Hot spots exist in the crust of the earth. Above them, rock melts and bubbles up into volcanoes, creating igneous landforms. In the mid-Pacific, a hot spot created the Hawaiian Islands. Through geologic time, the islands have been moving slowly across the spot. As they do, new volcanoes add islands to the southwest of the chain. One is being born right now, Loihi, southeast of the big island of Hawaii. Meanwhile, old islands, created eons ago, are slowly sinking beneath the waves.
French Frigate shoals was once a subsiding volcanic island of the Hawaiian chain. It shows evidence of its ancient history in the coral of its sheltering reef, and in the steep 120- foot spike of La Perouse Pinnacle, at the focus of the crescent-shaped lagoon. This basalt spire and a shorter neighbor 350 feet northwest of it may be all that is left of a volcanic plug once built by glowing lava forced up from deep below.
As the volcanic island subsided and the ocean wore it away, coral organisms grew on its old rim, building up a reef and a chain of islets as the igneous rock they grew upon sank.
Only the pinnacles remain to show where a fiery volcano once built land in the middle of the ocean. The rest is flat sandy islets in a lagoon calmed by a sheltering coral reef. The islets curve inside 20 miles of reef. Named islands include Tern, Shark, Whale, Trig, Round, Gin, and Skate.
As the islands emerged, birds and marine mammals used them as shelter and stopover points. Alga grew on the organic matter in the lagoon. Fish came to feed, and predator fish came to feed upon them. The shoals are a sort of oasis in the deep sea.
Many rare and endangered animals shelter at French Frigate Shoals. Only a few researchers visit the atoll, and only caretakers stay. The Hawaiian Monk seal, second most endangered pinniped (mammal with flippers) in the world brings its offspring to the beaches, and the Honu, the green sea turtle, nests here in peace and privacy.
The islands and surrounding waters are preserved as part of the Hawaiian Islands National Wildlife Refuge, and protected by the Fish and Wildlife Service.
The Coral Reef
The reef contains the most coral species of any atoll in the refuge. There are 41 species of stony coral at French Frigate Shoal. The reef supports more than 600 species of invertebrates (animals without spines), according to the website of the Northwestern Hawaiian Islands Multi-Agency Education Project. There are sponges, coral worms, snails, sea urchins, and sea stars. Other reef denizens include crabs and lobsters, populations of which are slowly recovering from overfishing.
Algae
Countless varieties of red, green and brown algae live in the reefs, and especially near La Perouse Pinnacle. The guano (dung) of seabirds that live on La Perouse is believed to be responsible for this local abundance.
The Green Sea Turtle
The Honu, chelonia mydas, ancient Green Sea turtles, are a threatened species in Hawaii. For many years, they were killed much faster than they could reproduce. Fortunately, they are now protected at French Frigate Shoals. No bright lights confuse the nesting turtles when they come up on the beach to bury their eggs, and relatively few predators wait to attack the hatchlings.
About 90 percent of the surviving Hawaiian population of Green Sea turtles travels to the French Frigate Shoals to nest. Though the turtles are found throughout the Hawaiian Islands, the female generally swims to the shoals to lay her eggs.
There she comes ashore after dark, burrows a hole in the beach sand about two feet deep, and buries her eggs. In one season, a female might leave three or four clutches of eggs, each containing a hundred eggs or more. Then she may not mate again for two or three years.
Not all the eggs hatch. Of those that do, some tiny hatchlings may become prey of ghost crabs or other predators. Once the turtles reach the sea they may become tangled in fishing nets or line. Trash and pollution are also dangers for the turtles.
Fibropapilloma, however, is probably the biggest threat to these animals. A virus-caused fibrous tumor, it attacks turtles throughout Hawaii. However, recent research seems to show that turtles can recover from the disease, especially it they contract it after they are fully-grown. Healthy mature turtles are better able to resist the effects of the virus.
Adult green turtles generally eat a vegetarian diet of sea grass and algae, though the young eat both animal and vegetable matter. They mature by age 25, and begin to breed. Incidentally, they are not green. The name comes from their fat, once treasured as food. They are actually shades of brown, often beautifully mottled and variegated with touches of olive, darker brown and gray.
Monk Seals
Hawaiian Monk Seals also find refuge on the islands of French Frigate Shoals. They are the only tropical seal, and the only variety found only in the United States. They are critically endangered.
The Hawaiian name for the species is Ilio-holo-i-ka-uaua, and the scientific name is Monachus schauinslandi. Perhaps 1100 remain.
In the last 50 years, their population has fallen more than 60 percent, according to the Marine Conservation Biology Institute. They are solitary creatures, unlike most seals. When disturbed, mothers will sometimes abandon their pups.
Unfortunately, habitat loss has led to disturbance, while overfishing has led to declines in their food supplies. They live at sea, often feeding on invertebrates on the bottom, but come ashore to give birth and nurture their pups. Fortunately, the shoals offer shores where few humans walk.
Bird Life
Gooney birds stop at French Frigate Shoal. Their real name is the Laysan Albatross. Black-footed albatross stop there as well. The Blue-gray Noddy and the Brown Booby nest on La Perouse Pinnacle.
Terns of many sorts are found on the shoals, to the point that the island converted to an airfield during World War II is called Tern Island. The Great Frigate Bird visits the shoals, and so do other frigate birds, petrels, and shearwaters. A safe landing spot for many kinds of birds, it should help them to survive in a changing world. The Tern Island station monitors bird populations year round.
The French Frigate Shoals have a near perfect climate. The temperature seldom rises to the nineties by day or falls below the fifties at night. The trade winds blow, and the night sky dazzles, the stars undimmed by light pollution. Fortunately, the atoll is located far from civilization, and remains too dull and isolated to attract development. In any case, the refuge is closed to visitors, except by special use permit, and reserved for its residents alone.
