[Federal Register Volume 68, Number 144 (Monday, July 28, 2003)]
[Notices]
[Pages 44291-44297]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-19035]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 052803A]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Oceanographic Surveys at the Storegga Slide, Norwegian Sea

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

ACTION:  Notice of receipt of application and proposed incidental take 
authorization; request for comments.

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SUMMARY:  NMFS has received an application from the Lamont-Doherty 
Earth Observatory (LDEO) for an Incidental Harassment Authorization 
(IHA) to take small numbers of marine mammals, by harassment, 
incidental to conducting oceanographic surveys at the Storegga slide 
off the west coast of Norway in the Norwegian Sea. Under the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an authorization to LDEO to incidentally take, by 
harassment, small numbers of several species of cetaceans and pinnipeds 
for a limited period of time within the next year.

DATES:  Comments and information must be received no later than August 
27, 2003.

ADDRESSES:  Comments on the application should be addressed to Chief, 
Marine Mammal Conservation 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 this address or by 
telephoning the contact listed here. Comments cannot be accepted if 
submitted via e-mail or the Internet.

FOR FURTHER INFORMATION CONTACT: Sarah C. Hagedorn, Office of Protected 
Resources, NMFS, (301) 713-2322, ext 117.

SUPPLEMENTARY INFORMATION:

[[Page 44292]]

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.
    Permission may be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s) and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses and that the permissible methods of 
taking and requirements pertaining to the 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.''
    Subsection 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. Under Section 3(18)(A), 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; 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.
    The term ``Level A harassment'' means harassment described in 
subparagraph (A)(i). The term ``Level B harassment'' means harassment 
described in subparagraph (A)(ii).
    Subsection 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 issue or deny issuance of the authorization.

Summary of Request

    On April 21, 2003, NMFS received an application from LDEO for the 
taking, by harassment, of several species of marine mammals incidental 
to conducting a seismic survey program within the Storegga slide area 
off the west coast of Norway, in the Norwegian Sea, between 8[deg]W. 
and 7[deg]E. and between 62 and 68[deg]N. during late August and 
September 2003. The Storegga slide was produced by colossal slope 
failures on the Norwegian continental margin in the late Quarternary 
period. The purpose of this survey is to determine whether submarine 
landslides can release methane from hydrate into the oceans and/or 
atmosphere. More specifically, the survey of the Storegga slide seeks 
to discover: (1) how much hydrate and free gas is present in the 
Storegga region and how it is distributed, (2) if methane escaped from 
the slide, and if so, how much, when and by what mechanisms, and (3) if 
hydrate dissociation promotes and/or localizes submarine landslides. A 
coordinated seismic and coring study of the Storegga slide is proposed 
to obtain information on these subjects (the coring portion of the 
project will be completed in 2004). This study will help explain 
whether methane in gas hydrate reservoirs is mobile and can affect the 
earth's climate.

Description of the Activity

    The seismic survey will involve a single vessel, the R/V Maurice 
Ewing, which will conduct the seismic work. The Maurice Ewing will 
deploy an array of airguns as an energy source, plus a 6-km (3.2-nm) 
towed streamer containing hydrophones to receive the returning acoustic 
signals.
    All planned geophysical data acquisition activities will be 
conducted by LDEO scientists, with the participation of scientists from 
the University of Wyoming. Water depths within the Storegga slide 
survey area will range from approximately 100 to 5,000 m (330 to 16,405 
ft). The Maurice Ewing will initially deploy a 2-GI gun array for 
several survey lines, and then a 6-airgun array will be employed for 
several survey lines. Whichever array produces better data will be used 
for the rest of the cruise. The project will consist of 3,109 km (1,678 
n.mi) of survey lines, of which approximately 2,596 km (1,402 n.mi) 
will be conducted in water depths greater than 1,000 m(3,280 ft.), 504 
km (272 n.mi) will be surveyed in depths 100-1000 m (330-3,280 ft.), 
and 9 km (4.9 n.mi) will be surveyed in water less than 100 m (330 ft.) 
deep. 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.
    The procedures to be used for the 2003 seismic survey will be 
similar to those used during previous seismic surveys by LDEO, e.g., in 
the equatorial Pacific Ocean (Carbotte et al., 1998, 2000). The 
proposed program will use conventional seismic methodology with a towed 
airgun array as the energy source and a towed streamer containing 
hydrophones as the receiver system. The energy to the airgun array is 
compressed air supplied by compressors on board the source vessel. In 
addition, a multi-beam bathymetric sonar will be operated from the 
source vessel continuously throughout the entire cruise, and a lower-
energy sub-bottom profiler will also be operated during most of the 
survey. Seismic surveys will likely commence on August 28, 2003, and 
continue until September 25, 2003, for a total of 29 days of seismic 
surveying.
    The R/V Maurice Ewing will be used as the source vessel. It will 
tow the airgun array (either the 2-GI gun or 6-gun array) and a 
streamer containing hydrophones along predetermined lines. The vessel 
will travel at 4-5 knots (7.4-9.3 km/hr), and seismic pulses will be 
emitted at intervals of approximately 20 seconds. The 20-sec spacing 
corresponds to a shot interval of about 50 m (164 ft). The 6-gun array 
will include six 2000 psi 1500C Bolt airguns ranging in chamber volume 
from 80 to 500 in\3\, with a total volume of 1,350 in3. These airguns 
will be spaced in an approximate rectangle with dimensions 12 m (39.4 
ft)(across track) by 10 m (32.8 ft)(along track). The two 105 in3 GI 
guns will be towed 7.8 m (25.6 ft) apart side by side and 37 m (121.4 
ft) behind the vessel, with a total volume of 210 in\3\.
    The dominant frequency components for both airgun arrays is 0-188 
Hz. The 2-airgun array will have a peak sound source level of 237 dB re 
1 microPa or 243 dB peak-to-peak (P-P). The 6-airgun array will have a 
peak sound source level of 243 dB re 1 microPa or 250 dB P-P. These are 
the nominal source levels for the sound directed downward, and 
represent the theoretical source level close to a single point source 
emitting the same sound as that emitted by the array of 2 or 6 sources. 
Because the actual source is a distributed sound source (2 or 6 guns) 
rather than a single point source, the highest sound levels measurable 
at any location in the water will be less than the nominal source 
level. Also, because of the downward directional nature of the sound 
from these airgun arrays, the effective source level for sound 
propagating in near-horizontal directions will be substantially lower.

[[Page 44293]]

    Along with the airgun operations, two additional acoustical data 
acquisition systems will be operated during most or all of the cruise. 
The ocean floor will be mapped with an Atlas Hydrosweep DS-2 multi-beam 
15.5-kHz bathymetric sonar, and a 3.5-kHz sub-bottom profiler will also 
be operated along with the multi-beam sonar. These mid-frequency sound 
sources are commonly operated from the Maurice Ewing simultaneous with 
the airgun array.
    The Atlas Hydrosweep is mounted in the hull of the R/V Maurice 
Ewing, and it operates in three modes, depending on the water depth. 
The first mode is when water depth is <400 (1312.3 ft). The source 
output is 210 dB re 1 microPa-m rms and a single 1-millisec pulse or 
``ping'' per second is transmitted, with a beamwidth of 2.67 degrees 
fore-aft and 90 degrees in beamwidth. The beamwidth is measured to the 
3 dB point, as is usually quoted for sonars. The other two modes are 
deep-water modes: The Omni mode is identical to the shallow-water mode 
except that the source output is 220 dB rms. The Omni mode is normally 
used only during start up. The Rotational Directional Transmission 
(RDT) mode is normally used during deep-water operation and has a 237 
dB rms source output. In the RDT mode, each ``ping'' consists of five 
successive transmissions, each ensonifying a beam that extends 2.67 
degrees fore-aft and approximately 30 degrees in the cross-track 
direction. The five successive transmissions (segments) sweep from port 
to starboard with minor overlap, spanning an overall cross-track 
angular extent of about 140 degrees, with tiny (<1 millisec) gaps 
between the pulses for successive 30-degree segments. The total 
duration of the ``ping'', including all 5 successive segments, varies 
with water depth but is 1 millisec in water depths <500 m (1640.4 ft) 
and 10 millisec in the deepest water.
    The sub-bottom profiler is normally operated to provide information 
about the sedimentary features and bottom topography that is 
simultaneously being mapped by the Hydrosweep. The energy from the sub-
bottom profiler is directed downward by a 3.5-kHz transducer mounted in 
the hull of the Maurice Ewing. The output varies with water depth from 
50 watts in shallow water to 800 watts in deep water. Sounds from the 
sub-bottom profiler are very short pulses, occurring for 1, 2 or 4 msec 
once every second. Pulse interval is 1 second but a common mode of 
operation is to broadcast five pulses at 1-s intervals followed by a 5-
s pause. Most of the energy in the sound pulses emitted by this multi-
beam sonar is at mid-frequencies, centered at 3.5 kHz. The beamwidth is 
approximately 30[deg] and is directed downward.
    Sound levels have not been measured for the sub-bottom profiler 
used by the Maurice Ewing, but Burgess and Lawson (2000) measured the 
sounds propagating more or less horizontally from a similar unit with 
similar source output (205 dB re 1 microPa-m). The 160 and 180 dB re 1 
microPa (rms) radii, in the horizontal direction, were estimated to be 
near 20 m (66 ft) and 8 m (26 ft), respectively, from the source, as 
measured in 13 m (43 ft) water depth. The corresponding distances for 
an animal in the beam below the transducer would be greater, on the 
order of 180 m (591 ft) and 18 m (59 ft), assuming spherical spreading.
    The sub-bottom profiler on the Maurice Ewing has a maximum source 
level of 204 dB re 1 microPa-m. Thus the received level would be 
expected to decrease to 160 and 180 dB at about 160 m (525 ft) and 16 m 
(52 ft) below the transducer, respectively (assuming spherical 
spreading). Corresponding distances in the horizontal plane would be 
lower, given the directionality of this source (30[deg] beamwidth) and 
the measurements of Burgess and Lawson (2000). Additional information 
on the airgun arrays, Atlas Hydrosweep, and sub-bottom profiler 
specifications is contained in the application, which is available upon 
request (see ADDRESSES).

Description of Habitat and Marine Mammals Affected by the Activity

    A detailed description of the Norwegian Sea and its associated 
marine mammals can be found in a number of documents referenced in the 
LDEO application and is not repeated here. Approximately 24 species of 
cetaceans and seven species of pinnipeds may be found within the area 
of the Storegga slide. These species are the sperm whale (Physeter 
macrocephalus), Cuvier's beaked whale (Ziphius cavirostris), northern 
bottlenose whale (Hyperoodon ampullatus), Sowerby's beaked whale 
(Mesoplodon bidens), Blainville's beaked whale (Mesoplodon 
densirostris), beluga whale (Delphinapterus leucas), narwhal (Monodon 
monoceros), bottlenose dolphin (Tursiops truncatus), striped dolphin 
(Stenella coeruleoalba), short-beaked common dolphin (Delphinus 
delphis), white-beaked dolphin (Lagenorhynchus albirostris), Atlantic 
white-sided dolphin (Lagenorhynchus acutus), Risso's dolphin (Grampus 
griseus), false killer whale (Pseudorca crassidens), killer whale 
(Orcinus orca), long-finned pilot whale (Globicephala melas), harbor 
porpoise (Phocoena phocoena), North Atlantic right whale (Eubalaena 
glacialis), bowhead whale (Balaena mysticetus), humpback whale 
(Megaptera novaeangliae), minke whale (Balaenoptera acutorostrata), sei 
whale (Balaenoptera borealis), fin whale (Balaenoptera physalus), blue 
whale (Balaenoptera musculus), walrus (Odobenus rosmarus), bearded seal 
(Erignathus barbatus), hooded seal (Cystophora cristata), harbor seal 
(Phoca vitulina), ringed seal (Pusa hispida), grey seal (Halichoerus 
grypus), and the harp seal (Pagophilus groenlandicus). Additional 
information on most of these species is contained in Caretta et al. 
(2001, 2002) which is available at: http://www.nmfs.noaa.gov/prot_res/PR2/Stock_Assessment_Program/sars.html.

Potential Effects on Marine Mammals

    With 2-GI gun and 6-gun arrays, the distances at which seismic 
pulses are expected to diminish to received levels of 190, 180, 170 dB 
and 160 dB re 1 microPa, on an rms basis, are as follows:

------------------------------------------------------------------------
                                             RMS Radii (m/ft)
          Airgun Array           ---------------------------------------
                                   190 dB   180 dB    170 dB     160 dB
------------------------------------------------------------------------
2 GI guns.......................    15/49   50/164    155/509   520/1706
6 airguns.......................   50/164  220/722   700/2297  2700/8859
------------------------------------------------------------------------

    An earlier notice of a (LDEO) application and proposed IHA was 
published in the Federal Register on April 14, 2003 (68 FR 17909). That 
notice described, in detail, the characteristics of the Ewing's 
acoustic sources and, in general, the anticipated effects on marine 
mammals including masking, disturbance, and potential

[[Page 44294]]

hearing impairment and other physical effects. That information is not 
repeated here. However, possible effects of the sub-bottom profiler, 
which was not used in the project described in that notice, are 
described below. The LDEO application also provides information on what 
is known about the effects on marine mammals of the types of seismic 
operations planned by LDEO.

Masking by Sub-bottom Profiler Signals

    There is little chance that marine mammal communications will be 
masked appreciably by the sub-bottom profiler signals given its 
relatively low power output, the low duty cycle, directionality, and 
the brief period when an individual mammal is likely to be within its 
beam. Furthermore, in the case of baleen whales, the sonar signals do 
not overlap with the predominant frequencies in the calls, which would 
avoid significant masking.

Behavioral Responses Resulting from Sub-bottom Profiler Signals

    Marine mammal behavioral reactions to pulsed sound sources and 
responses to the sub-bottom profiler are likely to be similar to those 
of other pulsed sources at the same received levels. However, the 
pulsed signals from the sub-bottom profiler are much weaker than those 
from the airgun array and the multi-beam sonar. Therefore behavioral 
responses rising to Level B harassment are not expected unless marine 
mammals are very close to the source, e.g. within about 160 m (525 ft) 
below the vessel, or a lesser distance to the side. Because simple 
momentary behavioral reactions that are within normal behavioral 
patterns for that species are not considered to be a taking, the very 
brief exposure of cetaceans to small numbers of signals from the sub-
bottom profiler is unlikely to result in a ``take'' by harassment.

Hearing Impairment and Other Physical Effects

    Source levels of the sub-bottom profiler are much lower than those 
of the airguns and the multi-beam sonar that will be used during the 
planned project. Furthermore, received levels of pulsed sounds that are 
necessary to cause temporary or permanent hearing impairment in marine 
mammals appear to be higher than 180 dB. Thus, it is unlikely that the 
sub-bottom profiler produces pulse levels strong enough to cause 
hearing impairment or other physical injuries even in an animal that is 
briefly in a position immediately adjacent to the source.
    Furthermore, the sub-bottom profiler is usually operated 
simultaneously with other higher-power acoustic sources. Many marine 
mammals will move away in response to the approaching higher-power 
sources before the mammals would be close enough to be affected by the 
less intense sounds from the sub-bottom profiler. In the event that 
mammals do not avoid the approaching vessel and its various sound 
sources, mitigation measures that would be applied to minimize effects 
of the higher-power sources (discussed later in this document) would 
further reduce or eliminate any minor effects of the sub-bottom 
profiler.

Estimates of Take by Harassment for the Norwegian Sea Cruise

    The estimates of takes by harassment are based on the number of 
marine mammals that might be found within the 160 dB isopleth radius 
and potentially disturbed by operations with the 6-airgun array planned 
for the project. If the 2-GI gun array is used for all or part of the 
survey, the numbers of marine mammals that might be affected by the 
proposed seismic survey would be lower than the estimates described 
below. If only the 2-GI gun array is used, the numbers of animals that 
would encounter airgun sounds [gteqt]160 dB re 1 (rms) would be about 
one-fifth of the number if only the 6-gun array were used.
    Based on summer marine mammal density survey data collected by 
Sigurjonsson and Gunnlaugsson (1989), LDEO used its best estimate of 
density to compute a best estimate of the number of marine mammals that 
may be exposed to seismic sounds [gteqt]160 dB re 1 microPa (rms) 
(NMFS' current criterion for onset of Level B harassment), except for 
bottlenose whales. Northern bottlenose whales are migratory and most 
leave the proposed seismic survey area before the end of June 
(Benjaminsen 1972; Sigurjonsson and Gunnlaugsson 1990). Therefore, only 
a few, if any, bottlenose whales may be seen during the seismic survey 
in the study area during late August to September. For bottlenose 
whales, LDEO used 0.10x the observed average or maximum density to 
calculate the numbers that might be exposed to seismic sounds, but even 
this reduced number is likely a high estimate. For all other species, 
the average densities were multiplied by the proposed survey effort 
(3109 km or 1678 n.mi) and twice the 160-dB safety radius around the 6-
gun array to estimate the ``best estimate'' of the numbers of animals 
that might be exposed to sound levels [gteqt]160 dB re 1 microPa (rms) 
during the proposed seismic survey program.
    Based on this method, Table 3 in LDEO (2003) gives the best 
estimates of densities for each species or species group of marine 
mammal that might be exposed to received levels [gteqt]160 dB re 1 
microPa (rms), and thus potentially taken by Level B harassment, during 
seismic surveys in the proposed study area of the Norwegian Sea. Of 
these, 86 animals would be endangered species, primarily fin (42), 
humpback (22), and sperm whales (18). Delphinidae would account for 75 
percent of the overall estimate for potential taking by harassment, 
with white-beaked dolphins (298) believed to account for about 90 
percent of all delphinids in the area of the proposed seismic survey, 
and with killer whales (137) and long-finned pilot whales (302) 
accounting for most of the remaining 10 percent. However, part or all 
of the survey could be conducted with 2-GI guns. The 160-dB radius for 
the 2-GI gun array is 520 m (1706 ft) or 19 percent of that of the 6-
gun array. Thus, if all surveys were conducted with the 2 GI guns, best 
estimates of the numbers of animals that would be exposed to seismic 
sounds [gteqt]160 dB would be much less.
    As described previously (68 FR 17909), animals subjected to sound 
levels [gteqt]160 dB may alter their behavior or distribution, and 
therefore might be considered to be taken by Level B harassment. 
However, the 160 dB criterion is based on studies of baleen whales. 
Odontocete hearing at low frequencies is relatively insensitive, and 
dolphins and harbor porpoises generally appear to be more tolerant of 
strong sounds than are most baleen whales. Delphinidae have their best 
hearing in the higher frequencies and are unlikely to be as sensitive 
as the mysticete whales to the low frequency of the airgun array. 
Therefore, they are less likely to experience Level B harassment at 160 
dB. A more likely threshold for onset of Level B harassment in response 
to seismic sounds is at about 170 dB.

Conclusions-Effects on Cetaceans

    Strong avoidance reactions by several species of mysticetes to 
seismic vessels have been observed at ranges up to 6 to 8 km (3.2 to 
4.3 nm) and occasionally as far as 20-30 km (10.8-16.2 nm) from the 
source vessel. Some bowhead whales avoided waters within 30 km (16.2 
nm) of the seismic operation. However, reactions at such long distances 
appear to be atypical of other species of mysticetes, and even for 
bowheads may only apply during migration.
    Odontocete reactions to seismic pulses, or at least those of 
dolphins, are expected to extend to lesser distances

[[Page 44295]]

than are those of mysticetes. Odontocete low-frequency hearing is less 
sensitive than that of mysticetes, and dolphins are often seen from 
seismic vessels. In fact, there are documented instances of dolphins 
approaching active seismic vessels. However, dolphins as well as some 
other types of odontocetes sometimes show avoidance responses and/or 
other changes in behavior when near operating seismic vessels.
    Taking account of the mitigation measures that are planned, effects 
on cetaceans are generally expected to be limited to avoidance of the 
area around the seismic operation and short-term changes in behavior, 
falling within the MMPA definition of ``Level B harassment.'' In the 
cases of mysticetes, these reactions are expected to involve small 
numbers of individual cetaceans because few mysticetes occur in the 
area where seismic surveys are proposed. LDEO's best estimate is that 
42 fin whales, or 0.5 percent of the estimated fin whale population in 
and adjacent to the study area, will be exposed to sound levels 
[gteqt]160 dB re 1 microPa (rms) and potentially affected. Similarly, 
22 humpback whales, or 0.8 percent, and 18 sperm whales, or 0.2 percent 
of their populations that occur in and adjacent to the proposed survey 
area, would receive seismic sounds [gteqt]160 dB. Therefore, these 
potential takings by Level B harassment will have a negligible impact 
on their populations. Numbers and impact would be even smaller if the 
2-GI gun array is used for a substantial fraction of the survey 
project.
    Larger numbers of odontocetes may be affected by the proposed 
activities, but the populations sizes of the main species are large and 
the numbers potentially affected are small relative to the population 
sizes. The best estimate of the total number of odontocetes that might 
be exposed to [gteqt]160 dB re 1 microPa (rms) in the proposed survey 
area in the Norwegian Sea is 878. Of these, 770 are Delphinidae, and of 
these about 200 might be exposed to [gteqt]170 dB. These figures are 
<0.1 percent of the populations of these combined species that occur in 
the Northeast Atlantic, and the 200 value is believed to be a more 
accurate estimate of the number potentially affected.
    Mitigation measures such as controlled speed, look-outs, non-
pursuit, ramp-ups, avoidance of start-ups during periods of darkness 
when possible, and shut-down when within defined ranges (See 
Mitigation) should further reduce short-term reactions to disturbance, 
and minimize any effects on hearing sensitivity.

Conclusions-effects on Pinnipeds

    Very few if any pinnipeds are expected to be encountered during the 
proposed seismic survey in the Norwegian Sea. A maximum of 70 pinnipeds 
in the Storegga slide area may be affected by the proposed seismic 
surveys. If pinnipeds are encountered, the proposed seismic activities 
would have, at most, a short-term effect on their behavior and no long-
term impacts on individual seals or their populations. Responses of 
pinnipeds to acoustic disturbance are variable, but usually quite 
limited. Effects are expected to be limited to short-term and localized 
behavioral changes falling within the MMPA definition of Level B 
harassment.

Mitigation

    For the proposed seismic operations in the Storegga slide area in 
2003, LDEO will use 2 GI guns with a total volume of 210 in\3\ and/or a 
6-gun array with a total volume of 1350 in3. The airguns comprising 
these arrays will be spread out horizontally, so that the energy from 
the arrays will be directed mostly downward.
    Modeled results for the 2- and 6-gun arrays indicate received 
levels to the 180-dB re 1 microPa (rms) isopleth (the level for the 
potential for Level A harassment applicable to cetaceans) were 
estimated as 50 and 220 m (164 and 722 ft), respectively. The radii 
around the 2- and 6-gun arrays where the received level would be 190 dB 
re 1 microPa (rms), (the level for the potential for Level A harassment 
applicable to pinnipeds), were estimated as 15 and 50 m (49 and 164 
ft), respectively. Results from a calibration study that occurred in 
late the spring of 2003 in the Gulf of Mexico will determine the actual 
radii corresponding to each sound level. If the modeled radii have not 
been verified by the time of the Storegga slide surveys, LDEO proposes 
to use 1.5 times the 180- (cetaceans) and 190- (pinnipeds) dB radii 
predicted by the model as the safety radii until the radii have been 
verified. Thus, during the Storegga slide cruise the proposed safety 
radii for cetaceans are 75 and 330 m (246 and 1,083 ft), respectively, 
for the 2-GI gun and 6-gun arrays, and the proposed safety radii for 
pinnipeds are 23 and 75 m (75 and 246 ft), respectively.
    Vessel-based observers will monitor marine mammals in the vicinity 
of the arrays. LDEO proposes to shut down the seismic source if marine 
mammals are observed within the proposed safety radii. Also, LDEO 
proposes to use a ramp-up procedure when commencing operations using 
the 6-gun array. Ramp-up will begin with the smallest gun in the array 
(80 in\3\), and guns will be added in a sequence such that the source 
level of the array will increase at a rate no greater than 6 dB per 5-
minute period over a total duration of about 14 minutes. Ramp-up will 
not occur for the 2-GI gun array because the total air discharge volume 
is small (210 in\3\). Please refer to LDEOs application for more 
detailed information about the mitigation measures that are an integral 
part of the planned activity.

Operational Mitigation

    The directional nature of the 6-airgun array to be used in this 
project is an important mitigating factor, resulting in lower sound 
levels at any given horizontal distance than would be expected at that 
distance if the source were omnidirectional with the stated nominal 
source level. Because the actual seismic source is a distributed sound 
source (2 or 6 guns) rather than a single point source, the highest 
sound levels measurable at any location in the water will be less than 
the nominal source level.

Marine Mammal Monitoring

    Up to three vessel-based observers will be stationed on the R/V 
Maurice Ewing during seismic operations in the Storegga slide area. 
Vessel-based observers will monitor for marine mammals near the seismic 
source vessel for at least 30 minutes prior to and during all daylight 
ramp-up and airgun operations, and during any nighttime startups of the 
airguns. Airgun operations will be suspended when marine mammals are 
observed within, or about to enter, designated safety zones, where 
there is a possibility of Level A harassment. Observers will not be on 
duty during ongoing seismic operations at night; bridge personnel will 
watch for marine mammals during this period and will call for the 
airguns to be shut down if marine mammals are observed in or about to 
enter the safety radii. A marine mammal observer will be on ``standby'' 
at night, in case bridge personnel see a marine mammal. An image-
intensifier night-vision device (NVD) will be available for use at 
night, although past experience has shown that NVDs are of limited 
value for this purpose. If the airguns are started up at night, two 
marine mammal observers will monitor for marine mammals near the source 
vessel for 30 minutes prior to start up using night-vision devices. The 
30-minute observation period is only required prior to commencing 
seismic operations following an extended shut down period.

[[Page 44296]]

    The R/V Maurice Ewing is a suitable platform for marine mammal 
observations. The observer's eye level will be approximately 11 m (36 
ft) above sea level when stationed on the bridge (the highest practical 
vantage point on the vessel), allowing for good visibility within a 
210[deg] arc for each observer. The proposed monitoring plan is 
summarized later in this document.

Proposed Safety Radii

    Received sound levels have been modeled for the 2-GI guns and the 
6-airgun arrays. Based on the modeling, estimates of the 190-, 180-, 
170-, and 160-dB re 1 microPa (rms) distances (safety radii) for these 
arrays have been provided previously in this document.
    Airgun operations will be suspended immediately when cetaceans are 
seen within or about to enter the appropriate 180-dB (rms) radius, or 
if pinnipeds are seen within or about to enter the 190-dB (rms) radius. 
These 180- and 190-dB criteria are consistent with guidelines listed 
for cetaceans and pinnipeds by NMFS (2000) and other guidance by NMFS.

Mitigation During Operations

    The following mitigation measures, as well as marine mammal 
monitoring, will be adopted during the proposed Storegga slide seismic 
survey program and the acoustic verification program, provided that 
doing so will not compromise operational safety requirements: (1) 
Course alteration; and (2) Shut-down procedures; and (3) Ramp-up 
procedures.
Course Alteration
    If a marine mammal is detected outside the safety radius and, based 
on its position and the relative motion, is likely to enter the safety 
radius, alternative ship tracks will be plotted against anticipated 
mammal locations. The vessel's direct course and/or speed will be 
changed in a manner that also minimizes the effect to the planned 
science objectives. The marine mammal activities and movements relative 
to the seismic vessel will be closely monitored to ensure that the 
marine mammal does not approach within the safety radius. If the mammal 
appears likely to enter the safey radius, further mitigative actions 
will be taken, i.e., either further course alterations or shutdown of 
the airguns.
Shutdown Procedures
    Vessel-based observers will monitor marine mammals near the seismic 
vessel during daylight and for at least 30 minutes prior to start up 
during darkness throughout the program. Airgun operations will be 
suspended immediately when marine mammals are observed within, or about 
to enter, designated safety zones. The shutdown procedure should be 
accomplished within several seconds or one shot period of the 
determination that a marine mammal is within or about to enter the 
safety zone. Airgun operations will not resume until the marine mammal 
is outside the safety radius. Once the safety zone is clear of marine 
mammals, the observer will advise that seismic surveys can re-commence. 
The ``ramp-up'' procedure will then be followed.
Ramp-up Procedure
    A ``ramp-up'' procedure will be followed when the airgun arrays 
begin operating after a specified-duration period without airgun 
operations. Under normal operational conditions (vessel speed 4-5 
knots), a ramp-up would be required after a ``no shooting'' period 
lasting 2 minutes or longer. At 4 knots, the source vessel would travel 
247 m (810 ft) during a 2-minute period. If the towing speed is reduced 
to 3 knots or less, as sometimes required when maneuvering in shallow 
water, it is proposed that a ramp-up would be required after a ``no 
shooting'' period lasting 3 minutes or longer. At towing speeds not 
exceeding 3 knots, the source vessel would travel no more than 277 m 
(909 ft) in 3 minutes. These guidelines would require modification if 
the normal shot interval were more than 2 or 3 min, but that is not 
expected to occur during the Storegga slide cruise.
    Ramp-up will begin with the smallest gun in the 6-gun array (80 
in\3\). Guns will be added in a sequence such that the source level of 
the array will increase in steps not exceeding 6 dB per 5-minute period 
over a total duration of approximately 14 min. During the ramp-up 
procedures, the safety zone for the full gun array will be maintained. 
Ramp-up will not occur for the 2-GI gun array, since the total air 
discharge volume for this array is small (210 in\3\).

Monitoring and Reporting

    LDEO proposes to conduct marine mammal monitoring of its 2003 
Storegga slide seismic program in the Norwegian Sea and acoustical 
verification of safety radii, in order to satisfy the anticipated 
requirements of the IHA.

Vessel-based Visual Monitoring

    The observer(s) will systematically scan the area around the vessel 
with 7 X 50 Fujinon reticle binoculars or with the naked eye during the 
daytime. At night, night vision equipment will be available (ITT F500 
Series Generation 3 binocular image intensifier or equivalent). Laser 
rangefinding binoculars (Bushnell Lytespeed 800 laser rangefinder with 
4 optics or equivalent) will be available to assist with distance 
estimation. If a marine mammal is seen well outside the safety radius, 
the vessel may be maneuvered to avoid having the mammal come within the 
safety radius (see Mitigation). When mammals are detected within or 
about to enter the designated safety radii, the airguns will be shut 
down immediately. The observer(s) will continue to maintain watch to 
determine when the animal is outside the safety radius. Airgun 
operations will not resume until the animal is outside the safety 
radius.
    At least one experienced marine mammal observer will be on duty 
aboard the seismic vessel, as well as a fishery expert (as likely 
required by the Norwegian Petroleum Directorate (2003)) and possibly 
one qualified contract biologist. Observers (appointed by LDEO) will 
complete a one-day training/refresher course on marine mammal 
monitoring procedures, given by a contract employee experienced in 
vessel-based seismic monitoring projects.
    Observers will be on duty in shifts of duration no longer than 4 
hours. Use of two simultaneous observers will increase the proportion 
of the marine mammals present near the source vessel that are detected. 
Bridge personnel additional to the dedicated marine mammal observers 
will also assist in detecting marine mammals and implementing 
mitigation requirements, and before the start of the seismic survey 
will be given instruction in how to do so.

Reporting

    The vessel-based monitoring will provide data required to estimate 
the numbers of marine mammals exposed to various received sound levels, 
to document any apparent disturbance reactions, and thus to estimate 
the numbers of mammals potentially taken by Level B harassment. It will 
also provide the information needed in order to shut down the airguns 
at times when mammals are present in or near the safety zones. When a 
mammal sighting is made, the following information about the sighting 
will be recorded: (1) 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 seismic vessel (e.g., none, 
avoidance, approach, paralleling, etc.), and behavioral pace; and (2) 
time, location, heading, speed, activity of the vessel

[[Page 44297]]

(shooting or not), sea state, visibility, cloud cover, and sun glare. 
The data listed under (2) will also be recorded at the start and end of 
each observation watch and during a watch, whenever there is a change 
in one or more of the variables.
    All mammal observations and airgun shutdowns will be recorded in a 
standardized format. Data will be entered into a custom database using 
a laptop computer when observers are off-duty. The accuracy of the data 
entry will be verified by computerized validity data checks as the data 
are entered and by subsequent manual checking of the database. These 
procedures will allow initial summaries of data to be prepared during 
and shortly after the field program, and will facilitate transfer of 
the data to statistical, graphical or other programs for further 
processing and archiving.
    Results from the vessel-based observations will provide (1) the 
basis for real-time mitigation (airgun shutdown); (2) information 
needed to estimate the number of marine mammals potentially taken by 
harassment, which must be reported to NMFS; (3) data on the occurrence, 
distribution, and activities of marine mammals in the area where the 
seismic study is conducted; (4) information to compare the distance and 
distribution of marine mammals relative to the source vessel at times 
with and without seismic activity; and (5) data on the behavior and 
movement patterns of marine mammals seen at times with and without 
seismic activity.
    A report will be submitted to NMFS within 90 days after the end of 
the seismic program in the Storegga slide area. The end of the Storegga 
slide program is predicted to occur on or about September 25, 2003. The 
report will cover the seismic surveys in the Storegga slide area and 
will be submitted to NMFS, providing full documentation of methods, 
results, and interpretation pertaining to all monitoring tasks. The 90-
day report will summarize the dates and locations of seismic 
operations, sound measurement data, marine mammal sightings (dates, 
times, locations, activities, associated seismic survey activities), 
and estimates of the amount and nature of potential ``take'' of marine 
mammals by harassment or in other ways.

Endangered Species Act (ESA)

    Under section 7 of the ESA, NMFS has begun consultation on the 
proposed issuance of an IHA under section 101(a)(5)(D) of the MMPA for 
this activity. Consultation will be concluded prior to the issuance of 
an IHA.

National Environmental Policy Act (NEPA)

    The NSF has prepared an EA for the Storegga slide survey. NMFS is 
reviewing this EA and will either adopt it or prepare its own NEPA 
document before making a determination on the issuance of an IHA. A 
copy of the NSF EA for this activity is available upon request (see 
ADDRESSES).

Preliminary Conclusions

    NMFS has preliminarily determined that the impact of conducting a 
seismic survey program in the Storegga slide portion of the southern 
Norwegian Sea will result, at worst, in a temporary modification in 
behavior by certain species of marine mammals. This activity is 
expected to result in no more than a negligible impact on the affected 
species.
    While the number of potential incidental harassment takes will 
depend on the distribution and abundance of marine mammals in the 
vicinity of the survey activity, the number of potential harassment 
takings is estimated to be small. In addition, no take by injury and/or 
death is anticipated, and the potential for temporary or permanent 
hearing impairment is low and will be avoided through the incorporation 
of the mitigation measures mentioned in this document. In addition, the 
proposed seismic program is not expected to interfere with any 
subsistence hunts, since operations in the whaling and sealing areas 
will be limited.

Proposed Authorization

    NMFS proposes to issue an IHA to LDEO for conducting a seismic 
survey program in the Storegga slide portion of the southern Norwegian 
Sea, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. NMFS has preliminarily 
determined that the proposed activity would result in the harassment of 
small numbers of marine mammals; would have no more than a negligible 
impact on the affected marine mammal stocks; and would not have an 
unmitigable adverse impact on the availability of stocks for 
subsistence uses.

Information Solicited

    NMFS requests interested persons to submit comments and information 
concerning this request (see ADDRESSES).

    Dated: July 21, 2003.
Laurie K. Allen,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 03-19035 Filed 7-25-03; 8:45 am]
BILLING CODE 3510-22-S