Study On Spatial Adaptability Of Fish In Pearl River Basin Based On Morphology

The regional distribution pattern of fish space is the embodiment of fish's adaptation to the water environment.Its spatial pattern is an important content in the study of biological evolution and biogeography.The spatial pattern of fish mainly studies its distribution characteristics and laws,and it is the content of interdisciplinary interaction between ecology,biology and geography.Based on the existing literature records,FiShbase,Taiwan fish database and taxonomy related works are collected and sorted,and there are 468 pure freshwater fishes.Belonging to 5 orders 23 families.The most species(382 species),with 81.62% of the total,constitute the main part of freshwater fishes of the pearl river.In addition,siluomorpha(43 species)accounted for 9.19% of the total,followed by the siluriformes(40 species),with a total of 8.55%,and there were only 2 species and 1 species in the liguomorpha and the synbranchia.Among them,266 species of cyprinidae,56.84% of the total species,have obvious advantages in the total species.In this way,we can form a binary database of freshwater fishes in the pearl river basin and the 15 morphological and 7 ecological factor data of 74 major economic and dominant fishes in Pearl river basin.Then the weighted average method(UPGMA)number of clustering analysis(Cluster),non metric multidimensional scaling analysis(NMDS)and redundancy analysis(RDA)on the spatial distribution of the pearl river basin freshwater fish geographic distribution and morphology,ecological data analysis.And Megalobrama terminalis is put to study the morphological diversity of different geographic population concrete,discusses the mechanism of formation of the morphological diversity of different regions of Megalobrama terminalis is put,in order to provide reference for the pearl river to the development and protection of the fishery resources.The main result of this study is divided into the following three points.1.According to the distribution of different species in each area,to kind of build Bray-Curtis similarity matrix,the analysis results show that the pearl river area of 39 units,468 species of freshwater fish is divided into six groups,river delta groups respectively,and the upstream xijiang taxa,plateau lake groups,groups of dongjiang river upstream,middle and lower reaches of xijiang and beijiang river basin groups,groups of middle and lower reaches of the dongjiang river.15 major rivers in the pearl river system were selected as the analysis objects,and the richness of fish species in different regions of the pearl river was studied.Among them,Gleanson index was the largest of which was 55.23.Nanpan river,liujiang river,lianjiang river,hongshui river,liujiang,xijiang,beijiang,dongjiang and lianjiang river species richness index between 30.00-40.00,dG is relatively close.Beipan river,yu jiang,zuo jiang,he jiang,the xunjiang richness is lower.The Gleanson index is at a minimum of 11.91.To this article 15 major river fish species and abundance and the river characteristics factor of redundancy between correspondence analysis,the results showed that species richness mainly by river slope,sediment concentration,the average flow,main factors affecting river characteristics,such as long.2.15 morphological data of 74 kinds of fish group not metric multidimensional scaling analysis and weighted average method for clustering analysis,the results showed that 74 species of fish through 15 form data is divided into three groups.The group 1 of carnivorous and carnivorous omnivorous in the middle and lower layers;Active area mainly concentrated in the middle and lower groups 2 and contains a carnivorous,omnivorous,feeding the middle and upper fish groups 3,it is also a species most of fishes.The results of redundant analysis showed that the number of hypopharyngeal teeth,lateral scales,and the relative position of the orders were the most important morphological factors affecting the ecological behavior of 74 species of fishes.3 Used the traditional measuring method,morphological and framework of the pearl river basin was analyzed,and the Megalobrama terminalis put seven geographical population,the results showed that: in groups of seven Megalobrama terminalis put in morphological characters differences mainly concentrated in the lateral part of fish including: EF/body length,DE/body length,CF/body length,CE/body length,GH/body length,AC/body length,EH/body length.In addition,there were significant differences between the number of lateral scales and the number of anal fin and the other six groups in the hainan group(P<0.01).At the same time,this study proposed to combine the body length and weight curve equation of seven sites in Megalobrama terminalis province,and the value of b was smaller than that of the other six groups.This shows that the dory group in Megalobrama terminalis province is growing at a different rate,which shows that the growth rate of body length is greater than that of weight.Studies have shown that in young fish,the growth of body length can prevent the fish from being hunted by predators and increase the chances of survival,while the growth rate decreases after sexual maturity,and the weight gain is accelerated.Hainan wan quan river group is carnivorous fish less,less pressure,while the remaining six regional carnivorous fish populations and species are more,the survival pressure is bigger,this may be one of the reasons for the smaller values of the group b in hainan.