Naturalists from the Birch Aquarium at Scripps Institution of Oceanography will lead tours of the annual grunion spawn on the beaches of La Jolla beginning Tuesday night and continuing through June.

On certain spring nights following high tides, hundreds of the small silvery fish ride the waves onto shore for this remarkable mating ritual, which happens only in Southern California.

While on the beach, female grunion bury themselves halfway in the sand to lay eggs, while males wrap themselves around the females to fertilize their eggs. Both catch a wave to return to sea.

Naturalists from the aquarium will serve as guides, beginning with an interactive presentation on grunion, and followed by a beach exploration by moonlight to witness the grunion run, nature willing.

Participants must be 6 years of age or older and bring a flashlight and warm jacket. The cost is $16 per person ($14 for acquarium members). Reservations are required by calling 858-534-7336 or reserving online.

The 2014 tour schedule for expected grunion runs is:

• Tuesday, April 1: 11 p.m. – 1 a.m.
• Thursday, April 17: 11 p.m. – 1 a.m.
• Friday, May 16: 10:30 p.m. – 12:30 a.m.
• Saturday, May 17: 11 p.m. – 1 a.m.
• Friday, May 30: 10:30 p.m. – 12:30 a.m.
• Saturday, May 31: 11 p.m. – 1 a.m.
• Saturday, June 14: 10:30 p.m. – 12:30 a.m.

— From a press release by Birch Aquarium at Scripps

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