My master thesis (conducted with the Bottlenose Dolphin Research Institute and supervised by Prof. Klaus Zuberbühler) aims to have a better understanding of the diving behaviour of blue whales (Balaenoptera musculus) and fin whales (Balaenoptera physalus) in the Atlantic Ocean. More specifically, we want to assess the impact of marine traffic density and ship proximity on the dive duration of these two species of whales, as well as the effects of the feeding behaviour and diving types observed. The study could bring new insights on the anthropogenic impact on cetaceans, and help adapting conservation measures. I am particularly interested by this research area because of the concrete measures it can brings for the conservation of endangered mammals species, marine or terrestrial.