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Paddling over underwater fireworks in Mosquito Bay

Puerto Rico – Puerto Rico Tour Desk

As I set out across Mosquito Bay on a moonless night, the water below my glass-bottom kayak twinkles brighter than the stars above. I skim across a sea of diamonds. Every stroke of my paddle stirs up an explosion of blue-white light. I am on Vieques, a small island an hour by ferry off eastern Puerto Rico, in the middle of what’s reputed to be the brightest bioluminescent bay in the world.

The light show is caused by microscopic plankton called dinoflagellates that glow when agitated; paddles, kayaks or splashing hands set off the fireworks. So do fish – schools of them skitter by like underwater glow sticks. Deeper down, a huge yellow shadow passes under my kayak. “What’s that?” I ask our guide. “Probably a tarpon,” he says, “Eighty or 90 pounds.” The original inhabitants of Vieques believed the tiny lights were stars fallen from heaven. When the Spanish conquered Puerto Rico, they concluded it was the work of the devil.

Now the so-called Bio Bay is a magnet for tourist dollars and the island is fighting to make sure the lights don’t go out, as they have elsewhere and recently did here for six months.

Pollution and red tide produce a glowing effect in many parts of the oceans but there are only a handful of bays in the world lit up by the light energy of dinoflagellates. Three are in Puerto Rico, and Mosquito Bay is the most intense of them all. As eight double kayaks gather round, our guide explains why. The bay has an extremely narrow opening to the Caribbean, which prevents dinoflagellates from being washed out to sea by the tides. They thrive in the warm, shallow water on nutrients from mangroves that surround the bay. And the relatively remote and undeveloped location means less pollution.

Vieques (pronounced Bee-eck-iss) was controlled by the U.S. Navy and used as a practice bombing range until protests forced it to pull out in 2003. Some parts of the island are still off limits because of unexploded ordnance. The military presence discouraged tourism – there is only one modern resort on the island – and most of its sweeping white-sand beaches are best known by the coloured flags that the Americans used for training exercises. Our favourite, Navio Caracas, is called Red Beach; Punta Arenas, at the west end of the island, is dubbed Green Beach. Home to just 10,000 people, Vieques evokes what many Caribbean islands must have been like before the invasion of all-inclusives – an estimated 3,000 wild horses roam free on the island, all but the main roads are so rough that most rental cars are four-wheel drive and beaches are lined with nothing but palm trees. While swimming and snorkelling are big draws, the main moneymaker is the Bio Bay.

Every night, except around the full moon when bright light obscures the bioluminescence, hundreds of tourists take to the water in kayaks or, for the less adventurous, an electric boat. Thirteen companies are licensed to run tours. Most are from mainland Puerto Rico and the United States; we go out with JAK Water Sports, the only local operator. After assembling in a beach parking lot, 15 of us climb on a bus and bounce over a potholed dirt road to a beach on Mosquito Bay. It is pitch-black; our guides use flashlights to point us to our kayaks and hand out life jackets with tiny blue lights to help keep track of us on the water. Several other groups are also getting ready to launch, and each operator will have more clients ready to go when we come in.

At $60 (U.S.) for a two-hour outing, it’s a lucrative business but it dried up in early 2017 when the bioluminescent effect suddenly dimmed. Tours were limited to weekends only and paddlers had to make do with the stars in the sky, as government officials and scientists tried to figure out what had happened. Some speculated that unusually strong waves and currents had diluted the plankton; others suspected overuse and contamination from sewage and runoff from nearby farms and construction. There’s still no clear answer, though the need for one declined when the lights came back on in July, as bright as ever.

Some protective measures were already in place – gas-fuelled motorboats and swimming were banned several years ago, but those rules were flouted, often by unlicensed tour operators. After the blackout, enforcement was stepped up. The road into the bay was improved, sediment traps were built and more native species were planted, all to reduce runoff. A new “real-time” monitoring station was installed in the middle of the bay to provide better information about water quality, temperatures and tides.

As we paddle, the gleeful wonder at the flickering below gets louder when a fish jumps from the water and hits one paddler in the head. Something else also makes the experience unique: It requires special camera techniques to capture the bioluminescent effect, so it’s a rare adventure where no one bothers to pull out a smartphone. Despite the lack of selfies, tourists will keep coming, as long as the rush to cash in doesn’t trump efforts to ensure the lights stay on.


The Globe and Mail