World's oldest orca in captivity may be set free after 52 years

She has been kept at Miami Seaquarium for five decades but a pact will see Tokitae brought to Puget Sound

Tokitae the orca is expected to return to her home in the waters of the Pacific after more than 50 years. AP

A killer whale kept in captivity since she was caught as a baby may be on the path to a new life of freedom, after an agreement was signed between the theme park that keeps her and an animal rights group.

The orca, known as Lolita or Tokitae, was about four years old when she was captured in Washington state's Puget Sound in the summer of 1970, during a time of deadly round-ups of the creatures.

She spent decades performing for paying crowds before falling ill.

Now a philanthropist, Indianapolis Colts owner Jim Irsay, has teamed up with a rights group to give her a chance to swim in the open ocean within 18 to 24 months.

“I'm excited to be a part of Lolita's journey to freedom,” Mr Irsay said. “I know Lolita wants to get to free waters.”

The agreement between Mr Irsay and Eduardo Albor, who heads The Dolphin Company that owns the Seaquarium, and the Florida non-profit Friends of Toki, co-founded by environmentalist Pritam Singh, still faces hurdles to gain government approval.

The cost could reach $20 million. There are concerns Tokitae could bring diseases from captivity with her to the wild.

The whale thought to be her mother, Ocean Sun, is more than 90 years old and still swims wild in the area of Puget Sound. But before any hope of a reunion can take place, Tokitae will need to be taught to fish and build up muscle in an ocean sanctuary, as orcas typically swim about 160km per day, said Raynell Morris, an elder of the Lummi Indian Tribe in Washington who also serves on the board of Friends of Toki.

“She was four when she was taken, so she was learning to hunt. She knows her family song,” Ms Morris said. “She'll remember, but it will take time.”

Tokitae — now 57 years old and weighing 2,267 kilograms — currently lives in a tank that measures 24 metres in length and is 11 metres wide and six metres deep.

The push to free Tokitae gained momentum after the 2013 documentary Blackfish highlighted the captivity of orcas.

Animal rights advocates for years fought unsuccessfully in court to obtain her freedom after the National Oceanic and Atmospheric Administration added orcas to the endangered species list in 2015.

Killer whales are highly social mammals that have no natural predators and can live more than 80 years.