Our 2021 condition assessment of the “Sounders” gray whales off to a great start!
The “Sounders” gray whales have begun returning to Puget Sound and we have already been able to measure the body condition of four individuals. This is the second year of this collaborative research project between SR3’s Dr. Holly Fearnbach, Dr. John Durban of Oregon State University and colleagues from Cascadia Research Collective (CRC). We are using a remotely controlled octocopter drone to non-invasively collect high resolution aerial images that we analyze to measure in the body condition of individuals during their feeding stopover in North Puget Sound. Our aerial images can be linked to known individuals (some with 30+ year sighting histories!) thanks to the long-term monitoring efforts led by CRC. Both boat-based and aerial images were collected of all four whales, all of which were also imaged in 2020, allowing for evaluation of how body condition varies between years. One of these whales, CRC-723 or “Lucyfer”, was in much leaner condition compared to last year, likely an indication of a more recent arrival to the area. Hopefully we will see an improvement in condition for all of the whales as they fatten up on ghost shrimp before they resume their northbound migration to Arctic feeding grounds. This project will continue into early summer and results from this study will continue to provide important information on the body condition and health of gray whales during the current Unusual Mortality Event.
Aerial images of a “Sounder” gray whale (CRC-723, “Lucyfer”) taken on March 19th, 2020 and then again last week on February 24th, 2021. Note that Lucyfer appears more robust in the March 2020 image (left), likely the result of several extra weeks of foraging on ghost shrimp in Puget Sound. Images were collected non-invasively using a remotely-controlled drone flown at >150ft over the whales under NMFS research permit 19091. Photo by Holly Fearnbach (SR3) and John Durban (OSU).