Scientists from NOAA Fisheries and the Vancouver Aquarium teamed up in August to trial monitoring the threatened northern resident killer whale population off the coast of British Columbia using a remote-controlled hexacopter. The team hoped that viewing the whales closely from the air would reveal insights into their health and well-being. The stunning aerial footage not only captured images that clearly showed whether individual whales were healthy, dangerously underweight or even pregnant, it also caught the whales swimming companionably alongside dolphins and affectionately head bumping each other and playing.
The northern resident killer whales feed on salmon, especially Chinook salmon. Recent declines in the runs of Chinook salmon have scientists worried about the flow on effects to the killer whale populations. Significant increases in deaths of southern resident killer whales have been observed in poor salmon seasons, so the team wanted to check the condition of their northern cousins to see what changes to fisheries management plans might be needed to accommodate them.
The team chose to used an unmanned aerial vehicle because it meant that they could get much closer to the whales without disturbing them. The hexacopter flew 100 feet above the whales and they showed no signs of being bothered by it. Getting that close meant that scarring and other tell-tale identifying marks were clearly visible. The team were particularly looking for differences in the width of the whales, which is not so easily observed from the water. When killer whales become malnourished and dangerously underweight they develop a condition known as “peanut head,” in which an indent forms behind the blowhole. Once a whale reaches this stage of weight loss it rarely survives.
The team tracked 77 resident whales and five transient Bigg’s killer whales during the two-week study. Fortunately, most of the whales were in good condition, as to be expected given that it was also a good salmon season. Sadly, however, two whales were believed to have died in the short observation period, both of which had been noticeably thin. Currently, scientists perform a summer census to assess the number of whales that may have died since the previous year. But as one of the researchers, Dr John Durban, remarked, “Mortality is a pretty coarse measure of how well the population is doing because the problem, if there is one, has already occurred. However, the hexacopter “can give us a more sensitive measure that we might be able to respond to before whales die.”
Photos by NOAA Fisheries and Vancouver Aquarium