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Kure Atoll (28° 25' N - 178° 20' W)


Geography

Kure Atoll is the most remote of the Northwestern Hawaiian Islands (NWHI), and the northern-most coral atoll in the world. It lies close to what is called the Darwin Point, the latitude at which reef growth just equals reef destruction by various physical forces. It is 1,200 miles (2,222 km) northwestward of Honolulu and 56 miles (104 km) west of Midway Atoll. Kure is a small oval-shaped atoll with a land area of 0.86 km2 (213 acres) and reef areas to 100 m depth totaling 167 km2 (41,267 acres). The barrier reef is about 15 miles (28 km) in circumference and 6 miles (11 km) in greatest diameter. There is an opening on the southwest side through the reef to the shallow lagoon, but only small craft can enter. Along the south side of the lagoon are one small island and two sand banks. The somewhat crescent-shaped island, Green Island, is approximately one mile long by less than half a mile wide. It is located in the southeast corner of the lagoon.

Kure Atoll
Map of Kure Atoll (NOAA)

It is believed that Kure Atoll was discovered in 1825 by B. Morrell, Jr., the captain of the schooner Tartar. Over the years, many ships have crashed into Kure Atoll's fringing reefs. The U.S. Coast Guard operated a long-range navigation (LORAN) station there for many years.

Kure Atoll satellite image
The IKONOS satellite imagery of Kure Atoll (Photo: NOAA)
Green Island reaches a maximum height of 25 feet and is about 1.5 miles long and .5 mile wide
Green Island reaches a maximum height of 25 feet and is about 1.5 miles long and .5 mile wide (Photo: Space Imaging/ NOAA)

Terrestrial vegetation

Kure Atoll is bordered all around by sand dunes, which rise steeply from the waters edge to a height of eight to 20 ft above sea level. The dunes and most of the interior are covered with a dense growth of beach Scaevola, a branching shrub with large, glossy green leathery leaves, small white flowers, and small white fruit. This shrub reaches a height of five to six feet. There is a large open grassy area toward the eastern end of the island surrounded by Scaevola. Most of the other 13 species of the island's vascular plants are found here. The two other islets, lying close to the southern reef, between Green Island and the entrance into the lagoon, are sandy and usually devoid of vegetation.

Click here for a botanical inventory and annotated checklist of the plants of Kure Atoll: Botanical Inventory of Kure Atoll Reference: Starr, F., K. Martz, and Lloyd Loope. 2001. Botanical Inventory of Kure Atoll. Report prepared for State Department of Land and Natural Resources, Honolulu, Hawai'i.

Birds

Green Island is a habitat and nesting area for hundreds of thousands of seabirds which include shearwaters, petrels, tropic birds, boobies, frigate birds, albatrosses, terns, and noddies. It is also a wintering area for a variety of migratory bird species from North America and Asia. Bird life is less abundant on Kure than on other islands of the NWHI.

Click here for a Checklist of the Birds of Hawaii - 2002

big-headed ant
The big-headed ant, Pheidole megacephala (Photo: Hirotami T. Imai and Masao Kubota, Japanese Ant Database Group)

Monk seals, turtles, and insects

Kure Atoll is an important pupping and resting area for Hawaiian monk seals. The monk seal population size at Kure is currently about 100-125 individuals. Sea turtles are common on the beaches. Thirty-five species of insects were identified in 1923 from specimens collected by the Tanager Expedition, which made a careful biological survey of the island. Unfortunately, an invasive species, the big-headed ant (Pheidole megacephala), has overrun the ecosystem on Green Island. The density sampling, recorded on average, 26,500 ants per square meter on the surface at the sample sites. To complicate matters, these alien ants feed on the nectar of another introduced insect, a scale, that is also very common on island. The scale breeds on an introduced plant, Verbesina encilioides, which has also overrun the island. As the plant continues to spread so does the scale population, which assists in the population explosion of big-headed ants.

Corals and other invertebrates

The reef habitats of Kure Atoll include outside reef slopes, wave-scoured spur and groove habitats, overhangs and holes, passes, carbonate platforms, patch reefs, coral rubble, and sand flats. Considering water temperatures and latitude, Kure Atoll hosts a surprising diversity and numbers of corals and other large invertebrates, particularly echinoderms, crustaceans, and mollusks.

Corals at Kure Atoll
Corals at Kure Atoll (Photo: Bishop Museum)

Twenty-seven species of stony corals have been documented at Kure Atoll. Northwestern Hawaiian Islands Coral Reef Assessment and Monitoring Program (NOWRAMP) recorded high live coral cover in some of the back reef and lagoon areas. Live coral cover is low on the ocean-facing reefs, but coralline algae are abundant. Large massive colonies of Porites compressa, Porites evermanni, Pavona duerdeni, and Montipora turgescens were found at many locations within the lagoon. The highest concentration of crown-of-thorns sea stars in the NWHI were recorded on the outer barrier reefs of the eastern rim. Common bottom invertebrates included rock-boring urchins, macroalgae, and branching Pocillopora. Many spiny lobsters (Panulirus marginatus) were also observed.

Fishes

The lagoon and near-shore reefs support large schools of fishes, including jacks, sharks, dolphins, goatfish, and chub, as well as non-schooling species such as dragon morays, knifejaws, masked angelfish, and the rare native grouper, Epinephelus quernus (hapu'upu'u). Adult and juvenile cleaner wrasses were in the lagoon in large numbers. The lagoon supported many juvenile fishes. Many rare fishes which have seldom been observed in the Main Hawaiian Islands have been recorded at Kure Atoll.

Marine debris

Diver examining the anchor of a wreck at Kure Atoll.
Diver examining the anchor of a wreck at Kure Atoll. (Photo: Van Tilburg)

A significant threat facing Kure Atoll is the accumulation of marine debris washing up on the beaches and reefs. The atoll lies in the path of a major ocean current which deposits tons of fishing nets and other debris, creating an entanglement hazard for monk seals, turtles, seabirds, fishes and lobsters. Approximately 2700 pounds (1,225 kg) of marine debris was removed from Kure in 2003, including 997 pounds (452 kg) removed from accumulation study areas that were cleaned of all marine debris just the year before.

Biological data report

Click here for a report of biological data on marine algae, benthic invertebrates, coral cover and species, a list of fishes and their relative abundance, and other data. Northwestern Hawaiian Islands/Kure Atoll Assessment and Monitoring ... Reference: Northwestern Hawaiian Islands/Kure Atoll Assessment and Monitoring Program. Final Report. March 2002. Grant Number NA070A0457. By William j. Walsh, Ryan Okano, Robert Nishimoto1, and Brent Carman.

Link to metadata and data held by CoRIS

Click on the following URL to locate metadata and data in the CoRIS holdings of Kure Atoll. When the query screen comes up enter "Kure Atol"l in the window and then click on "Search".
http://coris.noaa.gov/geoportal/

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