| In order to understand fish fauna at Muling river,a experiment was carried out in May,July and October of 2015.This survey set up 28 sampling sites which contribute to 348 fishes totally belonging to 4 orders,5 families,21 species.Meanwhile,an investigation for local fishermen was carried out to understand the distribution of fish,which identify 45 species in Mulinghe river belonging to 5 orders,11 families.The majority is Cypriniformes(33 species)which constitute 68.69% of all 45 species.The second order is Salmoniformes(5 species)which explain 11.11%.Both Siluriformes and Cyprinodontiformes include 4 species constituting 8.89% respectively.The Petromyzoniformes only contain 1% constituting 1%.There have 41% belong to endemic freshwater fishes which are responsible for 91.11%.In this survey,the fish ecological type according to 3 kinds.Type of settlement concluded that RL、SE、SR,and living water layer concluded that P、B、D,and feeding habits concluded that F、C、O、B,and spawning type concluded that L、F、V.The fish geographical distribution shows that there are 27 kinds of fish located in the upstream,which according for 60%.7 kinds of fish located in the midstream,which according for 15.56%.And 35 kinds of fish located in the downstream,which according for 77.78%.The fish fauna components of Muling River were complex,which composed by the third age groups flora,the Northern Plains flora,the northern mountain flora,the river plain fauna,the subtropical plain flora.The dominant species are Cobitis granoci,Rostrogobio amurensisi,Cobitis lutheri,Pseudorasbora parva,Phoxinus lagowskii,Perccottus glehni,Carassius auratus gibelio,Aristichthys nobilis in Mulinghe river.The diversity of species can be analysed by the method of Shannon-Wiener and Pielou,which indicate that there have few difference in variation tread and each sampling site of these two methods.The index of Muling River showed average Shannon-Wiener to 1.97,average Pielou index to 0.36,average Maralef index to 1.16.Therefore,the fish fauna composition in Mulinghe river is stable.According to feeding habits,catchment fishes of Muling river were divided into 7 functional group: herbivores functional group,insectivores functional group,phytoplanktivore functional group,zooplanktivores functional group,benthivores functional group,omnivores functional group,piscivores functional group.The results of Canonical Analysis respected that,water environmental factors which influence fish species vary from different season.In spring,the factors are p H、Fe、TN、ORP、COD、DO.In summer,the factors are p H、Fe、TN、ORP、TD.In autumn,the factors are WT、NO2-N、NO3-N、COND.Water environmental factors which influence fish function group vary from different season.In spring,the factors are TN、ORP、p H、SD、COND.In summer,the factors are TN、ORP、p H、Fe、WT、TD.In autumn,the same as that of in summer. |
