California grunion are a species of marine fish found primarily along the coast of Southern California and Northern Baja California. They are justifiably famous for their unique spawning behavior. Grunion spawn completely out of the water and lay their eggs on many sandy beaches in California. Shortly after high tide, on specific nights, sections of these beaches sometimes are covered with thousands of grunion dancing about on the sand. The popularity of these grunion runs means that some nights there are more people lining the beaches than grunion in the run.
The eggs remain buried in the sand throughout incubation, fully out of the water for approximately two weeks. The larvae hatch when the eggs wash out by high waves during tides before the new and full moons. Grunion spawn at the age of one year, and live for two to four years. Because of their vulnerability during the spawning season, they are protected by a closed season. No taking of grunion is permitted during April and May. During other months, no gear is permitted,so collection may take place only with bare hands, and a fishing license is required.