KEY WEST, Fla. >> A second day of searching an area the size of Hawaii failed to turn up any sign of 10 Cuban migrants lost at sea after the boat they were traveling in sank off the Florida Keys, Coast Guard officials said today.

At least two people died and eight people survived the voyage after the boat carrying 20 people out of the Port of Mariel in Cuba overturned Wednesday night off Key West, Florida, according to the authorities.

A Coast Guard cutter had been patrolling the Straits of Florida, about 18 miles southwest of Key West, when it encountered some of the boat’s passengers in the water around 1 p.m. Thursday, officials said.

A lookout first spotted what appeared to be a person in the water, Capt. Adam Chamie, commander of the Coast Guard’s Key West sector, said in an interview. “They diverted to investigate, and sure enough, it wasn’t one people, but several,” he said.

There was no sign of their boat.

The survivors, six men and two women, were brought on board the cutter, where they were reported to be in good condition, he said. Two men whose bodies were recovered were taken to the Monroe County Medical Examiner’s Office for autopsies.

The Coast Guard, the Navy, the Florida Fish and Wildlife Conservation Commission, and U.S. Customs and Border Protection sent ships, planes and helicopters to search for the 10 missing passengers. They covered a 6,500-square-mile area with no additional signs of people or debris, Chamie said.

People could generally survive in the late spring waters for as long as three days, depending on wind and other factors, he said. The occupants of the boat were not believed to be wearing life jackets. He said the agency would continue to assess the search and decide how long to keep looking.

“Just imagine treading water in a pool for a half-hour,” Chamie said. “This is difficult. It does not mean it’s not possible. That’s why we continue to search to give them every chance if they are still swimming and on top of that water. We don’t know what they might have clinged to.”

It was not immediately clear what type of boat was involved, although based on most of the migrant boats encountered recently by the Coast Guard, it was probably fragile and overcrowded, he said.

“I can tell you in generalities what we have seen over the years is that these vessels are not solid construction,” he said. “They’re often, almost always, unseaworthy. These vessels are almost always taking on water.”

The survivors said they left Cuba on Sunday but did not explain how their boat sank, the captain said.

The Monroe County medical examiner, Dr. Michael Steckbauer, said one of the two bodies taken to his office had been identified. People have been calling the office to inquire whether the men were family members, Steckbauer said.

At just 90 miles from Cuba, the Florida Keys have long been a frequent passageway for Cubans trying to make it to the United States. But Coast Guard officials have warned about the perils of making the journey.

There has been a recent increase in the number of Cubans traveling to the United States aboard unseaworthy handmade vessels, Coast Guard officials said, particularly over the past week of warm weather and calm winds.

The Coast Guard said it had captured nearly 300 Cubans at sea since the start of the fiscal year in October, the largest surge since 2017. Last fiscal year, 49 Cubans were caught trying to migrate by sea to the United States.

The surge in migrants coming from Cuba is a sign of worsening conditions on the island, experts said. The country recently unified its dual currency, which caused the value of the local peso to plummet. Food scarcities are the worst in decades.

“What you are seeing is not frustration, but desperation,” Katrin Hansing, a Cuba scholar at Baruch College in New York, said Friday after returning from a monthslong research trip to the island. “People are so desperate that they are willing to go on these suicide missions.”

© 2021 The New York Times Company