From an article at Scientific American about the effects of manmade noise on the whale's environment -
Of greatest concern are low-frequency sounds that travel long distances in the ocean. Ship propellers and motors, for instance, produce sound at low frequencies, as does seismic activity. These profound, loud noises reverberate in the deep ocean and can effectively mask or block vital whale communication. In Cape Cod Bay, man-made noise has reduced right whales' acoustic habitat by as much as 80 percent, says Chris Clark, director of Cornell University's Bioacoustics Research Program.More at the link.
To better understand these underwater acoustics, Clark and his colleagues have developed graphic animations that show the acoustic habitat as experienced by whales. Using data collected by seafloor sound monitors, the scientists can map the locations of whales and measure their sounds, along with anthropogenic sounds. The resulting animations vividly depict how the noise from human activities physically obstructs and reduces whales' habitat, interfering with what Clark calls the animals' "communication space."
Within the lifetime of the whales that Clark has been observing (some of the right whales he studies can live for 70 years), anthropogenic noise has increased dramatically. "When these long-lived species were kids and teens, the world was normal," says Clark. "Now their background noise has gone up by three orders of magnitude."