[Federal Register Volume 65, Number 5 (Friday, January 7, 2000)]
[Proposed Rules]
[Pages 1083-1088]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-405]



DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 216

[I.D. 121699A]


Small Takes of Marine Mammals Incidental to Specified Activities; 
San Francisco-Oakland Bay Bridge, Pile Installation Demonstration 
Project, San Francisco Bay, CA

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

ACTION: Notice of receipt of application and proposed authorization for 
a small take exemption; request for comments.

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SUMMARY: NMFS has received a request from the Federal Highway Agency 
(FHA) on behalf of the California Department of Transportation 
(CALTRANS) for the harassment of marine mammals incidental to a pile 
installation demonstration project (PIDP) at the San Francisco-Oakland 
Bay Bridge (SF-OBB), San Francisco Bay (the Bay), CA. Under the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to authorize CALTRANS to incidentally take, by harassment, 
small numbers of marine mammals in the above mentioned area for a 
period of 1 year.

DATES: Comments and information must be received no later than February 
7, 2000.

ADDRESSES: Comments on the application should be addressed to Donna 
Wieting, Chief, Marine Mammal Conservation Division,
    Office of Protected Resources, NMFS, 1315 East-West Highway, Silver 
Spring, MD 20910-3225. A copy of the application and a list of 
references used in this document may be obtained by writing to this 
address or by telephoning one of the contacts listed here.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, (301) 713-
2055 ext 128, or Tina Fahy, (562) 980-4023.

SUPPLEMENTARY INFORMATION:

Background

    Section 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of marine mammals by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified geographical region if certain findings are 
made and either regulations are issued or, if the taking is limited to 
harassment, a notice of a proposed authorization is provided to the 
public for review.
    Permission may be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s) and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses and 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 now 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.

[[Page 1084]]

Summary of Request

    On November 22, 1999, NMFS received an application from the FHA on 
behalf of CALTRANS, requesting authorization of an Incidental 
Harassment Authorization (IHA) for the possible harassment of small 
numbers of Pacific harbor seals (Phoca vitulina), and California sea 
lions (Zalophus californianus) incidental to conducting the PIDP at the 
SF-OBB.
    CALTRANS is currently in the planning stages of the SF-OBB East 
Span Seismic Safety Project (ESSSP). The ESSSP would include driving 
large piles into the Bay bottom. One of the hammers anticipated to be 
used for this task is larger than any pile-driving hammer previously 
used in the Bay. Due to the untested nature of these hammers and piles 
in the Bay, a pile installation demonstration is needed. The PIDP will 
provide CALTRANS with an opportunity to measure resulting sound 
pressure levels (SPL), both in air and under water, record impacts to 
marine mammals and experiment with measures to reduce potential harm to 
marine mammals prior to general use on SF-OBB piles.
    The PIDP site is located between Yerba Buena Island (YBI) and 
Oakland, in the area to the north of and between existing SF-OBB east 
span piers E6 and E9 (see figures 1 and 2 of the application). The PIDP 
site is approximately 2.0 km (1.24 mi) from northeast of the YBI harbor 
seal haul-out site, which is located immediately to the west of the 
lighthouse on the southernmost tip of the island.
    The anticipated pier foundations for the ESSSP will consist of 
large diameter (up to 110-m (361-ft) long), steel pipe piles that will 
be driven into the Bay floor. Current plans anticipate using 2.5-m 
(8.2-ft) diameter piles for a majority of the foundations and smaller 
1.5-m (4.9-ft) diameter pipe piles for others.
    Accurately predicting the characteristics of pile driving prior to 
field-testing is not possible because piles of this size and length 
have not previously been installed in Bay substrates and there is 
limited experience with driving piles of this size. Therefore, given 
the unprecedented nature of this work in the Bay, this PIDP will 
provide CALTRANS with an opportunity to gather important data regarding 
in-air and underwater sound pressure levels generated by the pile 
driving activities. In addition, it will also provide an opportunity to 
gather data from experimental measures to attenuate elevated SPLs, 
thereby reducing the potential for harm to marine mammals. Information 
obtained from this demonstration potentially may prove valuable for 
forecasting anticipated impacts of pile installation activities 
associated with a larger SF-OBB east span construction, which will 
require the installation of approximately 350 piles of variable 
diameter.

Project Description

    The PIDP includes driving three full-scale steel pipe piles (2.438 
m (8.0 ft) in diameter, 110 m (361 ft) long) at two locations (two at a 
primary site and one at an alternate site) near the existing SF-OBB 
east span alignment. Each pile consists of four segments of variable 
length and wall thickness that will each be driven, subsequently welded 
to another segment, and driven again until the full desired length and 
depth of the pile is achieved. Due to the nature of this work, the 
majority of the project time will be spent on surface support 
activities, such as picking up the pile segments, placing the segment 
in the correct spot and welding the segments together. Actual pile 
driving will only occur for a small fraction of the project's duration. 
Please refer to the CALTRANS application for a complete description of 
the pile driving order of work.
    Piles will be driven open-ended by hydraulic or steam hammers. 
These are large offshore hammers capable of driving large-diameter, 
thick-walled steel pipe piles. No other types of hammers (e.g. drop 
hammers, diesel hammers or vibratory hammers) will be used on this 
project. According to project specifications, two sizes of hammers are 
required. A ``smaller'' hammer having a maximum rated energy of not 
less than 500 kilojoules (kJ) but not more than 1,000 kJ will be used 
to drive initial segments of the piles. This hammer will be similar in 
size to the pile driving hammer that was used for activities associated 
with the retrofitting of the San Mateo-Hayward Bridge, also in the Bay. 
A larger hammer, having a maximum rated energy of not less than 1,700 
kJ will be employed to drive subsequent segments of each pile. No upper 
limit is placed on the maximum rated energy of the larger hammer, 
however there is little motivation to use a larger hammer than 
necessary unless there are no other hammers available at that time. 
Furthermore, the piles must be able to support the weight of the anvil, 
limiting the size of the hammer that can be used.
    The PIDP is expected to take place in late spring 2000. All 
necessary equipment for the PIDP will be brought to the project site on 
barges, tugboats and other marine vessels. Due to the high cost of the 
equipment being used for this project and the nature of pile 
installation, work will need to proceed 24 hours a day, 7 days a week 
for approximately 20 days barring unforeseen circumstances (i.e. broken 
equipment, adverse weather conditions). Actual impact hammering will 
only occur for a total of about 12 to 16 hours over the estimated 20 
days. Continuous impact hammering would likely occur for a maximum 
amount of 2-3 hours at a time. As 3 piles are being driven, this 
maximum would only be reached on 3 days out of the 20 days of the PIDP. 
The hammer is expected to hit the piles at an average rate of 30-45 
blows per minute.
    Due to the amount of time needed between driving consecutive pile 
segments, it is extremely unlikely that more than two segments will be 
driven in a 24-hour period. It is important to note that once the 
driving of a pile segment begins it cannot be halted until that segment 
has reached its desired depth. This is not only because of the expense 
of keeping the equipment idle but also due to the nature of the 
predominantly clay soil types underlying the Bay. As piles are driven, 
the soil gradually loses resistance. If driving is stopped, the soil 
has a chance to regain its strength, and resistance to the pile 
increases. This can make it more difficult or even impossible to 
continue driving the pile, particularly if the pile tip is in a highly 
resistant layer at that point. Consequently, once hammering resumes, it 
could potentially take a longer time at increased energy levels. This 
could amplify impacts to marine mammals, as they would endure 
potentially higher SPLs for longer periods of time. Pile segment 
heights and wall thickness have been specially designed for this 
project to take the location of highly resistant sediment layers into 
account, so that when work is stopped at the desired depths between 
segments, the pile tip is never resting in highly resistant sediment 
layers. In addition, stopping in the middle of pile driving a segment 
may interfere with the goal of understanding the characteristics of 
pile driving within this new setting. If pile driving is permitted to 
be regularly interrupted, meaningful data regarding how the piles 
behave may be difficult to obtain.

Description of the Marine Mammals Affected by the Activity

     General information on harbor seals, California sea lions, and 
other marine mammal species found in Central California waters can be 
found in Barlow et al. (1997, 1998). The marine mammals likely to be 
found in the SF-

[[Page 1085]]

OBB area are limited to the California sea lion and harbor seal.

California Sea Lions

    While California sea lions are known to have historically used the 
Bay, they are rarely observed hauled out in the Bay (Bauer, 1999). 
However, since at least 1987, sea lions have been observed occupying 
the docks near Pier 39 in San Francisco, about 5.7 km (3.5 mi) from the 
project site. The number of sea lions hauled out at Pier 39 ranged from 
63 to 737 in 1998 and from 5 to 906 in 1997 (Marine Mammal Center, 
Sausalito data). For both years, the lows occurred in June and the 
highs occurred in August. Most recently, 831 sea lions were observed on 
K dock at Pier 39 in October 1999. While they are present in large 
numbers, approximately 85 percent of the animals hauled out at this 
site are males, and no pupping has been observed at this site or any 
other site in the Bay (Lander pers. comm. to CALTRANS, 1999). At this 
time, no other sea lion haul-out sites have been identified in the Bay. 
About 90 percent of the U.S. stock breeds on the southern California 
Channel Islands, over 483 km (300 mi) from the PIDP site (Schoenherr, 
1995; Howorth and Abbott, 1999). Pier 39 has now become a regular haul-
out site for sea lions. The sea lions, most of whom are male, appear at 
the site after returning from the Channel Islands at the beginning of 
August (Bauer, 1999). Around late winter, sea lions begin to travel 
south to the breeding grounds, and numbers at the haul-out site 
decline. Lowest numbers of sea lions are usually observed from May 
through July. Numbers of sea lions at the haul-out site fluctuate quite 
a bit throughout the year and even from one week to the next. For 
example, in June of 1998, a maximum of 574 sea lions was observed on 
June 7th while a low count of 63 was observed on June 25th 
(Lander pers. comm. to CALTRANS, 1999).
    While little information is available on the foraging patterns of 
California sea lions in the Bay, individual sea lions have been 
observed feeding in the shipping channel to the south of YBI on a 
fairly regular basis (Grigg pers. comm. to CALTRANS, 1999). Foraging by 
sea lions that utilize the Pier 39 haul-out site primarily occurs in 
the Bay, where they feed on Pacific herring, northern anchovy and 
sardines, among other prey (Hanni, 1995).

Pacific Harbor Seals

    Pacific harbor seals are the only species of marine mammal that 
breed and bear young in the Bay (Howorth and Abbott, 1999). There are 
12 haul-out sites and rookeries in the Bay and of those, only eight are 
used by more than a few animals at a time. Only three sites in the Bay 
are regularly used by more than 40 harbor seals at any one time; these 
are Mowry Slough, located in the South Bay, YBI, and Castro Rocks, 
located in the Central Bay (Spencer, 1997). The three closest haul-out 
sites to the project location are at YBI, Angel Island, and Castro 
Rocks. The most recent aerial harbor seal count, conducted this year by 
D. Hanan of the California Department of Fish and Game, found 477 
individuals in the Bay (Green pers. comm. to CALTRANS, 1999). It is 
important to note that not all harbor seals were counted, as some may 
have been under water during the survey.
    Harbor seals are present in the Bay year-round and use it for 
foraging, resting and reproduction. Peak numbers of hauled-out harbor 
seals vary by haul-out site depending on the season. Results of a study 
of 39 radio-tagged harbor seals in the Bay found that most active 
diving occurred at night and a majority of the diving time was spent in 
seven feeding areas in the Bay. The two feeding areas located closest 
to the project site are just to the south of YBI and north of Treasure 
Island. This study also found that the seals dove for a mean time of 
0.50 minutes to 3.33 minutes. Mean surface intervals or the mean time 
the seals spent at the surface between dives ranged from 0.33 minutes 
to 1.04 minutes. Mean haul-out periods ranged from 80 minutes to 24 
hours (Harvey and Torok, 1994).
    Pupping season in the Bay begins in mid-March and continues until 
about mid-May. Pups nurse for only 4 weeks and mating begins after pups 
are weaned. In the Bay, mating occurs from April to July and molting 
season is from June until August (Schoenherr, 1995; Kopec and Harvey, 
1995).

Haul-Out Sites in the Vicinity of the PIDP

    YBI is located in the Central Bay, adjacent to man-made Treasure 
Island. The SF-OBB passes through a tunnel on YBI. An important harbor 
seal haul-out site is located on a rocky beach on the southwest side of 
YBI (Kopec and Harvey, 1995). Work for the PIDP will be performed 
approximately 2 km (1.24 mi) from this harbor seal haul-out site, 
facing the northwest side of the island.
    Although seals haul out year-round on YBI, it is not considered a 
pupping site for harbor seals as no births have been observed at the 
site. Occasionally, pups have been seen at an average of 1 pup per 
year, though more recently, 7 pups were observed at one time in May, 
1999 (San Francisco State University unpublished records, 1998-9). In a 
study of the haul-out site conducted between 1989 and 1992, males 
comprised 83.1 percent of the seals whose gender could be determined 
(Spencer, 1997). Peak numbers of harbor seals at this haul-out site 
have been observed from November to February. The maximum reported 
number of seals hauled out at one time is 344, counted in January 1992 
(Kopec and Harvey, 1995). More recently, the number of seals counted at 
YBI ranged from 0 to 296 for the period May 1998 to present. The 
maximum count of 296 was recorded on January 1999. Mean monthly counts 
for the same period range from 14.5 in September 1998 to 107.3 in June 
1999 (San Francisco State University, unpublished records 1998-9). The 
abundance of harbor seals at this site during the winter months likely 
coincides with the presence of spawning Pacific herring near the 
island. Re-sightings at the haul-out site indicate long-term usage of 
the site (Spencer, 1997).
    Angel Island is a small haul-out site located approximately 7.4 km 
(4.6 mi) from the project site. A maximum count of 15 seals was 
observed in the 1980s and most recently, six harbor seals were seen in 
1989. No pupping has been observed at the site.
    The next closest haul-out site is approximately 14 km (8.7 mi) away 
at Castro Rocks, near the Richmond end of the Richmond- San Rafael 
Bridge. The Castro Rocks haul-out site is a recognized pupping site. A 
maximum of 176 harbor seals were observed at Castro Rocks in October 
1999 (San Francisco State University unpublished records, 1998-9).

Potential Effects on Marine Mammals

    It is possible that California sea lions and harbor seals swimming 
in the project vicinity may be subject to elevated SPLs that could 
produce a temporary shift in the animal's hearing threshold. Pile 
driving noise and human activity around the PIDP could also potentially 
result in behavioral changes in nearby pinnipeds. California sea lions 
and harbor seals may temporarily cease normal activities, such as 
feeding, or pop their heads up above water in response to the noise. 
They may also be curious and choose to investigate the project site. 
However, existing evidence shows that most marine mammals tend to avoid 
loud noises (Richardson, pers. comm. to CALTRANS, 1999). It is likely 
then that harbor seals and sea lions in the water in the project 
vicinity may be temporarily displaced if they choose to avoid the area 
in response to the high SPLs. Due to the short-term nature of

[[Page 1086]]

the pile driving (approximately 12 to 16 hours over 20 days) and its 
distance from the YBI haul-out site, the PIDP is not expected to result 
in long-term behavioral impacts to Bay seals or sea lions.
    Based on in-air hammer noise measurements conducted elsewhere, the 
average received SPLs were 107 dB re 20 Pa measured 
at 10-20 meters (33-66 feet) from the hammer and between 70 dB and 44 
dB re 20 Pa at 2,400 meters (7,874 feet or 1.5 
miles) from the hammer. While a direct comparison is not possible due 
to different atmospheric and geographic conditions, it is anticipated 
that in-air noise levels at the YBI haul-out site, located 
approximately 2.0 km (1.24 miles) from the project site and physically 
shielded by the island, will attenuate to levels insufficient to cause 
injury to the seals and sea lions. It is also likely that harbor seals 
at this site will not be disturbed by the sound and leave the beach for 
the water, although they will most likely hear the pile driving noise.
    Consequently, while it is likely that hauled-out marine mammals 
will hear the pile driving activities, noise levels are not expected to 
adversely impact them. Impact hammering could potentially harass those 
harbor seals that are in the water closer to the project site, whether 
their heads are above or below the surface. Potential impacts could 
include a temporary elevation in hearing threshold and/or changes in 
behavior patterns. However, potential harassment would only occur 
during those times when piles are being hammered, estimated at 
approximately 12 to 16 hours over 20 days.
    It is difficult to estimate the number of California sea lions that 
could potentially be affected by the PIDP due to the lack of 
information on the number of sea lions in the Bay except for the Pier 
39 haul-out site. However, assuming the sea lion population at Pier 39 
starts to decline in the late winter as the sea lions migrate south to 
the rookeries, only a fraction of the animals would be left in the Bay 
at the time of the PIDP (late spring 2000). According to the Marine 
Mammal Center in Sausalito, the maximum number of sea lions observed at 
the Pier 39 haul-out site during the spring and summer seasons was 820 
in April 1999. The mean numbers of sea lions observed at Pier 39 during 
spring and summer seasons were 340 in 1998 and 453 in 1997 (Lander, 
personal communication to CALTRANS, 1999). Because the Pier 39 haul-out 
site is located 5.7 km (3.5 mi) away from the project site, only a 
fraction of those sea lions left in the Bay at the time of the project 
could potentially be in the project vicinity at any one time. Although 
California sea lions are known to forage in groups, available evidence 
suggests that they are not regularly seen in groups in the Bay waters 
near the PIDP site. In surveys conducted from May 1998 to the present, 
sea lions have been observed foraging in the shipping channel to the 
south of YBI. However, these sea lions are typically alone and do not 
seem to be associated with any other sea lions (Grigg, personal 
communication 1999). Given this anecdotal evidence, the number of sea 
lions expected to be present at the PIDP site during pile driving 
activities is expected to be low.
    Noise levels from the project are not expected to result in 
harassment of the sea lions hauled out at Pier 39 as SPLs would be 
expected to attenuate by the time they reach the haul-out site, 5.7 
kilometers (3.5 miles) from the project site. As most of the sea lions 
observed at Pier 39 are males, and the project will occur during the 
time when females and adult males are in waters off southern California 
for the breeding and pupping season, it is anticipated that most of the 
California sea lions impacted would be subadult males.
    Kopec and Harvey (1995) reported harbor seal counts for several 
haul-out sites in the Bay for the period 1989-1992.
    Peak numbers of harbor seals haul out at YBI in the winter months. 
The maximum recorded number of harbor seals observed at YBI is 344, 
recorded in January 1992. The PIDP is likely to occur in late spring of 
2000. According to Kopec and Harvey (1995), the maximum number of seals 
observed at the YBI haul-out site during the pupping season (March-
July) was 127 in 1992. More recently, for the same season, the Richmond 
Bridge Harbor Seal Survey reported a maximum count of 213 harbor seals 
observed in July 1998 (San Francisco State University, unpub. records 
1998-9). Kopec and Harvey reported mean harbor seal numbers of 35.7, 
41.1, 63.5 and 65.6 during the pupping seasons (March 15-May 31) of 
1989 to 1992, respectively (1995). The mean number of harbor seals 
observed during the pupping and molting seasons (March 15 to August 15) 
in 1998 and 1999 were 75.2 and 78.4, respectively (San Francisco State 
University, unpub. records 1998-9). Keeping in mind that these mean 
counts were taken for slightly different periods of time (March-July in 
1989-1992 and March-August in 1998-1999) and the number of surveys 
taken varies by count, the average of the mean counts is 60.

Mitigation

    Based upon a recommendation from NMFS, CALTRANS proposes to 
establish a 500-m (1640-ft) radius safety zone around the pile driving 
site. The safety zone is intended to include all areas where the 
underwater sound pressure levels are anticipated to equal or exceed 180 
dB re 1 Pa. Once pile driving begins, SPLs will be recorded at 
the 500-m contour. The safety zone radius will then be enlarged or 
reduced, depending on the actual recorded SPLs.
    Before pile driving of a pile segment begins, NMFS-approved 
observers on boats will survey the safety zone to ensure that no marine 
mammals are seen within the zone. If marine mammals are found within 
the safety zone, pile driving of the segment will be delayed until they 
move out of the area. If a marine mammal is seen above water and then 
dives below, the contractor will wait 15 minutes and if no marine 
mammals are observed in that time it will be assumed that the animal 
has moved beyond the safety zone. Harbor seals in the Bay are known to 
dive for a mean time of 0.50 minutes to 3.33 minutes (Harvey and Torok, 
1994). However, due to the limitations of monitoring from a boat, there 
can be no assurance that the safety zone will be devoid of all marine 
mammals.
    If marine mammals enter the safety zone after pile driving of a 
segment has commenced, hammering will continue unabated and marine 
mammal observers will monitor and record their numbers and behavior. 
For reasons mentioned previously, once the pile driving of a segment 
begins it cannot be stopped until that segment has reached its 
predetermined depth due to the nature of the sediments underlying the 
Bay.
    NMFS proposes to restrict actual pile driving to times when the 
safety zone can be monitored for the entire 15-minute monitoring period 
immediately prior to the start-up of pile driving. Also, in order to 
obtain information on the behavioral effects to harbor seals and 
California sea lions, NMFS proposes to require that a minimum of 50 
percent of the pile driving be scheduled during daylight hours. 
Daylight pile driving must include both hammer types.
    A 500-m (1640-ft) no-entry buffer zone will be established around 
the haul-out site on YBI to minimize the impact of project-related 
vessel traffic during the PIDP on marine mammals. This buffer zone will 
be established in coordination with the U.S. Coast Guard (USCG). The 
exclusion zone will be delineated with USCG-compliant temporary buoys 
to insure compliance.

[[Page 1087]]

CALTRANS will establish strict standards on vessel speed for all 
project-related crafts traveling in the Bay.
    The PIDP is expected to take place in late spring 2000. This timing 
would not coincide with the period of peak abundance at the YBI harbor 
seal haul-out site (November through February). Although harbor seal 
pupping and mating season will be ongoing in the Bay during the PIDP, 
YBI is not a known pupping site. Harbor seal molting season in the Bay 
begins in June. If the PIDP occurs during the harbor seal molting 
season, a greater proportion of harbor seals should be hauled out and, 
therefore, not subject to the potentially elevated in-water SPLs from 
pile driving.
    Finally, CALTRANS proposes to use this demonstration period to test 
the effectiveness of potential mitigation techniques. One potential 
mitigation measure is an underwater sound barrier based on the noise-
attenuating properties of air bubbles in water. At least two 
experimental techniques for creating underwater sound barriers will be 
tested by CALTRANS. Underwater SPLs will be recorded at various 
distances from pile driving activities in order to assess which 
measures, if any, prove practical and effective in reducing sound 
pressure levels.

Monitoring

    Monitoring of the safety zone will be conducted during all active 
pile driving. Monitoring of the safety zone will be conducted by a 
minimum of three qualified observers. The observers will begin 
monitoring at least 30 minutes prior to startup of the pile driving. 
Observers will likely conduct the monitoring from small boats, as 
observations from a higher vantage point (such as the SF-OBB) may not 
be practical.
    Observations will be made using binoculars during daylight hours. 
For operations at night, infrared or image intensifying equipment will 
be used. In addition to monitoring from boats, monitoring of the YBI 
haul-out will be conducted on land during all active pile driving. Data 
on all observations will be recorded and will include items such as 
species, numbers, time of observation, location, behavior, etc.
    Both underwater and airborne SPL measurements will be made.

Underwater Sound Monitoring

    Waterborne sound from the pile driving will be measured at 
approximately four locations. These locations will typically be in some 
combination of: (i) close to the pile driving activity, (ii) two mid-
point locations, and (iii) one distant location. Each measuring system 
will consist of a hydrophone with charge type conditioning amplifier 
connected to a sound level readout device and an instrumentation-grade 
digital audio tape (DAT) recorder. ``Real-time'' amplitude DAT 
measurements of underwater sound levels will be provided. The 
hydrophone will be deployed from a skiff to an appropriate depth at 
each location. A portable geostationary positioning system (GPS) unit 
will document the location coordinates of the skiff. It is anticipated 
that the sound level and frequency spectrum of the recorded noise 
signals will also be analyzed in a laboratory subsequent to the test.

Airborne Sound Monitoring

    Airborne sound from the pile driving will be measured at 
approximately four locations that are coincident with the underwater 
measurement locations (i.e., typically a combination of: (i) close to 
the pile driving activity, (ii) two mid-point locations, and (iii) one 
distant location). In addition, airborne sound will also be measured at 
Yerba Buena Island, as close as practicable to the haul-out site. Each 
measuring system will consist of a Type 1 Sound Level Meter (SLM) 
connected to an instrumentation-grade DAT recorder. ``Real-time'' 
amplitude measurements of airborne sound levels will be provided. The 
SLM will be equipped with a windscreen and tripod mounted on a skiff at 
approximately 1.2 meters above water level. As previously stated, a 
portable GPS unit will document the location coordinates of the skiff. 
It is anticipated that the sound level and frequency spectrum of the 
recorded noise signals will be analyzed in a laboratory subsequent to 
the test.

Reporting

    CALTRANS proposes to notify NMFS prior to the initiation of the 
PIDP, and coordination with NMFS will occur on a weekly basis, or more 
often, as necessary. NMFS will be informed of the initial sound 
pressure levels measurements taken at the 500-m (1640-ft) contour and 
the final safety-zone radius established. Monitoring reports will be 
faxed to NMFS on a daily basis. The daily report will include species 
and numbers of marine mammals observed, time and location of 
observation, behavior. In addition the report will include an estimate 
of the number of California sea lions and Pacific harbor seals that may 
have been harassed as a result of the pile driving activities.
    CALTRANS will provide NMFS with a final report detailing the 
monitoring protocol, a summary of the data recorded during monitoring, 
an estimate of the numbers of marine mammals that may have been 
harassed due to pile driving, and conclusions drawn from measurements 
with and without the attenuation measures.

Preliminary Conclusions

    Based on the previous discussion, NMFS has preliminarily determined 
that the PIDP may unintentionally cause the harassment of California 
sea lions and Pacific harbor seals. Although CALTRANS has requested an 
authorization for Level B harassment, as a result of a behavioral 
modification to avoid either pile driving noise or human activity, NMFS 
notes that, on occasion, monitoring the safety zone may not be 100 
percent effective. As a result, some harbor seals or California sea 
lions, while underwater in the vicinity of the PIDP, may incur levels 
above 180 dB re 1 Pa. At and above an SPL of this level, 
marine mammals may incur a temporary threshold shift (TTS) in hearing, 
lasting from a few minutes to a few hours. NMFS considers TTS to 
constitute Level A harassment (see Sec. 216.3 for a definition of Level 
A and Level B harassment).

[[Page 1088]]

    The PIDP is expected to have no more than an insignificant impact 
to marine mammals or their habitat. Harbor seals on YBI are commonly 
subjected to high levels of disturbance, primarily from watercraft, 
especially during the summer, when the numbers of small boats, jet 
skis, kayaks, etc. in the Bay increase. Abandonment of the haul-out 
site is not anticipated as sound levels from pile driving, both in 
water and in air, are expected to attenuate to sufficiently low levels 
by the time the SPLs reach the YBI haulout site. Although harbor seal 
pups have been observed at the YBI haul-out site, it is not a 
recognized pupping site and, therefore, no significant impacts on 
species recruitment are anticipated. Other haul-out sites for sea lions 
and harbor seals area are at a sufficient distance from the project 
site that they will not be affected.

Proposed Authorization

    NMFS proposes to issue an incidental harassment authorization to 
CALTRANS for the possible harassment of small numbers of harbor seals 
and California sea lions incidental to a PIDP at the SF-OBB, provided 
the previously mentioned mitigation, monitoring and reporting 
requirements are incorporated. NMFS has preliminarily determined that 
the proposed activities would result
in the harassment (as defined in the MMPA) of only small numbers of 
harbor seals and California sea lions and will have no more than a 
negligible impact on these marine mammal stocks.

Information Solicited

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

    Dated: December 28, 1999.
Ann D. Terbush,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 00-405 Filed 1-6-00; 8:45 am]
BILLING CODE 3510-22-F