Time to let the orcas go

I've been to aquarium shows several times to watch the orcas, or killer whales, in their performances. I always enjoyed the shows and was fascinated by the animals themselves. For many years, I've felt the captivity of some whales was essentially more than worth it to the species and to whales as a whole. Captive orcas taught people that these are not mindless killers but intelligent, family-centered animals worthy of protection.
But it's time to let them go.
The horrific events at SeaWorld, detailed in the powerful book Death at SeaWorld, are reason enough. Of course, any large predatory animal is dangerous to keep captive: ask the lion keeper at the zoo.  But orcas have an especially hard time with captivity, and "angry" and self-destructive behavior is almost inevitable.  They are very large animals and often have lifestyles that can't be matched in captivity (transient populations that specialize in eating marine mammals are especially unsuited - we can't do a sea lion show and then throw the sea lion to Shamu, can we?) They have to circle in tanks that are, for them, very small, and often featureless inside, which for a creature that uses its sonar for much of its understanding of the world is like being in a roomful of mirrors.
There's no doubt the trainers and vets at these aquaria love the animals. They knock themselves out to provide the best care they can under the circumstances, and I'm the first to agree that, if we are determined to keep smart, gregarious animals in enclosures, the "tricks" are certainly more stimulating for the animals than just letting them swim around. And I've no doubt that some orcas, especially those born in captivity,  do find their interactions with trainers to be genuinely fun.
There may be some older orcas that can't be rehabilitated for a full ocean existence, like aging captive-born lions that wouldn't last two days in the wild.  In all cases, though, the animals can at least be moved to seaside pens where the trainers can be employed to teach them how to be wild orcas and sort out those animals that can't make the adaptation. Orcas in such situations can still be a source of income, as people can use walkways, live Web-feed cameras, and maybe even boats to observe them, though from distances that won't affect their retraining. At the same time, the orca tanks can be turned over to the smaller cetaceans, the dolphins and belugas, to give them more room and allow them to be kept in larger groups. (We may eventually decide we should let all cetaceans go, but for now, let's focus on the orcas as the least suited to captivity.)  I imagine that a lot of people would chip in for the rehabilitation process, "adopting" a whale and being kept up on its progress the way the world was captivated by "Willy" (Keiko) a few years back. 
I'm not, by any stretch, a marine mammal expert, just a naturalist with a longtime interest. There may be good counter-arguments, though I've not found any that are convincing to me.  We have indeed learned a lot about orcas from the close examination of captives, and millions of people have come to care about them. But the orcas have done all the good they can as ambassadors for the species, and we'll eventually have more tragic events that detract from that good. The orcas have made a great deal of money for the aquaria, certainly enough to recompense them for the money that might be lost from phasing them out. It's time to let killer whales punch the clock and go home. 

Blog on the continuing problems with captivity
Media information from SeaWorld

To learn more about orcas, two must-reads are:
Into Great Silence, Eva Salutis' memorable book following an orca pod in the wild
Orca: The Whale Called Killer, a  classic that taught the world so much about orcas