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Meet the Grunion

From TideLines, Spring 2003
CREATURE FEATURE
What better excuse could you think of to sit on southern California’s sandy shore at night with some friends than to be at a “grunion run?” With excuses like this no wonder many people think that grunion runs are some kind of “snipe hunt” or our own version of the “submarine races!” But it does happen, as probably millions of people have witnessed, these small fish (to 7.5”) wash themselves up on the beach 3-4 nights after the new and full moon (syzygy tide conditions) from March through August.

Grunion (Leuresthes tenuis) is a member of the Silversides family of fish, which include the topsmelt and jacksmelt. Grunion range from San Francisco to Baja and are mostly found south of Point Conception. The unique thing about the grunion is not that its common name comes from a Spanish word that refers to a grunting sound they are supposed to make when spawning. The curious fact is that 1-3 hours after the high tide, female grunion and their male suitors wash up on the shore en masse while the females wriggle tail first into the sand laying some 1-3,000 eggs while the males encircle them depositing milt along her body fertilizing the eggs below the sand surface. In this protected pod the eggs develop for some 10 days when the next high tide agitates and hatches the baby grunion out. They will mature in one year or at 5” and will complete the cycle. Grunion live for 3-4 years and females may spawn 4-8 times per season.

Grunion may be eaten by many kinds of fish including halibut and croakers; probing shorebirds, sand worms, beetles and beach hoppers eat their eggs. Humans may only capture grunion with their bare hands (except during closed season-April and May) and grunion hunters over 16 must have a fishing license. Native Chumash and Tongva peoples feasted on Grunion runs but the most curious question that is not fully answered is how do the grunion know when it is time to do the “grunion dance,” is it the pull of the tides, the glow of the moon or something more subtle? Regardless of what draws you to the shore, this fish behavior is truly a southern California phenomenon and a longstanding part of CMA’s programs history, come join us as we celebrate this seaside ritual!

by Steve Vogel, Education Curator

From Cabrillo Marine Aquarium's FRIENDS publication

For CMA grunion run program information or more grunion information visit grunion.org, or link to the CA Department of Fish and Game website grunion page.

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This site was last updated on March 2, 2004.

Meet the Grunion

From TideLines, Spring 2003
CREATURE FEATURE

What better excuse could you think of to sit on southern California’s sandy shore at night with some friends than to be at a “grunion run?” With excuses like this no wonder many people think that grunion runs are some kind of “snipe hunt” or our own version of the “submarine races!” But it does happen, as probably millions of people have witnessed, these small fish (to 7.5”) wash themselves up on the beach 3-4 nights after the new and full moon (syzygy tide conditions) from March through August.

Grunion (Leuresthes tenuis) is a member of the Silversides family of fish, which include the topsmelt and jacksmelt. Grunion range from San Francisco to Baja and are mostly found south of Point Conception. The unique thing about the grunion is not that its common name comes from a Spanish word that refers to a grunting sound they are supposed to make when spawning. The curious fact is that 1-3 hours after the high tide, female grunion and their male suitors wash up on the shore en masse while the females wriggle tail first into the sand laying some 1-3,000 eggs while the males encircle them depositing milt along her body fertilizing the eggs below the sand surface. In this protected pod the eggs develop for some 10 days when the next high tide agitates and hatches the baby grunion out. They will mature in one year or at 5” and will complete the cycle. Grunion live for 3-4 years and females may spawn 4-8 times per season.

Grunion may be eaten by many kinds of fish including halibut and croakers; probing shorebirds, sand worms, beetles and beach hoppers eat their eggs. Humans may only capture grunion with their bare hands (except during closed season-April and May) and grunion hunters over 16 must have a fishing license. Native Chumash and Tongva peoples feasted on Grunion runs but the most curious question that is not fully answered is how do the grunion know when it is time to do the “grunion dance,” is it the pull of the tides, the glow of the moon or something more subtle? Regardless of what draws you to the shore, this fish behavior is truly a southern California phenomenon and a longstanding part of CMA’s programs history, come join us as we celebrate this seaside ritual!