SAINT-LOUIS, Senegal — By day, Saint-Louis native Pape Dieye is a boat captain-turned-tour guide for a fancy hotel that caters to Westerners. By night, he is a sought-after captain who vehemently turns down requests to smuggle human beings across the ocean.

The number of people attempting to make the perilous journey from West Africa to Spain has risen in recent years, and so has the demand for captains from Saint-Louis.

Those seeking to leave are mostly young and male, driven by the lack of jobs and a promise of opportunity on the other side of the ocean.

Captains in Saint-Louis have spent centuries mastering the ocean. They have built a reputation for expertly navigating dangerous waters and big waves in their long, narrow boats called pirogues.

"Because [captains] know the sea, they can pass when the wave is so big. They have a lot of experience," Dieye says.

Dieye can tell how deep the water is just by the color of the surface. He doesn't use GPS or a telephone. He knows how to find a school of fish with nothing but his fishing line. And he's not bothered by towering ocean waves or the black of night.

"They have to [teach] you how to drive a pirogue in the night because it is so dark," he says. "Because other times we [don't have the] technology. You have to know the stars."

Dieye says studying Saint-Louis' topography is also a must.

"You have to know how to pass the mouth where the river and sea meet," he says.

The island rests along an estuary where the Atlantic Ocean and the Senegal River come together, and Dieye thinks this is why his hometown produces those large and powerful waves.

When people ask him to captain a boat to Europe, Dieye says no.

"I didn't want to take people in danger, because when a person dies, it is my responsibility," he says.

"I didn't want to take some people that didn't know the sea."

Long days in the sea can lead to fatigue, seasickness, and even hallucinations. Having little to no experience on the ocean can raise these risks. People who attempted the boat journey to Europe told NPR that passengers on their boat experienced psychotic episodes.

Years ago, one of Dieye's friends knocked on his door at midnight. He was going to Spain, despite Dieye's warnings.

"I try to address him not to go, to stay here. But he was so angry with me," Dieye says.

His refusal makes a lot of people angry. He told his friend what he tells everyone: that it was not worth the risk. He fears people could die at sea, or he could be arrested trying to smuggle them into Europe.

"I work here; I have my family, my life is here," he says.

Dieye is a self-described optimist. He thinks things will get better, especially if young people invest time in their own country.

"With the effort they made in order to go to Spain, if they stayed here, with good training for example, they can succeed in something," he says.

For now, he hopes to share this message with anyone who listens.