Study On Conservation Biology Of Spinibarbus Sinensis

Spinibarbus sinensis,belonging to Cyprinidae,Barbinae,Spinibarbus,was ever a common fish specie which widely distributed in the upper Yangtze River.However,the population resources of S.sinensis suffered a serious collapsing due to overfishing,construction of hydropower stations,aquatic environment pollution and other human factors in the recent years.In addition,it has been restricted to conservation and management for population resources of S.sinensis due to lack of systemic data on biology.Therefore,it has been an urgent problem that how to preserve the resources of S.sinensis.In this research,which based on a long-term investigation between 2012 and2016,the conservation biology of S.sinensis was studied in the following areas:age,growth,reproduction,feeding habit,population resources assessment,morphological variation and toxicology evalution on heavy metal.Furthermore,some reasonable suggestions were proposed for conservation measures based on the current situation of the ecological environment in the upper Yangtze river basin.The main conclusions from studies follow:1.622 specimens were collected from the Chishui River between November 2012and October 2013.The wide and narrow zones appeared alternatively on the scale of S.sinensis.New annulus on the scale were mainly formed between April and June once a year.The standard length range for the female and male was 105-516 mm and 101-433mm,respectively.The estimated ages ranged from 1 to 5 years old.The length-weight relationship was:?Female?W=0.0143L^3.26,?Male?W=0.0485L^2.87,respectively.The Von Bertalanffy growth equations was:?Female?L_t=63.2^{[1-e-0.2270?t+0.3224?]},W_t=7055.0[1-e^{-0.2270?t+0.3224?}]^3.261,(Male L_t=60.8[1-e^{-0.2149?t+0.4463?}],W_t=6738.2[1-e^{-0.2149?t+0.4463?}]^2.870.The inflexion age on the growth rate curve for weight of female?male?was 4.87?4.46?years old.2.783 specimens were collected from the Chishui River between October 2015 and December 2016.The pearl organs could be observed around the snout and nose of male and few female S.sinensis in spawning season.The estimated age and standard length at first maturity stage for the females and male were 3.9 years and 388.0mm,3.0 years and320.0 mm respectively.S.sinensis,which spawned between April and June once a year,was a batch spawner estimated by gonad development stages,gonadosomatic index?GSI?and size-frequency distribution of oocytes diameter in different months.The absoluted fecundity of female S.sinensis was calculated by gonads at IV Stage,the result revealed from 19511 to 59295 eggs per fish.The relative fecundity ranged between 9.7 and 16.8eggs per gram of body weight.The fecundity increased linearly with standard length and body weight.3.405 specimens were collected from the Chishui River between October 2015 and December 2016.The monthly feeding intensity of S.sinensis varied significantly,which was at peak in two period annually,March and from September to November,respectively.S.sinensis was omnivore-fish stressing on hydrophyte based on the index of preponderance.The diet compositions of S.sinensis included algae,zooplankton,hydrophily insect,Mollusca,hydrophyte and organic detritus,thereinto,diet compositions at juvenile stage consisted of algae,zooplankton and organic detritus.The juvenile didn't feed macroinvertebrate and hydrophyte until grew to 100mm.The index of preponderance about hydrophyte maitained high level in whole year,and the peak of macroinvertebrate was in autumn and winter.Diet composition was relatively heterogenous among seasonal groups and standard length,which indicated that standard length and season were the important factor to diet composition.4.The annual population resource of S.Sinensis in Chishui section?16km²?of the Chishui River was assessed by the length based on cohort analysis?LCA?method from2013 to 2016.The results revealed that the quanity of S.Sinensis in Chishui section was255569,217468,190192 and 174365 from 2013 to 2016 in sequence.The decline of population resources and the miniaturization tendency of fishery resources was evident year by year.5.The morphological variation of the three stocks was investigated using traditional morphological?one-way analysis of variance,cluster analysis,principle component analysis,and discriminant analysis?and morphometry analysis.The three stocks of S.sineisis differed significantly for 29 morphological proportional characters.A cluster analysis indicated that the morphological characters of S.sineisis in Jialing River were most similar to S.sineisis in Chishui River.The principal component analysis yielded eight principal components with a cumulative contribution ratio of 62.93%.The discriminant analysis suggested that these three stocks could be divided.The discriminant functions of the three stocks of S.sineisis were established based on 16 morphological characters that differed significantly among the stocks.The total accuracy of discrimination of S.sineisis from the three stocks was 99.31%.It was presented that the morphological characteristics of the stock from the Jialing River were similar to the stock from the Chishui River,but there was a signifficant difference between the stock from Qingjiang River and other two stocks.6.The caculated 96h-LC₅₀0 was at 0.96mg/L,based on the mortality of S.sinensis embryos exposed to different concentration of nanoscale silver.The S.sinensis and zebrafish embryos were treated with 0.0-1.0mg/L AgNPs to investigate embryonic development.The result presented abnormal morphological and hematopoietic development,including head abnormality,vertebral flexure,haemoglobin reduction and heart rate decline.Meanwhile,the hatching rate was decreasing and the incubation time was increasing.The juvenile S.sinensis was treated with 0-1.0mg/L AgNPs for consecutive 96h,the activites of superoxide dismutase?SOD?,catalase?CAT?and glutathione peroxidase?GSH-Px?increased in the first stage,and then decreased,while the malondialdehyde?MDA?cotent kept increasing.7.Overfishing was the most direct and main factor of decline for S.sinensis population resources.Construction of the cascade hydropower stations and aquatic environment pollution could also threaten the survival of the population by deteriorating the habitat.There were some suggestion we provided for protecting the population resources of S.sinensis:firstly,the principle of ecological priority should be emphasized,and it was necessary to establish ecological compensation mechanism and natural reserves for S.sinensis population resources.Secondly,the illegal fishing gears must be forbidded,in addition,fishing intensity should be declined.Thirdly,it should be strengthened prevention and control of source pollution in rural areas along the river,and improved the agricultural ecology.Lastly,it was necessary to evaluate the risk grade of introduced spiecies before breeding.