(CNN) Kayla, one of SeaWorld's oldest remaining orcas, has died after first showing "signs of discomfort" two days earlier, the chain of animal theme parks said.

The 30-year-old female orca died Monday morning, with animal care specialists by her side, SeaWorld said in a statement.

"The exact cause of death will not be known until the results of a post-mortem examination are complete, which may take several weeks," it said. "The entire SeaWorld family is deeply saddened by the loss."

Kayla had no major health concerns but first showed signs of an issue Saturday afternoon, and her condition worsened over the next two days, SeaWorld said. It described Kayla a couple years ago as a "graceful, intelligent, athletic" orca.

Kayla, a 30-year-old female orca, died Monday, SeaWorld says. Five orcas remain at SeaWorld Orlando.

An animal care specialist and veterinarians tried to help the orca recover, but she died at about 12:15 a.m. Monday at SeaWorld Orlando.

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