SAN DIEGO — SeaWorld San Diego is mourning the loss of one of their beloved orcas named Nakai who died due to an infection, the animal theme park announced Friday.

Born at SeaWorld San Diego in 2001, the 20-year-old killer whale participated in hearing studies to help scientists better understand the impact on orcas of noise from ships and other human activity, spokesperson Tracy Spahr stated in a release. Nakai was known as a “curious and quick learner,” as he frequently picked up behaviors just by observing other whales in his pod.

“His contributions to helping improve the health and survival of whales in the wild cannot be underestimated and will never be forgotten,” Spahr said.

The zoological team says that aggressive therapeutic and diagnostic efforts were unsuccessful in treating Nakai’s infection.

A member of Nakai’s team who cared for him for 20 years called his bond with the orca “very strong.”

“He was very friendly and an overall playful guy who loved to interact with people. It was a joy to care for and learn from him and I will miss him greatly. He was a huge part of my life and of our family here at SeaWorld San Diego. We appreciate the support of the community as we grieve his loss together with his loyal fans everywhere,” the team member said.