[Federal Register Volume 69, Number 86 (Tuesday, May 4, 2004)]
[Notices]
[Pages 24571-24585]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-9858]


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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 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 
Southeast Caribbean Sea and adjacent Atlantic Ocean has been issued to 
Lamont-Doherty Earth Observatory (LDEO).

DATES:  Effective from April 16, 2004, through April 15, 2005.

ADDRESSES:  A copy of the IHA and the application are available by 
writing to Mr. P. Michael Payne, Chief, Marine Mammal Conservation 
Division, Office of Protected Resources, NMFS, 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 and is also available at:
    http://www.nmfs.noaa.gov/prot_res/ PR2/Small--Take/smalltake--
info.htm[numsign]applications

FOR FURTHER INFORMATION CONTACT: Kimberly Skrupky, Office of Protected 
Resources, NMFS, (301) 713-2322, ext 163.

[[Page 24572]]


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 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. This survey work was 
originally scheduled to be conducted from January 11, 2004, through 
February 21, 2004, but has been rescheduled for 17 April through 28 
May, 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. 
Approximately 2,031 km (1,097 n.mi.) of the survey 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 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 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 seconds (OBS lines) and approximately 20 sec (MCS lines). The 20-
second spacing corresponds to a shot interval of about 50 m (164 ft). 
The 60-90-second 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 in\3\ (0.0013 to 0.014 
m\3\). 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.

[[Page 24573]]

    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 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.
    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\) (0.0013 m\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.
    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-second intervals followed by a 5-second pause.
    Additional information of the work proposed for 2004 is contained 
in the proposed authorization notice (68 FR 60086, October 21, 2003), 
and in the application and in the Final Caribbean Environmental 
Assessment for oceanographic surveys in the Southeast Caribbean Sea and 
adjacent Atlantic Ocean (LDEO, 2003) which are available upon request 
(see ADDRESSES).

Changes From the Proposed IHA

    The calibration study data from a 2003 Gulf of Mexico survey 
indicate that the size of the 180-dB isopleth is dependent on water 
depth. A safety radii of 900 m (2935 ft) from the array at water depths 
greater than 1000 m (3281 ft), was estimated in the application and 
proposed IHA. The calibration measurements have indicated that the 180-
dB isopleth for water depths between 100 and 1000 m (328 and 3281 ft) 
is 1350 m (4429 ft) and the isopleth for water depths less than 100 m 
(328 ft) is 3500 m (11483 ft). These new data modify the take estimates 
for marine mammals. Refer to the Estimates of Take in this Notice for 
the updated take estimates.
    In light of the new data, NMFS has imposed additional mitigation 
measures for this seismic survey. First, the size of the safety radius 
to be monitored will be based on water depths in addition to the array 
size. Second, in addition to visual observers, LDEO will use passive 
acoustic monitoring (PAM) whenever the vessel is operating in waters 
deep enough for the PAM hydrophone array to be towed. Third, LDEO will 
increase the number of biological observers from two to at least three, 
and 2 to three additional biologists will monitor the PAM system. An 
additional one to two observers will be in the Seward Johnson and a 
land-based crew will monitor the beaches on an opportunistic basis. 
Finally, LDEO will use Big Eyes binoculars to enable observers to 
detect marine mammals at greater distances from the vessel. See 
Mitigation for more information.
    NMFS has also determined that takes of pinnipeds are not likely to 
occur in the action area. Therefore, hooded seals are not included in 
this IHA.

Comments and Responses

    A notice of receipt of the LDEO SE Caribbean application and 
proposed IHA was published in the Federal Register on October 21, 2003 
(68 FR 60086). During the comment period, NMFS received comments from 
the Center for Biological Diversity (CBD) and from the Marine Mammal 
Commission (Commission).

MMPA Concerns

    Comment 1: The CBD believes NMFS has not demonstrated that the LDEO 
project will take only small numbers of marine mammals.
    Response: NMFS believes that the small numbers requirement has been 
satisfied. The U.S. District Court for the Northern District of 
California held in NRDC v. Evans (Civil No. C-02-3805-EDL) that NMFS' 
regulatory definition of ``small numbers'' improperly conflates it with 
the ``negligible impact'' definition. Even if that is the case, NMFS 
has made a separate determination that the takes of the affected marine 
mammal species or stocks will be small. For example, the species or 
stock most likely to be harassed during the seismic survey is the 
bottlenose dolphin, with a ``best estimate'' of 2491 animals out of an 
estimated population size of 50,092 (LDEO, 2003). Although this 
absolute number may arguably not be small, it represents an estimated 
5.0 percent of the affected population that might be subject to a 
short-term disturbance and is therefore relatively small. Marine 
mammals not are expected to be seriously injured or killed, and no 
effects on reproduction and/or survival are anticipated.

[[Page 24574]]

    Comment 2: The CBD takes issue with NMFS' proposed IHA Federal 
Register notice on the ground that it does not provide basic data on 
the estimated number and percent of all 28 species of marine mammals 
that are projected to be exposed to sound levels greater than 160 dB.
    Response: The Federal Register Notice at 68 FR 60088 summarized the 
information on the take percentage estimates in LDEO's application for 
all the marine mammal species in the proposed study area. There is no 
requirement that all information in an application be provided in the 
Federal Register notice. NMFS normally provides the information it 
believes necessary to facilitate public review of its preliminary 
assessment on the impact of the activity on marine mammals. The Federal 
Register notice recommends reviewers obtain a copy of the application, 
which contains more detailed information on stock abundance and levels 
of incidental take, if the reviewer wants greater detail. In this case, 
NMFS summarized the information on the principal species of marine 
mammals that might be affected by this seismic survey. It was 
unnecessary to provide take estimates for species that are either not 
likely to be found in the area or are in such low abundance at the time 
of the survey that their take levels are close to zero. In any case, 
NMFS is reprinting the complete table on marine mammal harassment take 
estimates in LDEO's application in this document.

Marine Mammal Impact Concerns

    Comment 3: Noting that the surveys will take place not only in 
waters greater than 1,000 m (3281 ft) deep, but also in waters ranging 
from 100-1,000 m (328-3281 ft) and shallow water less than 100 m (328 
ft) deep, the CBD asserts that the Federal Register Notice for the 
proposed IHA does not adequately analyze the difference the depth of 
water has on the survey impacts to marine mammals or how a safety radii 
or other mitigation measures will be implemented in such waters.
    Response: The LDEO application describes how seismic sounds can be 
received in the ocean. Seismic sound received at any given point will 
arrive via a direct path, and often indirect paths that include 
reflection from the sea surface and bottom, and often segments through 
the bottom sediments. Sound propagating via indirect paths travel 
longer distances and often arrive later than sounds arriving via a 
direct path. These variations in travel time have the effect of 
lengthening the duration of the received pulse. Received levels of low-
frequency underwater sounds diminish close to the surface because of 
pressure-release and interference phenomena that occur at and near the 
surface (Urick 1983; Richardson et al. 1995). Paired measurements of 
received airgun sounds at depths of 3 m (9.8 ft) vs 9 m (29.5 ft) or 18 
m (59 ft) have shown that received levels are typically several 
decibels lower at 3 m (9.8 ft) (Greene and Richardson 1988). This 
provides additional protection to marine mammals while at the surface 
in the vicinity of the acoustic source.
    During a 2003 study in the northern Gulf of Mexico, LDEO obtained 
measurements of received sound levels as a function of distance from 
LDEO's airgun arrays for shallow water and deep water propagation. The 
calibration results from the 2003 Gulf of Mexico surveys were completed 
recently and are now available. As a result, depth-specific 180-dB 
distances will be used as safety radii, instead of the depth-
independent predicted ones with the precautionary 1.5 times factor, 
used during previous surveys. For the 20-gun array, the safety radius 
for 180 dB for water depths greater than 1000 m (3281 ft), as derived 
from the conservative acoustic model, is 900 m (2953 ft). For water 
depths between 100 and 1000 m (328 and 3281 ft), the safety radius is 
1350 m (4429 ft). For water depths less than 100 m (328 ft), the safety 
radius is 3500 m (11483 ft) for 180 dB. The shallow water measurements 
are based on empirical data from the Gulf of Mexico study, and are 
larger than previously predicted. This has resulted in a reanalysis of 
harassment take estimates, as explained later in this document.
    Comment 4: The CBD states that there is no mention of the 
compounded impact of the 20-airgun array's seismic output along with 
the two other acoustical data acquisition systems, the sonar and sub-
bottom profiler. CBD states that despite the fact that all of these 
sources will be operating, the Federal Register Notice provides no 
estimate of take from the sonar and profiler individually or from all 
three sources collectively and instead, it assumes 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. 
CBD believes that this explanation does not account for times when all 
three sources may not be operating simultaneously or provide any 
discussion of the enhanced impact of multiple acoustic sources when 
operating together.
    Response: As NMFS indicated in the Federal Register Notice of the 
proposed IHA, the multibeam has an anticipated radius of influence 
significantly less than that for the airgun array. NMFS further stated 
that 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 sonar. 
There is no enhanced impact of using the multibeam when operating it 
together with the airgun array. The sub-bottom profiler would not 
enhance impacts, since the radii of influence are smaller for the 
profiler than those of the airgun array.
    It is true that there are no estimates of take for times when the 
multibeam sonar and/or sub-bottom profiler are operated without 
airguns. This is because the 160-dB and 180-dB isopleths of the sub-
bottom profiler and multibeam are either small or the beams are very 
narrow, making the duration of the exposure and the potential for 
taking very small. As provided in the LDEO application, the 160-dB and 
180-dB radii in the horizontal direction, for the sub-bottom profiler, 
are estimated to be near 20 m (66 ft) and 8 m (26 ft), respectively. In 
the vertical direction, the 160-dB and 180-dB radii are 160 m (525 ft) 
and 16 m (52 ft) directly below the hull-mounted transducer. For the 
Hydrosweep there is minimal horizontal propagation, as these signals 
project downward and obliquely to the side at angles up to 
approximately 70 degrees from the vertical, but not horizontally. For 
the deep-water mode (see LDEO application or 68 FR 17909, April 14, 
2003 for description), below the ship these 160- and 180-dB zones are 
estimated to extend to 3200 m (10500 ft) and 610 m (2000 ft), 
respectively. However, the beam width of the Hydrosweep signal is only 
2.67 degrees fore and aft of the moving vessel, meaning that a marine 
mammal diving (not on the surface) could receive at most 1 to 2 signals 
from the Hydrosweep. Because NMFS treats harassment or injury from 
pulsed sound as a function of total energy received, the actual 
harassment or injury threshold for Hydrosweep signals (approximately 10 
millisec in duration) would be at a much higher dB level than that for 
longer duration pulses such as seismic or military sonar signals. As a 
result, NMFS believes that marine mammals are unlikely to be harassed 
or injured from the multibeam sonar or the Hydrosweep sonar due to the 
short

[[Page 24575]]

duration and only 1 to 2 pulses received.
    NMFS believes that other than to voluntarily ride the bow wave of 
the vessel (an indication that the animal is not annoyed), it is 
unlikely that a marine mammal would approach a moving vessel that 
close. If one did, the duration of exposure and of behavioral responses 
to these downward-directed sources would be very brief, and, NMFS 
believes, this brief behavioral response would not rise to the level of 
take.

Marine Mammal Habitat Concerns

    Comment 5: The CBD states that NMFS has failed to mention or 
require any exclusion zones to avoid seismic operations in coastal 
areas and key habitat for feeding, mating, breeding, and migration.
    Response: Impacts on marine mammal habitat were discussed in detail 
in the LDEO application and the NSF EA. During the period of the survey 
(April and May), marine mammals will be dispersed throughout the 
proposed study area in the southeast Caribbean Sea. No concentrations 
of marine mammals or marine mammal prey species are known to occur in 
the study area at that time of year. The airgun operations will not 
result in any permanent impact on habitats used by marine mammals or 
their food sources. The use of the OBS receivers may have a temporary 
disturbance to sediments and benthic organisms, but the area that may 
be disturbed is a small fraction of marine mammal habitat and the 
habitat of their prey species. Airguns are used as the energy source 
for the seismic surveys because it is believed that they do not kill 
fish, as occurred when explosives were used prior to the invention of 
the airgun. Injurious effects on fish would be limited to the area 
close to the seismic vessel. Presumably, ramp-up will also give fish 
schools an opportunity to move away from the sound source as the 
strength of the sound increases. Pending funding, NMFS plans to convene 
a panel of scientists in the near future to review the scientific 
information on the effects of seismic activities on fish and sea 
turtles.

Mitigation Concerns

    Comment 6: The Commission states that ``practicable,'' the word 
used in the MMPA, is not synonymous with the word ``practical,'' which 
seems to be the standard being used by NMFS in its responses. The 
Commission states, however, that the issue of practicability is a 
relevant consideration only if NMFS first determines that any taking 
incidental to the proposed activities will (a) be by harassment only, 
and (b) have a negligible impact on the affected species and stocks. 
The Commission's concerns regarding the effectiveness of the proposed 
monitoring programs, particularly nighttime operations, also apply to 
the NMFS determinations that the takings will be limited to harassment 
and that the impacts on affected species or stocks will be negligible.
    Response: NMFS uses the words ``practicable'' and ``practical'' to 
the extent that both terms have the same meaning. In both cases, NMFS 
considers whether a particular mitigation is capable of being effected, 
done, or executed; feasible. NMFS' consideration of practicability 
includes (among other relevant considerations) economic and 
technological feasibility (see 50 CFR 216.104(a)(11)). Congress 
recently elaborated on the meaning of the term in the case of Military 
Readiness Activities when it passed the National Defense Authorization 
Act of 2004. In determining practicability of mitigation for military 
readiness activities, NMFS explicitly is directed to consider 
``personal safety, practicality of implementation, and the impact of 
the effectiveness on military readiness activities.'' While the LDEO 
activity is not a military readiness activity, it is apparent that the 
term ``practicable'' may include considerations beyond simply whether a 
certain mitigation measure is technically capable of being implemented.
    As explained in the following responses to comments, NMFS believes 
that the mitigation and monitoring measures that have been imposed 
under the IHA are complete to the fullest extent practicable, and 
ensure that the takings will be limited to harassment and will result 
in a negligible impact on the affected species or stocks of marine 
mammals. The mitigation measures described in the proposed IHA notice 
have been enhanced subsequently by increased observer personnel and the 
recent addition of big-eye binoculars and passive acoustics to the 
ship's inventory. As mentioned in response to comment 3, the safety 
radii have also been re-calculated based on the results from the 
calibration study in the Gulf of Mexico in 2003 and will be applied to 
this seismic survey.
    Comment 7: The CBD states that NMFS' analysis of mitigation 
measures to ensure least practicable impact is flawed because its 
analysis of impacts is incomplete in that the safety radii have not 
been verified.
    Response: NMFS believes that the mitigation measures ensure the 
least practicable impacts. As discussed elsewhere in this document, the 
mitigation measures in the proposed IHA notice have been enhanced. As 
mentioned in response to comment 3, the safety radii have been re-
calculated based on the results from the calibration study in the Gulf 
of Mexico in 2003. These depth-specific safety radii will be applied to 
this seismic survey in lieu of the previously applied depth-independent 
1.5 X modeled safety radii.

Mitigation Concerns - Ramp-Up

    Comment 8: The Commission notes that, although NMFS has made 
several determinations based on an assumption that ramp-up of the sound 
source is an effective mitigation measure from protecting marine 
mammals from serious injury or mortality, empirical research has not 
been conducted to prove or disprove these assumptions with any degree 
of certainty. The Commission recommends that NMFS consult with LDEO 
regarding incorporating a marine mammal research component into future 
operations to develop data on the effectiveness of ramping up the sound 
source and on the avoidance of marine mammals once peak pressure levels 
have been attained.
    Response: While scientific research built around the question on 
whether ramp-up is effective has not been conducted, several studies on 
the effects of anthropogenic noise on marine mammals indicate that many 
marine mammals will move away from a sound source that they find 
annoying (e.g. Malme, 1984, Clark et al., 1999, Miller et al., 1999; 
others reviewed in Richardson et al., 1995). In particular, three 
species of baleen whales have been the subject of tests involving 
exposure to sounds from a single airgun, which is equivalent to the 
first stage of ramp-up. All three species were shown to move away at 
the onset of a single airgun operation (Malme et al., 1983-1986, BBN 
Reports 5366, 5586, 6265; Richardown et al., 1986 J. Acoust. Soc. Am.; 
McCauley et al., 1998, 2000 APPEA J.). From this research, it can be 
presumed that if a marine mammal finds a noise source annoying or 
disturbing, it will move away from the source prior to its becoming 
injurious, unless some other over-riding biological activity keeps the 
animal from vacating the area. This is the premise supporting NMFS' and 
others' belief that ramp-up is effective in preventing injury to marine 
mammals. In addition, observers and power-down/shut-down criteria 
provide for the protection of non-responding mammals: e.g., those that 
either do not hear the sounds because of a hearing impairment or 
because the

[[Page 24576]]

sounds are outside the hearing range of the species, or those 
individuals that do not react to the sounds because of behavioral or 
other physiological factors.
    A ramp-up study was first proposed to be conducted by the Minerals 
Management Service (MMS) in 1999 (HESS, 1999). While this study has not 
been funded to date, NMFS believes that a basic difficulty exists for 
testing ramp-up effectiveness without first establishing some mode of 
dose-response. As a result, prior to testing ramp-up effectiveness, 
this type of information is currently being obtained by the Sperm 
Whales Seismic Study (SWSS). NMFS believes that this information is a 
critical component for understanding marine mammal impacts from world-
wide operating seismic activities.
    In that regard, LDEO has indicated that it is committed to working 
with MMS and the offshore seismic industry during the Gulf of Mexico 
calibration research work in June 2005 to coordinate efforts to study 
the effects of ramp-up on marine mammals while continuing its 
calibration study of the airgun array onboard the Ewing. Additionally, 
LDEO is improving its efforts during all seismic research cruises to 
report on any behavioral observations or possible effects that are 
noted by the marine mammal observers specifically related to ramp-up 
periods.
    NMFS notes, however, that few marine mammals were sighted by 
observers during most LDEO cruises in 2003 (compare, for example LDEO 
observer reports for seismic in the Beaufort Sea (LGL, 1999), versus 
LDEO observer reports off Norway (LGL, 2003)). The low number of 
sightings during LDEO's 2003 cruises was attributable to the 
distribution and abundance of the mammals, and the time of year when 
LDEO's 2003 cruises were conducted, not to any limitations of the 
capabilities or effort by the marine mammal observers. The results of 
all marine mammal observations during LDEO's 2003 projects, including 
species identification and behavior are detailed in the reports that 
were submitted to NMFS after the conclusion of each cruise for which an 
IHA has been issued. Monitoring reports for four Ewing research cruises 
during 2003 (GOM; Hess Deep/Eastern Pacific; Norway; Mid-Atlantic) are 
now available (see ADDRESSES). The limited number of sightings that 
occur during many LDEO cruises mean that one can expect to obtain only 
a limited amount of information about reactions of marine mammals 
during the small number of ramp-ups that normally occur during a 
cruise.
    Comment 9: The Commission understands that LDEO has committed to 
not initiate ramp-up at night in the event of an unanticipated powering 
down of the array. This should reduce the likelihood of affecting 
marine mammals. The Commission appreciates LDEO's taking this measure.
    Response: LDEO agreed that it would not initiate ramp-up at night 
after a shut down (e.g., if LDEO had no guns firing when deploying OBS 
instruments). It was not LDEO's understanding or intention to expand 
that to preclude ramp-up after a nighttime power-down if monitoring 
could show that there was little likelihood that marine mammal(s) were 
within the safety radius. The power-down and shut-down procedures are 
explained in detail in the proposed IHA notice for this seismic survey 
(see 68 FR 60086, October 21,2003) and again in this document. However, 
the LDEO safety radius has subsequently been expanded considerably for 
work in shallow water (see discussion on results from the 2003 LDEO 
calibration study in the Gulf of Mexico elsewhere in this document). 
Therefore, NMFS is requiring under this IHA that LDEO will not initiate 
a ramp-up at night from a power down of an airgun array involving 
greater than 6 guns if the Ewing is operating in shallow water (<=100 
(328 ft)). In that situation, the safety radius would extend too large 
from the ship to effectively monitor visually at night. However LDEO 
can initiate ramp-up from a power-down situation when operating in 
water deeper than 100 m (328 ft) at night if the 180-dB radius is 
visible or the passive sonar has not recorded any mammalian 
vocalizations during the entire period of the power-down.

Mitigation- Passive Acoustics

    Comment 10: The Commission recommends that NMFS consider requiring 
the applicant to augment the proposed observer program with passive or 
active acoustic monitoring equipment. The Commission understands that 
LDEO has passive acoustic monitoring equipment onboard the Ewing and 
intends to use it on this and future cruises.
    Response: LDEO has committed to conducting passive acoustic 
monitoring during the SE Caribbean seismic cruise and elsewhere. 
Passive acoustic equipment was first used on the R/V Maurice Ewing 
during the 2003 SWSS study conducted in the Gulf of Mexico and was 
being evaluated by LDEO to determine whether it was practical to 
incorporate it into future seismic research cruises. The SEAMAP passive 
acoustic system has four hydrophones, which allow the SEAMAP system to 
derive the bearing toward the a vocalizing marine mammal. In order to 
operate the SEAMAP system, the marine mammal monitoring contingent 
onboard the Ewing will be increased to 5 biologists. An additional 2-3 
observers will be onboard the R/V Seward Johnson. This will provide the 
ability to both visually monitor the ocean and to use the SEAMAP system 
onboard the Ewing. Verification of acoustic contacts can then be 
attempted through visual observation by the marine mammal observers. 
However, passive acoustic monitoring by itself usually does not 
determine the distance that the vocalizing mammal might be from the 
seismic vessel. It can be used as a cue by the visual observers as to 
the presence of an animal and to its approximate bearing (with some 
ambiguity). However, at this time it is doubtful if passive acoustic 
monitoring can be used as a trigger to initiate power-down of the array 
(but see previous response for use prior to ramp-up). Perhaps with 
continued studies the relationship between a signal on a passive 
acoustic array and distance from the array can be determined with 
sufficient accuracy to be used for this purpose without complementary 
visual observations.

Mitigation-Observers

    Comment 11: The CBD states that the only proposed marine mammal 
detection method is visual surveillance by daytime observers.
    Response: The mitigation/monitoring protocols have been amended 
since the proposed IHA notice was published. There will be 2 U.S. and 1 
Venezuelan observer (from the Cetacean Research Center) onboard the 
Ewing (plus additional biologists for acoustic monitoring), and 2-3 
biological observers onboard the Seward Johnson. Since the monitoring 
periods on the Seward Johnson will not be continuous (essentially 
concentrating on the potential beaked whale habitats), the observer(s) 
will be assisted at these times by science personnel from the OBS group 
and the bridge watch personnel.
    In addition to shipboard personnel dedicated to visual and passive-
acoustic monitoring, other personnel deploying the land instrumentation 
will monitor the beaches in the vicinity of the survey lines where 
possible. However, some of the beaches in western Venezuela will not be 
easily accessible.
    Comment 12: The Commission notes that the effectiveness of 
mitigation

[[Page 24577]]

depends on the ability of the observers to detect all marine mammals 
that may be within the proposed safety zones. The Commission states 
that according to NMFS in a notice published on March 21, 2001 (66 FR 
1538), the estimated detection rate of marine mammals inside the 
proposed safety radii by visual observations (including both daytime 
and nighttime periods) has been revised from 5 percent to 9 percent. 
This rate increases to 18 percent for daytime only monitoring. The 
Commission states that these are average estimates for all species. 
Detection rates for larger species, such as sperm whales, would be 
considerably higher than for small species, like beaked whales. 
However, even with these revised rates, the Commission believes it is 
unlikely that the planned monitoring program will be very effective in 
detecting marine mammals within and entering the safety zones. As such, 
the Commission requests NMFS to provide additional explanation of its 
rationale for determining that marine mammals are unlikely to be 
exposed to sound levels above 180 dB for cetaceans or, if they are, 
that such exposures will not result in taking other than by harassment 
and that the effects of such taking will be negligible. In light of the 
fairly low power of the observer program to detect marine mammals 
within the safety zones, it seems NMFS is relying largely on marine 
mammal avoidance of harmful sound pressure levels for making its 
proposed findings.
    Response: The estimated effectiveness of visual observations was 
revised from 5 percent to 9 percent (67 FR 46712, July 16, 2002). That 
figure includes both daytime and nighttime periods of observation. The 
rate increases to 18 percent based only on daytime monitoring. The Navy 
based these efficacy ratings on the most difficult marine mammals to 
sight, such as harbor porpoise and Cuvier's beaked whales. That 
efficacy rating was highly conservative (see 67 FR 46712, July 16, 2002 
and Navy 2001). In that regard, NMFS shipboard marine mammal assessment 
surveys estimate a higher rate of efficacy for most species.
    There is a scientific methodology to estimate the probability of 
detecting marine mammals on the surface, as explained in detail in 
Buckland et al., (1993). This includes several components, including 
the probability that the mammal will be at the surface and potentially 
sightable while within visual range of the observers, the probability 
that an animal at the surface will in fact be detected, and the 
relationship between sighting probability and lateral distance from the 
trackline.
    A certain proportion of the population is presumed to be submerged 
at any given time and is therefore unavailable for detection. However, 
if the ship speed is slow, many of these animals would surface at some 
point while within visual range of observers aboard the approaching 
vessel. The speed of the Ewing and other seismic vessels while 
operating airguns will generally be less than 50 percent of the speed 
of the NOAA vessels conducting marine mammal line transect surveys.
    All LDEO estimates of potential numbers of animals take account of 
all these factors to the extent that available data allow. 
Detectability is a measure of the probability of detecting a marine 
mammal that is present on a vessel's trackline (i.e., g(0)). LDEO uses 
the most applicable detectability values as provided in Koski et al. 
(1998) whenever estimates of marine mammal detectability have not 
already been calculated. They compiled previously reported 
detectability information for various species and used data on 
surfacing/dive cycles to estimate detectability values for species or 
species groups of marine mammals for which there are no published 
detectability values. Thus the estimates of incidental take in LDEO's 
IHA application and the associated NSF EA are either the same (if 
detectability had already been taken into account) or higher than would 
be obtained by direct application of previously-reported density data.
    Any estimate that would be made would be specific to the region and 
the airgun array since the estimate would depend on (1) the distance to 
the 180-dB radius boundary, (2) the species that occur in the area and 
(3) the abundance for each species. If the estimate was being made for 
a small array (2 GI-guns) the estimate would essentially be a weighted 
average of the g(0) values based on the density of the species that 
would be encountered since all animals on the trackline are assumed to 
be sighted by the Transect Theory.
    However, when making the estimate for a large airgun array, one 
would need to consider the probability of detecting an animal at each 
lateral distance out to the 180-dB radius (and slightly beyond) and 
then averaging the probability over the whole area. One cannot assume 
that all animals within the estimated strip width (ESW) are seen even 
if they are on the surface. The number of sightings at various lateral 
distances (out to a truncation distance) are used to estimate the 
number missed within the ESW when calculating densities. The 
probability detection function is different for each species, but the 
function is most often calculated for combined groups of similar 
species. The actual probability detection functions are not published 
for most species, but some f(0) values are available. F(0) is a measure 
of the rate which sightability diminishes with increasing distance from 
the ship's trackline. So the problem is getting the actual 
probabilities of spotting animals at each lateral distance out to the 
180-dB radius.
    The assumed 180-dB distance for LDEO's standard 20-gun array 
operating in intermediate and deep waters is 1350 m (4429 ft) and 900 m 
(2953 ft), respectively. At-sea experience shows that the probability 
of detection at approximately 900 m lateral distance is likely to be 
near 0.5 - 0.6 but will vary somewhat among species. Thus the average 
probability of detection at all distances out to the 180-dB radius is 
likely to be approximately 0.7-0.9. If this is combined with the 
average g(0) which is probably approximately 0.9 (but needs to be 
calculated as described above and depends on species and group size) 
then an approximation of the proportion of animals present within the 
180-dB radius is about 0.6 to 0.8. This is a rough estimate and does 
not consider species-specific and some other inputs to the calculation 
but is likely a reasonable estimate of the overall average number based 
on doing the calculation. In addition, this may be an underestimate of 
the fraction detected because some animals may be detected farther away 
(though at a at a lower probability) and that is not considered in this 
calculation. Nothwithstanding the uncertainties and variability, it 
should be noted that this level of detectability is significantly 
higher than the value cited by the Commission.
    Another key factor in estimating the number of undetected mammals 
that might occur within the 180-dB radius is the fact that many marine 
mammals move away from an approaching seismic vessel (e.g., Richardson 
et al., 1995, Stone, 2003). The conventional estimates of the 
proportions present but missed by visual observations, as described in 
previous paragraphs, will overestimate (sometimes by very large 
factors) the numbers of mammals that might be exposed to high levels of 
sound near the ship. This is an important consideration in assessing 
possible exposures to high-level sound, especially for the more 
responsive species, notably some if not all baleen whales, beaked 
whales, and harbor porpoises. There is also some degree of

[[Page 24578]]

avoidance by a variety of other odontocetes (Stone 2003). In order to 
derive unbiased estimates of numbers that might be exposed to greater 
than 180 or 190 dB, density-based estimates that include allowance for 
g(0) and f(0) would need further adjustment to allow for an ``avoidance 
probability'' factor. Such factors are not generally available. They 
would depend on species and circumstances, and for some species would, 
if applied, result in a large decrease the estimates of the numbers 
that would be exposed to high-level sound.
    Finally, it must also be recalled that the 180-dB criterion for 
cetaceans was developed before any data were available on Temporary 
Threshold Shift (TTS), or its dependence on exposure duration, in any 
species of marine mammal. Those interim criteria were based largely on 
professional judgment and incorporating a substantial precautionary 
element. Some TTS data, including information about the relationship of 
TTS thresholds to exposure duration, have subsequently become available 
for odontocetes and pinnipeds (e.g. Kastak et al. 1999, 2000; Finneran 
et al. 2002, 2003; Nachtigall et al. 2003). Even now there are data on 
the potential for causing permanent hearing loss (permanent threshold 
shift or PTS), which is Level A harassment, for marine mammals. 
Richardson et al. (1995) noted, based on terrestrial mammal data, that 
the magnitude of TTS in marine mammals was expected to depend on the 
level and duration of noise exposure, among other considerations. 
Subsequent studies of TTS in marine mammals have confirmed this. For 
sound exposures at or somewhat above the TTS threshold, hearing 
sensitivity recovers rapidly after exposure to the noise ends.
    For toothed whales exposed to single short pulses, the TTS 
threshold appears to be, to a first approximation, a function of the 
energy content of the pulse (Finneran et al. 2002). Given the available 
data, the received level of a single seismic pulse might need to be on 
the order of 210 dB re 1 microPa (rms) (approx. 221 226 dB re 1 microPa 
(pk pk)) in order to produce brief, mild TTS. Exposure to several 
seismic pulses at received levels near 200 205 dB re 1 microPa (rms) 
might result in slight TTS in a small odontocete, assuming the TTS 
threshold is (to a first approximation) a function of the total 
received pulse energy (see Finneran et al. 2002). Seismic pulses with 
received levels of 200 205 dB re 1 microPa or more are usually 
restricted to a radius of no more than 100 m (328 ft) around (or below) 
a seismic vessel. There are no data, direct or indirect, on levels or 
properties of sound that are required to induce TTS in any baleen 
whale.
    A marine mammal within a radius of <=100 m (<=328 ft) around a 
typical array of operating airguns might be exposed to a few seismic 
pulses with sounds pressure levels [gteqt]205 dB, and possibly more 
pulses if the mammal moved with the seismic vessel and the mammal was 
not detected and the array was not powered-down. However, as noted 
above, most cetacean species tend to avoid operating airguns, although 
not all individuals do so. In addition, ramping up airgun arrays, which 
is standard operational protocol for LDEO, should allow cetaceans to 
move away from the seismic source and to avoid being exposed to the 
full acoustic output of the airgun array. It is unlikely that these 
cetaceans would be exposed to airgun pulses at a sufficiently high 
level for a sufficiently long period to cause more than mild TTS, given 
the relative movement of the vessel and the marine mammal. TTS would be 
more likely in any odontocetes that bow-ride or otherwise linger near 
the airguns. Bow-riding odontocetes would be at or above the surface, 
and thus not exposed to strong sound pulses given the pressure-release 
effect at the surface. However, bow-riding animals generally dive below 
the surface intermittently. If they did so while bow-riding near 
airguns, they would be exposed to strong sound pulses, possibly 
repeatedly. If some cetaceans did incur TTS through exposure to airgun 
sounds, this would very likely be a temporary and reversible 
phenomenon.
    For these reasons (small impact zone, avoidance of appraching ship 
by many marine mammals, precautionary nature of the 180-dB criteria, 
mitigation/monitoring protocols), NMFS has determined that LDEO's 
activity is likely to have no more than a negligible impact on affected 
marine mammal stocks.

Mitigation-Prohibition of Night-time Seismic Operations

    Comment 13: The CBD states that although bridge personnel will keep 
watch at night, night-time detection rates of marine mammals are 
probably very low. There is no discussion of why night-time operations 
are considered necessary, why experienced marine mammal observers will 
not be on duty during night-time hours, how effective any observation 
efforts are expected to be, or why alternative means of ensuring that 
the required monitoring program is likely to detect most marine mammals 
in or near the safety zones are not identified and required. The 
Commission questions whether night-time seismic operations should be 
authorized at all.
    Response: NMFS agrees that the effectiveness of night-time visual 
monitoring is limited. However, as mentioned in previous authorization 
notices, LDEO believes that night-time operations are necessary due to 
cost considerations. The daily cost to the Federal Government to 
operate vessels such as Ewing and the Seward Johnson is approximately 
$33,000 to $35,000/day for each vessel (Ljunngren, pers. comm. May 28, 
2003). If the vessels were prohibited from operating during night-time, 
it is possible that each trip would require an additional 3 to 5 days 
to complete the work, or up to $175,000 more per vessel per cruise, 
depending on average daylight at the time of work.
    If a seismic survey vessel is limited to daylight seismic 
operations (12-13 hours during April/May at this location), efficiency 
would be much reduced. Without commenting specifically on how that 
would affect the present project, for seismic operators in general, a 
daylight-only requirement would be expected to result in one or more of 
the following outcomes: cancellation of potentially valuable seismic 
surveys; reduction in the total number of seismic cruises annually due 
to longer cruise durations; a need for additional vessels to conduct 
the seismic operations; or work conducted by non-U.S. operators or non-
U.S. vessels when in waters not subject to U.S. law.
    NMFS final IHA requires mitigation measures including the use of 
passive acoustic monitoring to improve the detection of marine mammals 
by indicating to the visuals observers when an animal is potentially 
near and prompting a shut-down when necessary. The passive acoustic 
monitoring system will be deployed whenever the water depth is deep 
enough to effectively operate the system.
    Trained marine mammal observers using night vision devices (NVDs) 
will be on watch during periods prior to and during ramp-up from a 
power-down situation at night. They will also be on watch at other 
periods during the night, particularly if marine mammals are sighted in 
the seismic area during the day. In addition, NMFS is requiring that, 
if marine mammals are detected during daylight hours, the passive 
acoustic monitoring will need to continue to be operated throughout the 
succeeding night. LDEO is currently developing the protocols on how 
best to utilize passive acoustic monitoring to protect marine mammals.

[[Page 24579]]

    At other times during the night, observers will be available, but 
it is not necessary or very effective for them to be on watch 
constantly. For reasons discussed in the previous response, marine 
mammals are unlikely to be seriously injured or killed by the noise 
from approaching seismic arrays. Thus, limiting seismic shooting to 
only daylight hours is unnecessary and unlikely to result in less level 
B harassment to marine mammals than would conducting 24-hour survey 
operations.
    Because of the need to keep a vessel at-speed in order to 
successfully tow the hydrophone streamers, the vessel would need to be 
underway throughout the night whether or not the airguns are fired at 
night. Additional down-time can be anticipated each day as the vessel 
maneuvers all night to come back to the shut-down location 30 minutes 
after daylight. This is unlikely to be successful very often and will 
likely result in additional time needed for surveys to be completed.
    In reviewing LDEO's report for the Hess Deep (Smultea and Holst 
2003), it is apparent that few marine mammals would have been exposed 
to sound levels  180-dB (rms) even if there had been no 
visual observations or power-downs. In the Hess Deep study for example, 
only a single whale (probably a beaked whale) was sighted near the 
outer perimeter of the safety zone.
    Recently, LDEO completed two tests of the effectiveness of using 
NVDs (Smultea and Holst 2003, Appendix C; Holst 2004, Appendix B). 
Results of those tests indicated that the Night Quest NQ220 NVD is 
effective at least to 150 to 200 m (492 to 656 ft) away under certain 
conditions. That type of NVD is not effective at the much larger 180-dB 
radii applicable when a large array of airguns is in use. However, as 
noted in response to comment 12, it is the smaller zone where the 
received level is well about 180 dB where detection of any marine 
mammals that are present would be of particular importance. The 205-dB 
zone, within which TTS might occur, is likely to be approximately 100 m 
(328 ft) in radius. That is sufficiently within the range of the NVDs 
to allow some chance of detecting marine mammals visually within the 
area of potential TTS during ramp-up. Furthermore, a substantial 
proportion of the marine mammals that might be within that distance 
would be expected to move away either during ramp-up or, if the airguns 
were already operating, as the vessel approaches.
    Taking into consideration the additional costs of prohibiting 
night-time operations and the likely low impact of the activity (given 
the required mitigation and monitoring), NMFS has determined that the 
IHA's requirements will ensure that the activity will have the least 
practicable impact on the affected species or stocks for the following 
reasons. (1) Marine mammals will have sufficient notice of a vessel 
approaching with operating seismic airguns (at least one hour in 
advance), thereby giving them an opportunity to avoid the approaching 
array. (2) If ramp-up is required after a power-down, at least two 
marine mammal observers will be required to monitor the safety radius 
using NVDs, when necessary to improve vision, for 30 minutes before 
ramp-up begins and verify that no marine mammals are in or approaching 
the safety radius. (3) Ramp-up may not begin unless the entire 180-dB 
safety radius is visible (i.e., no ramp-up can begin in heavy fog or 
high sea states) and ramp-up may occur at night only if one airgun with 
a sound pressure level of at least 160 dB has been maintained during 
interruption of seismic activity. Therefore, the 20-gun array will not 
be ramped-up from a shut-down at night.

Monitoring Concerns

    Comment 14: The Commission notes that its comments on previous 
proposed IHAs have questioned whether monitoring beginning 30 minutes 
prior to the start-up of airgun operations is sufficient to detect 
marine mammals within or near the safety zones. NMFS has concluded that 
30 minutes should be sufficient. In making this conclusion the 
Commission quotes NMFS as noting that ``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.'' The Commission states that given 
a greater than 80 percent likelihood that large and small cetaceans 
will not be observed within the safety zones, even under the best of 
conditions using experienced observers, this conclusion is not well 
supported.
    Response: The 30-minute observation period does not include the 
ramp-up period. Under the IHA, ramp-up must not proceed faster than 6 
db per 5 minutes, which would add an additional monitoring period of 25 
minutes. The total observation period, therefore, would be 
approximately 55 minutes prior to start of seismic operations at full 
power of the array. This is sufficient time for an observer to ensure, 
to the greatest extent practicable, that no marine mammals are within 
the moving safety zone. At a towing speed of 4 to 5 knots (7.4 to 9.3 
km/hr), the vessel would be close to 4 to 5 nm (7.4 to 9.3 km) from the 
location that observations began by the time seismic surveys would 
begin. Since the safety zone is also moving forward at the same speed 
as the vessel, marine mammals would also be alerted to the ship's 
presence long before a marine mammal came within view of the 
observer(s). Therefore, the period of approximately 55 to 60 minutes is 
judged by NMFS to be adequate to spot marine mammals prior to the 
seismic array reaching full operating power.
    See also the response to Comment 12. During daytime, the 
probability of missing mammals present within the safety radius is 
lower than the 80 percent figure mentioned above, and the natural 
avoidance responses of many marine mammals are a further mitigating 
factor.
    Comment 15: Using Cuvier's beaked whale as an example, the 
Commission states that although an experienced observer with binoculars 
might be able to sight such species at one mile (1.61 km) in very good 
weather and calm sea conditions, it is highly unlikely that bridge 
personnel, tasked with other duties, could do so. NMFS scientists 
estimate that skilled observers searching with 25X binoculars in calm 
seas can visually detect only 23 percent of the animals passing 
directly under ships and that essentially none can be detected beyond 3 
km (1.6 nm). In light of these considerations, NMFS needs to provide 
further explanation as to why it believes that 30 minutes of 
monitoring, prior to activation of the airguns at night will be 
adequate to detect large whales and other marine mammals that will be 
in the vicinity of the operations.
    Response: Please see the response to Comment 14 regarding the 
length of the monitoring period. The probability of detecting a 
Cuvier's beaked whale is 0.23. This detectability rate is calculated 
for vessels traveling at about 15 knots, not 5 to 6 knots of the Ewing, 
so it is likely to be higher for observers on the Ewing. Statements 
have been made in the past that little information is available on 
beaked whales because they avoid survey vessels. One can presume 
therefore, that observers onboard a vessel conducting seismic 
operations are unlikely to see beaked whales not only because they are 
cryptic but also because they would see or hear the vessel and leave 
the area. This avoidance behavior may be similar to that of the bowhead 
whales migrating in the Beaufort Sea during seismic operations. Most 
migrating bowheads will avoid the seismic operations area by at least 
20 km (10.8 nm). We presume that beaked whales will similarly avoid

[[Page 24580]]

sources of anthropogenic noise, provided they are afforded sufficient 
notice of the activity through a gradual increase in noise levels 
rather than receiving a sudden, loud sound that might inflict a panic 
reaction or perhaps serious injury.
    In regard to the Commission's statement on other duties, the night-
time watch is conducted by the bridge-lookout watch which is comprised 
of the following personnel and schedules: (1) Mate on Watch. Other 
duties include weather observations, half hour navigation updates, 
radar monitoring and radio watch; and (2) Bridge Watch assignments; 
bridge watch persons are assigned only as bridge watch personnel. These 
individuals have no other assignments as the bridge is blacked out 
(except chart room). Bridge watch assignments are as follows: (1) 1600-
2000 hrs: One able-bodied (AB) seaman is on watch at all times (except 
30-minute meal time when watch is relieved by Master-but this is 
usually during daylight hours when biological observers would be 
working anyway); (2) 2000 to 2400 & 0000 to 0400 hrs: One able-bodied 
seaman and one ordinary seaman on Port and Starboard bridge watch. This 
is their only duty except that AB makes rounds once per watch (about 30 
minutes); (3) 0400 to 0800 hrs. One AB seaman on watch. Again there is 
relief for breakfast but by then the daytime marine mammal observers 
are on watch.
    Finally, NMFS notes that the monitoring methods employed on the 
Ewing are standard methods used onboard vessels for conducting marine 
mammal abundance surveys and under IHA's. NMFS is especially interested 
in exploring with the Commission the potential for alternative, 
practical, monitoring methodology for use in waters too far from shore-
side support facilities.
    Comment 16: The Commission continues to have concerns that, without 
effective monitoring to detect when marine mammals are in or may be 
entering the safety zones, the chances that animals will be exposed to 
sounds capable of causing serious injury or death increases 
considerably. Therefore, NMFS, before issuing the IHA, particularly for 
night-time operations, needs to explain the basis for determining that, 
even in the absence of effective measures to detect all marine mammals 
whith the safety zones, taking will be by harassment only and will have 
a negligible impact on the affected species and stocks.
    Response: Refer to responses to comments 12 and 13. Since few 
marine mammals are sighted in daylight hours by trained observers 
within the 180-dB isopleth, NMFS believes that few marine mammals will 
approach a vessel at night while the seismic arrays are on. The 
combination of all mitigation and monitoring measures previously 
discussed, along with the avoidance responses of many mammals, ensure 
that takings, incidental to this activity, either in daylight or 
nighttime will result in no more than a negligible impact on affected 
species and stocks of marine mammals and will result in the least 
practicable impact on these affected species or stocks.
    Comment 17: The Commission believes that more justification is 
needed for the conclusion that marine mammals are not likely to be 
harmed by exposure to sound during the survey than the lack of evidence 
that this occurred during previous operations. This is particularly 
important because some of the planned survey will be conducted in 
relatively shallow waters, near islands and channels, in habitat that 
shares many characteristics with areas where strandings and mortalities 
of beaked whales occurred coincident with other seismic operations. 
Even where the topography of the areas differ, the Commission does not 
believe that a lack of evidence of injured or dead marine mammals 
following other surveys necessarily means that no marine mammals have 
been harmed. It could also reflect the inadequacy of post-survey 
monitoring activities. Accordingly, the Commission again recommends 
that post-survey monitoring be required as part of any small-take 
authorization to the applicant for the proposed survey.
    Response: NMFS concurs that some form of post-survey monitoring 
should be conducted when and where practicable. NMFS will require, 
whenever possible, additional monitoring for marine mammal impacts 
after a research cruise, especially when that cruise takes place in 
beaked whale habitat. If post-survey shipboard monitoring is not 
practicable, applicants may be required to conduct independent 
scientific research to verify that the taking is negligible and at the 
lowest level practicable (see Hoffman and Swartz, 1991). This was 
recommended by Congress when it passed the MMPA Amendments of 1981 
which implemented this program.
    However, during the tens of thousands of line miles run annually by 
the seismic industry in the Gulf of Mexico, seismic airguns were not 
suspected of causing any marine mammals to strand prior to the 2002 
Gulf of California beaked whale stranding event while the Ewing was 
engaged in a seismic survey there. Scientifically the link between the 
Ewing and the Gulf of California stranding is extremely tenuous (due to 
the distance between the stranded animals and the Ewing), and it is 
likely that no evidence will be available to determine whether impulse 
or acoustic trauma played a role in those strandings because the 
tissues were too decomposed to properly evaluate and the heads were not 
retrieved.
    For the SE Caribbean research expedition, LDEO will conduct post-
survey monitoring by sub-sampling for marine mammals along the Ewing's 
MCS/OBS seismic lines by the R/V Seward Johnson's conducting 
observations for marine mammals along various sections of the seismic 
lines. LDEO will use subsampling methodology because the R/V Seward 
Johnson will not be able to follow behind the R/V Maurice Ewing on all 
coincident MCS/OBS profiles (each profile takes an average of 40 hours 
to shoot) because of vessel commitments elsewhere. However, the LDEO 
vessels will be transiting each transect profile 3 times - once before 
shooting while they deploy instruments, once during shooting as they 
transit back to the start of the profile, and again after shooting as 
the vessels pick up the instruments. Therefore, post-survey monitoring 
will be achieved by observer effort along each of the profiles prior 
to, during, and following the seismic activity. This will provide the 
biological observers with several opportunities to determine marine 
mammal distribution and abundance along the transit lane, conduct 
observational and acoustical monitoring and look for injured or dead 
marine mammals.
    In addition, LDEO has requested marine mammal volunteers from the 
Centro de Investigacion de la Biodiversidad Tropical Biotropica in 
Venezuela to assist in marine mammal observations during transects by 
the R/V Seward Johnson II along these seismic lines. Shoreside, the 
Venezuelan and U.S. scientists who will monitor seismic instrumentation 
along an approximate landward extension of the MCS/OBS lines will also 
monitor the beaches during each of the MCS/OBS surveys and report any 
marine mammal stranding or unusual offshore activity prior to, during, 
and after each line survey.

IHA Concerns

    Comment 18: The Commission recommends that, because of the 
likelihood that not all marine mammals within or entering the safety 
zones will be detected, and therefore, may be

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exposed to high-intensity sounds, any authorization that is issued 
should explicitly require that the operations be suspended immediately 
if a dead or seriously injured animal is found in the vicinity of the 
operations, pending authorization to proceed or issuance of regulations 
authorizing such takes under section 101(a)(5)(A) of the MMPA.
    Response: All IHAs that are limited to taking by Level B harassment 
stipulate that the taking by serious injury or death of these species 
or the taking by harassment, injury or death of any other species of 
marine mammals is prohibited and may result in the modification, 
suspension or revocation of the IHA. Recent IHAs issued to LDEO for 
seismic operations onboard the Ewing contain a provision that ``if 
observations are made or credible reports are received that one or more 
marine mammals of any species are within the area of this activity in 
an injured or mortal state, or are indicating acute distress, the 
seismic airgun array will be immediately shut down and the Chief of the 
Marine Mammal Conservation Division or a staff member contacted.'' This 
requirement is also in the IHA issued for this activity.

Additional Concerns

    Comment 19: NMFS has not yet complied with its Endangered Species 
Act (ESA) duties, and thus may not issue a small take authorization for 
the LDEO project.
    Response: NMFS has completed consultation under section 7 of the 
ESA. NMFS issued a biological opinion regarding the effects of this 
action on ESA-listed species and critical habitat. That biological 
opinion concluded that this action is not likely to jeopardize the 
continued existence of listed species or result in the destruction or 
adverse modification of critical habitat.
    Comment 20: The CBD believes that in order for NMFS to comply with 
the National Environmental Policy Act (NEPA), it must demonstrate that 
it has fully analyzed the impacts of, alternatives to, and mitigation 
measures for the project prior to issuing an Incidental Harassment 
Authorization for the LDEO project. NMFS must assess the cumulative 
impacts of the project in conjunction with other actions on the 
environment.
    Response: NMFS closely follows NEPA regulations and NOAA 
Administrative Order 216-6 (Environmental Review Procedures for 
Implementing the National Environmental Policy Act, May 20, 1999) 
before making a determination on whether it will adopt another federal 
agency's NEPA document, or prepare its own. Critical to this 
determination is the quality of another agency's NEPA document, whether 
it fully addresses the action proposed by NMFS, and whether NMFS' 
proposed action is significant as defined in 40 CFR 1508.27 and NAO 
216-6, section 6.01. As noted in the proposed authorization notice (68 
FR 60086, October 21, 2003), an Environmental Assessment (EA) was 
prepared by the National Science Foundation (NSF) and released to the 
public by NMFS. That EA contained a complete description of the 
proposed action and identified alternatives to that action; a 
description of the affected environment; an assessment of impacts, 
including unavoidable impacts, indirect impacts and cumulative impacts; 
and the measures proposed to reduce impacts to the lowest level 
practicable. In accordance with NAO 216-6, NMFS has reviewed the 
information contained in NSF's EA and determined that, while it 
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, 
additional mitigation measures have been identified and are reflected 
in the final IHA and the NMFS Finding of No Significan Impact (FONSI). 
Therefore, preparation of an environmental impact statement on this 
action is not required. A copy of the NSF EA and FONSI are available 
upon request (see ADDRESSES).
    Comment 21: The Commission recognizes that the assumptions made by 
NMFS in issuing an IHA to LDEO are central to the use of acoustic 
arrays during night-time observations when observers cannot be used to 
monitor the occurrence of marine mammals. The use of the passive 
acoustics and the continued use of observer data during daylight hours 
and evaluation of that effort to determine that marine mammals do avoid 
the sound source during ramping up should provide the level of 
monitoring necessary to ensure that any potential takings will be 
negligible in their effect on marine mammal species and stocks in the 
survey area.
    Response: NMFS agrees with the Commission.
    Comment 22: While the Commission appreciates the costs and 
inconvenience associated with implementing some recommendations, 
section 101(a)(5)(D) of the MMPA requires that, even when taking by 
harassment would have a negligible impact on marine mammal species and 
stocks, an authorization (must) prescribe ``means of effecting the 
least practicable (Commission emphasis) impact on such species or stock 
or its habitat...'' Thus, additional justification is needed to explain 
why restricting operations to daylight hours, using additional 
monitoring techniques, such as passive acoustic devices, and requiring 
post-exposure surveys are not possible.
    Response: See response to Comment 6 and others for the response the 
this comment.

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, 28 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. The 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 (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). 
Additional information on most of these species is available at: http://www.nmfs.noaa.gov/prot_res/PR2/Stock_Assessment_Program/sars.html.

[[Page 24582]]

Potential Effects on Marine Mammals

    A discussion on potential impacts on marine mammals was provided in 
the Federal Register notice 68 FR 60086 (October 21, 2003) and in the 
LDEO application.

Mitigation

    The following mitigation measures are required for the subject 
seismic surveys, provided that they do not compromise operational 
safety requirements: (1) Speed and course alteration; (2) power-down 
and shut-down procedures; (3) ramp-up procedures; and (4) marine mammal 
and sea turtle monitoring in the vicinity of the arrays through 
observers and passive acoustic monitoring. These mitigation measures 
are further described here.
    These mitigation measures will incorporate use of the safety radii 
that have been established from the 2003 calibration study in the Gulf 
of Mexico. LDEO has modeled the sound pressure fields for the 20-gun 
array in relation to distance and direction from the airguns. The 
safety radii for 180 dB for water depths greater than 1000 m (3281 ft) 
is 900 m (2953 ft). For water depths between 100 and 1000 m (328 and 
3281 ft), the safety radii is 1350 m (4429 ft). For water depths less 
than 100 m (328 ft), the safety radii are 3500 m (11483 ft).
    The directional nature of the 20-airgun array to be used in this 
project is also an important mitigating factor. The airguns comprising 
these arrays will be spread out horizontally, so that the energy from 
the arrays will be directed mostly downward, 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.

Speed and Course Alteration

    If a marine mammal or sea turtle 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 and Shut-down Procedures

    Airgun operations will be powered-down (or shut-down) immediately 
when cetaceans or pinnipeds are seen within or about to enter the 
appropriate safety radius, based on the water depth. 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. If a marine 
mammal is seen within the appropriate safety radius of the array while 
the guns are powered-down, airgun operations will be shut-down. For the 
power-down procedure for the 20-gun array, one 80 in3 airgun will 
continue to be operated during the interruption of seismic survey. 
Airgun activity (after both power-down and shut-down procedures) will 
not resume until any marine mammal has cleared the safety radius. The 
mammal has cleared the safety radius if it is visually observed to have 
left the safety radius, or if it has not been seen within the zone for 
15 min (small odontocetes, pinnipeds) or a minimum of 30 min 
(mysticetes and large odontocetes, including sperm, pygmy sperm, dwarf 
sperm, beaked and bottlenose whales). These mitigation measures also 
apply in the case of sea turtles.

Ramp-up Procedure

    When airgun operations with the 20-gun array commence after a 
certain period (explained below) without airgun operations, the number 
of guns firing will be increased gradually, or ``ramped up'' (also 
described as a ``soft start''). Operations will begin with the smallest 
gun in the array (80 in3) (0.0013 m3). 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 monitored. 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, making 
the ramp-up and power-down procedures a necessary mitigation measure.
    The ``ramp-up'' procedure will be required under the following 
circumstances. 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, ramp-up will 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 will be required 
after a 6 minute period if the speed of the source vessel is 5 knots.
    Ramp-up will not occur if the safety radius has not been visible 
for at least 30 minutes 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 at least one airgun has been firing continuously during 
the interruption of seismic activity.

Marine Mammal Monitoring

    LDEO must have at least three visual observers and two passive 
acoustic monitors on board the vessels, and at least two must be 
experienced marine mammal observers that NMFS approves. In addition, 
there will be 2 to 3 observers on the Seward Johnson, who will be 
assisted by science personnel from the OBS group and the bridge watch 
personnel. These observers will monitor marine mammals and sea turtles 
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 and sea turtles 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.
    An observer must also be on watch part of the time, including the 
30-minute periods preceding startup of the airguns and during ramp-ups. 
Use of multiple observers will increase the likelihood that marine 
mammals near the source vessel are detected. LDEO bridge personnel will 
also assist in detecting marine mammals and implementing mitigation 
requirements

[[Page 24583]]

whenever possible (they will be given instruction on how to do so), 
especially during ongoing operations at night when the designated 
observers are not on duty.
    The observers will watch for marine mammals and sea turtles 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 arc. If observers are stationed on the 
flying bridge, the eye level will be 14.4 m (47.2 ft) above sea level. 
The observer(s) will systematically scan the area around the vessel 
with Big Eyes binoculars, reticle binoculars (e.g., 7 X 50 Fujinon) and 
with the naked eye during the daytime. Laser range-finding binoculars 
(Leica L.F. 1200 laser rangefinder or equivalent) will be available to 
assist with distance estimation. The observers will be used to 
determine when a marine mammal or sea turtle is in or near the safety 
radii so that the required mitigation measures, such as course 
alternation and power-down or shut-down, can be implemented. If the 
airguns are powered or shut down, observers will maintain watch to 
determine when the animal is outside the safety radius.
    Observers will not be on duty during ongoing seismic operations at 
night; bridge personnel will watch for marine mammals during this time 
and will call for the airguns to be powered-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 for marine 
mammals for 30 minutes prior to ramp-up and during the ramp-up using 
night vision equipment that will be available (ITT F500 Series 
Generation 3 binocular image intensifier or equivalent). All observer 
activity will be assisted by the passive acoustic monitoring system 
where its use is feasible.
    Additional personnel will be on land deploying the land 
instrumentation and will monitor the beaches in the vicinity. Some of 
the beaches in western Venezuela are not easily accessible, but the 
observers have agreed to monitor the beaches to the best of their 
abilities.

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 May 28, 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.

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.
    The ``best'' estimate of numbers of marine mammals that might be 
``taken'' by disturbance during LDEO's proposed seismic survey with a 
20-gun array in the SE Caribbean Sea is shown in the table below. Any 
marine mammal that is exposed to sound intensity 160 dB re 1 
micro-pa is assumed to be ``taken'' due to possible changes in 
behavior. Not all marine mammals will change their behavior when 
exposed to these sound levels, particularly odontocetes, and some may 
alter their behavior when levels are lower. Also, the densities assumed 
in this table might be considerably higher or considerably lower at the 
time of the proposed activity than the densities recorded during past 
surveys.
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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 in Arctic waters.
    Odontocetes reactions to seismic pulses, or at least those of 
dolphins, are expected to extend to lesser distances than are those of 
mysticetes. Odontocetes 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 8 
humpback whales, which is slightly greater than 0 percent of the North 
and South Atlantic populations, will be exposed to sound levels greater 
than or equal to 160 dB re 1 micro-pa (RMS). Achieved and Smultea 
(1995) provide evidence that the North and South Atlantic populations 
overlap in their wintering areas. Similarly, 59 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 their respective population sizes. A 
maximum of 2776, 2491, 1535, 972, and 633 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 2.1 to 5.0 percent of the North Atlantic populations of 
these species based on population estimates for these species. However, 
surveys have not been conducted for these species of dolphins 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 2.1 to 5.0 
percent. The population sizes and the 2.1 to 5.0 percent are based on a 
small fraction of their range and their actual population sizes are 
actually much larger. 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.

Determinations

    NMFS has 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 numbers of potential incidental harassment takes depend 
on the distribution and abundance of marine mammals in the vicinity of 
the survey activity, the numbers are 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 either do not occur or are 
limited in nature and scope.

Endangered Species Act (ESA)

    Under section 7 of the ESA, NMFS has completed a biological opinion 
on the effects of the seismic survey on ESA-listed species and critical 
habitat. NMFS concluded that these activities are not likely to 
jeopardize the continued existence of these species.

National Environmental Policy Act (NEPA)

    On September 11, 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 October 21, 2003 (68 FR 60086), NMFS noted that the NSF 
had prepared an EA for the SE Caribbean surveys and that this EA was 
available upon request. In accordance with 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. 
Therefore, based on this review and analysis, NMFS is adopting the NSF 
EA under 40 CFR 1506.3 in addition to the supplemental EA, and has 
issued a Finding of No Significant Impact (FONSI). The FONSI also takes 
into consideration additional mitigation measures in the IHA that are 
not in NSF's EA. A copy of the NSF EA and the NMFS FONSI for this 
activity are 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 surveys in the Southeast 
Caribbean Sea and adjacent Atlantic Ocean, off the coast of Venezuela 
to LDEO for a 1-year period, provided the mitigation, monitoring, and 
reporting requirements are undertaken.

    Dated: April 26, 2004.
Stephen L. Leathery,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 04-9858 Filed 5-3-04; 8:45 am]
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