The Chinese sturgeon, sometimes referred to as “the panda of the water” because of its endangered status, is thought to date back as far as 140 million years, to the Mesozoic Era. But the megadam era could be the death of it.

The recent travails of the venerable fish appear to illustrate a statement by Wang Xihua, deputy director of the Ministry of Agriculture’s Bureau of Fisheries, quoted in Beijing Review last year: “Years of research show that it is river damming, rather than overfishing or industrial pollution, that causes the worst damage to fishery resources.”

The first dam built on the Yangtze blocked China’s longest river in January 1981 and cut the Chinese sturgeon off from its traditional spawning grounds. It is still battling to survive, but its population has been decimated. Now a proposed dyke-construction project, which has gone virtually unreported in China, looks set to upset the delicate ecological balance in the species’ current breeding zone.

“When the Yangtze was dammed for the first time 24 years ago [for the Gezhouba hydroelectric project], the Chinese sturgeon was everywhere and easy to catch, especially in the section below the dam,” recalls Wei Qiwei, a senior researcher with the Yangtze River Fisheries Research Institute. “The fish was on sale in almost every market in Yichang.” Prof. Wei believes there may be only several hundred adult Chinese sturgeon now left in the river.

Liu Jian, an official with the Shanghai Municipal Agricultural Commission, says the species “might die out in five years unless appropriate measures are taken immediately.” Mr. Liu issued the warning during a press conference at which city officials announced a comprehensive five-month fishing ban, extending from May 1 to Sept. 30, in the waters to the east of Shanghai’s Chongming Island. Chinese sturgeon, listed since 1988 as a “first-class protected species,” cannot be caught legally anywhere on the Yangtze. (Scientists are allowed to capture alive a small number for research, but recently they have had trouble finding even the few their quota permits.)

The temporary ban on all fishing near Chongming Island has been introduced to prevent the migratory sturgeon from being caught accidentally as it swims through the area on its way to the sea.

Modern nemesis

The biggest of the Yangtze’s 400 fish species, and one of the world’s oldest vertebrates, the Chinese sturgeon is also the largest member of the sturgeon family. It can grow to four metres (13 feet) long and weigh 450 kilograms (1,000 pounds) or more.

Of all the modern pressures that confront this ancient leviathan (including a megadose of pollution, in the form of an estimated 24 billion tons of industrial waste and sewage dumped into the Yangtze every year), dams have emerged as its chief nemesis. And in a major international survey last year, the World Wide Fund for Nature said the Yangtze faces a greater environmental threat from dam building than any other river in the world, with 46 large dams already built, under construction or planned.

Chinese sturgeon reproduce in fresh water, but do most of their maturing in salt water. Adult sturgeon swim upstream from the sea to spawn in the middle reaches of the Yangtze, then lead their young back down the river to the estuary near Shanghai and out to the East China and Yellow seas, where the fry will feed and grow.