Grunion Run Schedule

The California grunion (Leuresthes tenuis) is a silverside, in the same family as jacksmelt and topsmelt. Its usual range runs from Point Conception to Point Abreojos in Baja California, and it lives close to shore, from the surf line down to about 60 feet; tagging has shown that it does not migrate. Most grunion on the beach are 5 to 6 inches long. They spawn from the end of their first year, and few live past three.

A run starts after a high tide on the nights that follow a full or new moon. Waves carry the fish as far up the slope as they reach. A female bends her body and works her tail down into the soft, wet sand until she is buried to the middle with her head out, then lays her eggs there. Up to eight males wrap around her and fertilize them. The whole act lasts about 30 seconds; the males slip back first and she follows on the next wave, though some fish lie stranded for several minutes. A female can spawn up to six times in a season, each time laying between 1,600 and 3,600 eggs.

The timing protects the eggs. Grunion spawn once the tide has started to fall, and on nights when each high tide is a little lower than the one before, so the following waves pile sand on top of the nest rather than scouring it out. The eggs end up 8 to 16 inches down in damp sand and are ready to hatch in about 10 days, when the next round of high tides reaches them. Churned loose by the surf, they hatch within minutes and the larvae are carried out to sea.

The season runs from March to August, with odd runs in February and September, and peaks between late March and early June. North of Point Conception grunion are scarce, but CDFW notes spawning reports from Monterey Bay and sightings of spawning inside San Francisco Bay. Our Monterey tide chart and San Francisco tide chart do not track grunion.

Grunion are not plentiful. CDFW names lost spawning beaches as the biggest threat, through erosion, harbor building and pollution, and asks watchers to leave spawning females and buried eggs alone. Volunteers in the Grunion Greeters program, started by Dr. Karen Martin of Pepperdine University, have counted runs on more than 50 California beaches for over 20 years, and their counts have been used to document recent changes in the population.

These are the California Department of Fish and Wildlife's rules for grunion, in short. Rules can change between seasons, so check the CDFW grunion page before you go.

• Anyone 16 or older needs a valid California sport fishing license, with the ocean enhancement stamp, to catch grunion.
• Watching a run needs no license. Touching or handling the fish in any way does, even if you let them all go.
• April, May and June are the closed season: no contact with grunion at all, though you may watch quietly.
• Grunion may be caught with bare hands only. No appliances of any kind, and no digging holes in the sand to trap them.
• The limit is 30 grunion per person per day.

California first closed April to June to grunion fishing in 1927, later shortened the closure to April and May for decades, and went back to three closed months in 2022, when research showed the population falling again. The 30-fish limit dates from the same change.