I watched it... I'm not sure what to think. I watched it trying to keep an open mind. It's obviously a very emotionally charged documentary. There was basically only one guy to speak in any kind of opposition, and he had I think all of two clips where he didn't really get to make his case. I also tried to remember PETA could quite easily put together a boo-hoo, doggies in crates kind of documentary - and I believe the HSUS was involved with this documentary, at least were big supporters.
That said, there's obvious problems that come up in the documentary. Keeping orcas in captivity is bad for their health. Their lifespans are cut almost in half. Some kind of only 3% of males have tipped dorsal fins in the wild? Maybe that's insignificant, but it's an obvious physical affect of captivity.
The one guy they had arguing to the contrary made the point that he believes there's something wrong with Tilikum in particular that has made him the result of three deaths. And Tilikum was used as a breeding male so a huge percentage of the captive orca population now has Tilikum in them, so if there's legit something wrong with him he could have passed it on. There was one other death featured in the documentary that wasn't Tilikum. And several attacks by other orcas.
After I watched it I did some reading. Orcas haven't killed people in the wild but they HAVE attacked and injured them. So the attacks in captivity, is that a behavioural difference than what happens in the wild? By nature of humans interacting with them and training them, things will happen... dog trainers get bitten sometimes... it's just much worse when something happens by an orca than if you were training, say, a parakeet.
Also it seems like returning captive orcas to the wild doesn't go well for the orca. They tried to return Keiko (Free Willy) to the wild and were never unsuccessful. Keiko died in captivity. If he HAD lived longer perhaps they would have succeeded, but again with the shortened lifespans playing a part. Keiko was kept in an ocean pen which one of the ex-trainers recommended doing, but logistically I think there's legit concerns with that. An ocean pen still isn't big enough, how many of those pens can you have? And what happens when an ARist cuts the nets (which Sealand was afraid of) and the orca gets into the ocean and can't survive? Should you just humanely euth all the captive orcas instead..?
It does seem like orcas in captivity is not good for orcas in the long run. But then where do you draw the line? Ultimately no zoos? There are species who are highly highly endangered in the wild, species that are only around right now because of captive breeding programs... so do you just say boo to that, some species are meant to die out..?
I don't know the solution. It was a thought-provoking documentary, that's for sure. Not balanced at all, but that wasn't the point. It was to cause a very distinct reaction. I think they succeeded based on a lot of comment threads online I've read about it
ETA: I wanted to add, in response to the above - the criticism against Sea World for how they don't really prepare their trainers is, I believe, fair, given what was presented by the ex-trainers in the doc. They were selected for their skill as an entertainer, and how well they could swim... not because they were talented trainers.
Fran interned at a Sea World IIRC and I know she has some strong feelings on this. Hopefully she'll chime in.
ETA2: Also wanted to add... the last fatal incident involving Tilikum, the ex-trainers made several notes about the video of her accident where the trainer made some apparent errors and resulted in a frustrated animal. Then they were outraged that Sea World called the result an accident of trainer error. It seems to me like trainer error must have played a part, or the other trainers wouldn't have acknowledged the few things that happened. I don't think that means the attack was "her fault" (which I think is what they object to - Sea World is taking the track that this is the victim's fault) but it does seem like there were contributing factors that, if they hadn't happened, the end result wouldn't have been the same. It's a horrible accident and honestly, Tilly had killed one trainer and one other person. If he killed one trainer, that's probably just one trainer too many and he should have been retired from any kind of water work at that point. Fault rests with Sea World for encouraging it to continue, and it sounds like the trainer may have inadvertently caused Tilikum to be frustrated and he acted out as he apparently only knew how... by killing her.