Gabriela Cowperthwaite was a mum who took her kids to SeaWorld when the death of a killer whale trainer at one of the marine parks sparked her latest film-making project.

The documentary Blackfish was originally conceived without a point of view as Cowperthwaite set out to answer the question of why a top trainer at SeaWorld became the victim of the killer whale with which she worked and performed.

But the resulting film that opened in US movie theatres on Friday turned out to be a critical look at the consequences of keeping killer whales in captivity.

SeaWorld has launched its own campaign to challenge the criticism of Blackfish.

In a statement released last week, SeaWorld accused the film of painting “a distorted picture” of its facility, calling it “inaccurate and misleading”, as well as exploiting “a tragedy that remains a source of deep pain”.

Brancheau was killed in 2010 by the great orca, Tilikum, at SeaWorld in Orlando. Although reports differ as to how exactly she was pulled under the water, the autopsy report revealed she died of drowning and blunt force trauma.

Blackfish traces the life of Tilikum, who has been performing for 30 years since he was captured in 1983 around the age of two.

The Hollywood Reporter described Blackfish as “emotionally powerful”, “harrowing” and “a damning indictment of the SeaWorld theme park franchise”.

That was not what Cowperthwaite, 42, had in mind.

“I don’t come from animal activism – I am a mother who took her kids to SeaWorld,” she said. “I thought (the Brancheau) incident was a one-off.”

I thought (the Brancheau) incident was a one-off

Things took a turn when, during Cowperthwaite’s two-year project, she discovered that Brancheau’s death was not an isolated incident, and that Tilikum was involved in two other deaths since 1991.

By interviewing Tilikum’s former trainers, along with academics and whale experts, the documentary paints a portrait of a captive orca whose behaviour appears to come from the stress of the circumstances he was unwittingly placed in after his capture three decades ago.

Cowperthwaite said she exchanged e-mails with SeaWorld over the course of six months in an attempt to get its side of the story. She provided a list of questions she wanted to discuss, but in the end, the answer she got was “no”.

Former SeaWorld trainer Samantha Berg, 45, who worked with Tilikum when she was in her 20s, told Reuters it’s not about being “anti-SeaWorld” but “anti the way things have been done.

“I’m rooting for SeaWorld to change its business model, retire the whales and stop the breeding programme,” Berg said. “Given what we now know, there is a moral responsibility for us to do the right thing.”

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.