DAKAR, Senegal — Migrant deaths along the Atlantic route from West Africa to Spain's Canary Islands reached a record high last month with 379 lives lost, the International Organization for Migration said Friday. 

Those deaths account for nearly half the total number of casualties for all of 2021 — 735 adults and 50 children — according to the United Nations agency's Missing Migrants Project. 

More than 9,300 people have arrived in the Canary Islands by sea in the first eight months of 2021, a significant increase from 2020 when 3,933 arrived. The Atlantic route is one of the most dangerous sea crossings to Europe.

The COVID-19 pandemic and the measures taken to counter it have added to the many other reasons for people to risk migrating by sea: conflict, poverty and limited legal migration channels. 

Many survivors describe conditions that suggest the voyage from West African shores is becoming more risky, with more people cramming aboard ships that often run out of gas, food and water. 

Some told the IOM of desperate situations where the bodies of people who died on boats were thrown overboard, or passengers went mad from lack of food and water and leapt into the sea. The remains of some have been brought up by fishing vessels. 

"Invisible shipwrecks, in which there are no survivors, are believed to be frequent occurrences on this route but are nearly impossible to verify," said Frank Laczko, Director of the IOM's Global Migration Data Analysis Center. "The lack of concerted efforts to recover migrant remains on this and all routes means that hundreds of families are left bereaved."

It's likely the death toll for those making this difficult journey is significantly higher, Laczko said. 

The Spanish civil society organization Caminando Fronteras estimates that 36 boats have disappeared without a trace in the first six months of 2021 along the Atlantic route. 

"Ending this senseless loss of life on all maritime migration routes to Europe requires a comprehensive response, enhanced state-led search and rescue capacities and pathways for safe, orderly and regular migration," Laczko said.