The YouTube video posted by Travis Twizell, shows several sea lions trying to avoid the hunting orcas by sticking close to the sportfishing boat on Wednesday.
But in the end, the predators prevail and appear to wound and kill at least one of the sea lions.
YouTube: Killer whales attacking sea lions
Scientists have identified at least three separate groups of killer whales seen on the West Coast.
Resident orcas feed mainly on salmon and tend to live in larger family groups that travel over smaller ranges.
Biggs orcas, previously called transients, are slightly larger and live in smaller groups that travel greater distances as they prey on marine mammals.
Offshore orcas generally live 15 kilometres or more from shore in the largest groups of 30 to 70 animals, but occasionally come close to shore. They are the least studied of all the groups, but are smaller and thought to eat fish and sharks.