There are just 75 Southern Resident killer whales left in the wild. The plight of the struggling orcas is largely due to three factors: A dwindling Chinook salmon population, pollution, and boat noise interfering with the orcas' ability to hunt. KING 5 Environmental Reporter Alison Morrow explains how we got here and what needs to happen to help the orca population recover. MORE: https://king5.com/orcas