The possibility of release is only possible if the whale has only been in captivity for a short time. An example of this is Springer, the killer whale that was treated for emaciation and nursed back to health before being rehabitated and ruined to their pod. For orcas like the whales at Seaworld (which has just been banned from further breeding! Yay!), these whales are unable to be released as they have been in captivity their whole life. All animals, including marine mammals, can be imprinted by human interaction. Captive whales are accustomed to being fed by humans and do not know how to fend for themselves in the wild. If they were released into the wild, these tame whales may attack boats and humans, thinking they will feed them and inevitably starve to death because they are unable to hunt. Whales live in pods otherwise known as their whole life. They hunt and feed with them. If a captive whale were to be released, it would be unable to hunt as they wouldn't have a pod that would assist them.