ORLANDO, Fla. — SeaWorld Orlando has released the official cause of death for Kayla, the killer whale that died at the theme park in January.

• Kayla the killer whale died from lung disease, SeaWorld says
• 30-year-old orca had been at SeaWorld Orlando since 2006
• SeaWorld Orlando has 5 killer whales left in its care

Kayla died from lung disease, a SeaWorld spokesperson confirmed Monday.

"We determined Kayla died of lung disease, which presented very quickly in her case," SeaWorld's chief zoological officer Dr. Chris Dold said in a statement. "Lung disease is a common cause of illness and death seen in marine mammals in the wild, in human care and in those we rescue. It remains the leading cause of death for dolphins and whales throughout the world."

The results come from a post-mortem investigaton into what caused the 30-year-old orca to die unexpectedly. 

At the time, Kayla had seemed otherwise healthy before she began showing signs of discomfort over the course of one weekend. Despite treatment, her condition worsened. 

Kayla was born in captivity at SeaWorld San Antonio. She was transported to SeaWorld Orlando in 2006, where she remained until her death.

The theme park now has five orcas left in its care.

"As will all animals in our care, we will try to learn from Kayla's death," Dold said. 

In 2016, Seaworld announced the end of its orca breeding program after facing backlash following the release of the film, Blackfish. The 2013 documentary criticized the company's treatment of killer whales in captivity. 

SeaWorld, which suffered from declining revenue and attendence in the years after the film's release, has recently experienced a comeback.