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Blue Whales Suffering From Hearing Loss

By Kevin Jess     Sep 23, 2009 in Environment
New research shows that blue whales have to 'sing' and 'chatter' longer and more often in order to compete with noise from ships, oil drilling and other forms of noise pollution.
In a report by the Telegraph the new research has found that noise has caused other changes as well, in particular behavioural changes.
In the past few years hi-tech sonar by ships, the noise of propellers, sea-floor drilling, low-frequency radio transmissions and seismic surveys, have been creating a lot of noise in the ocean. But this study published in Biology Letters, shows the first concrete proof that blue whales change their calling behaviour when exposed to sounds from seismic surveys.
The Telegraph also reported on zoologist Lucia Di Iorio, of the University of Zurich who said upon analyzing recorded songs of blue whales during seismic surveying, "We found that blue whales called consistently more on seismic exploration days than on non-exploration days as well as during periods within a seismic survey day when the sparker was operating." She added, "This increase was observed for the discrete, audible calls that are emitted during social encounters and feeding."
Blue whales grow to be up to 32.9 metres (108 ft) in length and 172 metric tons (190 short tons) or more in weight, it is the largest animal ever known to have existed. Blue Whales were abundant in nearly all the oceans until the beginning of the twentieth century. For over 40 years, they were hunted almost to extinction by whalers until they were protected by the international community in 1966. A 2002 report estimated there were 5,000 to 12,000 Blue Whales worldwide.
In Canada, environmental law organization Ecojustice, which is representing several groups opposed to seismic surveying has filed an injunction application in Federal Court in Ottawa to stop seismic soundings from a U.S. research vessel in an area used by endangered whales reports CBC News.
Columbia University researchers are mapping the tectonic plates in the area just off the west coast of Canada by sending "180-decibel blasts into the water every couple of minutes, which would create a noise as loud as an army artillery piece going off," says Ecojustice.
Ecojustice feels that this would threaten endangered blue whales who are in a protected Canadian marine area reports the CBC.
But in Federal Court the injunction was rejected as the researchers had reduced the maximum sound level of seismic charges from 180 to 160 decibels making the injunction application outdated.
In an interview with CBC News Ecojustice staff lawyer Lara Tessaro said, "In Canada, it is illegal to disturb and harass whales and dolphins. The reason marine protected areas exist is to keep harmful activities from occurring in special areas that protect the animals living there, including endangered species like blue whales."
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