大型通江湖泊洞庭湖的鱼类时空格局和江湖洄游规律初探.pdf

组成上存在较大差异。渔获鱼类在丰水期最多,枯水期最少。从重量和数量相对丰度上看,丰水期主要经济鱼类有草鱼、黄颡鱼、铜鱼、鲤、鲫和蛇鮈;枯水期在重量丰度上以鲤为主,在数量丰度上则以短颌鲚、鱊和餐等小型鱼类为主。渔产量也表现出大体一致的规律,即在水位较高的月份产量较高。这一规律揭示泛滥区水体鱼类受周期性水位波动极大,这种水文扰动对丰富鱼类资源量有着积极作用。,对幼鱼入湖时间作出了推断,但尚难估计成鱼的出湖时间。总体来看,四大家鱼在洞庭湖出现时间为7-11月。四大家鱼主要分布于城陵矶和东洞庭湖,已不能到达离干流较远的南洞庭湖。根据草鱼和鲢鱼的种群动态,推测它们幼鱼的入湖时间分别为7和8月。铜鱼分2批进入洞庭湖。第一批为4-6月组,个体较大;第二批为7-11组,个体较第一批小。对江湖洄游鱼类入湖的关键时期研究表明,保持水文自然连通对补充湖泊鱼类资源、维持鱼类自然种群有着重要意义。关键词:河流-泛滥平原生态系统,洞庭湖,鱼类多样性,群落时空格局,种群动态,江湖洄游 IIIAbstract Formed by long periodically fluvial dynamics, river-floodplain ecosystem hold high habitat heterogeneity and is one of the richest biodiversity areas on the earth. The mid-lower reaches of the Yangtze River basin in China has a high biological diversity. However, in the past fifty years, the natural hydrological connectivity has impaired strongly by the construction of dams and sluices as well as reclaiming of lake to cultivated land, water pollution and overfishing. Fish resources in the Yangtze River and associated water bodies have declined seriously. Many fishes are endangered. Therefore, the studies on spatial-temporal pattern of fish assemblage and fish migration rhythms are essential to enhance our understanding of the ecological functions of hydrological connectivity gradients. Unfortunately, to date there is little work conducted on this. In the present study, a large river-connected lake, Dongting Lake, was selected as target water, a monthly investigation on fish diversity was carried out, also preliminary studies on the rhythms of fish migration were conducted in March-December, sampling areas were located along a transect from the Yangtze mainstream to the lake center, . Chenglinji, East Dongting Lake and South Dongting Lake. The main results are given as follows: 69 fish species belonging to 6 orders, 14 families and 44 genera were recorded. In terms of species number, cypriniformes was the richest in each region accounting for -% of the total. Among