Monday March 31, 2025
San Francisco Chronicle —
Heavy rains left behind a thick carpet of jellyfish-like creatures at Bolinas Beach in Marin County on Sunday.
Approaching the beach with his two dogs around 8 a.m. Sunday, Del Dickson said he initially thought the sand was covered in a dark layer of gravel. Closer inspection revealed that “thousands and thousands” of floating hydrozoans known as “by-the-wind sailors” — scientific name Velella velella — had washed ashore overnight.
The sea animals looked from afar “like an oil slick” covering the water and sand, said Dickson, a retired professor who was visiting Bolinas with his wife and two dogs.
“There were rafts of them,” he said. “It was really amazing.”