Monday, May 20

These veterinarians make home visits to killer whales

One day last September, a group of scientists climbed into a small boat and set out into the Salish Sea, searching for an endangered population of killer whales. Southern resident killer whales, one of several distinct orca communities that populate the Pacific Northwest, can be elusive, so researchers were happy to find a small pod of them. But as they approached, a putrid odor filled the boat.

The scientists looked at each other suspiciously before they realized it: The smell was coming from the clouds of mist that the whales were expelling from their blowholes. “Everyone is allowed to have bad breath from time to time, but it wasn’t just bad breath,” said Dr. Hendrik Nollens, vice president of wildlife health for the San Diego Zoo Wildlife Alliance, who was on the boat. “Something was happening.”

Foul breath can be a sign of illness or infection, but the cause could be anything from an abscessed tooth to a life-threatening case of pneumonia. Luckily, the scientists were armed with an experimental diagnostic tool: a breath-collecting drone. The technology – essentially a flying Petri dish that could be directed into an orca’s plume – was still in development, but was about to face an unexpected real-world test. “We were worried,” Dr. Nollens said, “and so we launched our drone.”

It is not easy to perform a veterinary examination on a multi-ton wild marine mammal that may only surface for a few seconds at a time. But over the past five years, a team of veterinarians, marine biologists and engineers have developed tools to do just that. Their goal is to perform regular, remote health assessments on each of the South’s residents and, if necessary, intervene with personalized medical care.

It is an unconventional approach to conservation, which typically aims to support the health of populations rather than individual animals. But the southern residents, who were listed as endangered in 2005, they are in dire straits, threatened by pollution, shipping traffic and the collapse of wild salmon stocks, their preferred food source. Despite ongoing conservation efforts, the population is around 75 whales.

“We’re in a terrible, terrible situation,” said Dr. Joe Gaydos, scientific director of the SeaDoc Society, a marine conservation program at the School of Veterinary Medicine at the University of California, Davis. “We are at that point where the health of every single individual is important.”

This became painfully evident five years ago, when another sickly Southern resident known as J50 started the project.

When it was born in 2014, J50 was a sign of hope; more than two years had passed since the last successful birth in the southern population. The calf she was covered in scars, which earned her the nickname Scarlet, but she appeared healthy and vigorous, becoming known for her playful behavior. “Everyone loved her,” Dr. Gaydos said.

In the years that followed, the National Oceanic and Atmospheric Administration, or NOAA, partnered with a nonprofit called SeaLife Response, Rehabilitation and Research to keep an eye on the southern residents, using aerial photography to track the size and conditions of the whales. In the summer of 2018, photographs revealed that Scarlet had become incredibly thin. 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 Dr. Gaydos of the SeaDoc Society and Dr. Nollens, then SeaWorld’s veterinarian.

The scientists looked for signs of a respiratory infection, a common and dangerous disease in whales, by attaching a petri dish to a long pole and holding it over Scarlet’s blowhole as she exhaled. They collected fecal samples from the water, analyzing them for parasites.

They found no clear answers, leaving the team with a difficult choice: They could try to do something, or they could watch Scarlet waste away. “Should we just sit here and watch this poor whale die?” Dr. Gaydos recalled thinking.

So they tried the few treatments available to them, using a dart gun to administer antibiotics and depositing live salmon in the path of the hungry whale.

Scarlet continued to get worse and passed away in September. After an intense and fruitless search, Scarlet was pronounced dead.

It was a huge loss not only to the people who had come to love Scarlet, but also to the population living in the South, who desperately needed young females to survive and reproduce. Other young orcas had also died in recent years. “Trying to understand why they are disappearing prematurely from the population has been a big challenge,” said Brad Hanson, a wildlife biologist at NOAA’s Northwest Fisheries Science Center.

Experts had previously discussed the need to develop techniques to diagnose and potentially treat sick whales, but Scarlet’s death has made this research urgent. “We realized, wow, we didn’t have a lot of tools available,” Dr. Gaydos said. “We were doing, for example, Civil War medicine.”

In recent years, Dr. Hanson, Dr. Gaydos, Dr. Nollens and their colleagues have experimented with a variety of techniques, including using infrared cameras to measure the whales’ body temperatures and directional microphones to record their breathing.

And they are fully committed to developing a breath collection drone. Respiratory droplets exhaled by whales are a biological gold mine, allowing scientists to search for pathogens and abnormal cells. But a petri dish on a pole wouldn’t have sufficed.

Other researchers had used drones to collect breath samples from large whales, such as humpback whales, which produce large plumes. Orca exhalations are smaller and more difficult to collect. But using computational modeling, conservation technology experts at the San Diego Zoo Wildlife Alliance found that if they mounted a petri dish on a drone in the right place, the air currents generated by the propellers would help channel the droplets. respiratory systems on the capsule.

The team tested their prototypes and refined their approach with captive orcas at SeaWorld and more robust wild whales before sending the drones to buzz the southern residents. “We’ve developed the techniques to be able to do this without regularly scaring the animals,” Dr. Hanson said.

However, sample collection proved challenging. The drone pilots, who were trained professionals, had to launch the machines from a small boat hurtling out to sea, predict where a swimming whale would surface, maneuver the drone into position before the respiratory droplets disappeared, and then bring the sample back safely at the sea. moving boat. “They have said repeatedly that this is, technically speaking, the most complex mission they have ever flown,” Dr. Nollens said.

When the team set out to sea in September, they wanted to test a new, upgraded drone, with more Petri dishes and a longer flight time, that they hoped would collect larger volumes of breath. And then they encountered the stench.

Orcas live in groups, but providing personalized veterinary care requires the ability to identify individuals. It may be a complicated task, but the research team had one person on hand: Maya Sears, a citizen scientist from Seattle who has spent years learning the art of orca identification. “It might be a little pedantic, but I tend to think I more or less recognize whales, rather than identify them,” she said.

Mrs. Sears studied the cetaceans swimming in front of her. The killer whale had symmetrical saddle patches with a characteristic downward angle. She was J31, a 28-year-old woman known as Tsuchi.

The whales were still moving and swimming in groups, so as the drone took flight, Ms. Sears directed the pilot toward Tsuchi. “It would have been easy to mix them up,” she said. As Tsuchi exhaled, the pilot directed the drone into his nozzle; the Petri dishes returned to the boat glistening with whale breath.

The scientists also tried to measure Tsuchi’s temperature by placing the drone, equipped with an infrared camera, over his blowhole and measuring how hot he was inside his body. But the results were implausible, suggesting that Tsuchi, who was behaving normally, was four degrees colder than the whales swimming alongside her.

The most likely explanation, the scientists thought, was that something – a clot, a lump of mucus or swollen tissue – was preventing the camera from peering deeply inside its blowhole.

Back on shore, laboratory analysis of the breath samples was mostly reassuring. There was no sign of a bacterial or fungal infection, but a small amount of red blood cells suggested that Tsuchi was bleeding lightly somewhere in the respiratory tract.

The cause was impossible to pinpoint, but Dr. Gaydos suspected that Tsuchi may have had the equivalent of an orca nosebleed. “You know, she collided with someone else, she had some small bleeding,” he explained.

When the scientists encountered Tsuchi again, the smell had disappeared. Whatever the problem, it had been temporary.

“We’re not at the point yet where we could say, ‘Oh, and here’s my diagnosis, and here’s my prescription and my treatment,’” Dr. Nollens said. But was the fact that we were able to quickly assess a whale a cause for concern? “This is a milestone for me,” he said.

Scientists are developing additional techniques with a variety of partners, including Wild Orca, a nonprofit with a dog that can sniff out fresh whale feces. And they’re interested in creating a machine learning system that can detect anomalous movements and behavior in whale videos.

But they need to learn more about what is normal for these animals and discuss more about when to intervene. Scientists’ efforts to help Scarlet drew some criticism, especially when they considered temporarily capturing the whale for diagnosis and treatment.

Scientists know they can’t save the southern residents through veterinary interventions alone, but they hope to buy more time for the whales as broader conservation efforts continue.

“When we started, it was a pretty far-fetched idea to say, ‘We’re going to do veterinary tests on free-swimming wild orcas, and they won’t even know we’re doing it,’” Dr. – said Nollens. “It’s not far-fetched anymore.”