In ordinary times, the grunion at night form relatively small groups, but during the time of the grunion’s spawning the grunion form huge schools of extraordinary density. As the grunion, in their densely packed ranks, venture forth towards the shore the brown pelicans and seagulls that had mustered their own ranks in anticipation of just this event sprung from their ambush in the shoreside rocks to descend on the bright silvery huddle. The pelicans and gulls plunge into the sea, taking great mouthfuls of fish, but the grunion appear in such density that their number is hardly depleted. As the gulls and the pelicans continue their assault from above, the grunion face another threat from below as the totoaba strike from the depths. The totoaba, a species of particularly large croaker, lunge voraciously and the grunion form boils at the surface as they flee its eagerly grasping jaws. As the grunion near the shore, they halt just outside the surf zone at which point a few male grunion head for the shore alone to allow the surf to carry them in and across the wave tossed beach. These grunion are called scouts, and for good reason, for if they are interrupted in their expedition the runs often do not materialize. However, if the scouts do return unmolested, the grunion run begins in earnest and the grunion move together, allowing the waves to carry them inshore, then actively fighting against the wave as it returns to the sea so that the grunion may remain onshore to perform the actual act of reproduction and the at first incomprehensible ritual that precedes it.
|Grunion Spawning. Jeff Foott/Discovery Channel Images/Getty Images|
With the coming of the next full or new moon, the final chapter of this unique saga begins to unfold as the next spring tide washes over the now fully developed grunion eggs. The progeny of the previous spring tide’s grunion run feel the ocean water move in and over the restful cavity of damp sand in which they had been incubating and an instinct as primal as their parents’ comes over them. The larval grunion emerge from their eggs and between the spring tide eroding the cavity in which they had been given form and the onrush of water making the sand itself a more tractable medium for movement, the grunion reach the surface of the sand where the tide’s embrace carries them out to sea.
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