Rose Atoll, part 2

by Kerry Grimshaw
photographs by Jean Kenyon

Exposed coralline algae at Rose Atoll

Our day began with a beautiful sunrise and light winds at Rose Atoll, which is one of the smallest atolls in the world and is diamond shaped. The outer reef slope around Rose is steep down to depths greater than 200 meters (~650 feet). The atoll also encompasses 2 small islets named Rose and Sand Islands. Perhaps the most outstanding feature of the atoll is the bright pink color of the exposed reef. The reef gets itís pink hue from the dominant crustose coralline algae Porolithon. This crustose coralline alage is one of the primary reef-building species at Rose Atoll.

Rose Atoll has a coral and fish community different from elsewhere in American Samoa. Currently the US Fish and Wildlife Service reports that there are 113 species of coral and about 270 fish species recorded at Rose. The atoll also supports the largest populations of giant clams, nesting seas turtles and rare reef fish species in the territory. In addition, humpback whales, pilot whales and various species of dolphin have been seen in the waters surrounding Rose Atoll.

Reefs dominated by coralline algae

The 2 islets are not without their own claims of importance. Rose Island is home to a grove of Pisonia trees on it, which is the only remaining Pisonia stands in Samoa. Rose and Sand Islands provide vital nesting habitat to the most important seabird colony in the region, including 12 federally protected migratory seabirds. Some of the birds that utilize Rose Atoll are the Red-footed Boobies, Greater Frigate birds, Lesser Frigate birds, Black Noddies, White Terns, Reef Herons and Red-tailed Tropic birds.

Since Rose Atoll is very remote and extremely unique due to its terrestrial and marine communities it provides an excellent place for scientific research. As such, our days spent at Rose Atoll are always a highlight of our cruise!