Puerto Rico has the largest wildlife sanctuary in the Caribbean, but the island’s most intriguing and interesting place is the bioluminescent mosquito bay, which is located along the south shores of Vieques.

When you travel to Vieques, one of the first things you should do is explore Mosquito Bay. This natural phenomenon is the most active and thriving bio bay in Puerto Rico. Bioluminescence is a natural, but spectacular undersea occurrence found in the Caribbean and around the world.

Bioluminescent Bay gets its name from the millions of small living organisms called luminescent dinoflagellates (aka Pyrodinium bahamense) that live in the warm Caribbean waters. They produce a mysterious blue-green glow of light when disturbed. The light that comes from these organisms is brighter and more luminous than in any other bio-bay around the island. Most people would say Mosquito Bay is the most beautiful place to see bioluminescence.

Mosquito Bay has the highest concentrations of Pyrodinium bahamense. You may find flourishing concentrations of Pyrodinium in the lagoon, a little ways downwind from the entrance of the bay, surrounded by mangroves. The leaves that drop from the mangroves provide food for the Pyrodinium.

Vieques offers night tours of Mosquito Bio Bay that you can sign up for while visiting Puerto Rico. As you kayak through the water, you can see the Pyrodinium bahamense by the light they produce as they scatter around your paddles. You may even be amazed by the intensity of this light as it surrounds your kayak. This intensity lights of the Mosquito Bay and can be seen from far away.

To protect Mosquito Bio Bay and the fragile wildlife that live within it, you won’t be able to enter the water to swim or interact with the Pyrodinium bahamense. Unless you choose to go night kayaking in Bioluminescent Bay on your own, taking a tour of the bio bay may be ideal.