 In 1963 he switched his focus to the Atlantic Ocean, participating with Francis Roux in an expedition to the Savage Islands.He then proceeded to study Cory's shearwater in the Madeiras with Alec Zino, a collaboration that has resulted in over eighty publications.Jouanin is recognized as an expert on the Order Procellariiformes and co-wrote the section on those birds in James Lee Peters's Check-list of Birds of the World.