Johnston Atoll is an unincorporated territory of the United States, Johnston Atoll is a National Wildlife Refuge and part of the Pacific Remote Islands Marine National Monument. It is closed to public entry, and limited access for management needs is only granted by Letter of Authorization from the United States Air Force and a Special Use Permit from the U.S. Fish and Wildlife Service.
About 300 species of fish have been recorded from the reefs and inshore waters of the atoll. It is also visited by green turtles and Hawaiian monk seals. The possibility of humpback whales using the waters as a breeding ground has been suggested, albeit in small numbers and with irregular occurrences so far. Many other cetaceans possibly migrate through the area, but the species being most notably confirmed is Cuvier's beaked whales.