The U.S. Fish and Wildlife Service proposes to issue a one-year Incidental Harassment Authorization (IHA) under the Marine Mammal Protection Act to the City and Borough of Sitka, Alaska, authorizing nonlethal Level B harassment of up to 36 northern sea otters (Southeast Alaska stock) incidental to construction of a new seaplane base on Japonski Island in Sitka Channel from July 2024 through July 2025. Construction involves pile driving, blasting, excavation, and fill placement. FWS preliminarily finds negligible impact on the stock (0.13% of 27,285 animals) and no unmitigable adverse impact on subsistence uses. A draft EA accompanies the proposed IHA; public comments are due June 6, 2024.