National Marine Fisheries Service proposes regulatory changes to improve the administration of the High Seas Fishing Compliance Act (HSFCA) program and facilitate the monitoring of U.S. flag vessels operating on the high seas. The proposed rule includes, for all high seas fishing vessels, adjustments to permitting and reporting requirements to provide for reviews of high seas fishing activities under environmental laws, particularly the Endangered Species Act and National Environmental Policy Act, prior to permitting such activities. It also includes requirements for the installation and operation of vessel monitoring system units, placement of observers on vessels, and reporting of transshipments on the high seas to fill, for high seas areas, gaps in the monitoring, control, and surveillance requirements not covered by other fisheries-related regulations. Although other existing regulations govern certain fishing activities on the high seas to varying degrees, this rule would establish a minimum standard to facilitate monitoring and surveillance of all U.S. vessels operating on the high seas. Establishing a minimum standard, and closing regulatory gaps, would facilitate enforcement of international conservation and management measures with respect to U.S. flag vessels. It is anticipated that these changes will not affect current levels of fishing activity by U.S. vessels issued HSFCA permits. Consequently, this proposed action is not expected to have adverse economic impacts.