In the meantime, it would help to list specific killer whale populations as threatened or endangered, says Jepson. Technically, all killer whales belong to the same species, Orcinus orca. Scientists debate whether they should recategorize the whales into subspecies, says Jepson, and doing so would make it much easier to protect groups in more polluted areas. Legal protection can motivate countries to clean up their PCBs and take a more active role in protecting the whales. But scientists are a long way from resolving the subspecies debate, Jepson says.