Tuesday, April 15, 2008

When the Grunion Run

In the darkness of a new moon, a dozen black-crowned night herons landed on a San Pedro beach and stood like sentinels facing the open ocean.

"That's a good sign," whispered marine biology researcher Jenn Corpuz, 26. "The herons know there is something coming."

Suddenly, the surf shimmered with flashes of silver, and a few small, slender fish wriggled on shore, as if to size up the situation. Then thousands of fish began riding in on the swells and piling up on the beach in writhing clots. "Grunion!" she said. "Turn on your flashlights, everybody!"

About 400 onlookers dashed to the shore to witness the reproductive mayhem of Leuresthes tenuis, the iconic Southern California fish that leaves its briny realm to mate on the sand.

They also were watching the launch of a scientific attempt to establish the world's first sustainable captive population of grunion -- a lofty goal for California marine aquariums. A half-dozen researchers and volunteers in white lab coats and cutoffs waded into the surf with plastic buckets, collecting as many as possible, then gently coaxing eggs and sperm into specimen vials before setting them free.

For several hours, the tiny strip of intensely urbanized beach next to one of the world's busiest ports was a landing zone for wave after wave of the 6-inch night-time spawners: vibrant, vulnerable and acutely aware they had little time to complete their urgent business.

Thousands of grunion eggs collected by volunteers at the Cabrillo Marine Aquarium.

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