捕鯨とクジラ保護

Falling on Deaf Ears?




Man-made noise in the world's oceans is a serious form of underwater pollution that can cause behavioral disturbances in whales, physical injury and even death. The ocean is a highly acoustic environment where sound travels five times further than in the air. Whales use their sensitive hearing and unique vocalizations to locate and communicate with each other, navigate, find food, and avoid predators. As a result, even seemingly minor human-generated noise can be like an acoustic assault on these sensitive creatures.

Though noise is a recognized form of pollution, ocean noise remains largely unregulated and attempts to reduce harm to marine life have generally been inadequate and/or ineffective.

The most pervasive manmade ocean noise is daily ship traffic. Shipping creates noise at the same frequency ranges that are used by many species of whales, particularly the large baleen whales. Prolonged exposure to ship noise may cause whales to abandon critical habitat, perhaps affecting healthy feeding patterns or reproduction.

Underwater sound is also generated by offshore industrial development such as seismic surveys, pipeline and platform construction, and drilling. Seismic survey noise has been demonstrated to result in displacement of whales and reduction in whale vocalizations. Intensive sound waves from explosions can also cause internal damage to whales. Whether impacting migrating paths, feeding, breeding or calving grounds, industrial developments are degrading critical whale habitat and impacting normal whale behavior in habitats around the world.

Active military sonar is one deadly form of ocean noise. It has been found to kill whales, and can also alter the singing of humpback whales, disrupts the feeding of orcas and causes porpoises and other species to panic and flee. Among the most dramatic and visible impacts of high-intensity sonar are mass whale strandings.