I used to do a lot of kayaking. I see Orcas from time to time. Once paddling north of Port Hardy we came across an area where we found two harbour seal heads floating in the water, no bodies, fisherman later told us that a pod of orcas swam through the area and killed every harbour seal they could catch. I have yet to personally witness Orca's feeding, and maybe I don't want to.
It's crazy how smart they are. They are this close to having an actual language. They use tactics when they hunt. For example, when a shark is upside down it goes into a catatonic state called tonic immobility. Orcas will swim upside down to a shark, grab a hold of it then right themselves, flipping the shark over in the process. Boom, helpless shark. The movie Blackfish showed orcas coordinating to create waves to knock a seal off some floating ice it tried to retreat to.
I love sharks. But orcas are the apex predator of the sea.