Several major water-supplying rivers of Qinghai Lake have run dry due to drought and man-made development since the beginning of July, causing the mass death of a rare carp.
The fish - Gymnocypris przewalskii - are only found in the region, in their spawning migration from the lake to its tributaries.
According to Beijing-based China Meteorological Paper, tens of thousands of parent fish got stranded on the river bed of the Shaliu River, the second largest spawning ground for the carp, forming a 5 centimeter-thick "dead-fish tunnel," extending about 200 meters. It is estimated more than 500 tons of Gymnocypris przewalskii were killed by lack of water.
An expert from the local regulatory fishery body said dams and irrigation constructions were the main causes of the tragedy.
According to the expert, dams built across the Shaliu, Hairag and other rivers have cut off the routes used by the fish during their spawning migration. Obstructed, a lot of fish - approximately 500,000 each year-teem around the foot of the dams and get stranded, before dying.
To supply water to the nearby 75,000-acre farmland, a large amount of water is drained from the rivers every year. Moreover, the cultivation of grassland into farmland near Qinghai Lake and the rivers since 1960s has, over the years, caused great damage to the local ecosystem, and aggravated the water shortage by stepping up the desertification of the area.
Eighty-five percent of the 108 freshwater rivers running into Qinghai Lake have ceased to flow, and the water level of the lake has been declining at a yearly speed of 10.7 centimeters.
Excessive fishing also poses a threat to the fish resources. According to a recent report issued by the regulatory body, the amount of fish in Qinghai has been reduced by more than 90 percent, from 18 tons per square kilometer to 1.74 tons in the same unit area since the 1960s.
The increased mineral content of the water and the chemical wastes dumped into the lake and rivers have also claimed the lives of thousands of tons of mature fish, according to the report.
Biologists say the local ecosystem has already suffered from the destruction of the fish resources, and the extinction of the fish will lead to the extinction of endangered bird species who rely on the fish for food.
Measures are being taken to cope with the problem. Passageways and middle-sized reservoirs are being built to enable the fish to swim across the dams to reproduce and ensure them enough water during the dry season.
A large spawning ground has been constructed, where fish fry are raised artificially.
Fishing in Qinghai Lake and the rivers has been banned from 2001 to 2010.
To protect the local ecosystem in the long run, a program to reforest the cultivated farmland is well under way.
(China Daily 08/22/2001)
