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Keiko

HEIMAEY, Iceland (CNN) -- Researchers are not sure whether Keiko, the killer whale star of "Free Willy," will ever be able to return to the open sea.

Scientists with the Ocean Futures Society are trying to encourage Keiko to return to the open ocean after 20 years in captivity.

The killer whale now lives in a bay in Iceland, and he's making some progress. But all those years in captivity -- and the interaction with humans -- may have stripped Keiko of the instincts he needs to survive in the wild.

Last year, during Keiko's first ocean forays, he shied away from wild whales. Scientists say bonding with a wild pod of whales would be Keiko's best chance of survival, because orcas hunt in packs.

VIDEO CNN's Natalie Pawelski looks at the probability of 'Free Willy' star Keiko moving from captivity to the open sea (August 14) Play video (QuickTime, Real or Windows Media)

Now, at least, Keiko interacts with the wild whales.

"Sometimes he chases whales, sometimes they chase him," says Charles Vinick of the Ocean Futures Society.

But playing tag with other whales is a far cry from swimming off with them forever.

Time is running out, at least for this year. Killer whales migrate, and they'll be moving away from Iceland in a few weeks. If Keiko hasn't bonded with any whale pods by then, he'll spend the winter in his pen in an Icelandic bay.

If the whale is never able to return to the open ocean, Ocean Futures officials say they will take care of him for the rest of his life.