“If you take the long view, Vieques will end up better off,” said Mr. Martin-Bras, a biologist who came to work at the Bioluminescent Bay, the ecological marvel that draws visitors from all over the world. “The infrastructure will be stronger. We were on the cusp of a tourism boom; there was the W Hotel, there was talk of cruise ships. Would that be good for the island, or the appeal of the island? Probably not. So now that we have the essentials covered — there’s food in the supermarkets, beer in the bars, music in the streets — we have a chance to create tourism that’s more community-oriented, more nature-oriented, that can preserve and conserve the island, that’s more sustainable.”

The trust’s base, a tidy museum in Esperanza that houses nature and history exhibits has reopened. The W Hotel, with 156 rooms the island’s biggest hotel, has not. Its formerly manicured grounds remain gated; a spokeswoman for Starwood, which owns the W, said the reopening date was “up in the air,” and depended on when the power grid was restored so that repair work could be undertaken. Its closing represents a significant loss of jobs and revenue. Tourism accounts for 65 percent or more of the economy, according to Bob Gevinski, a board member of the Puerto Rico Hotel and Tourism Association and manager of the Hix Island House on Vieques.

The Bio Bay has suffered, too. On an earlier trip I had paddled it at night, plankton glowing magically as I let my hands drift through the water or a fish waggled by. I’d planned this trip to coincide with a moonless sky — the best time to see the glow — and had corresponded with BlackBeard Sports to line up a Bio Bay excursion, or perhaps snorkel or bicycle to the sugar industry ruins in the island’s interior.