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 ten 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; and 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 the Aquarium's programs history.  Come join us as we celebrate this seaside ritual!