The Beauty of Puerto Rico's Bioluminescent Bays

The Puerto Mosquito Bioluminescent Bay on the island of Vieques, Puerto Rico, is a fascinating natural phenomenon which is quite rare, and absolutely spectacular. A visit to this popular attraction gives new meaning to the term “night life”, as the waters of the bay glow blue-green with every movement. Fish and other sea creatures appear to glow as they make their way through the waters. Kayaks and boats filled with mesmerized tourists are eerily outlined in the blue-green glow, and every splash of a paddle, or swirl of a hand, creates a magical glowing trail in the dark waters of the bay.

The glow in these warm waters is caused by countless microscopic organisms known as a dinoflagellates (Pyrodimium bahamense) which light up at the slightest disturbance. Researchers have concluded that the ability of the dinoflagellates to glow is as a result of a chemical reaction acting as a defense mechanism against predators. Small fish and some crustaceans are partial to a dinoflagellates dinner. However, as these predators move in the water the dinoflagellates light up, drawing the attention of larger predators - and the hunter becomes the hunted.

Although there are seven recorded places in the world where this natural phenomenon occurs – three of which are in Puerto Rican waters - it is widely accepted that the picturesque Puerto Mosquito Bio Bay is top of the list when it comes to the quality and brightness of the bioluminescent experience. There are a number of reasons for this. The shallowness of the waters and the narrow exit of the bay allow for a greater concentration of dinoflagellates, and while it is almost impossible to tell for sure, it is estimated that a single gallon of water can contain up to 720,000 of these single-celled organisms. Another reason for the high concentration of bioluminescence in the bay is the vitamin B12 released into the water by decomposing mangrove roots. This is an essential nutrient for dinoflagellates and Puerto Mosquito Bio Bay provides plenty.

There are a number of tour operators eager to introduce visitors to the wonders of Puerto Mosquito Bioluminescent Bay. Kayaking tours are a popular choice, with excursions on an electrically powered pontoon being another option. Conservation of this precious resource is taken seriously by islanders, and due to the fragile nature of this unique eco-system, diesel powered boats are not permitted in the bay.

Those who have enjoyed the experience agree that the best time to visit the bay is on the first and second nights following a full moon. The reason for this is that on the first night the moon rises an hour after sunset, while on the second night it rises two hours after sunset. This allows visitors time to enjoy the bioluminescence of the bay in darkness, and then have the bonus of watching the moon rising in the night sky. While the Puerto Mosquito Bioluminescent Bay is at its most spectacular when the night sky is darkest, it is worth visiting at any time of the month and any time of the year. If you are holidaying in Puerto Rico, this is an attraction that is just too good to miss.