A lot of documentary filmmakers make movies about the causes that consume their lives. For "Blackfish" director Gabriela Cowperthwaite, however, the discovery of SeaWorld's lack of safety measures for both its trainers and the whales themselves caught her off-guard the same way it did many people: In 2010, head trainer Dawn Brancheau was killed by Tillikum, a SeaWorld orca captured in the wild in the early eighties and responsible for several violent incidents since then. The movie digs behind the scenes for the whole story. "Blackfish" culls from shocking footage of killer whales at SeaWorld showing their frustration over poor captivity conditions while including candid testimony from ex-trainers. Both an activist cause and a wakeup call for anyone who has attended SeaWorld in the past, the movie instantly got people to start talking when it premiered at the Sundance Film Festival and landed distribution with Magnolia Pictures. Cowperthwaite talked to Indiewire about the genesis of the project.

A lot of people remember when a trainer was killed by an orca at SeaWorld a few years back. But most don't realize that a lot of the reports -- like that the trainer died because she was wearing a ponytail that the orca tugged on -- were actually conjecture.

There are a lot of people who wonder how the ponytail plays into it. It really is the power of marketing or spin that lets you hold onto that strange little fact about the ponytail that has since been disproven. But it's the first thing you heard, so you stick with it, and that's the story you regurgitate. In fact, that's the first thing that people say when I tell them about the film that I made. They say, "Oh, yeah, the orca grabbed her by the ponytail."

Were you surprised by a lot of the details behind SeaWorld's history with safety issues for both the whales and trainers when you started working on this project?

I had been paying attention to general media about it, but I was also surprised. When I started peeling back the onion, I figured there had to be more to this story: Was [the whale] playing with her? Was he angry? Why would a whale do this?

What was your access point for the story?

I was a mom that took her kids to SeaWorld. That's my entry point, unfortunately. I really didn't know anything about it. And another thing that always make me feel strange is that my entry point was that Dawn was killed by an orca. My entry point was a human death. There's something scary, bizarre and sensational about it that worked on me. So I guess in my mind if that triggered something in me, that if a film had a chance to allow me to pull back the curtain, maybe I could pull back the curtain for the general public.

"I was a mom that took her kids to SeaWord. I really didn't know anything about it."

SeaWorld declined to do any interviews for the film. Did you expect that they would cooperate more?

Yeah, I did. I'm naive that way. I also don't come from any past activism or even really controversial filmmaking. My past films are sort of slightly more touchy feely and inspiring, so I expected they would look at this as an opportunity to tell me what they do, why so many people are enchanted by these shows, and why they're a $2 billion industry. Tell me what I'm falling in love with when I take my kids there. I wanted an answer from them. I think the more I found out and the more I discovered, the more I realized that at a certain point there was no way they could come off as not being defensive. Why was a trainer killed in their park? They're automatically on the defense and never going to look good. They told me they would think about it -- that it was very likely I would be granted an interview, and then six months later told me no. I don't know if they were serious or if they were just entertaining the idea.

Did you try to show SeaWorld the movie before it premiered at Sundance?

No. You can't open yourself up that way. At some point, this is one of those journalism issues. I do see myself as an even-handed person. So when I asked them for an interview, I was really genuine about wanting that interview. I wanted to be that diplomatic person. Yet at some point you could risk being faithless to the truth. All of a sudden in trying to give them five minutes and these people five minutes, I wouldn't be telling a truthful story. My directive was to let the narrative guide me and just stay disciplined. If people take hits during that storyline, so be it -- it's the truth.

What about the ex-trainers who speak candidly in the film? Were they nervous about getting involved?

They definitely were. A lot of them were pretty brave and came out after Dawn was killed and were sort of outspoken. So those folks felt a little more comfortable. But there were people who were not comfortable, who hadn't quit years and years ago but rather more recently. They were very hesitant and scared about coming forward. On two separate occasions, two people canceled interviews after we'd flown there.

Are they still in the movie?

One of them. One of them came around a month later.