You're right. They are not Fish, nor are they 'Whales'.
Eden 'was' famous for them long ago.
But alas, besides the Aboriginals there luring them in by deception of playing an old, lame man to arouse their sympathy to bring in food for them. A blow in also 'stabbed' one of them in front of the Pod, when it was beached when they tried to call for 'help'. They all left, except one old Orca (Tom) and then 'Strike 3' - a Dutch man took over the Whaling Station and refused to give Tom the tongue and Tom died from starvation and betrayal.
For an 'animal' (being?) to freely give their time and effort to us without domestication - we have let them down considerably.
They don't return to Eden and the Museum is just a relic of the past.
Maybe if Old Grapplar returns to Eden, they might come back?

Personally, i see the Orca (if they survive Humanity and its destruction of the world) as the best bet of 'Life' (GAEA) going out into the Stars, more than Humanity. They have more potential brain wise than we have and probably are just in 'lavae' stage of evolution. Who knows?
So far, we don't deserve to inherit the Stars and thus only 'machines' make it out there. Maybe an Android/Orca hybrid is the way to go. I doubt Humanity as we are, can make it.