Weather Watch

When to catch a grunion on the Central Coast

A hunter shows off a grunion that was caught at Cabrillo Beach in San Pedro in 2009. The fish are well-known for their interesting spawning behavior.
A hunter shows off a grunion that was caught at Cabrillo Beach in San Pedro in 2009. The fish are well-known for their interesting spawning behavior.

Over the past few months, I received quite a few emails asking about grunion runs. Well, one of the first jobs I had while living in San Luis Obispo was to perform grunion run surveys in the middle of the night for the Port San Luis Harbor District.  

At the time, I doubted that I would ever see these silvery, turquoise fish about 5 to 7 inches long. After two nights of watching for these phantom creatures, I thought it was a bit of a snipe hunt.   

On the third evening immediately after high tide, I noticed the sound of them flopping on the beach after each successive wave break. Old Port Beach came alive that night with hundreds of California grunion. A marauding ban of local raccoons took full advantage of this rare bounty. If you happen to visit a sandy beach along the Central Coast at night after a full or new moon and immediately after high tide, you may see these unusual fish. It’s one of those natural spectacles that you’re unlikely to ever forget.

Like sea turtles, California grunion come ashore at night in the open air to lay their eggs near the high water mark. Spawning generally occurs during the spring and summer, peaking in May and June. These fish only spawn three or four nights after each full or new moon, and only for a few hours after high tide. 

Female fish swim on the beach with one or more males following closely behind. The females dig a nest into the wet sand, vertically, with their eyes directed toward the skies.

They can lay between 1,000 and 4,000 eggs about 3 to 4 inches beneath the sand, as the males fertilize the eggs. Nearly two weeks later when the spring tides return, the eggs hatch, completing a remarkable life cycle. Evidently, the young fish need the wave action to break loose from their shells.

Nobody knows how the grunion can so precisely time the tidal cycle. These fish seem to spend most of their life near the coast in about 15 to 60 feet of water and can live up to four years. John Steinbeck of Tenera Environmental told me that he has found grunion as far north as San Francisco, but they are most abundant from Morro Bay southward. It’s interesting to note that grunion found in the Gulf of California spawn during daylight. 

The grunion season is closed through May, but you can observe them. The next expected grunion run along the Central Coast starts on the night of May 4, right after high tide at 10:44 p.m. for about a two-hour period. The second hour is usually better. The next run will occur at 11:17 p.m. May 5, with another run at 11:53 p.m. May 6. The last run is forecast during the early-morning hours of May 8, at 12:36 a.m. 

The next run when you can actually take fish will occur June 2 right after high tide at 10:17 p.m. for about a two-hour period. The following run will occur at 10:55 p.m. June 3, with another run at 11:36 p.m. June 4. The last run of the period is forecast during the early-morning hours of June 6, at 12:22 a.m.

The best runs normally occur on the second and third nights of the four-night period. But please remember, the times listed are only predicted grunion run times. They might not always run during those times, because they can be rare events.

Watching old and young alike trying to catch grunion on a foggy night by hand is always enjoyable; however, they’re no match for the local raccoons at capturing these slippery fish.

Please remember, you can only catch grunion by hand, and you also need a valid California state fishing license if you are older than 16. There is no bag limit, but take only the fish you can use; it is unlawful and unethical to waste fish.