The spawning season has arrived for silvery grunion fish to ride the waves ashore en masse to deposit their eggs in the sand. During the full and new moons when the tide is high, thousands of male and female fish cover the beach for less than a minute to spawn. Birch Aquarium will train volunteers to monitor the “running” grunions April 14 from 6:30 to 8 p.m. The volunteers are expected to observe the grunions throughout the season to collect data for a regional research project orchestrated by Pepperdine University. Birch Aquarium also invites the public to head to the beach to watch the grunion spawn, preceded by a short film about the fish, on April 16 from 9:30 to 11:30 p.m. The excursion costs $12 and fills up quickly, organizers said. Call (858) 822-5331 to RSVP, or e-mail [email protected]. “If you’ve never been on a grunion run, it’s nice to go on these programs because we can explain what you’re seeing,” said Charina Layman, public programs coordinator for Birch Aquarium. Grunions wait for high tides to send them far up on the beach to lay their eggs in dry sand. The females dig themselves into the ground to create a nest and deposit their eggs. The males wrap around the females and release milt, which flows down the female’s body to fertilize the eggs. The fish catch the next waves back, leaving the eggs on high, dry ground to hatch for 10 days. People are prohibited from taking the fish during April and May and must obtain a fishing license from June through August. For more information, visit http://arachnid.pepperdine.edu/grunion.