Hundreds of migrants missing off West Africa; boats remain unaccounted for despite rescue efforts

Three migrant boats with over 300 people went missing off the coast of West Africa in late June.
Spanish coastguard rescued 86 migrants but 3 boats remain missing along the Atlantic route to the Canary Islands.
Migrant aid group Walking Borders disputes Senegalese authorities' claims that missing boats were found.
A boat found in distress off Senegal rescued 50 people but 90 are still missing, with 7 confirmed dead.
The Canary Islands have become a major destination for migrants risking the dangerous Atlantic crossing to reach Europe.