Like humans, whales 'shout louder' to overcome noise

Washington, July 7 (ANI): Just like humans, North American right whales increasing the volume of their calls as environmental noise increases - a trend that scientists say could endanger the species further.

This noise might affect the whales' communication range for feeding or mating will shrink and stress levels on individual animals may rise.

"Right whale upcalls are used extensively for passive acoustic monitoring in conservation efforts to protect this endangered species," said Susan Parks, assistant professor of acoustics and research associate, Applied Research Laboratory, Penn State.

An upcall begins low and rises in pitch. It is the most frequent call produced by right whales when they are alone or in the process of joining with other whales.

Parks and her colleagues, Mark Johnson and Peter L. Tyack, Woods Hole Oceanographic Institution and Douglas Nowacek, Duke University believe that much of the increase in background ocean noise in right whale habitat is believed to be due to commercial shipping.

"Ocean sound levels will probably continue to increase due to human activities and there is a physical limit to the maximum source level that an animal can produce," said Parks.

The study appears in today's (July 6) issue of Biology Letters. (ANI)