SUPPLEMENTARY INFORMATION:

We, the U.S. Fish and Wildlife Service (Service), announce the availability of a final environmental impact statement (EIS) for a proposed project to eradicate invasive, introduced house mice ( Mus musculus) on the South Farallon Islands of the Farallon Islands National Wildlife Refuge in California. This notice advises the public that the final EIS is now available to the public. The final EIS describes the alternatives identified to eradicate house mice from the South Farallon Islands and eliminate their negative impacts to the ecosystem of these islands.

National Environmental Policy Act

We are conducting environmental review for the proposed South Farallon Islands Invasive House Mouse Eradication Project in accordance with the requirements of the National Environmental Policy Act as amended (NEPA; 43 U.S.C. 4321 et seq.), its implementing regulations in 40 CFR 1500-1508, other applicable regulations, and our procedures for compliance with those regulations. On April 13, 2011, we published in the Federal Register a notice of intent to prepare an environmental impact statement (EIS) for the proposed project (76 FR 20706). We announced the availability of the draft EIS for public comment on August 16, 2013 (78 FR 50082). On October 25, 2013, we issued a revised draft EIS to clarify language on the population status of the ashy storm-petrel ( Oceanodroma homochroa) and revise the assessment of impacts to the ashy storm-petrel under the no action alternative (78 FR 64002). In accordance with 40 CFR 1506.6, we now announce the availability of the final EIS.

In addition to our publication of this notice, the U.S. Environmental Protection Agency (EPA) is publishing a notice announcing the final EIS, as required under section 309 of the Clean Air Act (42 U.S.C. 7401 et seq.). The publication date of EPA's notice of availability in the Federal Register is the start of the 30-day wait period required for the final EIS. (See EPA's Role in the EIS Process, below, for further information.)

We will make a decision on the alternatives presented in the EIS no sooner than 30 days after the publication of the final EIS. We anticipate issuing a Record of Decision (ROD) in June 2019.

Background

In 2009, the Service completed a Comprehensive Conservation Plan (CCP) and Environmental Assessment/Finding of No Significant Impact to guide the management of the Farallon Islands National Wildlife Refuge (Refuge) over a 15-year period. The wildlife management goal in the CCP is to protect, inventory, and monitor, as well as to restore to historic levels, breeding populations of 12 seabird species, 5 marine mammal species, and other native wildlife. One of the strategies identified to meet this goal is the eradication of the non-native invasive house mouse from the South Farallon Islands, and the prevention of future introduction of mice.

We now propose to eradicate invasive house mice from the South Farallon Islands. We expect that eradicating invasive mice will benefit native seabirds, amphibians, terrestrial invertebrates, plants, and wilderness quality, and will help restore natural ecosystem processes on the islands. The South Farallon Islands have sustained ( printed page 9549) ecological damage over many decades from the presence of invasive mice. Eradicating house mice would eliminate the last remaining invasive vertebrate species on the Refuge, thereby enhancing the recovery of this unique and sensitive ecosystem.

Alternatives

We analyzed three alternatives in this final EIS:

Alternative A: No-Action Alternative

Under this alternative, we would not take any action to eradicate mice from the South Farallon Islands, maintaining the status quo. Native species and wilderness would continue to be impacted by invasive mice. However, other ongoing invasive species management programs on the South Farallon Islands would continue based on previous agency decisions. Low-intensity mouse control, primarily snap-trapping, currently occurs within and around the residences and other buildings on Southeast Farallon Island. These localized control efforts would continue under the no-action alternative, but the mouse population on the rest of the South Farallon Islands would not be subject to control efforts.

Under this alternative, we would also continue management activities focused on conserving storm-petrels, native plants, and their habitat on the islands, including invasive plant control and storm-petrel nesting habitat management. The current biosecurity measures would continue under this alternative, but these measures still could leave the Farallones at risk of additional invasions by non-native animal species.

Alternative B: Aerial Broadcast of Brodifacoum-25D Conservation (Preferred Alternative)

Under this alternative, the project area would be treated with the rodent bait Brodifacoum-25D Conservation. This bait is a cereal grain-based pellet (about 1 gram each) containing the rodenticide brodifacoum (25 ppm, or 0.0025 percent). Brodifacoum is typically effective after just one feeding by a mouse. The primary delivery of the bait would be through two aerial applications, with hand baiting and bait stations as a likely secondary means of bait delivery in selected areas. Bait applications would be separated by 10 to 21 days. The applications would take place between the months of October and December, with a most likely application period of November-December. The overall operational period is expected to be about six weeks long. Mitigation measures in this alternative consist of avoidance and minimization actions to limit adverse impacts to natural and cultural resources. For example, project timing is scheduled to occur outside seabird and marine mammal breeding seasons and when most wildlife populations are near annual minimums. We would implement a comprehensive gull hazing program in order to minimize the exposure of gulls to rodent bait. We would also capture and hold or translocate raptors present on the islands just prior to and during bait application. For precaution, a sample of Farallon arboreal salamanders ( Aneides lugubris farallonensis) would be captured and held, then released back into the wild following bait degradation. To prevent bait drift into the marine environment, precision GPS techniques and a precision bait bucket will be utilized to keep bait application above the high tide line. Other mitigation measures include the possibility of using bait stations and hand broadcast of bait in certain high-risk areas, removing carcasses that may have been exposed to rodenticide, retrieving or crushing remaining rodent bait after it is no longer needed, minimizing wildlife disturbance during bait application, minimizing impacts to wilderness by using the minimum tools necessary for eradication, and protecting cultural resources during bait application. Monitoring of operational, mitigation, and ecosystem restoration objectives would be conducted before, during, and after the proposed mouse eradication. In addition, in order to minimize the risk of future rodent invasions, a biosecurity plan would be implemented prior to and in conjunction with the proposed eradication to prevent, detect and rapidly respond to potential future rodent incursions.

Alternative C: Aerial Broadcast of Diphacinone-50 Conservation

Under this alternative, the project area would be treated with the rodent bait Diphacinone-50 Conservation. This bait is a cereal grain-based pellet (about 1-2 grams each) containing the rodenticide diphacinone (50 ppm, or 0.0050 percent). Alternative C differs from Alternative B mainly in the type of rodenticide used for the proposed eradication, the number of applications that may be necessary, and the expected overall length of the operational period. To be effective, diphacinone requires multiple feedings by a mouse over several days. Under Alternative C, Diphacinone-50 Conservation would be broadcast primarily by helicopter, likely with some hand baiting and bait stations used in selected areas. The bait application would take place between the months of October and December, with most likely application in the November-December period. However, under Alternative C, we would need to broadcast a portion of the total amount of bait required during three applications, each separated by approximately 7 days. The overall operational period is expected to be about 16 weeks long. Alternative C would include the same mitigation measures described under Alternative B, as well as the monitoring program and the biosecurity plan.

EPA's Role in the EIS Process

The EPA is charged, under section 309 of the Clean Air Act, to review all Federal agencies' EISs and to comment on the adequacy and the acceptability of the environmental impacts of proposed actions in the EISs.

EPA also serves as the repository for EISs prepared by Federal agencies and provides notice of their availability in the Federal Register . The Environmental Impact Statement Database provides information about EISs prepared by Federal agencies, as well as EPA's comments concerning the EISs. All EISs are filed with EPA, which publishes a notice of availability on Fridays in the Federal Register .

The notice of availability is the start of the 30-day “wait period” for final EISs, during which agencies are generally required to wait 30 days before making a decision on a proposed action. For more information, see https://www.epa.gov/​nepa. You may search for EPA comments on EISs, along with EISs themselves, at https://cdxnodengn.epa.gov/​cdx-enepa-public/​action/​eis/​search.