 The islets are volcanic rocks, with only a thin layer of soil and moss.About 49 plant species, 107 bird species, and 93 insect species have been found to inhabit the islets, in addition to local marine life with 160 algal and 368 invertebrate species identified.Although between 1,100 and 1,200 litres of fresh water flow daily, desalinization plants have been installed on the islets for human consumption because existing spring water suffers from guano contamination.