Windsurfers, fishing boats and cargo ships aren't the only traffic in San Francisco Bay. Great white sharks are there sometimes, too.
In what is believed to be the first scientific confirmation of white sharks in San Francisco Bay, researchers from Stanford University, the University of California-Davis and other organizations put satellite and acoustic tags on 179 white sharks in Northern California waters between 2000 and 2008. They found that most of the sharks migrated thousands of miles every year, from California to as far away as Hawaii, and five swam underneath the Golden Gate Bridge in 2007 and 2008 and into bay waters.
It isn't known exactly where the sharks went once in the bay, only that their acoustic tags were detected by receivers anchored to the bay floor between the Golden Gate Bridge and Alcatraz Island.
"All we know so far is that they are poking their heads across the Golden Gate," said Barbara Block, a professor of biology at Stanford's Hopkins Marine Station in Pacific Grove who helped lead the tagging study. "I doubt they are coming in very far because they are saltwater animals."
