Bioluminescent Bays of Vieques, Puerto Rico

Imagine going for a night swim in warm tropical waters… sound nice? Well, the Bioluminescent Bay off Puerto Mosquito on Puerto Rico’s Vieques Island steps things up a notch. Unique environmental conditions in the bay result in high concentrations of a certain microscopic organism called a dinoflagellate. This tiny creature, half plant and half animal, emits light when disturbed. The ethereal bluish light is called bioluminescence and is similar to the cold glow produced by fireflies. In optimum conditions more than 700,000 dinoflagellates can occupy each gallon of bay water. Anything moving in the water, whether a boat, fish or a swimmer, will cause the nearby dinoflagellates to light up. The effect is like something only a Hollywood special effects team could whip up, but in this case the Oscar goes to Mother Nature.

The tiny dinoflagellates are completely harmless and swimming with them (or in them) is a truly unforgettable experience. Every motion a swimmer makes is instantly surrounded by a glowing field of ghostly blue light, bright enough to read by – as if anyone would be reading a book with so much beauty to see in the sea!

Tourists to Puerto Rico who would like to experience a Bioluminescent Bay night swim should plan ahead so that they will have accommodations on Vieques Island for at least one night, and ideally the night should be mainly moonless so that the light show in the sea is not diluted by competition from above. Local tour operators have set up Eco-tours that allow visitors to enjoy the spectacular show put on by the Bioluminescent Bay’s dinoflagellates without degrading the unique conditions they need to survive and thrive. Electrically operated pontoon boats are quiet and non-polluting, or kayaks can be rented at the Puerto Mosquito docks. Vieques Island itself is easy to get to, either by air or by sea. It’s Puerto Rico’s “little secret” – one people find hard to keep!