Living on Earth's Cynthia Graber reports on a new technique that scientists hope will help ships avoid colliding with northern right whales.
CURWOOD: There are only about 300 northern right whales left in the world. And one of the biggest threats to their continued existence is collision with passing vessels in the busy shipping lanes of the North Atlantic. In Halifax, Nova Scotia, researchers are hoping to use sound waves to help prevent these often fatal encounters. Living On Earth's Cynthia Graber reports.
GRABER: The ocean is a noisy place. It's filled with the rumblings of boats, the calls of marine creatures, and the din of churning water. But sometimes, amidst the white noise of the sea, a sound stands out.
GRABER: That's a northern right whale calling out near the well-traveled shipping lanes in the Bay of Fundy, between Maine, Nova Scotia, and New Brunswick.
[SOUNDS OF SEA]
LAURINOLLI: The first sound there was sort of a higher pitched-- sort of, we might call, like, a crying sound.
GRABER: Marjo Laurinolli is a graduate student at Dalhousie University in Halifax, Nova Scotia.
LAURINOLLI: And we heard a couple loud, banging noises. We've been designating those as, we're calling them gunshot sounds. We don't really know how they're producing them. They could be from slapping a body part on the water or a vocal sound; we don't know that yet. And then, there was some really low sounding moaning and groaning sort of sounds.
GRABER: Laurinolli is part of a team trying to use these sounds to pinpoint whale locations in the open ocean. Alex Hay oversees the project.
HAY: The idea was that if we deployed an array of hydrophones and used those hydrophones to detect right whale sound, that we would be able to locate them.
GRABER: And once the whales are located, their coordinates can be sent to ships to help them avoid hitting the animals. Hay says the system can work because sound travels through water at a given speed.
HAY: Therefore, if you have hydrophones that are separated by several miles, the sounds will arrive at different times.
GRABER: So, using a series of hydrophones-- or underwater microphones-- and marking the time each one picks up a whale sound, scientists can figure out where the whale is. But it's tricky science. Sound changes speed with water temperature. In addition, some sound waves can be absorbed or reflected, depending on the ocean floor and surface.
Researchers have had to develop computer programs to account for these variables. So far, Hay says, the results are promising. They've been able to pinpoint a whale's location to within 300 feet within a range of six miles.
HAY: It's been easier than we thought. So that's been the most rewarding thing.
GRABER: A team from Cornell University has also been testing this whale detection technique off the coast of Massachusetts. They've reported similar success, but the system would be expensive to operate. You'd need a computer station in the ocean to recognize whale sounds. Then you would have to transmit the information down a cable to a control center and relay it to ships. But this high tech traffic control network alone won't save the right whale, according to Scott Kraus, a researcher with the New England Aquarium.
KRAUS: Because of the human causes of mortality and the lack of increase in reproduction, the population does appear to be on a knife edge of survival. My guess is that it's going to be much more complicated; that we're going to end up with some complicated mix of technology and basic management strategies-- either closures or rerouting ships or something like that-- that's going to lead to the survival of the species.
GRABER: Scientists hope that the whistles, moans and pops of the whales might help provide one more technological tool for that mix. For Living On Earth, I'm Cynthia Graber.
[WHALE SOUNDS FADE]
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