"Really, any sandy beach is good," said Karen Martin, a biology professor at Pepperdine University. "You can find them in an area with good waves — the surfer's beaches."
The fish breed March through August during full moons when the tide is highest. They don't migrate and are only found off our coast, Martin said.
Given that these fish are trying to do the deed and are notoriously shy to an audience, experts suggest keeping your distance.
"If you leave them alone, you'll see a better run," she said.
Usually the second hour of a two-hour run is best, according to Martin's website, grunion.org. A few grunions will venture out at the beginning as scouts. If they see a bunch of voyeurs waiting for the action with flashlights or cameras, they'll take a rain check on the late-night rendezvous, she said.
The public is permitted to catch the grunions when they come ashore, but they have to use their bare hands. No tools, Martin emphasized.
"You got to give them a fighting chance," she said. "We encourage catch and release. The gear is definitely a problem."
A grunion is usually between 5 and 6 inches long. The females can lay between 1,600 and 3,600 eggs during one spawning run. They can do up to six spawnings a year, according to grunion.org.
City officials suggest flat, sandy areas along Newport Beach's coast like the area between the Santa Ana River mouth and the Newport Pier are good for seeing the grunion run.
Grunion Run Times
9:45 to 11:45 p.m. Tuesday
10:15 p.m. to 12:15 a.m. Wednesday
10:45 p.m. to 12:45 a.m. Thursday