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French Frigate Shoals: Maps and Imagery
View a full-resolution version (224 KB).
French Frigate Shoals map:
French
Frigate Shoals IKONOS image:
View the 13m-resolution version (1,107 KB).
Download the 8m-resolution version (1,973 KB zip file).
French
Frigate Shoals bathymetry image:
View the 13m-resolution version (1,073 KB) with depth scale.
Download the 4-meter resolution geotiff (16,340 KB zip file) . See the Digital number (DN) to Classification matchup for NWHI bathymetry files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
Image of French Frigate Shoals habitat cover:
View the 13m-resolution version (2,107 KB) with legend.
download the 4-meter resolution geotiff (3,889 KB zip file). See the Digital number (DN) to Classification matchup for NWHI habitat cover files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
French
Frigate Shoals detailed habitat image:
View the 13m-resolution version (1,738 KB) with legend.
Download the 4-meter resolution geotiff (4,638 KB zip file). See the Digital number (DN) to Classification matchup for NWHI detailed classification files.
See the legend PDF to view the colorbars for the depth scales and the legends for habitat cover and detailed class.
French Frigate Shoals: 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.
French Frigate Shoals: Detailed habitat shapefile (137 MB)
French Frigate Shoals: Habitat cover shapefile (113 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.
French Frigate Shoals: Description and History
Approximately 1500 km ESE of Midway Atoll and 700 km WNW of Kaua'i lies French Frigate Shoals at longitude 166 degrees 10 minutes W and latitude 23 degrees 45 minutes N. French Frigate Shoals was formed approximately 13.8 million years ago as the Pacific Plate crossed over a "hotspot" in the earth's mantle. The Pacific Plate continues to move WNW at about 9 cm each year.
French Frigate Shoals appears to be the remnant portion of an approximately 27 km-long crescent-shaped atoll. This atoll protects a 727 sq.-km shallow lagoon that is from 2 to 10 km wide. La Perouse Pinnacle, located at the southwest corner of the lagoon, is the major visual landmark in the area at French Frigate Shoals. La Perouse Pinnacle is the dense rock remnant of the central lava tube that formed the volcano. Everything else surrounding this central tube has been eroded. Numerous sand islets dot the lagoon area of French Frigate Shoals. Waves and currents constantly change the size and shape of these sandy islets.
French Frigate Shoals is the most important breeding and nesting area for the Hawaiian green sea turtle in the entire Hawaiian archipelago. As much as 80 percent of all green sea turtles in the entire Hawaiian archipelago return to French Frigate Shoals to nest and breed. The numerous shoals and sand bars offer perfect habitat in which these ancient creatures can reproduce. French Frigate Shoals also is home to millions of birds. On Tern Island alone, an estimated 1.5 million Sooty Terns nest and breed.
French Frigate Shoals presents a contrast in seabed habitats. Vast areas of many square kilometers are devoid of reef coral development, while other areas are among the richest reefs observed in the Hawaiian archepelago. Sand, rubble, uncolonized hardbottom and crustose coralline algae dominate the lagoon and the windward reef. It appears that severe North Pacific Swells and NW Trade Wind Swells suppress reef coral development in major areas of the atoll. Large amounts of sand constantly move with shift ing wave patterns and currents along the lagoon floor, periodically burying and uncovering large areas. As a result, the sand islands constantly change size and shape. In addition, the NE trade winds prevail throughout the year and drive lagoon circulation. The average wind velocity is 12 knots.