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Gardner Pinnacles (25° 01' N - 167° 59' W)


Geography

Rising out of the ocean are two small, steep, basalt outcroppings, named Gardner Pinnacles. They are all that remain of a former volcanic island. The highest point is 190 feet (58 m). The pinnacles are approximately 690 nautical miles (1,278 km) from Honolulu and 150 nautical miles (278 km) from Maro Reef.

This five acre area comprises the smallest land area of any of the Northwestern Hawaiian Islands (NWHI). Underwater shelves, however, extend outward from the pinnacles over an area of approximately 604,000 acres (2,446 km2), the most of any island or bank in the NWHI.

IKONOS Satellite image of Gardner Pinnacles
IKONOS Satellite image of Gardner Pinnacles (photo: NOAA)
Gardner Pinnacles map
Map of Gardner Pinnacles (Photo: NOAA)
Gardner Pinnacles abrupyly rise from the sea
Gardner Pinnacles abrupyly rise from the sea (Photo: J. McVey/NOAA)

Reef biology

The endemic Hawaiian limpet
Cellana sandwicensis, the endemic Hawaiian limpet (opihi), has been a popular food source in Hawaii for centuries.

Gardner Pinnacles’ rocky intertidal areas are known for their abundance of giant opihi, Cellana talcosa, the endemic Hawaiian limpet. The opihi has all but disappeared from the Main Hawaiian Islands and is also very rare in the NWHI. Twenty-seven documented species of stony coral are distributed throughout the Pinnacles' reef system, many more species than observed at the comparable basalt islands of Nihoa and Necker. Acropora table corals have been noted on the more sheltered leeward (western) side, while tube (Tubastraea, Balanophyllia), stony, and soft corals have been found throughout the reef system. Stony coral cover is poorly developed on the more shallow basalt slopes and flat pavements, probably due to strong abrasive wave action. Live coral cover ranges from 1 to 15 percent.

The orange cup coral
The orange cup coral, Tubastraea coccinea (Photo: Keoki, Yuko Stender)
The Hawaiian oval coral, Balanophyllia hawaiiensis
The Hawaiian oval coral, Balanophyllia hawaiiensis (photo: Keoki, Yuko Stender)

Gardner Pinnacles underwater shelves provide habitats for some of the highest recorded numbers of fish species in the NWHI. Also, many species of fishes found in the MHI, but not found at other NWHI areas, are found here.

Birds and plants

In general, Gardner Pinnacles has among the highest diversities of marine life in the entire NWHI. However, only a single species of plant, a purslane, clings to its rocky surface. Gardner Pinnacles is also home to seabirds, insects, spiders, and mites. Scientists have observed 19 species of seabirds, 12 of which breed on the steep cliffs, including the rare blue gray noddy. Other birds include terns, boobies, frigate birds, and two species of migratory shore birds, the ruddy turnstone (Arenaria interpres) and the golden plover (Pluvialis fulva).

Sea approach to Gardner Pinnacles. Bird guano covers the steep cliffs
Sea approach to Gardner Pinnacles. Bird guano covers the steep cliffs (Photo: NOAA)

Click here for a description of Gardner Pinnacles land vegetation from the S.S. Midway Expedition.

Reference: Starr, F. and K. Martz. 1999. S.S. Midway Expedition. Trip report prepared for U. S. Fish and Wildlife Service, Honolulu, Hawai'i.

Link to metadata and data held by CoRIS

Click on the following URL to locate metadata and data on Gardener Pinnacles held by CoRIS on Gardner Pinnacles. When the query screen comes up, type "Gardner pinnacles" in the window, and click on "Search".

http://coris.noaa.gov/geoportal/

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