China’s beleaguered Yangtze

With the ecosystem under assault, Yangtze fish are more vulnerable than ever to their main nemesis: fishers. Up until 1980 or so, Yangtze fishers used small boats and nets, so the pressure on fish was not so heavy, says Xie. Then the industry became more mechanised - trawlers got bigger, nets more sophisticated - and fish stocks were hammered. To compensate, hatcheries have been replenishing stocks of carp and other key species. And since 2000, provinces along the Yangtze have instituted a three-month fishing ban covering the spawning season. Registered fishermen receive subsidies, including rice. The government is expected to extend the ban to four months starting next year.

But that strategy may be doomed to fail. In the summer of 2007, Xie’s team found that fishers in Dongting Lake - one of two large lakes on the Yangtze floodplain connected to the river - were hauling in an estimated 6.6 million juvenile carp a day. “Compared to this huge harvest, hatchery release of commercial species is small in number and meaningless,” Xie says. The juvenile fish, too small to serve to people, are ground up and used as aquaculture feed.

Targeted fishing bans would help some species. One fish that might be saved this way is Coilia ectenes, a kind of anchovy. The fish’s range on the lower Yangtze has been shrinking, and it spawns a month later than it did a few decades ago. Overfishing reduces the distance the fish swims upriver each spring for spawning. “Loss of migration distance is not restorable,” says Xie. That means genetic diversity will decline, making the anchovy more vulnerable to extinction.

The embattled fish might be saved by its own popularity. In late March and early April, a traditional time to eat the anchovy, prices for larger fish can top $500 per kilogram ($226 per pound). In a study last year, Xie found that large fish make up only 2 per cent of the catch but more than half the income for fishers. Most big fish are caught early in the season, so the solution is simple, says Xie: Ban anchovy fishing from April 15, when all that’s left, mostly, are the fry. The agriculture ministry’s Fisheries Bureau agreed to implement the ban this year. It will take a few years to determine whether this approach will preserve what’s left of the anchovy’s truncated migratory range.

Targeted bans offer only limited hope, however. What’s needed is a long timeout. Institute of Hydrology scientists are calling for a 10-year fishing moratorium. That’s doable, says Wang. China’s freshwater fish production is approximately 30 million tons a year, of which the Yangtze catch amounts to a mere 100,000 tons.

Although “fish quality in the Yangtze is the best in the country,” he says, officials should not be deterred from ordering a long-term ban to give fish stocks a chance to recover. All 20,000 or so registered fishers could receive compensation and be steered into other lines of work, the institute's scientists say. All told, around 100,000 people - the fishers and their families - depend on the Yangtze for their survival. Some fishers could be dispatched overseas as a kind of aquatic Peace Corps to advise less-developed countries on fisheries management, says former Institute of Hydrology ecologist Chen Peixun, China’s top baiji specialist.

Such a ban would have to be decreed by the Fisheries Bureau. So far, government officials are unmoved, but Wang says there is reason for optimism. “Since the situation of the Yangtze has been getting worse and worse, and the ban will have very little impact on the economy, it will be quite possible to impose a 10-year ban sometime in the next decade,” he says. A moratorium, adds Chen, “may be the only hope for the Yangtze.”

For those creatures that haven’t yet disappeared, that is.