June 27, 2013

I was curious.  I had never seen a grunion run and learned this is the time of year to witness the event in southern California and a portion of  the Sea of Cortez near Baja California.  The Cabrillo Marine Aquarium in San Pedro, California, runs several programs every year to inform the public about the small, brave grunion — the only fish that can live 20 minutes on wet sand without water.

Grunion is the Spanish word for grunter.  On the second, third, and fourth nights after a full moon and a new moon during certain months of the year, those who are lucky enough to witness the event can see hundreds of squiggly little grunion making their way en masse from the water onto the beaches one to two hours after high tide.

The plucky six inch female quickly digs her way into the sand tail first.  She lays her eggs and is immediately surrounded by a male who releases milt that oozes down into the sand around the eggs and fertilizes them.  The female then spirals her way out of the sand and plops her way back to the sea.

The one and two year olds are the ones who spawn once every two weeks four to six times, depositing perhaps 18,000 eggs a season.  The parents long gone, the waves bring sand onto the beach, pushing the eggs safely further down in the sand where they can develop.  Three days after fertilization, the grunion forms.  In about 4 1/2 days, the heart starts to beat and blood carries food to the embryo from the yolk in the miniscule egg.  In 9 days, there is a baby grunion curled inside with two big eyes waiting.

Waiting for what?  The eggs must be agitated by wave action after 9 days for the infant grunion to burst forth and swim freely.  Their survival rate is not great, given all the humans, birds, raccoons, night herons, feral cats, worms, and sand predators waiting to eat them.  In fact, there are strict rules for humans who want to turn them into a deep-fried dinner.  In April and May, the law prohibits touching  the grunion.  In other months, humans can catch them only by hand, and require a fishing license.  Young children are allowed to catch them without a license.

After seeing a great film about their life story, and having the chance to agitate a small jar of eggs so that we could make them hatch, we trekked out to the beach bathed in the strong moonlight of a full moon at 10:30 p.m.  Everything was perfect — except that the grunion didn’t come on schedule.  My guess is that the shrieking, running, happy children carrying buckets to capture the grunion in made the grunion around there think better of coming up until most of the children had fallen asleep or left.

Our little group saw only one brave grunion dig itself into the sand, lay her eggs, squiggle out of the hole, and into the hands of an excited child.  I can’t say I wasn’t disappointed, but the whole adventure had been curiously satisfying.

 

 

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