WHALES might be suffering hearing loss due to noise generated by engines of tourist boats, ships, and large tankers, according to Peter M Scheifele, a bioacoustic researcher at the University of Connecticut, USA . Whale-watching has become a popular tourist attraction across the world. Tourists are taken in boats to see whales from a distance of a few to hundred metres. This is a good source of income for tour operators. But the whales are exposed to high levels of noise generated by the engines of boats that often crowd around one or two animals. This has caused concern among researchers who believe that in the long run, such activities might affect the hearing capability of whales.
Marine mammals depend on sound waves travelling through water for navigation, avoiding predators, and finding mates. Scheifele and other researchers are planning a project to determine the effect of such underwater noise generated by engine driven vessels over the last century, most of which is being caused by tankers and merchant ships. A lot of fishing boats carrying tourists generate a lot of noise and at a close range, which according to Scheifele is conditioning animals not to be afraid of ships. According to Whale and Dolphin Conservation Society, Bath, UK , 5.4 million people in 65 countries went whale-watching in 1994. Two-thirds in the US alone.
Recognising the potential for harm to the whales, National Marine Fisheries Service of the US has set guidelines to protect the animals. It says that boats should stay more than 90 m away from the whales and should not charge and travel parallel to the whales.
A project is scheduled to study the effect of noise on whales, but simple observations would not be fruitful because it is quite likely that — like humans — whales could endure repeated loud sounds without realising that their hearing is being damaged, says Scheifele.