Scientists Use Drones To Track Whales Off California Coast
Thursday, March 19, 2015
Southern California's whale-watching industry is reporting a busier than usual season along the coast this year. Good weather gets some of the credit, but researchers are also trying to figure out why the cetaceans appear to be doing well.
Audrey Evans only needs a quick glance at the ocean to find gray whales.
"When they exhale there's a little bit of the water vapor that comes into the air," Evans said. "For a gray whale its about 15 feet high."
Evans says whale spouts can be seen from boats and from land.
"And because they have two openings at the top of their head, for blowholes, it creates a heart shaped blow. So the blow is the first thing that we look for," Evans said.
The Birch Aquarium education specialist said whale watchers have spotted more than 700 whales since fall, which is 100 more than a year ago, and this whale migration season still has two months to go.
The migration has resulted in a lot of sightings, but researcher Wayne Perryman, a biologist at the Southwest Fisheries Science Center, said the reason might be easily explained.
"Everyone was going, 'my gosh we're seeing so many gray whales,'" Perryman said. "Part of that was because the weather was so calm you could see them forever."
Perryman has studied cetaceans since the 1970s and gray whales since the 1980s. The overall population is holding steady at about 20,000. But Perryman said there are a lot of young whales around these days.
"We've seen really good reproductive levels the last four years. Lots of calves. Over 1,000 calves migrating northbound," Perryman said.
A shifting environment may be the reason. Gray whales feed in the arctic and then travel south to Mexico to give birth. Perryman said global warming may be changing the ocean ecosystem by extending how long the whales can feed up north.
"Gray whales are arctic whales. That's where they make a living," Perryman said. "And the arctic is changing very rapidly. So by watching gray whales, we get kind of a window into what's happening in the arctic."
That window is about to open a much wider.
Perryman and fellow Southwest Fisheries Science Center researcher John Durban are pioneering the use of drones to track baleen whales. The team's small hexacopter has already captured amazing images of killer whales of the coast of Canada.
"After the first flight, when we brought the hexacopter and downloaded the images and I was blown away," Durban said. "I didn't realize how much better they would be than what we had before."
The pictures are so good, that researchers can use the photos to spot general health conditions, pregnancy, and even markings unique to individuals.
The hexacopter hovers at about 100 feet and that offers dramatically better pictures than what researchers used to get from fixed wing aircraft. Those small planes typically took pictures from 750 feet.
Durban said the hexacopter is remarkably unobtrusive.
"We can fly the small hexacopter over them. Measure them. Take images of them. Without them even knowing we're there. There's not even a boat in the water," Dunham said.
The pictures are a revelation but researcher Wayne Perryman wants to use the drones to collect biological samples.
It is not a new idea. Researchers have tried using small boats to get near swimming whales. Scientists would reach out with long poles. On the end of the extension was a collector that they held near the animal's blowhole. The idea was to snag a sample when the whale exhales.
"They have a hell of a time doing it and its not very safe," Perryman said. "Because sometimes the whales take offense to this sort of thing and we've had people, whales lash out at them and that can go poorly."
The hexacopter changes the equation, according to Perryman, because the small craft can hover just a few feet over the ocean.
"So we can put the drone where we want it and just follow the back of the whale, because we're getting live video, and just slide up its back," Perryman said. "When those big nare's open up and that breath comes out. We can be right over the top."
Capture the blow and there is a wealth of information available to researchers.
"If we can sample the blow of a whale, we can capture the epithelial cells. So we can get DNA. We can tell who they are," Perryman said. "We can tell what sex they are. If they're stressed in a nutritive way. If they're too skinny, we can look at hormone levels in that breath and get a scale of how skinny they really are."
Perryman and Durban plan to photograph gray whales in May as the cetaceans move up the central California Coastline. If they succeed in collecting biological samples, the researchers hope to learn more about the whales and the environment they rely on.
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