Southern pod killer whales aren't getting enough to eat, study finds

Roy L Hales/ Cortes Currents - A new study UBC study found that the endangered southern resident killer whale population isn’t getting enough to eat.

As lead author Fanny Couture explained, “The study goes from 1979 to 2020. We were trying to understand whether the Southern Resident Killer Whale population had enough food to eat to sustain their energy needs. So a human needs 2000 calories a day, a killer whale will need about 170,000 calories a day. What we found is that they were in energetic deficit for six of the last 40 years. Some of them are spread out throughout the study period, but three of the last year, so 2018 to 2020, they were in full energy deficits. So did not have enough food in the spring, the summer and the fall.”

This study is important to the Discovery Islands because we are close to the boundry between Northern and Southern Resident Killer Whales, which is just south of Cortes Island. Many Southern resident killer whales swim through our area, as does one of the major Chinook salmon runs they feed on.

Couture added that it would be good to apply the same study methods they would like to apply the same methodology to the Northern Resident Killer Whale population.

“There are evidences that they are also getting skinnier, that they are also potentially lacking food. It's possible that the different population trends that we observe for the Northern Residents and Southern Residents come from other seasons that we know less about, such as the winter,” said Couture.

“We need to understand the causes for the decline of those food resources. There are several hypothesis, several factors that might impact those food resources and the salmon population. One of which could be predation from other marine mammals, including Stellar Sea Lions, but there are other factors to look at as well, such as climate change, prevalence to diseases for those salmon populations. More research is needed and there is an urgency to try to understand what's happening to those Chinook populations.”