[Federal Register Volume 68, Number 203 (Tuesday, October 21, 2003)]
[Notices]
[Pages 60086-60091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-26549]



[[Page 60086]]

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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 092203D]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Oceanographic Surveys in the Southeast Caribbean Sea and Adjacent 
Atlantic Ocean

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), a part of Columbia University, for an Incidental 
Harassment Authorization (IHA) to take small numbers of marine mammals, 
by harassment, incidental to conducting oceanographic surveys in the 
Southeast Caribbean Sea and adjacent Atlantic Ocean. 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 November 
20, 2003.

ADDRESSES: Comments on the application should be addressed to the 
Acting 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: Kimberly Skrupky, Office of Protected 
Resources, NMFS, (301) 713-2322, ext 163.

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.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
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).
    Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny issuance of the authorization.

Summary of Request

    On August 7, 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. As presently scheduled, a 
seismic survey will be conducted in the Southeast Caribbean Sea and 
Adjacent Atlantic Ocean. The Southeast Caribbean Sea and Atlantic Ocean 
cruise will be off the coast of Venezuela in an area extending from 
59[deg] to 71[deg] W and 10[deg] to 15[deg] N from January 11, 2004 to 
February 21, 2004. The operations will partly take place in the 
Exclusive Economic Zones (EEZ) of several nations in the Southeast 
Caribbean (including Venezuela, Aruba, Bonaire, Curacao, Trinidad, and 
Tobago) as well as in international waters.
    The purpose of the project is to obtain information on island arc 
movements and geometry which can be used to better understand the 
history and mechanical processes by which island arcs accrete to 
continents, deeply buried rocks are exhumed, and folded belts and 
different types of sedimentary basins form along oblique collision 
zones. The interplay of the crust and subcrustal lithosphere during arc 
accretion and metamorphic belt exhumation and subduction polarity 
reverses will be examined. In addition, the flow patterns of the 
sublithospheric mantle beneath the plate boundary and northern South 
America as a whole and beneath the right lateral shear zone between 
them will be examined.

Description of the Activity

    The seismic survey will involve two vessels which will conduct the 
seismic work. The source vessel, the R/V Maurice Ewing, will deploy an 
array of 20 airguns as an energy source, plus a 6-km (3.2 n.mi.) towed 
hydrophone streamer. A second vessel, the R/V Seward Johnson, will 
deploy and retrieve Ocean Bottom Seismometers (OBSs). As the airgun 
array is towed along the survey line, the towed hydrophone streamer or 
OBSs will receive the returning acoustic signals and transfer the data 
to the on-board processing system. Water depths within the study area 
range from approximately 15-6,000 m (49-19,685 ft). Most of the survey 
effort will take place in waters greater than 1,000 m (3,281 ft) deep, 
2,031 km (1,097 n.mi.) will be surveyed in water depth ranging from 
100-1,000 m (328-3,281 ft) deep, and a small portion of the survey 
effort will occur in shallow water less than 100 m (328 ft) deep.
    The procedures to be used for the seismic study will be similar to 
those used during previous seismic surveys by LDEO in the equatorial 
Pacific Ocean (Carbotte et al., 1998, 2000). The proposed seismic 
surveys will use conventional seismic methodology with a towed airgun 
array as the energy source, and a towed hydrophone streamer and/or OBSs 
as the receiver system. The OBSs will be deployed by the Seward 
Johnson. The energy to the airgun array is compressed air supplied

[[Page 60087]]

by compressors on board the source vessel. In addition to the 
operations of the airgun array, a multibeam 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.
    The Seward Johnson will have four deployments of OBSs, prior to the 
time when the Maurice Ewing conducts airgun operations in that area. 
After each line is shot, the Seward Johnson will retrieve the OBSs, 
download the data, and refurbish the units before redeploying the OBSs 
along the next line that will be shot. During the Southeast Caribbean 
cruise, there will be four deployments of OBSs, one deployment along 
each of the OBS lines. OBSs will also be deployed at two other 
locations near each line to fill data gaps between islands.
    In addition, the ocean floor will be mapped with an Atlas 
Hydrosweep DS-2 multibeam 15.5-kHz bathymetric sonar, and a 3.5-kHz 
sub-bottom profiler will also be operated along with the multibeam 
sonar. Both of these sound sources will be operated simultaneously with 
the airgun array. For more information regarding the Atlas Hydrosweep 
DS-2 multibeam bathymetric sonar, please refer to previous Federal 
Register Notices (68 FR 44291, July 28, 2003, and 68 FR 17773, April 
11, 2003).
    During the airgun operations, the vessel will travel at 7.4-9.3 km/
hr (4-5 knots), and seismic pulses will be emitted at intervals of 60-
90 sec (OBS lines) and approximately 20 sec (MCS 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 reverberation from 
previous shot noise during OBS data acquisition, and the exact spacing 
will depend on water depth. The 20-airgun array will include airguns 
ranging in chamber volume from 80 to 850 in3. These airguns will be 
spaced in an approximate rectangle of dimensions of 35 m (115 ft) 
across track by 9 m (30 ft) along track.
    Along the selected lines, the OBSs will be positioned by the Seward 
Johnson prior to the time when the Maurice Ewing conducts airgun 
operations in that area. After each line is shot, the Seward Johnson 
will retrieve the OBSs, download the data, and refurbish the units 
before redeploying the OBSs along the next line that will be shot. 
During the Southeast Caribbean cruse, there will be four deployments of 
OBSs, one deployment along each of the OBS lines. OBSs will also be 
deployed at two other locations near each line to fill data gaps 
between islands.
    When airgun operations with the 20-gun array commence after a 
period without airgun operations, the number of guns firing will be 
increased gradually (``ramped up,'' also described as a ``soft 
start''). Operations will begin with the smallest gun in the array (80 
in\3\). Guns will be added in sequence such that the source level of 
the array will increase in steps not exceeding 6 dB per 5-min period 
over a total duration of approximately 25 minutes. Throughout the ramp-
up procedure, the safety zone for the full 20-gun array will be 
maintained. Given the presence of the streamer and airgun array behind 
the vessel, the turning rate of the vessel with trailing streamer and 
array is no more than five degrees per minute, limiting the 
maneuverability of the vessel during operations.
    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 multibeam 
15.5-kHz bathymetric sonar, and a 3.5-kHz sub-bottom profiler will also 
be operated along with the multibeam sonar. These sound sources are 
commonly operated from the Maurice Ewing simultaneous with the airgun 
array.
    The Atlas Hydrosweep is mounted on the hull of the Maurice Ewing, 
and it operates in three modes, depending on the water depth. There is 
one shallow water mode and there are two deep-water modes: an Omni mode 
and a Rotational Directional Transmission mode (RDT). When water depth 
is less than 400 m (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 
athwartship. The beamwidth is measured to the -3 dB point, as is 
usually quoted for sonars. 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 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 and overall cross-track angular extent of about 140 
degrees, with small gaps between the pulses for successive 30-degree 
segments. The total during of the ``ping,'' including all five 
successive segments, varies with water depth, but is 1 millisec in 
water depths less than 500 m (1640.5 ft) and 10 millisec in the deepest 
water. For each segment, ``ping'' duration is 1/5th of these values or 
2/5th for a receiver in the overlap area ensonified by two beam 
segments. The ``ping'' interval during RDT operations depends on water 
depth and varies from once per second in less than 500 m (1640.5 ft) 
water depth to once per 15 seconds in the deepest water.
    The sub-bottom profiler is normally operated to provide information 
about the sedimentary features and the 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. 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.
    Additional information on the airgun arrays, bathymetric sonars, 
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 Southeast Caribbean Sea and its 
associated marine mammals can be found in a number of documents 
referenced in the LDEO application as well as in the LDEO application 
itself, and is not repeated here. In the Southeast Caribbean Sea and 
adjacent Atlantic Ocean, 30 marine mammal species are known to occur 
within the proposed study areas. Six species are listed as endangered 
under the U.S. Endangered Species Act (ESA): sperm, humpback, sei, fin, 
and blue whales, as well as West Indian manatees. These species 
included in this application are the sperm whale (Physeter 
macrocephalus), pygmy sperm whale (Kogia breviceps), dwarf sperm whale 
(Kogia sima), Cuvier's beaked whale (Ziphius cavirostris), Gervais' 
beaked whale (Mesoplodon europaeus), Blainville's beaked whale 
(Mesoplodon densirostris), rough-toothed dolphin (Steno bredanensis), 
tucuxi (Sotalia uviatilis), bottlenose dolphin (Tursiops truncatus), 
Pantropical spotted dolphin (Stenella attenuata), Atlantic spotted 
dolphin (Stenella frontalis), spinner dolphin (Stenella longirostris), 
clymene dolphin (Stenella clymene), striped dolphin (Stenella 
coeruleoalba), long-beaked common dolphin (Delphinus capensis), 
Fraser's dolphin

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(Lagenodelphis hosei), Risso's dolphin (Grampus griseus), melon-headed 
whale (Peponocephala electra), pygmy killer whale (Feresa attenuata), 
false killer whale (Pseudorca crassidens), killer whale (Orcinus orca), 
short-finned pilot whale (Globicephala macrorhynchus), humpback whale 
(Megaptera novaeangliae), minke whale (Balaenoptera acutorostrata), 
Bryde's whale (Balaenoptera edeni), sei whale (Balaenoptera borealis), 
fin whale (Balaenoptera physalus), and blue whale (Balaenoptera 
musculus). Also, one species of pinniped could potentially be 
encountered during the proposed seismic surveys. This includes the 
hooded seal (Cystophora cristata). Additional information on most of 
these species is available at: http://www.nmfs.noaa.gov/prot_res/PR2/Stock_Assessment_Program/sars.html.

Potential Effects on Marine Mammals

    The sound pressure fields for the 20-gun arrays has been modeled by 
LDEO, in relation to distance and direction from the airguns. Table 1 
in the application (LDEO Caribbean 2003) shows the distances from the 
arrays where sound levels of [gteqt]190, 180, 170, and 160 dB re 1 
microPa (rms) are predicted to be received:

----------------------------------------------------------------------------------------------------------------
                                                                 Predicted RMS Radii in meters/ft
                   Airgun Array                  ---------------------------------------------------------------
                                                      190 dB          180 dB          170 dB          160 dB
----------------------------------------------------------------------------------------------------------------
20 airguns......................................         275/902        900/2953       2600/8531     9000/29,529
----------------------------------------------------------------------------------------------------------------

    The rms (root-mean-squared) pressure is an average over the pulse 
duration. The rms level of a seismic pulse is typically about 10 dB 
less than its peak level (Greene 1997; McCauley et al. 1998, 2000a). 
The safety radii will be verified prior to the Southeast Caribbean 
cruise, using data from an acoustical measurement study in deep water 
within the Gulf of Mexico, which took place from 27 May to 3 June 2003. 
The data will either confirm or be used to refine the safety radii to 
be used during this and future LDEO seismic studies.
    Previous applications from LDEO have described similar actions. 
Past Federal Register notices for LDEO include July 28, 2003 (68 FR 
44291), August 26, 2003 (68 FR 51240), September 12, 2003 (68 FR 
53714), and September 17, 2003 (68 FR 54421). The Federal Register 
notice on April 14, 2003 (68 FR 17909) describes, in detail, the 
characteristics of the Ewing's acoustic sources and, in general, the 
anticipated effects on marine mammals including masking, disturbance, 
and potential hearing impairment and other physical effects. Possible 
effects of the sub-bottom profiler have been used in the projects 
described in the above notices. The LDEO Southeast Caribbean 
application also provides information on what is known about the 
effects on marine mammals of the types of seismic operations planned by 
LDEO.

Possible Effects of the Mid-Frequency Sonar Signals

    A multibeam bathymetric sonar (Atlas Hydrosweep DS-2, 15.5-kHz) 
will be operated from a source vessel at some times during the planned 
study. Sounds from the multibeam sonar are very short pulses, occurring 
for 1-10 msec once every 1 to 15 sec, depending on water depth. Most of 
the energy in the sound pulses emitted by this multibeam sonar is at 
high frequencies, centered at 15.5 kHz. The beam is narrow (2.67[deg]) 
in fore-aft extent, and wide (140[deg]) in the cross-track angles. A 
marine mammal at depth near the trackline would be in the main beam for 
only one or two of the five segments. Further information on mid-
frequency sonar can be found in the application or in a previous 
Federal Register notice 68 FR 17909 (April 14, 2003).

Possible Effects of the Sub-bottom Profiler Signals

    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. 
Further information on the sub-bottom profiler can be found in the 
application as well as in a previous Federal Register notice (68 FR 
44291, July 28, 2003).

Estimates of Take by Harassment for the Southeast Caribbean Sea Cruise

    All anticipated takes by harassment involve a temporary change in 
behavior. The mitigation measures to be applied will minimize the 
possibility of injurious takes. LDEO has calculated the ``best 
estimates'' for the numbers of animals that could be taken by level B 
harassment during the proposed seismic survey in the SE Caribbean Sea 
using data on marine mammal abundance from a previous survey region, as 
shown in the predicted RMS radii table.
    These estimates are based on a consideration of the number of 
marine mammals that might be exposed to sound levels greater than 160 
dB, which is currently used as the criterion for the onset of level B 
harassment, by operations with the 20-gun array planned to be used for 
the project. The anticipated radius of influence of the multibeam sonar 
is less than that for the airgun array. It is assumed that any marine 
mammals close enough to be affected by the multibeam sonar would 
already be affected by the airguns. Therefore, no additional allowance 
is included for animals that might be affected by the multibeam sonar.
    Tables 4 and 5 in the application explain the corrected density 
estimates as well as the ``best estimate'' of the numbers of each 
species that would be exposed to seismic sounds greater than 160 dB.
    According to the tables, the percentages of delphinidae that might 
be exposed to sound levels greater than 160 dB range from zero to 4.4 
percent. Aside from the sperm whale, the physeterida and ziphiidae 
exposure percentages are zero. The percent of sperm whales that might 
be exposed is 0.4 percent. Except for the humpback and blue whales, the 
mysticetes and pinnipeds percent of exposure is zero. It is estimated 
that 1.7 percent of humpback whales and 1.0 percent of blue whales 
could be exposed to sound levels greater than 160 dB. The ``best 
estimate'' of the numbers of common, bottlenose, Atlantic spotted, and 
pantropical spotted dolphins that might be harassed (exposed to levels 
greater than 160 dB) are 1.9 percent, 4.4 percent, 2.6 percent, and 4.3 
percent, respectively.
    The 160 dB criterion is based on studies of baleen whales. 
Odontocete hearing at low frequencies is relatively insensitive and 
delphinids generally

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appear to be more tolerant of strong low-frequency sounds than are most 
baleen whales. As a result, significantly fewer odontocetes than 
estimated here are likely to be harassed by the proposed action.
    Pinnipeds are not expected to be encountered in the SE Caribbean 
Sea and so the ``best estimate'' of the number that might be affected 
is zero. Although unlikely, a more conservative estimate of a maximum 
of five pinnipeds (most likely hooded seals) might be affected by a 
portion of the proposed survey in the SE Caribbean Sea. For further 
information regarding the estimated takes, refer to the LDEO Caribbean 
2003 application.

Conclusions- Effects on Cetaceans

    Strong avoidance reactions by several species of mysticetes to 
seismic vessels have been observed at ranges up to 8 km (4.3 nm) and 
occasionally as far as 30 km (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. 
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. The ``best estimate'' is that 377 
humpback whales or about 1.7 percent of the North and South Atlantic 
populations will be exposed to sound levels greater than or equal to 
160 dB re 1 microPa (rms). Acevedo and Smultea (1995) provide evidence 
that the North and South Atlantic populations overlap in their 
wintering areas. Similarly, only 52 sperm whales or approximately 0.4 
percent of the North Atlantic sperm whale population would receive 
seismic sounds greater than or equal to 160 dB during the proposed 
survey in the SE Caribbean Sea.
    The numbers of odontocetes that may be harassed by the proposed 
activities are small relative to the population sizes. A maximum of 
2475, 2222, 1369, 867, and 564 common, bottlenose, Atlantic spotted, 
rough toothed, and pantropical spotted dolphins, respectively (the most 
abundant delphinids in the proposed survey area) are expected to be 
exposed to seismic sounds greater than or equal to 160 dB. This 
represents 1.9 to 4.4 percent of the North Atlantic populations of 
these species based on population estimates for these species. However, 
these dolphin species surveys have not been conducted for most of their 
range in the North Atlantic Ocean and adjacent waters. The true 
percentages of the populations that might be exposed to seismic sounds 
greater than or equal to 160 dB are much less than 1.9-4.4 percent. The 
population sizes and the 1.9 to 4.4 percent are based on a small 
fraction of their range and their actual population sizes are actually 
much larger. The true percentages of the populations that might be 
exposed to seismic sounds greater than 160 dB are therefore much less 
than 1.9 to 4.4 percent. In light of all of these factors, the 
potential takings by Level B harassment are expected to have no more 
than a negligible impact on the affected species or stocks.
    Mitigation measures such as controlled speed, course alteration, 
look-outs, non-pursuit, ramp-ups, and power-downs when marine mammals 
are seen within defined ranges (See Mitigation) should further reduce 
short-term reactions to disturbance, and minimize any effects on 
hearing sensitivity.

Conclusions- Effects on Pinnipeds

    Pinnipeds are not expected to be encountered during the proposed 
seismic survey in the SE Caribbean Sea. However, a more conservative 
estimate of a maximum of 5 pinnipeds may be affected by a portion of 
the proposed survey in the SE Caribbean Sea if they were encountered. 
If pinnipeds were encountered, the proposed seismic survey would have, 
at most, a short-term effect on their behavior and negligible impacts 
on the affected 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

    Vessel-based observers will monitor marine mammals in the vicinity 
of the arrays. LDEO proposes to power-down the airguns if marine 
mammals are observed within the proposed safety radii, which will be 
verified prior to the southeast Caribbean cruise, using data from an 
acoustical measurement study in the Gulf of Mexico which took place May 
27, 2003, through June 3, 2003. Also, LDEO proposes to use a ramp-up 
procedure when commencing operations using the 20-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 25 minutes. Refer to LDEO's 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 20-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 (20 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.
    The airguns comprising these arrays will be spread out 
horizontally, so that the energy from the arrays will be directed 
mostly downward. This directionality will result in reduced sound 
levels at any given horizontal distance than would be expected at that 
distance if the source were omnidirectional with the nominal source 
level.

Marine Mammal Monitoring

    Vessel-based observers will monitor marine mammals near the seismic 
source vessel during all daytime airgun operations and during any 
nighttime start-ups of the airguns. During daylight, vessel-based 
observers will watch for marine mammals near the seismic vessel during 
periods with shooting (including ramp-ups), and for 30 minutes prior to 
the planned start of airgun operations after an extended shut-down. 
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 powered-

[[Page 60090]]

down if marine mammals are observed in or about to enter the safety 
radii. If the airguns are ramped-up at night, two marine mammal 
observers will monitor marine mammals near the source vessel for 30 
minutes prior to ramp-up using night vision devices.

Proposed Safety Radii

    Received sound levels have been modeled for the 20-gun arrays. 
Based on the modeling, estimates of the 190-, 180-, 170- and 160-dB re 
1 microPa (rms) distances for these arrays have been provided in the 
application. Airgun operations will be powered-down (or shut-down) 
immediately when cetaceans or pinnipeds are seen within or about to 
enter the appropriate 180-dB (rms) or 190-dB (rms) safety radius, 
respectively. These 180- and 190-dB criteria are consistent with 
guidelines for onset of level A harassment of 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 Mid-Atlantic seismic 
surveys, provided that doing so will not compromise operational safety 
requirements: (1) Speed or course alteration; (2) power-down 
procedures; (3) shut-down procedures; and (4) ramp-up procedures.
    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.

Course Alteration

    If a marine mammal is detected outside the appropriate safety 
radius and, based on its position and the relative motion, is likely to 
enter the safety radius, the vessel's speed and/or direct course 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 safety radius, further mitigative actions 
will be taken, i.e., either further course alterations or shutdown of 
the airguns.

Power-down Procedures

    If a marine mammal is detected outside the safety radius but is 
likely to enter the safety radius, and if the vessel's course and/or 
speed cannot be changed to avoid having the marine mammal enter the 
safety radius, the airguns will be powered-down before the mammal is 
within the safety radius. Likewise, if a mammal is already within the 
safety zone when first detected, the airguns will be powered-down 
immediately. For the power-down procedure for the 20-gun array, one 80 
in\3\ airgun will be operated during the interruption of seismic 
survey. Airgun activity (after both power-down and shut-down 
procedures) will not resume until the marine mammal has cleared the 
safety zone. An animal will be considered to have cleared the safety 
zone if it is visually observed to have left the safety zone, or if it 
has not been seen within the zone for 15 min (small odontocetes, 
including delphinidae, and pinnipeds) or 30 min (mysticetes and large 
odontocetes, including sperm, pygmy sperm, dwarf sperm, and beaked 
whales).

Shut-down Procedures

    If a marine mammal is detected close to the airgun array during a 
power-down, modeled safety radii for a single gun will be maintained. 
If the 20-gun array is used, the single gun that will be firing is 80 
in3. Since no calibrations have been done to confirm the modeled safety 
radii for this single gun, conservative (1.5 times the safety radius) 
radii will be used: 54 m (177 ft) for cetaceans, and 20 m (66 ft) for 
pinnipeds. If a marine mammal is seen within the appropriate safety 
radius of the array when the air guns have already been powered-down, 
airgun operations will be shut-down.

Ramp-up Procedure

    A ``ramp-up'' procedure will be followed when the airgun arrays 
begin operating after a specified duration without airgun operations. 
Under normal operational conditions (vessel speed 4 knots, or 7.4 km/
hr), a ramp-up would be required after a power-down or shut-down period 
lasting about 8 minutes or longer if the Ewing was towing the 20-gun 
array. At 4 knots, the source vessel would travel 900 m (2953 ft) 
during an 8-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 10 minutes or longer. At towing speeds not exceeding 3 
knots, the source vessel would travel no more than 900 m (3117 ft) in 
10 minutes. Based on the same calculation, a ramp-up procedure would be 
required after a 6 minute period if the speed of the source vessel was 
5 knots.
    Ramp-up will not occur if the safety radius has not been visible 
for at least 30 min prior to the start of operations in either daylight 
or nighttime. If the safety radius has not been visible for that 30 
minute period (e.g., during darkness or fog), ramp-up will not commence 
unless one airgun has been maintained during the interruption of 
seismic activity.

Monitoring and Reporting

    LDEO proposes to conduct the following marine mammal monitoring of 
its 2003 SE Caribbean Sea seismic program.

Vessel-based Visual Monitoring

    At least two observers will be based aboard the vessel. At least 
one experienced marine mammal observer will be on duty aboard the 
seismic vessel, and observers will be appointed by LDEO with NMFS 
concurrence. 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 increase 
the proportion of the marine mammals present near the source vessel 
that are detected. LDEO bridge personnel additional to the dedicated 
marine mammal observers will also assist in detecting marine mammals 
and implementing mitigation requirements whenever possible (they will 
be given instruction on how to do so), especially during operations at 
night when designated observers will not be on duty.
    The observer(s) will watch for marine mammals from the highest 
practical vantage point on the vessel, which is either the bridge or 
the flying bridge. On the bridge of the Maurice Ewing, the observer's 
eye level will be 11 m (36 ft) above sea level, allowing for good 
visibility within a 210[deg] arc. If observers are station on the 
flying bridge, the eye level will be 14.4 m (47.2 ft) above sea level. 
The observer(s) systematically scan the area around the vessel with 
reticle binoculars (e.g., 7 X 50 Fujinon) and 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 (Leica LRF 1200 laser rangefinder 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

[[Page 60091]]

be powered-down immediately. The observer(s) will continue to maintain 
watch to determine when the animal is outside the safety radius. If the 
airguns are powered-down, observers 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 or until the specified intervals (15 or 30 min) have passed 
without a resighting.
    If ramp-up procedures must be performed at night, two observers 
will be on duty 30 minutes prior to the start of airgun operations and 
during the subsequent ramp-up procedures. Ramp-up procedures for the 
20-gun array will not commence at night unless the seismic source has 
been maintained.

Reporting

    A report will be submitted to NMFS within 90 days after the end of 
the cruise. The end of the Caribbean cruise is predicted to occur on 
approximately 21 February 2004. The report will describe the operations 
that were conducted and the marine mammals that were detected. The 
report 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, 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. LDEO has initiated consultation with the U.S. Fish and Wildlife 
Service on West Indian Manatees.

National Environmental Policy Act (NEPA)

    The NSF has prepared an EA for the Southeast Caribbean surveys. 
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 the 
seismic survey in the Southeast Caribbean Sea and Adjacent Atlantic 
Ocean, off the coast of Venezuela, 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 or stocks.
    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 
surveys in the Southeast Caribbean Sea and Adjacent Atlantic Ocean, off 
the coast of Venezuela, 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 species or 
stocks for subsistence uses.

Information Solicited

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

    Dated: October 14, 2003.
Donna Wieting,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 03-26549 Filed 10-20-03; 8:45 am]
BILLING CODE 3510-22-S