Fajardo’s Bioluminescent Lagoon Is Best Seen at Night

Visitors to Laguna Grande never fail to be amazed at the unique after-dark spectacle provided by this tropical bioluminescent lagoon as the water - or more specifically, the millions of dinoflagellates in the water - light up and glow in response to the slightest disturbance. Located on the east coast of Puerto Rico, in the municipality of Fajardo, the magnificent Laguna Grande is one of the most popular attractions among nature-lovers – but it must be visited at night, and the darker the night the better.

The glow in the water is caused by dinoflagellates (Pyrodimium bahamense), microscopic organisms found in abundance in these warm waters. It is thought that the ability of the dinoflagellates to light up is a chemical reaction forming part of their defense mechanism against predators. As they light up, they spotlight baitfish and crustaceans lurking in the dark waters planning to make a meal of them, thereby directing larger predators to these smaller predators – and creating a glowing sideshow in the process.

There are a number of tour options for visiting Puerto Rico’s Laguna Grande, depending on how adventurous you want to be. Kayaking is a popular choice and you don’t have to be an experienced kayaker to enjoy it. Launching from Las Croabas, a round-trip by kayak takes about two hours. Kayakers paddle their way through mangrove channels before arriving at Laguna Grande. You know you have arrived when your kayak is outlined in a beautiful blue-green glow, and every stroke of the paddles lights up the water. To minimize the impact of humans on this fragile eco-system, swimming is not permitted, but creating patterns in the water with your fingers has a magical quality about it and is fascinating. Eco-tourism guides are informative with regard to the dinoflagellates and conservation efforts, as well as the star constellations overhead which add an extra touch of magic to the experience.

For those who are not comfortable with kayaking or are traveling on a limited budget, there is the option of a leisurely stroll along the boardwalk winding its way through the mangrove swamp. Knowledgeable local guides will identify bird sounds, amphibians and plants of interest along the way. On arrival at Laguna Grande, visitors are given long stick with which to swirl and splash the water, creating glowing patterns. This activity sends fish swimming in all directions, leaving a trail of light behind them – an eerie and unforgettable sight seldom seen in other parts of the world.

There are three bioluminescent areas along the shores of Puerto Rico, with the other two being found at Lajas and off the island of Vieques. Puerto Rico is one of the few places in the world where bioluminescence is a year round phenomenon. A visit to Fajardo’s Laguna Grande can be a very rewarding experience and should certainly be on the list of things to see when visiting this picturesque region of Puerto Rico.

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