'Customized' crustaceans

Hairy crabs, or Chinese mitten crabs, are widely distributed along the estuarine deltas, inland lakes and waterways as far north as the Korean Peninsula and as far south as the river mouths in Fujian province of southeastern China.

In the north, the crabs are simply known as he xie or "river crabs". Further south, they are known as dazha xie, which literally translates to "big sluice crabs", a name that reflects the traditional way of catching the crustaceans by trapping them with bamboo sluices.

As in all things natural, the crabs flourish best where conditions suit them, and Yangcheng Lake has some of the most conducive environmental factors for mitten crabs to grow fat and delicious.

The lake's water is unpolluted, it is relatively shallow with a hard, sandy bottom and there are lots of aquatic plants - the makings of a crab paradise if conditions are left undisturbed.

To the connoisseur, the happy, healthy, bright-eyed Yangcheng Lake hairy crab has some distinctive characteristics: a shiny blue-green carapace, a fat snowy white belly, yellow hair on its legs and a pelt of hair on its golden claws.

In season, the female's roe is creamy, golden and richly aromatic, and the milt from the male is just as delicious.

All these excellent properties make the Yangcheng Lake hairy crab the crustacean of choice, and also caused its downfall.

Indiscriminate harvesting and farming in the past decimated the native crab population and polluted the waters. Aquatic plant species have disappeared, some forever.

A timely recognition of environmental threats is now slowly reversing the crisis. Crab farms are strictly limited to the eastern part of Yangcheng Lake with the rest protected by tough environmental laws.

In 2013, according to Yang Weilong, chairman of Suzhou Yangcheng Lake Hairy Crab Association, 180,000 acres(728sq km) of Yangcheng Lake was contracted to 1,000 qualified farmers.

The annual harvest of Yangcheng Lake hairy crabs hovers around 2,400 to 2,600 tons per year. National consumption each year, however, is more than 300,000 tons.

The math shows that real hairy crabs from the lake account for no more than 1 percent of the total sold.

In Shanghai alone, 300 tons of hairy crabs are eaten every day during the crab season. It means that the total harvest from Yangcheng Lake would be gone in just 8 days.

Most of the hairy crabs on the markets are "bath-tub crabs" or crabs from other areas masquerading as Yangcheng Lake originals.

The bath-tub crabs mainly come from Taihu Lake. Just before the official crab season starts, these crabs will be quietly transported to Yangcheng Lake and soaked in the lake waters for a week or two.

Some of the more unscrupulous vendors will even bleach the bellies of their crabs to meet the "snowy white" criteria.

A few years ago, the Suzhou Yangcheng Lake Hairy Crab Association started to tag its crabs. It took about a week before fake tags started selling on the Internet.

For the discerning consumer, any crab is a good crab if it is a healthy, naturally raised crustacean.

But of course there will be some who will insist on the designer label.

(China Daily 10/06/2014 page7)