Endangered killer whales in the Strait of Georgia have to shout over constant noise from increasing marine traffic, researchers have discovered. "The noise is virtually continuous during daylight hours and quietens a little bit overnight," Richard Dewey, associate research director on the University of Victoria's VENUS project, said. "In addition to the annoyance of the constant din, [the whales] are likely to have to shout over the engine sounds and listen through the racket to pick out and identify the messages." Tricky tasks, such as the use of broadband clicks to echo-locate fish – the sole diet for resident killer whales – is likely to be extremely difficult when boats and ships are nearby, Dewey said.
VENUS – Victoria Experimental Network Under the Sea – has hydrophones in an underwater network of hubs in the Strait of Georgia and Saanich Inlet. The instruments are connected to researchers around the world, through high-speed communications techniques. It is a challenge sorting out the streams of noise, which also includes the scratchy sounds of creatures such as squat lobsters apparently preening their gills on the hydrophone, Dewey said. "We are picking up both engine noise and vocalization and, although we can't understand whale-speak to say the whales are using different words or different tones in the presence of engine noise, we hope to get that sorted out in the future," he said.
It was expected the Strait of Georgia would be noisy, as it is one of the busiest shipping lanes in the world, but among recent changes is the increase in massive container freighters. "They travel at twice the speed that vessels used to travel at, they use four times as much energy and make four times as much noise in the ocean," Dewey said. One of the – as yet unanswered – research questions is whether the whales can survive increasing noise at the same time as they are coping with shrinking salmon runs and climate change. "Whether the whales and dolphins can adapt is an open question," Dewey said. "Sorting out which part of these changes they are responding to is another part of the challenge."
Resident killer whales, with 87 animals in the three pods, are a major focus for VENUS researchers. Marine mammal specialist John Ford, of the Department of Fisheries and Oceans Pacific Biological Station, is trying to learn and analyse whale language as part of the project. That means sorting out different sounds for echo-location, long-distance calling and intra-pod communication. "Then we will try to find trends that they might have to employ to adapt to this noisy environment," Dewey said. "It is unlikely that they have had long enough to develop an adaptive language, but it is likely they need to yell more than previous generations."
In two weeks, the VENUS hydrophones will be moved from their current location, 170 metres down, to sites at 300 metres depth, which is likely to provide new information, especially as there are more fish at the deeper depth, Dewey said.
For more information, Go to the University of Victoria Venus website
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