湘江航电梯级开发对四大家鱼繁殖适宜流速水域的影响

Impacts of Cascade Development of Xiangjiang River on Waters withSuitable Flow Velocity for Reproduction of Four Major Chinese Fishes

流速是影响家鱼繁殖的重要因素。以家鱼产卵场产卵适宜流速及加速度、受精适宜流速水域面积为研究内容,开展梯级开发前后典型非恒定高、低流量过程的模拟及对比。结果表明:梯级开发后四大家鱼繁殖流速水域面积变化特征显著;产卵最佳流速、产卵触发流速、产卵适宜流速、鱼卵最大受精流速和最高受精率流速水域面积在梯级开发后均大幅度缩减。梯级开发对四大家鱼繁殖流速水域面积影响不利于四大家鱼繁衍;在四大家鱼产卵适宜加速度方面,梯级开发对低流量的调控作用趋于有利(益)。本研究对以流量调控为基础开展的湘江干流航电梯级枢纽群生态联合运行调度工作提出了进一步的科学要求。

Appropriate flow rate is an important factor affecting the reproduction of domestic fish.This study focuses on determining the suitable flow velocity and acceleration for spawning in domestic fish spawning grounds,as well as the area of water with the appropriate velocity for fertilization.To achieve this,simulations and comparisons were conducted on typical non-constant high and low flow processes before and after cascade development.Results indicate a significant change in the water area suitable for the reproduction of four major Chinese carps.The optimum flow rate for spawning,the flow rate triggering spawning,the suitable flow rate for spawning,the maximum flow rate for fertilization,and the water area for maximum fertilization rate all declined drastically after the cascade development.Cascade development is unfavorable for domestic fish reproduction.However,concerning the suitable acceleration for domestic fish spawning,the regulation effect of cascade development on low flow tends to be advantageous.These findings pose further scientific requirements for the ecological joint operation and scheduling of cascades in the mainstream of the Xiangjiang River based on flow regulation.