Save the Orca Killer Whales Sticker. The southern resident orca population has declined from 99 whales to 83 animals since 1994. Recent biopsy samples from J-pod whales have determined that this stock of genetically-distinct killer whale are heavily contaminated with polychlorinated-biphenyls (PCBs) and other toxins. While PCBs have been illegal in the US since 1978, this toxin stays in the benthic environment and accumulates within the muscle tissues of predators which feed on bottom-fish and other contaminated prey. Orcas, the pinnacle predator in the northwest marine environment, accumulate these toxins in their blubber and pass them to their unborn young across the placenta. This may explain the increased observed mortality among recent orca whale babies.