长江中游四大家鱼产卵场的生态水文特性分析

ANALYSIS OF ECO-HYDROLOGICAL CHARACTERISTICS OF THE FOUR CHINESE FARMED CARPS' SPAWNING GROUNDS IN THE MIDDLE REACH OF THE YANGTZE RIVER

青鱼、草鱼、鲢鱼、鳙鱼是长江流域重要的经济鱼类，但近几年其资源量急剧下降，大量水利工程的修建及河道整治是导致其资源量下降的重要原因之一。为了保护四大家鱼种质资源，确定四大家鱼产卵、繁殖同水文情势的关系，为大型水利工程的生态调度提供依据，研究选取长江中游四大家鱼产卵期的9项相关生态水文指标，分析其在四大家鱼产卵场及非产卵场之间的差异。分析结果表明，所选取的9项生态水文指标在产卵场断面和非产卵场断面没有显著差异，它们只是刺激四大家鱼产卵的必要条件，而非充分条件。同时，选取葛洲坝下典型产卵场江口断面，对比分析该断面在三峡工程正式运行前后四大家鱼产卵期内生态水文情势的变化。结果表明，所选取的9项生态水文指标大多无明显差异，个别指标因三峡蓄水略有变化，但由于三峡蓄水后时间序列较短，且2004～2006年长江来水情况较为特殊，因而目前尚无法定量化三峡工程的修建对下游四大家鱼产卵场的影响。

The four Chinese farmed carps, i. e. black carp, grass carp, silver carp and bighead carp are economically important species in the Yangtze River. In the recent two or three decades, the resource abundance of these fish has abruptly declined. There are many influenced factors, in which the large-scale water control project constructing is one of the most important reasons. In order to conserve these four species and provide the basis for ecological operation of large scale water control project, nine eco hydrological indicators in the middle reach of the Yangtze River,including the flow rise number,total flow rise days,starting stream flow,increasing rate of stream flow,continuous period of rising of water level in a flood period, et al. have been used and quantitative analyzed during the breeding season. It was found,there were no significant differences between the spawning grounds and common reaches for the nine indicators. It means that the selected indicators are only the necessary conditions for the four freshwater fishes spawning,but not the whole influencing elements. After Three Gorges Project began to run in 2003, most of the selected eco-hydrological indices have no significant changes in the breeding season in Jiangkou typical spawning ground section, but the increasing rate of water level has been reduced slightly in the same section. Due to the time series data after Three Gorges Project storing water were short and the water situations of the 2004-2006 year were special,it was still unable to quantitatively analyze the influence of the four fish spawning grounds by the Three Gorges Project construction.