Art and Experience: As European leaders wrestle with a wave of migrants that is testing their commitment to open borders and their democracies, a documentary about the Italian island of Lampedusa — for years the first point of arrival in Europe for hundreds of thousands migrants from North Africa — has emerged as one of the strongest films at this year’s Berlin International Film Festival.

To make the documentary, “Fuocoammare,” or “Fire at Sea,” the Italian director Gianfranco Rosi spent long stretches on the tiny island, actually closer to Tunisia than to Sicily, as well as on an Italian military ship that rescues boats of migrants who risk their lives at sea to reach Europe. The film has had strong reviews since it was first shown here on Saturday, just days after NATO announcedit would send ships to intercept migrant boats in the Aegean.

“This is a problem that is jeopardizing the idea of Europe,” Mr. Rosi said in an interview here on Sunday. He called the deaths of thousands of migrants at sea the biggest tragedy facing Europe since the Holocaust.

In addition to the nameless migrants, “Fire at Sea” has two protagonists: Pietro Bartolo, the doctor on Lampedusa responsible for its 4,000 inhabitants and also for performing autopsies of dead migrants, and Samuele Puccilo, an ebullient 12-year-old. Mr. Rosi follows Samuele, including to the eye doctor, where he is treated for a lazy eye, an event that Mr. Rosi said served as a metaphor for Europe’s failure to see the migrant issue clearly.

The film is a series of intimate scenes: Rescue workers carrying suffering migrants off a boat for medical care; Dr. Bartolo performing an ultrasound on an African woman pregnant with twins; the local D.J. taking calls for requests of Sicilian songs, including the one that lends the film its name; Samuele lovingly making a slingshot to hit birds.

The heart of the film is a monologue by Dr. Bartolo, which Mr. Rosi shot just weeks before the film was shown in Berlin. In it, the doctor says he has “a hole in his stomach” and nightmares from performing autopsies on dead migrants who have arrived over the years, including many children.

Dr. Bartolo lent an emotional power to a news conference here for the film on Saturday. He spoke of a boat that sank last year off Lampedusa. Some reports put the death count at 366. “It’s 368, not 366, Dr. Bartolo said.

“I saw them one by one and I had to count them,” he added. “Two isn’t a number. They’re two people.”

Mr. Rosi spent two, three-week tours on an Italian military ship patrolling the waters off Lampedusa. Last August, the ship intercepted a steady stream of boats, including one in which 49 people had suffocated in the ship’s hold.

The director said that he was reluctant to film the dead, but the boat’s captain convinced him otherwise: “He said, ‘Gianfranco, it’s like if you were in front of a gas chamber during the war and someone said, I’m not going to film that because it’s too hard.’”