Senegal's navy stopped more than 1,500 people trying to sail to Spain's Canary Islands over the weekend, it says.
Many would-be migrants drown in their attempts to reach Spain
Navy Captain Jean-Baptiste Faye said the migrants had been in 19 wooden boats and 60 people traffickers had been arrested.
"With the closing of [routes through] Mauritania and Morocco, they are starting to leave more and more from Senegal," he said.
A Spanish envoy is touring West Africa, trying to stop the flow of migrants.
Ambassador Miguel Angel Fernandez Mazarambroz is trying to persuade African governments to sign deals making it easier to deport migrants.
Some 7,000 migrants, mostly from Africa, have reached the Canary Islands in the Atlantic Ocean this year alone, after Morocco increased security around the shorter Mediterranean sea crossing to Europe.
But many also drown in their attempts to reach Spanish territory, which they see as a stepping-stone to a better life in Europe.
Mr Faye said the navy was stepping up patrols and was working with the police and para-military gendarmes to stop the migrants.