综合一区欧美国产,99国产麻豆免费精品,九九精品黄色录像,亚洲激情青青草,久久亚洲熟妇熟,中文字幕av在线播放,国产一区二区卡,九九久久国产精品,久久精品视频免费

Make me your Homepage
left corner left corner
China Daily Website

Three Gorges Dam water flow increase helps spawning

Updated: 2013-08-16 07:47
By Hou Liqiang ( China Daily)

An experiment to increase water flow from the Three Gorges Dam has helped fish to spawn and softened the negative impact of hydro plants on the ecosystem.

The experiment has been carried out by the Three Gorges Dam and Yangtze River Water Resources Commission to boost water flow since 2011.

The dam released water three times from April to June each year.

Zhao Yimin, head of the Yangtze River Fishery Resources Committee, said the move is aimed at restoring aquatic conditions downstream from the dam during the spawning period of four major types of Chinese fish.

The committee found more fish spawning after the water discharge.

According to research data from the Yangtze River Fisheries Research Institute under the Chinese Academy of Fishery Sciences, the quantity of fry from the four major types of fish in the lower reaches of the Three Gorges Dam has fallen dramatically since the reservoir began to store water.

The average number of fry passing the monitoring section each year on the Yangtze from 1997 to 2002 was 2.5 billion.

However, the quantity fell to 406 million, 339 million, 105 million and 231 million, respectively, from 2003 to 2007.

Research by the institute showed that changes in water flow and water temperature were behind the dramatic drop in the number of fish.

While spawning of the four types of fish requires a temperature of above 18 C, water flow is also needed to stimulate the spawning and to keep the spawn floating downstream and incubating at the same time.

The institute's report suggested the water level of the Three Gorges reservoir should be at least 157 meters so there would be sufficient water for spawning.

The dam needs to take the initiative to carry out the program, Zhao said.

 

 
...
Hot Topics
A sailor from British Royal Navy destroyer HMS Daring tries to catch a mooring line to dock in the north side of the bund at Huangpu River in Shanghai December 10, 2013.
...
...
读书| 诸城市| 峡江县| 望江县| 宁河县| 安吉县| 郧西县| 隆尧县| 安达市| 东宁县| 蓬莱市| 怀安县| 枣阳市| 大同市| 岗巴县| 怀宁县| 乌苏市| 林口县| 锡林浩特市| 云南省| 霍林郭勒市| 德庆县| 大姚县| 德安县| 崇仁县| 济阳县| 铁力市| 南投市| 岚皋县| 苍溪县| 普陀区| 精河县| 瑞金市| 富顺县| 枣强县| 漯河市| 盈江县| 林芝县| 平昌县| 鄂伦春自治旗| 宁武县|