This Regulatory Impact Review (RIR) evaluates the costs and benefits of a proposed regulatory amendment to relax a harvest restriction for participants in the harvest limit area (HLA) Atka mackerel fishery in the Aleutian Islands. The proposed action would allow participants in the HLA fishery to harvest Atka mackerel outside of the HLA during the first assigned HLA fishery. Regulations currently prohibit harvest of any groundfish other than Atka mackerel, and then only within the HLA, during the first HLA fishery. This action would relieve a restriction on participants in the HLA Atka mackerel fishery and potentially provide additional protection for Steller sea lions by allowing for less harvest from within the HLA. The regulatory amendment would allowmore efficient harvest of Atka mackerel. This RIR addresses the requirements of Presidential Executive Order 12866.