More than 20 baby Chinese sturgeon, also known as living fossils since they date back 140 million years to the time of dinosaurs, have just arrived at the Worldwide Fund for Nature Pavilion to meet last-minute Expo visitors. And the pavilion scientists looking after them said they have done enough to make sure the highly endangered species would not face the deadly fate that met the giant salamanders, another "living fossil" reptile, previously displayed at the Shaanxi Pavilion.

Blamed on an unfriendly environment, 15 giant salamanders died after being put on display at the pavilion representing the Shaanxi Province, arousing public concerns for the safety of other precious animals being exhibited at the Expo.

But inside the Life Ball, a 2.5m-tall, high-tech aquarium created for the fish, scientists have them under 24-hour watch, said Zheng Xifen from the Yangtze Fishery Resources Management Committee.

"We monitor elements of the water and quality inside the aquarium round the clock. There are technical controls to ensure the environment inside the ball copies that of the Yangtze River where all the displayed endangered fish originally come from," he explained.

Yesterday, the sturgeon arrivals were already getting accustomed to their new home inside the Life Ball, a centerpiece exhibit in the pavilion.

"They really look like sharks," said Teodoro Lim Ybanes, 62, a Filipino tourist closely observing the spheric aquarium. "This is the first time in my life that I have ever witnessed this living fossil fish. It's very impressive."

The 20-plus young Chinese sturgeons were brought to the Expo from a scientific research and breeding base on the upper stretch of the Yangtze River. The young fish are all among the second-generation of artificially bred Chinese sturgeon born at the Three Gorges breeding base on the Yangtze River last October, scientists said.

"Their birth means a major breakthrough and milestone for the protection of Chinese sturgeon," Zheng added. "It provides practical experience to revive the dying species by captive breeding in the future."

Increasing water pollution and human activity including the construction of the Three Gorges Dam have disturbed and caused deterioration to the biological cycle and living environment of Chinese sturgeon and other aquatic life, according to aquatic-life scientists.

Besides the star-attraction Chinese sturgeon, others aquatic species that have been displayed in the Life Ball include Baiji or the Yangtze River dolphin, paddlefish, cow fish, mullet and Songjiang weever.