(CBS News) The debate over the captivity and treatment of killer whales, also known as orcas, is rekindled in the new documentary "Blackfish."
David Kirby, author of the book "Death at SeaWorld: Shamu and the Dark Side of Killer Whales in Captivity," joined the "CBS This Morning: Saturday" co-hosts to talk about the documentary.
He said that people do not realize that whales often live with the same pod from birth and that when marine parks take them from their pods they are separated from their families.
Kirby said that there are signs of "what we would consider depression" in the animals' behavior. The killer whales then, in some instances, take out those emotions on other whales, which doesn't happen in the wild as much.
The documentary argues that trainers are also in danger of being hurt. The orcas are a mainstay at marine parks around the world such as SeaWorld, but aftermany argue that it is time to let the creatures go free.
SeaWorld declined to be part of the discussion but issued a statement saying "to promote ['Blackfish''s] bias that killer whales should not be maintained in a zoological setting, the film paints a distorted picture that withholds from viewers key facts about SeaWorld ... Perhaps most important, the film fails to mention SeaWorld's commitment to the safety of its team members and guests and to the care and welfare of its animals."
Some animal activists say that killer whales should be released, but Kirby doesn't think that it's a possibility for captive-born orcas to be sent back to the wild. He suggests a different solution that would still allow the marine park to bring in money.
"All animals in entertainment get to retire after they work," said Kirby. "These animals work literally to the day they die, and we think a netted-off sea pen where they could sort of unlearn everything SeaWorld has taught them, they could live out their lives. SeaWorld could charge people to come watch them in a more natural setting. It's a win, win, win for the public, for the whales and for SeaWorld."
For David Kirby's full interview, watch the video in the player above.