Between July 14 and 18, three rescue operations were carried out in the port city of Nouadhibou and 387 people were brought to safety, according to the UN refugee agency UNHCR.
143 people are reported dead or missing from one of the boats that drifted for 25 days at sea, en route from Gambia to Spain. Only 38 were rescued.
In the second rescue operation, 179 people were brought to safety, and in a third, 170 were rescued from a ship where one person had died.
The number of migrants and refugees reaching Europe via the most common routes has fallen significantly this year, while an alarming number of people continue to die at sea, UNHCR warns.
