During the day, the bay appears as a scenic part of a beautiful, tropical coastline. But when the sun goes down, it is transformed into a magical wonderland. Every movement and splash of water glows fluorescent from the microorganisms that live in the shallow waters. When agitated, they produce a blue light so as you splash in the waves or paddle through the waters you will light up the night. Mosquito Bay is Puerto Rico’s most popular bioluminescent bay. It was named after the famous pirate “El Mosquito”. It has about 160,000 microscopic plankton per liter of water making it the brightest bioluminescent bay in the world.