Predicting the biological component of ocean soundscapes

The ocean can be a noisy place. Sound travels extremely well, particularly at lower frequencies (below 1 kHz) and sound sources from great distances can contribute to the local soundscape. The soundscape is defined as the spectral and spatial characteristics of the sound field from all sources. Emphasis has been primarily on “noise modeling” for Anti-submarine warfare (ASW) performance and modeling and more recently on sound exposure to marine mammals, for conservation purposes. For these reasons, the primary sources of interest have been wind and ships, seismic exploration, and pile driving. Yet with animals using sound for many things (communication, hunting and possibly local environmental awareness and navigation), there is a rich contribution to the soundscape from most marine animals. In this work, we present a modeling approach to simulate the spectral and spatial contribution of marine mammals into the ocean soundscape. The model includes state-of-the-art knowledge of animal distributions, call behavior and rates (inter-click intervals) and characteristics. Each of these is the result of entire communities of researchers. We present a simulated soundscape (spectrogram and bearing time record) that includes wind, ships, Minke, Fin, and Sei whales in the Gulf of Maine.