Orange County Register

Grunion are spawning on California beaches in record numbers this year, appearing on Orange County shores by the thousands in silvery, wriggling masses.

Grunion trackers have been reporting huge runs up and down the coast, from the San Francisco Bay area to as far south as northern Mexico, said Julianne Steers, chief aquarist at the Ocean Institute in Dana Point.

The season starts in March or April, but is closed to collecting until June to ensure enough grunion can spawn without disturbance.

April runs are normally light, Steers said, but not this year.

“We were already having some pretty large runs,” she said. “We hadn’t seen it like that ever. The runs we’ve been seeing in June are very, very strong.”

Steers, who is also hatching grunion at the Institute for educational purposes, said the large number of grunion hit the top of the measurement scale, called the Walker scale, which goes from zero to five. In March and April, she said, researchers were getting W4s and W5s.

A W4 means thousands of fish; a W5 means so many fish that sand is not visible between them.

The most recent run was on the 9th and 10th of June, she said; the next will be around July 7-10. Among the best Orange County beaches, Steers said, are Salt Creek and Doheny State Beach.

Grunion, typically five to seven inches long, appear close to the new or full moon, with the runs usually hit their peak a night or two later, she said.

They take advantage of the highest of high tides to carry them up the beach, where they intentionally become stranded. Females dig themselves part way into the sand with their tails, while the males cluster around them to fertilize their eggs.

Then, with luck, the fish are carried back to sea by another wave. The eggs hatch a couple of weeks later when they’re hit by the next high tide.

Although collecting grunion, considered a delicacy by many, is legal this time of year, Steers still encourages grunion collectors to catch and release the fish.

The institute will hold an overnight, parent-child grunion event on July 10; anyone interested can register on the institute’s web site.

(Photos of grunion spawning and of grunion hatchlings courtesy Julianne Steers.)

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