First off, PETA's only concerns are money and notoriety. Animals don't have much to do with it, so there isn't any real need to consider anything from their point of view.
I am certainly happy to talk about zoos and aquariums, however, having been very involved in research from that perspective. It's a very complex issue that is rarely given the thought it deserves by public discourse, largely because it's really really complicated and the people involved in it are often afraid to put themselves out there and talk about their work (hard to blame them, really). But I'll attempt to break it down as best I can. For reference, I did a research internship at a top aquarium and have stayed in touch with many people from my time there.
First off, it's important to note that orca and beluga whale captitivy are very
separate issues. Orca capitivity is extremely controversial within the aquarium community, and many of the people I worked with wanted nothing to do with it, while acknowledging that the people at Sea World are genuinely doing the best they can. I don't feel qualified to talk about orcas, but I can
talk about belugas very extensively, as they were the whales I worked with personally.
Another important note: all zoos and aquariums are not the same. It's painful to acknowledge, but not every institution cares about their charges equally. However, it's easy to determine top-level institutions. AZA accreditiation involves an extensive review process and is difficult to achive. You can generally assume that an AZA-accredited facility is one that provides the highest level of care to its animals. The list can be found here: https://www.aza.org/current-accreditation-list
Alright, so, let me emphasize something: beluga trainers and researchers do not want
to capture wild animals. I'm not sure when the last beluga capture occurred in this country, but most animals in aquariums now have been there for decades and would not survive a release. Captive breeding programs are thoroughly preferred and have been relatively successful among belugas. Belugas are incomparably better-suited to aquarium environments than orcas, captive-bred belugas especially. Belugas are adaptable, non-aggressive whales who thrive with enrichment and form very deep social bonds with their trainers. They communicate incredibly well with humans and are not shy about informing people when they are unhappy (something I experienced when one of our whales became sick). Captive-bred whales are so thoroughly socialized from birth that they tend to seek out human contact whenever they can. We had one whale who would just hang out in front of the crowd and play with the kids all day, even when it was time for feeding! Not to say that our other whales weren't happy and social as well, but there was certainly a difference.
Was live capture morally justifiable back when it was widely practiced? That's a difficult question, but the benefits have been undeniable- both for whales and for humans. Aside from the establishment of a breeding program, the outreach effects have produced momentous change at a number of levels. Marine mammals are the most legally protected class of animal in the world, largely because it's impossible to encounter one and not
want to love and protect it. Research and conservation funding for marine mammals still isn't where it should be, but it's certainly higher than most other conservation fields (and I actually know quite a few researchers who resent the "charismatic megafauna" for siphoning a large portion of available research funding). And this is without even touching upon the many aspects of whale biology and conservation that we have
learned along the way. So is captive breeding justifiable? In my opinion, absolutely, as long as we're talking about beluga whales at an AZA-accredited institution.
In certain respects, there is much overlap between horse racing and the cetacean husbandry world. Both are widely villainized but are populated primarily by people who love the animals involved, particularly because there isn't much money involved at most levels. Both have had their fair share of bad publicity, some deserved because of nonrepresentative scandals in the field, some undeserved. Honestly, from the perspective of someone who loves and has been involved with both, I think aquariums are far more morally defensible because of their research and outreach capabilities. I know that can be a bit difficult to hear, especially on a racing forum, but isn't it true that the people who speak out most against aquariums first encountered and learned to love whales at those very institutions? Racing, as beautiful as it is, is still a sport at its fundamental level.
I didn't realize that there's a tv show about the Georgia Aquarium, but that's really encouraging to hear. Georgia, along with Mystic and the Shedd, is one of the most renowned beluga facilities in the world and does a lot of incredible work. We collaborated a bit during the beginning of that project, although our focus was on the stress levels and immune systems of the whales (developing ways to quickly and painlessly take biological samples from whales in order to judge their health both in captivity and in the wild). It's nice to hear that there is now a contast to Blackfish, which really outraged a lot of people in the community. I know people who were interviewed for that movie were furious when they saw how their words were presented in the final product, and it has unfortunately done quite a bit of harm to institutions that have nothing to do with it.
Happy to talk more about this and answer any questions people have about aquarium research and the like.