Biobay: A Sea that Glows at Night

It was Ang Lee’s Oscar-winning movie, Life of Pi, that thrilled spectators with the stunning beauty of ocean at night; in particular, when the bioluminescent fish create a cosmos underwater, illuminating the young Pi and his boat. While the computer-generated visuals did the magic for the film, the natural phenomenon- bioluminescent bays-that light up sea at night keeps offering the spectacle at different corners of the Earth. The popular bioluminescent bays in the world include three bays in the waters near Puerto Rico, Jamaica’s Luminous Lagoon and Halong Bay in Vietnam.

Amongst the many wonders that form a part of the planet earth, there isn’t anything like the Bio Bay, located in the country of Puerto Rico. This bay is unique because it glows at night, turning into one of the most beautiful sights seen in the world. With the rich presence of Pyrodinium Bahamense, the single-celled organism behind the amazing phenomenon, Bio Bay stands as the brightest bioluminescent bay in the world. At night, when stars start blinking in the sky, Bio Bay treats the spectators with the amazing glow of blue-green light.

Location and Origin of Bio Bay

The Bioluminescent Bay, also known as Mosquito Bay, is located along the Caribbean coast on the southern shore of Vieques Island of Puerto Rico, which is a commonwealth of the United States.  Puerto Rico also features two other bio luminescent bays: one located in the Laguna Grande in the town of Fajardo, while the other can be found in La Parguera near the town of Lajas. The Vieques Islands, however, were under the Spanish colonization for nearly four centuries and are one of the constituents of the ‘Spanish Virgin Islands.’ Featuring a number of volcanic bedrock, sedimentary rocks in addition to several other geographic characteristics, Vieques Island remains one of the popular tourist destinations in the region. However, what makes the island most popular is nothing but the Bioluminescent Bay.

Marine Plankton glow in the dark in Thailand, bioluminescence – Credits:


The bioluminescent bay was created quite inadvertently while the Spaniards controlled the islands. Unaware of the botanical rationale behind the emission of the light, the Spaniards were under a misapprehension that the area was under a demonic influence. The Spanish believed that the phenomenon was the work of the devil and tried to bar the waters of the bay from entering the neighboring sea waters with huge rocks and stones. However, these blockages resulted in the bay being created and the resultant secluded ambiance allowing the dinoflagellates to breed much more effectively. The segregation and the alienation resulted in the creation of the necessary conditions for Mosquito Bay, such as it prevented any modern development around the bay and helped the growth of red mangrove trees in the surrounding areas. The attempt to choke off the bioluminescent bay from the ocean also resulted in the creation of a small channel, which now keeps the dinoflagellates in the bay.

Why does the Bio Bay glow?

Bioluminescence, which can also be referred to as luminescence in simple terms, is caused because of a reaction set off chemically by the microorganisms that dwell in the bay’s waters. The reaction acts as a defensive response by the organisms – known as dinoflagellates – when they sense the water being disquieted either by human contact or by the fishes that pass through. According to reports, there are up to 160,000 microscopic dinoflagellates per liter of the bay’s waters, turning the small chemical reactions into magic.

The chemical that sets off this reaction in the organisms is known as ‘luciferin.’ Hived away in the cell of the dinoflagellates, this chemical when coalesced with oxygen sheds an illuminating light. The secretion of the chemical is regulated automatically in the organism’s cell and is at its maximum at night time, leading to the unique panorama.

Image for representation purpose only

This bioluminescence is further heightened by the facts that the bay’s depth is quite insufficient and also because of the dense foliage of mangroves. The leaves of the trees fall into the water and in their decomposition, germinate vitamin B-rich bacteria. The dinoflagellates consume this bacterium which further accounts for their increment in the bio bay. Another yet important reason for the dinoflagellates existing in the bay is because of its restricted outlet to the sea. The limited space accounts for the organisms to proliferate and thrive in the bay.

Bio Bay-a tourist attraction

The majority area of the Vieques Island was closed for quite long years by the US Navy, leaving the region undeveloped for decades. However, this very lack of developments now brought the island into the forefront of tourism as its unintentionally preserved natural beauties are attracting visitors around the world. Being promoted as an unspoiled land, with splendid geographical characteristics, Vieques is rapidly becoming a popular destination in the Americas.

Among the magnificent waters along the Caribbean coast, mosquito bay has been officially declared as the brightest by Guinness Book of World Records 2008, making the bay is a source of great tourist attraction from far and wide.  While bioluminescence is seasonal in other parts of the world the water off Vieques Island reportedly glows brightly year-round, strengthening its position as a major tourist destination. In contemporary times, as a recreational and adventure activity, canoeing is permitted in the bay waters of the Vieques Islands. Even though tourists are restricted from swimming and using motorized boats in the waters, kayaks help them to feel the water and its blue-green light under the new-moon.  The advertising promos also feature this part of the Vieques as being a major-scale tourist area, further augmenting the popularity of the island and the biobay in duality.

In order to preserve the unique eco-system that is sustained in the bay’s waters, several efforts are also being made to ensure that this uniqueness does not dissipate to due to unwanted activities. It can be hoped that in the light of several problems plaguing the many singular oceanic areas in the world, the beauty and wonder of the bioluminescent bay is retained substantially.

Disclaimer: The authors’ views expressed in this article do not necessarily reflect the views of Marine Insight. Data and charts, if used, in the article have been sourced from available information and have not been authenticated by any statutory authority. The author and Marine Insight do not claim it to be accurate nor accept any responsibility for the same. The views constitute only the opinions and do not constitute any guidelines or recommendation on any course of action to be followed by the reader.

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One Comment

  1. I’ve always wanted to go to Bio Bay! When I found out swimming wasn’t usually allowed, I was a little disappointed, but kayaking sounds fun too. I don’t think I’ll be able to make a trip out there any time soon though. My boyfriend knew how much I wanted to go, and ended up getting me a really amazing gift. It’s a Dino Sphere, and it’s made by a company called Biopop. It’s a glass sculpture filled with dinofllagellates, so they use the chemical process described in the article to produce bioliminescence! I just wanted to share because I thought it was a neat way to experience bioluminescence at home if you can’t travel to Bio Bay or another spot where it occurs naturally.

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