Small Takes of Marine Mammals Incidental to Specified Activities; Marine Geophysical Survey off Central America, February-April 2008, 9526-9535 [E8-3256]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 73, Number 35 (Thursday, February 21, 2008)]
[Notices]
[Pages 9526-9535]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-3256]


-----------------------------------------------------------------------

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF33


Small Takes of Marine Mammals Incidental to Specified Activities; 
Marine Geophysical Survey off Central America, February-April 2008

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

ACTION: Notice; issuance of incidental take authorization.

-----------------------------------------------------------------------

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 Lamont-Doherty Earth 
Observatory (L-DEO), a part of Columbia University, for the take of 
marine mammals, by Level B harassment only, incidental to conducting a 
marine seismic survey off Central America during February-April, 2008.

DATES: Effective February 15, 2008, through February 14, 2009.

ADDRESSES: A copy of the IHA and the application are available by 
writing to P. 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 the references used in this document may be 
obtained by writing to the address specified above, telephoning the 
contact listed below (see FOR FURTHER INFORMATION CONTACT), or visiting 
the internet at: https://www.nmfs.noaa.gov/pr/permits/
incidental.htm#applications. Documents cited in this notice may be 
viewed, by appointment, during regular business hours, at the 
aforementioned address.

FOR FURTHER INFORMATION CONTACT: Candace Nachman, Office of Protected 
Resources, NMFS, (301) 713-2289 x156.

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 (where relevant), and if 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].

[[Page 9527]]

    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 approve or deny the authorization.

Summary of Request

    On August 24, 2007, NMFS received an application from L-DEO for the 
taking, by Level B harassment only, of small numbers of 26 species of 
marine mammals incidental to conducting, under a cooperative agreement 
with the National Science Foundation (NSF), a seismic survey in the 
Pacific Ocean and Caribbean Sea off Central America as part of the 
Subduction Factory (SubFac) initiative of NSF's MARGINS program from 
January-March, 2008. (The dates of the cruise were subsequently moved 
to February-April 2008.) The purpose of the research program was 
outlined in NMFS' notice of the proposed IHA (72 FR 71625, December 18, 
2007).

Description of the Activity

    The seismic survey will involve one source vessel, the R/V Marcus 
G. Langseth (Langseth), which will operate in two regions during the 
proposed survey: the Caribbean Sea and the Pacific Ocean. The Langseth 
will deploy an array of 36 airguns (6,600 in3) as an energy source and, 
at times, a receiving system consisting of a 6-km (3.7-mi) towed 
hydrophone streamer. The streamer will be towed at a depth of 5-8 m 
(16-26 ft). As the airgun array is towed along the survey lines, the 
hydrophone streamer will receive the returning acoustic signals and 
transfer the data to the on-board processing system. In the Caribbean 
region, the Langseth will also deploy Ocean Bottom Seismometers (OBSs) 
to receive the returning acoustic signals. In the Pacific Ocean, a 
second vessel, the R/V New Horizon, will deploy and retrieve the OBSs.
    For the first part of the cruise, the Langseth is expected to 
depart Puerto Limon, Costa Rica, on approximately February 16, 2008 for 
the study area in the Caribbean Sea (see Figure 1 in the application). 
The seismic survey will commence following the transit and deployment 
of the streamer and airgun array. Following approximately 25 days of 
surveying in the Caribbean Sea, all equipment will be recovered, and 
the vessel will return to Puerto Limon on approximately March 11, 2008. 
The vessel will then transit through the Panama Canal, likely taking on 
fuel in Panama. The second part of the survey will commence in the 
Pacific Ocean on approximately March 19, 2008 from Puerto Caldera, 
Costa Rica. The Pacific survey is estimated to last approximately 25 
days. The vessel is scheduled to arrive at Puerto Caldera on April 13, 
2008. The exact dates of the activities depend upon logistics, as well 
as weather conditions and/or the need to repeat some lines if data 
quality is substandard.
    The Central American SubFac survey will encompass the area from 
9.6[deg]-14[deg] N., 82[deg]-83.8[deg] W. in the Caribbean Sea and the 
area 8[deg]-11.5[deg] N., 83.6[deg]-88[deg] W. in the Pacific Ocean 
(see Figure 1 in the application). Water depths in the survey area 
range from less than 100 m (328 ft) to greater than 2,500 m (8,202 ft).
    The marine seismic survey will consist of approximately 2,149 km 
(1,335 mi) of unique survey lines: 753 km (468 mi) in the Caribbean and 
1,396 km (867 mi) in the Pacific (see Table 1 in the application). With 
the exception of two lines (D and E) located in shallow to 
intermediate-depth water, all lines will be shot twice, once at 
approximately a 50-m (164 ft; 20-s) shot spacing for multichannel 
seismic data and once at approximately a 200-m (656 ft; 80-s) shot 
spacing for OBS refraction data, for a total of approximately 3,980 km 
(2,473 mi) of survey lines (see Table 1 in the application). The 
approximate numbers of line kilometers expected to be surveyed in the 
Pacific and Caribbean in three different water depth categories are 
shown in Table 2 of the application. There will be additional 
operations associated with equipment testing, startup, line changes, 
and repeat coverage of any areas where initial data quality is 
substandard. There will be an additional 77 km (48 mi) of survey effort 
in the Pacific Ocean around Culebra off Nicoya Peninsula not reflected 
in Table 1 of L-DEO's application. These additional six transect lines 
will occur in water greater than 100 m (328 ft) deep, will not add any 
additional days to the cruise, and are not expected to increase the 
number of takes by harassment (see below).
    The New Horizon will be the dedicated OBS vessel during the Pacific 
part of the survey and will deploy and retrieve the OBSs. A combination 
of 85 OBSs (150 total deployments) will be used during the project. A 
total of 60 OBS deployments will take place in the Caribbean (from the 
Langseth), and 90 deployments will take place in the Pacific from the 
New Horizon.
    In addition to the operations of the airgun array, a 12-kHz Simrad 
EM120 multibeam echosounder will be operated from the Langseth 
continuously throughout the cruise. Also, a 3.5-kHz sub-bottom profiler 
(SBP) will be operated by the Langseth during most of the survey and 
during normal operations by the New Horizon.
    A more detailed description of the authorized action, including 
vessel and acoustic source specifications, was included in the proposed 
IHA notice (72 FR 71625, December 18, 2007).

Safety Radii

    L-DEO estimated the safety radii around their operations using a 
model and 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 notice (72 FR 71625, 
December 18, 2007) and Section I and Appendix A of L-DEO's application. 
Using the modeled distances and various correction factors, Table 1 
outlines 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 Distances (m)
       Source and Volume          Tow Depth (m)     Water Depth  -----------------------------------------------
                                                                      190 dB          180 dB          160 dB
----------------------------------------------------------------------------------------------------------------
Single Bolt airgun 40 in\3\      9                Deep            12              40              385
                                                  Intermediate    18              60              578
                                                  Shallow         150             296             1050
----------------------------------------------------------------------------------------------------------------

[[Page 9528]]

 
4 strings 36 airguns 6600 in\3\  9                Deep            300             950             6000
                                                  Intermediate    450             1425            6667
                                                  Shallow         2182            3694            8000
----------------------------------------------------------------------------------------------------------------
4 strings 36 airguns 6600 in\3\  12               Deep            340             1120            7400
                                                  Intermediate    510             1680            8222
                                                  Shallow         2473            4356            9867
----------------------------------------------------------------------------------------------------------------
Table 1. Predicted distances to which sound levels [gteqt]190, 180, and 160 dB re 1 microPa might be received in
  shallow (<100 m; 328 ft), intermediate (100-1,000 m; 328-3,280 ft), and deep (>1,000 m; 3,280 ft) water during
  the Central American SubFac survey.

Comments and Responses

    A notice of receipt of the L-DEO application and proposed IHA was 
published in the Federal Register on December 18, 2007 (72 FR 71625). 
During the comment period, NMFS received comments from the Marine 
Mammal Commission (MMC). Following are the comments from the MMC and 
NMFS' responses.
    MMC Comment 1: The MMC recommends that observations be made during 
all ramp-up procedures to gather data regarding its effectiveness as a 
mitigation measure.
    Response: The IHA requires that marine mammal observers (MMOs) on 
the Langseth make observations for 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; and
    (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, cloud cover, 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.
    MMC Comment 2: The MMC recommends that the monitoring period prior 
to the initiation of seismic activities and to the resumption of airgun 
activities after a power-down 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 (i.e., 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 20-40 
min); (2) in many cases MMOs are making observations during times when 
sonar is not being operated and will actually be observing the area 
prior to the 30-min observation period anyway; (3), many 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 its last random surfacing would be prior 
to the beginning of the required 30-min monitoring period.
    MMC Comment 3: The MMC recommends that NMFS provide additional 
justification for its proposed determination that the planned 
monitoring program will be sufficient to detect, with a high level of 
certainty, all marine mammals within or entering the identified safety 
radii.
    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 (PAM). This monitoring, along with 
the required mitigation measures (see below), will result in the least 
practicable adverse impact on the affected species or stocks and will 
result in a negligible impact on the affected species or stocks.
    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 2.4 nm, 4.4 km). 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). Night vision devices (NVDs) will be used in low light 
situations. Additionally, MMOs will have a good view in all directions 
around the entire vessel. Also, nearly 80 percent of the survey 
transect lines are in intermediate or deep water depths, where the 
safety radii are all less than 1 nm (1.9 km).
    In some cases, particularly in shallow water, chase boats will be 
deployed, if practicable. 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 3.7 km, 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. 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 (492 and 820 ft) using NVDs and about 30 m (98.4 
ft) with the naked eye. However, the PAM operates equally as 
effectively at night as during the day, especially for sperm whales and 
dolphins.
    MMC 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 the 
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, most marine mammals within or 
entering identified safety zones. This monitoring,

[[Page 9529]]

along with the required mitigation measures (see below), will result in 
the least practicable adverse impact on the affected species or stocks 
and will result in a negligible impact on the affected species or 
stocks.
    As mentioned above, the platform of the Langseth is high enough 
that, in good weather, MMOs can see out to 16.5 km (8.9 nm). The PAM 
has reliable detection rates out to 3 km (1.6 nm) and more limited 
ability out to 10s of km. The largest 180-dB safety radii (3.7 and 4.4 
km, 2 and 2.4 nm), which is the radii within which the Langseth is 
required to shut down if a marine mammal enters, are found when the 36-
gun array is operating in shallow water at 9 and 12 m (29.5 and 39 ft) 
tow depths, respectively. The species most likely to be encountered in 
the shallow waters off the coasts of Nicaragua and Costa Rica are 
bottlenose and pantropical spotted dolphins, which have relatively 
larger group sizes (2-15 animals for bottlenose dolphins but even 
higher in some areas of the survey, 20 or more animals per group for 
pantropical spotted dolphins), are not cryptic at the surface, and have 
relatively short dive times (5-12 minutes for bottlenose), all which 
generally make them easier to visually detect. Furthermore, the 
vocalizations of these species are easily detected by the PAM. Also, 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 (5.4 nm) from the vessel and 
identified them to species level at approximately 5 km (2.7 nm) from 
the vessel, though the bridge of that vessel was only 11 m (36 ft) 
above the water (vs. the Langseth, which is more than 17 m (55.8 ft) 
above sea level). All of the 180-dB safety radii for other water depths 
and tow depths and for the single 40 in\3\ airgun to be used during 
ramp-ups and power-downs (see below) are less than 2 km (1.1 nm).
    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, all of the safety 
radii in intermediate and deep water depths are smaller than 3 km (1.6 
nm) and fall easily within the reliable detection capabilities of the 
PAM.

Description of Marine Mammals in the Activity Area

    A total of 35 marine mammal species are known to or may occur in 
the study area off Central America, including 26 odontocete (dolphins 
and small and large toothed whales) species, six mysticete (baleen 
whales) species, two pinniped species, and the West Indian manatee. Six 
of the species that may occur in the project area are listed under the 
U.S. Endangered Species Act (ESA) as Endangered: the sperm, humpback, 
sei, fin, and blue whale and the manatee. The West Indian manatee is 
under the jurisdiction of the U.S. Fish and Wildlife Service (USFWS) 
and therefore is not considered further in this analysis. L-DEO 
requested and has been authorized to take 26 of these species. The 
remaining nine species are not expected to be encountered during the 
survey.
    Table 2 outlines the species, their habitat and abundance in the 
project area, and the estimated and authorized take levels. 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 (72 FR 71625, December 18, 2007) and may be 
found in L-DEO's application.

--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Abun. in NW                               Auth Take in Carib.
              Species                        Habitat               Atlantic\1\          Abun. in ETP\2\              Sea              Auth Take in ETP
--------------------------------------------------------------------------------------------------------------------------------------------------------
Odontocetes
Sperm whale (C,P)(Physeter          Pelagic                   13,190\a\              26,053\b\              3                      71
 macrocephalus)                                               4,804
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy sperm whale (C*,P)(Kogia      Deeper water off shelf    395\c\                 N.A.                   0                      0
 breviceps)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dwarf sperm whale (C*,P) (Kogia     Deeper waters off shelf   395\c\                 11,200\d\              0                      856
 sima)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Cuvier's beaked whale (C*,P)        Pelagic                   3,513\e\               20,000                 0                      302
 (Ziphius cavirostris)                                                               90,725\bb\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Longman's beaked whale (P?)         Pelagic                   N.A.                   291\bb\                0                      9
 (Indopacetus pacificus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy beaked whale (P) (Mesoplodon  Pelagic                   N.A.                   25,300\f\              0                      0
 peruvianus)                                                                         32,678\cc\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gingko-toothed beaked whale (P?)    Pelagic                   N.A.                   25,300\f\              0                      0
 (Mesoplodon ginkgodens)                                                             32,678\cc\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gervais' beaked whale               Pelagic                   N.A.                   N.A.                   4                      0
 (C?)(Mesoplodon europaeus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blainville's beaked whale (C*,P)    Pelagic                   N.A.                   25,300\f\              0                      29
 (Mesoplodon densirostris)                                                           32,678\cc\
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 9530]]

 
Rough-toothed dolphin (C?,P)        Mainly pelagic            2,223\g\               145,900                9                      954
 (Steno bredanensis)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tucuxi (C) (Sotalia fluviatilis)    Freshwater and coastal    49\h\                  N.A.                   0                      0
                                     waters                   705\i\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bottlenose dolphin (C,P) (Tursiops  Coastal, shelf and        43,951\j\              243,500                389                    2,380
 truncatus)                         pelagic                   81,588\k\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pantropical spotted dolphin (C?,P)  Coastal and pelagic       4,439                  2,059,100              37                     7,560
 (Stenella attenuata)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Atlantic spotted dolphin (C)        Coastal and shelf         50,978                 N.A.                   440                    0
 (Stenella frontalis)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spinner dolphin (C*,P) (Stenella    Coastal and pelagic       11,971\g\              1,651,100              0                      7,856
 longirostris)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Costa Rican spinner dolphin (P)     Coastal                   N.A.                   N.A.                   0                      3,358
 (Stenella l. centroamericana)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Clymene dolphin (C?) (Stenella      Pelagic                   6,086                  N.A.                   29                     0
 clymene)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Striped dolphin (C*,P) (Stenella    Coastal and pelagic       94,462                 1,918,000              31                     8,110
 coeruleoalba)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Short-beaked common                 Shelf and pelagic         N.A.                   3,093,300              0                      14,045
dolphin (P) (Delphinus delphis)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fraser's dolphin (C*,P)             Pelagic                   726\g\                 289,300                0                      144
 (Lagenodelphis hosei)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Risso's dolphin (C*,P) (Grampus     Shelf and pelagic         20,479                 175,800                0                      651
 griseus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Melon-headed whale (C*,P)           Pelagic                   3,451\g\               45,400                 0                      1,315
 (Peponocephala electra)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pygmy killer whale (C*,P) (Feresa   Pelagic                   6\l\                   38,900                 0                      231
 attenuata)                                                   408\g\
--------------------------------------------------------------------------------------------------------------------------------------------------------
False killer whale (C*,P)           Pelagic                   1,038\g\               39,800                 0                      479
 (Pseudorca crassidens)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale (C,P) (Orcinus orca)   Coastal                   133\g\                 8,500                  10                     17
                                                              6,600\m\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Short-finned pilot whale (C,P)      Pelagic                   31,139\n\              160,200\n\             36                     3,717
 (Globicephala macrorhynchus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale (C?,P) (Megaptera    Mainly nearshore          10,400\o\              NE Pacific 1,391\q\;   1                      4
 novaeangliae)                      waters and banks          11,570\p\              SE Pacific ~2,900\r\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minke whale (C*,P) (Balaenoptera    Coastal                   3,618s                 N.A.                   0                      0
 acutorostrata)                                               174,000t
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bryde's whale (C?,P) (Balaenoptera  Coastal and pelagic       35\g\                  13,000\u\              3                      68
 edeni)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sei whale (C*,P) (Balaenoptera      Pelagic                   12-13,000\v\           N.A.                   0                      0
 borealis)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Fin whale (C,P) (Balaenoptera       Pelagic                   2,814                  1,851\q\               1                      0
 physalus)                                                    30,000t
--------------------------------------------------------------------------------------------------------------------------------------------------------
Blue whale (C*,P) (Balaenoptera     Coastal, shelf, and       320\w\                 1,400                  0                      4
 musculus)                          pelagic

[[Page 9531]]

 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sirenian                            Freshwater and coastal    86\x\                  N.A.                   0                      0
West Indian manatee (C)              waters                   340\y\
 (Trichechus manatus manatus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pinnipeds
California sea lion (P) (Zalophus   Coastal                   N.A.                   237,000-244,000\z\     0                      0
 californianus)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gal[aacute]pagos sea lion (P?)      Coastal                   N.A.                   30,000\aa\             0                      0
 (Zalophus wollebaeki)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Table 2. The habitat, abundance, and requested take levels of marine mammals that may be encountered during the proposed Central American SubFac seismic
  survey off Central America. Note: Abun. = abundance, NWA = Northwest Alantic Ocean, P = may occur off Pacific coast of proposed project area, C = may
  occur off Caribbean coast of proposed project area, * = very unlikely to occur in proposed project area, ? = potentially possible but somewhat
  unlikely to occur in proposed project area, N.A. = Not available or not applicable.
\1\ For cetaceans, abundance estimates are given for U.S. Western North Atlantic stocks (Waring et al. 2006) unless otherwise noted.
\2\ Abundance estimates for the ETP from Wade and Gerrodette (1993) unless otherwise indicated.
\a\ g(o) corrected total estimate for the Northeast Atlantic, Faroes-Iceland, and the U.S. east coast (Whitehead 2002).
\b\ Whitehead 2002.
\c\ This estimate is for Kogia sp.
\d\ This abundance estimate is mostly for K. sima but may also include some K. breviceps.
\e\ This estimate is for Mesoplodon and Ziphius spp.
\f\ This estimate includes all species of the genus Mesoplodon from Wade and Gerrodette (1993).
\g\ This estimate is for the northern Gulf of Mexico.
\h\ Estimate from a portion of Cayos Miskito Reserve, Nicaragua (Edwards and Schnell 2001).
\i\ Estimate from the Canan[eacute]ia estuarine region of Brazil (Geise et al. 1999).
\j\ Estimate for the Western North Atlantic coastal stocks (North Carolina (summer), South Carolina, Georgia, Northern Florida, and Central Florida).
\k\ Estimate for the for the Western North Atlantic offshore stock.
\l\ Based on a single sighting.
\m\ Estimate for Icelandic and Faroese waters (Reyes 1991).
\n\ This estimate is for G. macrorhynchus and G. melas.
\o\ Estimate for the entire North Atlantic (Smith et al. 1999).
\p\ This estimate is for the entire North Atlantic (Stevick et al. 2001, 2003).
\q\ Carretta et al. 2007.
\r\ Felix et al. 2005.
\s\ This estimate is for the Canadian East Coast stock.
\t\ Estimate is for the North Atlantic (IWC 2007a).
\u\ This estimate is mainly for Balaenoptera edeni but may include some B. borealis.
\v\ Abundance estimate for the North Atlantic (Cattanach et al. 1993).
\w\ Minimum abundance estimate (Sears et al. 1990).
\x\ Antillean Stock in Puerto Rico only.
\y\ Antillean Stock in Belize (Reeves et al. 2002).
\z\ Estimate for the U.S. stock (Carretta et al. 2007).
\aa\ Reeves et al. 2002.
\bb\ Ferguson and Barlow 2001 in Barlow et al. 2006.
\cc\ This estimate includes all species of the genus Mesoplodon (Ferguson and Barlow 2001 in Barlow et al. 2006).

Potential Effects on Marine Mammals

    The effects of sounds from airguns might include one or more of the 
following: tolerance, masking of natural sounds, behavioral 
disturbances, and at least in theory, temporary or permanent hearing 
impairment, or non-auditory physical or physiological effects 
(Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 2007). 
However, it is unlikely that there would be any cases of temporary or 
especially permanent hearing impairment or any significant non-auditory 
physical or physiological effects. Also, behavioral disturbance is 
expected to be limited to relatively short distances.
    The notice of the proposed IHA (72 FR 71625, December 18, 2007) 
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 information on the behavioral reactions 
(or lack thereof) by all types of marine mammals to seismic vessels can 
be found in Appendix C (e) of L-DEO's application.
    The notice of the proposed IHA also included a discussion of the 
potential effects of the bathymetric sonar and the sub-bottom profiler. 
Because of the shape of the beams of these sources and their power, 
NMFS believes it unlikely that marine mammals will be exposed to either 
the bathymetric sonar or the SBP at levels at or above those likely to 
cause harassment. Further, NMFS believes that the brief exposure of 
cetaceans or pinnipeds to few signals from the multi-beam bathymetric 
sonar system are not likely to result in the harassment of marine 
mammals.

Estimated Take by Incidental Harassment

    The notice of the proposed IHA (72 FR 71625, December 18, 2007) 
included an in-depth discussion of the methods used to calculate the 
densities of the marine mammals in the area of the seismic survey and 
the take estimates. Additional information was included in L-DEO's 
application. A summary is included here.
    All anticipated takes authorized by this IHA are Level B harassment 
only, involving temporary changes in behavior. The two far right 
columns in Table 2, ``Auth Take in Carib. Sea'' and ``Auth Take in 
ETP'', display the numbers for which take is authorized in each ocean 
basin. Take calculations were based on maximum exposure estimates 
(based on maximum density estimates) vs. best estimates and are based 
on the 160-dB isopleth of a larger array of airguns. Given these 
considerations, the predicted number of marine mammals that might be 
exposed to sounds 160 dB may be somewhat overestimated.

[[Page 9532]]

    Extensive marine mammal surveys have been conducted in the eastern 
tropical Pacific over numerous years (e.g., Polacheck, 1987; Wade and 
Gerrodette, 1993; Kinsey et al., 1999, 2000, 2001; Ferguson and Barlow, 
2001; Smultea and Holst, 2003; Jackson et al., 2004; Holst et al., 
2005a; May-Collado et al., 2005). Therefore, for the Pacific portion of 
the proposed seismic survey, marine mammal density data were readily 
available. The most comprehensive data available for the region 
encompassing the proposed survey area are from Ferguson and Barlow 
(2001) and Holst et al. (2005a).
    For the Caribbean portion of the Central American SubFac program, 
we were unable to find published data on marine mammal densities in or 
immediately adjacent to the seismic survey area. The closest 
quantitative surveys were conducted in the southeast Caribbean (Swartz 
and Burks, 2000; Swartz et al., 2001; Smultea et al., 2004). Most of 
the survey effort by Swartz and Burks (2000) and Swartz et al. (2001) 
took place during March and April near the islands on the east side of 
the Caribbean Sea and near the north and northeast coasts of Venezuela 
in water depths <1,000 m (3,280 ft). Survey data from Smultea et al. 
(2004) were collected north of Venezuela during April-June in 
association with a previous L-DEO seismic survey. The L-DEO survey will 
occur from February-March in the western Caribbean Sea, a location and 
time of year in which the species densities are likely different from 
those during the above-mentioned surveys in the southeast Caribbean, 
but these surveys are the best available data at this time.
    Except for dwarf sperm whales, the per-species take estimates fall 
within 3 percent (dwarf sperm whale takes are 7.64 percent) of the 
numbers estimated to be present during a localized survey in the 
Pacific Ocean off the coasts of Costa Rica and Nicaragua, and the 
affected species range far beyond the Pacific Ocean (i.e., the 
abundance of the species is notably larger). Therefore, NMFS believes 
that the estimated take numbers for these affected species are 
relatively small.
    Similarly, the per-species take estimates are less than 1 percent 
(except killer (7.52 percent) and Bryde's (8.57 percent) whales) of the 
numbers estimated to be present during a localized survey in the 
Caribbean Sea off the coasts of Costa Rica and Nicaragua, and the 
species range far beyond the Caribbean (i.e., the abundance of the 
species is notably larger). Therefore, NMFS believes that the estimated 
take numbers for these species are relatively small.
    No pinnipeds are expected to be encountered in the Caribbean, and 
the likelihood of encountering sea lions or other pinnipeds in the 
Pacific study area is also very low. No take of any pinniped species is 
authorized.

Potential Effects on Habitat

    A detailed discussion of the potential effects of this action on 
marine mammal habitat, including physiological and behavioral effects 
on marine fish and invertebrates, was included in the notice of the 
proposed IHA (72 FR 71625, December 18, 2007). Based on the discussion 
in the proposed IHA and the nature of the activities (limited 
duration), 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. Similarly, any effects to food sources are expected to be 
negligible.

Monitoring

Vessel-based Visual Monitoring

    Vessel-based marine mammal visual observers (MMVOs) will be based 
aboard the seismic source vessel and will watch for marine mammals near 
the vessel during daytime airgun operations and during start-ups of 
airguns at night. MMVOs will also watch for marine mammals near the 
seismic vessel for at least 30 minutes prior to the start of airgun 
operations after an extended shutdown of the airguns. When feasible, 
MMVOs will also make observations during daytime periods when the 
seismic system is not operating for comparison of animal abundance and 
behavior. Based on MMVO observations, airguns will be powered down, or 
if necessary, shut down completely (see below), when marine mammals are 
detected within or about to enter a designated safety radius. The MMVOs 
will continue to maintain watch to determine when the animal(s) are 
outside the safety radius, and airgun operations will not resume until 
the animal has left that zone. The safety radius is a region in which a 
possibility exists of adverse effects on animal hearing or other 
physical effects.
    During seismic operations off Central America, at least three 
observers will be based aboard the Langseth. MMVOs will be appointed by 
L-DEO with NMFS concurrence. At least one MMVO, and when practical two, 
will monitor the safety radii for marine mammals during daytime 
operations and nighttime startups of the airguns. MMVO(s) will be on 
duty in shifts of duration no longer than 4 hours. The crew will also 
be instructed to assist in detecting marine mammals and implementing 
mitigation requirements (if practical).
    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. During daytime, the MMVO(s) 
will scan the area around the vessel systematically with reticle 
binoculars (e.g., 7x50 Fujinon), Big-eye binoculars (25x150), and with 
the naked eye. During darkness, NVDs will be available (ITT F500 Series 
Generation 3 binocular-image intensifier or equivalent). Laser 
rangefinding binoculars (Leica LRF 1200 laser rangefinder or 
equivalent) will be available to assist with distance estimation.

Passive Acoustic Monitoring

    PAM will take place to complement the visual monitoring program. 
Visual monitoring typically is not 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. 
Acoustic monitoring can be used in addition to visual observations to 
improve detection, identification, localization, and tracking of 
cetaceans. It is only useful when marine mammals call, but it can be 
effective either by day or by night and does not depend on good 
visibility. The acoustic monitoring will serve to alert visual 
observers (if on duty) when vocalizing cetaceans are detected. It will 
be monitored in real time so visual observers can be advised when 
cetaceans are detected. When bearings (primary and mirror-image) to 
calling cetacean(s) are determined, the bearings will be relayed to the 
visual observer to help him/her sight the calling animal(s).
    SEAMAP (Houston, Texas) will be used as the primary acoustic 
monitoring system. This system was also used during several previous L-
DEO seismic cruises (e.g., Smultea et al., 2004, 2005; Holst et al., 
2005a,b). A description of the PAM system was given in the notice of 
the proposed IHA (72 FR 71625, December 18, 2007).
    While the Langseth is in the seismic survey area, the towed 
hydrophone array will be monitored 24 hours per day while at the survey 
area during airgun operations and also during most periods when the 
Langseth is underway with the airguns not operating. One MMO will 
monitor the acoustic detection system at any one time, by listening to 
the signals from two

[[Page 9533]]

channels via headphones and/or speakers and watching the real time 
spectrographic display for frequency ranges produced by cetaceans. MMOs 
monitoring the acoustical data will be on shift for 1-6 hours. 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 cetacean vocalization is detected, the acoustic MMO will, if 
visual observations are in progress, contact the MMVO immediately to 
alert him/her to the presence of the vocalizing marine mammal(s). 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, date, time when first and 
last heard and whenever any additional information was recorded, 
position and water depth when first detected, bearing if determinable, 
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 
for further analysis.

MMVO Data and Documentation

    MMVOs will record data to estimate the numbers of marine mammals 
exposed to various received sound levels and to document any apparent 
disturbance reactions or lack thereof. Data will be used to estimate 
the numbers of mammals potentially ``taken'' by harassment. They will 
also provide information needed to order a power-down or shutdown of 
airguns when marine mammals are within or near the relevant safety 
radius. 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 including responses to ramp-up), and 
behavioral pace.
    (2) Time, location, heading, speed, activity of the vessel 
(including number of airguns operating and whether in state or ramp-up, 
power-down, or full power), sea state, visibility, cloud cover, and sun 
glare.
    The data listed under (2) will also be recorded at the start and 
end of each observation watch and during a watch, whenever there is a 
change in one or more of the variables.
    All mammal observations, as well as information regarding airgun 
power down and shutdown, will be recorded in a standardized format. 
Data accuracy will be verified by the MMVOs at sea, and preliminary 
reports will be prepared during the field program and summaries 
forwarded to the operating institution's shore facility and to NSF 
weekly or more frequently. MMVO observations will provide the following 
information:
    (1) The basis for decisions about powering down or shutting down 
airgun arrays.
    (2) Information needed to estimate the number of marine mammals 
potentially 'taken by harassment', which must be reported to NMFS.
    (3) Data on the occurrence, distribution, and activities of marine 
mammals in the area where the seismic study is conducted.
    (4) Data on the behavior and movement patterns of marine mammals 
seen at times with and without seismic activity.

Mitigation

    Mitigation and monitoring measures proposed to be implemented for 
the proposed seismic survey have been developed and refined during 
previous L-DEO seismic studies and associated environmental assessments 
(EAs), IHA applications, and IHAs. The mitigation and monitoring 
measures described herein represent a combination of the procedures 
required by past IHAs for other similar projects and on recommended 
best practices in Richardson et al. (1995), Pierson et al. (1998), and 
Weir and Dolman (2007). The measures are described in detail below.
    Required mitigation measures include: (1) speed or course 
alteration, provided that doing so will not compromise operational 
safety requirements; (2) power-down procedures; (3) shutdown 
procedures; (4) ramp-up procedures; and (5) minimizing approaches to 
slopes and submarine canyons, if possible, because of sensitivity of 
beaked whales.
    Speed or Course Alteration - If a marine mammal is detected outside 
the safety radius but is likely to enter it based on relative movement 
of the vessel and the animal, then if safety and scientific objectives 
allow, the vessel speed and/or course will be adjusted to minimize the 
likelihood of the animal entering the safety radius. Major course and 
speed adjustments are often impractical when towing long seismic 
streamers and large source arrays, thus for surveys involving large 
sources, alternative mitigation measures are required.
    Power-down Procedures - A power-down involves reducing the number 
of operating airguns, typically to a single airgun (e.g., 40 in\3\), to 
minimize the safety radius, so that marine mammals are no longer in or 
about to enter this zone. A power-down of the airgun array to a reduced 
number of operating airguns may also occur when the vessel is moving 
from one seismic line to another. The continued operation of at least 
one airgun is intended to alert marine mammals to the presence of the 
seismic vessel in the area.
    If a marine mammal is detected outside the safety radius but is 
likely to enter it, and if the vessel's speed and/or course cannot be 
changed, the airguns will be powered down to a single airgun before the 
animal is within the safety radius. Likewise, if a mammal is already 
within the safety radius when first detected, the airguns will be 
powered down immediately. If a marine mammal is detected within or near 
the smaller safety radius around that single airgun (see Table 1), all 
airguns will be shutdown (see next subsection).
    Following a power down, airgun activity will not resume until the 
marine mammal is outside the safety radius for the full array. The 
animal will be considered to have cleared the safety radius if it:
    (1) Is visually observed to have left the safety radius; or
    (2) Has not been seen within the safety radius for 15 minutes in 
the case of small odontocetes and pinnipeds; or
    (3) Has not been seen within the safety radius for 30 minutes in 
the case of mysticetes and large odontocetes, including sperm, pygmy 
sperm, dwarf sperm, killer, and beaked whales.
    Following a power-down and subsequent animal departure as above, 
the airgun array will resume operations following ramp-up procedures 
described below.
    Shutdown Procedures - The operating airgun(s) will be shutdown if a 
marine mammal is detected within the safety radius of a single 40 in3 
airgun while the airgun array is at full volume or during a power down. 
Airgun activity will not resume until the marine mammal has cleared the 
safety radius or until the MMVO is confident that the animal has left 
the vicinity of the vessel. Criteria for judging that the animal has 
cleared the safety radius will be as described in the preceding 
subsection.
    Ramp-up Procedures - A ramp-up procedure will be followed when the 
airgun array begins operating after a specified-duration period without

[[Page 9534]]

airgun operations or when a power-down has exceeded that period. For 
the present cruise, this period would be approximately 8 min. This 
period is based on the modeled 180-dB radius for the 36-airgun array 
(see Table 1) in relation to the planned speed of the Langseth while 
shooting in deep water. Similar periods (approximately 8-10 min) were 
used during previous L-DEO surveys.
    Ramp-up from a state of no airgun operations will begin with the 
smallest airgun in the array (40 in\3\). Airguns will be added in a 
sequence such that the source level of the array will increase in steps 
not exceeding 6 dB per 5-minute period over a total duration of 
approximately 20-40 min. Ramp-up from a reduced power state, such as 
during maintenance of an airgun string while the remaining string 
continues to fire would include the start-up of the returned string. 
During ramp-up, the MMVOs will monitor the safety radius, and if marine 
mammals are sighted, a course/speed change, power-down, or shutdown 
will be implemented as though the full array were operational.
    Initiation of ramp-up procedures from shutdown requires that the 
full safety radius must be visible by the MMVOs, whether conducted in 
daytime or nighttime. This requirement will effectively preclude start 
ups at night or in thick fog because the outer part of the safety 
radius for that array will not be visible during those conditions. 
Ramp-up is allowed from a power-down under reduced visibility 
conditions only if at least one airgun (e.g., 40 in\3\ or similar ) has 
operated continuously throughout the survey without interruption, 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 radius 
during the day or close to the vessel at night.
    Minimize Approach to Slopes and Submarine Canyons - Although 
sensitivity of beaked whales to airguns is not known, they appear to be 
sensitive to other sound sources (e.g., mid-frequency sonar). Beaked 
whales tend to concentrate in continental slope areas and in areas 
where there are submarine canyons. There are no submarine canyons 
within or near the study area. Three of the transect lines are on the 
continental slope, which accounts for only a small portion of the 
proposed study area (207 km; 128.6 mi) and a minimal amount of time (30 
hours).

Reporting

    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 sightings of marine mammals 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, all marine 
mammal sightings (dates, times, locations, activities, associated 
seismic survey activities), and estimates of the amount and nature of 
potential ``take'' of marine mammals by harassment or in other ways.

Endangered Species Act (ESA)

    Pursuant to section 7 of the ESA, NSF has consulted with the NMFS, 
Office of Protected Resources, Endangered Species Division 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. NMFS has issued a Biological Opinion 
(BiOp), which concluded that the proposed action and issuance of an IHA 
are not likely to jeopardize the continued existence of blue, fin, 
humpback and sperm whales and green, hawksbill, leatherback, 
loggerhead, and olive ridley sea turtles. The BiOp also concluded that 
the proposed action would have no effect on critical habitat since none 
has been designated within the action area. The BiOp also made a not 
likely to be adversely affected finding for sei whales, Kemp's ridley 
sea turtles, and elkhorn and staghorn corals. An incidental take 
statement (ITS) will be issued for the take of blue, fin, humpback, and 
sperm whales and green, hawksbill, leatherback, loggerhead, and olive 
ridley sea turtles. Relevant Terms and Conditions of the ITS have been 
incorporated into the IHA.
    NSF and L-DEO made a ``no effects'' determination for this seismic 
survey regarding the West Indian manatee. The USFWS concurred with this 
determination since activities would occur at least 8 km (5 mi) from 
shore in water depths greater than 20 m (65.6 ft). Also, no support 
vessels would be sent from shore during the cruise. Based on these 
parameters, a USFWS consultation was not required for this action.

National Environmental Policy Act (NEPA)

    NSF prepared an Environmental Assessment of a Marine Geophysical 
Survey by the R/V Marcus G. Langseth off Central America, January-March 
2008. NMFS has adopted NSF's EA and issued a Finding of No Significant 
Impact for the issuance of the IHA.

Determinations

    NMFS has determined that the impact of conducting the seismic 
survey in the Pacific Ocean and Caribbean Sea off Central America may 
result, at worst, in a temporary modification in behavior (Level B 
Harassment) of small numbers of 26 species of cetaceans. Further, this 
activity is expected to result in a negligible impact on the affected 
species or stocks. The provision requiring that the activity not have 
an unmitigable adverse impact on the availability of the affected 
species or stock for subsistence uses does not apply for this action.
    This negligible impact determination is supported by: (1) the 
likelihood that, given sufficient notice through relatively slow ship 
speed, marine mammals are expected to move away from a noise source 
that is annoying prior to it becoming potentially injurious; (2) the 
fact that marine mammals would have to be closer than 40 m (131 ft) in 
deep water, 60 m (197 ft) at intermediate depths, or 296 m (971 ft) in 
shallow water when a single airgun is in use from the vessel to be 
exposed to levels of sound (180 dB) believed to have even a minimal 
chance of causing TTS; (3) the fact that marine mammals would have to 
be closer than 950 m (0.5 nm) in deep water, 1,425 m (0.8 nm) at 
intermediate depths, and 3,694 m (2 nm) in shallow water when the full 
array is in use at a 9 m (29.5 ft) tow depth from the vessel to be 
exposed to levels of sound (180 dB) believed to have even a minimal 
chance of causing TTS; (4) the fact that marine mammals would have to 
be closer than 1,120 m (0.6 nm) in deep water, 1,680 m (0.9 nm) at 
intermediate depths, and 4,356 m (2.4 nm) in shallow water when the 
full array is in use at a 12 m (39 ft) tow depth from the vessel to be 
exposed to levels of sound (180 dB) believed to have even a minimal 
chance of causing TTS; (5) the likelihood that marine mammal detection 
ability by trained observers is good at those distances from the 
vessel; (6) the use of PAM, which is effective out to 10s of km, will 
assist in the detection of vocalizing marine mammals at greater 
distances from the vessel; and (7) the incorporation of other required 
mitigation measures (i.e., ramp-up, power-down, and shutdown). As a 
result, no take by injury or death is anticipated, and the potential 
for temporary or permanent hearing impairment is very low and will be

[[Page 9535]]

avoided through the incorporation of the required mitigation measures.
    While the number of potential incidental harassment takes will 
depend on the distribution and abundance of marine mammals in the 
vicinity of the survey activity, the number of potential harassment 
takings is estimated to be small, a small percent of any of the 
estimated population sizes, and has been mitigated to the lowest level 
practicable through incorporation of the measures mentioned previously 
in this document.

Authorization

    As a result of these determinations, NMFS has issued an IHA to L-
DEO for conducting a marine geophysical survey in the Pacific Ocean and 
Caribbean Sea off Central America from February-April, 2008, provided 
the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated.

    Dated: February 14, 2008.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. E8-3256 Filed 2-20-08; 8:45 am]
BILLING CODE 3510-22-S