According to Senegal’s foreign affairs ministry, 38 survivors were rescued earlier in the week near Cape Verde, about 620 kilometers (385 miles) off the coast of West Africa.
The Spanish migration advocacy group Walking Borders said the vessel was a large fishing boat, called a pirogue, which had left Senegal on July 10.
Families in Fass Boye, a seaside town 145 kilometers (90 miles) north of the capital Dakar, had reached out to Walking Borders on July 20 after 10 days without hearing from loved ones on the boat, group founder Helena Maleno Garzón said.
The Spanish vessel was unable to tow the fishing boat and took the survivors on board, according to a Cape Verde police statement on Facebook.
The route from West Africa to Spain is one of the world’s most dangerous, yet the number of migrants leaving from Senegal on rickety wooden boats has surged over the past year.
Worsening youth unemployment, political unrest, violence by armed groups, and climate change push migrants across West Africa to risk their lives on overcrowded boats.