Whale Snot, Delivered by Drone

Researchers are using aerial vehicles to study infectious disease in Arctic cetaceans.

Above the icy cliffs of Norway’s northern coast, the horizon melts from tangerine to pink before cooling to a velvet blue. It’s midday in November, and this is the brightest it will be all day; polar night conditions mean the sun stays below the horizon for months. In the dark waters below the ocean’s choppy surface, humpback whales and orcas feast on herring, whose abundance is unique to the fjords of this region.

From a seven-meter vessel, four researchers all reach for a small uncrewed aerial vehicle — or drone — humming in the sky above the boat’s bow. The device is visible with the help of bright-colored foam floaters taped to its undercarriage, but as the boat fights high winter winds and rough waters, the drone is hard to catch. Once successfully caught by a team member and retrieved from flight, the group hurries to preserve and protect the drone’s precious cargo.

“It’s really this gooey, snotty thing,” says Helena Costa, a veterinarian and PhD fellow at Nord University.

whale in artctic

In the Arctic, infectious diseases pose threats to whales and other wild marine life, making their study essential to conservation. Photo by Helena Costa.

She’s referring to the samples she and her team swab from Petri dishes containing exhaled breath condensate of nearby humpback whales. They’ve recently published findings demonstrating how store-bought drones effectively collect samples of whale breath, or snot, in Norway’s harsh arctic winters.

The researchers hope these samples can be used to monitor and protect wild populations of whales. Infectious diseases like influenza and morbillivirus are considered a serious threat to wildlife. Collecting baseline data on pathogens and respiratory illness is imperative to monitor the health of wild populations, especially those who migrate north and rely on Arctic ecosystems. As water temperatures rise worldwide, helping Arctic species survive and be resilient is critical, says Cesc Gordó-Vilaseca, also a PhD student at Nord University. “There is nothing more northern than the Arctic,” he says, “these species don’t have anywhere else to go.”

But studying infectious diseases in cetaceans, like humpback whales and other migratory marine mammals, is challenging. Most available data comes from captive animals which aren’t always representative of wild populations. Stranded whales are another primary source of data, but in Norway, which has a small human population and massive coastlines, stranding networks aren’t always active or available for collecting samples from a stranding.

Even when there are large feeding events like in the fjords near Skjervøy, Norway, “a whale isn’t like a dog that you can just pick up and take a blood sample,” says Costa, who came to Norway from Portugal to study infectious disease. Blood and fecal samples, which are used for studying infectious illnesses in other mammals, can’t be obtained consistently from cetacean populations. Not to mention that gathering these samples is invasive.

That’s why researchers often turn to blow samples. In the past, scientists have collected these samples from free-swimming whales using more disruptive methods, like holding a long pole and plastic panels above a whale’s spout from a nearby boat. Drones allow for less invasive data collection by granting greater distance between the research vessel and the whale, but samples collected in this manner haven’t yet been used to study infectious diseases. And, drones are usually expensive — often upwards of $40,000 for a single custom-made machine.

Costa and her team wanted to use a process that was easier on the animals, and lighter on the budget. Partnering with members of Ocean Alliance, the whale conservation and research organization based in Gloucester, Massachusetts, that pioneered the flagship SnotBot program using drones to collect whale snot in 2015, they designed a methodology for collecting samples using only consumer items. “Traditionally, collecting this high-quality data has been really expensive,” says Ocean Alliance’s Science Manager Andy Rogan, “and this methodology is game changing for the industry.”

Most required materials you’d find in your local craft store: foam floaters, velcro, glue, and Petri dishes. The drone, a DJI Mavic 2Pro drone, is the most expensive part, but is still a fraction of the cost of custom drones made specifically for marine research. Some research programs have access to tens of thousands of dollars and robotics departments that can help design and produce customized equipment. But for teams without that kind of access, “it’s great to have something that works that’s already available,” says Costa.

boat in arctic

Harsh conditions and short winter days create unique challenges for the study of Arctic whales and other marine mammals. Photo by Helena Costa.

researcher in arctic

Researchers are now using low-cost, consumer drones like this one to collect the exhalations of whales as they surface. ​Photo by Helena Costa.

For six days in November 2021, Costa’s team left the small town of Skjervøy for Kvænangen, a nearby fjord, in search of humpbacks to test their new design. They departed the coast each morning and boated twenty minutes offshore. Without the rising sun, the light stayed low as they scanned the fjord’s choppy waters. Once they spotted whales, they moved close enough to monitor the animals’ behavior, surface intervals, and respiratory rates while maintaining a safe distance. They waited for the whales to take their next deep dive, then quickly prepared the drone for take-off before the whales resurfaced. “In these sort of drone operations,” says Rogan, who’s worked on projects like this for over a decade, “we’re really running on instinct.”

When whales resurfaced, the captain moved the boat within range for drone connection and the researchers — sporting face masks and gloves to avoid contamination — removed the Petri dish lids. They launched the drone, using its live video feed to follow the whale’s movement while maintaining a 20-meter distance above the water’s surface. After the whale’s exhale, the pilot directed the airborne drone down to capture a spray sample on the dishes, then directed its retreat to the boat. Especially tricky was making sure the device returned safely before its fragile battery died in frigid temperatures. Once they pulled the drone from the air above the boat, team members sealed snot samples with sterile lids and placed them in liquid nitrogen to be tested back at the lab.

If multiple whales were present, the researchers collected a group sample. The team also recorded metadata — including environmental conditions, whale group size, and life stage, among others — and took water and air control samples. Out of 34 flights, 16 successfully collected samples from 11 groups of humpback whales in the area.

The pilot study represents the first effective sampling of baleen whales’ exhaled breath at northern latitudes during winter and polar nights.

That’s no small feat. Winter conditions are harsh; these flights were conducted in winds up to 31 km/hr and temperatures as low as minus 19 degrees Celsius. But Costa says winter in Norway offers a unique opportunity to sample humpbacks. “It’s a very unique aggregation of animals that you don’t find in other places,” she says. After migrating from warmer waters where they’ve given birth, humpbacks are the most relaxed in Norway’s fjords, where herring are abundant.​​“It’s the most beautiful thing,” adds Gordó-Vilaseca, who was onboard for these collections, “nothing beats Northern Norway in winter.”

Since the pilot study, Costa has continued working with consumer drones in other regions of the Atlantic Ocean, including waters off Iceland and Cape Verde. And the method is catching on — researchers involved in this work since the pilot study have brought it to their own projects in Ireland and the Pitcairn Islands.

Now, Costa hopes to start screening the samples she collected for specific pathogens. An avian influenza outbreak in 2022 has been connected to mass mortality events in seals and other marine mammals in the Atlantic; Costa wonders if humpbacks are exposed to and impacted by the virus. She also hopes to use the methodology to study the whales’ respiratory microbiome throughout their migration.

While humpback whales are one of the most studied cetacean species, better understanding their exposure to infectious disease is imperative for protecting wild populations, especially in a changing climate. This methodology could help foster that understanding. “If we can’t protect Arctic species,” says Gordó-Vilaseca, “we lose global species richness and biodiversity, forever.”

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