E6-9679. Taking of Marine Mammals Incidental to Specified Activities; Geophysical Surveys in South San Francisco Bay South of the Dumbarton Bridge

AGENCY:

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

ACTION:

Notice of proposed authorization for an incidental take authorization; request for comments.

SUMMARY:

NMFS has received a request from the URS Corporation (URS) for an authorization to take small numbers of California sea lions, Pacific harbor seals, harbor porpoises, and gray whales, by harassment, incidental to geographical seismic surveys being conducted by Fugro West, Inc. (Fugro), in south San Francisco Bay. Under the Marine Mammal Protection Act (MMPA), NMFS is requesting comments on its proposal to issue an authorization to Fugro to incidentally take, by harassment, small numbers of these species of pinnipeds and cetaceans during the next 12 months.

DATES:

Comments and information must be received no later than July 20, 2006.

ADDRESSES:

Comments on the application and draft Environmental Assessment (EA) should be addressed to P. Michael Payne, Chief, Permits, Conservation and Education Division, Office of Protected Resources, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910-3225, or by telephoning the contact listed here. The mailbox address for providing e-mail comments is [e-mail]. Include in the subject line of the e-mail comment the following document identifier: 050106A. Comments sent via e-mail, including all attachments, must not exceed a 10-megabyte file size. A copy of the application, the application letter, EA, and other related documents may be obtained by writing to this address or by telephoning one of the contacts listed here (see FOR FURTHER INFORMATION CONTACT) and is also available at: http://www.nmfs.noaa.gov/​pr/​permits/​incidental.htm.

FOR FURTHER INFORMATION CONTACT:

Shane Guan, NMFS, [phone], ext 137, or Monica DeAngelis, NMFS, [phone].

SUPPLEMENTARY INFORMATION:

Background

Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) direct the Secretary of Commerce to allow, upon request, the incidental, but not intentional, taking of small numbers of marine mammals by U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified geographical region if certain findings are made and either regulations are issued or, if the taking is limited to harassment, notice of a proposed authorization is provided to the public for review.

An authorization shall 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 that the permissible methods of taking and requirements pertaining to the mitigation, 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 March 30, 2006, URS on behalf of Fugro submitted an application to NMFS requesting an Incidental Harassment Authorization (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 conducting geophysical surveys in the south San Francisco Bay (SFB or the Bay), California. The purpose of the surveys is to aid the San Francisco Public Utility Commission (SFPUC) in the design of an underground water pipeline, the Bay Division Tunnel, in south SFB.

The proposed seismic study would span from Newark Slough and Plummer Creek adjacent to the Cargill Salt property in the east, to the Ravenswood Baylands open space on the western shore of SFB. The study would roughly parallel the existing SFPUC trans-bay pipelines, approximately 1 mile south of the Dumbarton Bridge. Marine seismic surveys would take approximately 8 - 10 days to perform. In the Newark Slough and Plummer Creek areas, work would be restricted to the non-pupping seasons of the harbor seal (July 1 - November 30). The ideal start date would occur during the summer/fall of 2006.

The proposed geophysical (seismic) studies would include 21 seismic sample transects. A total of 25 - 35 linear miles (40 - 56 km) of marine-based geophysical sampling would occur. The marine seismic reflection data would be collected along a series of lines that cross the Bay centered over the projected alignment. A centerline and four wing lines are planned. Cross lines, or tie lines, would be run perpendicular to the centerline and extend 200 - 500 m (656 - 1,640 ft) beyond the alignment parallel lines, unless restricted by water depth or man-made obstructions. Water depths in the survey area range from roughly 14 m (45 ft) in the deeper mid-Bay channel to about 1.8 - 2.4 m (6 - 8 ft) along the shore and in Newark Slough at high tide. Work would be conducted at high tide in the shallow nearshore areas.

Data would be collected from a small boat that tows a seismic energy source and a multichannel hydrophone. Two energy sources would be used, a Squid “minisparker” system and a Geopulse “boomer” system. An onboard generator powers the energy sources. The hydrophone contains multiple sensors that detect the seismic waves reflected from the water bottom and subsea floor sediments and rocks. The hydrophone is filled with inert silicon oil.

The survey boat would travel along predetermined survey lines using a differential global positioning system (DGPS) for navigation. Boat speed during surveys would be at 3 - 4 knots. The length of time for each survey transect will vary depending on the total distance of the transect. The longest transects spanning from east to west would take about 1 hour to complete. The shorter north-south transect would generally take less than 30 minutes to complete.

The energy source would be fired every 1/2 second (boomer) or 1 second (minisparker). Data received by the hydrophone are recorded with an onboard seismograph and laptop computer. Sound pressure level from a boomer operating at 350 joules is 204 dB re 1 microPaRMS at 1 m, and from a minisparker is 209 dB re 1 microPaRMS at 1 m. Frequency range for the boomer is at 750 - 3,500 Hz, with pulse duration 0.1 ms; and frequency range for the minisparker is at 150 - 2,500 Hz, with pulse duration 0.8 ms.

Description of the Marine Mammals Potentially Affected by the Activity

The marine mammals most likely to be found in SFB are the California sea lion, Pacific harbor seal, and harbor porpoise. From December through May, gray whales may also be present in the Bay. General information of these species can be found in Caretta et al. (2005), 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. Additional information on these species is presented below.

Pacific harbor seal

Within the proposed project area, Pacific harbor seals are know to haul-out near the junction of Newark Slough and Plummer Creek. Newark Slough is a continually used seal haul-out site, although it is used by small numbers of harbor seals compared with Mowry Slough to the south and Yerba Buena Island and Castro Rocks in the North Bay. Harbor seals are also known to utilize Newark Slough as a pupping site (Harvey and Oates, 2002) and up to 82 individuals have been documented hauling-out at that location on a single day. During a five-year survey period between 2000 and 2005 at Newark Slough, an average of 42 individuals were counted each year during the pupping season, compared to Mowry Slough 2 miles to the south, where an average of 279 animals were counted each year during the pupping season. The California stock of harbor seal is the only stock of this species found in the proposed project area, and its abundance is estimated to be 27,863 (Carretta et al., 2005).

California sea lion

California sea lions breed off the Central and Southern California coastline. Once the pupping season is completed (May - June), male sea lions migrate north and enter the Bay. Although California sea lions are mainly known for haul-out sites off the San Francisco and Marin shorelines within the Bay, it is possible for this species to forage in the south Bay area as well. The U.S. stock of the California sea lion population is estimated between 237,000 to 244,000 (Carretta et al., 2005).

Gray whale

In the past, eastern Pacific gray whales have been seen irregularly in SFB. These individuals likely wandered off the migration route. The number of gray whales observed in the Bay increased in 1999 and 2000, and the observed whales apparently were feeding in a number of areas in May and June. The increased aberrancies of gray whale sightings in timing and location, along with foraging activities on its migration route in 1999 and 2000, were potentially caused by a significant decline in amphipod density in gray whale's feeding ground in the Bering and Chukchi seas (Le Boeuf et al., 2000). Although twice being hunted to the brink of extinction in the mid 1800s and again in the early 1900s, the eastern North Pacific gray whales population has since increased to a level that equals or exceeds pre-exploitation numbers (Jefferson et al., 1993). Angliss and Lodge (2004) reported the latest abundance estimate of this population is 26,635.

Harbor porpoise

Harbor porpoises found in waters off the coast of central California from San Francisco to Point Arena belong to the San Francisco-Russian River stock. Year-round surveys in the Gulf of the Farallones area have shown harbor porpoise occurrence within 10 - 20 km (6 - 12 miles) of San Francisco Bay (Calambokidis et al., 1990). High harbor porpoise sightings were also reported just outside the Golden Gate and about 1 km (0.62 mile) inside SFB, however, the occurrence of harbor porpoises in the southern part of Bay is rare (DeAngelis, personal comm. 2006). Based on Carretta et al. (2005), the estimated abundance of the San Francisco-Russian River stock of harbor porpoise is 8,521.

Potential Effects on Marine Mammals and Their Habitat

Seismic surveys using acoustic energy may have the potential to adversely impact marine mammals in the vicinity of the activities (Gordon et al., 2004). Intense acoustic signals from seismic surveys have been known to cause behavioral alteration such as reduced vocalization rates (Goold, 1996), avoidance (Malme et al., 1986, 1988; Richardson et al., 1995; Harris et al., 2001), and changing in blow rates (Richardson et al., 1995) in several marine mammal species.

The proposed studies would use a low intensity acoustic energy with source levels of 204 dB re 1 microPa at 1 m RMS (boomer) and 209 dB re 1 microPa at 1 m RMS (minisparker) to conduct the seismic surveys. However, it is unlikely that any marine mammals in the vicinity would be exposed to high sound pressure levels (SPL) due to transmission loss of the acoustic energy in the water column. In addition, the sound pulses produced by the energy sources are extremely short, lasting for only 0.1 ms for the boomer and 0.8 ms for the minisparker. Therefore, the energy from the seismic impulse is expected to be significantly low.

Pinniped disturbance could also be caused by the presence of vessels and humans that are involved in the geographical surveys. These disturbances could cause hauled out harbor seals or California sea lions to flush and possibly result in temporary use of alternate haul-out sites in the Bay. However, long term abandonment of the sites is not likely because noise from traffic, recreational boaters, and other human activities already occur in the area, and it is likely that these animals have become habituated to these disturbances.

Furthermore, marine mammal densities within the proposed project are typically very low. California sea lions, harbor porpoises and gray whales are not known to regularly visit the proposed project area, which is located in southern SFB. Although harbor seals use portions of the proposed project area as haul-out sites, their density is low. Within the last 5 years, individual harbor seals counted while hauling-out at the Newark Slough haul-out site during the post-pupping season have fluctuated between a maximum of 34 animals in 2001 to a minimum of 10 animals in 2005 (DeAngelis, personal comm. 2006). Numbers of harbor seals counted at the Newark Slough haul-out site during May 2001 and May 2002 (pupping season) ranged from 26 - 65 individuals. Lastly, the entire geophysical survey would only last for 8 - 10 days, which excludes any possible long term noise exposure to marine mammals in the vicinity of the proposed action area.

Based on this information, NMFS concludes that a small number of Pacific harbor seals, California sea lions, harbor porpoises, and gray whales that may be swimming, foraging, or resting in the project vicinity would be potentially taken by Level B behavioral harassment due to the proposed activity. In addition, proposed mitigation measures discussed below would greatly reduce the potential takes of marine mammals due to the proposed geophysical surveys.

Mitigation

The following mitigation measures are proposed be required under the proposed IHA to be issued to SFPUC for conducting geophysical surveys in southern SFB. NMFS believes that the implementation of these mitigation measures would reduce impacts to marine mammals to the lowest extent practicable.

Time and Location

Geophysical studies would only be conducted during daylight hours from 7 am - 7 pm, when marine mammal monitoring prior to and during the surveys would be most effective.

Seismic studies would not occur in the vicinity of Newark Slough or Plummer Creek during the harbor seal pupping season (March 1 - June 30). Seismic studies would only occur over open water transects during that period.

Establishment of Safety Zones

Safety zones would be established and monitored during the seismic surveys. The applicant proposes to establish a 45-m (148-ft) radius safety zone for the boomer system and a 100-m (328-ft) radius for the minisparker system. At these distances, the SPLs would be reduced to 179 dB re 1 microPa rms and 169 dB re 1 microPa rms, respectively, which is lower than NMFS standards set for avoiding marine mammal Level A harassment (180 dB re 1 microPa rms for cetaceans and 190 dB re 1 microPa rms for pinnipeds).

Observers on boats will survey the safety zone for 15 minutes to ensure that no marine mammals are seen within the zone before a seismic survey begins. If marine mammals are found within the safety zone, seismic surveys will be delayed until they move out of the area. If a marine mammal is seen above the water and then dives below, the surveyor will wait 15 minutes and if no marine mammals are seen by the observer in that time it will be assumed that the animal has moved beyond the safety zone. This 15-minute criterion is based on scientific evidence that harbor seals in San Francisco Bay dive for a mean time of 0.50 minutes to 3.33 minutes (Harvey and Torok, 1994), the mean diving duration for harbor porpoises ranges from 44 to 103 seconds (Westgate et al., 1995), and the mean diving duration for gray whales is approximately 1.84 minutes (Wursig et al., 2003).

Soft Start

Although marine mammals will be protected from Level A harassment by establishment of a safety zone at a SPL levels of 169 and 179 dB re 1 microPa rms, mitigation may not be 100 percent effective at all times in locating marine mammals. In order to provide additional protection to marine mammals near the project area by allowing marine mammals to vacate the area prior to receiving a potential injury, and to further reduce Level B harassment by startling marine mammals with a sudden intensive sound, Fugro will implement “soft start” practice when starting up acoustic equipment. By implementing the “soft start” practice, acoustic equipment will be initiated at an energy level less than full capacity (i.e., approximately 40-60 percent energy levels) for at least 5 minutes before gradually escalating to full capacity. This would ensure that, although not expected, any pinnipeds and cetaceans that are missed during safety zone monitoring will not be injured.

Equipment Shut-down If Marine Mammal Enters Safety Zone

With all the aforementioned mitigation measures in place, marine mammals may still enter the safety zone when geophysical surveys are underway. As a result, there is a possibility that Level A harassment could occur to these animals when exposed to intensive sounds. In order to prevent any potential Level A harassment to marine mammals from occurring, the surveyors will shut down the acoustic equipment if a marine mammal is sighted in or believed to have entered within the safety zone during the survey transect. The surveyors would not start the acoustic equipment again until the marine mammal leaves the safety zone, or no marine mammals are sighted within the safety zone for 15 minutes after the last sighting.

Monitoring and Reporting

URS will develop a monitoring plan that would collect data for each distinct marine mammal species observed in the south Bay proposed project area during the period of the seismic surveys. Marine mammal behavior, overall numbers of individuals observed, frequency of observation, the time corresponding to the daily tidal cycle, and any behavioral changes due to the geophysical surveys will be recorded on daily observation sheets.

Monitoring would be conducted by qualified NMFS-approved biologists. Binoculars and optical or digital laser range finders that are accurate to 3 feet (0.9 m) would be standard equipment for the monitors.

Monitoring would begin prior to the first day of the survey to establish baseline data, and would occur from a chase boat during the 8 - 10 day survey period. Post-survey monitoring would occur for a period of one day upon completion of the seismic studies.

Before the startup of the survey equipment, a marine mammal observer would visually survey the area for 15 minutes to confirm the safety zone is clear of any marine mammals. Seismic surveys will not begin until the safety zone is clear of marine mammals. Two observers would be present when surveys start onboard a separate boat and scan different sections of the overall survey area, particularly the safety zone. However, as described in the Mitigation section, once seismic survey of a transect begins, operations will continue uninterrupted until that transect is completed. However, if seismic survey of one transect is completed and a marine mammal is sighted within the designated safety zone prior to commencement of the next transect, the observer(s) must notify the surveyor (or other authorized individual) immediately and follow the mitigation requirements as outlined previously (see Mitigation).

URS would submit a final report to NMFS 90 days after completion of the proposed project. The final report would include data collected for each distinct marine mammal species observed in the south Bay proposed project area during the period of the seismic surveys. Marine mammal behavior, overall numbers of individuals observed, frequency of observation, and any behavioral changes due to the geophysical surveys would also be included in the final report.

National Environmental Policy Act (NEPA)

NMFS has prepared a draft EA for public review and comment (see ADDRESSES).

Endangered Species Act (ESA)

Based on a review conducted by NMFS biologists, no ESA-listed species are expected to occur in the proposed action area, therefore, NMFS has determined that this action will have no effect on listed species, and a section 7 consultation is not necessary.

Preliminary Determinations

For the reasons discussed in this document and in the identified supporting documents, NMFS has preliminarily determined that the impact of seismic surveys and other activities associated in the south SFB would result, at worst, in the Level B harassment of small numbers of California sea lions, Pacific harbor seals, harbor porpoises, and potentially gray whales that inhabit or visit south SFB. While behavioral modifications, including temporarily vacating the area during the survey period of 8 - 10 days, may be made by these species to avoid the resultant visual and acoustic disturbance, the availability of alternate areas within SFB and haul-out sites (including pupping sites) and feeding areas within the Bay has led NMFS to preliminarily determine that this action will have a negligible impact on California sea lions, Pacific harbor seals, harbor porpoises, and gray whale populations along the California coast.

In addition, no take by Level A harassment (injury) or death is anticipated and harassment takes should be at the lowest level practicable due to incorporation of the mitigation measures described in this document.

Proposed Authorization

NMFS proposes to issue an IHA to Fugro for the potential harassment of small numbers of harbor seals, California sea lions, harbor porpoises, and gray whales incidental to conducting of seismic surveys in south San Francisco Bay in California, provided the previously mentioned mitigation, monitoring, and reporting requirements are incorporated.

Information Solicited

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

Dated: June 14, 2006.

Donna Wieting,

Deputy Director, Office of Protected Resources, National Marine Fisheries Service.