[Federal Register Volume 67, Number 98 (Tuesday, May 21, 2002)]
[Notices]
[Pages 35793-35799]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-12718]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 010302E]


Small Takes of Marine Mammals Incidental to Specified Activities; 
Seismic Hazard Investigations in Washington State

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

ACTION: Notice of issuance of an incidental harassment authorization.

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SUMMARY: In accordance with provisions of the Marine Mammal Protection 
Act (MMPA) as amended, notification is hereby given that an Incidental 
Harassment Authorization (IHA) to take small numbers of marine mammals 
by harassment incidental to collecting marine seismic reflection data 
to investigate the earthquake hazard in the Straits of Georgia region 
of Washington State by the U.S. Geological Survey (USGS) during May, 
2002.

DATES: This authorization is effective from April 30, 2002, through 
September 30, 2002.

ADDRESSES: A copy of the application and an Environmental Assessment 
(EA) may be obtained by writing to Donna Wieting, Chief, Marine Mammal 
Conservation Division, Office of Protected Resources, NMFS, 1315 East-
West Highway, Silver Spring, MD 20910-3225, or by telephoning the 
contact listed below.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2055, ext 128.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Permission may be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s) and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses, and if the permissible methods of taking 
and requirements pertaining to the monitoring and reporting of such 
takings are set forth. NMFS has defined "negligible impact" 
in 50 CFR 216.103 as "...an impact resulting from the specified 
activity that cannot be reasonably expected to, and is not reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival."
    Subsection 101(a)(5)(D) of the MMPA established an expedited 
process by which citizens of the United States can apply for an 
authorization to incidentally take small numbers of marine mammals by 
harassment. The MMPA defines "harassment" as:
    any act of pursuit, torment, or annoyance which (a) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild; or (b) 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.
    Subsection 101(a)(5)(D) establishes a 45-day time limit for 
NMFS review of an application followed by a 30-day public notice 
and comment period on any proposed authorizations for the incidental 
harassment of small numbers of marine mammals. Within 45 days of the 
close of the comment period, NMFS must either issue or deny issuance of 
the authorization.

Summary of Request

    In May, 2002, the USGS, in cooperation with the Geological Survey 
of Canada and the University of Victoria, will collect marine seismic 
reflection data to investigate the earthquake hazards in the Straits of 
Georgia. For approximately 2 to 4 days this research will be in U.S. 
waters and about 17 to 19 days will be in Canadian waters. Geological 
features around the Straits of Georgia that might produce earthquakes 
lie obscured beneath water, urban areas, forest, and thick glacial 
deposits. As a result, investigators must use sound waves that are 
produced by either a single airgun or more usually an array of airguns 
to indirectly view these features. Because seismic noise from the 
proposed survey's airguns could potentially affect marine mammals due 
to disturbance by sound (i.e., acoustic harassment), an IHA under the 
MMPA is warranted.
    Throughout western Washington state and southwest British Columbia 
(BC), geological faults that might produce earthquakes lie hidden 
beneath the dense forest and the waters of Puget Sound and the Strait 
of Georgia. Although some faults are known from limited exposures on 
land and from marine seismic surveys, such as the Lummi Island and 
Outer Islands faults (see Figure 1 in the USGS application), more may 
have eluded detection in this little-studied area. Furthermore, the 
amount of recent (<50,000 years) motion on these faults, if any, is 
unknown. Estimating the frequency and sizes of earthquakes on both the 
known and unknown faults is crucial to understanding the earthquake 
risk to the cities of Bellingham and Anacortes, WA to Vancouver and 
Victoria, BC and to the more rural parts of the region. For more 
detailed information on the geological faults in this area, please 
refer to the USGS application.
    Seismic reflection data will be collected during May, 2002 by the 
Canadian research vessel J. P. Tully. Seismic profiling will be done by 
towing a 600-m (1,968.5-ft) long hydrophone streamer for 
sensing and recording pressure changes from the airgun echos. The 
streamer will be towed at a depth of 5 m (16.4 ft). Near the forward 
end of the streamer, an airgun will be towed about 10 m (32.8 ft) 
behind the ship at a depth of about 5 m (16.4 ft). The hydrophone 
streamer, which is connected to a computer recording system, will 
record echos coming from the strata beneath the sea bottom. These 
recordings will be computer-processed to create an image of the 
subsurface strata, including any faults that are crossed during the 
profiling. The seismic operation will operate 24 hours/day while in 
U.S. waters and will be traveling at a speed of 6 to 8 knots (6.9 to 
9.2 miles/hr; 11.1 to 14.8 km/hr).
    The sound source will be either a single, 120 inch\3\ airgun or, 
more likely, a small array of airguns consisting of two 40- in3 and two 
20-in\3\ guns being fired within several milliseconds (1/1000 
second) of each other. The source will be chosen after tests at the 
beginning of the cruise. Either way, this sound source, as measured by 
the volume of the chamber, is only 2 percent of the size of the airgun 
array

[[Page 35794]]

used in the USGS survey conducted in 1998 in Puget Sound (see 63 FR 
2213, January 14, 1998). Both of the USGS' potential sources for 
this activity will produce similar levels of sound pressure, which is 
estimated to be about 225 dB. An array of small airguns increases the 
frequency of the sound over that from a single gun, and an array better 
directs the sound downward. This array has been used previously in the 
inland waters of Canada (Reidel et al., 1999), and the characteristics 
of this sound source have been measured (see Figure 3 in the USGS 
application).
    The airgun does not emit a prolonged sound source; rather, it emits 
an impulsive noise burst (<10 milliseconds) with a peak-to-peak (P-
P) sound pressure level (SPL) estimated to be between 220 dB and 230 
dB. The USGS best estimate is that the source will have an SPL of about 
225 dB (P-P). This compares to an estimated SPL of 240 dB (P-P) for the 
6730 inch\3\ airgun array used in the 1998 Puget Sound seismic survey 
project (Fisher, 1997). The airgun will be fired almost continuously 3 
to 6 times per minute.
    There is about a 16-dB difference between measuring the P-P 
sound pressure and the more commonly used root-mean-square (RMS) 
measurement for assessing sound pressure impacts on marine mammals (6 
dB converts P-P to peak-to-zero values, and an additional 10 dB 
converts peak-to-zero to RMS values). NMFS' criteria for safety radii 
based on pressure measurements are based on the RMS or the average 
received level over the duration of the sound pulse. These conversions 
mean that the USGS airgun array will be approximately equivalent to a 
source with a RMS sound pressure of about 204 to 214 dB (relative to 1 
ï¿½Pa), with a best estimate being about 209 dB (RMS). This 
compares with the continuous noise from freighters and other ship 
traffic in the area, which is estimated to be 150 to 205 dB RMS 
(Richardson et al., 1995).
    The frequency spectrum of the sound emission was measured when the 
array was used in a previous study (Reidel et al., 1999). The airgun's 
energy is concentrated below 200 Hz, with a rapid decrease in amplitude 
with increasing frequency between 200 and 400 Hz. Frequencies above 400 
Hz have amplitudes that are less than 10 percent of the lower 
frequencies. Frequencies below 1,000 Hz (1 kHz) are considered low 
frequency (LF).

Comments and Responses

    A notice of receipt of the application and proposed authorization 
was published on February 7, 2002 (67 FR 5792), and a 30-day 
public comment period was provided on the application and proposed 
authorization. Comments were received from the Marine Mammal Commission 
(MMC) and Lifeforce.
    Comment 1: Lifeforce advises that all activities that could produce 
any undetermined impact on marine wildlife must not be permitted. This 
should be of special concern regarding the southern community of 
resident orca. They are in the planned research area during April and 
May. In 2001 all three pods were present in May. The abundance of orcas 
is high. Noise from these tests could interrupt foraging, socializing, 
and resting periods. These types of disturbance are believed to 
jeopardize the survival of this population. The population was recently 
designated as an endangered species by the Committee on the Status of 
Endangered Wildlife in Canada (COSEWIC) and the U.S. Government is 
considering similar action.
    Response: The proposed authorization notice did not state that 
impacts could not be determined, but that impacts from noise were 
variable. If NMFS finds that the taking will be small, have a 
negligible impact on the species or stock(s) of affected marine 
mammals, and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses, the 
taking by incidental harassment can be authorized under section 
101(a)(5)(D) of the MMPA. Due to the fairly low SPL for the single 
airgun or small airgun array (approximately 209 dB RMS) and the 
mitigation monitoring required under the IHA, marine mammal injury and 
mortality is unlikely. Impacts, therefore, would be limited to Level B 
harassment. Because behavioral reactions to the seismic airgun sounds 
and/or the USGS vessel could occur, the USGS applied for an IHA under 
the MMPA. Provided certain findings are made, as here, the MMPA allows 
marine mammals to be harassed, injured or killed incidental to 
conducting maritime activities.
    The killer whale, however, appears to be fairly insensitive to LF 
sounds, with hearing ability approximately 100-140 dB for LF-
sound (Richardson et al., 1995). This means that it would be unlikely 
for killer whales to behaviorally respond to the sounds unless the 
sounds are about 20 dB or higher above those levels. For the airgun(s) 
planned to be used by this activity, this means being close to the 
source. In addition, due to the short duration of the activity under 
consideration here and the mitigation required to be conducted, it is 
unlikely that impacts on killer whales would cause more than a short-
term disturbance on a very few animals and would therefore have a 
negligible impact on the killer whale population or stock.
    On August 13, 2001 (66 FR 42499), NMFS announced that a petition to 
list the eastern North Pacific southern resident stock of killer whales 
as endangered or threatened species under the Endangered Species Act 
(ESA) and to designate critical habitat for this stock under the ESA 
presented substantial scientific information indicating that a listing 
may be warranted and would initiate an ESA status review. In accordance 
with section 4(b)(3)(B) of the ESA, NMFS is completing its status 
review on this stock.
    Comment 2: There has been evidence from necropsies on marine 
mammals that damage to auditory systems can be caused by loud noises 
and can be fatal. As in humans, hearing impairment can be caused by 
short term and/or long term exposure to loud noises. Therefore, any 
exposure from these tests could have an immediate or accumulative 
impact.
    Response: Injury to both auditory and non-auditory organs can be 
caused by loud impulse noise and by explosions as noted in the proposed 
authorization document and this document. However, the acoustic sources 
proposed for use by this activity are unlikely to result in an SPL 
sufficient to cause Level A harassment (i.e., injury). In addition, 
Diercks et al. (1971), as reported in Richardson et al. (1995) recorded 
killer whale echo-location clicks at 180 dB in the 12 to 25-kHz 
frequency. For the proposed airgun, 180 dB (P-P) is approximately 50 m 
(32.8 ft) from the source, at which distance the SPL on an RMS basis 
would be approximately 164 dB (180 dB would be less than 10 m (32.8 ft) 
from the acoustic source). Therefore, since marine mammals are unlikely 
to be injured by their own vocalizations or vocalizations of 
conspecifics, it is unlikely that animals would be injured by sounds 
from this acoustic source unless the animal is significantly closer to 
the airgun than 10 m (32.8 ft). Finally, because the activity will be 
less than 19 days long, no long-term impacts are anticipated.
    Comment 3: Seals should be regarded as any other species in the 
mitigation and monitoring plans. It is known that seal bombs and noise 
deterrents used on fish farms frighten seals and can cause hearing 
damage. Lifeforce assumes that continuous noise from airguns would 
create similar problems.
    Response: Under section 101(a)(5)(D) of the MMPA, it is NMFS' 
responsibility to ensure that the impact on marine

[[Page 35795]]

mammals due to an activity is reduced to the lowest level practicable. 
In reviewing the information available, NMFS has determined that it is 
not practicable to require applicants to delay surveys in order to 
provide more protection for curious seals than has been proposed by the 
applicant, unless the animal indicates a significant adverse effect 
(see response to comment (RTC) 4 in this document). Delays due to 
shutdowns lengthen the time necessary for completing surveys, requiring 
additional survey time and resulting in a potential increase in impacts 
on more sensitive marine mammal species, and raise the potential for 
either increased costs for conducting surveys or continuing surveys in 
future years. As mentioned in this document and in prior Federal 
Register notices, seals and sea lions are believed to be less likely to 
be harmed by underwater noise than cetaceans, and have even been 
observed swimming in the bubbles of large seismic airgun arrays, a 
source significantly more powerful than the one proposed for use by 
this activity. For impulse noise such as the one under consideration 
here, it has been determined through scientific workshops that 
pinnipeds would need to be closer than 190 dB (RMS) before there is 
even the potential for injury. Because an SPL of 190 dB would be within 
about 5 m (16.4 ft) of the airgun, a requirement under the IHA of a 
100-m (328-ft) shutdown is unnecessary for those seals and sea 
lions approaching the airgun.
    Comment 4: Regarding monitoring the impact on marine mammals by the 
activity, the MMC believes the program (if funded) is adequate to 
verify that animals are taken only as authorized. The MMC notes 
however, that, in monitoring pinniped approaches to the active airgun 
array, transmissions be suspended if there is any indication that the 
animals are being adversely affected.
    Response: NMFS concurs and has made that recommendation a part of 
the IHA. However, these seals and sea lions need to be actively 
approaching the vessel (itself moving forward at about 3-5 knots) 
from the side of the vessel or the stern, meaning that the animal is 
voluntarily approaching a noise source that is increasing in strength 
as the animal gets closer. Therefore, if a pinniped approaches the USGS 
vessel, the IHA requires the USGS to monitor the interaction to ensure 
the animal does not show signs of distress. If the pinniped(s) show 
obvious distress, the USGS is to suspend airgun operations until the 
pinniped moves outside of the safety zone and to continue to conduct 
observations on effects on all pinnipeds after the airgun is again 
powered up.
    Comment 5: When cetaceans, such as orcas, gray whales, humpback 
whales, minke whales and other slower moving cetaceans are sighted at 
any distance, the tests should be suspended until they are a safe 
distance from, and are clearly moving away from the test site. When 
faster dolphins and porpoises are sighted at any distance near the 
safety zone the tests should be suspended until they are clearly 
heading in a direction away from the research activity.
    Response: The USGS has recommended, and NMFS has adopted, shutdown 
criteria for this activity at 100 m (328 ft) for all cetaceans and 
pinnipeds. At 100 m (328 ft), the SPL from the proposed airgun(s) will 
be approximately 170 dB (P-P) or 154 dB (RMS). This shutdown distance 
is significantly greater than is necessary to protect marine mammals 
from the potential for injury. As noted in RTC 3, suspension of 
activities whenever a marine mammal is sighted is not practical due to 
the potential number of shutdowns that could be required, and is not 
necessary because of the low SPL of the acoustic source.
    Comment 6: Tests during darkness must not be permitted. Proper 
monitoring of marine wildlife at night is impossible and may not meet 
MMPA requirements. The use of night vision equipment only works if you 
know where to look and scanning the areas would miss marine wildlife 
during their dive periods. By the time they are spotted, they could be 
within the safety zone. Operation should only be allowed from sunrise 
to sunset.
    Response: During nighttime, observers are required to monitor a 
minimum of 50-m (164-ft) radius around the source whenever 
the airgun or small airgun array is powered up, to protect marine 
mammals. This distance is sufficient to ensure that marine mammals are 
detected prior to getting close enough to the airgun array to be 
injured. As discussed in the proposed authorization, suspension of 
night-time operations is impractical and costly to the USGS, and it may 
not result in reduced impacts to marine mammals by extending surveys 
either into a period of greater marine mammal abundance or into a 
future year when funding and ship time become available, or both. NMFS 
believes that because the vessel is underway, resulting in a de-facto 
ramp-up for marine mammals at distances forward of the vessel, no 
marine mammals will be injured by the airgun or small airgun array. 
However, because a mitigation requirement of the IHA is for the safety 
zone to be monitored for 15 minutes prior to the time the source is 
turned on, if the source is powered up at night or in inclement 
weather, the entire 50-m (164-ft) safety zone needs to be 
visible to the biological observers. Otherwise, the source must remain 
below 160 dB re 1 micro Pa-m (RMS), until sufficient light is available 
to observe the safety zone(s). Alternatives to night-vision equipment 
would include lighting the safety zone with high intensity lights or 
use of infra-red scopes, which operate differently than most light-
enhancement devices. Infra-red scopes were tested by biologists in 1997 
and found to be useful in detecting marine mammals at night; however, 
they are expensive to rent or purchase and may not be warranted for 
this short duration survey.
    Comment 7: The applicants have stated that their monitoring plans 
would probably not meet MMPA requirements. They state that funding 
would be required to meet adequate monitoring objectives.
    Response: The USGS will be capable of conducting the monitoring 
program required under the IHA for this activity.
    Comment 8: Lifeforce recommends that observers on the seismic team 
should have experience and training in spotting marine wildlife.
    Response: In order to monitor shutdown areas and to make 
observations on marine mammal behavior, at least one observer on watch 
needs to be trained in making at-sea observations of marine mammals. 
For this activity, the USGS has contracted with a private company to 
provide a minimum of three biological observers. In addition, 
crewmembers will also assist in watching for marine mammals.
    Comment 9: The MMC recommends that NMFS advise the USGS that, if 
there is any indication that other types of taking (e.g., mortalities) 
may be occurring, survey activities be suspended while NMFS considers 
whether an authorization under section 101(a)(5)(A) is needed.
    Response: Because the survey time is limited to 2 days in U.S. 
waters, suspension of an IHA would likely result in termination of that 
portion of the scientific research being conducted in U.S. waters. It 
is also unlikely that a cause-and-effect relationship would be able to 
be determined within a reasonable length of time to affect the work 
schedule. Even though it is a standard requirement in all IHAs to 
suspend activities if a taking occurred in a manner that was not 
authorized, mortality by this activity, caused either by a ship strike 
(because of the relatively low speed) or by seismic noise

[[Page 35796]]

(because of low SPL), is highly improbable. NMFS notes that the SPLs 
made by this activity are comparable to the vocalizations made by many 
species of marine mammals. If marine mammals vocalize at high SPL 
levels, it is realistic to believe that these species have also evolved 
mechanisms to protect themselves and conspecifics from high SPL 
vocalizations.
    Comment 10: Lifeforce has studied behavior and travel patterns of 
orcas over a 9-year period. This allows it to be able to locate and 
track orcas on a daily basis and to predict estimated times of their 
arrival in certain areas. Communication between Lifeforce and the 
research team would reduce many conflicts resulting from the merging 
and crossing of routes taken by the research team and the endangered 
orcas.
    Response: To the extent possible, NMFS recommends that the 
monitoring team for this activity coordinate with Lifeforce so that the 
acoustic harassment incidental to conducting a 2-day seismic program in 
U.S. waters is reduced to the lowest level practicable. However, this 
should not be interpreted to mean that the USGS can not conduct its 
activity without the participation of Lifeforce. Since the USGS will 
have an NMFS-approved observation team onboard the vessel, additional 
monitoring tasks are not needed, but would be useful.
    Comment 11: Many of the species which could be affected by this 
research are transboundary species making their homes in both the U.S. 
and Canadian waters. Lifeforce urges NMFS to advise both American and 
Canadian participants that they must follow all requirements to protect 
marine wildlife as stated in the MMPA and all requirements set forth in 
any permit.
    Response: The MMPA is effective in U.S. waters and, for U.S. 
citizens, on the global commons; it is not effective within the waters 
of another nation. As a result, NMFS is recommending that the USGS 
follow Canadian law while operating within that nation's waters. To the 
extent possible, NMFS recommends that the USGS follow the mitigation 
requirements of the IHA while within these waters, unless required by 
Canada to comply with other methods for protecting marine mammals.
    Comment 12: Lifeforce recommends that a new Environmental Impact 
Study should be considered because during the past 6 years there has 
been a 20-percent decrease in the southern orca community. The 
last EIS was conducted 5 years ago.
    Response: In conjunction with a seismic survey project in Puget 
Sound in 1998, NMFS completed an EA that addressed the impacts on the 
human environment from issuance of an authorization and the 
alternatives to that action. NMFS' analysis resulted in a Finding of No 
Significant Impact (FONSI). As a result of that finding, in accordance 
with Council on Environmental Quality regulations (40 CFR 1501.3) and 
NOAA Administrative Order 216-6 (i.e., NOAA's guidelines 
implementing the National Environmental Policy Act (NEPA)), an 
Environmental Impact Statement was not prepared. This seismic survey 
will operate in approximately the same geographic area as the 1998 
survey, and affect the same species of marine mammals. However, the 
airgun sources used in this action are significantly less intense the 
1998 array and only 2 percent of the size of the earlier acoustic 
array. Accordingly, this proposed action qualifies for a categorical 
exclusion under NEPA. A change in the status of a marine mammal stock 
does not necessarily require a new NEPA analysis; a new NEPA review 
would be required if either the impact of the action was different than 
assessed under the proposed action or alternatives in the EA, or if new 
knowledge became available that called into question the impact 
assessments made in the EA. Since neither situation is relevant here, a 
new NEPA analysis is unnecessary.

Description of Habitat and Marine Mammals Affected by the Activity

    A description of the affected habitat and its associated marine 
mammals can be found in the USGS application and in several documents 
issued previously for acoustic research in Washington State waters 
(NMFS, 1996, 1997).

Marine Mammals

    The species of marine mammals that are likely to be present in the 
region of the Straits of Georgia include the harbor porpoise (Phocoena 
phocoena), killer whale (Orcinus orca), Dall's porpoise (Phocoenoides 
dalli), harbor seal (Phoca vitulina) California sea lion (Zalophus 
californianus), elephant seal (Mirounga angustirostris) (Calambokidis 
and Baird, 1995) and Steller sea lion (Eumetopias jubatus) (NMFS data). 
Additional species that are rare or only occasionally seen in the area 
at the time of the survey include: Pacific white-sided dolphin 
(Lagenorhynchus obliquidens), minke whale (Balaenoptera acutorostrata) 
humpback whale (Megaptera novaengliae) and gray whale (Eschrichtius 
robustus). However, because of the short duration of this project in 
waters under the jurisdiction of the United States, it is very unlikely 
that these latter species would be subject to harassment as a result of 
conducting seismic surveys.
    General information on the marine mammal species can be found in 
the USGS application and the previously mentioned documents prepared 
under NEPA. Information on marine mammal species in this area can also 
be found in Caretta et al. (2002). In addition, a general synopsis of 
marine mammal presence and abundance in the Straits of Georgia area has 
been provided by NMFS' National Marine Mammal Laboratory for the 
determinations made here. That paper and the NEPA documents are 
available upon request (see ADDRESSES); Caretta et al. (2002) is 
available at the following URL: http://www.nmfs.noaa.gov/prot_res/readingrm/MMSARS/FinalPacSar2001.pdf. Please refer to these documents 
for information on marine mammal species.

Potential Effects of Seismic Surveys on Marine Mammals

Discussion

    Disturbance by seismic noise is the principal means of taking 
incidental to this activity. Vessel noise may provide a secondary 
source. Also, the physical presence of vessel(s) could also lead to 
some non-acoustic effects involving visual or other cues.
    The effects of underwater noise on marine mammals are highly 
variable, and can be categorized as follows (based on Richardson et 
al., 1995): (1) The noise may be too weak to be heard at the location 
of the animal (i.e. lower than the prevailing ambient noise level, the 
hearing threshold of the animal at relevant frequencies, or both); (2) 
the noise may be audible but not strong enough to elicit any overt 
behavioral response; (3) the noise may elicit behavioral reactions of 
variable conspicuousness and variable relevance to the well being of 
the animal; these can range from subtle effects on respiration or other 
behaviors (detectable only by statistical analysis) to active avoidance 
reactions; (4) any noise that is strong enough to be heard has the 
potential to reduce (mask) the ability of marine mammals to hear 
natural sounds at similar frequencies, including calls from 
conspecifics and/or echolocation sounds, and environmental sounds such 
as storms and surf noise; (5) upon repeated exposure, animals may 
exhibit diminishing responsiveness (habituation), or disturbance 
effects may persist (the latter is most likely with sounds that are 
highly variable in characteristics, unpredictable in occurrence, and 
associated with

[[Page 35797]]

situations that the animal perceives as a threat); and (6) very strong 
sounds have the potential to cause either a temporary or a permanent 
reduction in hearing sensitivity (i.e., temporary threshold shift (TTS) 
or permanent threshold shift (PTS), respectively). In addition, intense 
acoustic or explosive events may cause trauma to tissues associated 
with organs vital for hearing, sound production, respiration and other 
functions. This trauma may include minor to severe hemorrhage.
    Few data on the effects of non-explosive sounds on hearing 
thresholds of marine mammals have been obtained. However, in 
terrestrial mammals (and presumably in marine mammals), received sound 
levels must far exceed the animal's hearing threshold for there to be 
any TTS and must be even higher for there to be risk of PTS (Richardson 
et al., 1995).
    Depending upon ambient conditions and the sensitivity of the 
receptor, underwater sounds produced by large-scale open-water seismic 
operations may be detectable some substantial distance away from the 
activity. Any sound that is detectable is (at least in theory) capable 
of eliciting a disturbance reaction by a marine mammal or masking a 
signal of comparable frequency. Incidental harassment is presumed to 
occur when marine mammals in the vicinity of the seismic source (or 
vessel) show a significant behavioral response to the generated sounds 
or visual cues.
    High-intensity LF seismic pulses are known to cause some species of 
whales, including gray and bowhead whales, to behaviorally respond 
within a distance of several kilometers of the source (Richardson et 
al., 1995). Although some limited masking of low-frequency sounds is a 
possibility for those species of whales using low frequencies for 
communication, the intermittent nature of seismic source pulses limit 
the extent of masking. Bowhead whales, for example, are known to 
continue calling in the presence of seismic survey sounds, and their 
calls can be heard between seismic pulses (Richardson et al., 1986).
    When the received levels of noise exceed some behavioral reaction 
threshold, cetaceans will show disturbance reactions. The levels, 
frequencies, and types of noise that will elicit a response vary 
between and within species, individuals, locations and season. 
Behavioral changes may be subtle alterations in surface-dive-
respiration cycles. More conspicuous responses include changes in 
activity or aerial displays, movement away from the sound source, or 
complete avoidance of the area. The reaction threshold and degree of 
response are related to the activity of the animal at the time of the 
disturbance. Whales engaged in active behaviors such as feeding, 
socializing or mating are less likely than resting animals to show 
overt behavioral reactions, unless the disturbance is directly 
threatening.
    Neither hearing damage nor nonauditory trauma are expected to occur 
as a result of this project. While TTS is a theoretical possibility for 
marine mammals close to an acoustic source, if the SPL of the source is 
of sufficient intensity, planned monitoring and mitigation measures 
(described later in this document) are designed to detect marine 
mammals occurring near the airgun array and to avoid, to the greatest 
extent practicable, exposing them to sound pulses that have any 
possibility of causing TTS.
    Two factors determine the effect of the airgun array on marine 
mammals: (1) The intensity of the sound (mentioned previously in this 
document), and (2) the frequency range of the sound. The airgun sound 
spreads laterally in the water as the radius of the sound wave 
increases, resulting in a decrease in amplitude with distance of 
20Log(R) or greater (R= distance in meters). Given this estimate of 
decay, a 230 dB(P-P) sound pressure decays to 180 dB(P-P) at a distance 
of about 300 m (984.3 ft)(see Figure 4 in the USGS application) from 
the source.
    The 300-m (984.3-ft) distance, however, is clearly an 
overestimate for an estimation for a zone of potential injury (i.e., 
180 db) because (1) it is based on a P-P measurement and not the 
accepted RMS measurement and (2) the frequency range of the airgun lies 
primarily outside the hearing range of most marine mammals. Data on 
hearing thresholds for odontocetes and pinnipeds show that the most 
sensitive hearing is in the 1,000- to 100,000-Hz frequency 
range (see Figure 5 in the USGS application; Richardson et al., 1995; 
Kastack and Schusterman, 1995). The USGS airgun source rapidly 
decreases in strength above 200 Hz, resulting in the source strength 
above 400 Hz being less than 10 percent of the amplitude at lower 
frequencies.
    The USGS has estimated the SPL of its airgun source as a function 
of frequency. The P-P sound pressure is created by the sum of waves of 
all the frequencies emitted by the airguns, with each frequency 
contributing only a portion of the total sound. If the maximum P-P SPL 
is divided by the frequency spectrum of the airgun array, the amplitude 
of the individual frequency components can be estimated at several 
distances, as shown in Figure 5 of the USGS application. The results 
indicate that the noise from any specific frequency emitted from the 
airgun array lies below the TTS of marine mammals at all distances (see 
Fig. 5 in the application).
    The latter estimate of the strength of the individual frequency 
components is an underestimate, however, because it assumes that all 
the frequencies are exactly in phase to produce the sound pulse. In 
reality, the system is not perfectly efficient as implied in this 
calculation, and the individual frequency components are somewhat 
larger than shown in Figure 4 in the USGS application. If it is assumed 
that the USGS source is about 70 percent efficient, the individual 
frequency components would be about 1.43 times what the USGS estimates 
assuming perfect efficiency. By this calculation, the sound levels from 
the airgun lie below the temporary hearing shift of most marine mammals 
at any distance greater than 50 m (164 ft)(USGS, 2001).
    NMFS concurs with the USGS that the best estimate of the strength 
of the airgun source is the 209 dB(RMS) measure of sound pressure. 
Using this RMS measure, the "annoyance" or behavioral-
response threshold is reached at a distance of 300 m (984.3 ft) from 
the airguns based on a P-P measurement (Table 4 in the USGS 
application) and less than 50 m (164 ft) on an RMS measurement 
(subtracting 16 dB from each of the Y-axis SPL designations). This 
implies that animals 50 m (164 ft) from the USGS airguns may become 
annoyed (harassed), but TTS would potentially not occur unless the USGS 
airguns were within about 5-10 m (16.4-32.8 ft) of a 
mammal.
    In light of the above information and recent scientific information 
that indicates that nonauditory injury is unlikely at SPL levels below 
190 dB (Crum and Mayo, 1996); and frequencies below 300 Hz (Ketten, 
2001), nonauditory injury is also unlikely for marine mammals exposed 
to this acoustic source.

Mitigation

    Several mitigation measures to reduce the potential for marine 
mammal harassment will be implemented by USGS as part of their proposed 
activity. These include:
    (1) Scheduling the survey during May, when marine mammal abundance 
in the Straits of Georgia is low;
    (2) Keeping the vessel's speed between 6 and 8 knots to permit 
marine mammals that hear the ship and airgun noise to be able to move 
out of the area of the ship's track if they find the

[[Page 35798]]

approaching vessel and accompanying noise annoying;
    (3) Establishing a safety zone of 100 m (328 ft) around the seismic 
airguns; the USGS will shut down the airgun operation if any marine 
mammal enters the safety zone. The 100-m (328-ft) distance 
is double the 50-m (164-ft) estimate of the distance for 
harassment. This safety zone radius compares with a 100-m 
(328-ft) safety radius for marine mammals that was used 
successfully in the 1998 Puget Sound seismic experiment using much 
larger airguns (Fisher, 1997; Calambokidis and Osmek, 1998; Bain, 
1998). Given that the current USGS airgun source is only 2 percent of 
the size of the 1998 source as measured in chamber volume (120 inch\3\ 
versus 6730 inch\3\), NMFS concurs with the USGS that a 100-m 
(328-ft) safety radius is overly conservative to ensure that no 
marine mammals would be injured and that the potential even for marine 
mammal harassment is unlikely.
    (4) For all seals and sea lions, if the seismic vessel approaches a 
pinniped, a safety radius of 100 m (328 ft) will be maintained from the 
animal(s). However, if a pinniped (except Steller sea lions) approaches 
the towed airgun array during airgun transmissions, the USGS will not 
be required to shutdown the airguns, unless the animal(s) shows signs 
of distress. Therefore, if a pinniped (except Steller sea lions) 
approaches the USGS vessel, the IHA requires the USGS to monitor the 
interaction to ensure the animal does not show signs of distress. If 
the pinniped(s) show obvious distress, the USGS is to suspend airgun 
operations until the pinniped moves outside of the safety zone and to 
continue to conduct observations on effects on all pinnipeds after the 
airgun is again powered up. Experience indicates that pinnipeds will 
come from great distances to scrutinize seismic operations. Seals have 
been observed swimming within airgun bubbles, 10 m (33 ft) away from 
active arrays and, more recently, Canadian scientists, who were using a 
high-frequency seismic system that produced sound closer to pinniped 
hearing than will the USGS airgun array, describe how seals frequently 
approached close to the seismic source, presumably out of curiosity. 
Therefore, the above-mentioned mitigation plan has been proposed. In 
addition, the USGS will gather information on how often pinnipeds 
approach the airgun array on their own volition, and what effect the 
airguns appear to have on them.
    (5) To ensure no marine mammals are inadvertently harmed when data 
collection first begins or resumes after operations have ceased 
temporarily, the airguns will be turned on sequentially (if an array is 
used), so that peak power is achieved gradually to give marine mammals 
a chance to move away from the source.
    (6) Upon notification by a local stranding network that a marine 
mammal has been found dead within the waters of the Straits of Georgia 
or nearby U.S. waters when the array is operating within that body of 
water, NMFS will investigate the stranding to determine whether a 
reasonable chance exists that the USGS seismic survey project caused 
the animal's death. If NMFS determines, based upon a necropsy of the 
animal(s), that the death was likely due to the seismic source, the 
survey must cease U.S. operations until procedures are altered to 
eliminate the potential for future deaths.

Monitoring

    To monitor the 100-m (328-ft) safety zone when in U.S. 
waters, the USGS will have two trained observers, one on each side of 
the ship, specifically watching for marine mammals at all times that 
the airguns are operating. Members of the crew, specifically the ship's 
pilot, will also be instructed to immediately notify the observers if 
any marine mammals are sighted. However, in order for 24-hour 
operations to be undertaken, a sufficient number of biological 
observers must be available so that no single observer is on active 
watch for more than 3 consecutive hours.
    Observations will begin at least 15 minutes before airguns are 
turned on. The observers will be equipped with binoculars during the 
day and night-vision equipment during the night, both of which are 
believed adequate to monitor the 100-m (328-ft) safety zone 
while standing on the ship. The observers will order the airgun 
operations to cease if the vessel approaches within 100 m (328 ft) of a 
marine mammal during daylight hours and 50 m (164 ft) during nighttime 
operations.
    The objectives of the proposed monitoring program will be: to 
mitigate potential harassment of marine mammals, to document the number 
of animals of each species present in the vicinity of the sound 
transmissions, and to evaluate the reactions of marine mammals to these 
transmissions.

Reporting

    The USGS will provide an initial report to NMFS within 120 days of 
the completion of the Straits of Georgia marine seismic survey project. 
This report will provide dates and locations of seismic operations, 
details of marine mammal sightings, and estimates of the amount and 
nature of all takes by harassment. A final technical report will be 
provided by USGS within 1 year of completion of the project. The final 
technical report will contain a description of the methods, results, 
and interpretation of all monitoring tasks.

NEPA

    In conjunction with a seismic survey project in Puget Sound in 
1998, NMFS completed an EA that addressed the impacts on the human 
environment from issuance of an authorization and the alternatives to 
that action. NMFS' analysis resulted in a FONSI. This proposed seismic 
survey will operate in the same geographic area as the 1998 survey and 
as the seismic airgun sources used in this proposed action are 
significantly less intense. Accordingly, this proposed action qualifies 
for a categorical exclusion under NEPA. Therefore, a new EA will not be 
prepared. A copy of the 1997 EA is available upon request (see 
ADDRESSES).

Consultation

    Under section 7 of the ESA, NMFS has completed consultation on the 
issuance of this IHA. NMFS has concluded that this action is unlikely 
to adversely affect listed marine mammals because those species of 
whales that are listed under the ESA are not expected to be present in 
the inshore waters of the Straits of Georgia at the time of the year 
that the activity will take place. Steller sea lions, which are more 
common in British Columbia than the Straits of Georgia, are unlikely to 
be affected by low frequency seismic sources unless fairly close to the 
source. However, the acoustic source that will be used during this 
project is of low intensity and will not have a large zone of 
influence. Therefore, even though Steller sea lions may be fairly 
abundant in these waters in late spring, because of the small zone of 
influence for this source (less than 50 m (164 ft)), no Steller sea 
lions are expected to be taken during this short acoustic survey.

Conclusions

    NMFS has determined that the short-term impact of conducting a 
marine seismic survey in the Straits of Georgia will result, at worst, 
in a temporary modification in behavior by certain species of 
pinnipeds, and possibly some individual cetaceans. While behavioral 
modifications may be occur in certain species of marine mammals to 
avoid the resultant noise from airgun arrays, this behavioral change is 
expected to result in the harassment of only small

[[Page 35799]]

numbers of each of several species of marine mammals and would have no 
more than a negligible impact on the affected species or stocks of 
marine mammals.
    In addition, no take by injury and/or death is anticipated and 
takes by harassment will be at the lowest level practicable due to 
incorporation of the mitigation measures mentioned previously. No known 
rookeries, mating grounds, areas of concentrated feeding, or other 
areas of special significance for marine mammals occur within or near 
the planned area of operations during the season of operations.

Authorization

    As a result of these determinations, NMFS has issued an IHA to the 
USGS for the possible harassment of small numbers of several species of 
marine mammals incidental to collecting marine seismic data in Straits 
of Georgia region of Washington State, provided the above-mentioned 
mitigation, monitoring, and reporting requirements are incorporated.

    Dated: May 15, 2002.
David Cottingham,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 02-12718 Filed 5-20-02; 8:45 am]
BILLING CODE 3510-22-S