Papahanaumokuakea and French Frigate Shoals

French Frigate Shoals (Kanemiloha‘i) is a crescent-shaped atoll formed by an eroded volcano, which has been submerged for millions of years. While the land area is only 67 acres, the total coral reef area of the shoals is over 232,000 acres. A steep-sided basalt pinnacle (La Pérouse Pinnacle) juts out of the water in the center of the atoll. Tern Island, which is part of the atoll, was formed into a runway to serve as a refueling stop for planes enroute to Midway during World War II. Six different species of terns have been recorded from Tern Island.

La Perouse supports a large number of seabirds, and the bird guano provides high nitrogen levels in the surrounding waters, which promote the growth of algae in the pinnacle’s intertidal zone, with more than 150 species of algae including red, green, and brown algae. The Shoals’ semi-enclosed lagoon gives protection from storms and waves, and provides many reef habitats. The reef supports the greatest variety of coral species in the NWHI with forty one species of stony corals, including table, finger, and lobe corals. It also supports more than 600 species of invertebrates such as sponges, coral worms, snails, lobsters, crabs, shrimps and clams, oysters, sea urchins, and sea stars.

The outer reef waters support gray reef sharks, butterfly fish, jacks, groupers, chevron butterflyfish, and endemic masked angelfish. The islets attract the largest breeding colony of the endangered Hawaiian Monk Seal in Papahanaumokuakea, while also serving as the breeding ground for 90% of threatened Green Sea Turtles in the Hawaiian Islands. Satellite tagging of these turtles indicates that most of them migrate to the Main Hawaiian Islands to feed and reach sexual maturity before returning to French Frigate Shoals to breed.