More than 60 migrants are feared dead after a Spanish fishing vessel off the Atlantic island of Cape Verde rescued a boat that started with more than 100 aboard, authorities said on Thursday.

Seven dead bodies were found on the boat, while an estimated 56 people are missing at sea and presumed dead, the International Organisation for Migration said. According to Senegal’s foreign affairs ministry, 38 survivors were rescued earlier in the week near Cape Verde, about 620 km off the coast of West Africa from the large fishing boat (called a pirogue) which had left Senegal on July 10.