It’s that time of the year again—grunion run season! The only times of the year when you can see thousands of silver fish dancing in the sand along the California coast. Southern California also happens to be the only place you can see observe this surreal nocturnal mating ritual.
Every year, the small silvery fish wash onto Southern California beaches to fertilize their eggs so that they can make way for the next generation of baby grunion. During the spring and summer months, the moonlight casts a beautiful glow onto the breading grunions as they bury their eggs in the sand, waiting for the next wave to float them back to sea.
The female then arches her body and excavates the semi-fluid sand with her tail to create a nest, twisting her body and digging into the sand until she is half-buried with her head sticking up. She then deposits her eggs in the nest while a male curves around her to release milt. The milt flows down the female’s body until it reaches and fertilizes the eggs
This surreal activity is unique to SoCal shores, from San Diego to San Luis Obispo, and in Northern Baja, Mexico. The best time to observe a grunion run is straight after a San Diego to San Luis Obispo, and in Northern Baja, Mexico new moon phase from around 10 p.m. to 1 a.m.
The California grunion is usually used as bait for other fish, but the fishing season doesn’t start until June. When it arrives, beach-goers will be able to collect the fish but will need a proper fishing license and must be over the age of 16. You can find a list of the 2020 runs, here!
Also published on Medium.