[Federal Register Volume 72, Number 157 (Wednesday, August 15, 2007)]
[Notices]
[Pages 45744-45754]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-16013]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 050107H]


Incidental Takes of Marine Mammals During Specified Activities; 
Seismic Testing and Calibration in the Northern Gulf of Mexico

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

ACTION:  Notice; issuance of incidental harassment authorization.

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SUMMARY:  In accordance with the Marine Mammal Protection Act (MMPA) 
regulations, notification is hereby given that NMFS has issued an 
Incidental Harassment Authorization (IHA) to the Lamont-Doherty Earth 
Observatory (L-DEO) to take small numbers of marine mammals, by Level B 
Harassment only, incidental to conducting an acoustic calibration and 
seismic testing program in the northern Gulf of Mexico.

DATES: Effective from July 31, 2007 through July 30, 2008.

ADDRESSES:  A copy of the IHA, the application, and the associated 
Environmental Assessment (EA) and Supplemental EA are available by 
writing to Michael Payne, Chief, Permits, Conservation, and Education 
Division, Office of Protected Resources, National Marine Fisheries 
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, or by 
telephoning the contact listed here. A copy of the application 
containing a list of references used in this document may be obtained 
by writing to this address, by telephoning the contact listed here (FOR 
FURTHER INFORMATION CONTACT) or online at: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this notice may be viewed, 
by appointment, during regular business hours, at the aforementioned 
address.

FOR FURTHER INFORMATION CONTACT:  Jolie Harrison, Office of Protected 
Resources, NMFS, (301) 713-2289, ext 166.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified geographical region if certain findings are 
made and either regulations are issued or, if the taking is limited to 
harassment, a notice of a proposed authorization is provided to the 
public for review.
    Authorization shall be granted if NMFS finds that the taking will 
have a negligible impact on the species or stock(s), will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses, and that the permissible methods of 
taking and requirements pertaining to the mitigation, monitoring and 
reporting of such takings are set forth. NMFS has defined ``negligible 
impact'' in 50 CFR 216.103 as ''* * * an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the United States can apply for an authorization 
to incidentally take small numbers of marine mammals by harassment. 
Except with respect to certain activities not pertinent here, the MMPA 
defines ``harassment'' as:

    any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

    \Section 101(a)(5)(D) establishes a 45-day time limit for NMFS 
review of an application followed by a 30-day public notice and comment 
period on any proposed authorizations for the incidental harassment of 
marine mammals. Within 45 days of the close of the comment period, NMFS 
must either issue or deny issuance of the authorization.

Summary of Request

    On June 2, 2006, NMFS received an application from L-DEO for the 
taking, by Level B harassment, of several species of marine mammals 
incidental to conducting, with research funding from the National 
Science Foundation (NSF), an acoustic calibration and seismic testing 
program in the northern Gulf of Mexico in Fall, 2006. This project will 
be conducted with L-DEO's new seismic vessel, the R/V Marcus G Langseth 
(Langseth), which will deploy different configurations of airguns and a 
different bottom-mapping sonar than used previously by L-DEO. L-DEO 
requests that it be issued an IHA allowing Level B Harassment takes of 
marine mammals incidental to the planned seismic surveys in the Gulf of 
Mexico. A detailed description of the purpose of the calibration and 
testing program was outlined in the NMFS notice of the proposed IHA (71 
FR 58790, October 5, 2006).

Description of the Specified Activity

    The Langseth is expected to depart Mobile, AL in July, 2007 (at the 
earliest) and will transit to the survey area in the northern Gulf of 
Mexico. The survey will encompass an area between 24[deg]N. and 
31[deg]N. and between 83[deg]W. and 96[deg]W., which is within the 
Exclusive Economic Zone (EEZ) of the U.S.A. The study will consist of 
three phases: (1) an initial testing/shakedown phase, (2) measurements 
of the sounds produced by various airgun arrays to be used by the 
Langseth (calibration), and (3) a three-dimensional (3D) seismic 
testing phase. The entire survey, calibration and testing included, 
will take approximately 25 days and include approximately 1420 km (174 
hours) of airgun operation. Measurements will be made during seismic 
operations in three categories of water depth: shallow (<100 m or <328 
ft), intermediate/slope (100-1000 m or 328-3281 ft), and deep (>1000 m 
or >3281 ft). The vessel will transit to Galveston after the study is 
completed. The exact dates of the activities will depend on logistics 
and weather conditions.
    The full airgun array on the Langseth consists of 36 airguns, with 
a total discharge volume of 6600 in\3\. The array is made up of four 
identical linear arrays or strings, with 10 airguns on each string. For 
each operating string, nine airguns will be fired simultaneously, while 
the tenth is kept in reserve as a spare, to be turned on in case of 
failure of another airgun. The calibration phase will use the full 36-
airgun array and subsets thereof. The subsets will consist of either 1 
string (9

[[Page 45745]]

airguns, 1650 in\3\) or 2 strings (18 airguns, 3300 in\3\). In 
addition, sounds from a single 45 in\3\ GI gun and 2 GI guns (210 
in\3\) will be measured. During the seismic testing phase, the 2-string 
array will be used at most times, although the full 36-airgun array may 
also be used. The ocean floor will be mapped with the 12-kHz Simrad 
EM120 MBB sonar. This sonar will be operated from the Langseth 
simultaneous with the airgun array during the seismic testing program, 
but will likely be operated on its own during the acoustic calibration 
study.
    A more detailed description of the authorized action, including 
vessel specifications and acoustic source specifications, was included 
in the notice of the proposed IHA (71 FR 58790, October 5, 2006). Table 
1 includes a summary of the use of the airgun configurations by phase 
and depth.

[[Page 45746]]



------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                      9-Airgun Array (1          18-Airgun Array (2        36-Airgun Array (4
                                          1 GI Gun                  2 GI Guns               1 Single Airgun                Strings)                   Strings)                  Strings)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Airgun Specifications            .........................  .........................  .........................  .........................  .........................  ........................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Energy Source                  One 45 in\3\ GI Airgun     Two 105 in\3\ GI Airguns   One 2000 psi Bolt Airgun   Nine 2000 psi Bolt         Eighteen 2000 psi Bolt     Thirty-six 2000 psi Bolt
                                                                                                                   Airguns of 40-360 in\3\    Airguns of 40-360 in\3\    Airguns of 40-360 in\3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Air Discharge Volume (in\3\)   45 in\3\                   210 in\3\                  40 in\3\                   1650 in\3\                 3300 in\3\                 6600 in\3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Towing Depth of Source         2.5 m                      3 m                        6 m                        6 m                        6 m                        6 m or 12 m
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
  Source Output (dB re 1 miPa    225.3 (230.7)              237 (243)                  .........................  246 (253)                  252 (259)                  259 (265)
   m) 0-pk (pk-pk)*
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Proposed Approximate Airgun Use  .........................  .........................  .........................  .........................  .........................  ........................
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  Calibration Phase              .........................  .........................  .........................  .........................  .........................  ........................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    Shallow Site (30-60 m)       10 km                      10 km                      .........................  34 km                      34 km                      34 km
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    Intermediate/Slope Site      .........................  .........................  .........................  34 km                      34 km                      34 km
(475 m)
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Deep Site (1500)                 10 km                      10 km                      .........................  45 km                      45 km                      45 km
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  Testing Phase                  .........................  .........................  .........................  .........................  .........................  ........................
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    Shallow (<100 m)             .........................  .........................  89 km                      24 km                      175 km                     58 km
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    Intermediate/Slope (100-     .........................  .........................  89 km                      24 km                      175 km                     58 km
     1000 m)
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    Deep (<1000 m)               .........................  .........................  89 km                      24 km                      175 km                     58 km
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Table 1. L-DEO airgun configurations and proposed approximate use for each configuration by depth and phase.
* The root mean square values (typically discussed in biological literature) for these sources will generally be about 10-15 dB lower than those reflected here.


[[Page 45747]]

Safety Radii

    L-DEO has estimated the safety radii around their operations using 
a model, but also by adjusting the model results based on empirical 
data gathered in the Gulf of Mexico in 2003. Additional information 
regarding safety radii in general, how the safety radii were 
calculated, and how the empirical measurements were used to correct the 
modeled numbers may be found in NMFS proposed IHA (71 FR 58790, October 
5, 2006) and Section I and Appendix A of L-DEO's application. Using the 
modeled distances and various correction factors, Table 2 shows the 
distances at which three rms sound levels (190 dB, 180 dB, and 160 dB) 
are expected to be received from the various airgun configurations in 
shallow, intermediate, and deep water depths.

----------------------------------------------------------------------------------------------------------------
                                                                              Predicted RMS Radii (m)
       Source and Volume         Tow Depth (m)     Water Depth    ----------------------------------------------
                                                                       190 DB          180 dB          160 dB
----------------------------------------------------------------------------------------------------------------
                                ..............  Deep               9               25              236
Single Gi gun                   3               Intermediate/      13.5            38              354
                                                 Slope
45 in\3\                        ..............  Shallow            113             185             645
----------------------------------------------------------------------------------------------------------------
                                ..............  Deep               20              69              670
2 Gi guns                       3               Intermediate/      30              104             1005
                                                 Slope
210 in\3\                       ..............  Shallow            294             511             1970
----------------------------------------------------------------------------------------------------------------
                                ..............  Deep               12              36              360
Single Bolt                     6               Intermediate/      18              54              540
                                                 Slope
40 in\3\                        ..............  Shallow            150             267             983
----------------------------------------------------------------------------------------------------------------
1 string                        ..............  Deep               200             650             6200
9 airguns                       6               Intermediate/      300             975             7880
                                                 Slope
1650 in\3\                      ..............  Shallow            1450            2360            8590
----------------------------------------------------------------------------------------------------------------
2 string                        ..............  Deep               250             820             6700
18 airguns                      6               Intermediate/      375             1230            7370
                                                 Slope
3300 in\3\                      ..............  Shallow            1820            3190            8930
----------------------------------------------------------------------------------------------------------------
4 string                        ..............  Deep               410             1320            8000
36 airguns                      6               Intermediate/      615             1980            8800
                                                 Slope
6600 in\3\                      ..............  Shallow            2980            5130            10670
----------------------------------------------------------------------------------------------------------------
4 string                        ..............  Deep               620             1980            12000
36 airguns                      12              Intermediate/      930             2970            13200
                                                 Slope
6600 in\3\                      ..............  Shallow            4500            7700            16000
----------------------------------------------------------------------------------------------------------------
Table 2. Modeled distances to which sound levels 190, 180, and 160 dB re 1 microPa (rms) might be received in
  shallow (<100 m), intermediate/slope (100-1000 m), and deep (>1000 m) water from the various sources planned
  for use during the Gulf of Mexico study, fall 2007.

Comments and Responses

    A notice of receipt of the L-DEO application and proposed IHA was 
published in the Federal Register on October 5, 2006 (71 FR 58790). 
During the comment period, NMFS received comments from the Marine 
Mammal Commission (MMC) and the Center for Regulatory Effectiveness 
(CRE). Following are the comments from the MMC and CRE and NMFS' 
responses:
    Comment 1: The MMC recommends that observations be made during all 
ramp-up procedures to gather data regarding the effectiveness of ramp-
up as a mitigation measure.
    Response: The IHA requires that MMOs on the Langseth make 
observations for the 30 minutes prior to ramp-up, during all ramp-ups, 
and during all daytime seismic operations and record the following 
information when a marine mammal is sighted:
    (i) Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc., and including responses to ramp-up), and 
behavioral pace;
    (ii) Time, location, heading, speed, activity of the vessel 
(including number of airguns operating and whether in state of ramp-up 
or power-down), sea state, visibility, and sun glare.
    These requirements should provide information regarding the 
effectiveness of ramp-up as a mitigation measure, provided animals are 
detected during ramp-up.
    Comment 2: The MMC recommends that the monitoring period prior to 
the initiation of seismic activities be extended to one hour.
    Response: As the MMC points out, several species of deep-diving 
cetaceans are capable of remaining underwater for more than 30 minutes, 
however, for the following reasons NMFS believes that 30 minutes is an 
adequate length for the monitoring period prior to the start-up of 
airguns: (1) because the Langseth is required to ramp-up, the time of 
monitoring prior to start-up of any but the smallest array is 
effectively longer than 30 minutes (Ramp up will begin with the 
smallest gun in the array and airguns will be added in a sequence such 
that the source level of the array will increase in steps not exceeding 
approximately 6 dB per 5-min period over a total duration of 20-30 
min), (2) in many cases MMOs are making observations during times when 
sonar is not being operated and will actually be observing prior to the 
30-minute observation period anyway, (3), the majority of the species 
that may be exposed do not stay underwater more than 30 minutes, and 
(4) all else being equal and if a deep diving individual happened to be 
in the area in the short time immediately prior to the pre-start-up 
monitoring, if an animal's maximum underwater time is 45 minutes, there 
is only a 1 in 3 chance that his last random surfacing would be prior 
to the beginning of the required 30-minute monitoring period.
    Comment 3: The MMC recommends that the Service provide additional

[[Page 45748]]

justification for its proposed determination that marine mammal 
detection ability by trained observers is close to 100 percent during 
daytime (in good weather) and remains high at night.
    Response: The Langseth is utilizing a team of trained MMOs to both 
visually monitor from the high observation tower of the Langseth and to 
conduct passive acoustic monitoring.
    When stationed on the observation platform of the Langseth, the eye 
level will be approximately 17.8 m (58.4 ft) above sea level, so the 
visible distance (in good weather) to the horizon is 8.9 nm (16.5 km) 
(the largest safety radii is 7.7 km (4.2 nm)). Big eyes are most 
effective at scanning the horizon (for blows), while 7 X 50 reticle 
binoculars are more effective closer in (MMOs also use a naked eye 
scan). Additionally, MMOs will have a good view in all directions 
around the entire vessel.
    In some cases, particularly in shallow water and while deploying 
streamers, chase boats will be deployed. The primary mission of the 
chase boat is to warn boats that the seismic vessel is approaching and 
thus the boat will be in front of the seismic vessel (generally about 2 
nm). The plan is to have one MMO on the chase boat, who will advise the 
Langseth of the presence of marine mammals in the operating area when 
forward of the vessel and check for injured animals when aft of the 
vessel.
    Theoretical detection distance of this PAM system is 10s of 
kilometers. One LGL biologist reported - ``Past experience in the GOM 
would indicate good detection rates out to several kilometers. It is 
not unreasonable to state that the PAM will detect most marine mammal 
calls within the 3 km safety radius, particularly clicks from sperm 
whales.'' The PAM is operated both during the day and at night.
    Though it depends on the lights on the ship, the sea state, and 
thermal factors, MMOs estimated that visual detection is effective out 
to between 150 and 250 m using NVDs and about 30 m with the naked eye. 
However, the PAM operates equally as effectively at night as during the 
day, especially for sperm whales and dolphins (dolphins are the only 
species likely to be detected in the ``shallow'' depths, where the 
safety zones are the largest).
    Comment 4: The MMC recommends that NMFS take steps to ensure that 
the planned monitoring program will be sufficient to detect, with 
reasonable certainty, all marine mammals within or entering identified 
safety zones.
    Response: Based on the information provided in the previous comment 
(above) and the following information, NMFS believes that the planned 
monitoring program will be sufficient to detect (using visual detection 
and PAM), with reasonable certainty, all marine mammals within or 
entering identified safety zones.
    As mentioned above, the platform of the Langseth is high enough 
that, in good weather, MMOs can see out to 8.9 nm (16.5 km). The PAM 
has reliable detection rates out to 3 km and more limited ability out 
to 10s of km. The largest 180-dB safety radii (3.2, 5.1, and 7.7 km), 
which is the radii within which the Langseth is required to shut down 
if a marine mammal enters, are found when the 9-gun, 18-gun, and 36-gun 
arrays are operating in shallow water. The species most likely to be 
encountered in the shallow water of the GOM, by far, are bottlenose and 
Atlantic spotted dolphins, which have relatively larger group sizes (6-
10 animals for Atlantic spotted and 1-90 animals for bottlenose), are 
not cryptic at the surface, and have relatively short dive times (< 2 
minutes for Atlantic spotted and 5-12 minutes for bottlenose), all 
which generally make them easier to visually detect. Additionally, the 
vocalizations of these species are easily detected by the PAM. 
Additionally, as mentioned above, MMOs on chase boats will sometimes be 
used in addition to visual monitoring from the seismic vessels and PAM. 
During the Maurice Ewing cruise in the GOM in 2003, MMOs detected 
marine mammals at a distance of approximately 10 km from the vessel and 
identified them to species at approximately 5 km from the vessel, 
though the bridge of that vessel was only 11 m above the water (vs. the 
Langseth, which is 17 m above). All of the 180-dB safety radii for 
other depths are less than 3 km (all less than 2 km, except the 36-gun 
array at intermediate depth, which is 2.97 km).
    The likelihood of visual detection at night is significantly lower 
than during the day, though the PAM remains just as effective at night 
as during the day. However, the Langseth will not be starting up the 
airguns unless the safety range is visible for the entire 30 minutes 
prior (i.e., not an night), and therefore in all cases at night, the 
airguns will already be operating, which NMFS believes will cause many 
cetaceans to avoid the vessel, which therefore will reduce the number 
likely to come within the safety radii. Additionally, because of normal 
operating procedures, which entail beginning seismic operations as soon 
after dawn as possible, at the most 33% of the actual airgun operation 
(and much less, most likely) will occur at nighttime. With the 
exception of operation of airguns in shallow water (which between the 
9-, 18-, and 36-gun array totals about 18 hours), all of the other 
safety radii are smaller than 3 km and fall easily within the reliable 
detection capabilities of the PAM.
    Comment 5: The CRE believes that NMFS should grant the Lamont-
Doherty Earth Observatory an IHA for L-DEO's proposed seismic 
experiments in the GOM. However, the CRE recommended that NMFS revise 
the IHA to state:
    (1) There is no evidence that Gulf seismic operations complying 
with the traditional 500 meter safety radii have injured marine mammals 
or any other marine life.
    (2) The much larger safety radii in the proposed IHA are based on 
flawed models and unreliable data.
    (3) Visual observation and PAM cannot accurately and reliably 
monitor for marine mammals in safety radii significantly larger than 
the traditional 500 meters.
    Response:
    (1) Neither the proposed IHA nor this Federal Register notice state 
that Gulf seismic operations, utilizing any size safety zone, have 
injured marine mammals. The proposed IHA states that there is ``no 
specific evidence that exposure to pulses of airgun sound can cause PTS 
in any marine mammal'' and that ``Airgun pulses are less energetic and 
have slower rise times [than explosives], and there is no proof that 
they can cause serious injury, death, or stranding even in the case of 
large airgun arrays''.
    (2) As CRE points out in their letter, L-DEO acknowledges in their 
application the shortcomings of the 2003 data collection using airguns 
in the GOM, however, this is the best available data for seismic sound 
propagation in the GOM and L-DEO further explains (see proposed IHA) 
how they use conservative correction factors in the development of 
appropriate safety radii (based on the 180-dB criteria prescribed by 
NMFS). The purpose of the current L-DEO seismic calibration is to 
improve these data for use in future operations and MMPA 
authorizations.
    (3) NMFS believes that between visual monitoring and PAM the MMOs 
can accurately and reliably detect marine mammals within safety radii 
significantly larger than 500 m (see NMFS' responses to comments 3 and 
4).

Description of Marine Mammals in the Activity Area

    In the Gulf of Mexico, 28 cetacean species and one species of 
manatee are known to occur (Jefferson and Schiro, 1997; Wursig et al., 
2000). In the U.S.,

[[Page 45749]]

manatees are managed by the U.S. Fish & Wildlife Service (USFWS), are 
unlikely to be encountered in or near the open waters of the Gulf of 
Mexico where seismic operations will occur, and are, therefore, not 
addressed further in this document. Most of these species of cetaceans 
occur in oceanic waters (>200 m or 656 ft deep) of the Gulf, whereas 
the continental shelf waters (<200 m) are primarily inhabited by 
bottlenose dolphins and Atlantic spotted dolphins (Mullin and Fulling 
2004).
    Seven species that may occur in the Gulf of Mexico are listed as 
endangered under provisions of the U.S. Endangered Species Act (ESA), 
including the sperm, North Atlantic right, humpback, sei, fin, and blue 
whale, as well as the West Indian manatee. However, of those species, 
only sperm whales are likely to be encountered. In addition to the 28 
species known to occur in the Gulf of Mexico, another three species of 
cetaceans could potentially occur there: the long-finned pilot whale, 
the long-beaked common dolphin, and the short-beaked common dolphin 
(Table 3). Though any pinnipeds sighted in the study area would be 
extralimital, hooded seals have been reported in Florida and L-DEO has 
requested authorization for the take of 2 animals.
    During the 2003 acoustical calibration study in the Gulf of Mexico 
from 28 May to 2 June, a total of seven visual sightings of marine 
mammals were documented from the Maurice Ewing; these included a total 
of approximately 38-40 individuals (LGL Ltd. 2003). In addition, three 
sea turtles were sighted. These totals include times when airguns were 
not operating as well as times

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                      BEST                                  MAXIMUM
                                                                                        Abundance in GOM and/or   ------------------------------------------------------------------------------
             Species                         Habitat              Occurrence in GOM          North Atlantic                                  Approx. % of      Ext. Exposures     Approx.C% of
                                                                                                                    Estimated Exposures       Population         Auth IHA**        Population
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
----------------------------------
Sperm whale                        Usually pelagic and deep     Common                1349 / 13190 (add)           22                    0.2                  22                0.2
                                    seas
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy sperm whale                  Deeper waters off the shelf  Common                742 / 695 (add)              56                    3.9                  59                4.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dwarf sperm whale                  Deeper waters off the shelf  Common                742 / 695 (add)              56                    3.9                  59                4.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale              Pelagic                      Rare                  159 / 3196 (add)             10                    0.3                  21                0.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sowerby's beaked whale             Pelagic                      Extralimital          106 / 541 (add)              5                     0.8                  8                 1.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gervais' beaked whale              Pelagic                      Uncommon              106 / 541 (add)              5                     0.8                  8                 1.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blainville's beaked whale          Pelagic                      Rare                  106 / 541 (add)              5                     0.8                  8                 1.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Rough-toothed dolphin              Mostly pelagic               Common                2223 / 274 (add)             58                    2.3                  92                3.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin                 Cont. shelf, coastal and     Common                25,320 / 2239 / 29774 (add)  773                   1.3                  1713              5.0
                                    offshore
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pantropical spotted dolphin        Mainly pelagic               Common                91,321 / 13117 (add)         1282                  1.2                  1587              1.5
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin           Mainly coastal waters        Common                30,947 / 52279 (add)         876                   1.1                  1755              0.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Spinner dolphin                    Pelagic in Gulf of Mexico    Common                11,971                       168                   1.4                  921               7.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Clymene dolphin                    Pelagic                      Common                17,355 / 6086 (add)          244                   1.0                  311               1.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Striped dolphin                    Off the continental shelf    Common                6505 / 61546 (add)           91                    0.1                  134               0.2
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Short-beaked common dolphin        Continental shelf and        Possible              30,768                       0                     0.0                  0 (5)**           <0.1
                                    pelagic waters
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Long-beaked common dolphin         Coastal                      Possible              N.A.                         0                     0.0                  0 (5)**           0.0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fraser's dolphin                   Water >1000m                 Common                726                          10                    1.4                  60                8.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Risso's dolphin                    Waters 400-1000m             Common                2169 / 29110 (add)           54                    0.2                  81                0.3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Melon-headed whale                 Oceanic                      Common                3451                         49                    1.4                  142               4.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 45750]]

 
Pygmy killer whale                 Oceanic                      Uncommon              408                          10                    2.6                  21                5.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
False killer whale                 Pelagic                      Uncommon              1038                         14                    1.4                  28                2.7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale                       Widely distributed           Uncommon              133 / 6600 (add)             3                     <0.1                 5                 0.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Short-finned pilot whale           Mostly pelagic               Common                2388 / 780000 / 14524        34                    <0.1                 98                <0.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Long-finned pilot whale            Mostly pelagic               Possible              N.A.                         0                     ...................  0 (5)**           ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mysticetes
----------------------------------
North Atlantic right whale*        Coastal and shelf waters     Extralimital          291                          0                     ...................  0                 ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale*                    Mainly near-shore waters /   Rare                  11,570 / 10400               0                     ...................  0                 ................
                                    banks
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Minke whale                        Coastal waters               Rare                  149,000                      0                     ...................  0                 ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale                      Pelagic and coastal          Uncommon              40 / 90000                   1                     2.5                  2                 5.0
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Sei whale*                         Primarily offshore, pelagic  Rare                  12-13,000                    0                     ...................  0                 ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale*                         Cont. slope, mostly pelagic  Rare                  2814 / 47300                 0                     ...................  0                 ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale*                        Coastal, shelf, and oceanic  Extralimital          308                          0                     ...................  0                 ................
                                    waters
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Pinnipeds
----------------------------------
Hood seal                          Coastal                      Vagrant               400,000\z\                   0                     ...................  0 (2)**           <0.1
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                              3770                  ...................  7096              ................
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Table 3. Abundance, preferred hatitat, and commonness of the marine mammals species found in the survey area. The far right columns indicate the estimated number of each species that will be
  exposed to 160 dB based on best and maximum density estimates. NMFS believes that, when mitigation measures are taken into consideration, the activity is likely to result in take of numbers
  of animals less than those indicated by the best column, however, NMFS has authorized the number in this column.
* Federally listed endangered
** Parenthetical number indicates take authorization, though exposure estimate is 0

    when airguns were firing. Visual monitoring effort consisted of 
60.9 hours of observations (all in daylight) along 891.5 km of vessel 
trackline on seven days, and passive acoustic monitoring (PAM) occurred 
for approximately 32 hours. Most of the monitoring effort (visual as 
well as acoustic) occurred when airguns were not operating, since 
airgun operations were limited during the 2003 study. No marine mammals 
were detected during acoustic monitoring. Marine mammal and sea turtle 
sightings and locations during the 2003 calibration study are 
summarized in Appendix C of L-DEOs application.
    Additional information regarding the status and distribution of the 
marine mammals in the area and how the densities were calculated was 
included in the notice of the proposed IHA (71 FR 58790) and may be 
found in L-DEO's application.

Potential Effects of the Activity on Marine Mammals

    The effects of sounds from airguns might include one or more of the 
following: tolerance, masking of natural sounds, behavioral 
disturbance, temporary or permanent hearing impairment (Richardson et 
al., 1995), or other non-auditory physiological effects such as stress, 
neurological effects, bubble formation, resonance effects, and other 
types of organ or tissue damage. To avoid injury, NMFS has determined 
that cetaceans and pinnipeds should not be exposed to pulsed underwater 
noise at received levels exceeding, respectively, 180 and 190 dB re 1 
microPa (rms). The predicted 180- and 190-dB distances for the GI guns 
operated by SIO are summarized in Table 2. Given the required 
mitigation and monitoring measures, it is unlikely that there would be 
any cases of temporary or, especially, permanent hearing impairment or 
other serious non-auditory physiological effects.
    The notice of the proposed IHA (71 FR 58790, October 5, 2006) 
included a discussion of the effects of sounds from airguns on 
mysticetes, odontocetes, and pinnipeds, including tolerance, masking, 
behavioral disturbance, hearing impairment and other non-auditory 
physical effects. Additional details on the behavioral reactions (or 
the lack thereof) by all types of marine mammals to seismic vessels can 
be found in Appendix A (e) of L-DEO's application.
    The notice of the proposed IHA also included a discussion of the 
potential effects of the bathymetric sonar. Because of the shape of the 
beam of this source

[[Page 45751]]

and its power, NMFS believes it unlikely that marine mammals will be 
exposed to bathymetric sonar at levels at or above those likely to 
cause harassment. Further, NMFS believes that the brief exposure of 
cetaceans or pinnipeds to small numbers of signals from the multi-beam 
bathymetric sonar system are not likely to result in the harassment of 
marine mammals.

Monitoring and Mitigation Measures

Monitoring

    L-DEO will conduct mammal monitoring of its seismic program, in 
order to implement the planned mitigation measures and to satisfy the 
requirements of the IHA. More information regarding the Monitoring 
program (including both visual observation and passive acoustic 
detection) was included in NMFS' proposed IHA (71 FR 58790, October 5, 
2006).
Vessel Based Monitoring
    Vessel-based marine mammal observers (MMOs) will watch for marine 
mammals near the seismic source vessel during all daytime airgun 
operations and during any start ups of the airguns at night. When 
feasible, observations will also be made during daytime periods without 
seismic operations (e.g., during transits).
    During seismic operations in the Gulf of Mexico, five observers 
will be based aboard the vessel. MMOs will be appointed by L-DEO with 
NMFS concurrence. At least one MMO, and when practical two MMOs, will 
watch for marine mammals near the seismic vessel during ongoing daytime 
operations and nighttime start ups of the airguns. MMO(s) will be on 
duty in shifts of duration no longer than 4 h. The crew will also be 
instructed to assist in detecting marine mammals and implementing 
mitigation requirements (if practicable). Before the start of the 
seismic survey the crew will be given additional instruction in how to 
do so.
    The Langseth is a suitable platform for marine mammal observations. 
When stationed on the observation platform, the eye level will be 
approximately 17.8 m (58.4 ft) above sea level, and the observer will 
have a good view around the entire vessel. However, neither the actual 
bow of the vessel nor the stern will be visible from the observation 
platform, although it will be possible to see the airguns. To monitor 
the areas immediately at the bow and stern of the vessel, two video 
cameras will be installed at the bow (one on the starboard and one on 
the port side), and a wide-angle camera will be installed at the stern. 
Real-time footage from these cameras will be played on the observation 
platform, so that the MMO(s) are able to monitor those areas. In 
addition a high-power video camera will be mounted on the observation 
platform to assist with species identification.
    During daytime, the MMO(s) will scan the area around the vessel 
systematically with reticle binoculars (e.g., 7 50 Fujinon), Big-eye 
binoculars (25 150), and with the naked eye. At night, Night Vision 
Devices (NVDs) will be available (ITT F500 Series Generation 3 
binocular-image intensifier or equivalent), when required. Laser 
rangefinding binoculars (Leica LRF 1200 laser rangefinder or 
equivalent) will be available to assist with distance estimation. Those 
are useful in training observers to estimate distances visually, but 
are generally not useful in measuring distances to animals directly.
    MMOs will not be on duty during ongoing seismic operations at 
night. At night, bridge personnel will watch for marine mammals. If the 
airguns are started up at night, two MMOs will watch for marine mammals 
near the source vessel for 30 min prior to start up of the airguns 
using NVDs, if the proper conditions for nighttime start up exist (see 
Mitigation below).
     The vessel-based monitoring will provide data to estimate the 
numbers of marine mammals exposed to various received sound levels, to 
document any apparent disturbance reactions or lack thereof, and thus 
to estimate the numbers of mammals potentially ``taken'' by harassment. 
It will also provide the information needed in order to power down or 
shut down the airguns at times when mammals are present in or near the 
safety radii. When a sighting is made, the following information about 
the sighting will be recorded:
    1. Species, group size, age/size/sex categories (if determinable), 
behavior when first sighted and after initial sighting, heading (if 
consistent), bearing and distance from seismic vessel, sighting cue, 
apparent reaction to the airguns or vessel (e.g., none, avoidance, 
approach, paralleling, etc.), and behavioral pace.
    2. Time, location, heading, speed, activity of the vessel, sea 
state, visibility, and sun glare.
    The data listed under (2) will also be recorded at the start and 
end of each observation watch, and during a watch whenever there is a 
change in one or more of the variables.
    All observations and power-downs or shut downs (see Mitigation 
below) will be recorded in a standardized format. Data will be entered 
into a custom database using a notebook computer. The accuracy of the 
data entry will be verified by computerized validity data checks as the 
data are entered and by subsequent manual checking of the database. 
These procedures will allow initial summaries of data to be prepared 
during and shortly after the field program, and will facilitate 
transfer of the data to statistical, graphical, or other programs for 
further processing and archiving.
Passive Acoustic Monitoring
    Passive acoustic monitoring will take place to complement the 
visual monitoring program. Visual monitoring typically is less 
effective during periods of bad weather or at night, and even with good 
visibility, is unable to detect marine mammals when they are below the 
surface or beyond visual range. Acoustical monitoring can be used in 
addition to visual observations to improve detection, identification, 
localization, and tracking of cetaceans. The acoustic monitoring will 
serve to alert visual observers when vocalizing cetaceans are detected. 
It will be monitored in real time so that the visual observers can be 
advised when cetaceans are detected.
    SEAMAP (Houston, TX) will be used as the primary acoustic 
monitoring system. This system was also used during previous L-DEO 
seismic cruises (e.g., Smultea et al., 2004, 2005; Holst et al., 
2004a,b). The PAM system consists of hardware (i.e., the hydrophone) 
and software. The ``wet end'' of the SEAMAP system consists of a low-
noise, towed hydrophone array that is connected to the vessel by a 
``hairy'' faired cable. The array will be deployed from a winch located 
on the back deck. A deck cable will connect from the winch to the main 
computer lab where the acoustic station and signal conditioning and 
processing system will be located. The lead-in from the hydrophone 
array is approximately 400 m (1312 ft) long, and the active part of the 
hydrophone array is approximately 56 m (184 ft) long. The hydrophone 
array is typically towed at depths of less than 20 m or 66 ft.
    The acoustical array will be monitored 24 hours per day while at 
the seismic survey area during airgun operations and during most 
periods when airguns are not operating. One MMO will monitor the 
acoustic detection system at any one time, by listening to the signals 
from two channels via headphones and/or speakers and watching the real-
time spectrographic display for frequency ranges produced by cetaceans. 
MMOs

[[Page 45752]]

monitoring the acoustical data will be on shift from 1-6 h. All MMOs 
are expected to rotate through the PAM position, although the most 
experienced with acoustics will be on PAM duty more frequently.
    When a vocalization is detected, the acoustic MMO will contact the 
visual MMO immediately (so a power-down or shut down can be initiated, 
if required), and the information regarding the call will be entered 
into a database. The data to be entered include an acoustic encounter 
identification number, whether it was linked with a visual sighting, 
GMT date, GMT time when first and last heard and whenever any 
additional information was recorded, GPS position and water depth when 
first detected, species or species group (e.g., unidentified dolphin, 
sperm whale), types and nature of sounds heard (e.g., clicks, 
continuous, sporadic, whistles, creaks, burst pulses, strength of 
signal, etc.), and any other notable information. The acoustic 
detection can also be recorded onto the hard-drive for further 
analysis.

Mitigation

    L-DEO's study in the northern Gulf of Mexico will deploy an energy 
source of up to 36 airguns (6600 in\3\). The airguns comprising the 
array will be spread out horizontally, so that the energy will be 
directed mostly downward. This directionality will result in reduced 
sound levels at any given horizontal distance than would be expected at 
that distance if the source were omnidirectional with the stated 
nominal source level.
    Localized and temporally-variable areas of concentrated feeding or 
of special significance for marine mammals may occur within or near the 
planned area of operations during the season of operations. However, L-
DEO will avoid conducting the activities near important concentrations 
of marine mammals insofar as these can be identified in advance from 
other sources of information, or during the cruise.
Safety Radii
    As noted earlier (Table 2), received sound levels were modeled by 
L-DEO for various configurations of the 36-airgun array in relation to 
distance and direction from the airguns, and for a single and 2 GI 
guns. Correction factors based on empirical measurements were applied 
to estimate safety radii in shallow and intermediate-depth water. The 
distances from the airguns where sound levels of 190, 180, and 160 dB 
re 1 microPa (rms) are estimated to be received are shown Table 2. 
Also, the safety radii for a single (40 in\3\) airgun are given, as 
that source will be in operation when the 36-airgun array is powered 
down. Airguns will be powered down (or shut down if necessary) 
immediately when marine mammals are detected within or about to enter 
the appropriate radius: 180 dB (rms) for cetaceans, and 190 dB (rms) 
for pinnipeds, in the very unlikely event that pinnipeds are 
encountered.
Mitigation During Operations
    Mitigation measures that will be required will include (1) speed or 
course alteration, provided that doing so will not compromise 
operational safety requirements, (2) power-down procedures, (3) shut-
down procedures, (4) special shut-down procedures for baleen whales at 
any distance, (5) ramp-up procedures, (6) avoidance of submarine 
canyons and areas with known concentrations of marine mammals, if 
possible, and (7) shut down and notification of NMFS if an injured or 
dead marine mammal is found and is judged likely to have resulted from 
the operation of the airguns.
    Speed or Course Alteration--If a marine mammal or is detected 
outside the 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 may be changed. This would be done if practicable while 
minimizing the effect to the planned science objectives. The activities 
and movements of the marine mammal or sea turtle (relative to the 
seismic vessel) will be closely monitored to determine whether the 
animal is approaching the applicable safety radius. If the animal 
appears likely to enter the safety radius, further mitigative actions 
will be taken, i.e., either further course alterations or a power-down 
or shut down of the airguns.
    Power-down Procedures--A power-down involves decreasing the number 
of airguns in use such that the radius of the 18-dB (or 190-dB) zone is 
decreased to the extent that marine mammals are no longer in or about 
to enter the safety zone. A power-down may also occur when the vessel 
is moving from one seismic line to another (ie., during a turn). During 
a power-down, one airgun will be operated. The continued operation of 
one airgun is intended to alert marine mammals to the presence of the 
seismic vessel in the area. In contrast, a shut down occurs when all 
airgun activity is suspended.
    If a marine mammal is detected outside the safety zone but is 
likely to enter the safety radius, and if the vessel's speed and/or 
course cannot be changed to avoid having the animal enter the safety 
radius, the airguns will be powered down before the animal is within 
the safety radius. Likewise, if a mammal or turtle is already within 
the safety zone when first detected, the airguns will be powered down 
immediately. During a power-down of the airgun array, at least one 
airgun (e.g., 40 in3) will be operated. If a marine mammal is detected 
within or near the smaller safety radius around that single airgun 
(Table 2), all airguns will be shut down (see next subsection).
    Following a power-down, airgun activity will not resume until the 
marine mammal has cleared the safety zone. The animal will be 
considered to have cleared the safety zone if it: (1) is visually 
observed to have left the safety zone; or, (2) has not been seen within 
the zone for 15 min in the case of small odontocetes and pinnipeds; or, 
(3) has not been seen within the zone for 30 min in the case of 
mysticetes and large odontocetes, including sperm, pygmy sperm, dwarf 
sperm, and beaked whales.
    During airgun operations following a power-down whose duration has 
exceeded specified limits, the airgun array will be ramped up 
gradually. Ramp-up procedures are described below.
    Shut-down Procedures--During a power-down, the operating airgun 
will be shut down if a marine mammal approaches within the modeled 
safety radius for the then-operating source, typically a single 40 in3 
gun or a GI gun (Table 2). If a marine mammal is detected within or 
about to enter the appropriate safety radius around the small source in 
use during a power-down, airgun operations will be entirely shut down.
    Airgun activity will not resume until the animal has cleared the 
safety zone, or until the MMO is confident that the marine mammal has 
left the vicinity of the vessel. Criteria for judging that the animal 
has cleared the safety zone will be as described in the preceding 
subsection.
    Special Shut-down Provision for Mysticetes--The airguns will be 
shut down (not just powered down) if a mysticete is sighted anywhere 
near the vessel, even if the whale is located outside the safety 
radius. This measure is planned because of the assumed greater effects 
of seismic surveys on mysticetes in general (as compared with other 
marine mammals).
    Ramp-up Procedures - A ramp-up procedure will be followed when the 
airgun array begins operating after a specified-duration without airgun 
operations. For the present cruise, this period would be approximately 
10 min. This duration is based on provisions

[[Page 45753]]

during previous L-DEO surveys and on the approximately 180-dB radius 
for the 4-string array in deep water in relation to the planned speed 
of the Langseth while shooting. Ramp up will begin with the smallest 
gun in the array. Airguns will be added in a sequence such that the 
source level of the array will increase in steps not exceeding 
approximately 6 dB per 5-min period over a total duration of 20-30 min. 
During ramp up, the safety zone for the full airgun array to be used 
will be maintained.
    If the complete safety radius has not been visible for at least 30 
min prior to the start of operations in either daylight or nighttime, 
ramp up will not commence unless at least one airgun has been operating 
during the interruption of seismic survey operations. That airgun will 
have a source level of more than 180 dB re 1 microPa . m (rms). It is 
likely that the airgun array will not be ramped up from a complete shut 
down at night or in thick fog (the array will definitely not be ramped 
up from a complete shut down at night in shallow water), because the 
outer part of the safety zone for the array will not be visible during 
those conditions. If one airgun has operated during a power-down 
period, ramp up to full power will be permissible at night or in poor 
visibility, on the assumption that marine mammals will be alerted to 
the approaching seismic vessel by the sounds from the single airgun and 
could move away if they choose. Ramp up of the airguns will not be 
initiated if a marine mammal is sighted within or near the applicable 
safety radii during the day or close to the vessel at night.
    Avoidance of Areas with Concentrations of Marine Mammals - Beaked 
whales may be highly sensitive to sounds produced by airguns, based 
mainly on what is known about their responses to other sound sources. 
Beaked whales tend to concentrate in continental slope areas, and 
especially in areas where there are submarine canyons on the slope. 
Therefore, L DEO will, if possible, avoid airgun operations over or 
near submarine canyons within the present study area. Also, if 
concentrations of beaked whales are observed at the slope site just 
prior to or during the airgun operations there, those operations will 
be moved to another location along the slope based on recommendations 
by the lead MMO aboard the Langseth. Furthermore, any areas where 
concentrations of sperm whales are known to be present will be avoided 
if possible.
    Shutdown if Injured or Dead Whale is Found - In the unanticipated 
event that any cases of marine mammal injury or mortality are found and 
are judged likely to have resulted from these activities, L-DEO will 
cease operating seismic airguns and report the incident to the Office 
of Protected Resources, NMFS immediately.

Reporting

    L-DEO will provide brief field reports on the progress of the 
project on a weekly basis.
    A report will be submitted to NMFS within 90 days after the end of 
the cruise. The report will describe the operations that were conducted 
and the marine mammals and turtles that were detected near the 
operations. The report will be submitted to NMFS, providing full 
documentation of methods, results, and interpretation pertaining to all 
monitoring. The 90-day report will summarize the dates and locations of 
seismic operations, and all marine mammal and turtle sightings (dates, 
times, locations, activities, associated seismic survey activities). 
The report will also include estimates of the amount and nature of 
potential ``take'' of marine mammals by harassment or in other ways.

Estimated Take by Incidental Harassment

    The notice of the proposed IHA (71 FR 58790, October 5, 2006) 
included an in-depth discussion of the methods used to calculate the 
densities of marine mammals in the area of the seismic airgun operation 
and the take estimates. Additional information was included in section 
VII of L-DEO's application. A summary of the total take authorized by 
NMFS is included here in Table 3. Generally, estimates of the numbers 
of marine mammals that might be affected during the seismic program in 
the northern Gulf of Mexico are based on consideration of the number of 
marine mammals that might be exposed to 160 dB along the 1420 km (767 
nm) trackline of seismic surveys during the Gulf of Mexico program. The 
numbers of animals estimated below do not take into consideration the 
implementation of mitigation measures and, therefore, probably 
overestimate the take to some degree.
    Because of the mitigation measures that will be required and the 
likelihood that some cetaceans will avoid the area around the operating 
airguns of their own accord, NMFS does not expect any marine mammals to 
approach the sound source close enough to be injured (Level A 
harassment). All anticipated takes would be ``takes by Level B 
harassment'', as described previously, involving temporary behavioral 
modifications or low level physiological effects.
    The ``best estimate'' of the number of individual marine mammals 
that might be exposed, absent any mitigation measures, to seismic 
sounds with received levels 160 dB re 1 microPa (rms) is 3770 (Table 
3). That total includes 22 endangered sperm whales, 25 beaked whales, 
and one Bryde's whale (Table 3). Pantropical spotted dolphins, Atlantic 
spotted dolphins, and bottlenose dolphins are expected to be the most 
common species in the study area; the best estimates for those species, 
absent any mitigation, are 1282, 876, and 773, respectively (Table 3). 
Estimates for other species are lower.
    The ``Maximum Estimate'' column in Table 3 shows estimates totaling 
7082 individual marine mammals based on maximum densities, and taking 
into account an adjustment for small numbers of other species that 
might be encountered in the survey area, even though there were not 
recorded during previous surveys. These are the numbers for which 
``take authorization'' is requested. NMFS does not expect the total 
number of marine mammal takes to be this high, however, it is 
appropriate to err on the cautious side to ensure that L-DEO is covered 
in the event that an unexpectedly large number of any particular 
species were exposed to >160 dB during the survey and, further, to 
ensure that this exposure would result in a negligible impact to the 
species or stock.
    Based on numbers of animals encountered during L-DEO's 2003 cruise 
in the Gulf of Mexico, the likelihood of the successful implementation 
of the required mitigation measure, and the likelihood that some 
animals will avoid the area around the operating airguns, NMFS believes 
that L-DEOs airgun calibration and seismic testing program may result 
in the Level B harassment of some lower number of individual marine 
mammals than is indicated by the ``best estimates'' in Table 3. These 
best estimates compose no more than 3.9 percent of any given species 
population in the northern Gulf of Mexico, and NMFS has determined that 
these numbers are small relative to the population sizes in the 
specified geographic area (Table 3). L-DEO has asked for authorization 
for take of their ``maximum estimate'' of numbers for each species, 
which includes the take of two hooded seals. Though NMFS believes that 
take of the maximum numbers is unlikely, we still find these numbers 
small (up to 8.3 percent of the Fraser's dolphin population and 7.7 
percent of the spinner dolphin

[[Page 45754]]

population, but less than 5 percent the others) relative to the 
population sizes.

Potential Effects on Habitat

    A detailed discussion of the potential effects of this action on 
the marine mammal habitat, including physiological and behavioral 
effects on marine fish and invertebrates, was included in the notice of 
the proposed IHA (71 FR 58790, October 5, 2007).
    The main impact issue associated with the activity will be 
temporarily elevated noise levels and the associated direct effects on 
marine mammals. Based on the discussion in the proposed IHA, the 
authorized operations are not expected to have any habitat-related 
effects that could cause significant or long-term consequences for 
individual marine mammals or their populations or stocks.
Negligible Impact Determination
    NMFS has determined, provided that the aforementioned mitigation 
and monitoring measures are implemented, that the impact of conducting 
an acoustic calibration and seismic testing program in the Gulf of 
Mexico may result, at worst, in a temporary modification in behavior 
and/or low-level physiological effects (Level B Harassment) of small 
numbers of certain species of marine mammals. While behavioral and 
avoidance reactions may be made by these species in response to the 
resultant noise from the airguns, these behavioral changes are expected 
to have a negligible impact on the affected species and stocks of 
marine mammals.
    While the number of potential incidental harassment takes will 
depend on the distribution and abundance of marine mammals in the area 
of seismic operations, the number of potential harassment takings is 
estimated to be relatively small in light of the population size (see 
Table 3). NMFS anticipates the actual take of individuals to be lower 
than the numbers depicted in the table, because those numbers do not 
reflect either the implementation of the mitigation measures or the 
fact that some animals will avoid the sound at levels lower than those 
expected to result in harassment. Additionally, mitigation measures 
require that the Langseth avoid any areas where marine mammals are 
concentrated.
    In addition, no take by death and/or serious injury is anticipated, 
and the potential for temporary or permanent hearing impairment will be 
avoided through the incorporation of the required mitigation measures 
described in this document. This determination is supported by (1) the 
likelihood that, given sufficient notice through slow ship speed and 
ramp-up of the seismic array, marine mammals are expected to move away 
from a noise source that it is annoying prior to its becoming 
potentially injurious; (2) TTS is unlikely to occur, especially in 
odontocetes, until levels above 180 dB re 1 microPa are reached; (3) 
the fact that injurious levels of sound are only likely close to the 
vessel; and (4) the likelihood of detection of marine mammals within 
the safety radii developed to avoid injury is high due to the height of 
the Langseth's bridge and the use of a passive acoustic detection 
system.

Endangered Species Act

    Pursuant to section 7 of the ESA, the National Science Foundation 
(NSF) has consulted with NMFS on this seismic survey. NMFS has also 
consulted internally pursuant to Section 7 of the ESA on the issuance 
of an IHA under section 101(a)(5)(D) of the MMPA for this activity. In 
a Biological Opinion (BO), NMFS concluded that the 2007 L-DEO seismic 
survey in the northern GOM and the issuance of the associated IHA are 
not likely to jeopardize the continued existence of threatened or 
endangered species or destroy or adversely modify any designated 
critical habitat. NMFS has issued an incidental take statement (ITS) 
for 22 sperm whales (as well as a number of individuals of green, 
hawksbill, Kemp's ridley, leatherback, and loggerhead sea turtles) that 
contains reasonable and prudent measures with implementing terms and 
conditions to minimize the effects of this take. The terms and 
conditions of the Biological Opinion that apply to listed marine 
mammals have been incorporated into the IHA.

National Environmental Policy Act (NEPA)

    In 2003, NSF prepared an Environmental Assessment (EA) for a marine 
seismic survey by the R/V Maurice Ewing in the Northern Gulf of Mexico. 
This EA addressed the potential effects of a different combination of 
airgun arrays (20 airguns, total volume 8580 in3) being operated in the 
same part of the ocean and affecting the same populations of marine 
mammals as is proposed for the Langseth in this application. NMFS 
adopted NSF's EA in 2003 and prepared a supplemental EA in 2007 to 
clarify the differences between the two activities and their potential 
effects on the environment. NMFS has issued a Finding of Significant 
based on NSF's 2003 EA and NMFS supplemental EA.

Conclusions

    Based on the preceding information, and provided that the required 
mitigation and monitoring are incorporated, NMFS has concluded that the 
activity will incidentally take, by Level B harassment only, small 
numbers of marine mammals. NMFS has further determined that L-DEO's 
calibration study will have a negligible impact on the affected species 
or stocks of marine mammals and will not have an unmitigable adverse 
impact on the availability of the affected species or stocks for 
subsistence uses.
    Authorization
    NMFS has issued an IHA to L-DEO for an acoustic calibration and 
seismic testing program in the northern Gulf of Mexico in Fall, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated.

    Dated: July 27, 2007.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. E7-16013 Filed 8-14-07; 8:45 am]
BILLING CODE 3510-22-S