An Study On The Individual Biology Of The Stream Fish Schistura Fasciolatus In Nanling

Schistura fasciolatus belongs to Cypriniformes,Cobitidae,and Schistura.Located in the north of Vietnam and the Pearl River,Han River,Jiulong River,Nanliu River,Hainan Island,the middle and upper reaches of the Yangtze River,Hong Kong and other places.Samples were collected from Nanling area of Guangdong Province.In this study,a systematic study was carried out on the population biology of Schistura fasciolatus from the aspects of age and growth,feeding characteristics and reproduction characteristics.Meanwhile,an investigation was carried out on the water quality,plankton,benthos and fish diversity in its habitat environment.In order to provide basic materials for the biological research of the family of Cobitidae,and to provide scientific basis for the protection and rational utilization of Schistura fasciolatus.The main results are as follows:1.The p H of water quality at various points basically meets the water quality standards for fishery waters published by the state.The content of dissolved oxygen is relatively high;The content of nutrient salt trinitrogen was low,organic matter was less,total nitrogen was 0.35-0.91mg/l,total phosphorus was 0.014-0.062mg/l.A total of 128species of 7 phyla of phytoplankton were detected,among which the species and quantity of Bacillariophyta,Chlorophyta and Cyanophyta were the most.There were 75 species of zooplankton belonging to four major groups,including 19 protozoas,19 copepods,16rotifers and 21 cladoceras.There were 41 species of benthos,most of which were aquatic insects.There are 38 species of fishes belonging to 29 genera,8 families and 3 orders.2.The body length of Schistura fasciolatus samples ranged from 16.46 to 83.00 mm,with an average of 53.97±10.86 mm.Body weight ranged from 0.07 to 8.70g,with a mean of 2.61±1.55g;The age distribution ranges from 2 to 6 years old.The dominant body length group was 55-65 mm,accounting for 29.84%of the total sample size.The dominant body weight group was 1.5-3 g,accounting for 35.60%of the total sample;The dominant age group was 3 years old,accounting for 42.16%of the total sample.3.By comparing four kinds of age identification materials,such as scales,otoliths,vertebras and operculums,it was found that the annual rings of radiation ditch on scales were clear and complete,and the interpretation ability was more than 95%,which was the best age identification material.4.There was no significant difference in the relationship between male and female body length and body weight（p>0.05）.The relationship between body length and body weight was W=2E-05x^2.9922R²=0.955,which was uniform growth.There was a linear relationship between body length and scale:Y=523.76x-11.83 R²=0.864.Von Bertalanffy Growth equation:Lt=155.65(1-e^{-0.1205（t+0.2527）}),Wt=72.51(1-e^{-0.1205（t+0.2527）})^2.9922.The inflorescence age of the fish was 8.84 years.The body length and body weight at the inflection point were 103.63 mm and 21.47 g.5.The analysis shows that the food is mainly covered by algae.The occurrence rate of Navicula and Melosira of Bacillariophyta is more than 90%.The feeding intensity of Schistura fasciolatus was enhanced with the increase of body length,and the feeding intensity of male was higher than that of female.Although Schistura fasciolatus was a generalized predator,the diet composition variations were low within individuals.6.In the breeding period,the mature females of Schistura fasciolatus had larger abdomen than the males,and generally did not have pearl organs on their bodies.The mature males were relatively slender,with sparse pearl organs appearing in their snout,lips,whiskers and other parts.The breeding season is June to August every year,when the ratio of females to males is 0.78.The first sexual age of female is 2 years old,spawning type is divided into batches of spawning type.The absolute fecundity of Schistura fasciolatus ranged from 389 eggs to 2778 eggs per fish,the relative fecundity ranged from 53.6/g to 545.7/g of body weight.Schistura fasciolatus has fast growth,early sexual maturation and short life cycle.They are omnivorous fish with a partial plant-eating nature;The fertility is relatively low;The habitat water quality environment is good,the bait is rich,suitable for its growth and reproduction;It is the best basis to judge the age by the characteristics of the scale radiation ditch.