The grunion run is on again, and Saturday night may be one of the month’s best opportunities to witness the slithery, silvery, moonlit Southern California phenomenon.
Grunion are among the few fish to spawn completely out of water. They do it by the thousands, and they do it only in Southern California. According to the California Fish and Game Department, the grunion are likely to spawn Saturday night (Sunday morning) from 12:35 a.m. to 2:35 a.m.
Witnessing thousands of the small silvery fish glittering in the moonlight as the waves come and go along the shoreline can be quite a sight.
“It’s a pretty remarkable process,” said Melissa Studer, project director for Gunion.org, a Pepperdine University group of scientists, environmentalists and community members who monitor the grunion and educate the community about them. “They are pretty important culturally to us because this doesn’t happen anywhere else in the world, and it’s a very unique experience.”
The grunion spawn during the highest tide of the month from as early as March and as late as August, but April through June tends to be their most active period. When they spawn, the female fish will wash ashore on the high tide, wriggle a few inches into the sand, tail first, leaving her head exposed. She will lay about 3,000 eggs a few inches deep in the sand, and then the male fish will wrap around the female fish to fertilize the eggs. Roughly 10 to 14 days later, the eggs will hatch, allowing the next generation to swim off with the tide. The grunion spawn at age 1 and have a life span that ranges from two to four years.
It is impossible to predict exactly where and when they will spawn. Typically, the best day to see them is a few nights after the full or new moon.
There is a two-hour window after high tide to see the grunion run. To see them, be patient and look for the shorebirds—they always know where to find the grunion.
The grunion play a big role in the ocean’s food chain, and observers will sometimes catch glimpses of small sharks and other predators during a run.
The grunion do prefer a sandy beach with flat slopes and quiet conditions. They spawn on beaches from Baja up to Point Conception.
Grunion Run Tips
- Legally, you can use only your hands to capture the grunion.
- People over the age of 16 must have a license to catch grunion.
- Grunion cannot be captured in April or May.
- Be sure to wait until after the fish have spawned before capturing them.
- Only catch what you will use.
Violations can be reported to the California Department of Fish and Game at 1-888-DFG-CALTIP (1-888-334-2258).
Grunion.org asks for the public’s help in reporting grunion sightings for monitoring purposes.