The Hong Kong Ocean Park said here Saturday that another Chinese sturgeon died Friday, raising the death toll of the rare aquatic species in the park to three in half a year.

The Hong Kong Ocean Park received five Chinese sturgeons from the Chinese mainland in June 2008 as a gift for the Olympic Equestrian events in Hong Kong. It was the first time the sturgeons has been sent outside the Chinese mainland. [File photo]

Tom Mehrmann, Chief Executive of the Ocean Park, told a press conference here Saturday that the Chinese sturgeon No. 1 had developed abnormal syndromes like the degradation of immunity and anorexia a few week ago.

Mehrmann said the health condition of the Chinese sturgeon No.1 suddenly deteriorated in the past two days and died Friday morning.

"We are sorry about another death of the Chinese sturgeon," Mehrmann said, "and we will have other seven alive Chinese sturgeons under our close monitoring."

He said five of the seven remaining Chinese sturgeons in the park were in good health but another two were in bad condition with similar anorexia syndromes. The theme park will shut down the sturgeon aquarium infinitely till further notice.

According to the anatomy results of the dead sturgeon No. 1, there were bruises in the fish head and extravasated blood inside, which might point to the park's salinating aquarium water for its death.

The Chinese sturgeons, which is thought to have lived at the same time as dinosaurs and found only in China, can live in both freshwater and saltwater, arrived in Hong Kong in freshwater in 2008 and have been undergoing a gradual transition to saltwater at Ocean Park.

Preliminary investigation showed improperly induced salination could have harmed the health of the fish and made them more susceptible to infection.

Wei Qiwei, a fellow researcher from the Yangtze River Fisheries Research Institute of the Chinese Academy of Fisheries Science, said at the joint press conference with the Ocean Park that more research was needed on keeping the species in different environments.

"The surviving rate for Chinese sturgeons in captivity is very low," Wei said, "thus it is hard for protecting the species."

"As the Ocean Park has never raised a Chinese sturgeon before," Wei said, "challenge and difficulty is expected for the park to nurse the fish properly. And the aquatic experts in the Chinese mainland will further cooperate with the park on further study and protection of the fish."

The latest death of the rare Chinese fish was the third of the rare Chinese sturgeon lost by the theme park in six months, after one was killed by a bite from a barracuda in June 2008 and another died of infection similar to the sturgeon No. 1 last month.

The Ocean Park received five Chinese sturgeons from the Chinese mainland in June 2008 as a gift for the Olympic Equestrian events in Hong Kong. It was the first time the sturgeons has been sent outside the Chinese mainland.

(Xinhua News Agecny January 4, 2009)