It is that time of year again! The Grunion are here! If you do recall, last year we in California could not see the grunion last March and April, as we were not allowed anywhere near the water. Well, this year is different, and I, for one, am heading down this month to check them out in person. Down below, I present to you the 2021 grunion run schedule for Southern California.
What is a Grunion and How Do They Run?
The grunion (Leuresthes tenuis) are small silvery fish between 5 to 7 inches long that live about 3 to 4 years. Each year, between March and September, the grunion comes onto Southern California’s beaches to spawn during the Full and New Moons.
The female grunion catches a wave onto the beach and digs a hole while waiting for the males to touch her. Once touched, she will release her eggs, and the males will then release their milt (sperm) on her body, which then flows down onto the eggs.
The whole process happens rather quickly, and up to eight males may fertilize each female. An interesting fact is that the female grunion may be out of the water for over five minutes! Once the male is done, he will catch a wave back out into the ocean.
Each grunion run lasts for four consecutive days when the tide is at its highest and longest. The eggs are buried in the sand for two weeks until the next high tide arrives. When the larvae become agitated by the waves, they hatch and are taken back into the ocean by the tide.
April and May are peak spawning months, so only observation is allowed.