5 facts about Vieques' bioluminescent Mosquito Bay

October 31, 2016, 6:49 a.m.
Kayakers delight in the bioluminescence of Mosquito Bay in Vieques, Puerto Rico.
Photo: Puerto Rico Tourism Company

From Japan to Mexico, there are numerous marine ecosystems around the world that boast high levels of bioluminescence. One of the most famous, Mosquito Bay, is found on the Caribbean island of Vieques, just off the coast of Puerto Rico. In this little body of water lives Pyrodinium bahamense, a dinoflagellate that glows a greenish-blue when agitated.

The best way to enjoy the beauty of Mosquito Bay is to book a starlit kayak trip. Here are a few things to know before you go!

1. It's the brightest bioluminescent bay in the world

If "visit a bioluminescent bay" is on your bucket list, then look no further. Mosquito Bay is, without question, the brightest and most reliable example of this phenomenon in the world. It's important to point out that Mosquito Bay is touted as the brightest not because Pyrodinium bahamense is a physiologically brighter species than any other bioluminescent critter, but because it's home to the largest concentration of these creatures.

On average, there are about 700,000 of these individual organisms per gallon of water, though some areas in the bay — such as the waters surrounded by groves of red mangrove trees — offer an extra bright show. Why? Because as mangrove leaves fall into the water and decay, they provide an optimal, nutrient-rich habitat for Pyrodinium bahamense to grow.

2. Sorry, no swimming allowed!

Like many wonders in nature, bioluminescent bays like Mosquito Bay go through cycles. Some years are brighter than others. However, recently, marine scientists and Viequean locals have noticed that the overall brightness of the bay has dimmed.

Since the U.S. military vacated the island in 2003, Vieques has spent the last decade and a half playing up its natural asset to attract tourists. Locals have swum in Mosquito Bay for centuries with no trouble, but the unprecedented influx of visitors is believed to be causing serious damage to the dinoflagellates. Specifically, the cause of the problem is suspected to have something to do with the oils of human skin and hair — not to mention all the lotions, sunscreen, perfume, insect repellent, shampoo and other chemicals that coat our bodies.

To protect this natural resource for generations to come, laws have been passed that ban swimming in the bay, though you're still allowed to dip your hands and feet in the water from your kayak.

3. Mosquito Bay is named in honor of a pirate, not those pesky bloodsuckers

With the looming fear of the zika virus, you might wonder if it's best to skip a visit to a place dubbed "Mosquito Bay," but rest assured, this is actually a misnomer! 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.

Unfortunately, this misnomer has led many tourists to douse themselves in DEET and other insect repellent before entering the bay, which as we've already explained, can do serious harm to the dinoflagellates.

4. Taking photos of this phenomena is more difficult than you think

It's difficult to adequately capture the sublime experience of witnessing these glowing waters, but that hasn't stopped many photographers from trying! It is possible to take outstanding photos of the bay in all its bioluminescent glory, but you need to be prepared with camera equipment that's not only waterproof but also performs well in low-light settings. Even tripod-toting photographers who are well-versed in the techniques of long-exposure photography may find photographing Mosquito Bay a challenge due the wobbly nature of kayaking. Still, as you can see above, it's definitely possible to capture some fantastic imagery if you know what to expect and plan accordingly.

5. The best time to visit Mosquito Bay is on nights with very little moonlight

This should come as no surprise, but the best time to schedule a trip to Mosquito Bay is when there's little or no moonlight shining down. That said, even on a full moon, the glow will be visible and awe-inspiring.