Bay seniors who expect more out of a cruise here than circling Alcatraz listening to a spiel over a loud speaker, should check out the serious, scientific adventures offered by the Oceanic Society. The short version is a three hours investigation of the varied life of the Bay including megafauna and pinnipeds. $55. The Society’s tours to the Farallones are all day affairs above the Continental Shelf providing encounters with hump-backed whales, tufted puffins, rhinocerous auklets and dozens of other exotic species. $125. Both trips Saturdays and Sundays only.