Shipping along the Yangtze River is the biggest threat to the Chinese sturgeon, an endangered species, fishery experts told a symposium on the protection of aquatic animals yesterday.

Ten sturgeons surpassing three meters in length have been found injured along the river so far this year. Nine of those fish died.

The number of injured fish found so far this year surpasses the total for all of 2005, the symposium heard.

"Shipping is the chief criminal," said Liu Jian, deputy director of the Administration Agency for the Shanghai Yangtze Estuary Protected Area.

Liu said shipping was responsible for about one-third of the approximately 20 Chinese sturgeons killed in the river since 2002, while illegal fishing was to blame for just over 20 percent of the deaths. The rest of the dead fish either became stranded, were ill or simply died of old age.

Ship propellers were to blame for three deaths this year alone.

A Chinese sturgeon found cut in half in the Yangtze estuary on May 2 was probably killed by the propeller of a large ship, experts said.

Officials from the Shanghai Fishery Office said they are considering a limit on ship speeds during the period the fish gathers in the river mouth.

Experts said they are also worried about the deteriorating environment along the river.

"With the exploitation of areas along the Yangtze River, wetlands in which big aquatic animals can lay eggs and breed have almost disappeared. The Yangtze River mouth has become the only resting place for them," said Shen Xinqiang, the chief scientist at the East China Sea Fisheries Research Institute.

The problem has forced many large aquatic animals into the estuary.

On February 15, a 2.62-meter-long pregnant pygmy sperm whale was found stranded at the river mouth. It died soon after it was spotted. On April 26, a 1.2-meter finless porpoise was killed by fishermen near Changxing Island.

"But now the estuary has also been seriously polluted," Shen said.

So far this year no wild young Chinese sturgeons have been seen in the protection area near the east coast of Chongming Island. The fish normally migrates to the area in the middle of May.

Officials said they will release the rescued Chinese sturgeon on June 17 together with 150 sturgeons to help improve the river's ecological balance.

(Source: www.shanghai.gov.cn )