Located in the Southwest Islands of Palau, Helen Reef is a large enclosed atoll with extensive reef flats, a large channel complex, and a small island that is an important sea turtle nesting site and an over-flight refuge and nesting site for several species of seabirds. At 163 square kilometers in extent, Helen Reef is roughly two-thirds the size of Palau’s largest island, Babeldaob. The Helen Reef ecosystem is one of the Pacific’s most notable atolls in terms of its area, ecological integrity, abundance of marine biomass, and biological diversity.
Remote from dense human settlement and land use, Helen Reef is relatively intact compared to similar biodiverse reef systems in Indonesia and the Philippines. However, a long history of exploitation has resulted in population declines of some of Helen Reef’s economically valuable species.
Helen Reef’s proximity to Indo-Pacific centers of coral and fish diversity has resulted in high species richness and unique fauna compositions relative to the rest of Micronesia.
Helen Reef is home to a very high number of reef fish species (530 species [Donaldson and Meyers, in preparation]), soft coral (43 species recorded [Birkeland et al., in preparation]), and the highest diversity recorded of hard corals of any Pacific atoll (282 species [C. Birkeland et al., in preparation]). Other significant living resources include aggregations of important reef fish species including groupers and snappers. Helen Reef is home to populations of giant clam, large economically valuable reef fish, marine mammals, and near-shore pelagic fish (Maragos and Cook, 1995).
Helen Island supports nesting populations of green turtles (Chelonia mydas) and exhibits some of the highest densities of foraging Green and Hawksbill sea turtles (Eretmochelys imbricata) in all of Palau (Geermans 1993; Birkeland et al., in preparation; Guilbeaux, interview; Idechong, interview). Helen Atoll is known to support some of the largest nesting sea bird colonies remaining in Mirconesia and nearby Southeast Asia (Keppler 1993), including Brown-footed boobies (Sula leucogaster), Red-footed boobies (Sula sula), the Great and Lesser frigate birds (Gregata minor and Fregata ariel), Great-crested terns (Sterna bergii), Black-naped terns (Sterna sumatrana), Sooty terns (Sterna fuscata), Black noddys (Anous stolidus), and White terns (Gygis alba). The rare population of coastal nesting Great-crested terns at Helen is thought to be one of the largest colonies remaining in the entire Pacific Ocean (King, et al. 1980; Keppler 1993).
Helen Reef is traditionally owned by the Hatohobei community which is represented by Hatohobei state. Of the 16 states, Hatohobei is one of Palau’s smallest with a population of approximately 200 people. They call themselves Tobians and over the years the Tobian people have left Hatohobei Island and Helen Reef to look for more economically sustainable ways of living on the main islands of Palau. Today, the Hatohobei southwest islands are a place for many Hatohobeians to visit, but not to live, and has changed the nature of their society and the character of marine resource use in the Southwest Islands.