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Nihoa Island

Maps and Imagery

Nihoa Island IKONOS image Nihoa Island map
Small image of Nihoa Island Small IKONOS image of Nihoa Island
Nihoa Island bathymetry image Image of Nihoa Island habitat cover
Small bathymetry image of Nihoa Island Small image of Nihoa Island habitat cover
Nihoa Island detailed habitat image
Small image of Nihoa Island detailed habitat cover

Shapefiles

Click on the links below to download shapefiles which correspond to the French Frigate Shoals detailed habitat class and aggregated cover imagery. Each zipped shapefile consists of 6 separate files, with the same root name and .dbf, .prj, .sbn, .sbx, .shp, and .shx extensions.

Nihoa Island: Detailed habitat shapefile (7.6 MB)
Nihoa Island: Habitat cover shapefile (7.4 MB)

Download a .ZIP file which contains the Arc and PCI legend files (.avl and .rst extension) for the NWHI maps. When added to your Arc or PCI project, these files will cause the vector colors to match the geotiffs.

Description and History

Approximately 250 km WNW of Kaua'i and 1975 km ESE of Midway lies Nihoa Island at longitude 161 degrees 56 minutes W and latitude 23 degrees 03 minutes N. Nihoa is estimated to be 7.2 million years old. Erosion has left only about 0.6 sq. km of what was once a large island. The sheer cliffs of the island jut up to as high as 215 m.

Nihoa Island is the emergent portion of a large basaltic shelf that measures about 29 km long in a NE-SW direction 16 km wide. The depth of the shelf is typically between 34 and 66 m. In total, the shallow water shelf surrounding Nihoa covers an estimated 487 sq. km.

Nihoa is considered to be the best example of a nearly undisturbed coastal ecosystem in the entire Hawaiian archipelago. An estimated 500,000 birds of 17 species regularly breed on the island. The Nihoa Finch and the Nihoa Millerbird are found nowhere else on earth.

Sheila Conant, an ornithologist at the University of Hawai'i, began studies of the Nihoa Finch and the Laysan Finch in 1980. Her research revealed that food type and availability has influenced the evolution of the size and shape of the beaks of these birds. Dr. Conant's findings confirm that these birds can adapt rapidly (produce offspring with more appropriate beaks) to changes in food type and availability. For many years, similar research was conducted on the Galapagos Islands by Peter and Rosemary Grant of Princeton University.

The shallow-water coral reef communities found at Nihoa are the result of constant wave action. Throughout the year, Nihoa is constantly awash in powerful oceanic waves. Northeasterly Trade Wind-generated waves occur throughout the year with major impact from North Pacific swell during the winter. As a result, sand shifting on the shelf tends to inhibit coral settlement and growth.

Nihoa has a rich cultural heritage. The island has 88 Polynesian archaeological sites. Polynesians inhabited the island between 1000 and 1700 A.D. House sites, sweet potato terraces and religious sites still remain from these early settlers who had vanished from the island by the time Western ships arrived.