After a long migration, humpback whales are passing through the French island of Reunion to mate or give birth to their young in the warm waters of the Indian Ocean. Around "300 to 400 whales" have been photo-identified by Vanessa Estrade, a veterinary doctor working for the Globice association, and her team. Reunion Island is one of the few places in the world where it is permitted to go into the water with whales. The practice, which is very closely supervised, is based on a passive observation method that is less intrusive for the animals. IMAGES AND SOUNDBITES