Vieques, Puerto Rico (CNN) — Looking down into the undisturbed black water during a new moon, tiny pinpoints of light sparkle back, almost like a star field below matches the star field above.
Each paddle stroke creates a tear-drop glow, and the water's rippling crests glimmer in the darkness.
Splashing your paddling mate is hard to resist. When you do, you'll see that after the initial powerful glow, individual dinoflagellates will continue to fire for about 10 seconds, creating intermittent sparkles.
These tiny sparkles lead to some wondrous, drug-free hand staring.
This dazzling, trippy travel wonder is Mosquito Bay, the brightest bioluminescent bay in the world. It's on the Puerto Rican island of Vieques, seven miles off the southeast coast of Puerto Rico's main island.
Tranquil Vieques suffered extensive damage from Hurricane Maria in 2017, and some destruction has not been repaired. But Mosquito Bay itself has more than recovered.
"Guides and researchers say it is glowing better than ever," according to Mark Martin of the conservation group Vieques Island Trust.
Dinoflagellates in the water create an eerie bioluminescence.
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Bay bounces back
Abe Velasquez runs a tour company on Vieques offering snorkeling and bioluminescent bay kayaking tours.
Velasquez lost his own home in the storm and stopped doing bay tours for nearly nine months after Maria because the glowing dinoflagellate population had plummeted. (A dinoflagellate is a one-celled aquatic organism with plant and animal characteristics).
But now he says the bay is "a lot brighter" than it was before Maria.
Pyrodinium bahamense is the dinoflagellate responsible for the bioluminescence of Mosquito Bay. As the name implies, the tiny organisms are present in the Bahamas and throughout the Caribbean, but they usually aren't concentrated enough to catch the notice of humans.
Samples show that in 2017 there were in the range of 100,000 dinoflagellates per liter in Mosquito Bay, a time when the bay was already known as the brightest in the world.
The population dropped off through the end of 2017 after Maria, but numbers began to bounce back and spiked to nearly 600,000 Pyrodinium bahamense per liter in June 2018. The concentration has come back down, but levels are still higher than before Hurricane Maria.
Agitating the water causes the tiny organisms to glow.
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The bay's best show
Swimming in the water is prohibited to avoid exposing dinoflagellates to harmful human urine, but you can dip your hands in to create glowing swirls and splashes.
The brightness is relative to how much you agitate the water. A harder stroke produces more light. An overcast new moon is optimal for seeing the bioluminescence.
Paddling near the mangroves on a dark, moonless night, large glowing zigzag patterns appear and disappear in the water as fish dart to escape approaching kayaks.
Nurse sharks, rays and even manatees are sometimes in the bay -- outlined by eerie, glowing sparkles.
Guides say Mosquito Bay is not named after the bloodsucking insect but after a pirate ship called El Mosquito. Repellent without the harmful chemical DEET seems to keep insects away.
Vieques is also home to a range of peaceful beaches.
Attractions across the island
While Vieques has two small towns, Isabel Segunda in the north and Esparanza in the south, the island is mostly undeveloped.
For decades, Vieques served as a bombing range for the US Navy for practice and testing. After years of protests in Vieques, as well as significant demonstrations in New York and elsewhere, the bombing ended in 2003.
The former bombing range was converted to a wildlife refuge that covers half the island. The refuge is open to visitors during the day and is home to some spectacular beaches.
One option is La Chiva, an excellent beach for snorkeling with a small cay you can swim to. Playa Caracas is another easily accessible, beautiful white sand beach. If you'd prefer black sand, they have that, too, at Playa Negra.
Horses roam freely throughout the island.
Some are truly wild, but many are domesticated, owned, free-range horses. The waters contain many aquatic animals including sea turtles. On land they have iguanas and mongooses (but no snakes because of the mongooses).
Getting to Vieques can be an additional adventure. Regular puddle-jumper flights are available from San Juan and a few closer locations on Puerto Rico.
The more inexpensive option is to arrive by ferry -- with passenger-only and vehicle service available.
Motion sickness sufferers, pick your poison: a slower lilting ferry or a quicker bobbing plane. Either way, what you'll find on Vieques is well worth the journey.