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The Chinese sturgeon, a prehistoric fish believed to be on the verge of extinction, lives in an appalling environment with the country's booming economy threatening to finish it off, an expert said in Beijing on Tuesday.

The rapid development of the economy, increased human activity and water pollution have all led to the fish's decline, according to Zhang Xianliang, director of the Yangtze River Fishery Research Institute with the Chinese Academy of Fishery Sciences, who was speaking at a forum on aquariums.

The Chinese sturgeon, considered a living fossil because it is one of the oldest vertebrates in the world, has existed for more than 200 million years, although it is not known how many remain in the wild.

The fish are mostly found in the Yangtze and its estuary just north of Shanghai.

The construction of the Gezhouba Dam on the river is believed to have decimated sturgeon numbers. The fish gather at the mouth of the Yangtze each spring to swim to spawning grounds upstream, but the dam project, which began in 1981, has cut the spawning area from 600 kilometers to just seven kilometers, Zhang said.

The number of Chinese sturgeon that migrate to the Yangtze River each year to spawn has dropped from 2,176 in the early stages of the project to just 500 today.

The fish is a protected species in China and people who catch or sell sturgeon face heavy fines.

Since the 1990s, China has been breeding the fish in captivity and releasing fry into the Yangtze in the hope of boosting flagging numbers.

"Despite the government's efforts, monitoring results show that the decline in the number of the fish has not been halted," Zhang said.

He said that the more money should be invested in protecting the endangered fish and more diverse methods of conservation should be used.

(Xinhua News Agency October 25, 2006)