The Orca (Orcinus orca) also known as the Killer Whale is the most widespread species of Oceanic Dolphin, and growing to 30 feet in length, and 20,000 pounds in weight, is also the largest. Some populations of Resident (fish-eating) Orcas are critically endangered. However, in Alaska, many pods of Residents are doing much better than elsewhere.
In the second episode of Jeremy Wade's Dark Waters, Jeremy suspects Orcas may be a partial cause of the King Salmon's decline in Alaskan waters. Orcas are much larger and more intelligent than Salmon Sharks, so its possible that even after the sharks' feeding frenzy, surviving King Salmon have a very low survivability rate as a result of the Orcas.