Blue Spring Manatees

Blue Spring, near Orange City, is the largest spring on the St. Johns River and the most important natural winter refuge for manatees on the St. Johns. Its water stays near 73 degrees year round, and when the river chills in winter, manatees crowd into the spring run to wait out the cold. Park staff count them each morning, and the count has grown from a few dozen when protection began to more than 900 on the coldest mornings in recent winters. Jacques Cousteau filmed the manatees at Blue Spring for his 1971 documentary The Forgotten Mermaids, which helped bring the animals' decline to national attention. The state bought the spring for a park the following year, and the spring run was closed to swimming in winter to give the manatees room. The spring vent sits at the head of a short run and drops into a cave that divers have explored to depths of more than 100 feet. In summer, once the manatees have left for the river, swimming and snorkeling reopen. Above the spring stands the Thursby House, built in 1872 by Louis Thursby, whose family ran a steamboat landing on the river and shipped oranges north. Individual manatees at Blue Spring are known by sight. Researchers identify each one from the pattern of scars left on its back by boat propellers, and the park has kept records on some of the same animals for decades.