Country star Martina McBride and band 38 Special are the latest musicians to drop out of SeaWorld's six-week concert series amid backlash against the theme park over allegations of animal abuse raised by one of this year's most influential documentaries, "Blackfish," CNN reports.

"Due to concerns raised by the CNN documentary 'Blackfish,' 38 Special will be canceling its scheduled March 9th concert at Seaworld," the southern rock band wrote on their Facebook page. "We appreciate the outpouring of support and especially apologize to our Orlando fans. We will try and schedule another performance in your area in the near future."

The 2013 documentary by filmmaker Gabriela Cowperthwaite details the events leading up to the 2010 death of senior SeaWorld trainer, Dawn Brancheau, who was killed by the park's traumatized captive orca, Tilikum, and explores the detrimental and sometimes deadly consequences captivity has on intelligent, highly social orca whales and their trainers.

Over the past several weeks, Trisha Yearwood, Willie Nelson, Cheap Trick, Heart and Barenaked Ladies have also cancelled their scheduled SeaWorld performances, spurred by pressure from petitions and fans on social media urging them not to support the theme park for the alleged abusive treatment of their animals.

CNN has been airing "Blackfish" regularly over the past few months, helping to draw more attention to the independent feature and its message. Barenaked Ladies was the first artist to cancel their performance after a Change.org petition urged them to boycott SeaWorld.

"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 on its Facebook page, while country music star Willie Nelson had a much firmer response: "I don't agree with the way they treat their animals," he said on Dec. 6. "It wasn't that hard a deal for me."