) under section 101(a)(5)(D) 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). Later in this document in the ``Proposed Incidental Harassment Authorization'' section, NMFS lays out the proposed conditions for review, as they would appear in the final IHA (if issued).
The drill rig does not emit sound levels that would result in Level A harassment (injury), which NMFS typically requires applicants to avoid through mitigation (such as shutdowns). For continuous sounds, such as those produced by drilling operations and rig tow, NMFS uses a received level of 120-dB (rms) for the onset of Level B harassment. For impulse sounds, such as those produced by the airgun array during the VSP surveys or the impact hammer during drive pipe driving, NMFS uses a received level of 160-dB (rms) for the onset of Level B harassment. The current Level A (injury) harassment threshold is 180 dB (rms) for cetaceans and 190 dB (rms) for pinnipeds. Table 2 outlines the various applicable radii that inform mitigation.
Table 2--Applicable Mitigation and Shutdown Radii for BlueCrest's Proposed Lower Cook Inlet Drilling Program
190 dB radius 180 dB radius 160 dB radius 120 dB radius
Impact hammer during drive pipe 60 m (200 ft)............... 250 m (820 ft).............. 1.6 km (1 mi).............. NA.
Airguns during VSP................ 120 m (394 ft).............. 240 m (787 ft).............. 2.5 km (1.55 mi)........... NA.
NA = Not applicable.
Mitigation Measures Proposed by BlueCrest
For the proposed mitigation measures, BlueCrest listed the following protocols to be implemented during its drilling program in Cook Inlet.
Drive Pipe Hammering Measures
Two protected species observers (PSOs), working alternate shifts, will be stationed aboard the drill rig during all pipe driving activities at the well. Standard marine mammal observing field equipment will be used, including reticule binoculars (10x42), big-eye binoculars (30x), inclinometers, and range finders. The PSOs will be stationed as close to the well head as safely possible, and will observe from the drill rig during this 2-3 day portion of the proposed program out to the 160 dB (rms) radius of 1.6 km (1 mi). Drive pipe hammering will be limited to daylight hours, and when sea conditions are light; therefore, marine mammal observation conditions will be generally good. If cetaceans enter within the 180 dB (rms) radius of 250 m (820 ft), or if pinnipeds enter within the 190 dB (rms) radius of 60 m (200 ft), then use of the impact hammer will cease. If any beluga whales, or any cetacean for which take has not been authorized, are detected entering the 160 dB disturbance zone activities will cease until the animal has been visually confirmed to clear the zone or is unseen for at least 30 minutes. Following a shutdown of impact hammering activities, the applicable zones must be clear of marine mammals for at least 30 minutes prior to restarting activities.
BlueCrest proposes to follow a ramp-up procedure during impact hammering activities. PSOs will visually monitor out to the 160 dB radius for at least 30 minutes prior to the initiation of activities. If no marine mammals are detected during that time, then BlueCrest can initiate impact hammering using a ``soft start'' technique. Hammering will begin with an initial set of three strikes at 40 percent energy followed by a 1 min waiting period, then two subsequent three-strike sets. This ``soft-start'' procedure will be implemented anytime impact hammering has ceased for 30 minutes or more. Impact hammer ``soft-
start'' will not be required if the hammering downtime is for less than 30 minutes and visual surveys are continued throughout the silent period
and no marine mammals are observed in the applicable zones during that time. Monitoring will occur during all hammering sessions.
VSP Airgun Measures
As with pipe driving, two PSOs will observe from the drill rig during this 1-2 day portion of the proposed program out to the 160 dB radius of 2.5 km (1.55 mi). Standard marine mammal observing field equipment will be used, including reticule binoculars (10x42), big-eye binoculars (30x), inclinometers, and range finders. Monitoring during zero-offset VSP will be conducted by two PSOs operating from the drill rig. During walk-away VSP operations, an additional two PSOs will monitor from the seismic source vessel. VSP activities will be limited to daylight hours, and when sea conditions are light; therefore, marine mammal observation conditions will be generally good. If cetaceans enter within the 180 dB (rms) radius of 240 m (787 ft) or if pinnipeds enter within the 190 dB (rms) radius of 120 m (394 ft), then use of the airguns will cease. If any beluga whales, or any cetacean for which take has not been authorized, are detected entering the 160 dB disturbance zone, activities will cease until the animal has been visually confirmed to clear the zone or is unseen for at least 30 minutes. Following a shutdown of airgun operations, the applicable zones must be clear of marine mammals for at least 30 minutes prior to restarting activities.
BlueCrest proposes to follow a ramp-up procedure during airgun operations. PSOs will visually monitor out to the 160 dB radius for at least 30 minutes prior to the initiation of activities. If no marine mammals are detected during that time, then BlueCrest can initiate airgun operations using a ``ramp-up'' technique. Airgun operations will begin with the firing of a single airgun, which will be the smallest gun in the array in terms of energy output (dB) and volume (in\3\). Operators will then continue ramp-up by gradually activating additional airguns over a period of at least 30 minutes (but not longer than 40 minutes) until the desired operating level of the airgun array is obtained. This ramp-up procedure will be implemented anytime airguns have not been fired for 30 minutes or more. Airgun ramp-up will not be required if the airguns have been off for less than 30 minutes and visual surveys are continued throughout the silent period and no marine mammals are observed in the applicable zones during that time. Monitoring will occur during all airgun usage.
Oil Spill Plan
BlueCrest developed an Oil Discharge Prevention and Contingency Plan (ODPCP) and has submitted it for approval to Alaska's Department of Environmental Conservation (ADEC). NMFS reviewed the previous ODPCP covering the Cosmopolitan drilling program (prepared by Buccaneer Alaska Operations LLC) during the ESA consultation process for Cosmopolitan leases and found that with implementation of the safety features mentioned above that the risk of an oil spill was discountable. The new ODPCP for operations under BlueCrest was approved on March 30, 2016.
Pollution Discharge Plan
When the drill rig is towed or otherwise floating it is classified as a vessel (like a barge). During those periods, it is covered under a form of National Pollutant Discharge Elimination System permit known as a Vessel General Permit. This permit remains federal and is a ``no discharge permit,'' which allows for the discharge of storm water and closed system fire suppression water but no other effluents.
When the legs are down, the drill rig becomes a facility. During those periods, it is covered under an approved APDES. Under the APDES, certain discharges are permitted. However, BlueCrest is not permitted to discharge gray water, black water, or hydrocarboned muds; they are all hauled off and not discharged.
Mitigation Measures Proposed by NMFS
NMFS proposes that: during rig towing operations, speed will be reduced to 8 knots or less, as safety allows, at the approach of any whales or Steller sea lions within 2,000 ft (610 m) of the towing operations; and when BlueCrest utilizes helicopters for support operations that the helicopters must maintain an altitude of at least 1,000 ft (305 m), except during takeoffs, landings, or emergency situations.
NMFS has carefully evaluated BlueCrest's proposed mitigation measures and considered a range of other measures in the context of ensuring that NMFS prescribes the means of affecting the least practicable impact on the affected marine mammal species and stocks and their habitat. Our evaluation of potential measures included consideration of the following factors in relation to one another:
The manner in which, and the degree to which, the successful implementation of the measures are expected to minimize adverse impacts to marine mammals;
The proven or likely efficacy of the measures to minimize adverse impacts as planned; and
The practicability of the measures 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:
Avoidance or minimization of injury or death of marine mammals wherever possible (goals 2, 3, and 4 may contribute to this goal).
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, impact hammers, drill rig deep well pumps, 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).
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 impact hammers, drill rig deep well pumps, 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).
A reduction in the intensity of exposures (either total number or number at biologically important time or location) to received levels of seismic airguns impact hammers, drill rig deep well pumps, 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).
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.
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 proposed measures, as well as other measures proposed by NMFS, NMFS has preliminarily determined that implementation of these mitigation measures provide the means of effecting
the least practicable impact on marine mammals species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance.
Proposed 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 proposed action area. BlueCrest submitted information regarding marine mammal monitoring to be conducted during the proposed drilling program as part of the IHA application. That information can be found in the Appendix of their application. The monitoring measures may be modified or supplemented based on comments or new information received from the public during the public comment period.
Monitoring measures proposed by the applicant or prescribed by NMFS should accomplish one or more of the following top-level goals:
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.
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).
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).
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).
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).
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.
An increase in our understanding of the effectiveness of mitigation and monitoring measures.
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.
Proposed Monitoring Measures
PSOs will be required to monitor the area for marine mammals aboard the drill rig during drilling operations, drive pipe hammering, and VSP operations. Standard marine mammal observing field equipment will be used, including reticule binoculars, Big-eye binoculars, inclinometers, and range-finders. Drive pipe hammering and VSP operations will not occur at night, so PSOs will not be on watch during nighttime. At least one PSO will be on duty at all times when operations are occurring. Shifts shall not last more than 4 hours, and PSOs will not observe for more than 12 hours in a 24-hour period.
Sound Source Verification Monitoring
Sound source verification (SSV) measurements have already been conducted for the Spartan151 and all other sound generating activities planned at the Cosmopolitan well site by MAI (2011). No SSV measurements are planned at this time for the 2016 program.
90-Day Technical Report
Daily field reports will be prepared that include daily activities, marine mammal monitoring efforts, and a record of the marine mammals and their behaviors and reactions observed that day. These daily reports will be used to help generate the 90-day technical report. A report will be due to NMFS no later than 90 days after the expiration of the IHA (if issued). The Technical Report will include the following:
Summaries of monitoring effort (e.g., total hours, total distances, and marine mammal distribution through the study period, accounting for sea state and other factors affecting visibility and detectability of marine mammals).
Analyses of the effects of various factors influencing detectability of marine mammals (e.g., sea state, number of observers, and fog/glare).
Species composition, occurrence, and distribution of marine mammal sightings, including date, water depth, numbers, age/
size/gender categories (if determinable), group sizes, and ice cover.
Analyses of the effects of operations.
Sighting rates of marine mammals (and other variables that could affect detectability), such as: (i) Initial sighting distances versus operational activity state; (ii) closest point of approach versus operational activity state; (iii) observed behaviors and types of movements versus operational activity state; (iv) numbers of sightings/individuals seen versus operational activity state; (v) distribution around the drill rig versus operational activity state; and (vi) estimates of take by Level B harassment based on presence in the Level B harassment zones.
Notification of Injured or Dead Marine Mammals
In the unanticipated event that BlueCrest's specified activity clearly causes the take of a marine mammal in a manner prohibited by the IHA (if issued), such as an injury (Level A harassment), serious injury or mortality (e.g., ship-strike, gear interaction, and/or entanglement), BlueCrest would immediately cease the specified activities and immediately report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources, NMFS, the Alaska Region Protected Resources Division, NMFS, and the Alaska Regional Stranding Coordinators. The report would include the following information:
Time, date, and location (latitude/longitude) of the incident;
Name and type of vessel involved;
Vessel's speed during and leading up to the incident;
Description of the incident;
Status of all sound source use in the 24 hours preceding the incident;
Environmental conditions (e.g., wind speed and direction, Beaufort sea state, cloud cover, and visibility);
Description of all marine mammal observations in the 24 hours preceding the incident;
Species identification or description of the animal(s) involved;
Fate of the animal(s); and
Photographs or video footage of the animal(s) (if equipment is available).
Activities would not resume until NMFS is able to review the circumstances of the prohibited take. NMFS would work with BlueCrest to determine what is necessary to minimize the likelihood of further prohibited take and ensure MMPA compliance. BlueCrest would not be able to resume their activities until notified by NMFS via letter, email, or telephone.
In the event that BlueCrest discovers an injured or dead marine mammal, and the lead PSO determines that the cause of the injury or death is unknown and the death is relatively recent (i.e., in less than a moderate state of decomposition as described in the next paragraph), BlueCrest would immediately report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources, NMFS, the Alaska Region Protected Resources Division, NMFS, and the NMFS Alaska Stranding Hotline and/or by email to the Alaska Regional Stranding Coordinators. The report would include the same information identified in the paragraph above. If the observed marine mammal is dead, activities would be able to continue while NMFS reviews the circumstances of the incident. If the observed marine mammal is injured, measures described below must be implemented. NMFS would work with BlueCrest to determine whether modifications in the activities are appropriate.
In the event that BlueCrest discovers an injured or dead marine mammal, and the lead PSO determines that the injury or death is not associated with or related to the activities authorized in the IHA (e.g., carcass with moderate to advanced decomposition, or scavenger damage), BlueCrest would report the incident to the Chief of the Permits and Conservation Division, Office of Protected Resources, NMFS, the Alaska Region Protected Resources Division, NMFS, and the NMFS Alaska Stranding Hotline and/or by email to the Alaska Regional Stranding Coordinators, within 24 hours of the discovery. BlueCrest would provide photographs or video footage (if available) or other documentation of the stranded animal sighting to NMFS and the Marine Mammal Stranding Network. If the observed marine mammal is dead, activities may continue while NMFS reviews the circumstances of the incident. If the observed marine mammal is injured, measures described below must be implemented. In this case, NMFS will notify BlueCrest when activities may resume.
Injured Marine Mammals
The following describe the specific actions BlueCrest must take if a live marine mammal stranding is reported in Cook Inlet coincident to, or within 72 hours of seismic activities involving the use of airguns. A live stranding event is defined as a marine mammal: (i) On a beach or shore of the United States and unable to return to the water; (ii) on a beach or shore of the United States and, although able to return to the water, is in apparent need of medical attention; or (iii) in the waters under the jurisdiction of the United States (including navigable waters) but is unable to return to its natural habitat under its own power or without assistance.
The shutdown procedures described here are not related to the investigation of the cause of the stranding and their implementation is in no way intended to imply that BlueCrest's airgun operation is the cause of the stranding. Rather, shutdown procedures are intended to protect marine mammals exhibiting indicators of distress by minimizing their exposure to possible additional stressors, regardless of the factors that initially contributed to the stranding.
Should BlueCrest become aware of a live stranding event (from NMFS or another source), BlueCrest must immediately implement a shutdown of the airgun array. A shutdown must be implemented whenever the animal is within 5 km of the airgun array. Shutdown procedures will remain in effect until NMFS determines that, and advises BlueCrest that, all live animals involved in the stranding have left the area (either of their own volition or following herding by responders).
Within 48 hours of the notification of the live stranding event, BlueCrest must inform NMFS where and when they were operating airguns and at what discharge volumes. BlueCrest must appoint a contact who can be reached 24/7 for notification of live stranding events. Immediately upon notification of the live stranding event, this person must order the immediate shutdown of the airguns. These conditions are in addition to those noted above.
Estimated Take by Incidental Harassment
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. Only take by Level B behavioral harassment of some species is anticipated as a result of the proposed drilling program. Anticipated impacts to marine mammals are associated with noise propagation from the sound sources (e.g., drill rig and tow, airguns, and impact hammer) used in the drilling program. Additional disturbance to marine mammals may result from visual disturbance of the drill rig or support vessels. No take is expected to result from vessel strikes because of the slow speed of the vessels (2-4 knots while rig is under tow; 7-8 knots for supply barges).
BlueCrest requests authorization to take nine marine mammal species by Level B harassment. These nine marine mammal species are: beluga whale; humpback whale; gray whale; minke whale; killer whale; harbor porpoise; Dall's porpoise; Steller sea lion; and harbor seal. In April 2013, NMFS Section 7 ESA biologists concurred that Buccaneer's proposed Cosmopolitan exploratory drilling program was not likely to adversely affect Cook Inlet beluga whales or beluga whale critical habitat. Since the sale of the Cosmopolitan leases from Buccaneer to BlueCrest and the slight change in the program (e.g., drilling of up to three wells instead of two), Mitigation measures requiring shutdowns of activities before belugas enter the Level B harassment zones will be required in any issued IHA. Therefore, the potential for take of belugas would be eliminated; however, a small number of takes are included to cover any unexpected or accidental take.
As noted previously in this document, for continuous sounds, for impulse sounds such as those produced by the airgun array during the VSP surveys or
the impact hammer during drive pipe hammering, NMFS uses a received level of 160-dB (rms) to indicate the onset of Level B harassment. The current Level A (injury) harassment threshold is 180 dB (rms) for cetaceans and 190 dB (rms) for pinnipeds. Table 3 outlines the current acoustic criteria.
Table 3--Acoustic Exposure Criteria Used by NMFS
Criterion Criterion definition Threshold
Level A Harassment (Injury). Permanent Threshold 180 dB re 1 microPa-
Shift (PTS) (Any m (cetaceans)/190
level above that dB re 1 micro-m
which is known to (pinnipeds) root
cause TTS). mean square (rms).
Level B Harassment.......... Behavioral 160 dB re 1 microPa-
Disruption (for m (rms).
Section 6 of BlueCrest's application contains a description of the methodology used by BlueCrest to estimate takes by harassment, including calculations for the 120 dB (rms) and 160 dB (rms) isopleths and marine mammal densities in the areas of operation (see ADDRESSES), which is also provided in the following sections. NMFS verified BlueCrest's methods, and used the density and sound isopleth measurements in estimating take. However, NMFS also include a duration factor in the estimates presented below, which is not included in BlueCrest's application.
The proposed take estimates presented in this section were calculated by multiplying the best available density estimate for the species (from NMFS aerial surveys 2005-2014) by the area of ensonification for each type of activity by the total number of days that each activity would occur. While the density and sound isopleth data helped to inform the decision for the proposed estimated take levels for harbor porpoises and harbor seals, NMFS also considered the information regarding marine mammal sightings during BlueCrest's 2013 Cosmopolitan #A-1 drilling program. Additional detail is provided next.
Drive Pipe Hammering
The Delmar D62-22 diesel impact hammer proposed to be used by BlueCrest to drive the 30-inch drive pipe was previously acoustically measured by Blackwell (2005) in upper Cook Inlet. She found that sound exceeding 190 dB Level A noise limits for pinnipeds extend to about 200 ft (60 m), and 180 dB Level A impacts to cetaceans to about 820 ft (250 m). Level B disturbance levels of 160 dB extended to just less than 1 mi (1.6 km). The associated ZOI (area ensonified by noise greater than 160 dB) is 8.3 km\2\ (3.1 mi\2\).
Illingworth and Rodkin (2014) measured noise levels during VSP operations associated with post-drilling operations at the Cosmopolitan #A-1 site in lower Cook Inlet during July 2013. The results indicated that the 720 cubic inch airgun array used during the operation produced noise levels exceeding 160 dB re 1 muPa out to a distance of approximately 8,100 ft (2,470 m). Based on these results, the associated ZOI would be 19.17 km\2\ (7.4 mi\2\). See Table 4.
Table 4--Zones of Influence for Proposed Activities
hammering VSP Airguns
ZOI (km\2\)........................... 8.3 19.17
Marine Mammal Densities
Density estimates were derived for Cook Inlet marine mammals other than belugas as described above. An average density was derived for each species based on NMFS aerial survey data from 2005-2014.
For belugas, the ensonified area associated with each activity was overlaid on a map of the density cells derived in Goetz et al. (2012), the cells falling within each ensonified area were quantified, and average cell density calculated. Figure 6-1 in BlueCrest's application shows the associated ensonified areas and beluga density contours relative to the rig tow beginning from Port Graham, while Figure 6-2 shows the same but assumes the rig tow to the well site will begin in upper Cook Inlet. The quantified results are found in Table 5 below, and show that throughout the proposed activity areas the beluga densities are very low.
Table 5--Mean Raw Densities of Beluga Whales With Activity Action Areas Based on the Goetz et al. (2012) Cook
Inlet Beluga Whale Distribution Modeling
Activity Number of cells Mean density Density range
Pipe Driving......................... 8 0.000344 0.000200-0.000562
VSP.................................. 19 0.000346 0.000136-0.000755
This data was then multiplied by the area ensonified in one day, then multiplied by the number of expected days of each type of operation.
Proposed Take Estimates
As noted previously in this document, the potential number of animals that might be exposed to receive continuous SPLs of >=120 dB re 1 muPa (rms) and pulsed SPLs of >=160 dB re 1 muPa (rms) was calculated by multiplying:
The expected species density;
the anticipated area to be ensonified (zone of influence ZOI); and
the estimated total duration of each of the activities expressed in days (24 hrs).
To derive at an estimated total duration for each of the activities the following assumptions were made:
The maximum total duration of impact hammering during drive pipe driving would be 3 days (however, the hammer would not be used continuously over that time period).
The total duration of the VSP data acquisition runs is estimated to be up to 2 days (however, the airguns would not be used continuously over that time period).
Using all of these assumptions, Table 6 outlines the total number of Level B harassment exposures for each species from each of the four activities using the
calculation and assumptions described here.
Table 6--Potential Number of Exposures to Level B Harassment Thresholds During BlueCrest's Proposed Drilling
Program During the 2016 Open Water Season
Species Pipe driving VSP Total
Beluga whale.................................................... 0.1 0.1 0.2