Bioluminescent 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.

To access the bay by land you can either enter through the gate at Sun Bay or use the public entrance, which is the dirt track that lies just north of Sun Bay on Highway 997.

Bio Bay

Sun Bay Access (Playa de Don Flor)

Bioluminescent Bay, Vieques

Public Access site

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.

Bioluminescent Bay, Vieques

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.

Proposed Yacht Basin

1969 Navy Plans for the Bioluminescent Bay (Puerto Mosquito)

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 you bang on the sides of your kayak and scare the fish you will see the streaks of light they make underwater as they dart away from the sound. If it starts to rain, the whole bay will light up.

Truly an amazing experience!

There are several tour operators on Vieques through which you can arrange a visit to the Bio Bay either by kayak or on an electrically powered boat.

A Night at the Bioluminescent Bay
One night Habiba and I went to the Bio Bay with Abe, (Abe's Snorkeling and Bio Bay Tours) a really cool guide who has been going out to the bio bay since he was a kid and who really appreciates all it has to offer. We put our kayaks in at a beach called Playa de Don Flor that is accessible from the Sun Bay entrance.

We get in our kayaks and begin to paddle. There is no moon and it is almost totally dark. It is really dark.

That is, if you don't move.

But we are moving.

And everything and I mean everything is glowing and sparkling in electric greenish and bluish white light. The hulls of the kayaks and the paddles are on fire, and even the water dripping off the paddles stirs up the bioluminescence and little drops of light fall through the air like sparklers on the Fourth of July.

Surreal … totally.

And the fish are leaving twisting psychedelic jet streams behind them as they shoot away from the intruders into their territory. And some of the fish are pretty big. Even some sting rays. And they make a big light. What a trip!

Then we stop and are silent. The stars are shining above us and the air is crisp. It's a perfectly clear amazingly beautiful summer night and the three of us, Habiba, Abe and I, are there, in Mosquito Bay, in Vieques, in the Caribbean and on the beautiful planet that we are fortunate enough to inhabit. And we stop to catch our breath and we easily fall into a quiet meditation, listening to the sounds of the night, with millions of stars shining above us and casting their reflection onto the calm waters of the bay.