Under full moon, native fish arrive to dance on Bay shores in annual spawning ritual

Thousands of endemic grunion fish leapt onto Bay Area shores late Tuesday night for a seasonal mating ritual, a reminder that all animals are guided by the celestial clock.

In a midnight tour organized by the East Bay Regional Park District, a few dozen drowsy spectators arrived at the Robert W. Crown Memorial State Beach in Alameda at the peak of high tide with the moon at its fullest. The crowd stirred when waves hitting the beach began to wriggle with silver fish. The first few sightings of the sardine-sized species were followed by billows carrying hundreds more. The whole event was over in a couple of hours.