My guess would be because of the shark attacks we get in the area from time to time. (not meant to be sarcastic; it's really an issue) Besides, Bay water is coooooooold You can get hypothermia in June if you're not careful. One last thing...the Chinese freighters that frequent the Bay don't bother with pumping their sewage into treatment tanks before pumping it overboard. My old Scout boat is docked right next to a pier that Asian scrap-metal ships frequent...and you don't want to know what I've seen in the surrounding water when there's a ship in-port...