Record of Decision for the Final Environmental Impact Statement for North Pacific Acoustic Laboratory Project

AGENCY:

Department of the Navy, DOD.

ACTION:

Notice of record of decision.

SUMMARY:

Pursuant to section 102(2)(c) of the National Environmental Policy Act (NEPA) of 1969, 42 U.S.C. section 4321 et seq., the regulations of the Council on Environmental Quality that implement NEPA procedures, 40 CFR parts 1500-1508, and Navy regulations implementing NEPA procedures (31 CFR 775); the Department of the Navy announces its decision to conduct the North Pacific Acoustic Laboratory (NPAL) project, which will entail resumption of transmissions from a sound source off the north coast of Kauai for five years. The action will be accomplished as described in the Final Environmental Impact Statement's (FEIS) preferred alternative, denoted “Continued Operation of the Kauai Sound Source.” The Navy was the lead agency and the National Marine Fisheries Service (NMFS) was a cooperating agency in the Environmental Impact Statement (EIS) process.

Background: The action will be conducted by Scripps Institution of Oceanography of the University of California, San Diego (Scripps), which carried out the first phase of Acoustic Thermometry of Ocean Climate (ATOC) feasibility research, and by the Applied Physics Laboratory of the University of Washington. Funding will be provided by the Office of Naval Research (ONR). Based on the success of the ATOC effort, the Navy recognizes the opportunity to transition into a second phase of research, NPAL, which will use the same acoustic source that was used in the Kauai ATOC program.

The purposes of the NPAL project are to study the feasibility and value of large scale acoustic thermometry; to study the behavior of sound transmissions in the ocean over long distances; and to study the possible long-term effects of sound transmission on marine life.

Under this action, the seabed power cable and sound source will remain in their present locations, and transmissions will continue with approximately the same signal parameters and transmission schedule used in the ATOC project. NPAL transmissions will consist of six 20-minute transmissions (one every four hours), every fourth day, with each transmission preceded by a five minute ramp-up period during which the signal intensity will be gradually increased. This represents an average duty cycle of two percent. With the possible exception of short duration testing with duty cycles of up to eight percent, or equipment failure, this schedule will continue for a period of five years. The signals transmitted by the source will have a center frequency of 75 Hertz (Hz) and a bandwidth of approximately 35 Hz. Approximately 260 watts of acoustic power will be radiated during transmission. At one meter from the source, the sound intensity will be about 195 decibels (dB) referenced to the intensity of a signal with a sound pressure level of one microPascal on a “water standard” basis. These signal parameters and source level were found during the ATOC project to provide adequate, but not excessive, signal-to-noise ratios at the receiver ranges of interest.

At the conclusion of the five-year period, the seabed power cable will be abandoned in place. This will have the benefits of avoiding disturbance of sensitive military instrumentation in the vicinity and the benthic environment. The source will also be abandoned in place unless it appears to be in sufficiently good condition to warrant recovery.

Alternatives: A screening process, based upon criteria set in the EIS, was conducted to identify a reasonable range of alternatives that would satisfy the Navy's purpose and need, while minimizing environmental impacts.

Seven alternatives were initially considered: (1) The preferred alternative described above; (2) a no-action alternative; (3) additionally restricting source transmission times and modifying source operational characteristics; (4) using an alternate site for the project; (5) using a moored autonomous sound source; (6) the use of alternate sensors such as satellites; and (7) use computer modeling without collection of real-world data. Four of these alternatives, additionally restricting source transmission times and modifying source operational characteristics, moored autonomous source, alternate sensors, and modeling, were eliminated because they would not have met the desired research objectives. The other three alternatives, the preferred alternative, no action, and an alternate project site (Midway Island), were analyzed in detail.

The preferred alternative involves the continued operation for five additional years of the low frequency sound source (including the seabed power cable) previously installed off the north shore of Kauai, Hawaii, for use in the ATOC research, as described in detail above. This alternative best meets the project objectives for the three components of NPAL. The sound source at Kauai would provide superior acoustic capability for study of both large scale acoustic thermometry and long-range underwater sound transmission. In addition, further studies of the marine mammal species in the vicinity of the Kauai source would be able to build on the data collected during the Kauai ATOC Marine Mammal Research Program (MMRP). A sound source at Midway (alternate project site—Midway Island alternative) would have a more limited acoustic capability and limited baseline marine animal data while the no action alternative would offer no possibility for a long-term research project exploring underwater sound transmission and the natural and man-made changes in the ocean environment. Therefore, continued operation of the Kauai source (preferred alternative) best meets the project objectives.

The preferred alternative is considered the most environmentally benign alternative. As described in detail in the EIS, the environment includes the following major resources: physical, biological, economic, and social. Physical effects include those from construction and/or removal of facilities and potential increases in ambient noise. The physical installations at Midway Island, as part of the Midway alternative would be relatively minor and generally are benign from an environmental standpoint. The no action and Midway alternatives would involve the removal of the sound source and cable presently in place off northern Kauai. Removing the cable is likely to disrupt the seafloor environment and any new coral that may have begun to grow on the cable. The preferred and Midway alternatives would add somewhat to the ambient noise levels during transmission periods. The comparative potential biological effects of the preferred and Midway alternatives depend on the relative abundance of sensitive animals at the respective locations. For source transmissions, these differences would be minimal. However, there exists the potential at Midway for disturbance of breeding and pupping of highly endangered Hawaiian monk seals during installation of the power cable. The preferred and Midway alternatives would have comparable socioeconomic effects. The no action alternative would not have any socioeconomic effects. Therefore, the preferred alternative is the most environmentally benign alternative.

Environmental Impacts: Potential environmental impacts of continuing transmission of the sound source installed north of Kauai were analyzed in the Environmental Consequences section of the EIS. Several potential effects due to source transmissions were discussed, including the potential for physical auditory effects, behavioral disruption, habituation, masking, long-term effects, and indirect effects. Analysis of potential effects on marine mammals was accomplished with results from the California and Hawaii ATOC MMRPs and a program of underwater acoustical modeling. Neither MMRP observed any overt or obvious short-term changes in behavior, abundance, distribution, or vocalization in the marine mammal species studied. Intense statistical analyses revealed some subtle changes in the distance and time between successive humpback whale surfacings, and in the distribution of humpback whales away from the Kauai source and humpback (and possibly sperm) whales away from the California source during transmission periods. Bioacoustic experts concluded that these subtle effects would not adversely affect the survival of an individual whale or the status of the North Pacific humpback whale population (Frankel and Clark, 2000).

Mitigation: The following mitigation measures discussed in the FEIS will be employed to minimize the potential effects of the NPAL sound source:

1. Sound source will operate at the minimum duty cycle necessary to support the large-scale acoustic thermometry and long-range propagation objectives.

2. Any increases in the duty cycle beyond the two percent, with a maximum of eight percent, will not occur during the peak season for humpback whale presence in the vicinity of the Kauai sound source. (January-April).

3. Sound source will operate at the minimum power level necessary to support large-scale acoustic thermometry and long-range sound transmission objectives.

4. Transmissions from the NPAL sound source will be preceded by a five-minute ramp-up of the source power.

5. All NPAL vessels and aircraft will be equipped with required air pollution controls.

6. The source cable and possibly the sound source, will not be removed at the end of the experiment.

The feasibility and desirability of limiting sound transmissions to times when potentially vulnerable species are not present in the vicinity of the source and modifying source characteristics to potentially reduce effects on marine animals was considered as an initial alternative. Limiting source transmissions to seasons when humpback whales, the most abundant of the potentially vulnerable species in the Kauai area, are not present would severely reduce the utility of both the acoustic thermometry and long-range propagation studies, as well as make it essentially impossible to study the possible long-term effects of low frequency sound transmissions on marine life. Operational characteristics important to potential effects on marine animals include frequency, source power level, waveform, and sound signal transmission length. Each of these characteristics has been selected for the least potential environmental impact and the maximum scientific utility. Results from the ATOC study demonstrate that these source characteristics provide adequate, but not excessive, signal-to-noise ratios at the receiver ranges of interest.

Because subtle effects detected by the ATOC MMRPs were found only after intense statistical analysis, the conduct of further marine mammal monitoring studies is based on the advancement of the understanding of the potential for long-term effects from acoustic transmissions. The following monitoring measures will be in place:

1. Conduct eight aerial surveys from February through early April, eight days apart, to match the NPAL transmission schedule. Annual reports of the monitoring and studies will include numbers and locations of marine mammal and sea turtle sightings, which would be submitted to NMFS, with copies to the Hawaii Department of Land and Natural Resources, the Office of Planning and the Hawaiian Island Humpback Whale National Marine Sanctuary. The effort will continue to monitor for acute short-term effects, although none were observed during the ATOC MMRPs.

2. Monitor marine mammal data by coordinating with the local marine mammal stranding network to detect any long-term trends.

In the Biological Opinion (BO), NMFS recommended investigating the effects of masking by low frequency anthropogenic sounds on baleen whales through studies of similar species that are sensitive to low frequency sound, as a conservation recommendation. The only marine mammal species that regularly occur off Hawaii and vocalizes in the same frequency range as the NPAL transmissions, and thus could potentially be masked if positioned close to the acoustic source, is the humpback whale. Since it is nearly impossible to capture a humpback whale or another baleen whale and conduct masking studies, and there are no other similar species that are sensitive to low frequency sound that regularly occur off Hawaii, the NPAL project will not focus its marine mammal monitoring and studies on this issue. However, the Navy has sponsored and is continuing to sponsor, other researchers whose work focuses on clarifying the potential effects of anthropogenic sounds on marine mammals, including the effects of masking by low frequency sounds (e.g., Nachtigall et al., 2001; Schlundt et al., 2000; Kastak and Schusterman, 1998).

Coordination and Consultation With NMFS: In addition to acting as a cooperating agency in the EIS process, NMFS has a regulatory role in its jurisdiction over issues related to endangered species and marine mammals. The potential effect upon listed species required consultation with NMFS under section 7 of the Endangered Species Act. ONR initiated interagency consultation on June 23, 2000 by submitting a Biological Assessment to NMFS. Consultation concluded with NMFS' issuance of a BO on April 26, 2001. Based on the status of the species, environmental baseline, effects of the action, and cumulative effects, NMFS concluded that the proposed action is not likely to jeopardize the continued existence of the endangered humpback, fin, sei, blue, right, and sperm whales or the Hawaiian monk seal, or result in the destruction or adverse modification of critical habitat considered in the BO.

NMFS also administers the Marine Mammal Protection Act. Scripps, in coordination with NMFS, is pursuing a Letter Of Authorization (LOA) for incidental taking by harassment under 16 U.S.C. 1371. With the publication of the draft EIS, Scripps began the process of applying for a LOA. NMFS published an Advance Notice of Proposed Rulemaking on August 24, 2000 (65 FR 51584), and a Proposed Rule on December 22, 2000 (65 FR 80815). A Final Rule was published on August 17, 2001 (66 FR 43442).

Response to Comments Received Regarding the FEIS: After the FEIS was distributed for a 30-day public review period which ended June 25, 2001, Scripps/ONR received 3 letters. From the state of Hawaii Department of Land and Natural Resources was a letter concurring with the “no effect” determination regarding National Historic Preservation Act Review, section 106 Compliance. There was a “no additional comment” letter from the Department of the Army, U.S. Army Engineer District of Honolulu. The third comment pertained to a different Navy proposed action, the Low Frequency Active sonar, an action unrelated to the NPAL project.

Conclusion: Continued use of the previously installed sound source off the northern coast of Kauai is the alternative that best meets the project's purpose and need for large-scale acoustic thermometry and long-range underwater sound transmission studies. Selection of this, the preferred alternative, also best facilitates the planned marine mammal monitoring and studies, and also minimizes environmental impacts.

Based on the analysis contained in the FEIS, the administrative record, and other factors discussed above, I select the preferred alternative, Continued Operation of the Kauai Source, to implement the proposed action.