MIAMI — SeaWorld announced Thursday it will immediately stop breeding killer whales, essentially phasing out the iconic orcas from its theme parks following years of controversy over keeping them in captivity.

Park attendance at SeaWorld dropped after the 2013 release of the documentary “Blackfish,” which was highly critical of the orca program. SeaWorld reported a fourth-quarter loss of $11 million in February.

The company appeared to acknowledge that the criticism had helped drive the decision to end the breeding program. It also announced it would stop using the orcas in theatrical shows in the parks, instead introducing “new, inspiring natural orca encounters.”

“As society’s understanding of orcas continues to change, SeaWorld is changing with it. By making this the last generation of orcas in our care and reimagining how guests will encounter these beautiful animals, we are fulfilling our mission of providing visitors to our parks with experiences that matter,” said Joel Manby, president and chief executive officer of SeaWorld Entertainment, Inc.