If you’ve ever visited SeaWorld, you will probably remember the image of giant, majestic orcas splashing and cavorting with a playful grace. But do you also recall the news story from 2010, when SeaWorld trainer Dawn Brancheau was killed by 12,000-pound killer whale Tilikum? Blackfish, a new documentary by director Gabriela Cowperthwaite, dissects the lives…

