Fish and Environment Conservation in the Three Gorges Reservoir, China
Before the TGD Project, more than 140 fish species have been recorded from the mainstream and the tributaries, including 47 endemic species in the upstream. The construction of the TGD changed the original river system, and thus can have serious effects on fish composition and diverstiy. Firstly, the huge dam cut off the way of migratory fish and the spreading of other non-migratory fish. Secondly, the TGD changed the hydraulic dynamics completely that affected the sub-habitat usage of local fish species and the distribution of their food resources.
As a consequence, the food resources changed markedly with the prosperity of phytoplankton and zooplankton due to the slowing river flow. Primitive fish habitats shrinked or even dispeared due to varied environmental factors such as water depth, turbidity, temperature, water flow and so on. This may lead to the changes of original fish compostition with an inevitable ecological succession in community structure.
In order to meet the above challenges, the government combined with ecologists and carried out a series of counter-measures: (1) setting up natural reserve and protected river section for endangered species, (2) setting up artificial breeding and stocking stations for some endemic species, (3) ensuring suitable aquatic environment for fish spawning, (4) strengthening fishery management and rectifying fish catching, (5) strengthening scientific research and implementing a long-term dynamic observation system on rare, endangered and endemic species.