[Federal Register Volume 62, Number 170 (Wednesday, September 3, 1997)]
[Notices]
[Pages 46480-46483]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23251]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[I.D. 080897A]
Small Takes of Marine Mammals Incidental to Specified Activities;
Seismic Retrofit of the Richmond-San Rafael Bridge, 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 California Department of
Transportation (CALTRANS) for an authorization to take small numbers of
Pacific harbor seals and possibly California sea lions by harassment
incidental to seismic retrofit construction of the Richmond-San Rafael
Bridge, San Francisco Bay, CA (the Bridge). 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 1-year period
beginning in December 1997.
DATES: Comments and information must be received no later than October
3, 1997.
ADDRESSES: Comments on the application should be addressed to Michael
Payne, Chief, Marine Mammal Division, Office of Protected Resources,
NMFS, 1315 East-West Highway, Silver Spring, MD 20910-3225. A copy of
the application, a draft Environmental Assessment (EA) and a list of
references cited in this document may be obtained by writing to this
address or by telephoning one of the contacts listed below.
FOR FURTHER INFORMATION CONTACT: Kenneth R. Hollingshead, Office of
Protected Resources, NMFS, (301) 713-2055, or Irma Lagomarsino,
Southwest Regional Office, NMFS, (310) 980-4016.
SUPPLEMENTARY INFORMATION:
Background
Section 101(a)(5) (A) and (D) of the MMPA (16 U.S.C. 1361 et seq.)
directs 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
[[Page 46481]]
are made and either regulations are issued or, if the taking is limited
to harassment, 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), will not have an
unmitigable adverse impact on the availability of the species or
stock(s) for subsistence uses, and the permissible methods of taking
and requirements pertaining to the monitoring and reporting of such
taking 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.''
New section 101(a)(5)(D) of the Marine Mammal Protection Act
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.
New 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 July 7, 1997, NMFS received an application from CALTRANS,
requesting an authorization for the possible harassment of small
numbers of Pacific harbor seals (Phoca vitulina) and possibly some
California sea lions (Zalophus californianus) incidental to seismic
retrofit construction of the Bridge.
The Bridge will be seismically retrofitted to withstand a future
severe earthquake. Construction is scheduled to begin in December 1997,
and extend through December 2001. A detailed description of the work
planned is contained in CALTRANS (1996).1
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\1\ California Department of Transportation. 1996. Final Natural
Environmental Study/Biological Assessment for the Richmond-San
Rafael Bridge Seismic Retrofit Project. CALTRANS District 4.
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Among other things, seismic retrofit work will include: Excavation
around pier bases, hydro-jet cleaning, installation of steel casings
around the piers with a crane, installation of micro-piles and
installation of precast concrete jackets. Foundation construction will
require approximately 2 months per pier, with construction occurring on
more than one pier at a time. In addition to pier retrofit,
superstructure construction and tower retrofit work will also be
carried out. The construction duration for the seismic retrofit of
foundation and towers on Piers 52 through 57 will be approximately 7 to
8 months. Because of work restrictions and mitigation measures, the
seismic retrofit construction in this area will be completed within one
or two seasons.
As the seismic retrofit construction between Piers 52 and 57 may
potentially result in disturbance of pinnipeds at Castro Rocks, an MMPA
authorization is warranted.
Description of Habitat and Marine Mammals Affected by the Activity
A description of the San Francisco Bay ecosystem and its associated
marine mammals can be found in the CALTRANS application (CALTRANS 1997)
and CALTRANS (1996).
Castro Rocks are a small chain of rocky islands located next to the
Bridge and approximately 1,500 ft (460 m) north of the Chevron Long
Wharf. They extend in a south-westerly direction for approximately 800
ft (240 m) from Pier 55. The rocks start at about 55 ft (17 m) from
Pier 55 and end at approximately 250 ft (76 m) from Pier 53. The chain
of rocks is exposed during low tides and inundated during high tide.
Marine Mammals
General information on harbor seals and other marine mammal species
found in Central California waters can be found in Barlow et al.
(1995). The marine mammals likely to be found in the Bridge area are
limited to the California sea lion and harbor seal.
The California sea lion primarily uses the Central San Francisco
Bay area to feed. California sea lions are periodically observed at
Castro Rocks. No pupping or regular haulouts occur in the project area.
The harbor seal is the only marine mammal species found in the
Bridge area in significant numbers and, therefore, is described in
detail below.
Harbor Seals
The California stock of the Pacific harbor seal had an estimated
population size in 1994 of 34,554 (Barlow et al. 1995). Harbor seal
counts have continued to increase by 4.1 percent annually from 1983 and
1994, except during El Nino events of 1983 and 1995 (Barlow et al.
1995). During the same period however, harbor seal numbers within San
Francisco Bay remained stable; their 1994 estimated number being
approximately 350 (CALTRANS 1997).
The harbor seal is a non-migratory pinniped found in estuaries and
marine embayments and typically rests ashore (hauls out) on tidal-
inundated habitats such as mudflats, marshes, and near-shore rocky
outcroppings (Kopec and Harvey 1995; Zeiner et al. 1990). Haul-out
locations are used as resting sites and are important to the health of
harbor seals. Harbor seals feed opportunistically in shallow water on a
variety of fish, crustaceans, and a few cephalopods (Zeiner et al.
1990). Harbor seals often use isolated, undisturbed, sites for pupping
and molting. The numbers of harbor seals on haul-out sites fluctuates
throughout the year, but peaks generally occur during pupping and
molting at some sites, such as Castro Rocks. Typically, in San
Francisco Bay, pupping occurs from March to May, and molting occurs in
June (Kopec and Harvey 1995). Females usually give birth on land, often
at low tide, and the newborn pups are able to swim immediately after
birth (Zeiner et al. 1990).
In the San Francisco Bay area, harbor seals are known to haul out
at the Corte Madera ecological reserve in Marin County; at Castro Rocks
on the southeast end of the Richmond-San Rafael Bridge in the North
Bay; at Yerba Buena Island in Central San Francisco Bay; at several
locations along the western shoreline of the Dumbarton Bridge, on the
east side of the Bay (Newark and Mowry Soughs); and at the adjacent
coastal areas (such as Point Reyes, Bolinas Lagoon, and Pillar Point
(Kopec and Harvey 1995). In addition, several smaller or abandoned
haul-out sites occur in San Francisco Bay (Kopec and Harvey 1995).
The numbers of harbor seals at Castro Rocks varies year-round. The
most current independent surveys of harbor seals at Castro Rocks were
conducted from 1989 to 1992 by Kopec and Harvey (1995). Mean yearly
numbers of adults per count ranged from 76 to 113 during the pupping
season, and ranged from 48 to 67 during the non-pupping seasons.
[[Page 46482]]
Maximum numbers of harbor seal pups were between 13 and 26 for that
four-year period (Kopec and Harvey 1995). During biological surveys at
the Richmond-San Rafael Bridge, CALTRANS personnel counted 101 harbor
seals on June 16, 1994, all seals were adults. On June 25, 1996, census
data was again collected identifying 86 adults and 6 pups.
Harbor seals do not haul out at Castro Rocks at the highest tides.
Harbor seals first come ashore when tide levels drop below 3 ft (1 m)
on the eastern half of the easternmost island, closest to Pier 55. As
the tide drops further, seals haul out on every island in the chain.
Harbor seals haul out onto dry land for various biological reasons,
including sleep (Krieber and Barrette 1984), predator avoidance and
thermoregulation (Barnett 1992). As harbor seals spend most of the
evening and nighttime hours in the ocean (Bowles and Stewart 1980),
hauled-out seals spend much of their daytime hours in apparent sleep
(Krieber and Barrette 1984, Terhune 1985). In addition to sleep, seals
need to leave the ocean to avoid aquatic predators and excessive heat
loss to the sea water (Barnett 1992).
However, the advantages of hauling out are counterbalanced by
dangers of the terrestrial environment including predators. In general,
because of these opposing biological forces, haulout groups are
temporary, unstable aggregations (Sullivan 1982). The size of the
haulout group is thought to be an anti-predator strategy (da Silva and
Terhune 1988). By increasing their numbers at a haulout site, harbor
seals optimize the opportunities for sleep by minimizing the
requirement for individual vigilance against predators (Krieber and
Barrette 1984). This relationship between seals and their predators is
thought to have represented a strong selection pressure for startle
behavior patterns (da Silva and Terhune 1988). As a result, harbor
seals, which have been subjected to extensive predation or hunting,
rush into the water at the slightest alarm.
Startle response in harbor seals can vary from a temporary state of
agitation by a few individuals to the complete abandonment of the beach
area by the entire colony. Normally, when harbor seals are frightened
by noise, or the approach of a boat, plane, human, or other potential
predator, they will move rapidly to the relative safety of the water.
Depending upon the severity of the disturbance, seals may return to the
original haul out site immediately, stay in the water for some length
of time before hauling out, or haulout in a different area. When
disturbances occur late in the day, harbor seals may not haul out again
until the next day.
Disturbances have the potential to cause a more serious effect when
herds are pupping or nursing, when aggregations are dense, and during
the molting season. However, evidence to date has not indicated that
anthropogenic disturbances have resulted in increased mortality to
harbor seals. Bowles and Stewart (1980) for example, found that harbor
seals tendency to flee, and the length of time before returning to the
beach, decreased during the pupping season. They also found that
maternal-pup separations in crowded colonies are considered frequent,
natural occurrences that can result from several causes, including
normal female-female or male-female interactions. Both factors
apparently giving some protection to young seals from the startle
response of the herd.
Potential Effects on Marine Mammals
The impact to the harbor seals and California sea lions would be
disturbance by the presence of workers, construction noise, and
construction vessel traffic. Disturbance from these activities is
expected to have a short-term negligible impact to a small number of
harbor seals and sea lions. These disturbances will be reduced by
implementation of the proposed work restrictions and mitigation
measures (see below).
During the work period, harbor seal and on rare occasions,
California sea lion incidental harassment is expected to occur on a
daily basis upon initiation of the retrofit work. When harbor seals no
longer perceive construction noise and activity as being threatening,
they are likely to resume their regular hauling out behavior. The
number of seals disturbed will vary daily depending upon tidal
elevations. It is expected that disturbance to harbor seals during peak
periods of abundance will not occur since construction activities will
not take place within the restricted work area during the peak period
(see Mitigation below).
It is not known whether California sea lions will react to
construction noise and move away from the rocks during construction
activities. Sea lions are generally thought to be more tolerant of
human activities than harbor seals and are likely therefore to be less
impacted.
Potential Effect on Habitat
Short-term impacts of the activities are expected to result in a
temporary reduction in utilization of the Castro Rocks haul out site
while work is in progress or until seals acclimate to the disturbance.
This will not likely result in any permanent reduction in the number of
seals at Castro Rocks. The abandonment of Castro Rocks as a harbor seal
haul out and rookery is not anticipated since existing traffic noise
from the Bridge, commercial activities at the Chevron Long Wharf used
for off-loading crude oil, and considerable recreational boating and
commercial shipping currently occur within the area. In addition,
mitigation measures and proposed work restrictions are designed to
preclude abandonment.
Therefore, as described in detail in CALTRANS (1996), other than
the potential short-term abandonment by harbor seals, of part or all of
Castro Rocks during retrofit construction, no impact on the habitat or
food sources of marine mammals are likely from this construction
project.
Mitigation
Several mitigation measures to reduce the potential for marine
mammal harassment will be implemented by CALTRANS as part of their
proposed activity. General restrictions include: No piles installed
between 7 p.m. and 7 a.m., imposition of a construction noise limit of
86 dBA at 50 ft (15 m) between 7 p.m. and 7 a.m., and a limitation on
construction noise levels for 24 hrs/day in the vicinity of Castro
Rocks during the pupping/molting restriction period.
Marine mammal mitigation measures include: (1) A February 1 through
June 30 restriction on work in the water south of the Bridge center
line and on piers and pilings from Piers 52 through 57; and (2) no
watercraft will be deployed during the year within the exclusion zone
located between Piers 52 and 57 on the south side of the Bridge, except
for when construction equipment is required for seismic retrofitting of
piers 52 through 57. This exclusion area will be restricted as a
controlled access area on plans and will be marked off with buoys
located 200 ft (60 m) from the rocks.
To further minimize potential harassment, NMFS proposes to require
CALTRANS to the following: (1) Minimize vessel traffic in the exclusion
zone when conducting construction activities between piers 52 and 57;
(2) construction noise levels on the superstructure will be limited to
86 dB re 20 Pa-m for 24 hours/day in the vicinity of Castro
Rocks during the pupping/molting restriction period; and (3) no
retrofit construction work will occur on the towers associated with
piers 52 through 57 between February 1 and June 30.
[[Page 46483]]
Monitoring
During the time that seismic retrofit construction activities occur
on Piers 52 through 57, harbor seal monitoring at Castro Rocks will be
made for an 8-hour period once a week. Sound levels will be recorded on
those days that seals are being monitored. Monitoring will be conducted
by a minimum of one trained biologist approved by NMFS.
Monitoring of harbor seals at Castro Rocks will continue on a
quarterly basis for one year after the retrofit construction is
completed.
Reporting
CALTRANS will provide weekly reports to NMFS and a final report
will be provided within 3 months of completion of construction work on
Piers 52 through 57. These reports will provide dates, time, tidal
height, maximum number of harbor seals ashore, number of adults and
sub-adults, number of females/males, number of redcoats, and any
observed disturbances. A description of retrofit activities at the time
of observation and any sound pressure levels measurements made at the
haulout.
CALTRANS will provide NMFS with a follow-up report on the post-
construction monitoring activities within 18 months of project
completion in order to evaluate whether haul-out patterns are similar
to the pre-retrofit haul-out patterns at Castro Rocks.
National Environmental Policy Act
In conjunction with this notice, NMFS has released a draft EA that
addresses the impacts on the human environment from issuance of the
authorization and the alternatives to the proposed action. A copy of
the draft EA is available upon request (see ADDRESSES).
Conclusions
NMFS has preliminarily determined that the short-term impact of a
seismic retrofit construction of the Bridge will result, at worst, in a
temporary modification in behavior by harbor seals and possibly some
California sea lions. While behavioral modifications, including
temporarily vacating the haul-out, may be made by these species to
avoid the resultant noise, this action is expected to have a negligible
impact on the animals. In addition, no take by injury and/or death is
anticipated and takes will be at the lowest level practicable due to
incorporation of the mitigation measures mentioned above.
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 seismic retrofit construction of
the Bridge, provided the above mentioned mitigation, monitoring and
reporting requirements are incorporated. NMFS has preliminarily
determined that the proposed activities would result in the harassment
of only small numbers of harbor seals and possibly 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: August 26, 1997.
Hilda Diaz-Soltero,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 97-23251 Filed 9-2-97; 8:45 am]
BILLING CODE 3510-22-P
