A method and marine seismic processing system including an interface for receiving recorded data, wherein the recorded data includes seismic data and bio-acoustic data; a seismic data processor for estimating a source signature from the recorded data, wherein the source signature is associated with a seismic source that emits seismic waves in water during a seismic survey; and a bio-acoustic processor that estimates a presence of a mammal generating the bio-acoustic data, based on a processed signal obtained by removing the source signature from the recorded data.