Runnin’ with the GRUNION
BATHED IN MOONLIGHT, A FAT SEAL SPRAWLS on the sand and surveys the undulating blanket of silver and green that covers the shore at Long Beach. A strange slapping sound -- wet rubber against rubber -- fills the air. As far as the eye can see, the beach is slippery with grunion, jumpy little fish the size of ballpark franks, flopping around. An excellent late-night buffet.
For the last hour, grunion have been jumping out of the surf and pummeling the shore in a 30-second mating ritual that is unique in the animal kingdom. The seal, belly full of fish, isn’t impressed. It snaps at a nearby grunion and then slowly lowers its head as if to say “No mas. No mas.†It’s hard being a seal during the grunion spawning season. So many grunion. So little time.
A massing army
Earlier in the evening, before the seal went fishing for dinner, grunion were massing just offshore, like an invading army under the cover of darkness, thick snakes below the shadowy dark waves.
Grunion watchers gathered on the beach and waited patiently. But their timing was off. The kids got cranky, and the beer ran out. The evening grew chilly, marriages were tested and eventually everyone went home disappointed, with sand in their shoes and mud on their shorts. They had just been initiated into a Southern California ritual: the abortive grunion run.
When the run finally started two hours later, the only ones left to see it were a few beachcombers and one lazy seal. As usual, the grunion were laughing.
Grunion are as much a part of Southern California culture as surfboards and the Hollywood sign, but without the romance. Any newsletter, club or soccer team with the name “grunion†isn’t aiming for a shelf full of awards. Teenagers who’ve never seen the fish use them as alibis to stay out late. Frank Zappa penned a song for them, “The Beverly Hillbillies†devoted an entire episode to them, and still they get no respect.
But the hapless grunion is the only fish in the world that jumps out of the water onto the beach to spawn, which qualifies it as a bona fide international star in ichthyological circles. And it’s only found in our backyard -- coastal California and the Gulf of California in Baja.
All of this renders the scrappy grunion a fitting mascot for our sun-drenched do-it-now culture. In Southern California, where so many of us arrived from somewhere else, we can relate to this fish-out-of-water story.
It’s not surprising that after all these years of having grunion right under our noses, we think we know them. But although scientists are slowly piecing together some of the grunion puzzle -- they know, for example, that about 25 different parasites like to hang out on the diminutive fish -- they still haven’t answered the most fundamental questions about them. They don’t know, for example, where grunion go when they’re not spawning. When it comes to understanding the grunion population -- the grunion gestalt -- scientists are just getting started.
This much we do know: From March through September, after the highest tides associated with a new or full moon, grunion surf the tide until they land in clusters onshore to spawn.
The female tunnels tail first into the liquid wet sand, then lays as many as 3,000 bright pink eggs -- 18,000 over the entire season -- while the male wiggles his way to a female and deposits his milt around her. The milt, which contains as many as a million sperm, filters down her body into the sandy tunnel she’s built.
Males are capable of several trysts in one run. After spawning, the grunion work their way back to the breakers and return to the ocean. In a typical run, all will live to spawn another day.
Whoever coined the term “cold fish†never met a grunion.
Fish like no other
If the grunion had an agent, it would be Karen Martin, a professor of biology at Pepperdine University.
Pacing around her lab, Martin talks fast, words piling up, then spilling out as she pours salt water into a beaker of sand laced with grunion eggs. Within seconds, tiny grunion are darting around the beaker like sea monkeys.
Martin thrills to strange fish, like the climbing perch of India, which leaves the water to climb trees for no other reason than to watch the world go by.
“There’s something scientifically interesting about a fish that jumps out of water,†says Martin, who’s been studying grunion for almost 10 years.
She has embarked on the most ambitious longitudinal population study of grunion since the 1940s. With help from a number of institutions and hundreds of volunteers, she is gathering data that she hopes will shed light on the sustainability of the grunion population and the health of the beaches they spawn on.
As Southern California beaches are subjected to more and more foot traffic and pollutants, the grunion may be the canary in the coal mine.
Giacomo Bernardi, an associate professor of biology at UC Santa Cruz, is studying grunion from a different angle. Through genetic studies, he hopes to learn how and why Leuresthes tenuis and its sister species, L. sardina in Baja’s Gulf of California, evolved into separate populations.
Bernardi, who has a doctorate in molecular biology from the University of Paris and has studied grunion for about 10 years, retains his lovely French accent -- a fitting spokesman for the romance-minded grunion.
He theorizes that grunion originated in the northern Gulf of California, and its spawning behavior was an adaptation to long, flat tidal zones. Another theory about how the species’ unusual mating practices evolved is that fertilized eggs buried in sand are safer from predators than those floating in the ocean.
Two seas, two species
Bernardi hews to current thinking that sometime between 1.5 and 6 million years ago, geological movement created a shallow seaway between the inner and outer coasts on the northern end of the Baja peninsula that allowed grunion to pass between the Gulf of California and the ocean. Eventually that passageway closed, separating the populations and causing the species to branch off.
The chief difference between the two species is that Gulf of California grunion have smaller eggs and spawn in daylight.
Like Martin’s, Bernardi’s enthusiasm for grunion is infectious.
“It is a very cool fish,†he says, emphatically. “All over the world, whenever scientists talk about spawning, they talk about grunion. People who aren’t usually in close contact with fish get to see them. They are the ambassador of the fishes.â€
Scientists such as Martin and Bernardi are picking up where another scientist left off more than 50 years ago.
Except for a few scattered studies, grunion swam under the scientific community’s radar until 1947, when they caught the eye of Boyd W. Walker, a marine biologist at Scripps Institution of Oceanography in La Jolla and doctoral student at UCLA.
Walker studied the fish for more than three years for his doctoral thesis, charting their behavior and tying their cycle to the tides. He enlisted the help of his wife and scores of faculty members and their families to clip the fins of hundreds of fish so they could be tracked in subsequent spawning seasons.
Walker’s 1949 dissertation would become the bible of grunion research. “I reread his thesis regularly,†says Martin. “And I’m amazed at how much it holds up.â€
Grunion research got an assist in 2001, when a small group of San Diegans began to question the effects of beach grooming -- raking the sand with tractors -- on delicate grunion eggs. Concerned residents believed that grooming could kill grunion eggs, with long-term consequences on the population.
A study by Martin concluded that as long as beach grooming stayed above the highest tide mark, the grunion would be safe. But the grooming issue brought to light two key points: that careful beach management was key to grunion health, and that no one knew much about how Southern California’s grunion population was faring.
All of this led to the formation of the Grunion Greeter project, a network of volunteers who observe grunion runs and record data on spawning behavior and habitat. It is this data that Martin will use in her studies.
The project, which started in 2002, has grown from 200 to 500 volunteers and now extends all the way to Monterey. Volunteers attend grunion runs and record observations on time, duration and quantity of fish. The collaborative approach may already be paying off.
Last week a spotter discovered the fish on Crown State Beach in Alameda, which is on San Francisco Bay -- the first time grunion have been observed spawning in that area. “There are some interesting differences between the bay grunion and the coastal grunion,†says Martin. “They are clearly a different population and maybe even a distinct group.â€
More important, the grunion showed up when they were least expected. “It’s likely they’ve been there all along, but no one knew where to look,†says Martin. Again, the grunion are laughing.
The goal of it all
The next morning in Long Beach, long after the seal has returned to the water, the grunion are gone. Etched in the sand are telltale scratches, like hieroglyphics. Small tails and fins have left faint trails.
Underneath lie millions of grunion eggs, slowly turning from bright pink to orange, each slightly bigger than a grain of sand. Later, flies, sandworms, beetles and shorebirds will feed on them. The eggs will incubate in the sand for 10 days, then hatch and return to the ocean on the next high tide.
In two weeks the highest tide will bring another flotilla of fish that will jump from the water and anxiously hit the beach to mate, and another round of grunion seekers will attempt a late night rendezvous -- when the world is silent and mysterious -- to stare at the creatures in slack-jawed wonder.
Grunion love to disappoint us, but they also connect us, much like rooting for the same losing home team that every so often stuns us with a glorious win.
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Catch sight of the silver
What are your chances of seeing grunion? You can improve the odds by going with the pros at the Cabrillo Marine Aquarium at 3720 Stephen White Drive in San Pedro. The Meet the Grunion program includes a slide show about the elusive fish and a naturalist-guided stroll to the beach to see the real thing. The next programs are June 8 and 22, and July 8 and 22. Tickets cost $5 for adults; $1 for kids and seniors. Call (310) 548-7562 or go to www.cabrilloaq.org/spevents.html.
Next month, the grunion should show on beaches from Malibu to San Diego on:
June 8 10:25 p.m. to 12:25 a.m.
June 9 11 p.m. to 1 a.m.
June 10 11:40 p.m. to 1:40 a.m.
June 12 12:20 a.m. to 2:20 a.m.
June 23 10:40 p.m. to 12:40 a.m.
June 24 11:35 p.m. to 1:35 a.m.
June 26 12:30 a.m. to 2:30 a.m.
June 27 1:35 a.m. to 3:35 a.m.
Grunion fishing season opens Wednesday, with grunion seekers limited to using their hands to catch them (no buckets or nets). A fishing license is required for ages 16 and older. Go to www.grunion.org.
Janet Cromley can be reached at [email protected].
