A Southwest airlines jet. (Elaine Thompson/AP)

Southwest Airlines and SeaWorld announced Thursday that they will be ending a marketing partnership that has lasted for more than a quarter of a century, issuing a joint statement that basically promises us that they will still be friends.

While no official reason was given — the decision was made “based on shifting priorities,” the companies said — it came after Southwest was criticized for its relationship with the company that operates SeaWorld (as well as Busch Gardens and Sesame Place).

Many of these criticisms followed the movie “Blackfish,” a documentary that aired on CNN last year and pushed the issue of captive whales into the forefront. The movie explores this captivity and looks at the death of animal trainer Dawn Brancheau, who was killed by a whale at SeaWorld Orlando in 2010. SeaWorld has pushed back against “Blackfish,” defending its practices and questioning someone who looked into the whale attack.

A Change.org petition that cited “Blackfish” and called on Southwest to end the partnership had more than 32,000 signatures. In January, activists protested the partnership near the airline’s Dallas headquarters. That month, the airline posted a statement on its blog saying that it had heard the concerns.

“We are engaged with SeaWorld related to the recent concerns being raised,” the post said. “We are in a listening and education mode with the goal of upholding our commitments as a good corporate citizen.”

The marketing partnership, which began in 1988, will expire at the end of the year. The three Southwest planes that have been painted with whale designs will be repainted to return to the usual Southwest color scheme.