香溪河鱼类群落组成及资源评价

THE COMPOSITION OF THE FISH COMMUNITY IN XIANGXI BAY AND RESOURCES EVALUATION

采用定置刺网的捕捞方法,于2005年3—4月在香溪河官庄坪库湾连续捕捞20次,共调查到21种鱼类。对采集的渔获物数据,分析了多样性和种群优势度。确定上层、中上层、中下层和底层的优势类群分别是贝氏、蒙古、翘嘴、鲫、鲤、蛇、鲇。三峡水库蓄水对官庄坪鱼类群落构成影响显著:鲤科鱼类种类组成比例占总种数76.2%,其中亚科有7种,占鲤科总数的43.8%。静水性生活的鱼类所占比重较大,已经形成优势种群。经济鱼类在生物量上占有举足轻重地位,上层肉食性鱼类以蒙古、翘嘴为主。鳅科鱼类基本绝迹。

Abstract This paper was based on materials of 21 species of the freshwater caught at the Guanzhuangping Bay in the Xiangxi River. These species belonged to 5 families and 17 genuses respectively. The investigation data was obtained through 20 times fishing with fixed gill nets. By analyzing the species＇ diversity and population dominance, it showed that the dominant groups of the upper layer, upper-middle layer, under-middle layer, bottom layer were Hemiculter. bleekeri, Culter mongolicus mongolicus , C . alburnus , Carassius auratus auratus , Cyprinus carpio h aematopterus, Saurogobio gymnocheilus , Silurus asotus , respectively. Three Gorges Reservoirs＇ storage has significant influence on the fish community at Guanzhuangping. The Cyprinidae fish held 76.2% of the total species, which contained 7 different kinds of Culterinae fishes, accounting for 4-3.8% of the total number of the Cyprinidae fish species. The lentic fish species held a large proportion in all species and already became the dominant species. The biomass of economic fishes also occupied a prominent position. The flesh-eater fishes of upper layer mainly include Culter mongolicus mongolicus and C. alburnus. The Cobitidae fishes almost became extinct. The constitutes of fish was occupied the absolute abvantage by the lentic or open water species in Guanzhuangping. The small and medium sized fishes take the dominant position while the big individual fishes of the upper level or medium upper level were less. The result of investigation showed that the Three Gorges dam set up in the Changjiang river changed the original envi- ronment condition of water body of the middle and low reaches of the Xiangxi river completely, and the fish community structure also took thorough changes . The original fishes had retreated to shallow rivulet above river segment of Xiakou. The advantageous groups were such minitype rheophilous fishes as Triplophysa pleekeri and Varieorhinus macrolepis. The change of water body of the Guanzhuangping Bay was more suitable for the existience of the heterophagous demersal fish of lentic or slow current species. A community mainly composed of Cyprinidac fishes. And the increase of the number of the Culterinac fishes species marked the change from the flowing water to the lentic water.