The annual health assessment of the “Sounders” gray whale’s health assessment project is complete for 2021. This was 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).
Aerial image of a social group of “Sounders” gray whale taken in April 2021. Image was collected non-invasively using a remotely-controlled drone flown at >150ft over the whales under NMFS research permit #22306. Photo by Holly Fearnbach (SR3) and John Durban (Oregon State University).
The ongoing aim is to assess the health of these whales during the current Unusual Mortality Event for gray whales and to document their changes in body condition during this important feeding stopover in the Northern Puget Sound.
A remotely controlled octocopter drone was used to collect aerial photogrammetry images of 14 individual whales on seven days between late February and early June of this year. Eleven of these whales were measured on multiple days, with a maximum of four different days, and 11 of these whales were also measured in 2020, which will allow us to monitor changes in body condition both between and within years.
We saw a consistent and dramatic improvement in body condition during the spring feeding stopover and were able to document one pregnancy. The whales have now departed to resume their northbound migration to Arctic feeding grounds, and we will resume our health monitoring next spring when they return to Puget Sound.