By Dr. Holly Fearnbach, Marine Mammal Research Director
SR3’s Dr. Holly Fearnbach and Dr. John Durban have had a successful start to their monitoring of the “Sounder” gray whales during their annual stopover in Puget Sound to feed on ghost shrimp. A remotely-controlled octocopter drone has been flown non-invasively to collect aerial images of 9 whales, all individuals that have been imaged and measured each year since 2020 to assess their nutritional health. These images allow the team to monitor changes in body condition between years, as well as within the year, before they continue their migration northward to their Arctic summer feeding grounds. Comparative data on individual condition is important to help guide conservation measures to maintain adequate seasonal prey availability for the Sounders and assess how individuals are faring after the end of the Unusual Mortality Event that has been impacting the population since 2019.
Aerial images of two “Sounder” gray whales photographed in March 2024. Note the differences in body condition of the two whales: the whale on the left is lean and the whale on the right is robust. Differences in body condition are quantified by measuring widths along the profile of the whale. Images were collected non-invasively using an octocopter drone flown at >150ft over the whales under NMFS research permits 22306.