40,000 hairy crabs released in Yangtze

THE city government yesterday freed 40,000 hairy crabs into the mouth of Yangtze River near the Qingcaosha Reservoir, the first step in a five-year campaign to repair the ecosystem to improve the water quality in the reservoir that provides tap water for millions of residents.
The hairy crabs will help establish a complete food chain in the river to help more fish and other aquatic animals survive in the river, Zhuang Ping, deputy director of the East China Sea Fisheries Research Institute under the Chinese Academy of Fishery Sciences, told Shanghai Daily yesterday.
The released crabs, about half female and half male, will eat plankton while some of their offspring will become food for meat-eating fish higher in the food chain, said Zhuang, who is leading the water-improvement program.
"The better ecosystem the water has, the better its water quality will be," he said.
With a capacity of 438 million cubic meters, the reservoir is providing tap water to about 10 million local residents.
The government yesterday launched the restoration project with a total investment of 33.5 million yuan.
Some other fish, including Chinese sturgeons, perch and saury, that are rare in the area now will be put into the river in the future, he said.
While the water quality is quite good in the Qingcaosha Reservoir because it lies in the middle of the Yangtze River's mouth, the water's ecosystem is not ideal, Zhuang said. The area boasted about 120 aquatic species 20 years ago, but that has dropped to only 50.
The number has been decreasing in recent years because of hydraulic projects and other human activities in the upper reaches of China's longest river, said Yuan Lin, a professor with the River Mouth Research Institute of the East China Normal University.
The ecosystem should be restored to its condition of 20 years ago after the five-year project is completed, said Zhuang. He said the production of hairy crab can reach 60 tons in 2016. Almost no hairy crabs can! be foun d in the river now, he said.
About 10,000 of the crabs were marked to monitor their living habits so researchers can create better living conditions for them.
Some of the crabs are expected to swim to the Huangpu River and up into Suzhou Creek in the heart of Shanghai, also improving those ecosystems, Zhuang said.
Maritime police will patrol the mouth of the Yangtze to prevent the crabs from being caught by fishermen.