Study On The Classification And Community Ecology Of Cobitidae Of Diplostomidae In The In Irtysh River

The Irtysh River(China Section)is the only international river pouring into the Arctic Ocean System,plenty of cold water fish are bred in it,of which the small and bottom habitat Cobitidae fish widely distributed.This paper is order to research on Cobitidae,using fish parasite conventional investigation method,combing morphology and molecular biology technology,and community ecology relative parameter were analyzed.Identification,species composition,community structure and infracommunity species relationship of Diplostomidae parasitized in Cobitidae were studied.The results are as follows:(1)Field investigation of Cobitidae eyes’ parasites were carried out during 2014.7 and 2017.10 in the Irtysh River,combined morphological and molecular biological methods for identification species,measurement,description and drawing morphology figures of unidentified species,whose partial ITS1-5.8S-ITS2 sequences were alignment in Gen Bank,and using Neighbor jointing constructed phylogenetic tree.The parasites were identified as Diplostomum mergi,Diplostomum spathaceum,Diplostomum pseudospathaceum and Tylodelphys cerebralis,and Tylodelphys cerebralis is a new record of Diplostomidae in China.(2)Using the methods of community ecology statistics and cluster analysis to master the infection status and community structure of Diplostomidae in Cobitidae.The highest infection intensity was 357 for1 tail of Triplophysa strauchii.Barbatula barbatula nuda species were abundant,with community diversity and evenness index keeping high,the community structure of Barbatula barbatula nuda was the most stable in three kinds of parasites communities.The community structures of Triplophysa strauchii and Triplophysa minuta were very similar,however,the community structures of Barbatula barbatula and Triplophysa minuta was lightly similar,indicating that there were difference among host parasites communities.A linear regression model between host and parasite was established,there were a significant positive correlation between the parasitic and host body length(P<0.01),indicating that the parasitism of Diplostomidae was a cumulative effect.Three kinds parasites communities analyzed by cluster analysis,which were clustered into 2 groups:(1)Triplophysa strauchii parasite community and Triplophysa minuta parasite community;(2)Barbatula barbatula nuda parasite community.(3)Analyzing infection situation and community characteristics of Triplophysa sp.Parasites.,the results showed that 5 species of parasites were detected out including Capillaria sp.,Ligula sp.,Diplostomum mergi,Tylodelphys cerebralis and Diplostomum pseudospathaceum,three kinds of Diplostomidae of which were community dominant species,and the total infection rate,the mean infection intensity,the mean infection abundance,community diversity index,evenness index,the ecological dominance index were 18.90%,1.30±2.98,0.55±1.72,1.0297,0.9373,0.3800,respectively,and species diversity and richness index were low.Left and right community structure’s ecological dominance index were lower than the community diversity index,and the community similarity index was 0.8369,indicating that the two parasites communities structures were the most similarity and reasonable.Right community structure was more stable than left,and there were no significant difference(P>0.05)between the left and right infection intensity paired sample test,which indicated that Diplostomidae parasites had no selectivity to host eyes.