Passive acoustic monitoring (PAM) of marine mammals was performed on board of the Geco Triton vessel in the Block 3, adjudicated to YPF by ANCAP. Its purpose consisted in reducing the risk of injuries and/or disturbances of the marine mammals living in the area due to the offshore seismic activities. The activities are carried out by staff trained in acoustic detection. This staff is also responsible for the implementation of the mitigation measures and for advising the vessel´s crew on the application of international protocols in case of detection of any marine mammal. These technicians have a JNCC certificate and BIOSET security courses.