Pulau Mantanani consists of three islands namely Pulau Mantanani Besar, Pulau Mantanani Kecil and Pulau Lungisan, a small island just off the western shore of Pulau Mantanani Besar. Pulau Mantanani Besar is about 3 km across and 1.5 km at its widest point. Sandy, calcareous beaches surround the island, except on its northern side. Pulau Mantanani Kecil is a thin island 2.5 km by 0.7 km. The island is composed mostly of limestone bluffs and rocky shores, with little strand or kerangas vegetation (Sheldon, 1983). Pulau Lungisan is a 40 m high limestone stack covered with low trees and steep slopes close to Pulau Mantanani Besar.