Study On Age,Growth And Otolith Microchemistry Of Crucian Carp In Taihu Lake

Crucian carp is an important wild fishery resource in Taihu Lake.At home and abroad,the research on crucian carp mainly involves reproduction,feeding,growth and other aspects,but there is no comparison and summary of the research on the diet and biological status of freshwater crucian carp in China.The research on otolith microchemistry is relatively blank.In order to further explore the otolith and body growth of crucian carp in Taihu Lake,based on the wild crucian carp samples collected in Taihu Lake,the basic biology,otolith morphological characteristics,otolith age,growth and microchemistry were studied.The main conclusions are as follows:1.Basal biology:?1?The relationship between body length and body weight of crucian carp was fitted with the relationship formula w=a L^b.The relationship formula of female crucian carp was w=8×10^-5L^2.8101;the relationship formula of male crucian carp was w=9×10^-5L^2.7968;the overall relationship formula of crucian carp was w=8×10^-5L^2.829;the fitting function b<3,crucian carp of Taihu was in a state of negative allometric growth.2.Otolith morphology:?1?There was no significant difference in the total length,perimeter,area,wing length of asteriscus,total length,width and perimeter of lapillus?P>0.05?,and there was significant difference in the width,Rostrum Length and area of the otoliths?P<0.05?;there was no significant difference in the four morphological parameters of the otoliths?P>0.05?between male and female individuals,and there was significant difference in the other parameters of the otoliths except the Rostrum Length between male and female groups?p<0.05?.?2?Through principal component analysis,the total length,width,area and wing length of asteriscus,and the total length,width and area of lapillus can be used as representative parameters to describe the morphological characteristics of otolith of crucian carp in Taihu Lake.3.Otolith age and growth:?1?123 pairs of otoliths of Taihu crucian carp were obtained and age identified,including 36 females and 78 males.In addition,8 males and females were not identified.Six age groups were identified.The growth index of female population was higher before the first age,and that of male was higher before the second age.The growth rate of female population was higher than that of male The highest growth indexeswere 13.74%and 14.18%at the first age,the highest body weight relative growth rate was 35.53%at the second age,and the largest indexes were22.01%,69.39%and 21.09%at the first age.?2?power function fited the body length and otolith radius of crucian carp in Taihu Lake,the result shows that the fitting degree of power function is the highest,the fitting equation of body length and otolith radius is y=0.0443x^0.8686,R²=0.6741.?3?After one-way covariance analysis,there was no difference in the relationship between body length and age?F=0.129,P=0.72>0.05?.Logistic,Gompertz and von Bertalanffy growth models were used to fit the relationship between body length and age.According to AIC test,VB growth equation is suitable to describe the growth of crucian carp in Taihu Lake.The growth equation fitted by von Bertalanffy is:L_t=16.556(1-e^-0.3468?T+3.0769?),W_t=151.546(1-e^-0.3468?T+3.0769?)^2.829.4.Otolith microchemistry:?1?54 elements were detected in the otolith core of crucian carp by LAICP-MS.the normal distribution of 14 elements was found.Among them,the top ten elements were Ca?393804.27±1649.97ppm?,Na?2327.05±253.31ppm?,Sr?1155.57±112.20ppm?,K?1050.15±143.78ppm?,Fe?208.73±21.48ppm?,Ba?156.69±51.74ppm?,B?3.36±2.16ppm?,Al?0.60±0.68ppm?,Sn?0.54±0.37ppm?,Rb?0.32±0.08ppm?.According to ANOVA test,there was no significant difference between male and female crucian carp otolith core elements,that is,P>0.05.?2?The edge elements of 20 samples of crucian carp otolith were analyzed.The results showed that 13 elements were normal.Among the 13 elements,the top ten elements were Ca?394344.39±1058.66ppm?,Na?2454.11±475.95ppm?,Sr?1056.57±157.75ppm?,K?804.88±154.60ppm?,Fe?208.95±19.27ppm?,B?2.57±2.02ppm?,Al?1.44±2.14ppm??Sn?0.51±0.36ppm??Rb?0.22±0.09ppm??Cu?0.13±0.10ppm??According to the ANOVA test,there was no significant difference in the otolith edge elements between male and female crucian carp?P>0.05?.?3?According to the single factor ANOVA test,the difference of Ca and Cu in the core area is significant,that is,P<0.05,the difference of other elements is not significant,that is,P>0.05;the difference of K and Rb in the edge area is significant,that is,P<0.05,the difference of other elements is not significant Significant,P>0.05.