Isla San Pedro Mártir. 02/02/04; Sonora; 30,165 ha; 28°23'N 112°19'W. Reserva de la Biosfera. A small island of 127 ha off the coast of Sonora, regarded as one of the best preserved islands in the Gulf of California. The island is a favourite site for marine birds, as it hosts very large colonies of Blue-footed Boobies Sula nebouxii, Brown Boobies Sula leucogaster, Brown Pelican Pelecanus occidentalis and Red-billed Tropicbirds Phaethon aethereus. Two endemic lizards also inhabit the islands, Uta palmeri and Cnemidophorus martyris, and there is a colony of ca.2,500 California Sea Lions Zalophus californianus. The island is bordered by trenches more than 900 metres deep, where the waters of the northern and southern parts of the Gulf meet and generate an upwell. Cliffs and steep slopes dominate the island, which has very little vegetation apart from a small forest of Pachycereus pringlei and seasonal meadows of Wild Poppy Sphaeralcea hainesii. Its large guano deposits were exploited until 1978, when the island was declared a protected area. Presently there are only temporary fishing camps on the island, and ecotourism is still a minor activity. Ramsar site no. 1359. Most recent RIS information: 2004.