Country singer Martina McBride became the latest star to drop out of a concert at SeaWorld after the documentary film Blackfish that detailed the death of a trainer in 2010. McBride follows in the wake of Willie Nelson, Trisha Yearwood, Cheap Trick and REO Speedwagon, who announced their cancellation over the weekend. McBride didn't specify her reason for canceling, but In a Facebook post blamed "all the issues that have been aired recently" for her dropping out.

McBride was likely responding to a Change.org petition asking her to cancel that reached over 20,000 signatures before meeting its goal. Similar petitions have cropped up aimed at Justin Moore, Scotty McCreery and .38 Special -- but no word yet on whether they will perform.

UPDATE: The rock band .38 Special, which was slated to play alongside McBride and others, has announced that they are canceling their set as well in the wake of the film.