Humpback whales rely on complex song and social communication that is increasingly disrupted by anthropogenic ocean noise from shipping, sonar, and seismic surveys, causing significant welfare harm.
Ocean noise pollution creates chronic stress for humpback whales that is measurable but invisible to casual observation. Whales navigating through shipping lanes experience sustained noise levels that mask communication over distances that previously allowed contact between pods kilometres apart. This communication disruption affects mother-calf contact calls, male-female acoustic signalling during breeding, and the feeding coordination sounds that allow groups to cooperate around prey patches. Physiological stress responses to chronic noise exposure increase cortisol, suppress immune function, and reduce reproductive success — effects documented in baleen whales studied in high-shipping-traffic areas compared to lower-noise zones. Military sonar causes acute, severe responses: whales attempt to surface rapidly from depth to escape the noise, causing decompression injury in extreme cases. Shipping speed reductions in whale habitat areas offer an immediate, practical mitigation — slower ships produce dramatically less noise and also reduce ship-strike mortality.