Over the years, Vancouver, Canada, has gained a reputation as one of the world’s best places to see orcas in the wild. But despite their apparent prevalence, both the Vancouver coast’s northern and southern populations are at risk, with the former classified as officially threatened and the latter as endangered. American and Canadian research teams have agreed that the health of resident orca pods depends heavily upon the successful spawning of Chinook salmon each year, an assumption that’s supported by orca mortality rates, which fluctuate in direct correlation to the abundance of salmon in the area. Scientists have thusly concluded that starvation and malnutrition are leading factors in the decline of Canadian orca populations.
However, while existing research demonstrates this pattern between increased orca deaths and poor salmon seasons, until now there has been little success in terms of monitoring the body weight of individual whales. Although an orca’s length can be accurately measured in profile, such measurements reveal very little about a whale’s overall condition. Determining an orca’s weight is made even more difficult by the fact that as they lose fat from their blubber, it’s replaced with water in order to maintain the whale’s streamlined shape. Malnutrition only becomes visibly apparent from a side-on perspective in its advanced stages, when it can be recognized by an indentation behind the blowhole. Once a whale reaches this stage of starvation, it’s very rarely able to recover.
In 2013, Dr. Lance Barrett-Lennard of the Vancouver Aquarium Marine Mammal Research Program and Dr. John Durban from NOAA’s Southwest Fisheries Science Center recognized the importance of diagnosing food stress in orcas before they reached this critical stage, which meant being able to recognize thinness, as well as starvation. It was hoped that more conclusive research would help to inform the management of salmon fisheries such as to ensure orca survival. In order to do this, Durban and Dr. Holly Fearnbach (also from the Southwest Fisheries Science Center) hypothesized that they would need to observe the whales from above, so as to use length-to-width ratios to distinguish healthy whales from those that were underweight.
The team first used manned helicopters to acquire aerial images and footage of wild orca pods. Although the results of this research proved that orca body condition could be more accurately assessed from the air, the team found two major drawbacks to this method: the helicopters were expensive to run, and they had to operate from at least 820 feet (250 meters) above sea level to avoid disturbing the whales, therefore producing low-quality images. The solution to these problems came from another NOAA scientist, Wayne Perryman, who had been working with Don LeRoi of Aerial Imaging Solutions to study penguins and sea lions using an Unmanned Aerial Vehicle (UAV).
In August 2014, a research team consisting of Barrett-Lennard, Durban, Fearnbach, Perryman and LeRoi set out to conduct the first-ever study of orcas using an UAV, which in this case was a remote-control APH-22 marine hexacopter that could fly just 98 feet (30 meters) above sea level, and which was affectionately dubbed “Mobly” by the research team. Producing just 38 decibels of noise, Mobly produced high-quality, detailed images of wild orca pods that were seemingly oblivious to its presence. Over the course of two weeks, the research team took over 30,000 images of pods living in Johnstone Strait, as well as a considerable amount of video footage. Mobly observed 82 individuals, including 77 members of the northern resident pod, and five transient Bigg’s orcas.
Thanks to the clarity of the hexacopter’s images and footage, the team easily identified individuals based on unique scratches and scars on their saddle patches. They could also distinguish between skinny and healthy whales, and those females that were pregnant. Being able to identify pregnant whales and subsequently the fate of their calves could help further research on neonatal mortality rates amongst orcas, proving that the UAV footage has multiple uses. In terms of confirming the correlation between orca mortalities and the abundance of salmon in the region, Mobly seemed to support the existing hypothesis: most of the whales were of a healthy weight, which aligned with the fact that 2014 has been a good year for Chinook salmon spawning. Sadly, two whales that appeared malnourished had disappeared by the end of the two weeks, and are presumed to have died of starvation.
This first foray into using UAVs for orca research has shown the value of remote aerial observation when it comes to marine biology. As well as being able to determine the orcas’ condition, the research team gained rare insight into the private lives of the orca pods. They witnessed social behaviors, including complex family relationships, and unique fishing and hunting techniques.
“The bottom line is that the method worked wonderfully well,” said Barrett-Lennard. “We are convinced now that Mobly — or one of his cousins — will be an invaluable part of our research program for years to come, as we focus on recovering resident killer whale populations by, among other things, ensuring they have enough to eat.”
The future role of UAVs as a scientific research tool is under threat, however, thanks to the Federal Aviation Administration’s decision to prohibit the machines for commercial use (including research) without a license. Commercial use of UAVs is illegal in in several countries, and obtaining a permit is often a difficult and lengthy process. But for now, it seems that this legislation is the only limit to the potential research value of machines like Mobly.
