SAUSALITO, Calif. -- The humming starts softly under the artsy, mellow houseboat community anchored amidst the sea gulls and herons of picturesque Richardson Bay.
As the sun sets, the deep, resonating sound begins, getting louder with the darkness until it reaches such a pitch that it jangles houseboaters' nerves, giving them sleepless nights and grouchy demeanors.
For several years, the hum -- which only occurs in the summer -- was a mystery event ascribed to such various possibilities as a Russian submarine, a sewage disposal plant or even extraterrestrials.
'A lot of time, money and effort was spent by houseboat residents to track down the sound, then they called me,' says John McCosker, director of San Francisco's Steinhart Aquarium. 'They described it and I said, 'it's a toadfish.''
Looking like an oversized tadpole, the small fish live off the coast from Alaska to Mexico and enter bays and estuaries during summer months to breed, McCosker said. The males wait until sundown before attaching themselves to hard sub-strata surfaces, such as the cement hulls of houseboats, light up like fireflies and do the 98 hertz 'love hum' until sunrise.
'What's really strange is that the hum doesn't sound natural like it's part of the environment, it sounds electronic,' said Suzanne Simpson, a houseboat dweller and publicist who with other volunteers are turning their complaints into a celebration with a July 31 First Annual Sausalito Humming Toadfish Festival.
Suzanne Dunwell, a festival organizer who raises cockatiels aboard her houseboat, said there's not much that can be done about the sound, except live with it until the fish depart.
'It's like a Chinese water torture. As the night gets quieter, the humming gets louder,' Dunwell said. 'It may be the mating call of the toadfish, but it plays havoc with the sex lives of people living here.'
Simpson has solved some of the noise problem by moving the sleeping quarters from the lower to the upper deck of her lavender three-tier houseboat, but says the humming can still be heard in the still of the night.
'It was irritating. We couldn't sleep,' she says of the times she slept below the water line close to the humming. 'I drank a lot of brandy.'
Houseboater Lew Litzky said he first heard the hum four years ago and thought it was a generator problem. Later, he suspected the Russians of sending electronic signals through the water.
'On the plus side, it's one way to keep unwanted guests away,' he quipped. 'You give them the humming toadfish room.'
McCosker said he's captured some of the odd-shaped fish for a display at the Steinhart Aquarium and at the Toadfish Festival being held at the Bay Model in Sausalito, where he'll begin the day-long event by leading a humming toadfish kazoo parade. Some 25 environmental groups and 16 microbreweries are participating in the event along with musicians, mimes, jugglers and comedians.
'In the last century, people used to go out to the bays in the summertime to hear the humming fish,' said McCosker, adding that an amorous hummer about the size of a flattened-out hand can make 'a monstrous racket.'
The toadfish, which bury themselves in the mud on the bay's bottom during the day, apparently migrated to the houseboat area about four years ago and found the hulls a good place for their nocturnal 'hum of love' mating ritual. Ironically, says McCosker, successful efforts to clean up the bay will probably result in more toadfish colonies in the future.
'Some houseboat residents are upset that the hum comes from a fish because they can't sue anyone,' said McCosker. 'People have been closed out to the noises of nature while living on luxury condos in the water. I don't feel too sorry for them.'
