Salt River Bay bioluminescent kayak tour

Paddle into Salt River Bay after dark and every stroke leaves a trail of light in the water. The glow comes from a single-celled plankton, Pyrodinium bahamense, which flashes when disturbed, with comb jellies and fireworms adding their own. Bays that glow all year are rare in the Caribbean, and this is one of two on St. Croix.

The kayaks set off from the Salt River Marina at nightfall for about two hours and a mile and a half of paddling through the mangroves. Depending on the outfit you sit in a see-through kayak, a glass-bottomed one, or a pedal kayak that leaves your hands free. No swimming in the bay: it harms the plankton and the bay is a nursery for lemon sharks. DEET repellent is banned too, and the guides hand out a picaridin lotion instead. Expect to get splashed, so wear swimwear or quick-dry clothes. The glow needs a dark sky, so near the full moon the outfitters run moonlight or sunset paddles instead. Light rain does not dim it. Children usually have to be at least 8.

By day the same bay is a national historical park, where a landing party from Columbus's second voyage came ashore in 1493.