SUPPLEMENTARY INFORMATION:

MMPA Background and Determinations

The MMPA prohibits the “take” of marine mammals, with certain exceptions. Among the exceptions is section 101(a)(5)(D) of the MMPA (16 U.S.C. 1361 et seq.) which directs the Secretary of Commerce (as delegated to NMFS) to allow, upon request, the incidental, but not intentional, taking by harassment 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 the public has an opportunity to comment on the proposed IHA.

Specifically, NMFS shall issue an IHA if it 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 taking for subsistence uses (where relevant). Further, NMFS must prescribe the permissible methods of taking and other “means of effecting the least [practicable] adverse impact” on the affected species or stocks and their habitat, paying particular attention to rookeries, mating grounds, and areas of similar significance, and on the availability of such species or stocks for taking for certain subsistence uses (referred to here as “mitigation”). NMFS must also prescribe requirements pertaining to the monitoring and reporting of such takings. The definitions of key terms, such as “take,” “harassment,” and “negligible impact,” can be found in the MMPA and the NMFS' implementing regulations (see 16 U.S.C. 1362; 50 CFR 216.103).

On July 25, 2024, a notice of NMFS' proposal to issue two IHAs to the USCG for take of marine mammals incidental to pile driving (installation and removal) associated with construction of two FRC homeporting docks in Seward and Sitka, Alaska, was published in the Federal Register (89 FR 60359). On December 20, 2024, NMFS published a Federal Register notice announcing the issuance of the IHAs to the USCG, one for Moorings Sitka effective from September 1, 2026, through August 31, 2027, and one for Moorings Seward effective from March 1, 2027, through February 29, 2028 (89 FR 104090).

On April 2, 2026, a notice of NMFS' proposal to modify the IHA for Moorings Sitka was published in the Federal Register (91 FR 16672). In that notice, NMFS indicated the estimated numbers, type, and methods of incidental take proposed for each species or stock, as well as the mitigation, monitoring, and reporting measures that would be required should the modified IHA be issued. The Federal Register notice also included analysis to support NMFS' preliminary conclusions and determinations that the modified IHA, if issued, would satisfy the requirements of section 101(a)(5)(D) of the MMPA for issuance of the IHA. The Federal Register notice included web links to a draft modified IHA for review, as well as other supporting documents.

No comments were received during the public comment period. With the exception of the minor changes described below, there are no changes to the specified activity, the species taken, the proposed numbers, type, or methods of take, or the mitigation, monitoring, or reporting measures in the proposed IHA notice. No new information that would change any of the preliminary analyses, conclusions, or determinations in the proposed IHA modification notice has become available since that notice was published, and therefore, the preliminary analyses, conclusions, and determinations included in the proposed IHA modification are considered final.

Changes From the Proposed IHA to the Final IHA

Since publication of the proposed IHA modification, the applicant has changed the fender piles planned for use from 16-inch (40.64-centimeter (cm)) steel piles to 14- to 16-inch (35.6- to 40.64-cm) plastic piles. The quantity of fender piles to be installed (60) and installation method (vibratory) remain the same, as does the maximum numbers of fender piles that will be installed per day (8). The time required to install the fender piles will decrease from 30 minutes to 15 minutes per pile, and the installation rate will increase from 5 piles per day to 6 piles per day. The sound source level for 14- to 16-inch plastic piles is 162 decibels referenced to 1 microPascal at 10 meters (dB re 1 µPa at 10 m) root-mean-square sound pressure level (RMS SPL), which is a decrease of 1 dB from the 16-inch steel piles proposed for use as fender piles. Therefore, the calculated distances to the Level A and Level B harassment zones sizes will be smaller than what was included in the notice of proposed IHA modification (91 FR 16672, April 2, 2026). The ensonified areas were not directly used in the calculation of estimated take because take was estimated with species occurrence data instead of density. Thus, there is no change to estimated take as a result of the slightly smaller Level A and Level B harassment zones. The USCG will use the same mitigation, monitoring, and reporting measures, including the shutdown and harassment zones, shown in the notice of proposed IHA modification and as described in the Marine Mammal Monitoring Plan. The take estimates included in the notice of proposed IHA modification remain the same. The change of pile type has been reflected in table 2 of the IHA.

NMFS has also revised the distribution of take across killer whale ( Orcinus orca) stocks expected in the project area. In the notice of proposed IHA modification, the percent of each stock impacted for killer whales was estimated assuming each stock was taken in proportion to its population size from the total take. We found that methodology was flawed because stock size and regional occurrence are not directly proportionate. Given the lack of data available on site-specific stock occurrence, we assume that all takes (106 takes by Level B harassment only) could occur to each stock of killer whale. As described in the Small Numbers section of the notice of proposed IHA modification (91 FR 16672, April 2, 2026) and herein, NMFS determined the amount of take authorized is below one-third of the estimated stock abundance of all killer whale stocks (table 1). For all stocks ( printed page 50810) other than the Eastern North Pacific Northern Resident stock of killer whale, the number of takes proposed for authorization would be considered small relative to the relevant stocks' abundances, even in the unlikely scenario that each estimated taking occurred to a new individual.

The Eastern North Pacific Northern Resident stock of killer whale occurs from Washington State through part of Southeast Alaska. Movements of killer whales, for both transient and resident stocks, between widely separated geographical areas have been documented; however, given the relatively sheltered location of the project site in Southeast Alaska, it is unlikely that numerous discrete groups of individuals sufficient to exceed one-third of the stock abundance would occur within the immediate vicinity of the project. It is more likely that individual groups that occur in the area would remain for periods of time and potentially be resighted on multiple days. As such, and given that the authorized takes would be allocated among four distinct killer whale stocks, the numbers of individuals taken would likely comprise less than one-third of the best available population abundance estimate of the Eastern North Pacific Northern Resident stock of killer whale.

Finally, a rounding error in the calculation of estimated take by Level B harassment of humpback whales was corrected to 60 takes by Level B harassment, which is a reduction of 1 take from the estimated take of marine mammals in the proposed authorization. This correction led to a reduction in the number of estimated takes of the Hawai'i stock of humpback whales by 1, thus, the authorized take of the Hawai'i stock of humpback whales is 59 takes by Level B harassment.

National Environmental Policy Act

To comply with the National Environmental Policy Act of 1969 (NEPA) (42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, NMFS must review our proposed action ( i.e., the issuance of an IHA) with respect to potential impacts on the human environment.

This action is consistent with categories of activities identified in Categorical Exclusion B4 (IHAs with no anticipated serious injury or mortality) of the Companion Manual for NAO 216-6A, which do not individually or cumulatively have the potential for significant impacts on the quality of the human environment and for which we have not identified any extraordinary circumstances that would preclude this categorical exclusion. Accordingly, NMFS has determined that the issuance of the modification of the IHA continues to qualify to be categorically excluded from further NEPA review.

Endangered Species Act

Section 7(a)(2) of the Endangered Species Act of 1973 (ESA) (16 U.S.C. 1531 et seq.) requires that each Federal agency ensures that any action it authorizes, funds, or carries out is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of designated critical habitat. To ensure ESA compliance for the issuance of IHAs, NMFS consults internally whenever we propose to authorize take for endangered or threatened species, in this case with the NMFS Alaska Regional Office.

There are two marine mammal species (Western DPS Steller sea lion and Mexico-North Pacific stock of humpback whale) with confirmed occurrence in the project area that are listed under the ESA. The NMFS Alaska Regional Office Protected Resources Division issued a Biological Opinion on July 28, 2026, under section 7 of the ESA, on the issuance of an IHA modification to the USCG under section 101(a)(5)(D) of the MMPA by the NMFS Permits and Conservation Division. The Biological Opinion concluded that the proposed action is not likely to jeopardize the continued existence of Western DPS Steller sea lion or Mexico North Pacific stock of humpback whale, and is not likely to destroy or adversely modify critical habitat for Western DPS Steller sea lion or Mexico North Pacific stock of humpback whale.

Authorization

Accordingly, consistent with the requirements of section 101(a)(5)(D) of the MMPA, NMFS has issued a modified IHA to the USCG for authorization to take marine mammals incidental to construction of a FRC homeporting dock in Sitka.

91 FR 50808