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Small Takes of Marine Mammals Incidental to Specified Activities; Oceanographic Surveys in the Hess Deep, Eastern Equatorial Pacific Ocean
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: July 11, 2003 (Volume 68, Number 133)]
[Notices]
[Page 41314-41321]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11jy03-36]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 021203A]
Small Takes of Marine Mammals Incidental to Specified Activities;
Oceanographic Surveys in the Hess Deep, Eastern Equatorial Pacific
Ocean
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice of issuance of an incidental harassment authorization.
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SUMMARY: In accordance with provisions of the Marine Mammal Protection
Act (MMPA) as amended, notification is hereby given that an Incidental
Harassment Authorization (IHA) to take small numbers of marine mammals,
by harassment, incidental to conducting oceanographic surveys in the
Hess Deep in international waters of the Eastern Equatorial Pacific
Ocean has been issued to Lamont-Doherty Earth Observatory (L-DEO).
DATES: Effective from July 3, 2003, through June 30, 2004.
ADDRESSES: The application, a list of references used in this document,
and/or the IHA are available by writing to Kaja A. Brix, Acting Chief,
Marine Mammal Conservation Division, Office of Protected Resources,
National Marine
[[Page 41315]]
Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-
3225, or by telephoning the contact listed here.
FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of
Protected Resources, NMFS, (301) 713-2055, ext 128,
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.
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 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 [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].
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
small numbers 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 January 29, 2003, NMFS received an application from L-DEO for
the taking, by harassment of several species of marine mammals
incidental to conducting a seismic survey program in the Hess Deep
portion of the Eastern Equatorial Pacific Ocean about 600 nautical
miles (nm)(690 land miles; 1111.2 km) west of the Galapagos Islands
during March and April 2003, but rescheduled for July, 2003. The
purpose of this survey is to obtain information on movements of the
earth's plates and on formations associated with those movements. More
specifically, the Hess Deep survey will obtain information on the
geologic nature of boundaries of the earth's crust at fast-spreading
and intermediate-spreading ridges at the boundaries of tectonic plates.
Description of the Activity
The seismic survey will involve a single vessel, the R/V Maurice
Ewing (Ewing), which will deploy and retrieve the Ocean Bottom
Seismometers (OBSs) and conduct the seismic work. The 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.
Water depths in the Hess Deep survey area will range from
approximately 2,000 to 3,400 m (6,560 to 11,150 ft). A total of 912 km
(492 nm) of MCS (Multi Channel Seismic) surveys using a 10-gun array
and 189 km (102 nm) of OBS surveys using a 12-gun array are planned to
be conducted. These line-kilometer figures represent the planned
production surveys. 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 L-DEO, (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, sometimes in combination with OBS
receivers placed on the bottom. 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 at most times during the Hess Deep survey.
The Ewing will be used as the source vessel. It will tow the airgun
array (either 10 or 12 guns) 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 60-90
seconds (OBS lines) and approximately 20 seconds (all other lines). The
20-sec spacing corresponds to a shot interval of about 50 m (164 ft).
The 60-90 sec spacing along OBS lines is to minimize previous shot
noise during OBS data acquisition, and the exact spacing will depend on
water depth. The 10-gun array will be used during MSC surveys and the
12 gun-array will be used during OBS surveys. The airguns will be
widely spaced in an approximate rectangle with dimensions 35 m (114.9
ft)(across track) by 9 m (29.5 ft)(along track). Individual airguns
range in size from 80 to 850 in3, with total volumes of the arrays
being 3050 and 3705 in3 for the 10- and 12-gun arrays, respectively.
The 10-airgun array will have a peak sound source level of 248 dB
re 1 [mu]Pa or 255 dB peak-to-peak (P-P). The 12-airgun array will have
a peak sound source level of 250 dB re 1 [mu]Pa or 257 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 10 or 12
sources. Because the actual source is a distributed sound source (10 or
12 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
than sounds projected directly beneath the array.
Along selected lines, OBSs will be positioned by the Ewing prior to
the time when it begins airgun operations in that area. After OBS lines
are shot, the Ewing will retrieve the OBSs, download the data, and
refurbish the units.
Along with the airgun operations, one additional acoustical data
acquisition activity will occur throughout most of the cruise. The
ocean floor will be mapped with an Atlas Hydrosweep DS-2, multi-beam
15.5-kHz bathymetric sonar (Atlas Hydrosweep). The Atlas Hydrosweep is
mounted in the hull of the Ewing, and it operates in three modes,
depending on the water depth. The first mode is when water depth is
<400 [mu](<1312.3 ft). The source output is 210 dB re 1 [mu]Pa-m rms
and a single 1-
[[Page 41316]]
millisec (msec) pulse or ``ping'' per second is transmitted, with a
beam-width of 2.67 degrees fore-aft and 90 degrees in beam-width. The
beam-width 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 [mu]s) 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 msec in water
depths <500 m (<1640.4 ft) and 10 msec in the deepest water. Additional
information on the airgun array and Atlas Hydrosweep specifications is
contained in the application, which is available upon request (see
ADDRESSES).
Comments and Responses
A notice of receipt of the L-DEO application and proposed IHA was
published in the Federal Register on April 14, 2003 (68 FR 17909). That
notice described in detail the proposed activity, including the
characteristics of the Ewing's acoustic sources, the marine mammal
species that may be affected by the activity, and the anticipated
effects on marine mammals. That information is not repeated here.
During the 30-day public comment period, comments were received from
the Marine Mammal Commission (Commission) and the Center for Biological
Diversity (CBD).
Activity Concerns
Comment 1: The CBD believes that the proposed authorization is
flawed because it lacks a disclosure and analysis of the impacts of the
multi-beam bathymetric sonar planned for use on this voyage. The
proposed authorization indicates that the dB level of this sonar is
210-220 dB rms, yet concludes without sufficient analysis that the
sonar is unlikely to result in any take by harassment.
Response: A complete description of the Atlas Hydrosweep is
contained in the proposed IHA document (68 FR 17916, April 14, 2003),
pages 54-56 of the L-DEO application, and pages 65-66 of the National
Science Foundation (NSF) Environmental Assessment (EA). The reason for
concluding that the Atlas Hydrosweep is unlikely to result in a take by
harassment is contained in those documents. In summary, any given
marine mammal at depth near the Ewing trackline would be in the main
beam for only 1/5th or at most 2/5th of the 1 10 msec duration of the
signal. The Atlas Hydrosweep is less powerful, has a shorter pulse
duration and projects downwards as compared to standard Navy sonars
that have been linked to avoidance reactions and stranding of
cetaceans. Also, because the area of possible influence of the Atlas
Hydrosweep is much smaller (a narrow band below the source vessel),
marine mammals that encounter the Atlas Hydrosweep at close range are
unlikely to be subjected to repeated pulses because of the narrow fore-
aft width of the beam, and will receive only limited amounts of pulse
energy because of the short pulses. This effectively eliminates a
marine mammal receiving the additional acoustic stimulus needed to
induce a significant behavioral response.
Marine Mammal Impact Concerns
Comment 2: The CBD notes that the proposed IHA Federal Register
document states that approximately 8,901 marine mammals will be taken
by the 10-gun and 12-gun array with peak source levels of 255 dB P-P
(peak-to-peak) and 257 dB P-P (or approximately 239 rms (root-mean-
squared) and 241 rms). According to the CBD, this does not constitute
``small numbers'' of marine mammals.
Response: Section 101(a)(5)(D) of the MMPA authorizes takings of
marine mammals incidental to an applicant's activity if, among other
things, the incidental taking, by harassment, is of small numbers of
marine mammals of a species or population stock. The regulations at 50
CFR 216.103 define ``small numbers'' to mean ``a portion of a marine
mammal species or stock whose taking would have a negligible impact on
that species or stock.'' An activity would affect ``small numbers'' of
a species or stock when it is determined that the total taking (of the
species or stock by the activity over the period of the authorization)
will be small relative to the estimated population size and relevant to
the behavioral, physiological, and life history characteristics of the
species. In other words, NMFS considers the kind of take (e.g.,
mortality, injury, or harassment); an individual mammal's hearing
ability, and the affected species hearing capability in the frequency
of the subject anthropogenic sounds; and the robustness of the affected
marine mammal populations when determining whether the incidental
taking would be small. There is no requirement that the total
cumulative taking of all species be small.
Table 7 in the application (and referenced in the proposed
authorization notice) provides an estimate of the number of animals
that might be exposed to a sound pressure level (SPL) of 160 dB (RMS)
or greater. This does not necessarily mean that 100 percent of all
marine mammals exposed to seismic sounds will have a significant
disruption in a biologically important activity at 160 dB. It is likely
that some lower percentage would be affected either because of the
hearing ability of the affected species or an individual animal to the
projected frequencies. For example, Table 7 provides estimates of the
number of animals of the 13 species of Delphinidae that might be
exposed to received levels [gteqt]
160 dB. However, the 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 Delphinidae for onset
of Level B harassment in response to seismic sounds is at about 170 dB.
However, based on either sound pressure level, Level B harassment
take levels for almost every species would be significantly less than 1
percent of the affected stock and one could reach a level of 2 percent.
Since this activity will not result in mortality or serious injury of
any marine mammals and has the potential to result in the incidental
behavioral (Level B) harassment of only a small percentage of the
estimated population size of affected stocks, NMFS has concluded that
the takings will be small.
Comment 3: The CBD states that NMFS has not demonstrated that the
level of take will have a ``negligible impact.'' The drafters of the
MMPA's small take provision defined ``negligible impact'' as an impact
that is ``so small or unimportant or of so little consequence as to
warrant little or no attention'' (H. Rept. 228, 97th Cong. 1st sess. 19
(1981)). According to the proposed IHA, animals subjected to sound
levels above 160 dB may alter their behavior and distribution. The take
by harassment of 8,901 marine mammals by underwater noise far exceeding
the thresholds for harassment and injury is not negligible. The Ewing
should not be permitted to use the 10-
[[Page 41317]]
gun and 12-gun array at the planned levels.
Response: The definition quoted in the comment was modified by
Public Law 99-659 when Congress expanded the small take authorization
to include marine mammal species listed under the ESA. NMFS interprets
negligible impact to mean that the impact resulting from the specified
activity cannot reasonably be expected to, and is not reasonably likely
to, adversely affect the species or stock through effects on
reproduction or survival. NMFS believes that this definition of
negligible impact captures Congressional intent since it adopted,
substantially without change, the definition set out in the Senate's
``Section-by-Section Analysis'' (132 Cong. Rec. S16305 (October 15,
1986)).
Discussion regarding the potential for taking by Level B harassment
of up to 8,901 marine mammals is provided in the previous response. As
required by the MMPA, L-DEO has provided significant documentation in
its application that the harassment of marine mammals incidental to
conducting a scientific survey using a seismic array will have a
negligible impact on affected species and stocks of marine mammals.
NMFS concurs with this finding and believes that the information
contained in the L-DEO application and the NSF EA is a compilation of
the best scientific information available on this subject. NMFS is
unaware of additional scientifically-based information on which to make
an alternative decision and the commenter has not provided any
information to support the statement. Refer to the proposed
authorization notice (68 FR 17909, April 14, 2003) for discussion on
potential seismic noise impacts on marine mammals.
Mitigation Concerns
Comment 4: The CBD states that while the proposed IHA notice
outlines several mitigation measures the action will include, these
measures do not ensure the ``least practicable adverse impact'' as
required by the MMPA. It is unclear from the proposed IHA that the
safety radii dB levels are sufficient to protect marine mammals (from
injury). It appears that L-DEO determined the safety radii based on
exposure to 180 dB (cetaceans) and 190 dB (pinnipeds). These levels are
far too high to be deemed ``safety'' radii and should be modified
accordingly.
Response: The safety radii are based on the findings of two public
workshops (High-Energy Seismic Survey (HESS) Workshop, June 12-13,
1997; NMFS Acoustic Criteria Workshop, September, 1998). A panel of
nine experts in marine biology and acoustics sponsored by Southern
California's HESS Team convened to develop marine mammal exposure
criteria (Knastner, 1998). The consensus of the experts was that they
were
apprehensive about levels above 180 dB re 1 [mu]Pa (rms) with
respect to overt behavioral, physiological, and hearing effects on
marine mammals in general. Therefore, the 180-dB radius, as
initially defined by transmission loss model and verified on-site,
is recommended as the safety zone distance to be used for all
seismic surveys within the southern California study area.
The 1998 NMFS workshop clarified that, because pinniped hearing is
different from that of cetaceans, 190 dB would be a safe level
preventing pinniped injury from exposure to impulse sounds.
While there is limited empirical evidence on injury at levels below
180 dB, the 180- and 190-dB levels make sense, given that Frankel
(1994) estimated the source level for singing humpback whales to be
between 170 and 175 dB while Au and Andrews (2001) measured humpback
whale calls off Hawaii at 189 dB; the average call source level for
blue whales was calculated by McDonald et al. (2001) to be 186 dB;
Watkins et al. (1987) and Charif et al. (2002) found source levels for
fin whales up to 186 dB; and M hl et al. (2000) recorded source levels
for sperm whale clicks up to 223 dB. If marine mammals vocalize at
these levels, it is realistic to believe that these species have also
evolved mechanisms to protect themselves and conspecifics from high
SPLs.
Comment 5: The CBD states that it is far from clear that the
vessel-based observers will detect marine mammals in the area in order
to trigger the necessary shutdown of operations. For example, Cuvier's
beaked whales in the vicinity of the airgun array and sonar are likely
to escape observance due to the documented extreme difficulty in
detecting this species.
Response: The MMPA requires NMFS to ensure that takings are at the
lowest level practicable. The mitigation measures, which include (1)
course alteration; (2) power-down procedures; (3) ramp-up procedures;
and (4) vessel-based observers, are discussed in detail later in this
document (see Mitigation). In combination, they are more likely to be
effective mitigation than the use of observers alone. These same
measures are included in the Interim Operational Guidelines for High-
Energy Seismic Surveys off Southern California (HESS, 1999) and are
standard mitigation measures for high-energy seismic sources used in
the Beaufort Sea and other areas. NMFS reviewed the practicality of
adding other mitigation measures, and has added an additional measure
discussed later in this document (see Monitoring Concerns) and
clarified timing for events such as ramp-up and observation periods
(see Mitigation). Other mitigation measures, such as aircraft
overflights and limiting operations to daylight hours, are not
practicable. Overflights, for example, in addition to the prohibitive
cost, would be unable to spend much time in the area for observation
after flying 600 nm (1111.2 km) from the Galapagos Islands. Therefore,
NMFS determined that the takings, by Level B harassment, are at the
lowest level practicable without compromising the ability of L-DEO to
obtain the scientific information on movements of the earth's plates
and on formations associated with those movements at the Hess Deep.
Monitoring Concerns
Comment 6: The Commission believes that NMFS' preliminary
determinations are reasonable, provided NMFS is satisfied that the
proposed mitigation and monitoring activities are adequate to detect
marine mammals in the vicinity of the proposed operations and ensure
that marine mammals are not being taken in unanticipated ways or
numbers. In this regard, NMFS' Federal Register notice and the
application state that ``[v]essel-based observers will monitor marine
mammals near the seismic source vessel during all daylight airgun
operations and during any nighttime startups of the airguns;'' and that
bridge personnel will watch for marine mammals during nighttime
activities but that ``[o]bservers will not be on duty during ongoing
seismic operations at night.'' The Federal Register notice states that
an image-intensifier night-vision devices (NFDs) will be available for
use at night, although past experience has shown that NFDs are of
limited value for this purpose.'' Thus it is unclear that, for
nighttime activities, the monitoring effort will be sufficient to
determine that no marine mammals are within the safety zones at start-
up or will be an effective means of detecting when marine mammals enter
the safety zones during operations such that activities are suspended
before received levels of 180 and 190 dB (rms) are reached.
Response: As part of the IHA, NMFS is requiring that if the airguns
are started up at night, two marine mammal observers will monitor for
marine mammals within the safety radii for 30 minutes prior to start up
using night vision devices as described later (see Monitoring and
Reporting). If the entire
[[Page 41318]]
safety radii is not visible for 30 minutes prior to ramp-up in either
daylight or nighttime, ramp-up may not commence unless at least one
airgun has maintained an SPL of at least 180 dB (rms) during the
interruption of seismic survey operations. This latter IHA condition
ensures that marine mammals will have sufficient opportunity to move
away from the track of the Ewing prior to receiving high dB levels. The
combination of the two conditions ensures, to the greatest extent
practicable, that no mammals will be within the appropriate safety
zones whenever the airguns are turned on, either in daylight or
nighttime.
However, it is noted that at times, pinnipeds and even some small
cetaceans will actively approach a vessel during transmissions (the
vessel itself moving forward at about 3-5 knots) from the side of the
vessel or the stern, meaning that the animal is voluntarily approaching
a noise source that is increasing in strength as the animal gets
closer. Experience indicates that pinnipeds will come from great
distances to scrutinize seismic-reflection operations. Seals have been
observed swimming within airgun bubbles only 10 m (33 ft) away from
active arrays. Also, Canadian scientists, who were using a high-
frequency seismic system that produced sound frequencies closer to
pinniped hearing than those used by the Ewing, describe how seals
frequently approached close to the seismic source, presumably out of
curiosity. Therefore, because at least pinnipeds indicated no adverse
behavioral reaction to seismic noise, NMFS has concluded that the
above-mentioned mitigation requirement is reasonable because the
bridge-watch will be concentrating on marine mammals approaching the
vessel from the bow. Also, the night-vision ability of the trained
bridge-watch staff will be better than observers elsewhere on the
vessel where normal ship-board lighting is more likely. Finally, an
observer is still required to be on standby, meaning his/her presence
would be in the vicinity of the bridge and is not precluded from
conducting observations during night-time.
Comment 7: The Commission notes that there is no discussion on why
nighttime operations are considered necessary.
Response: The daily cost to the Federal government to operate the
Ewing is approximately $33,000-$35,000/day, or approximately $350,000
for this 10-day research cruise (Ljunngren, pers. comm. May 28, 2003).
If the Ewing is prohibited from operating during nighttime, the 10-day
trip would require an additional 3-5 days, or up to $105,000-175,000
more, depending upon average daylight at the time of the work.
Therefore, because NMFS has determined that the safety zone must be
visible during ramp-up, and because once the Ewing is underway and
ramp-up completed, mammals will have sufficient notice of a vessel
approaching (at least one hour) to avoid the approaching array if the
sounds are annoying, NMFS determined that it is neither practical nor
necessary to limit seismic operations to daylight hours since marine
mammal are unlikely to be injured. Finally, with an extension of the
time needed to complete the work if limited to daylight only
operations, ship time would likely be limited for scheduled future
research projects, possibly resulting in the utilization of alternative
vessels.
Comment 8: The Commission notes that it is unclear whether vessel-
based passive acoustic monitoring will be conducted as an adjunct to
visual monitoring during daytime and particularly during nighttime
operations to detect, locate, and identify marine mammals, and, if not,
why not.
Response: The passive acoustical monitoring equipment that was used
onboard the Ewing during the 2003 Gulf of Mexico (GOM) Sperm Whale
Seismic Study (SWSS), is not the property of L-DEO or the Ewing, and
therefore is not available for the Hess Deep cruise. As a result of
this comment, L-DEO is evaluating the scientific results of the passive
sonar from the SWSS trip to determine whether it is practical to
incorporate into future seismic research cruises. NMFS expects a report
on this analysis within 90 days of completion of the SWSS cruise.
Comment 9: The Commission asks whether conducting monitoring for at
least 30 minutes prior to the planned start of airgun operations during
the day and at night is sufficient, particularly for detecting the
presence of species that make long dives.
Response: A 30-minute observation period is practical and NMFS
believes it is unnecessary to lengthen this period considering that the
ramp-up period will increase SPLs at a rate no greater than 6 dB per 5-
minutes for a total ramp-up duration of approximately 18-20 min for the
10-12 gun arrays. Also, while some whale species may dive for up to 45
minutes, it is unlikely that the ship's bridge watch would miss a large
whale surfacing from its previous dive if it is within a mile or two of
the vessel.
Endangered Species Act (ESA) Concerns
Comment 10: The CBD believes that NMFS and NSF have not yet
completed consultation under section 7 of the ESA. As this research
voyage will impact endangered species, including blue and sperm whales,
the CBD expects that NMFS and NSF will complete consultation prior to
authorizing this action and will forward a copy of the resulting
documentation to the CBD.
Response: NMFS has completed consultation on this action and has
forwarded a copy of the Biological Opinion, the NSF EA, and the L-DEO
application to the CBD as requested in its letter.
Mitigation
For the seismic operations in the Hess Deep, a 12-gun array with a
total volume of 3705 in3 and a 10-gun array of 3050 in3 will be used.
The airguns comprising these arrays will be spread out horizontally, so
that the energy from the array will be directed mostly downward. The
directional nature of the two alternative airgun arrays to be used in
this project is an important mitigating factor, resulting in reduced
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. Also, the use of the 10- or 12-gun array of 3,050
or 3,705 in3 rather than the largest airgun array that the L-DEO's
source vessel can deploy (20 airguns totaling almost 8,600 in3) is
another significant mitigation measure.
Safety Radii
Modeled results for the 10- and 12-gun arrays indicate that the
180-dB (re 1 [mu]Pa (rms)) isopleths (i.e., the current potential
injury threshold for cetaceans) are 830 and 880 m (2,723 and 2,887 ft),
respectively. The radii around the 10- and 12-gun arrays corresponding
to the 190 dB (re 1 [mu]Pa (rms)) isopleths (the current potential
injury threshold for pinnipeds), are estimated as 250 and 300 m (820
and 984 ft), respectively. A calibration study was conducted prior to
this survey to determine the actual radii corresponding to each sound
level. These actual radii will be implemented for this study. Until
then, or if those measurements appear defective, L-DEO will use a
precautionary 1.5 times the 180-dB and 190-dB radii predicted by the
model as the safety radii. Under those circumstances, the safety radii
for cetaceans would be 1,245 and 1,320 m (4,085 and 4,331 ft),
respectively, for the 10- and 12-gun arrays, and the safety radii for
pinnipeds would be 375 and 450 m (1,230 and 1,476 ft), respectively.
[[Page 41319]]
Power-down Procedures
Vessel-based observers will monitor marine mammals near the seismic
vessel during daylight and for 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 where there is a potential for injury (based on
the 180- and 190-dB criteria). The power-down procedure should be
accomplished within several seconds or a single seismic ``ping'' of the
determination being made that a marine mammal is within or about to
enter the safety zone.
Restart Procedures
After a power-down of the airguns, the observer(s) will maintain
watch to determine when the animal is outside the safety radius. Airgun
transmissions can commence/ resume after the mammal(s) is observed to
have left the safety zone or 15 minutes (for small odontocetes and
pinnipeds) or 30 minutes (for mysticetes/large odontocetes (sperm,
pygmy sperm, dwarf sperm, beaked, and bottlenose whales)) from the last
visual detection of the mammal(s) within the safety zone. Once the
safety zone is clear of marine mammals, the observer will advise that
restart procedures can commence.
A 30-minute pre-ramp-up observation period must be conducted after
a shutdown (but not after power-down) of the array for a length of time
greater than it would take a seismic vessel to travel the distance to
the 160-dB isopleth at the time of shutdown. For example, traveling at
4.0 knots (4.0 nm/hr), the Ewing would need about 1 hr to reach that
isopleth while operating the 10-gun array and 1.25 hrs when using the
12-gun array. For this cruise, the IHA requires the 30-minute
observation period to take place after a shut-down of 1 hour or more.
The ``ramp-up'' procedure will then be followed.
Ramp-up Procedure
L-DEO will use the standard ``ramp-up'' (soft-start) procedure when
the airgun arrays begin operating after a period without any airgun
operations as specified in this paragraph. From a shut-down, ramp-up
will begin with the smallest gun in the array that is being used (80
in3 for the 10- and 12-gun arrays), 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-minutes for a total ramp-up duration of
approximately 18-20 min (10-12 gun arrays). 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 (not a factor in Hess Deep), ramp-up
is 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 procedures would
require modification if the normal seismic shot interval were more than
2 or 3 min, but that is not expected to occur during the Hess Deep
project.
Course Alteration
If a marine mammal is detected outside its safety radius and, based
on its position and 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 to avoid the marine mammal entering the safety radius, but 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 safety radius, further mitigative actions
will be taken, i.e., either further course alterations or power-down of
the airguns. The Ewing is required to adopt this mitigation measure
during the Hess Deep seismic survey program provided that doing so will
not compromise operational safety requirements.
Marine Mammal Monitoring
L-DEO will conduct marine mammal monitoring during its seismic
program in the Hess Deep in order to verify that the taking of marine
mammals, by harassment, incidental to conducting the seismic survey
will have a negligible impact on marine mammal stocks and to ensure
that these harassment takings are at the lowest level practicable.
A minimum of two marine mammal observers will be onboard the Ewing
to monitor marine mammals near the seismic vessel. Observers will watch
for marine mammals during all daylight periods with seismic shooting,
and for at least 30 minutes prior to any start-up of airgun operations
after shutdown. At least one observer must have previous observation
experience. Prior to seismic operations commencing, observers must
complete a 1-day training/refresher course on marine mammal monitoring
procedures, given by a contract employee experienced in vessel-based
seismic monitoring projects. The Ewing is considered 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, allowing for good visibility within a 210[deg]
arc for each
observer. Airgun operations will be suspended and the source powered-
down whenever marine mammals are observed within, or about to enter,
designated safety zones.
Observers will be on duty in shifts of duration no longer than 4
hours. The second observer will also be on watch part of the time,
including the 30-minute periods preceding startup of the airguns and
during ramp ups. Use of two simultaneous observers will decrease the
potential that marine mammals near the source vessel will be missed.
Bridge personnel that are additional to the dedicated observers will
also assist in detecting marine mammals and implementing mitigation
requirements, and before the start of the seismic survey will be given
proper instruction for observing and reporting marine mammals and sea
turtles.
Observers will not normally be on duty during ongoing seismic
operations at night; bridge personnel will watch for marine mammals
during this period and will immediately call for the airguns to be
powered down and the stand-by observer will be notified if marine
mammals are observed in or about to enter the safety radii. However, if
the airguns are started up at night after a shutdown duration of 1 hour
or greater, two observers will monitor for marine mammals within the
safety radii for 30 minutes prior to beginning ramp-up using night
vision devices (NVDs), although NMFS notes that past experience has
shown that NVDs are of limited value for this purpose. If the complete
safety radii are not visible for at least 30 minutes prior to ramp-up
in either daylight or nighttime, ramp-up may not commence unless the
seismic source has maintained an SPL of at least 180 dB during the
interruption of seismic survey operations. While the 30-minute
observation period is only required prior to commencing seismic
operations following an extended shut down period, if ramp-up
procedures must be performed at night, the two observers must be on
duty 30 minutes prior to the start of seismic shooting and during the
ramp-up procedures.
The observer(s) will watch for marine mammals from the bridge, the
highest practical vantage point on the vessel. The observer(s) will
systematically scan
[[Page 41320]]
the area around the vessel with 7 X 50 Fujinon reticle binoculars or
with the naked eye during the daytime. At night, NVDs will be available
(ITT F500 Series Generation 3 binocular image intensifier or
equivalent), and used, if necessary. Laser rangefinding binoculars
(Bushnell Lytespeed 800 laser rangefinder with 4 optics or equivalent)
will be available to assist with distance estimation.
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 power-down the airguns
at times when mammals are present in or near the safety zone. Results
from the vessel-based observations will provide (1) the basis for real-
time mitigation (airgun power-down); (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.
Reporting
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
(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 power-downs 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.
A draft report will be submitted to NMFS for review within 90 days
after the end of the seismic program in the Hess Deep area which is
predicted to occur on or about July 28, 2003. The draft report will
cover the seismic surveys in the Hess Deep area and will provide full
documentation of methods, results, and interpretation pertaining to all
monitoring tasks. The draft 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. The draft
report will be considered the final report unless comments and
suggestions are provided by NMFS within 60 days of its receipt of the
draft report.
Estimates of Take by Harassment for the Hess Deep Cruise
As described previously (see 68 FR 17909, April 14, 2003) and in
the L-DEO application, animals subjected to sound levels above 160 dB
may alter their behavior or distribution, and therefore might be
considered to be taken by Level B harassment.
Based on summer marine mammal survey data collected by NMFS and
density calculations by Ferguson and Barlow (2001), L-DEO used their
average marine mammal density to compute a ``best estimate'' of the
number of marine mammals that may be exposed to seismic sounds
[gteqt]160 dB re 1[mu]Pa (rms). The average densities were then
multiplied by the proposed survey effort (912 and 189 km for the 10-gun
and 12-gun array, respectively) and twice the 160 dB safety radius from
the source vessel (the 160-dB radius was 6.5 and 7.25 km for the 10-gun
and 12-gun array, respectively) to estimate the ``best estimate'' of
the numbers of animals that might be exposed to sound levels [gteqt]160
dB re 1[mu]Pa (rms) during the proposed seismic survey program.
Separate estimates were made for the 10-gun and 12-gun arrays because
the 160-dB radius was different for the two arrays (see Tables 5 and 6
in L-DEO (2003)). Based on this method, Table 7 in LDEO (2003) provided
a ``best estimate'' of the number of marine mammals (by species) that
would be exposed to [gteqt]160 dB (rms), and thus potentially taken by
Level B harassment, during the proposed survey, by both the 10-gun and
12-gun arrays. Twelve animals would be endangered species, sperm whales
(11) and a single blue whale, while two stocks of dolphins would
account for 96 percent of the overall estimate for potential taking by
harassment.
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 (3.2-4.3
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 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 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 areas where
seismic surveys are proposed. L-DEO's ``best estimate'' is that 10
Bryde's whales, or 0.1 percent of the estimated Eastern Equatorial
Bryde's whale population, will be exposed to sound levels [gteqt]160 dB
re 1 [mu]Pa (rms) and potentially affected, and 1 blue whale, or 0.1
percent of the endangered ETP blue whale population, would receive
[gteqt]160 dB. Therefore, these potential takings by Level B harassment
will have a negligible impact on their populations.
Larger numbers of odontocetes may be affected by the seismic survey
activities, but the population sizes of the main species are large and
the numbers potentially affected are small (<0.1 percent) relative to
the population sizes. The total number of odontocetes that might be
exposed to [gteqt]160 dB (re 1 [mu]Pa
[[Page 41321]]
(rms)) in the Hess Deep area is estimated as 8,890. Of these, 8,532 are
delphinids, and of these about 3,076 might be exposed to [gteqt]170 dB.
Both estimates are <0.1 percent of the eastern equatorial populations
of these species.
As noted earlier in this document, NMFS believes that Level B
harassment take levels would, for almost every affected stock, be
significantly less than 1 percent of the stock and only a single stock
has the potential of reaching a level of 2 percent for Level B
harassment.
Effects on Pinnipeds
Very few if any pinnipeds are expected to be encountered in the
Hess Deep area. Thus, a maximum of 20 pinnipeds in the Hess Deep 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.
Determinations
Based on the information contained in the L-DEO application, the
NSF EA, the April 14, 2003, proposed authorization notice (68 FR 17909)
and this document, NMFS has determined that conducting a seismic survey
by the Ewing at the Hess Deep in the eastern equatorial Pacific Ocean
in 2003 by L-DEO would result in the harassment of small numbers of
marine mammals; would have no more than a negligible impact on the
affected marine mammal species or stocks; and would not have an
unmitigable adverse impact on the availability of stocks for
subsistence uses. This activity will result, at worst, in a temporary
modification in behavior by affected species of marine mammals. While
behavioral modifications may be made by these species as a result of
seismic survey activities, this behavioral change is expected to result
n no more than a negligible impact on the affected species. Also, while
the number of actual 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 and required under the
IHA. For these reasons therefore, NMFS has determined that the
requirements of section 101(a)(5)(D) of the MMPA have been met and the
authorization can be issued.
Consultation
NMFS has concluded consultation under section 7 of the ESA on NMFS'
issuance of an IHA to take small numbers of marine mammals, by
harassment, incidental to conducting calibration measurements of its
seismic array in the Hess Deep by L-DEO. The finding of that
consultation was that this study is not likely to jeopardize the
continued existence of marine species listed as threatened or
endangered under the ESA. No critical habitat has been designated for
these species in the equatorial Pacific Ocean; therefore, none will be
affected. A conservation recommendation was made to ensure that the
safety zone is clear of sea turtles prior to ramp up. This
recommendation has been implemented through the IHA to L-DEO. A copy of
the Biological Opinion is available upon request (see ADDRESSES).
National Environmental Policy Act (NEPA)
On March 18, 2003, the NSF made a determination, based on
information contained within its EA that implementation of the subject
action is not a major Federal action having significant effects on the
environment within the meaning of Executive Order 12114. NSF determined
therefore, that an environmental impact statement would not be
prepared. On April 14, 2003 (68 FR 17909), NMFS noted that the NSF had
prepared an EA for the Hess Deep survey. In accordance with section
6.01 of the NOAA Administrative Order 216-6 (Environmental Review
Procedures for Implementing the National Environmental Policy Act, May
20, 1999), NMFS has reviewed the information contained in NSF's EA and
determined that the NSF EA accurately and completely describes the
proposed action alternative, reasonable additional alternatives, and
the potential impacts on marine mammals, endangered species, and other
marine life that could be impacted by the preferred alternative and the
other alternatives. As a result, NMFS has determined that it is not
necessary to issue either a new EA or a Supplemental EA for the
issuance of an IHA to L-DEO for this activity. Therefore, based on this
review and analysis, NMFS is adopting the NSF EA under NEPA. A copy of
the NSF EA for this activity is available upon request (see ADDRESSES).
Authorization
NMFS has issued an IHA to take small numbers of marine mammals, by
harassment, incidental to conducting a seismic survey by the Ewing in
the eastern equatorial Pacific Ocean to L-DEO for a 1-year period,
provided the mitigation, monitoring, and reporting requirements
described in this document and the IHA are undertaken.
Dated: July 3, 2003.
Laurie K. Allen,
Acting Director, Office of Protected Resources, National Marine
Fisheries Service.
[FR Doc. 03-17622 Filed 7-10-03; 8:45 am]
BILLING CODE 3510-22-S