Thanks for posting that. It is interesting to see.
It is my understanding that both the Northern and Southern resident killer whale populations feed exclusively on fish, primarily salmon. The transient populations feed exclusively on mammals such as seals, sea lions, porpoise etc... So in this video, these would appear to be a group of transient whales.
I wish that our Southern resident population would branch out into mammals. We have a LOT of harbor seals. I wouldn't mind trading some seals to improve the viability of the Southern resident population. I think there are just under 90 individuals in that population and about 220 in the Northern resident population.