Southwest and SeaWorld part ways

Southwest and SeaWorld announced Thursday they are ending their longstanding partnership when the contract expires at the end of the year.

The promotional and marketing partnership began in 1988, cultivating opportunities involving airline passengers and the theme park's visitors.

But Southwest has been criticized by an animal rights group for its partnership with SeaWorld. A recent documentary, Blackfish, raised questions about the park's treatment of orcas, details of which SeaWorld disputed.

The advocacy group People for the Ethical Treatment of Animals had urged Southwest to drop the agreement, and Change.org gathered 32,459 signatures for a petition asking the airline to help stop animal cruelty.

The companies said their decision was mutual. Southwest said it's focusing more on local markets, while SeaWorld said it's looking to growing markets in Latin America and Asia.

Southwest's three planes with customized paint jobs featuring Shamu or penguins on the side will return to the company's traditional color scheme.

"Southwest and SeaWorld have enjoyed their long relationship, and wish each other continued success," the companies said in a statement.