Seattle Times —
Researchers made a surprising discovery while tracking Chinook salmon in both the foraging areas of endangered southern resident orcas and the growing, healthy population of the northern resident orcas in B.C.
In a study published last week in the Canadian Journal of Fisheries and Aquatic Sciences, the researchers stated they expected to find the robust population of northern residents fat with fish, and the southern residents stuck with lean pickings.
Instead, the team found four to six times the density of big Chinook in the area they tested in the Strait of Juan de Fuca, part of the southern residents’ core foraging area, compared with the area they sampled in the northern residents’ territory, in the Johnstone Strait.
“It was the opposite of what we expected,” said Andrew Trites, an author on the paper and director of the marine mammal research unit at the University of British Columbia.