(CNN) -- Add Heart to the list of bands that are bowing out of a show at SeaWorld because of the CNN documentary "Blackfish."
"Heart has chosen to decline their forthcoming performance at SeaWorld on 2/9/14 due to the controversial documentary film 'Black Fish,'" the band said Sunday on its verified Twitter account.
Sisters Nancy and Ann Wilson did not elaborate.
A SeaWorld spokesman did not immediately respond to CNN's request for confirmation and comment.
But the duo isn't the first to cancel a concert at the Florida theme park because of the film.
Country singer Willie Nelson and Canadian rock act Barenaked Ladies also pulled the plug on their shows.
The documentary -- which first aired on CNN in October -- tells the story of the killing in 2010 of experienced SeaWorld trainer Dawn Brancheau by a 12,000-pound orca.
The film raises questions about the safety and humaneness of keeping killer whales in captivity over the past 39 years.
Moved by the documentary, fans started online petitions asking musicians to stay away.
When the Barenaked Ladies nixed their plans to play at SeaWorld last week, they explained that it was a decision made after viewing "Blackfish."
"This is a complicated issue, and we don't claim to understand all of it, but we don't feel comfortable proceeding with the gig at this time," the band said in a Facebook post.
Nelson and his representatives did not immediately respond to a CNN request for comment.
SeaWorld spokesman Nick Gollattscheck confirmed Nelson's decision not to sing at SeaWorld, but he cited reasons other than the documentary and petition.
"Due to scheduling conflicts, Willie Nelson will not be appearing at SeaWorld Orlando's Bands, Brew & BBQ event in 2014," Gollattscheck said in a statement.
For its part, SeaWorld says the documentary ignores the park's conservation efforts and research.
"'Blackfish' focuses on a handful of incidents over our long history at the exclusion of everything else," wrote Michael Scarpuzzi, vice president for zoological operations at San Diego SeaWorld, in an op-ed on CNN.com. "Not a single interview with a guest who was inspired and enriched by their experience with killer whales at SeaWorld. Not one visitor who left SeaWorld more aware of the need to preserve the world around them. Not one word about the thousands of ill, orphaned and injured animals rescued by SeaWorld or the millions of dollars we dedicate to supporting conservation and research."