Our main reason for going to Vieques — an island part of the Puerto Rican archipelago — was to see the bioluminescent bay. It contains up to 160,000 microscopic dinoflagelates per liter of water. When agitated, these microscopic organisms (Pyrodinium bahamense or swirling fire) react emitting a blue-green light for about a decimal of a second. There are other bioluminescent bays around the island, but the Mosquito Bio Bay is the one that shines with the most intensity, its shallow and small entrance from the sea impedes the waves from washing away the dinoflagellates; and the mangrove trees, with their decomposition process, provides abundant food for the micro-organisms.

No moon, only stars. (The bright star in the middle of the left side is Sirius — pointed to by the 3 stars in Orion’s belt.)
In order to see the bioluminescence at its best we traveled during the new moon so the nights would be especially dark.

The interior of the bus was painted with sea creatures and lit with a black light to allow our eyes to adjust to the darkness.
We met up with our travel companions just down the street from where we were staying. Each of us was issued a personal flotation device. Then we boarded a small bus driven by Eduardo who informed us of what we would do and see on our tour.

Ours are the kayaks on the left — completely clear so we could see the luminescent microorganisms as we paddled through the bay.
We disembarked at the edge of Mosquito Bay* where we met up with our guides: Eloy and Jimmy. Eloy gave us a paddling lesson and Jimmy led us while we were in the water.

The luminescence is difficult to capture in a photo. (The horizontal line is the gunwale of the clear canoe.)
Jimmy took us to different areas of the bay as he told us ecological facts and legend. He was also very good at showing us constellations in the night sky.

We enjoyed our trip.
Even though this is not a good photo opportunity the bioluminescent bay in Vieques is a magical sight on a dark night. It’s the reason we went to Vieques and we were not disappointed.
Jo
* Mosquito Bay is not named because of mosquitoes — there were none — but for a pirate ship that used to hide there. Mosquito Bay is named after “El Mosquito,” a small ship owned by Roberto Cofresí, a pirate who was a Robin Hood-type character. Cofresí often hid El Mosquito in the bioluminescent bay, which was connected to the ocean by a small, easily defensible inlet.