1. The rarest seal and the world's most endangered pinniped species, the Mediterranean monk seal (Monachus monachus), has a small and isolated population in the Madeira Archipelago (Portugal). This species tends to be extremely wary of humans and, therefore, very difficult to approach and study. 2. Passive acoustic monitoring (PAM) is a non-invasive, cost-effective tool that can be a valuable complement for the...