Tuesday July 5, 2022
The Guardian —
On certain nights on a quiet California beach, thousands of small, silvery fish gather in the moonlight to perform a unique mating ritual.
Known as the “grunion run”, the spectacle is one of the lesser known natural wonders of the US west coast. Grunion are a rare fish species that come ashore to spawn, and during the months of April to August they cover beaches from Baja California to Santa Barbara like a glittering carpet, wriggling in the sand to lay and fertilize eggs just after the highest tide of a full or new moon.
The grunion run has fascinated scientists and locals alike for decades. But its future could be imperiled by the climate crisis – including warmer land and water temperatures and increasingly acidic oceans – as well as human activities such as fishing. Experts wonder how much time is left to unravel the mysteries that still remain about the grunion’s life.
On a recent night near Topanga, the beach was silent save for the rhythmic crash of waves and the dull roar of cars whizzing down the Pacific Coast Highway. Under a dark sky with the big dipper just beginning to peek out, Pepperdine University biologist Karen Martin and her students stood ready and waiting.