By Dr. Holly Fearnbach, Marine Mammal Research Director

SR3’s Dr. Holly Fearnbach and Dr. John Durban have continued to collect valuable data on the health of Southern Resident killer whales (SRKWs) as part of their year-round monitoring of the endangered population. The team (joined by SR3’s Sadie Youngstrom in late June and early July) has been using an octocopter drone to non-invasively collect aerial images of SRKWs throughout the year to document seasonal changes in body condition (6/7 months so far this year), adding to data collected in 7/12 months in each of the past two years. These data are collected to help inform management actions aimed at recovering the struggling population.

Using measurements from aerial images collected between June 2023 and May 2024, Holly and John identified one individual SRKW to be in late-stage pregnancy, 14 individuals to be in poor body condition (BC1), and one individual that declined three body condition states from robust condition (BC5) to sub-normal condition (BC2) when they were last imaged. BC1 individuals have been found to have an elevated (2 x 3) likelihood of subsequent mortality. As such, these 15 whales were designated as vulnerable by an emergency rule issued by Washington’s Department of Fish and Wildlife, requiring commercial whale-watching vessels to stay at least one-half nautical mile away from the vulnerable Southern Resident killer whales this summer, and encouraging all boaters to Be Whale Wise and do the same. This management action is intended to limit disturbance from vessel noise to maximize the whales’ chances of finding and catching their primary prey, Chinook salmon. Starting in January 2025, almost all boaters will be required to stay 1,000 yards from any SRKW in Washington waters

This marks the highest number of whales that have been identified to be in poor condition during the 17 years of the SRKW health monitoring project. There are additional whales that also had shape profiles consistent with earlier stages of pregnancy when last imaged, but measurements indicated that they had not yet advanced to late stage (defined as the last six months of a 17-18 month pregnancy). The team will continue to monitor the success of these pregnancies and will hopefully document improvements in the body condition of the vulnerable whales.