Hoi Wai, Ocean Park's 22-year-old killer whale and star attraction, has died after a sudden illness.
Around 50 staff, including vets, trainers and assistants, battled round the clock to save the whale after she fell ill on Friday. She died at 11.40 pm on Monday.
Park chief executive John Corcoran said staff were distraught. 'In the end she lost a great deal of blood and, to our extreme disappointment, died. It was a devastating moment when we finally lost her,' he said.
Marketing director Shirley Chung Bik-cheung said staff noticed the two-tonne whale, who typically ate 65 kilograms of fish a day, was suffering from diarrhoea on Friday.
'We discovered she was also passing blood. When we communicated the fact back to the United States they said it was very unusual,' she said.
It is hoped bacteria and virus tests will reveal the cause of the fatal haemorrhaging.