It appears there are more fish in the Salish Sea for southern resident killer whales than originally believed.
According to a University of British Columbia-led study, conducted by the Marine Mammal Research Unit and published in the Canadian Journal of Fisheries and Aquatic Sciences, the number of Chinook salmon in the Salish Sea during the summertime is four to six times more abundant for southern resident killer whales than what is available for northern resident killer whales in the Johnstone Strait.
Dr. Mei Sato, a research fellow at Marine Mammal Research Unit (MMRU) at the Institute for the Oceans and Fisheries at UBC and lead author of the paper, said she and her colleagues had long believed that the southern resident whales, whose population is endangered, wasn’t thriving due to their main source of food — Chinook salmon.
“I was surprised to see this result,” Sato told CHEK News.
Sato and her team examined Chinook populations and their availability for southern residents between 2018 and 2019 while also examining the Chinook availability for northern resident orcas in the Johnstone Strait at the same time.
Through their research, Sato and the team discovered that there are far more salmon available to the southern residents in the Salish Sea than the northern resident orcas, which have a population that hovers around 300.
Dr. Andrew Trites, professor and director of the Marine Mammal Research Unit, said they expected to find the opposite in terms of Chinook salmon population.
“We were really surprised to find the opposite, that was four to six times more fish available to the southern resident killer whales here during the summertime. When we were doing our surveys,” he said. “Nobody predicted that.”