[3] The sediment in the lagoon and surrounding the atoll is mostly coarse sand, much of which originates from the corals and mollusc shells.

An estimated 143,000 birds use the atoll, mainly masked booby (Sula dactylatra), brown booby (Sula leucogaster), brown noddy (Anous stolidus), black noddy (Anous minutus) and sooty tern (Onychoprion fuscatus).

[2] The reserve has been designated an Important Bird Area (IBA) by BirdLife International because it supports significant seabird colonies.

[5] Protected species include the loggerhead sea turtle (Caretta caretta), hawksbill sea turtle (Eretmochelys imbricata), green sea turtle (Chelonia mydas), red-billed tropicbird (Phaethon aethereus), white-tailed tropicbird (Phaethon lepturus), the crabs Johngarthia lagostoma and Percnon gibbesi, the starfish Echinaster (Othilia) guyanensis, lemon shark (Negaprion brevirostris), and the corals Millepora alcicornis (sea ginger) and Phyllogorgia dilatata.

It was created on 5 June 1979 and is administered by the Chico Mendes Institute for Biodiversity Conservation.