In a perfect union of science and technology, marine biologists took to the skies this summer to investigate the effects of salmon fisheries on the federally Endangered southern resident killer whale population, one of the four resident communities in the eastern North Pacific Ocean. The concept of using Unmanned Aerial Vehicle (UAV) – aka drones – to study killer whale health was first conceived by Dr. Lance Barrett-Lennard from the Vancouver Aquarium Marine Mammal Research Program and Dr. John Durban from NOAA’s Southwest Fisheries Science Centre after the two attended several workshops on salmon fisheries and killer whales. Together with Dr. Holly Fearnbach from NOAA’s Southwest Fisheries Science Centre, NOAA biologist Wayne Perryman, and Don Leroi of Aerial Imaging Solutions, the researchers set about testing the concept that killer whale health could be ascertained from an individual whale’s width-to-length ratio, which might show slight changes in shape and condition.
Where previous aerial imagery could only be collected by helicopter at heights of as much as 800 feet (to avoid disturbing the whales), the use of drones allowed researchers to collect higher resolution imagery at closer distances of as little as 100 feet. This being a good Chinook year, the researchers found that while both the northern and southern resident killer whale populations were generally fit, malnourished whales could be distinguished from the air well before they showed signs of ‘peanut head’, a condition of severe malnourishment that manifests as an indentation that develops behind the blowhole from which afflicted whales rarely recover. Of note were sightings of pregnant females (which showed as visibly pear-shaped from the air); the natural loss of two northern resident whales, the older A37 as well as I63, a possibly sick female that had lost a newborn calf earlier in the year; and the opportunity to inspect a young female that had been caught underwater in a gill net before she was cut loose half an hour later for trauma or residual gear.
You can read more about the study and their findings on Barrett-Lennard’s blog, here.