Using Drones to Tag Whales
Using Drones to Tag Whales
Dropping sensors on whales from a drone may replace the old method of using a long pole to attach a sensor on their skin.
The technique marine biologists use to tag whales sounds like something out of Melville: A crew separates from the larger ship on a 20-foot whaleboat, approaches the spot in the sea where they’ve recently seen a spout, and aims a tool at the great beast when it surfaces again.
“You approach the whale sort of slowly, but closely, with the tag at the end of a long pole,” said Lisa Conger, a research fish biologist for the National Oceanic and Atmospheric Administration. “You basically sort of slap that on to the whale; ‘slap’ is probably not a good word, but you do need a little bit of energy to get the suction cups to stick.”
The method is time-consuming, dangerous for the scientists on board, and can scare whales off of letting a boat of researchers get that close to them again. It also is antiquated. There’s now another way to tag a whale using drones.
Conger is the chief scientist on the NOAA Northeast Fisheries Science Center’s North Atlantic right whale cruise. She teamed up with the Ocean Alliance, including its crack drone flyer Chris Zadra, to drop tags on whales from above. The rig they came up with is remarkably simple. The drone holds a 3D-printed four-pronged arrowhead of sorts that stabilizes the drone’s flight, holds the tags, and gives them enough weight to stick when they land.
“They call it a robot, but there’s nothing robotic about it,” said Conger.
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The drone is controlled from a boat far from the whale that’s being targeted. Once the drone has been maneuvered over the mammal, the pilot matches its speed in the water and then, when the moment is right and there’s exposed whale skin, the drone releases the robot. It plops the suction cups on the whale and falls away to be retrieved later.
Zadra tested the system—and his piloting and whale-following skills—on a “gel-equipped” surfboard towed by a dingy. Once he had confidence in the apparatus and his own technique, the team took both out on an eight-day field test where, out of 29 attempts, 21 tags stuck where they wanted them.
On that trip, and others since, the drone is launched out of a boat similar in size to the ones used with the stick-and-slap method. But on a more recent expedition the team hit a bit of weather, 80 miles offshore, that was too rough for the smaller boat. So they piloted the drone from the ship without mishap and also managed to retrieve the robot.
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The whales don’t seem bothered by whatever boat from which the drone is flown. “They can probably hear it,” said Conger. “But they have a lot of things in the natural world that fly over their heads.” Zadra has reported he’s seen whales roll over and look up at the drone, but they never tried to evade it.
The actual tags that the drone drops are the same as the ones used previously. They collect data on the fine-scale movements of whales and fall off in a couple of days. Not having to approach with a boat will mean a huge uptick in data collection at a time when whales are having to alter their behaviors to survive.
The right whale, which Conger’s team was tagging on this last trip, has a population now that is only in the 300s. “They are changing up their habitat use all over the place. And so we’re trying to get a handle on exactly how they're using the habitats that they’re in,” she said. “Dropping the tags with the drone is incredible. A big game changer.”
Michael Abrams is a technology writer in Westfield, N.J.