Ocean Park should strive to increase transparency regarding the conditions of captive dolphins at the park, said a leading marine conservationist.
“Bottlenose dolphins have a lifespan of about 40 to 50 years, and the park is often proud to say some of their dolphins can live up to this long," Samuel Hung Ka-yiu, chairman of the Hong Kong Dolphin Conservation Society, said in an interview with the South China Morning Post.
"But it’s not about the quantity of life, it’s about the quality of life that we are concerned about," he added.
Ocean Park moved earlier this week to dispel rumours that one of its dolphins had “attempted suicide” at the park's Marine Mammal Breeding and Research Centre, insisting that it was just normal behaviour.
The rumours spread when a video was posted on Facebook last week showing 14-year-old Indo-Pacific bottlenose Pinky throwing herself against a pool wall.
“As kids, we thought of Ocean Park as some sort of earthly paradise with blue skies and smiling dolphins … this earthly paradise is more like a marine purgatory,” the post, by citizen journalist website inmediahk.com, said.
But the park dismissed claims of attempted suicide or maltreatment of dolphins.
“Attributing human emotional labels to certain animal behaviour, such as calling them suicide attempts, might not be a correct expression to interpret or explain animals’ actions,” the park said in a statement posted on its official Facebook account  on Monday.
The park said the jumping action depicted in the video was a “unique but frequent habit of Pinky, which she has displayed since she was very young and it had not caused her injury in the past".
Hung said the park had been making slight improvements over the years, including curbing imports of dolphins, but overall, the park was still instrumental in generating consumer demand for dolphin shows.
"At the end of the day, no matter what they do to improve their lives, they can't give them enough freedom by confining them in a pool," Hung said.
He admitted that it was hard to tell from the video whether Pinky was attempting suicide, but pointed out that cases have been documented where captive dolphins deliberately hurt themselves when under stress.
Hung said: “The captivity industry is not very transparent and rarely do they open their books as to how the bulk of dolphin deaths occur. But in general, most behaviour demonstrated by dolphins in captivity is not considered natural behaviour...I'm sure cases of [dolphins self-harming] happen more than we think.”
Animal welfare groups have made repeated calls to the park for years to end “circus-like” dolphin performances as it gave a distorted impression of the animals’ life in the wild. The park has been urged to free the dolphins back into the wild.