Stinson Beach reopened today, after the sighting of a great white shark forced a beach closing for swimmers. (Click here for shots from the Stinson Beach shark cam.) The beach had just reopened last Friday after a previous shark sighting mandated a 5-day closure last week too. If you weren't nervous enough, Stinson announces on its website that "attacks have happened in five feet of water and less than 50 feet from shore," and today, a dude minding his own business on the beach in Mendocino found the severed head of the abalone fisherman attacked by a shark last month.

While sharks do not deliberately target humans as prey, sometimes they mistake surfers for seals or sea lion (which they do target). If you're a scuba diver, experts suggest that you stay in kelpier areas (since sharks like open water), and if you're fishing, to put all bloody fish in the boat and not carry it around with you. In actuality, shark attacks are pretty unusual, but since when has SFist ever conducted ourselves with dignity and grace when confronted with rare yet totally completely terrifying prospects for danger in the Bay Area? Nope, we're going with irrational water-based fear again. (SFist is freaked out by the killer riptides at Ocean Beach too!)