洪湖鱼类多样性研究

根据1992～1993年洪湖鱼类资源调查,结合1959年和1982年的历史资料,分析了洪湖鱼类物种多样性和群落结构多样性的变化。结果表明,洪湖鱼类从江湖阻隔初期的湖泊定居性鱼类为主、江湖洄游性鱼类和少数河海洄游性鱼类亦有一定的产量、大型和中型鱼类占较大比例,逐渐演变成以鲫占绝大多数的“众小”局面;鱼类群落的营养结构从草食性种类的比例高达23%～35%、肉食性种类比例波动于10%～20%之间,逐渐演变成以鲫为主的杂食性鱼类占绝大多数,草食性种类基本上从湖内消失;种类组成从阻隔前的推测应不下100种演变成50余种,且实际能在洪湖生息的只有30余种;多样性指数、均匀度指数均有不同程度的降低。

Fish diversity in Honghu Lake

On the basis of fisheries resources investigations in 1992～1993 and in combing them with previous data in 1959 and 1982, the changes of fish species diversity and community structure diversity in Honghu Lake were analyzed. During the early years of blockage, the dominant fish species in Honghu Lake was lake-dwellers, and the river-lake migratory species and a few river-sea migratory species occupied certain amounts in catches. The dominants were the large and middle sized species, among which, the percentage of herbivorous species was 23%～35%, and carnivorous species around 10%～20%. In 1990s, the catches were dominated by Carassius orates, Pelteobagrus fulvidraco, Cultrichthys erythropterus and Hemiculter leucusculus, which were all small-sized ones. The majority in catches was omnivorous, and the herbivorous species almost disappeared in the lake. It was inferred that before the lake was blocked, there were over 100 fish species living in the lake, but the species reduced to about 50 species in 1990s, of which, only 30 or so could fulfill their life history in the closed lake environment. The species diversity indices and evenness were degraded to varying degrees.