French Frigate Shoals

French Frigate Shoals

French Frigate Shoals is an atoll consisting of a large, crescent-shaped reef surrounding numerous small, sandy islets. While the land area is only 1/4-square kilometer, the total coral reef area of the shoals is over 744 square kilometers.

 

French Frigate Shoals is an atoll consisting of a large, crescent-shaped reef surrounding numerous small, sandy islets. While the land area is only 1/4-square kilometer, the total coral reef area of the shoals is over 744 square kilometers.

French Frigate Shoals is a classic atoll, formed on top of a volcano now submerged after millions of years of erosion, and surrounded by a well-developed coral reef. In the center of the atoll is a unique rock formation, a steep-sided basalt pinnacle that juts out of the water and is the last remnant of the original volcano. In 1786, two French ships under the command of Compte de La Pérouse, making one of the first visits to FFS by Westerners, discovered the rock and named it “La Pérouse Pinnacle” after their captain.

The shoals are important historically because they were used by the military during World War II. Tern Island, a part of the atoll, was formed into a runway to serve as a refueling stop for planes en route to Midway. The original seawall and building structures remain. The island is inhabited during summer months by the National Oceanic and Atmospheric Administration (NOAA) National Marine Fisheries Service (NMFS) Hawaiian monk seal and turtle camps. The U.S. Fish & Wildlife Service regularly monitors the island with periodic trips throughout the year. 

French Frigate Shoals has one of the most significant reef systems in the Northwestern Hawaiian Islands. The reef supports the greatest variety of coral species including the acropora table coral, finger coral, and stony coral. There are also over 600 species of invertebrates such as sponges, coral worms, snails, lobster, crabs, shrimp clams, oysters, sea urchins, and sea stars. Many of these invertebrates are endemic (found only there) to the shoals. There are over 150 species of algae living among the reefs. They include red, green and brown algae. Other marine life are the large invertebrates such as echinoderms, crustaceans, and mollusks. One area of the reef consists almost entirely of bivalve clams. The outer reef waters support gray reef sharks, butterfly fish, and large schools of jacks and groupers.

French Frigate Shoals nutures plenty of charismatic megafauna -- the green turtles and Hawaiian monk seals. Over 90% of the Hawaiian population of threatened green turtles travel to the FFS for safe nesting. Satellite tagging of these turtles has indicated that most of them migrate to the main Hawaiian Islands to feed and then return to breed at French Frigate Shoals, while some turtles travel northwest to feed and others have traveled as far south as Johnston Atoll. The many small islets of FFS also attract the largest number of endangered Hawaiian monk seals in the NWHI. It is “their” place of refuge.