San Ignacio Lagoon (Laguna San Ignacio) is a lagoon located Mulegé Municipality in the Mexican province of Baja California Sur, 59 kilometres (37 mi) from San Ignacio, Mexico and Highway 1. It is the winter sanctuary of the Eastern Pacific Gray Whales (Eschrichtius robustus).
San Ignacio Lagoon was originally discovered by whaling captain Jared Poole, brother-in-law to captain Charles Melville Scammon. The first whaling expedition to San Ignacio Lagoon occurred in 1860 led by Scammon and six whaling vessels. Although many whaling captains would not risk losing their ships to the treacherous sand bar shoals and narrow shallow water passage into the lagoon, enough bold whaling captains did and the beginning of the near extinction of the Pacific gray whale. The lagoon is now one of the primary destinations of the Gray Whale migration.
With a local community of less than one hundred inhabitants, the lagoon residents depend upon fishing and now whale watching as their primary means of support. The lagoon stretches sixteen miles into the desert and has a maximum width of five miles. The lagoon is divided into three sections. The upper lagoon is the shallowest part and is known as the birthing area where pregnant females travel to in order to bear their young. At the middle lagoon, you find mothers traveling with their newborns, getting them ready to join the majority of the whales at the lower lagoon. At the lower lagoon, you find the majority of the cetaceans and this is where most of the social behavior occurs. Here, males and females congregate looking for mates. In addition, the newborn calves with their mothers travel the length of the lower lagoon preparing themselves for the long journey north to their summer feeding grounds in the Arctic.
In 1988 Mexico established the El Vizcaíno Biosphere Reserve to include San Ignacio Lagoon, which is Latin America’s largest wildlife sanctuary. Not only is San Ignacio lagoon a gray whale sanctuary, but it is the last and only undeveloped nursery and breeding ground in the world of the Pacific Gray Whale. San Ignacio lagoon is also the critical habitat for the near extinct Berrendo or prong-horned antelope and an important feeding habitat for four of the worlds seven species of sea turtles: leatherbacks, hawksbills, green turtles and Olive Ridleys (all endangered). In 1993 the United Nations declared San Ignacio lagoon a World Heritage site because of its importance to the world community.