By Emily Anthes
One day in September, a team of scientists clambered onto a small boat and set out into the Salish Sea, searching for an endangered population of orcas. The Southern Resident killer whales, one of several distinct orca communities that inhabit the Pacific Northwest, can be elusive, so the researchers were delighted to find a small pod of them. But as they drew closer, a putrid smell washed over the boat.
The scientists eyed one another with suspicion before it dawned on them: The odor was coming from the clouds of mist that the whales were expelling from their blowholes. “Everybody is allowed to have bad breath every now and then, but this was not just bad breath,” said Dr. Hendrik Nollens, vice president for wildlife health at the San Diego Zoo Wildlife Alliance, who was on the boat. “There was something going on.”
Fetid breath can be a sign of illness or infection, but the cause could have been anything from a tooth abscess to a life-threatening case of pneumonia. Fortunately, the scientists were armed with an experimental diagnostic tool: a breath-collection drone. The technology — essentially a flying petri dish that could be steered into an orca’s plume — was still under development, but it was about to face an unexpected, real-world test. “We were concerned,” Nollens said, “and so we launched our drone.”
It’s not easy to perform a veterinary exam on a wild, multiton marine mammal that might surface for only seconds at a time. But for the past five years, a team of veterinarians, marine biologists and engineers has been developing tools to do just that. Their goal is to perform regular, remote health assessments on each of the Southern Residents — and, if necessary, to intervene with personalized medical care.
It’s an unconventional approach to conservation, which typically aims to shore up the health of populations rather than individual animals. But the Southern Residents, which were listed as endangered in 2005, are in serious trouble, threatened by pollution, boat traffic and plummeting stocks of wild salmon, their preferred food source. Despite continuing conservation efforts, the population is about 75 whales.
“We’re in a dire, dire situation,” said Dr. Joe Gaydos, science director of the SeaDoc Society, a marine conservation program at the University of California, Davis, School of Veterinary Medicine. “We’re at that point where the health of every single individual is important.”
An ailing whale
That became painfully apparent five years ago, when another sickly Southern Resident known as J50 set the project into motion.
When she was born in 2014, J50 was a sign of hope; it had been more than two years since the last successful birth in the Southern Resident population. The calf was covered in scars, earning her the nickname Scarlet, but she seemed healthy and vigorous, becoming known for her playful behavior. “Everybody loved her,” Gaydos said.
Over the years that followed, the National Oceanic and Atmospheric Administration worked with a nonprofit organization called SeaLife Response, Rehabilitation and Research to keep tabs on the Southern Residents, using aerial photography to monitor the whales’ size and condition. In the summer of 2018, the photographs revealed that Scarlet had become shockingly skinny. Behavioral observations suggested that she was weak, sometimes falling far behind her pod.
NOAA assembled an emergency response team, working with many organizations and experts including Gaydos and Nollens, then a veterinarian at SeaWorld.
The scientists looked for signs of a respiratory infection, a common and dangerous ailment in whales, by attaching a petri dish to a long pole and holding it above Scarlet’s blowhole when she exhaled. They scooped fecal samples out of the water, analyzing them for parasites.
They found no clear answers, leaving the team with a stark choice: They could try to do something, or they could watch Scarlet waste away. “Do we just have to sit here and watch this poor whale die?” Gaydos recalled thinking.
So they tried the few treatments they had, using a dart gun to administer antibiotics and depositing live salmon in the starving whale’s path.
Scarlet continued to deteriorate, and in September, she disappeared. After an intensive, fruitless search, Scarlet was declared dead.
It was an enormous loss not only for the people who had come to love Scarlet but also for the Southern Resident population, which desperately needed young females to survive and reproduce. Other young orcas had died in recent years, too. “Trying to understand why they’re going out of population prematurely has been a big challenge,” said Brad Hanson, a wildlife biologist at NOAA’s Northwest Fisheries Science Center.
Experts had already been discussing the need to develop techniques to diagnose, and potentially treat, sick whales, but Scarlet’s death made that pursuit feel urgent. “We realized, wow, we didn’t have a lot of tools in the toolbox,” Gaydos said. “We were doing, like, Civil War medicine.”
Drone development
For the past few years, Hanson, Gaydos, Nollens and their colleagues have been experimenting with a variety of techniques, including using infrared cameras to measure the whales’ body temperatures and directional microphones to record their breathing.
And they have gone all-in on developing a breath-collection drone. The respiratory droplets that the whales exhale are a biological gold mine, allowing scientists to search for viruses and abnormal cells. But a petri dish on a pole was not going to cut it.
Other researchers had used drones to collect breath samples from large whales, such as humpbacks, which produce big plumes. Orca exhalations are smaller and harder to collect. But using computational modeling, experts in conservation technology at the San Diego Zoo Wildlife Alliance discovered that if they mounted a petri dish on a drone in the right place, air currents generated by the propellers would help funnel the respiratory droplets onto the dish.
The team tested their prototypes and refined their approach with captive orcas at SeaWorld and more robust wild whales before sending the drones buzzing over the Southern Residents. “We have developed the techniques to be able to do this without regularly spooking the animals,” Hanson said.
The scientists know that they can’t save the Southern Residents through veterinary interventions alone, but they hope to buy the whales more time while broader conservation efforts continue.
“When we started out, it was a pretty far-fetched idea to say, ‘We’re going to do veterinary exams on wild, free-swimming orcas, and they won’t even know we’re doing it,’” Nollens said. “It’s not far-fetched anymore.”