Shallow coral reefs thrive around the perimeter of Wake Island.

Fish populations are abundant and support at least 323 species, including large populations of the Napoleon wrasse (Chelinus), sharks of several species, and large schools of the Bumphead parrotfish (Bolbometapon), all of which are globally depleted. Beyond the shallow reefs, the outer reef slope descends sharply to great depths.

Baker, Howland, and Jarvis Islands were first formed as fringing reefs around islands formed by Cretaceous-era volcanoes (approximately 120-75 million years ago). As the volcanoes subsided, the coral reefs grew upward, maintaining proximity to the sea surface. These low coral islands consist of coral rock, shells, and sand that support trees, shrubs, and grasses adapted to the arid climate at the equator.

All three islands are surrounded by shallow coral reefs to depths of 100 meters, below which the reef slope descends steeply to great depths. Deep coral forests occur below photic zones (the depth of the water that is exposed to sufficient sunlight for photosynthesis) of all three islands at depths below 200 meters, especially at Jarvis where surveys have revealed living colonies of precious and ancient gold coral up to 5,000 years old.

The waters surrounding Baker, Howland, and Jarvis Islands have fish biomass double that of the Papahânaumokuâkea Marine National Monument, and 16 times that of the main Hawaiian Islands, due to the Equatorial Undercurrent that moves from west to east along the equator, creating localized nutrient-rich upwellings in shallows next to the islands. These are three of only six islands in the entire Pacific Ocean where this phenomenon is possible.

These islands are high in coral cover and biodiversity and are predator-dominated systems. Their biomass of top predators exceeds that of the Great Barrier Reef or Kenyan Marine Protected Areas.

The islands now host about a dozen nesting bird species including several nesting and migratory bird species that are of conservation significance. Jarvis alone has nearly 3 million pairs of Sooty Terns. There are about 300 fish species found off the islands. Giant clams (Tridacna), Napoleon wrasses, and Bumphead parrotfish are common, and sharks of many species are especially abundant at Jarvis and commonly larger there than elsewhere.

Hawksbill Photo By Caroline Rogers USGS NOAA

 Endangered hawksbill turtle and threatened green turtles forage in near shore waters. All three islands afford unique opportunities to conduct climate change research at the equator, far from population centers.

The coral skeletons there have recorded the earth's climatic history for many millions of years.

Johnston Atoll, the northernmost island in the island chain, is an ancient atoll and probably one of the oldest in the Pacific Ocean. Unlike most atolls, it does not have a surrounding barrier reef but has a semicircular emergent reef around the north and western margins of the island. Four major habitats characterize Johnston: low-lying islets consisting of the remains of corals and shells, shallow coral reefs to depths of 150 meters, deeper reefs to depths of 1,000 meters or more, and the slope of the ancient volcano on which the island rests.

Johnston is a genetic and larval stepping stone from the Remote Islands to the Hawaiian Islands for invertebrates, other reef fauna, corals, and dolphins.  Johnston supports thriving communities of Table corals (Acropora) and a total of 45 coral species, including a dozen species confined to the Hawaiian and northern Line Islands.

Monk Seal Twins Photo NOAA: The NOAA captive care and release research project seeks to aid recovery of the endangered Hawaiian monk seal. In May 2006, a rare pair of critically endangered Hawaiian monk seal twins—only the fourth set of twins ever documented and the first pair to survive past weaning—was brought to Honolulu from the Midway Atoll National Wildlife Refuge aboard a U.S. Coast Guard C-130 Hercules aircraft. Past observations indicated that twins have a high probability of mortality, and it will be a first if these twins survive and are successfully reintroduced back into the wild.

Some 300 species of reef fish are at Johnston, including the endemic Nahacky's pygmy angelfish. Many threatened, endangered, and depleted species thrive there, including the green turtle, hawksbill turtle, pearl oyster, giant clams, reef sharks, groupers, humphead wrasse, bumphead parrotfish, whales, and dolphins. Endangered Hawaiian Monk Seals occasionally visit the atoll. Deep diving submersible surveys have revealed that Johnston supports the deepest reef building corals (Leptoseris) on record and large populations of hydrozoan corals (Millepora, Distichopora, Staylaster).

Land areas support large populations of migratory shorebirds and resident seabird species, including populations of regional, national, or international significance: Wedge-tailed Shearwaters, Christmas Shearwaters, Red-tailed Tropicbirds, Brown Boobies, Great Frigatebirds, Gray-backed Terns, and White Terns.

Humpback Whale, Megaptera novaeangliae Photo NOAA

Approximately 200 threatened green turtles forage at Johnston. The surrounding waters are used by six depleted or endangered listed cetacean species: Sperm, Blue, Sei, Humpback, and North Pacific Right whales. Spinner dolphins are abundant, and endangered Humpback whales may calve there.

Palmyra Atoll is a classic Darwinian atoll that formed atop a sinking Cretaceous-era volcano. Kingman Reef formed in the same manner but is considered an atoll reef because it lacks permanent fast land areas or islands. Kingman Reef contains a sheltered lagoon that served as a way station for flying boats on Hawaii-to-American Samoa flights during the late 1930s. There are no terrestrial plants on the reef, which is frequently awash, but it does support abundant and diverse marine fauna and flora. Palmyra Atoll is managed by the United States Fish and Wildlife Service as a wildlife refuge. In 2001, the Secretary of the Interior established National Wildlife Refuges at Palmyra Atoll and Kingman Reef.

Palmyra Atoll and Kingman Reef are known to be among the most pristine coral reefs in the world, with a fully structured inverted food web. Kingman Reef is the most pristine of any reef under U.S. jurisdiction. They are ideal laboratories for assessing effects of climate change without the difficulty of filtering anthropogenic impacts. Both Palmyra Atoll and Kingman Reef support higher levels of coral and other cnidarian species diversity, 180-190 species,  than any other atoll or reef island in the central Pacific, twice as many as are found in Hawaii or Florida.

Palmyra atoll has one of the best remaining examples of Pisonia grandis forest found in the Pacific region. This forest type has been lost or severely degraded over much of its range due to increased human population and development. Fish species diversity at Palmyra, 418 species,  is higher than that of the other remote Pacific refuges, while that of Kingman, 297 species, is comparable to their populations.

Many threatened, endangered, and depleted species thrive there, including the green and hawksbill turtle, pearl oyster, giant clams (the highest concentration in the Pacific Remote Island Area), reef sharks, Coconut crabs, groupers, humphead and Napoleon wrasse, bumphead parrotfish, and dolphins. Significant numbers of threatened green turtles forage at both atolls, especially at Palmyra; endangered Hawksbill sea turtles forage at both atolls.

Large schools of rare Melon-headed whales reside off both atolls. A possibly new species of beaked whale was recently described from 2 specimens stranded at Palmyra and 1 at Christmas Island. Palmyra supports 11 nesting seabird species including the third-largest Red-footed Booby colony in the world. Large numbers of Bristle-thighed Curlews, a migratory shorebird of conservation significance, winter at Palmyra.

Rose Atoll Photo NOAA

The Rose Atoll Marine National Monument

In the Pacific Ocean approximately 130 nautical miles east-southeast of Pago Pago Harbor, American Samoa, lies Rose Atoll -- the easternmost Samoan island and the southernmost point of the United States. This small atoll, which includes the Rose Atoll National Wildlife Refuge with about 20 acres of land and 1,600 acres of lagoon, remains one of the most pristine atolls in the world. The lands, submerged lands, waters, and marine environment around Rose Atoll support a dynamic reef ecosystem that is home to a very diverse assemblage of terrestrial and marine species, many of which are threatened or endangered.

Few relatively undisturbed islands remain in the world and Rose Atoll is one of the last remaining refuges for the seabird and turtle species of the Central Pacific. Threatened Pisonia atoll forest trees are also found at Rose Atoll.

One of the most striking features of Rose Atoll is the pink hue of fringing reef caused by the dominance of coralline algae, which is the primary reef-building species. Though there are roughly 100 species of stony corals, the shallow reefs are dominated by crustose coralline algae, making them distinctive and quite different from those found at other Samoan islands.

The marine area provides isolated, unmolested nesting grounds for green and hawksbill turtles and has the largest number of nesting turtles in American Samoa. Its waters are frequented by numerous large predators: whitetip reef sharks, blacktip reef sharks, gray reef sharks, snappers, jacks, groupers, and barracudas.

Striped Dolpin Photo: NOAA

Species that have faced depletion elsewhere, some of which have declined worldwide by as much as 98 percent, are found in abundance at Rose Atoll, including giant clams, Maori wrasse, large parrotfishes, and blacktip, whitetip, and gray reef sharks. Humpback whales, pilot whales, and the porpoise genus Stenella have all been spotted at Rose Atoll. There are 272 species of reef fish, with seven species first described by scientists at Rose and dozens more new species discovered on the first deep water dive to 200 meters. Recent submersible dives around Rose Atoll have revealed abundant marine life, deep sea coral forests, and several new fish and invertebrate species.

Long-tailed Cuckoo: Shows two long-tailed cuckoos Eudynamys taitensis, the adult on a branch to the left, the chick on the ground receiving a worm from a grey warbler Gerygone igata perched on a branch above it. 1888, From Buller, Walter Lawry. A history of the birds of New Zealand. 2d. ed. Volume I. London, 1888. Plate 14, opp. p. 126, J. G. Keulemans delt. & lith. [Plate XIV, 1888].

Rose Atoll supports most of the seabird population of American Samoa, including 12 federally protected migratory seabirds, five species of federally protected shorebirds, and a migrant forest bird, the long-tailed cuckoo.

Rare species of nesting petrels, shearwaters, and terns are thriving at Rose Atoll and increasing in number. The atoll is known to Samoans, who have periodically visited over the past millennium, as "Nu'u O Manu" ("Village of seabirds"). It is believed that Polynesians have harvested at Rose Atoll for millennia and several species, such as the giant clam, were used for cultural celebrations and events.