湖南境内澧水鱼类资源现状与多样性研究

STATUS AND DIVERSITY OF FISH RESOURCES OF THE LISHUI RIVER IN HUNAN PROVINCE

作为洞庭湖一级支流，澧水对洞庭湖乃至长江水系鱼类资源的维持或补充有着重要作用。为了了解澧水的鱼类资源现状，于2010年4月～2011年12月，对湖南境内澧水水系鱼类资源进行调查。共采集鉴定鱼类95种（包括1种湖南鱼类新纪录，4种外来种），隶属于8目19科59属。种类组成以鲤科鱼类为主，占50．53％。多样性分析表明，澧水不同江段鱼类群落多样性处于较好或丰富状态，在空间分布上，鱼类物种数按上、中、下游依次增加，多样性指数也呈上升趋势且差异显著（P〈0．05）。相似性及聚类分析表明，澧水鱼类群落可分为3个类群，即：上、中、下游类群；上游与中游类群为中等相似，与下游类群为中等不相似，中游与下游类群相似性总体小于与上游类群相似性。澧水鱼类在洄游、摄食、栖息习性等生态类型上呈现多样化特征。调查江段渔获物组成虽存在差异，但主要以鲤、鲫、翘嘴鲐、蒙古鲐、鲇、黄颡鱼、餐、银绚、中华花鳅、子陵吻嘏虎鱼等湖泊定居性或山溪流水性鱼类为主，“四大家鱼”等洄游性鱼类所占比例极低，鱼类小型化现象明显，原因分析主要与水工建设和过度捕捞有关。

As one of the important reaches of the Dongting Lake maintaining a connection with the mainstream of the Yangtze River, the Lishui River is an important and valuable river for maintaining or providing the fish resource of the Dongting Lake. To evaluating the current status of fishery resource of the Lishui River in Hunan province,we surveyed the river during April to August of 2010 and September to December of 2011. 20 sampling sites were selected in the river basin including the upper reaches in Sangzhi,the middle reaches in Cili and Shimen,and the lower reaches in Lixian and Jinshi. A total of 95 fish species were collected,belonging to 8 orders, 19 families and 59 genera, Among them,one specie was new record in Hunan province and 4 species were introduced to the river basin. Cyprinids were dominant, accounting for 50.53% of the total species. Species richness and diversity index were used to analyze the characteristics of the fish communities. The results showed that the diversity and the uniformity of fish community in the Lishui River was good. On spatial distribution, the species richness increased from the upper to the lower section and the diversity indices also raised obviously. The similarity and cluster analysis showed that fish assemblages of the Lishui River could be distinguished as three cluster, upriver cluster,middle reach cluster and downriver cluster. The Jaccard similarity coefficient showed that the fish communities of the upper section were highly similar to those at the middle section, and moderately dissimilar to those at the lower section. There was higher similarity degree of the fish communities between the middle section and the upper section, and lower similarity degree between the middle section and the lower section. With regard to ecological type, fish communities in the Lishui River showed diversification types such as migratory, feeding and perching habit. Despite the species of the catches in various sections were different, the main species of the catches were lake-settlement fishes such as Cyprinus carpio , Carassius auratus , Culter alburnus , Culter mongolicus , Silurus asotus , Pelteobagrus fulvidraco , Hemiculter leucisculus , Squalidus argentatus , etc, or mountain-stream fishes such as Cobitis sinensis, Rhinogobius giurinus, etc. The ratio of migratory species such as four maior Chinese carps was extremely low, and the commercial fishes showed miniaturization significantly. These phenomena were mainly caused by the hydraulic projects and over-fishing. Some suggestions for the protection of the fish resources of the Lishui River were put forward.