It’s the sort of romantic moment made for movies: the embrace of lovers on the beach under just the right midnight moon.
Only there are hundreds of them. And they are laying eggs. The grunion are running.
Every year between the months of March and August the silvery fish surf in on waves to lay their eggs in the sand. Grunion mating season is coming to a close with the last run expected between Aug. 29 and 30.
During the spawning season’s peak, grunion can be found up and down the Pacific coast from Imperial Beach near the Mexican border to as far north as San Francisco Bay, said Karen Martin, a professor of biology at Pepperdine University in Malibu.
“Grunion are about the strangest and most wonderful coastal fish there is,” Martin said.
“They have a very unique way of mating in that they use the sandy beaches to incubate their eggs.”
Martin heads Grunion.org, a group of scientists, environmental organizations, surfers and beach workers dedicated to studying the habits and habitats of the leuresthes tenuis, or beach-spawning grunion that measures 5 to 6 inches long. They are native only to the shores of Southern California.
There are other species of fish that come onto shore with the monthly high tide and mate for moments out of the water, but only grunion will keep their eggs out as well, Martin added. The sand protects the eggs for about nine days until they are ready to hatch.
Newport Beach is a great place to watch the grunion mating ritual, Martin said. But grunion are capricious and don’t always come ashore where and when predicted. The best place to catch them locally is between the Newport and Balboa piers, although observers could get lucky at any sandy beach during mating season when the tide is right.
The mating ritual may last only 30 seconds, but some fish get stranded on the beach for several minutes.
“People get all excited and forget they are looking at wildlife,” Martin said. “If you want to see them you have to be quiet and patient.” Too much noise will scare the fish off, and predators are always a concern, she added.
One of the grunion’s enemies is the giant squid, which has been abundant in Southern California this past spring and summer.
Martin’s group organizes volunteers called “grunion greeters” along the coast to monitor the fish and help in its conservation. For information about becoming a volunteer or to check on expected grunion runs, go to www.grunion.org.