[Federal Register Volume 65, Number 106 (Thursday, June 1, 2000)]
[Notices]
[Pages 35047-35053]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-13712]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[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 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) has been issued to the Federal Highway 
Administration (FHWA), on behalf of the California Department of 
Transportation (CALTRANS), to take small numbers of Pacific harbor 
seals and California sea lions, by harassment, incidental to a pile 
installation demonstration project (PIDP) at the San Francisco-Oakland 
Bay Bridge (SF-OBB), San Francisco Bay (the Bay), CA.

DATES: This authorization is effective from May 23, 2000, through May 
22, 2001.

ADDRESSES: A copy of the application may be obtained by writing to 
Donna Wieting, Chief, Marine Mammal Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225, or by telephoning one of the 
contacts listed here.

FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of 
Protected Resources, NMFS, (301) 713-2055, or Christina Fahy, Southwest 
Regional Office, NMFS, (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 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 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.

Summary of Request

    On November 22, 1999, NMFS received an application from the FHWA on 
behalf of CALTRANS, requesting an 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.

[[Page 35048]]

    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 SPLs 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 the 
larger ESSSP 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 
hammer, limiting the size of the hammer that can be used.
    The PIDP is expected to take place in late summer 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 when the fourth segment is being driven 
at an elevated energy level. As only 3 full-scale 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.

Comments and Responses

    A notice of receipt of the application and proposed authorization 
was published on January 7, 2000 (65 FR 1083), 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 CALTRANS. The MMC believes that NMFS' preliminary 
determination that the activity would have no more than a negligible 
impact on affected pinniped stocks is reasonable and sufficiently 
supported by the information and analyses provided in the Federal 
Register notice and in CALTRANS' request for a small take 
authorization. The MMC also believes that the monitoring program is 
adequate to verify that only small numbers of marine mammals are taken, 
that the taking is by harassment only, and that the impacts on the 
affected species and stocks are negligible. CALTRANS provided editorial 
comments that have resulted in minor modifications to this document and 
several broader comments which are addressed here.
    Comment 1: CALTRANS is concerned about the shape of the no-entry 
buffer zone around YBI. With the harbor seal haulout on the southwest 
side of the southern tip of the island, and a U.S. Coast Guard (USCG) 
facility on the southeast side, CALTRANS proposes modifying the no-
entry buffer zone to exempt the area of the USCG facility because of 
the need for the USCG's search-and-rescue to access the surrounding 
waters. This would minimize the potential for interference with the 
operation of the USCG facility while protecting hauled-out seals from 
potential harassment by project-related vessels.
    Response: NMFS notes that the revised YBI safety zone proposed by

[[Page 35049]]

CALTRANS is a 90-degree pie-shaped wedge with its southern limit 
extending southeasterly from the southern tip of YBI so that it 
encompasses an area within the seals' line of sight from the haul-out 
site, but not extending eastward around the southern tip of the island. 
NMFS believes however, that this proposal does not account for the 
harbor seal's line of sight to the southwest and west of the haulout. 
As a result, NMFS has established the western boundary of the YBI 
safety zone beginning at the first rock outcropping to the west of the 
seal haulout. However, it should be recognized that this mitigation 
measure does not supercede NMFS guidelines that require boats in 
California waters to remain at least 91 m (300 ft) from seals and sea 
lions that are on land or rocks. Therefore, in waters east and west of 
the CALTRANS' safety zone, NMFS' guideline provides additional 
protection to seals and sea lions that are ashore at YBI.
    Comment 2: CALTRANS has requested USCG authorization for the 
placement of buoys around the haul-out site.
    Response: NMFS understands that CALTRANS has two options: CALTRANS 
can either require contractors to stay out of the safety zone around 
the haul-out site, or it could buoy the area. However, if the area is 
buoyed, CALTRANS would have to go through the Private Aid to Navigation 
permitting process. Conditions of the permit would require notice to 
mariners because mariners may get confused if they see the buoys and do 
not know what they are for. Since the safety zone is primarily to 
reduce disturbance to marine mammals from the PIDP, and not for the 
exclusion of all boating activity, and because NMFS guidelines require 
boats in California waters must remain at least 91 m (300 ft) from 
seals and sea lions that are on land or rocks, NMFS does not consider 
buoying the area to be a required mitigation measure. CALTRANS can 
proceed on this issue as it chooses.
    Comment 3: CALTRANS foresees a potential problem with a mitigation 
measure that it proposed in its application. Essentially, CALTRANS 
notes that there is no provision for proceeding with work if a marine 
mammal enters the safety zone and remains visible, or if a seal or sea 
lion dives and reappears in the safety zone within the 15-minute time 
limit. Would the project be delayed indefinitely while the contractor 
waits for the marine mammal to leave the safety zone? If so, and the 
proposed authorization does not allow the contractor to drive a marine 
mammal from the safety zone or lure it away from the zone, the 
mitigation may not be practical. However, CALTRANS does not advocate 
that such activities be added to its authorization.
    Response: As noted by CALTRANS in its letter, harbor seals avoid 
human activity, California sea lions are unlikely to be in the vicinity 
of the project, and molting harbor seals will more likely be ashore 
than in the water at the time of the project. As a result, the scenario 
described by CALTRANS is not likely to occur. However, NMFS believes it 
would be inappropriate to include these types of intentional takings as 
a mitigation measure. If this develops into a problem, NMFS may take 
other action to resolve it.
    Comment 4: CALTRANS proposes a modification to the proposed 
authorization that would allow a pile-driving operation to begin after 
the first 15-minute waiting period whether or not a marine mammal is 
within the safety zone. CALTRANS believes that 15 minutes is sufficient 
time for a marine mammal to move outside the safety zone and yet allow 
the contractor to have some assurance of being able to proceed within a 
reasonable time frame. CALTRANS also believes that this change should 
not alter NMFS' preliminary conclusion that the PIDP would have the 
potential to harass only a small number of marine mammals.
    Response: In the proposed authorization, NMFS preliminarily 
concurred with CALTRANS that a safety zone should be established at a 
distance approximately 500 m (1,640 ft) from the PIDP. At this 
distance, CALTRANS estimated that the SPL from the pile driving would 
be 180 dB re 1 <greek-m>Pa-m<INF>RMS</INF>. In its application, 
CALTRANS used guidance provided by NMFS that impulse-generated SPLs 
greater than 180 dB had the potential to cause a temporary threshold 
shift (TTS) in marine mammal hearing levels and that, at some unknown 
level above 180 dB, marine mammals had the potential to incur a 
permanent shift (i.e., elevation) in hearing thresholds. While the 
previous NMFS statement remains true in general, present scientific 
consensus indicates that a safe level for impulse sounds for pinnipeds 
from incurring TTS is higher than the level indicated for cetaceans. As 
a result, scientists have preliminarily established an SPL of 190 dB re 
1 <greek-m>Pa-m<INF>RMS</INF> as a safe level for pinnipeds underwater. 
NMFS adopts this information as the best scientific information 
available and will allow CALTRANS to establish a safety zone at the 
distance from the PIDP where the SPL diminishes to 190 dB re 1 
<greek-m>Pa-m<INF>RMS</INF>. However, in order to implement this 
provision, CALTRANS must measure the distance acoustically for each 
hammer used and, until this distance is measured and an appropriate 
safety zone implemented, CALTRANS must retain a safety zone of 180 dB 
re 1 <greek-m>Pa-m<INF>RMS</INF>.
    NMFS believes the smaller safety zone for pinnipeds will allow 
CALTRANS to remain on schedule. If problems arise, NMFS will consider 
other appropriate actions, as necessary.
    Comment 5: CALTRANS has expressed concern with NMFS' proposal to 
require at least 50 percent of pile driving to be performed during 
daylight. CALTRANS believes that it will be nearly impossible to 
measure percentages of total pile driving time as construction 
proceeds. Instead, CALTRANS proposes that NMFS modify the previously 
mentioned monitoring measure and require pile driving ``episodes'' 
rather than total pile driving time. CALTRANS proposes to install the 
first 2 segments of each pile during daylight hours (for a total of 6 
pile driving episodes). The third and fourth segments, which are the 
most likely to refuse or freeze, would be driven when ready (taking 
into account the 15-minute delay for marine mammal presence) and this 
may or may not be during daylight hours. CALTRANS further proposes to 
conduct all restriking of the piles (5 episodes) during daylight hours. 
The larger hammer would be required for restriking, thereby meeting the 
proposed requirement that both hammer sizes be used during daylight. 
Furthermore, while the hammer would operate for a shorter time during 
restriking, it would be more likely to operate at the highest capacity. 
It is probable that the hardest driving and thus the loudest noise 
would be generated during re-striking.
    Response: As noted by CALTRANS in its letter, NMFS' intention for a 
requirement that 50 percent of strikings occur during the daytime was 
to obtain more meaningful data on seal and sea lion response to pile 
driving. As a result, NMFS concurs with the suggested modification.

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

[[Page 35050]]

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 spring, 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 7<SUP>th</SUP> 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 northeast 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 in 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 more 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, personal communication 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 
the pile driving (approximately 12 to 16

[[Page 35051]]

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 <greek-m>Pa measured at 10-20 
meters (33-66 feet) from the hammer and between 70 dB and 44 dB re 20 
<greek-m>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 spring 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 summer 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 summer 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, unpublished 
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, unpublished 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 previous discussion in this document, CALTRANS will 
establish a 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 190 dB re 1 
<greek-m>Pa<INF>RMS</INF>. Once pile driving begins, SPLs will be 
recorded to determine where this radius should be established. It is 
anticipated that safety zone radii will differ between the larger and 
smaller hammers.
    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 the presence of seals or sea lions within the safety zone 
seriously compromises CALTRANS' activity, CALTRANS will contact the 
Regional Administrator, NMFS, for appropriate resolution.
    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.
    Pile driving will be restricted to times when the safety zone can 
be monitored for 15 minutes 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 will require that, to 
the maximum extent practicable, a minimum of 50 percent of the 17 pile 
driving episodes be scheduled during daylight hours. Daylight pile 
driving must include both hammer types. In order to meet this 
mitigation measure, CALTRANS will drive the first two segments of each 
pile in daylight; the third and fourth segment of each pile will be 
driven when ready; and all

[[Page 35052]]

restriking of the piles will be performed in daylight.
    A 500-m (1640-ft), pie-shaped wedge 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 USCG. The 
exclusion zone will either be delineated with USCG-compliant temporary 
buoys to insure compliance, or all employees and contractors associated 
with the PIDP will be informed of the no-entry zone. In addition, 
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 summer 2000. This timing 
would not coincide with the period of peak abundance at the YBI harbor 
seal haul-out site (November through February). 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 (CALTRANS states that they will 
employ three observers in daytime and 6 observers during darkness 
(January 31, 2000, letter to NMFS)). 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: (1) close to the pile driving activity, (2) two mid-
point locations, and (3) 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: (1) close to 
the pile driving activity, (2) two mid-point locations, and (3) one 
distant location). In addition, airborne sound will also be measured at 
YBI, 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 will 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 SPL measurements taken 
to estimate the 190 dB re 1 <greek-m>Pa<INF>RMS</INF> contour and the 
final safety-zone radii 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, 
and 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.

Conclusions

    Based on the previous discussion, NMFS has 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 190 dB 
re 1 <greek-m>Pa<INF>RMS</INF>. 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. However, no take by death is 
anticipated, and harassment takes will be at the lowest level 
practicable due to incorporation of the mitigation measures mentioned 
above.
    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

[[Page 35053]]

distance from the project site that they will not be affected.
    Since NMFS is assured that the taking will not result in more than 
the incidental harassment (as defined by the MMPA) of small numbers of 
Pacific harbor seals and California sea lions, and would result in the 
least practicable impact on these stocks, NMFS has determined that the 
requirements of section 101(a)(5)(D) have been met and the 
authorization can be issued.

Authorization

    For the previously stated reasons, NMFS has issued an IHA for a 1-
year period, for the harassment of harbor seals and California sea 
lions incidental to a PIDP at the SF-OBB, San Francisco Bay, 
California, provided the above mentioned mitigation, monitoring and 
reporting requirements mentioned earlier are incorporated.

    Dated: May 23, 2000.
Art Jeffers,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 00-13712 Filed 5-31-00; 8:45 am]
BILLING CODE 3510-22-F