Dozens are feared dead after a boat carrying migrants that departed Gambia last month was found by authorities drifting off Spain’s Canary Islands late Wednesday.

Helena Maleno, the head of the Spanish NGO Caminando Fronteras (Walking Borders), said that 83 of the boat’s 127 passengers had died, with four women and a baby among the victims. The passengers had embarked on the journey from the West African nation 27 days ago, she said.

Spain’s Maritime Safety and Rescue Society, also known as SASEMAR, told CNN that they had rescued a “makeshift boat” on Wednesday night that was drifting 65 nautical miles southwest of Arguineguín, a town on the south coast of Gran Canaria.

Forty-four people were rescued from the boat, SASEMAR told CNN, including three people who were in critical condition and airlifted to a local hospital. SASEMAR said that they were unable to retrieve the bodies of five other people, saying adverse weather conditions hindered the operation.

All of the people found on board were men from sub-Saharan Africa, according to the maritime authority, which said it could not confirm how many passengers the boat was carrying when it left Gambia.