Maps and Imagery
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.
Laysan Island: Detailed habitat shapefile (14 MB)
Laysan Island: Habitat cover shapefile (14 MB)
Click here to 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 1300 km WNW from Kaua'i and 900 kilometers ESE from Midway lies Laysan Island at longitude 171 degrees 45 minutes W and latitude 25 degrees 46 minutes N. Laysan Island is about 3.7 sq. km in size, which makes it the largest island in the NWHI. Laysan Island is surrounded by a vast 4,530 sq. km shallow-water coral reef ecosystem.
Laysan Island and its surrounding shallow-water coral reefs were formed approximately 17 million years ago when the underlying shield volcano and a portion of the associated coral reef bank were lifted above sea level.
Of all the Northwestern Hawaiian Islands, Laysan and Midway are the islands that have seen the most extensive alterations to their ecosystems as a result of human habitation. The ecology of Laysan has been extensively modified by humans. Although it was first discovered in 1828, it was not until the 1890s that Laysan began to suffer. Guano mining, the introduction of rabbits, and the harvesting of bird feathers and wings devastated the island and its fauna. By 1923, Laysan was essentially a wasteland.
After 1923, conditions on Laysan slowly improved. Laysan finches and ducks survived the destruction. Native plants slowly began to return. Visitors introduced other plants. In 1961, it is believed that, while establishing an astronomical monument, the military introduced sandbur, an invasive plant from Central America, to Laysan. By the end of the 1980s, sandbur had expanded considerably, but it does not provide a suitable habitat for the thousands of burrowing seabirds that nest on Laysan. Starting in 1991, the U.S. FWS began a sandbur eradication effort that successfully removed the weed from the island. However, constant vigilance is required, and every visitor is subject to a quarantine procedure. Before stepping foot on Laysan, every visitor must put on brand new clothes that have been held in a freezer for at least 48 hours. Special quarantine procedures exist for every island in the NWHI.
A hypersaline lake (0.7 sq. km) lies in the middle of Laysan Island. The island is home to an estimated 2 million birds, including thousands of boobies, frigatebirds, terns, shearwaters, and Laysan Ducks.