Oil and gas companies looking for deposits offshore have touted their equipment as environmentally friendly. However, new research suggests that blue whales are having a hard time hearing each other over the seismic blasting that the search entails.
Research has discovered that whales forced to compete with the seismic testing work, which involves bouncing sound waves off the sea bed, markedly increase the number of times they repeat the same calls [The Times].
The study, published in
Biology Letters, was conducted in Canada's St. Lawrence Estuary, and is the first report of whales increasing their calls in response to underwater noise. Researchers believe that the whales are repeating the calls simply because other whales can't hear them, and they're having trouble gathering to feed and mate. Blue whales' numbers have dwindled to somewhere between 5,000 and 10,000, so any disruption in their social behaviors is not helpful for a population that is looking to rebound to pre-whaling numbers.
The sharp sounds of seismic surveys are a particular concern. Engineers use very sharp, very loud bangs because these produce the clearest images of geological structures below the sea floor [BBC News]
.
In a similar case in Russian waters, an energy consortium decided to suspend seismic blasting after viewing evidence that their work was driving the endangered western gray whale (of which there are only about 130 left) away from its summer feeding spot. There has been no word on the future status of the blasting in the St. Lawrence Estuary.
Related Content: 80beats: Blue Whales on the Move: Good News or Bad Sign? 80beats: Sonar Damage to Dolphins’ Hearing Is Akin to the “Rock-Concert Effect” 80beats: Navy 1, Whales 0: Supreme Court Allows Navy’s Sonar Exercises 80beats: Cacophony in the Oceans May Confuse Whales and Drown Out Their Songs
Image: flickr / Seabass London
