Blackfish

If the idea of SeaWorld makes you think of family fun married to an ocean conservation message then Gabriela Cowperthwaite's documentary will give you pause for thought. Her thorough film, which draws on detailed research and a surprising amount of archive footage, suggests that more sinister attitudes and worrying events lie beneath the theme park's glossy surface.

Blackfish is the tale of a whale, orca Tilikum, who has, unfortunately, lived up to his 'killer whale' tag, even though his species have never been known to attack a human out in the wild. Trapped off Iceland in 1983, Cowperthwaite charts Tilikum's grim existence, constructing a compelling argument that suggests the cruelty of captivity created a monster that would go on to take the lives of three trainers.

Initially kept at a low-rent Toronto theme park, Tilikum's life is portrayed as little more than a living hell for the first handful of years. Trapped in a tiny, dark tank for more than half of each day, he was bullied by the female whales also kept there and, unable to escape their wrath, was constantly injured by their raking of his skin. In addition, the training methods employed at that time involved punishing all the whales through removal of food if one of them made a mistake, which seems to have further fuelled the bullying. Enough, you suspect, to give even the strongest soul a few personality problems. A move to better living conditions at SeaWorld, saw his life only improve only marginally, with large chunks of solitary confinement still the order of the day.

As Cowperthwaite builds a picture of Tilikum's background, suggesting the baby steps that led to deadly aggression, she also draws on a wealth of first-person testimony from those who have worked at the parks down the years. These interviews form a second line of argument that claims poor health and safety standards were commonplace at SeaWorld, and alleges that the company put profit before trainer wellbeing.

A string of former park employees line up to reveal their lack of qualifications going in to the job - a role that seems to have largely been given out to anyone who was fit, keen and looked good in a swimming costume - and their concerns about whale welfare and Tilikum in particular. Meanwhile, the SeaWorld spin - from their talk of "trainer error" to the suspicious "facts" they peddle to visitors regarding the whales' lifespan and dorsal fin collapse - is, in many ways, even more shocking than the video showing the trainers in peril.

Cowperthwaite has amassed a worryingly large amount of footage showing acts of aggression by captive whales and there is particularly searing testimony from the Spanish wife of a trainer whose job cost him his life. Blackfish is inevitably likely to draw comparisons to The Cove, but unlike that polemic this is not a tunnel-visioned film. Cowperthwaite makes a good attempt to broaden out the debate, featuring testimony from a trainer who believes there is nothing wrong with keeping whales in captivity, although she is somewhat stymied by SeaWorld's refusal to take up her offer of right of reply. It's a refusal that feels like an own goal on the part of SeaWorld. If the park is so confident about animal welfare, why not put a counter argument? Tilikum, whose last victim Dawn Brancheau died in 2010, is still performing at SeaWorld - after watching this documentary, you'll think long and hard about taking your family to see him.