Marine mammals: Incidental taking; authorization letters, etc.— San Francisco-Oakland Bay Bridge, CA; construction of east span; California sea lions, etc.,

[Federal Register: May 8, 2006 (Volume 71, Number 88)]

[Notices]

[Page 26750-26754]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr08my06-33]

[[Page 26750]]

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[I.D. 041706A]

Taking of Marine Mammals Incidental to Specified Activities; Construction of the East Span of the San Francisco-Oakland Bay Bridge

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

ACTION: Notice of issuance of an incidental harassment authorization.

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 California Department of Transportation (CALTRANS) to take small numbers of California sea lions, Pacific harbor seals, harbor porpoises, and gray whales, by harassment, incidental to construction of a replacement bridge for the East Span of the San Francisco-Oakland Bay Bridge (SF- OBB) in California.

DATES: This authorization is effective from April 30, 2006, until April 29, 2007.

ADDRESSES: A copy of the application, IHA, and/or a list of references used in this document may be obtained by writing to Steve Leathery, Chief, Permits, Conservation and Education Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225.

FOR FURTHER INFORMATION CONTACT: Shane Guan, NMFS, (301) 713-2289, ext 137, or Monica DeAngelis, NMFS, (562) 980-3232.

SUPPLEMENTARY INFORMATION:

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking by Level B harassment of small numbers of marine mammals of a species or population stock 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, notice of a proposed authorization is provided to the public for review.

Permission may be granted if NMFS finds that the taking will have no more than 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 that 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.

Section 101(a)(5)(D) of the MMPA established an expedited process by which citizens of the United States can apply for an authorization to incidentally take small numbers of marine mammals by harassment. Except with respect to certain activities not pertinent here, the MMPA defines ``harassment'' as:

any act of pursuit, torment, or annoyance which (i) has the potential to injure a marine mammal or marine mammal stock in the wild [Level A harassment]; or (ii) has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering

[Level B harassment] .

Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of an application followed by a 30-day public notice and comment period on any proposed authorizations for the incidental harassment of 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 October 17, 2005, CALTRANS sumbitted a request to NOAA requesting renewal of an IHA for the possible harassment of small numbers of California sea lions (Zalophus californianus), Pacific harbor seals (Phoca vitulina richardsi), harbor porpoises (Phocoena phocoena), and gray whales (Eschrichtius robustus) incidental to the construction of a replacement bridge for the East Span of the SF-OBB, in San Francisco Bay (SFB or the Bay), California. An IHA was issued to CALTRANS for this activity on January 3, 2005 and expired on January 3, 2006 (70 FR 2123, January 12, 2005). Background information on the issuance of this IHA was published in the Federal Register on January 26, 2006 (71 FR 4352). A detailed description of the SF-OBB project was provided in the Federal Register on November 14, 2003 (68 FR 64595), and is not repeated here.

Comments and Responses

A notice of receipt and request for 30-day public comment on the application and proposed authorization was published on January 26, 2006 (71 FR 4352). During the 30-day public comment period, comments were received from the Marine Mammal Commission (the Commission).

Comment 1: The Commission believes NMFS' preliminary determinations are reasonable, provided that the visual monitoring of the safety zone to be conducted prior to and during pile driving operations is adequate to detect all marine mammals within the safety zone. According to CALTRANS, pile driving would occur from 7 a.m. to 7 p.m., visual monitoring in the late afternoon and early evening would be compromised during the winter months.

Response: The Marine Mammal Monitoring Plan developed by CALTRANS in May 2002 notes that marine mammal observers will have night-time infrared (IR) scopes or other tools to conduct monitoring during low light conditions. CALTRANS has indicated that when using the IR scopes the marine mammal safety zone and marine mammals are visible. Please also refer to Federal Register notice published on November 14, 2003 (68 FR 64595) for additional information. NMFS will require the use of IR scopes in the IHA.

Comment 2: The Commission continues to believe that, in situations where a temporary threshold shift (TTS) may lead to biologically significant behavioral effects (e.g., an increased risk of natural predation or ship strikes), it should be considered as having the potential for injury (i.e., Level A Harassment).

Response: CALTRANS will implement a series of mitigation measures including visual monitoring prior to and during construction, installation of a bubble curtain for in-water pile driving, establishment of safety/buffer zones, and implementing ``soft star'' hammer strikes. Based on CALTRANS' June 2004 and January 2005 annual monitoring reports, the East Span Project is resulting in only small numbers of pinnipeds being harassed (through October 2005, the biological observers indicated that only one startle behavior of a sea lion was observed as a result of construction). Therefore, NMFS believes that it is not likely that a TTS would occur. In addition, NMFS has addressed the issue

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of impact assessment in several previous small take authorizations, and without new scientific documentation on this issue, a detailed response is not warranted here. For reviewers interested in this discussion, refer to the incidental take authorizations for the USS WINSTON S. CHURCHILL shock trial (66 FR 22450, May 4, 2001) and Eglin Air Force Base's Precision Strike Weapon (70 FR 48675, August 19, 2005).

Comment 3: An across-the-board redefinition of TTS from Level A harassment to Level B harassment raises questions both in terms of the activities that involve the potential for repeated TTS harassment and of general cumulative effects. The Commission recommends that NMFS revise its assessment of TTS accordingly.

Response: As NMFS has stated in a previous Federal Register notice (68 FR 64595, November 14, 2003) that the reclassification of TTS is irrelevant for this IHA, since mitigation and monitoring requirements under the IHA should prevent TTS. While there have been debates among scientists regarding whether a permanent shift in hearing threshold (PTS) can occur with repeated exposures of TTS, at least one study showed that long-term (4 - 7 years) noise exposure on three experimental pinniped species had caused no change on their underwater hearing thresholds at frequencies of 0.2 - 6.4 kHz (Southall et al., 2005).

Description of the Marine Mammals Potentially Affected by the Activity

General information on the marine mammal species found in California waters can be found in Caretta et al. (2004), which is available at the following URL: http://www.nmfs.noaa.gov/pr/PR2/Stock_Assessment_Program/sars.html. Refer to that document for information

on these species.

The marine mammals most likely to be found in the SF-OBB area are the California sea lion, Pacific harbor seal, and harbor porpoise. From December through May gray whales may also be present in the SF-OBB area. Information on these 4 species was provided in the November 14, 2003 (68 FR 64595) and January 26, 2006 (71 FR 4352) Federal Register notices and is not repeated here.

Potential Effects on Marine Mammals and Their Habitat

CALTRANS and NMFS have determined that open-water pile driving, as outlined in the project description, has the potential to result in a Level B harassment (e.g., disruption of behavioral patterns) of California sea lions, Pacific harbor seals, harbor porpoises, and gray whales that may be swimming, foraging, or resting in the project vicinity while pile driving is being conducted. Pile driving could potentially harass those few pinnipeds that are in the water close to the project site, whether their heads are above or below the surface.

Based on airborne noise levels measured and on-site monitoring conducted during 2004 under the previous IHA, noise levels from the East Span project did not result in the harassment of harbor seals hauled out on Yerba Buena Island (YBI). Also, noise levels from the East Span project are not expected to result in harassment of the sea lions hauled out at Pier 39 as airborne and waterborne sound pressure levels (SPLs) would attenuate to below harassment levels by the time they reach that haul-out site, 5.7 kilometers (3.5 miles) from the project site.

For reasons provided in greater detail in NMFS' November 14, 2003 (68 FR 64595) Federal Register notice and in CALTRANS' June 2004 and January 2005 annual monitoring reports, the East Span Project is resulting in only small numbers of pinnipeds being taken by Level B harassment (through October 2005, the biological observers indicated that only one startle behavior of a sea lion was observed as a result of East Span construction) and, therefore, is not expected to result in more than a negligible impact on marine mammal species or stocks and will not have a significant impact on their habitat. Short-term impacts to habitat may include minimal disturbance of the sediment where the channels are dredged for barge access and where individual bridge piers are constructed. Long-term impacts to marine mammal habitat will be limited to the footprint of the piles and the obstruction they will create following installation. However, this impact is not considered significant as the marine mammals can easily swim around the piles of the new bridge, as they currently swim around the existing bridge piers.

Mitigation

The following mitigation measures are required under the IHA to reduce impacts to marine mammals to the lowest extent practicable.

Barrier Systems

An air bubble curtain system is required to be used only when driving the permanent open-water piles at Piers E3 - E6 of Skyway and Piers E1 and E2 of the Self-Anchored Suspension (SAS) span. While the bubble curtain is required specifically as a method to reduce impacts to endangered and threatened fish species in SFB, it may also provide some benefit to marine mammals. The NMFS' Biological Opinion and the California Department of Fish and Game's (CDFG) 2001 Incidental Take Permit also allow for the use of other equally effective methods, such as cofferdams, as an alternative to the air bubble curtain system to attenuate the effects of sound pressure waves on fish during driving of permanent in-Bay piles (NMFS 2001; CDFG, 2001). Piers E-16 through E-7 for both the eastbound and westbound structures of the Skyway will be surrounded by sheet-pile cofferdams, which will be de-watered before the start of pile driving. De-watered cofferdams are generally effective sound attenuation devices. For Piers E3 through E6 of the Skyway and Piers 1 and E2 of the Self-Anchored Suspension span, it is anticipated that cofferdams will not be used; therefore, a bubble curtain will surround the piles.

Sound Attenuation

As a result of the determinations made during the Pile Installation Demonstration Project (PIDP) restrike and the investigation at the Benicia-Martinez Bridge, NMFS determined in 2003 that CALTRANS must install an air bubble curtain for pile driving for the open-water piles without cofferdams located at the SF-OBB. This air bubble curtain system consists of concentric layers of perforated aeration pipes stacked vertically and spaced no more than five vertical meters apart in all tide conditions. The minimum number of layers must be in accordance with water depth at the subject pile: 0-