submerged Sefton Reef (), almost reaching sea level, and to northwest, Yosemite Rock (). Podesta Island, once reported to lie farther to the west, is a phantom island. Climate Alejandro Selkirk has a subtropical climate, moderated by the cold Humboldt Current and the southeast trade winds. Temperatures range from to , with an annual mean of . Higher elevations are generally cooler. Average annual precipitation is , varying from to year to year. Rainfall is higher in the winter months, and varies with elevation and exposure; elevations above experience almost daily rainfall. Flora and fauna The Juan Fernández fur seal is known to have existed during the late 17th century on the island with the population of the seals on Alejandro Selkirk Island and Robinson Crusoe Island believed to be in excess of four million by the late 17th century. A census of 1797 estimated a population 2 – 3 million fur seals. The species was hunted to near extinction by the 19th century and was thought to be extinct for 100 years until 200 were found on the island in 1965. Since then, the population has grown steadily at 15% to 20% every year. The Masafuera rayadito is endemic to Alejandro Selkirk and one of the rarest South American birds with only 140 individuals left. The Alejandro Selkirk firecrown, Sephanoides fernandensis leyboldi, an endemic subspecies of the Juan Fernández firecrown, became extinct in 1908 due to feral goats and other introduced animals. The island has been recognised as an Important Bird Area (IBA) by BirdLife International because it supports populations of Stejneger's and Juan Fernandez petrels, as well as the Masafuera rayaditos. The flora on the island is in the Fernandezian Region Floristic Region, in the Antarctic Floristic Kingdom, but often also included within the Neotropical Kingdom. Endemic plant families include Lactoridaceae, with endemic plant genera also found. History Throughout much of its history, the island has been uninhabited. There was formerly a penal settlement along the middle of the east coast, at . About 20 buildings can be made out on detailed satellite images. The settlement was operative from 1909. It initially housed 190 criminals, while there were as many as 160 political prisoners from 1927 to 1930. The penal colony was abandoned in 1930. Recently, the island has seen regular settlement, with 57 people living on the island as of the 2012 census. In 1966 the Chilean