“Everything has converged here all at once,” said Jean-Pierre Oriol, commissioner of the territory’s department of planning and natural resources, who has worked there for two decades. “I’ve never seen the volume here in the territory that we have right now.”

At the end of March, New Jersey residents Carol and David Hewit were on their Island Packet sailboat, about a quarter mile from the Dutch island of Sint Eustatius, when, Mrs. Hewit recalled, “we were greeted as we entered their only harbor with bullhorns and boats.”

They turned around and sailed through the night to the U.S. Virgin Islands.

Now moored on Francis Bay in St. John, the couple, who are in their 60s, say they do not want to return home; the New York area is now the pandemic’s epicenter. Like many sailors, they do not want to leave their boats by flying home — if they could even get a flight out; theirs, for later this month, has already been canceled.

Their son, based in midtown New York, has moved his family, including their infant grandson, into the couple’s home, and the Hewits fear contracting the virus on the plane and passing it along.

Many mariners like the Hewits plan to ride out the pandemic on islands, choosing what appears their safest option in an ever-changing set of unknowns.

But Marvin A. Blyden, a territory senate leader who has drafted several pieces of legislation regarding the mariners since their arrival, worries that playing safe haven for guests will prove dangerous for residents.

“We don’t have the resources to deal with the large influx,” he said. “Yes, we’re an American system. Yes, we should look to help those in need. But at the same time we must protect our borders and we must protect our people.”