Spying On Sperm Whales
Wayne Perryman, a marine biologist with NOAA Fisheries, launches an unmanned aircraft into the sky above the South Pacific. Perryman uses aerial drones to get close to sperm whales so that he can study their health and physiology. Photo credit: Moira Brown, New England Aquarium.
A photograph of a sperm whale taken from close range by an aerial drone. Scientists have developed statistical techniques to estimate a whale’s age and weight from straight-down photos such as this. These photos also allow scientists to monitor the health of individual animals by observing how well they’re eating, whether they’ve had run ins with ships or fishing gear, and in the case of females, whether they’re pregnant.
A sperm whale begins its dive. Photo credit: David Csepp, NOAA Fisheries.
New Technology Enables Safe, Non-Invasive Methods for Monitoring the Health and Physiology of Large whales
March 7, 2013
There’s a lot you can tell about a whale from the air. Looking at a straight-down photo, scientists can estimate the age and weight of a whale, how well it’s eating, whether it’s had run ins with ships or fishing gear, and in the case of females, whether they’re pregnant. Scientists have developed these techniques out of necessity: you can’t sedate a whale and then give it a physical the way you would a wolf or a rhino.
But aerial surveys have their limitations. First, they can be expensive. Second, the aircraft has to keep its distance. You can’t be buzzing a whale like a fighter jet coming in on a strafing run. Instead, the aircraft maintains its altitude as scientists use high-powered lenses to get straight-down shots from high up.
But lately, scientists have started to get in close. This week, scientists aboard a research vessel in the South Pacific, off the coast of New Zealand, used aerial drones to collect health data, up close, from sperm whales. These drones are small and relatively quiet. They can hover, swoop in, and collect photos and video from close range, all without disturbing the animal. But as scientists quickly realized, using this technology at sea can be tricky.
The Challenges of Operating Unmanned Aircraft at Sea
Wayne Perryman, a marine biologist out of NOAA’s Southwest Fisheries Science Center, was on the research cruise. Perryman is a pioneer in using aerial surveys for studying marine mammals. He was among the first to adapt military spy cameras for monitoring dolphin populations during the 1980s, when hundreds of thousands of them were dying each year in tuna nets. More recently, Perryman pioneered the use of aerial drones for surveying penguins and leopard seals on land. Now Perryman is taking his unmanned aircraft out to sea.
“There are a lot of challenges in making this jump,” Perryman said by email the other day. “Sometimes the best way to discover the shortcomings of a system is to take it into the new environment and see how it performs.”
In this case, the challenge was in operating the aircraft from a small boat. Perryman had to be in a position to see both the whale and the drone in order to safely maneuver it over the targeted animal. But research vessels are too large to approach whales closely. So Perryman made his final approach in a small tender boat. Launching worked out fine, Perryman said, even in large swells. “But catching the bird from an active deck was a bit like trying to catch a knuckleball bare handed.”
To design and build the aircraft, Perryman teamed up with Don Leroi, an engineer with a company called Aerial Imaging Solutions. The drones are built using relatively inexpensive hardware and consumer-level cameras. After one aircraft had what Perryman described as an “unscheduled flotation test,” he and Leroi quickly built a new model with improved waterproofing around the hull.
Next Step: Sample a Whale’s Plume
During this recent expedition, Perryman and Leroi worked out solutions to the challenges of operating at sea. To solve the problem of the hard landing, for instance, the new model will be designed to splashdown and then be retrieved with a net.
Now that they’ve shaken out the bugs, the next step will be the true groundbreaker. Next time out, Perryman plans to maneuver the aircraft into position above a whale and, when it comes up for air, swoop in above the blowhole to sample the plume. The plume contains epithelial cells, enzymes, and microorganisms. By sampling these, scientists can analyze DNA, measure hormone levels, and get other indications of an animal’s health and physiology.
“If you’re going to manage a population of whales, you need to know more than just how many there are,” Perryman said. “You have to know something about the condition of individuals in the population.” Aerial surveys have long been a standard tool for collecting this information, and for some populations, unmanned aircraft may soon offer a more cost-effective alternative. With his drones, Perryman is taking the whale check-up to a whole new level.
The Sperm Whales of New Zealand Expedition included scientists from the Woods Hole Oceanographic Institution, the New England Aquarium, the New Zealand Whale and Dolphin Trust, and NOAA Fisheries. Perryman’s work with unmanned aircraft is just one of many cool new ideas for non-invasive sampling that scientists worked on during this research cruise. See what else they were up to on the Expedition Blog.