The World's Best Bio Bay
"Mosquito Bay, also known as the Bioluminescent Bay, on the south coast of Vieques is undoubtedly the healthiest and best example of a bioluminescent bay in the world. With the slightest agitation of the water tiny bioluminescent creatures emit an electric bluish white light.
Fish swimming in the bay leave a bioluminescent trail as do boats, raindrops and people swimming. This phenomenon of bioluminescence is so intense, so awe-inspiringly beautiful and so dependable that Mosquito Bay in Vieques, also called the Bioluminescent Bay or the Bio Bay, could easily be called the eighth wonder of the world.
The organisms responsible for bioluminescence are called dinoflagellates. They can be found in all waters of the ocean as plankton, tiny organisms that live just below the ocean's surface. They have the ability to move via a whip-like tail, but are so small they travel at the mercy of the winds, waves, currents and tides.
Special characteristics of certain bays throughout the world create conditions in which dinoflagellates will concentrate and flourish. Mosquito Bay in Vieques is a perfect example of such a bay. The mouth of the bay is situated in such a way that the prevailing winds and currents easily allow ocean water to enter the bay. It is also quite shallow at the entrance so that only the surface waters, which are abundant in plankton, flow into the bay. A relatively narrow channel winds into a large shallow mangrove lagoon downwind from the entrance.
Here the bioluminescent organisms will concentrate because they can't get out of the bay. They're too small and not fast enough swimmers to find their way upstream snaking through the channel to return to the open ocean. Nor would they want to, because the conditions in the Bio Bay's mangrove lagoon are just right for them.
The entire bay is encircled by mangroves whose leaves are constantly falling into the water. These rotting leaves provide a perfect diet for the dinoflagellates. Moreover, the salinity of the water is perfectly suitable to the dinoflagellates. It is kept within their narrow tolerance levels because of the presence of lagunas or salt ponds just behind the mangrove lagoon that collect water during periods of high tides and during intense rains and filter the fresh water back slowly afterward.
Another important factor is that there is no significant quebrada or fresh water stream leading into the bio bay that could lower the salinity to undesirable levels. Human contamination from sewage, a factor which has seriously degraded a bioluminescent bay on the Big Island, which was once a rival to Mosquito Bay, is not a problem in Vieques, and hopefully never will be.
Tests have shown that the Bioluminescent Bay in Vieques contains as many as 720,000 bioluminescent organisms per gallon of water. This concentration is so great that if you splash the water you will cause them to emit enough light so that you could read the print on a book in the dead of night.
Dinoflagellates are non-toxic and you can get in the Bio Bay and swim around with them, and your whole body will be encircled by an unbelievable aura of light. If you splash water on your hair it will drip crystals of light like tiny sparkling jewels. If it starts to rain, the whole bay will light up. Truly an amazing experience!"
From the book "Vieques" by Gerald Singer