Grunion Run Season in IB, Southern California Nears End

This weekend had one of the last full moons of the 2011 grunion spawning season, when the small fish beach themselves by the thousands to lay and fertilize their eggs on beaches throughout southern California and Baja California, between April and August.

Grunions, the 6-inch slender oversized sardines, nicknamed "the Silversides," may show off their blue, green and pink scales under the waning full moon July 15-18.

"The shimmer and shine of them all along the beach is beautiful," said Melissa Studer, Project Director of Grunion Greeters, who lead tours of grunion runs during the high season in the spring.  

Found nowhere else in the world, grunion runs have been spotted along the Pacific coast from a point about halfway down Baja, Mexico, and northward to Point Conception, Calif.

According to the California Department of Fish and Game they squirm and flop onto the beach within two hours after the waters of a full or new moon high tide begins to recede.

On Monday and early Tuesday morning they may be found from 11:45 p.m. to 1:45 a.m.

"Many people miss out by leaving too early," and the third and fourth nights after the full moon are the best, Studer said.

Male grunions lead the way, and are eventually followed by the females who come to dig and wiggle into the sand tail first.

Males wrap themselves around her to fertilizes the eggs with their seminal fluid or milt.

"What she's doing is laying her eggs" in a clutch, a golf ball-sized sack holding 1000-3000 bright pink salmon colored pouch.

Eggs then fertilized, mature a few inches below the surface over the next 10 days until agitation of the water on the next high tide induces hatching. Without water they will not hatch, and may wait two to three cycles until water washes over them, and back out to sea.

It is prohibited by California state law to dig traps to capture fish, but people with fishing licenses are allowed to take many fish as they can eat with their hands.

Contrary to common belief, grunions do not die after spawning, and males will spawn repeatedly, returning ashore multiple times within a two-hour run.

Returning to the ocean, the non-schooling fish lead singular lives, which makes them difficult to catch when not ashore.
 
Some surfers have reported that they have felt the grunions while waiting for a wave, according to Studer.

Boyd Walker of the Scripps Institution of Oceanography pioneered research on grunion spawning being on a lunar cycle, and designed the Walker Scale, which assesses the strength of the run.

Like the strength of a tornado, from the non-run W0, to the fairly rare W5, when little sand is visible between the fish. W2 and W3 runs are most common.

A strong run involves thousands, "everywhere you can see you can barely walk," Studer said. "We have been seeing more of them, and the runs are lasting longer" in the past few years, she said.

Along with increased runs, awareness and protection have increased, possibly due to the Beach Ecology Coalition (BEC).

The BEC has encouraged many counties to modify beach grooming activities to remove trash and kelp by raking with a tractor, a process that can harm maturing eggs under the sand.

Due to the impact of humans, the BEC recommends a catch and release policy, however grunions serve as great food for young birds and life forms further up the food chain.

While there are no keys to knowing where and when the grunions will run, there are a few indications a run will occur.

"The birds know they're coming before we do," Studer said.

Among nocturnal herons, as well as non-nocturnal birds like gulls and egrets, Studer said she once saw smooth hound sharks feasting on a run.

"It's pretty spectacular when you see it riding a wave in munching on some grunions."

Where's the best spot to find grunions?

There's no way to predict where they will show up, but the area must be sandy, flat, not steep and void of noise and disruptive activity.

Studer advises that lookers keep their lights steady, staying still and to avoid other vibrations. "It's best to be patient, watch for male scouts, stay where you are and wait," she said. 

Though grunions are not endangered, the California Department of Fish and Game prohibits fishing for grunions in April and May to maintain healthy population numbers.

Anyone taking grunions in open season is required to have a fishing license, must use bare hands, no gear and to only "take what you use."

For more information on training and volunteering as a Grunion Greeter from April to June next year, visit grunion.org, where anyone can submit observations of grunions online.