@ebrpd: With September comes the end of Grunion Run season! California grunion are these small, silver fish you see wiggling their way up the beach to lay their eggs in wet sand. They emerge near midnight during new and full moons, and they are easiest to see with red-filtered flashlights to avoid spooking the fish. A female grunion swims up the beach's slope and digs tail-first into the sand, leaving only her head exposed. After she deposits her eggs, males will wrap around her to fertilize the clutch before they all shimmy back into the surf. Females can lay between 1,600 and 3,600 eggs during one spawn, with as many as eight males fertilizing eggs in a single nest. Eggs are laid during high tide, incubate during low tide, and hatch about 10 days later, when the tide comes back in. California grunion are far more common in Southern California and northern Baja California than in the Bay Area, but even in the south their populations face threats from coastal development, beach erosion, and pollution, and their peak spawning season is protected. Because many East Bay Regional Park District shorelines close at sunset, the best way to witness a run is on a guided program. Check our calendar next spring for naturalist-led grunion events running April through July. #WildlifeWednesday #eastbayregionalparks #fish #nature

East Bay Regional Parks

Open In TikTok:

Region: US

Wednesday 02 September 2026 22:10:47 GMT