B.C. study tracks breaths of killer whales using stunning drone video

The use of drones has helped researchers track the breathing patterns of killer whales off B.C.'s coast, and the videos offer a stunning glimpse of the majestic creatures diving and surfacing.

With the drones and underwater biologging tags, the researchers were able to confirm a long-held assumption – that orcas take just one breath between dives – while forming the clearest picture yet of their breathing rates during different activities.

Lead author Tess McRae, a masters student with UBC's Marine Mammal Research Unit, said their study should lead to a greater understanding of how much fish and other sustenance wild killer whales require in a day.

"We have northern resident killer whales, which are listed as threatened, and we have southern residents, which are listed as endangered – so it's really important for us to know how much energy they're using and how much food they need to survive," McRae told CTV News.

Since the massive marine mammals are not easily accessible or co-operative subjects, researchers use breathing patterns to extrapolate the amount of energy they're using during various behaviours.

The study determined orcas off the B.C. coast breathe 1.2 or 1.3 times per minute while resting and 1.5 to 1.8 times per minute while travelling or foraging for food.

By comparison, humans take about 15 breaths per minute while resting and 40 to 60 breaths while exercising – which highlights just how well orcas have adapted to their marine environment, researchers said.

"It’s the equivalent of holding your breath and running to the grocery store, shopping and coming back before breathing again," study co-author Dr. Beth Volpov said in a statement.

One of the drone videos captured a dozen orcas travelling together in a line, occasionally bobbing to the surface to inhale through their blowholes, exhale, and submerge once more.

While researchers have previously tried to track the animals’ breathing rates, McRae said those efforts used land-based observations. Her team tracked the orcas from the air and water for what they believe is a more accurate reading that can be used in ongoing conservation research.

"Once we understand how many fish these killer whales need in a day, then we can start looking at their prey populations," McRae said. "We can make different management decisions from there, so this is really kind of the first step in assessing that."