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长江中游两岸绝大多数通江湖泊自20世纪50年代以来因水利工程阻隔先后失去与长江的联系而产生一系列的生态问题。我们以涨渡湖为例开展江湖阻隔后对单个湖泊鱼类资源所产生的生态影响进行研究,结果表明:江湖阻隔导致湖泊生产经营方式改变,使得野生渔业产量的比例由1949年的95%,降低到2002年的不足5%;江湖阻隔后湖泊鱼类种类由50年代约80种下降到现在的52种,其中,洄游性和流水型鱼类比重由50%下降至不足30%;迷魂阵渔获物在单位产量、个体大小上极显著(p<0.01)地高于通江湖泊,但在物种数和多样性指数上则要低得多(p<0.01)。因此,江湖阻隔对湖泊渔业具明显影响,且正导致野生鱼类资源的进一步衰退。
The vast majority of rivers and lakes on both banks of the middle reaches of the Yangtze River have had a series of ecological problems since the 1950s because they have lost their connection with the Yangtze River due to the blocking of water conservancy projects. Taking Yandu Lake as an example, we studied the ecological impact of the isolation of fish from individual lakes after the barrier between rivers and lakes. The results show that the barrier of rivers and lakes leads to the change of the mode of production and management of the lake, making the proportion of wild fishery output from 95% To less than 5% in 2002. After blocking rivers and lakes, the species of lakes dropped from about 80 species in the 1950s to the current 52 species, of which the proportion of migratory and stream-type fish dropped from 50% to less than 30% The yield was significantly higher (P <0.01) than that of Tongjiang Lake in unit yield and individual size, but much lower in species and diversity index (p <0.01). Therefore, the blocking of rivers and lakes has a significant impact on lake fisheries and is leading to the further decline of wild fish resources.