Small Takes of Marine Mammals Incidental to Specified Activities: Marine Geophysical Survey in the Gulf of Alaska (September 2008)
Federal Register: September 12, 2008 (Volume 73, Number 178)
Notices
Page 52950-52959
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DOCID:fr12se08-36
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
RIN 0648-XI15
Small Takes of Marine Mammals Incidental to Specified Activities;
Marine Geophysical Survey in the Gulf of Alaska, September 2008
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; issuance of incidental take authorization.
SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA) regulations, notification is hereby given that NMFS has issued an
Incidental Harassment Authorization (IHA) to Lamont-Doherty Earth
Observatory (L-DEO), a part of Columbia University, for the take of marine mammals, by Level B harassment only, incidental to conducting a marine seismic survey in the Gulf of Alaska during September, 2008.
DATES: Effective September 10, 2008, through October 31, 2008.
ADDRESSES: A copy of the IHA and the application are available by writing to P. Michael Payne, Chief, Permits, Conservation and Education
Division, Office of Protected Resources, National Marine Fisheries
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225 or by telephoning the contact listed here. A copy of the application containing a list of the references used in this document may be obtained by writing to the address specified above, telephoning the contact listed below (see FOR FURTHER INFORMATION CONTACT), or visiting the internet at: http://www.nmfs.noaa.gov/pr/permits/ incidental.htm#applications. Documents cited in this notice may be viewed, by appointment, during regular business hours, at the aforementioned address.
FOR FURTHER INFORMATION CONTACT: Howard Goldstein or Ken Hollingshead,
Office of Protected Resources, NMFS, (301) 713-2289.
SUPPLEMENTARY INFORMATION:
Background
Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking of 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 shall be granted if NMFS finds that the taking will have a negligible impact on the species or stock(s), will not have an unmitigable adverse impact on the availability of the species or stock(s) for subsistence uses (where relevant), and if the permissible methods of taking and requirements pertaining to the mitigation, monitoring and reporting of such takings are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``* * * an impact resulting from the specified activity that cannot be reasonably expected to, and is not reasonably likely to, adversely affect the species or stock through effects on annual rates of recruitment or survival.''
Section 101(a)(5)(D) of the MMPA established an expedited process by which citizens of the United States can apply for an authorization to incidentally take small numbers of marine mammals by 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
.
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of an application followed by a 30-day public notice and comment period on any proposed authorizations for the incidental harassment of marine mammals. Within 45 days of the close of the comment period, NMFS must either approve or deny the authorization.
Summary of Request
On April 10, 2008, NMFS received an application from L-DEO for the taking, by Level B harassment only, of small numbers of 20 species of marine mammals incidental to conducting, under a cooperative agreement with the National Science Foundation (NSF), a marine seismic survey in the Gulf of Alaska during September, 2008. The purpose of the research program was outlined in NMFS' notice of the proposed IHA (73 FR 45407,
August 5, 2008).
Description of the Activity
The seismic survey will involve one source vessel, the R/V Marcus
G. Langseth (Langseth), which will occur offshore from the Saint Elias
Mountains. The Langseth will deploy an array of 36 airguns (6,600 in\3\) as an energy source and, at times, a receiving system consisting of a 8-km (5-mi) towed hydrophone streamer and/or Ocean Bottom
Seismometers (OBSs). The streamer will be towed at a depth of 7 m (23 ft). The OBSs are housed in 43-cm diameter glass spheres that have a gross weight of approximately 45 kg (99 lbs). As the airgun array is towed along the survey lines, the hydrophone streamer and/or OBSs will receive the returning acoustic signals and transfer the data to the on- board processing system.
The Langseth is expected to depart Astoria, Oregon on approximately
September 10, 2008 for the study area in the GOA (see Figure 1 of L-
DEO's application). The airgun array is expected to operate for a total of ~200-250 hours. With OBS deployment and retrieval, the length of the survey will be ~18 days. The overall area within which the STEEP survey will take place is located at ~58-60.5[deg] N, 138-146[deg] W (see
Figure 1 of L-DEO's application). The proposed survey will be conducted in water depths from 3,000 m (9,840 ft) entirely within the territorial waters and Exclusive Economic Zone (EEZ) of the
United States. The exact dates of the activities depend upon logistics, as well as weather conditions and/or the need to repeat some lines if data quality is substandard.
The primary marine seismic survey will consist of two long transect lines that will cross each other (Figure 1 of L-DEO's application). For the longer line paralleling the shoreline, a seismic reflection- refraction profile will be shot using the hydrophone streamer as well as 25 OBSs deployed on the seafloor and 60 Texan seismometers deployed on land across the toe of the Bering Glacier. A reflection-refraction profile will also be obtained from the slightly shorter line that is perpendicular to the shoreline using the hydrophone streamer as well as 17 OBSs; this line will be shot twice if time allows. Both of these lines will have a shot spacing
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of 50 m (164 ft, 20 seconds); if the onshore-offshore line is shot twice, the shot interval used during the second run will be 150 m (492 ft, 60 s). During the reflection-refraction profiling, the airgun array will be towed at a depth of 9 m. In addition, two reflection-only 2- dimensional (2-D) seismic grids will be shot; the western grid is located approximately 150 km (93 mi) from shore whereas the eastern grid is located nearshore (see Figure 1 in L-DEO's application). The shot spacing for these grids will be 50 m (164 ft) and the airgun array will be towed at a depth of 9 m. No OBSs will be deployed during reflection-only profiling. There will be additional operations associated with equipment testing, startup, line changes, and repeat coverage of any areas where initial data quality is sub-standard. In L-
DEO's calculations, 25 percent has been added to the line total for those additional operations.
The planned seismic survey (excluding the 25 percent contingency) will consist of 1,909 km of survey lines including turns (see Figure 1 in L-DEO's application). Most of this effort (923 km or 574 mi) will take place in intermediate water depths of 100-1,000 m and in water depths >1,000 m deep (812 km or 504 mi), and a smaller portion (174 km or 108 mi) will take place in water 1,000 m; 3,280 ft) water during the STEEP survey in the Gulf of Alaska.
Comments and Responses
A notice of receipt of the L-DEO application and proposed IHA was published in the Federal Register on August 5, 2008 ( 73 FR 45407).
During the comment period, NMFS received comments from the Marine
Mammal Commission (Commission). NMFS also received one comment from a private citizen. Following are the comments from the Commission, a private citizen, the Center for Regulatory Effectiveness (CRE), and
NMFS' responses.
Comment 1: The Commission recommends that NMFS provide additional justification for its proposed determination that the planned monitoring program will be sufficient to detect, with reasonable confidence, all marine mammals within or entering the identified safety zones; as such monitoring is essential for determining whether animals are being taken in unanticipated ways and unexpected numbers.
Response: NMFS believes that the planned monitoring program will be sufficient to detect (using visual detection and PAM), with reasonable certainty, most marine mammals within or entering identified safety zones. This monitoring, along with the required mitigation measures
(see below), will result in the least practicable adverse impact on the affected species or stocks and will result in a negligible impact on the affected species or stocks.
The Langseth is utilizing a team of trained marine mammal observers
(MMOs) to both visually monitor from the high observation tower of the
Langseth and to conduct passive acoustic monitoring (PAM). However, there are limitations on marine mammal detection, and ramp-ups are required as a mitigation measure due to these limitations. This monitoring, along with the required mitigation measures (see below), will result in the least practicable adverse impact on the affected species or stocks and will result
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in a negligible impact on the affected species or stocks.
When stationed on the observation platform of the Langseth, the eye level will be approximately 17.8 m (58.4 ft) above sea level, so the visible distance (in good weather) to the horizon is 8.9 nm (16.5 km; the largest safety radii is 2.4 nm, 4.4 km). Big eyes are most effective at scanning the horizon (for blows), while 7 x 50 reticle binoculars are more effective closer in (MMOs also use a naked eye scan). Night vision devices (NVDs) will be used in low light situations. Additionally, MMOs will have a good view in all directions around the entire vessel. Also, nearly 90 percent of the survey transect lines are in intermediate or deep water depths, where the safety radii are all less than 1 nm (1.9 km).
Theoretical detection distance of this PAM system is tens of kilometers. The PAM is operated both during the day and at night.
Though it depends on the lights on the ship, the sea state, and thermal factors, MMOs estimated that visual detection is effective out to between 150 and 250 m (492 and 820 ft) using NVDs and about 30 m (98.4 ft) with the naked eye. However, the PAM operates equally as effectively at night as during the day, especially for sperm whales and dolphins.
The PAM has reliable detection rates out to 3 km (1.6 nm) and more limited ability out to 10s of km. The largest 180-dB safety radii (3.7 km, 2 nm), which is the radii within which the Langseth is required to shut down if a marine mammal enters, are found when the 36-gun array is operating in shallow water at a 9 m (29.5 ft) tow depth. Only 174 km (9 percent) of the total 1,909 km survey lines of the planned seismic survey (excluding 25 percent contingency) will take place in water less than 100 m deep (shallow water). The species most likely to be encountered in the waters of the Gulf of Alaska are Dall's porpoise and
Pacific white-sided dolphins, which have relatively larger group sizes
(2-20 animals for Dall's porpoises but even higher in some areas of the survey, 10-100 or more animals per group for Pacific white-sided dolphins), are not cryptic at the surface, and have relatively short dive times (6 minutes for dolphins), all which generally make them easier to visually detect. Other species that are likely to be encountered during the seismic survey include humpback, fin, and killer whales, have relatively long dive times; however, they are not cryptic at the surface, have large blows and distinct physical features, all which generally make them easier to visually detect. Furthermore, the vocalizations of most of these species are easily detected by the PAM.
During the Maurice Ewing cruise in the GOM in 2003, MMOs detected marine mammals at a distance of approximately 10 km (5.4 nm) from the vessel and identified them to species level at approximately 5 km (2.7 nm) from the vessel, though the bridge of that vessel was only 11 m (36 ft) above the water (vs. the Langseth, which is more than 17 m (55.8 ft) above sea level). All of the 180-dB safety radii for other water depths and tow depths and for the single 40 in\3\ airgun to be used during ramp-ups and power-downs (see below) are less than 2 km (1.1 nm).
The likelihood of visual detection at night is significantly lower than during the day, though the PAM remains just as effective at night as during the day. However, the Langseth will not be starting up the airguns unless the safety range is visible for the entire 30 minutes prior (i.e., not an night), and therefore in all cases at night, the airguns will already be operating, which NMFS believes will cause many cetaceans to avoid the vessel, which therefore will reduce the number likely to come within the safety radii. Additionally, all of the safety radii in intermediate and deep water depths are smaller than 3 km (1.6 nm) and fall easily within the reliable detection capabilities of the
PAM.
Comment 2: The Commission recommends that observations be made during ramp-up procedures to gather data on its effectiveness as a mitigation measure.
Response: The IHA requires that MMOs on the Langseth make observations for 30 minutes prior to ramp-up, during all ramp-ups, and during all daytime seismic operations and record the following information when a marine mammal is sighted:
(I) Species, group size, age/size/sex categories (if determinable), behavior when first sighted and after initial sighting, heading (if consistent), bearing and distance from seismic vessel, sighting cue, apparent reaction to the airguns or vessel (e.g., none, avoidance, approach, paralleling, etc., and including responses to ramp-up), and behavioral pace; and
(ii) Time, location, heading, speed, activity of the vessel
(including number of airguns operations and whether in state of ramp-up or power-down), sea state, visibility, cloud cover, and sun glare.
These requirements should provide information regarding the effectiveness of ramp-up as a mitigation measure, provided animals are detected during ramp-up.
Comment 3: The Commission recommends that the monitoring period prior to the initiation of seismic activities and to the resumption of airgun activities after a power-down be extended to one hour.
Response: As the Commission points out, several species of deep- diving cetaceans are capable of remaining underwater for more than 30 minutes. However, for the following reasons, NMFS believes that 30 minutes is an adequate length for the monitoring period prior to the start-up of airguns: (1) because the Langseth is required to ramp-up, the time monitoring prior to start-up of any but the smallest array is effectively longer than 30 minutes (i.e., ramp-up will begin with the smallest gun in the array and airguns will be added in a sequence such that the source level of the array will increase in steps not exceeding approximately 6 dB per 5-min period over a total duration of 20-40 min); (2) in many cases MMOs are making observations during times when sonar is not being operated and will actually be observing the area prior to the 30-min observation period anyway; (3) many of the species that may be exposed do not stay underwater more than 30 min; and (4) all else being equal and if a deep diving individual happened to be in the area in the short time immediately prior to the pre-start-up monitoring, if an animal's maximum underwater time is 45 minutes, there is only a 1 in 3 chance that its last random surfacing would be prior to the beginning of the required 30 min- monitoring period.
Comment 4: A member of the public opposes the issuance of permits to allow killing of marine mammals.
Response: NMFS does not believe that the authorized activities will result in the death of any marine mammals, nor does this IHA authorize any marine mammal mortality.
Comment 5: CRE states that there is no accompanying Environmental
Impact Statement (EIS) for the GOA IHA, instead, there is only an EA.
CRE asks NMFS if there is any continuing plan to prepare an EIS for the
Langseth.
Response: A Draft Programmatic EIS (Draft PEIS) is being prepared by NSF (not NMFS) for future seismic surveys on the Langseth. However,
NMFS is a cooperating agency under NEPA in its preparation. It is NMFS' intention that the Draft PEIS currently being developed will be used to support, in whole, or in part, future MMPA actions relating to academic research on seismic surveys.
Comment 6: CRE asks NMFS if there is any continuing plan to use the
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Acoustic Integration Model (AIM) for the Langseth.
Response: The use of AIM remains proposed for NSF's Draft PEIS to address potential impacts related to marine seismic research.
Preparation of that EIS continues, and public comments will be solicited when the Draft PEIS is published. AIM was developed by and is proprietary to Marine Acoustics, Inc. The commentor correctly notes that this particular IHA application does not use AIM. This application was prepared for NSF, L-DEO, and NMFS by LGL, Ltd., Environmental
Research Associates (LGL). In the application for the proposed seismic operations, LGL notes that it is using the line transect method to estimate marine mammal exposures and determine exclusion zones, consistent with applications for recent previous NSF-funded research seismic cruises.
Comment 7: CRE requests that be any opportunity for public comment on AIM before NMFS issues AIM for the Langseth or for any other purpose.
Response: The NSF Draft PEIS will make the use of AIM available for public comment. AIM itself will not be available for public comment as it is proprietary.
Comment 8: CRE states that the GOA IHA application and the accompanying EA rely on both visual observers and PAM to monitor compliance with seismic safety radii requirements. Neither the IHA application nor the EA contain a record demonstrating that PAM is accurate and reliable for this purpose. CRE asks NMFS whether there is a record demonstrating PAM is sufficiently accurate and reliable to monitor compliance with seismic safety radii requirements and whether there is an opportunity for public comment on that subject.
Response: It is unclear what the commentor means by the phrase
``monitor compliance with seismic safety radii requirements.'' NMFS believes that visual observers and PAM are effective tools for monitoring marine mammals in the affected area during the seismic survey. PAM is required for monitoring on the Langseth (when practicable), but not for the implementation of mitigation measures.
PAM is used by MMOs and the bioacoustician aboard the Langseth for the detection of vocalizing marine mammals. Any confirmed marine mammal vocalization detections using PAM are communicated to the visual observer(s) on watch to help alert the visual observers to the presence of vocalizing marine mammals in the survey area (not necessarily the safety radii). The use of PAM is therefore used in aid of the visual observers, who monitor the safety radii for presence of marine mammals.
The detection of marine mammals in the vicinity of the array in turn triggers mitigation requirements.
Description of Marine Mammals in the Activity Area
A total of 18 cetacean species, 3 species of pinnipeds, and the northern sea otter are known to or may occur in the GOA study area.
Several of the species that may occur in the project area are listed as
Endangered under the U.S. Endangered Species Act (ESA), including the sperm, humpback, North Pacific right whale, fin, and blue whale and the western stock of Steller sea lions. The eastern stock of Steller sea lions are listed at Threatened. Neither the southcentral and southeast
Alaska population stocks of northern sea otters (Enhydra lutris kenyoni) are listed as Threatened or Endangered under the ESA nor depleted under the MMPA. The northern sea otter is under the jurisdiction of the U.S. Fish and Wildlife Service (USFWS) and therefore is not considered further in this analysis. There is little information on the distribution of marine mammals inhabiting the waters offshore of SE Alaska or the eastern GOA, although a few reports are available (e.g., Buckland et al., 1993; Hobbs and Lerczak, 1993;
Straley et al., 1995; Calambokidis et al., 1997; MacLean and Koski, 2005; Angliss and Outlaw, 2007).
Table 2 outlines the species, their habitat and abundance in the project area, and the estimated exposure levels. Additional information regarding the status and distribution of the marine mammals in the area and how the densities were calculated was included in the notice of the proposed IHA (73 FR 45407, August 5, 2008) and may be found in L-DEO's application.
Number of Indiv.
Percent of Estimated
Species
Habitat
Estimated Population
Avg. Density
Max. Density
Exposed to [gteqt]160 Population Exposed to dB
gteqt160 dB
Odontocetes
Sperm whale (Physeter
Pelagic
24,000 \5\ (Regional) 0.00 \1\
0.00 \1\
49
0.2 macrocephalus)
0.31 \2\
0.58 \2\ 4.04 \3\
6.06 \3\
Cuvier's beaked whale
Pelagic
20,000 \6\ (Regional) 0.00 \1\
0.00 \1\
35
0.2
(Ziphius cavirostris)
2.76 \2\
3.70 \2\ 0.00 \3\
0.00 \3\
Baird's beaked whale
Pelagic
6,000 \7\ (Regional) 0.00 \1\
0.00 \1\
8
0.1
(Berardius bairdii)
0.66 \2\
0.88 \2\ 0.00 \3\
0.00 \3\
Stejneger's beaked whale
Likely Pelagic N.A.
0.00 \1\
0.00 \1\
N.A.
0
(Mesoplodon stejnegeri)
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \0\
Beluga whale (Delphinapterus Coastal & Ice 366 \8\ (Alaska)
0.00 \1\
0.00 \1\
0
N.A. leucas)
Edges
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \3\
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Pacific white-sided dolphin
Pelagic, Shelf, 26,880 \9\ (Alaska,
2.48 \1\
5.41 \1\
56
0.2
(Lagenorhynchus obliquidens) Coastal
Stock)
3.36 \2\
13.83 \2\ 0.00 \3\
0.00 \3\
Killer whale (Orcinus orca)
Pelagic, Shelf, 1,975 \12\ (Alaska)
12.87 \1\
34.14 \1\
116
5.9
Coastal
4.03 \2\
8.81 \2\ 0.00 \3\
0.00 \3\
Harbor Porpoise (Phocoena
Coastal
41,854 \15\ (Alaska, 23.26 \1\
47.27 \1\
346
0.8 phocoena)
Stock)
17.85 \2\
24.21 \2\ 0.00 \3\
0.00 \3\
Dall's Porpoise (Phocoenoides Pelagic & Shelf 83,400 \17\ (Alaska, 146.86 \1\
221.90 \1\
5,379
0.7 dalli)
Stock)
662.63 \2\
877.32 \2\ 141.00 \3\
211.50 \3\
Mysticetes
Humpback whale (Megaptera
Coastal & Banks >6,000 \22\ (Regional) 32.82 \1\
54.58 \1\
246
4.1 novaeangliae)
11.89 \2\
24.37 \2\ 15.60 \3\
15.60 \3\
Minke whale (Balaenoptera
Coastal & Shelf 9,000 \23\ (Regional) 1.20 \1\
4.87 \1\
9
0.1 acutorostrata)
0.24 \2\
1.23 \2\ 0.00 \3\
0.00 \3\
Gray whale (Eschrichtius
Coastal
18,813 \20\ (Regional, 0.00 \1\
0.00 \1\
0
0 robustus)
Stock)
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \3\
Fin whale (Balaenoptera
Pelagic
13,620-18,680 \22\
7.31 \1\
19.40 \1\
89
0.7 physalus)
(Regional)
11.08 \2\
20.25 \2\
............... 0.00 \3\
Blue whale (Balaenoptera
Pelagic, Shelf, 1,744 \11\ (Region)
0.00 \1\
0.00 \1\
0
0 musculus)
Coastal
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \3\
North Pacific right whale
Coastal & Shelf 100-200 \19\
0.00 \1\
0.00 \1\
0
0
(Eubalaena japonica)
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \3\
Pinnipeds
Northern fur seal
Pelagic, Breeds 721,935 \25\
0.00 \1\
0.00 \1\
0
0
(Callorhinus ursinus)
Coastally
(Regional, Stock)
0.00 \2\
0.00 \2\ 0.00 \3\
0.00 \3\
Steller sea lion (Eumetopias Coastal
47,885 \26\ (E. Stock) 3.99 \1\
5.99 \1\
74 (62 E, 12 W)
0.1 E jubatus)
44,780 \27\ (W. Stock) 4.20 \2\
6.30 \2\
0.02 W 0.00 \3\
0.00 \3\
Harbor seal (Phoca vitulina
Coastal
108,670 (Stock)
2.00 \1\
3.00 \1\
269
0.2 richardsi)
20.28 \2\
30.42 \2\ 0.00 \3\
0.00 \3\
Table 2. The habitat, abundance, and conservation status of marine mammals inhabiting the proposed study area in the Gulf of Alaska. Regional abundance estimates are also given, usually for the Northeastern Pacific Ocean or the U.S. West Coast. Note: N.A. = Not available or not applicable.
\1\ Depths 1,000 m (3,300 ft)
\4\ Western GOA and eastern Aleutians (Zerbini et al., 2004).
\5\ Eastern temperate North pacific (Whitehead, 2002).
\6\ Eastern Tropical Pacific (Wade and Gerrodette, 1993).
\7\ Western North Pacific (Reeves and Leatherwood, 1994; Kasuya, 2002).
\8\ Cook Inlet stock (Rugh et al., 2005a).
\9\ GOA (Angliss and Outlaw, 2007).
\10\ North Pacific Ocean (Buckland et al., 1993).
\11\ California/Oregon/Washington (Carretta et al. 2007).
\12\ Minimum abundance in Alaskan waters, includes 1,339 resident and 636 transient (Angliss and Outlaw, 2007).
\13\ Eastern Tropical Pacific (Ford, 2002).
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\14\ SE Alaska stock (Angliss and Outlaw, 2007).
\15\ GOA stock (Angliss and Outlaw 2007).
\16\ Western North Pacific Ocean (totals from Carretta et al., 2007 and Angliss and Outlaw, 2007).
\17\ Alaska stock (Angliss and Outlaw, 2007).
\18\ North Pacific Ocean and Bering Sea (Houk and Jefferson, 1999).
\19\ Eastern North Pacific (Wada, 1973).
\20\ Mean of 2000-2001 and 2001-2002 abundance estimates for eastern North Pacific (Angliss and Outlaw, 2007).
\21\ Western GOA and eastern Aleutians (Zerbini et al., 2006).
\22\ North Pacific Ocean (Carretta et al., 2007).
\23\ North Pacific Ocean (Wada, 1976).
\24\ Central waters of western Alaska and eastern and central Aleutian Islands (Angliss and Outlaw, 2007).
\25\ Abundance for Eastern Pacific Stock (Angliss and Outlaw, 2007).
\26\ Eastern U.S. Stock (Angliss and Outlaw, 2007).
\27\ Western U.S. Stock (Angliss and Outlaw, 2007).
\28\ Alaska statewide (Angliss and Outlaw, 2007).
\29\ Abundance estimate for SE Alaska stock (USFWS 2002 in Angliss and Outlaw, 2007).
\30\ Abundance estimate Southcentral Alaska (USFWS 2002 in Angliss and Outlaw, 2007).
\31\ SW Alaska stock (USFWS 2002 in Angliss and Outlaw, 2007).
Potential Effects on Marine Mammals
The effects of sounds from airguns might include one or more of the following: tolerance, masking of natural sounds, behavioral disturbances, and at least in theory, temporary or permanent hearing impairment, or non-auditory physical or physiological effects
(Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 2007;
Southall et al., 2007). Permanent hearing impairment, in the unlikely event that it occurred, would constitute injury, but temporary threshold shift (TTS) is not an injury (Southall et al., 2007). With the possible exception of some cases of TTS in harbor seals, it is unlikely that the project would result in any cases of temporary impairment, or any significant non-auditory physical or physiological effects. Some behavioral disturbance is expected, but this would be localized and short-term. Also, behavioral disturbance is expected to be limited to relatively short distances.
The notice of the proposed IHA (73 FR 45407, August 5, 2008) included a discussion of the effects of sounds from airguns on mysticetes, odontocetes, and pinnipeds, including tolerance, masking, behavioral disturbance, hearing impairment, and other non-auditory physical effects. Additional information on the behavioral reactions
(or lack thereof) by all types of marine mammals to seismic vessels can be found in Appendix B of L-DEO's application.
The notice of the proposed IHA also included a discussion of the potential effects of the multibeam echosounder (MBES) and the sub- bottom profiler (SBP). Because of the shape of the beams of these sources and their power, NMFS believes it unlikely that marine mammals will be exposed to either the MBES or the SBP at levels at or above those likely to cause harassment. Further, NMFS believes that the brief exposure of cetaceans or pinnipeds to few signals from the multi-beam bathymetric sonar system is not likely to result in the harassment of marine mammals.
Estimated Take by Incidental Harassment
The notice of the proposed IHA (73 FR 45407, August 5, 2008) included an in-depth discussion of the methods used to calculate the densities of the marine mammals in the area of the seismic survey and the take estimates. Additional information was included in L-DEO's application. A summary is included here.
All anticipated ``takes by harassment'' authorized by this IHA are
Level B harassment only, involving temporary changes in behavior. The mitigation measures are expected to minimize the possibility of injurious takes. Take calculations were based on maximum exposure estimates (based on maximum density estimates) vs. best estimates and are based on the 160-dB isopleth of a larger array of airguns. Given these considerations, the predicted number of marine mammals that might be exposed to sounds 160 dB may be somewhat overestimated.
There are few systematic data on the numbers and distributions of marine mammals in SE Alaska and the GOA. Zerbini et al. (2003, 2006, 2007) conducted vessel-based surveys in the northern and western GOA from the Kenai Peninsula to the central Aleutian Islands during July-
August 2001-2003. Killer whales were the principal target of the surveys, but the abundance and distribution of fin, humpback, and minke whales were also reported. Waite (2003) conducted vessel-based surveys in the northern and western GOA from Prince William Sound (PWS) to approximately 160[deg] W off Alaska Peninsula during 26 June- 15 July 2003; cetaceans recorded included small odontocetes, beaked whales, and mysticetes. The eastern part of Zerbini et al. surveys and Waite's survey were confined to water 1,000 m) during non-seismic periods.
Most surveys for pinnipeds in Alaskan waters have estimated the number of animals at haul-out sites, not in the water (e.g., Loughlin, 1994; Sease et al., 2001; Withrow and Cesarone, 2002; Sease and York, 2003). To our knowledge, the estimates of MacLean and Koski (2005) are the only in-water estimates of pinnipeds in the proposed survey area.
The L-DEO survey will occur from September- October, 2008 in the
Gulf of Alaska, , a location and time of year in which the species densities are likely similar or slightly different from those during the above-mentioned surveys in the Gulf of Alaska, but these surveys are the best available data at this time.
Eight species of odontocete whales, five species of mysticete whale, and three species of pinnipeds are expected to be harassed during the seismic survey. Risso's dolphins and short-finned pilot whales are unlikely to occur in the study area and any sightings would be considered extralimital to their range. No take was authorized for either of these species. Stejneger's beaked whales, beluga whales, gray whales, and northern fur seals occur in the Gulf of Alaska, but generally occur in the study area in low numbers or at different times of the year. Although not expected in the area,
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small numbers of take of Stejneger's beaked whales, gray whales, blue whales, and northern fur seals were authorized due to a lack of marine mammal survey data and uncertainty in the study area. No take of North
Pacific right or beluga whales is expected or authorized due to their rare occurrence in the area and the special mitigation for these species of concern. Where stock size wasn't available, NMFS used the estimated abundance in Alaska or the region to determine the percentage of the population exposed to sound levels greater than or equal to 160 dB. Since the take estimates authorized in this IHA are no more than 5.9 percent of any affected cetacean species and no more than 0.2 percent of any affected pinnipeds species found along or offshore of the Alaskan coast, NMFS believes that the estimated take numbers for these species and stocks are small relative to the relevant population of these affected species or stocks.
Table 3 (see below) outlines the species, estimated stock population (minimum and best), and estimated percentage of the stock exposed to seismic impulses in the project area. Additional information regarding the status, abundance, and distribution of the marine mammals in the area and how the densities were calculated was included in Table 2 (see above), the notice of the proposed IHA (73 FR 45407, August 5, 2008) and may be found in L-DEO's application
Potential Effects on Habitat
A detailed discussion of the potential effects of this action on marine mammal habitat, including physiological and behavioral effects on marine fish and invertebrates, was included in the notice of the proposed IHA (73 FR 45407, August 5, 2008). Based on the discussion in the proposed IHA notice and the nature of the activities (limited duration), the authorized operations are not expected to have any habitat-related effects that could cause significant or long-term consequences for individual marine mammals or their populations or stocks. Similarly, any effects to food sources are expected to be negligible.
Subsistence Activities
The proposed project could potentially impact the availability of marine mammals for subsistence harvest in a very small area immediately around the Langseth, and for a very short time period during seismic activities. Considering the limited time and locations for the planned seismic surveys, most of which are well offshore, the proposed project is not expected to have any significant impacts to the availability of beluga whales, Steller sea lions, Pacific harbor seals, and sea otters.
Also, seismic surveys can at times, cause changes in the catchability of fish.
To avoid having an unmitigable adverse impact on subsistence uses of marine mammals, NMFS is required to implement mitigation measures to ensure that NSF and L-DEO's seismic activities do not have an unmitigable adverse impact on subsistence uses of marine mammals in the project area. L-DEO will minimize the potential to negatively impact the subsistence harvest by coordinating with local native communities and avoiding areas (to the maximum extent practicable) where subsistence collectors are hunting marine mammals and fishing.
Additionally, L-DEO will consult with each village near the planned project area to identify and avoid areas of potential conflict. These consultations will include all marine subsistence activities (mammals and fisheries). Implementation of these measures ensures that there will not be significant social or economic impacts on the coastal inhabitants of the GOA and Southeast Alaska. NMFS has determined (based on the above stated reasons) that L-DEO's activities will not have an unmitigable adverse impact on the subsistence uses of the species hunted by Alaska Natives and a requirement to these effects will be addressed in the IHA.
Monitoring and Mitigation
Mitigation and monitoring measures required to be implemented for the proposed seismic survey have been developed and refined during previous L-DEO seismic survey studies and associated environmental assessments (EAs), IHA applications, and IHAs. The mitigation and monitoring measures described herein represent a combination of the procedures required by past IHAs for other similar projects and on recommended best practices in Richardson et al. (1995), Pierson et al.
(1998), and Weir and Dolman (2007). The measures are described in detail below.
Required mitigation measures include: (1) speed or course alteration, provided that doing so will not compromise operational safety requirements; (2) power-down procedures; (3) shutdown procedures; (4) ramp-up procedures; (5) special procedures for situations and species of particular concern, e.g., avoidance of critical habitat around Steller sea lion rookeries and haul-outs (see
``shut-down procedures'' and ``special procedures for situations and species of particular concern,'' below).
Vessel-based Visual Monitoring
Vessel-based marine mammal visual observers (MMVOs) will be based aboard the seismic source vessel and will watch for marine mammals near the vessel during daytime airgun operations and during start-ups of airguns at night. MMVOs will also watch for marine mammals near the seismic vessel for at least 30 minutes prior to the start of airgun operations and after an extended shutdown of the airguns (i.e., 7 minutes). When feasible, MMVOs will also make observations during daytime periods when the seismic system is not operating for comparison of animal abundance and behavior. Based on MMVO observations, airguns will be powered down, or if necessary, shut down completely (see below), when marine mammals are detected within or about to enter a designated safety radius corresponding to 180 dB (for cetaceans) and 190 dB (for pinnipeds) isopleths. The MMVOs will continue to maintain watch to determine when the animal(s) are outside the safety radius, and airgun operations will not resume until the animal has left that zone. The predicted distances for the safety radius' are listed according to the sound source, water depth, and received isopleth in
Table 1.
During seismic operations in the Gulf of Alaska, at least three visual observers and one bioacoustician will be based aboard the
Langseth. MMVOs will be appointed by L-DEO with NMFS concurrence. At least one MMVO, and when practical two, will monitor the safety radii for marine mammals during daytime operations and nighttime startups of the airguns. Use of two simultaneous MMVOs will increase the proportion of the animals present near the source vessel that are detected.
MMVO(s) will be on duty in shifts of duration no longer than 4 hours.
The vessel crew will also be instructed to assist in detecting marine mammals and implementing mitigation requirements (if practical). Before the start of the seismic survey the crew will be given additional instruction regarding how to do so.
The Langseth is a suitable platform for marine mammal observations.
When stationed on the observation platform, the eye level will be approximately 17.8 m (58.4 ft) above sea level, and the observer will have a good view around the entire vessel. During daytime, the MMVO(s) will scan the area around the vessel systematically with reticle binoculars (e.g., 7x50 Fujinon), Big-eye binoculars (25x150), and with the naked eye. During darkness, NVDs will be
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available (ITT F500 Series Generation 3 binocular-image intensifier or equivalent). Laser rangefinding binoculars (Leica LRF 1200 laser rangefinder or equivalent) will be available to assist with distance estimation. Those are useful in training MMVOs to estimate distances visually, but are generally not useful in measuring distances to animals directly.
Passive Acoustic Monitoring
PAM will take place to complement the visual monitoring program.
Acoustic monitoring can be used in addition to visual observations to improve detection, identification, localization, and tracking of cetaceans. It is only useful when marine mammals call, but it can be effective either by day or by night and does not depend on good visibility. The acoustic monitoring will serve to alert visual observers when vocalizing cetaceans are detected. It will be monitored in real time so visual observers can be advised when cetaceans are detected. When bearings (primary and mirror-image) to calling cetacean(s) are determined, the bearings will be relayed to the visual observer to help him/her sight the calling animal(s).
The PAM system consists of hardware (i.e., hydrophones) and software. The ``wet end'' of the system consists of a low-noise, towed hydrophone array that is connected to the vessel by a ``hairy'' faired cable. The array will be deployed from a winch located on the back deck. A deck cable will connect from the winch to the main computer lab where the acoustic station and signal condition and processing system will be located. Th lead-in from the hydrophone array is approximately 400 m (1,312 ft) long, and the active part of the hydrophone is approximately 56 m (184 ft) long. The hydrophone array is typically towed at depths
