(c) Travel and Leisure Nov 1993
by Tom Verde

Tom Verde wrote: Down by the Bio Bay There are few places on earth where you can still see fire gods. Mosquito Bay, on the Puerto Rican island of Vieques, is one of them. [Daytime PHOTO] A Typical Caribbean shoreline by day, Mosquito Bay shines at night - with a bioluminescent glow that's almost impossible to photograph. Some 4,000 years ago a band of Archaic Indians worshipped the gods of this bay, who provided food by day and green fire by night. Today visitors come not to worship but to marvel at Mosquito Bay, and to swim in its eerily glowing waters after dark. Thatís when the gods- tiny bioluminescent organisms thriving near the surface- reveal themselves. "People often tell me this is the most incredible thing theyíve ever seen," says Sharon Grasso who runs tours of the 160 acre bay in an electrically powered pontoon boat. A former Connecticut high school science teacher, Grasso is among a coterie of grassroots conservationists fighting to preserve Mosquito Bay, one of the worldís few remaining and most extraordinary bioluminescent bays, or "bio bay" for short. Tiny Vieques, six miles off the eastern tip of Puerto Rico, is a modest island for such an honor. Despite the appeal of its 40 plus palm-lined beached (both Gorgeous and empty) and proximity to San Juan (only a half-hour by plane), it remains off the beaten track. Thatís due largely to the U.S. military, whose occupation of two thirds of the islandís necessarily curbs development Mosquito Bayís glow comes from dinoflagellates, microscopic underwater organisms that release energy in the form of light, much the way fireflies do. Several dinoflagellate species are found in oceans worldwide: on the U.S Atlantic coast, the waters around Borneo and the Sea of Japan. Although in some places bioluminescence is seasonal, Mosquito Bay glows year-round, thanks to a plentiful population of the species Pyrodinium bahamense, whose name means "whirling fire." Only 1/500 inch in diameter, these organisms flash when agitated, probably as a defense mechanism. Each flash last only 1/10 second, yet the collective greenish blue radiance can be seen for miles. The reason for this intensity, says John Hopkinsí Howard Seliger, a pioneer in the study of bioluminescent bays, is Mosquito Bayís high concentration of dinoflagellates 720,000 per gallon. As darkness falls across the bay, the wake of Grassoís pontoon boat begins to glow- a luminous emerald path of foam lingering behind the stern. There are other boats on the water, too, but you can hardly see them - only their wakes, shining like the lights of distant cities. "Try stamping on the deck, " Grasso suggests. When we do, a comet-like flash of light suddenly crosses the bow. Then another, and another, and soon the surface is erupting with startled fish, their effulgent escapes routes streaking the black water like fireworks. "If weíre lucky," says Grasso, "weíll see a ray." Minutes later, someone catches sight of one, passing like a phantom below the surface, its graceful, undulating body shining green and bright in the darkness. As we near the center of the bay, Grasso cuts the engine and invites us to plunge in. The water is warm and brackish, and ghostly clouds of green-blue light boil around us. Whenever we break the surface, twinkling dots of light stream from our arms and hair like fairy dust. It is the stuff of midsummer night enchantment. Yet it is not magic but an extremely fragile ecosystem that makes this topical lagoon so marvelous. Mosquito Bayís narrow mouth prevents many of the dinoflagellates from being flushed out to sea, while decaying roots and leaves from mangrove swamps provide the organisms with food. Itís a delicate balance. Alter the channel and the exchange rate of water is thrown off; disturb the mangroves and the food source is imperiled. Bio bays in other parts of the Caribbean have been lost because of development and pollution. At La Paguera on Puerto Ricoís southwest coast, Bahia Fosforescente, once said to be as fantastic a Mosquito Bay, is now 1/10 as bright as it used to be, Thanks to the intrusion of powerboats, Jet Skis, and lights from the town that sprang up as a result of the bayís popularity. (Bright lights make bioluminescence harder to see.) Occupants of illegal water front houses are also accused of cutting mangroves for firewood and polluting the area with sewage. There are those on Vieques who are simply unwilling to let this happen to Mosquito Bay. Grasso, for instance, has been leading a campaign against gas-powered boats; a ban would reduce pollution from bilge water and leaking engines. The biggest push to save Mosquito Bay , however, has come from the Vieques Conservation and Historical Trust, founded in 1985 with the explicit purpose of preserving the islandís bioluminescent waters. First the trust tried to buy the land from around the bay from the Puerto Rican Industrial Development Corporation, a government agency that owns and develops land for tourism and industry.