The boat is believed to have departed Senegal with more than 100 migrants on board in early July.

It was found with 38 survivors and several dead on board near the Atlantic island, authorities and migrant advocates have said.

Senegal's Foreign Affairs Ministry said the boat was discovered on Tuesday by the coast guard in Cape Verde, about 385 miles off the coast of West Africa.

It is not immediately clear when the incident occurred, nor the full extent of the casualties.

The Spanish migration advocacy group Walking Borders said the vessel was a large fishing boat, called a pirogue, which had left Senegal on 10 July with more than 100 migrants on board.

Families in Fass Boye, a seaside town 90 miles north of the capital Dakar, had reached out to Walking Borders on 20 July after 10 days without hearing from loved ones on the boat, group founder Helena Maleno Garzon said.

Cheikh Awa Boye, president of the local fishermen's association, said he has two nephews among the missing.

"They wanted to go to Spain," Mr Boye said.

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.

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Nearly 1,000 migrants died while trying to reach Spain by sea in the first six months of 2023, the Walking Borders group says.

On 7 August, the Moroccan navy recovered the bodies of five Senegalese migrants and rescued 189 others after their boat capsized off the coast of Western Sahara.