AS cross-breeding and marine pollution has caused degeneration of local hairy crabs, the Shanghai Fisheries University plans to introduce 6,000 purebred Chinese hairy crabs from Holland this month to improve the quality of local species.
These hairy crabs, weighing one ton in total, will be brought over when they reach sexual maturity. The ratio between female and male crabs will be 3:1.
The "overseas" crabs belong to the Yangtze crustacean species, one of the three major varieties of Chinese hairy crabs -- Yangtze, Liao (from the northern provinces) and Ou (from the south).
Wang Wu, a professor at the university, said the Dutch crabs are making a homecoming trip to Shanghai. "These crabs actually originated in China. After living for nearly 90 years on foreign shores, they are now returning home."
The hairy crabs, a specialty of the Yangtze River, were first found in the Rhine within the Dutch-German border around 1912. Experts speculate that the baby crabs were carried to the Netherlands with the ballast water in the foreign ships anchored at the Yangtze's mouth.
Ballast water is poured into the ship's compartments as a counter-weight to maintain stability when it is cruising through oceans. It's common for ships to intake water in one country and discharge it in another country, where they anchor.
The hairy crabs found a similar ecological environment as their home in the Rhine, where, too, the freshwater and seawater join at the mouth of the river.
Because Europeans don't fancy eating crabs, the species multiplied quickly in the unpolluted water. Each of them can grow to more than 200 grams in weight. They have since become a delicacy for the Chinese living in Holland and are sold for just 20 yuan (US$2.4) per 500 grams.
To keep the species pure, local experts will breed them in a secluded, man-made environment that imitates the wild conditions at the university, in Jiangsu Province and on Chongming Island.
Experts believe that the 6,000 crabs can incubate 10 million baby crabs.
"Though living 'abroad' for such a long period, these hairy crabs are even more purebred than local crabs because they won't crossbreed with the Dutch crabs in the wild," Wang said, adding they have some clear Yangtze crabs features: cyan-color shell, white navel and golden claws.
(Eastday.com, November 2, 2002)
