Scientists said the death of the male dolphin, known as Qiqi, came as a surprise since the old dolphin appeared normal on Saturday.

Dr. Zhang Xianfeng, an expert with the Wuhan-based Hydrobiology Institute of the Chinese Academy of Sciences, said hebelieved the dolphin died of old age, but he and his colleagues would continue to investigate the death.

Qiqi was captured by a Yangtze River fisherman on January 11, 1980, and was shipped to the institute the following day. He was then 1.47 meters in length, 36.5 kg and approximately two years old.

Zhang said Qiqi spent 22 and a half lonely years in a 300 sq.m. pool by Donghu Lake near the Yangtze, the country's longest river,in Wuhan in central China's Hubei Province. The Yangtze is the species' main habitat.

Qiqi was a white-finned dolphin, a species unique to China, andthe most endangered dolphin species in the world.

When found, Qiqi was a badly bruised two-year-old. Experts examining him suspected the injuries were caused by illegal fishing, condemned as one of the main factors contributing to the decline of white dolphins in the wild. Numbers have fallen from some 400 in the early 1980s to far fewer than 100 now.

The Fishery Bureau of the Chinese Ministry of Agriculture has warned that the ancient mammal species which has survived 20 to 30million years of evolution may face extinction within another 25 years unless effective measures are immediately enforced.

China has tried every means to save the white dolphins. The Fishery Bureau has carried out a program monitoring Yangtze white-finned dolphins every November since 1997, the largest such monitoring program of rare animals in China. The search covers a 1,900-km stretch of the middle and lower reaches of the Yangtze River.

However, only five to seven dolphins have been sighted each season, even with the use of advanced location devices.

( July 15, 2002)