| Based on the samples of Cololabis saira collected by"lupengyuanyu027" of Penglai jing lu ocean fishery company and"guoji908" of Dalian international ocean fishery company and operating in the Northwest Pacific Ocean during June to July and October to November 2014(688 pieces of statolith morphology were measured,including 133 pieces of statolith increment counting),it analysed staotolith microstructure and its growth,and using the otolith microstructure to research age and growth of Cololabis saira,analysis of the composition and change of trace elements in otolith.The main results can be found as follow:(1)In the 688 samples,the male and female ratio was 1.7:1,sexual maturity was given priority to with 1,2,and 3,body length ranged from 184 to 330 mm,and the dominant body length group was 270 to 310 mm.It is 276 mm.There is a significant correlation between body length and body weight of the saury,and its relationship is:BW=4×10-7BL3.473(2)Principal component analysis obtained four characteristic morphological parameters of TSL,MW,DL and DW.The otolith morphological characteristics can be fully described by using the length and width parameters of the tetrapod.(3)The otolith microstructure mainly includes the core area,the rear core area,the dark area,the bright area,and the peripheral area.From the core to the edge,the degree of change in the width of the striae is different.(4)The relationship between total otolith length(TSL),back area length(DL),MW),back area width(DW),and age is as follows;TSL=1.6691Age+ 1169.1(R2= 0.452,n=132)MW= 1.271Age+ 663.48(R2=0.5802,n=132)DL=414.921n(Age)-1205.7(R2= 0.4185,n=132)DW=168.981n(Age)-479.64(R2= 0.3672,n=132)There was a positive correlation between the otolith length,width,and age.There was a significant difference in the sizes of TSL,DL,MW,and DW in different age groups.With increasing age,the average TSL,MW,DL,DW increased,but at 440-500d,TSL,MW,DL were lower than 400-450d,otolith morphology did not change with age.(5)The otolith weight of the saury was positively correlated with its age.The difference between the age of the otolith and the age of the otolith was slightly different from the actual age.However,the difference between the otolith weight and the age was not significant.(6)Based on the Logistic,Von Bertalanffy and Gompertz growth model,study found the body length and weight growth model was suitable for Logistic growth model,the formula respectively were:BL=301.8104/1+e-0.0094(AgE-121.41533)(R2=0.6315,n=133)BL =150.2197/1+e-0.0134(aGE-277.3855)(R2＝0.6315,n=133)(7)A total of 47 trace elements were detected in the otolith sample of this year’s saury,and the top 8 elements were Ca(calcium),Na(sodium),Sr(strontium),Mg(magnesium),Fe(iron),and Ba.(barium),Ti(titanium),and Zn(zinc).(8)The results of variance analysis showed that there were significant differences in the content of trace elements Ba(P = 0.039)and Zn(P =0.041),and Ca(P = 0.673),Na(P = 0.211),and Sr(Sr).P = 0.308),Mg(P = 0.304),Fe(P = 0.256),and Ti(P = 0.205)did not show significant differences.(9)There was no significant difference in Mg(P=0.045)among different hatchlings of the saury,Ca(P = 0.135),Na(P = 0.341),Sr(P = 0.258),and Fe(P = 0.203).There were significant differences between Ba(P = 0.644),Ti(P = 0.512)and Zn(P = 0.611).(10)Among different otolithic otoliths,there was no significant difference in Ti content but no significant differences in Ca,Na,Sr,Mg,Fe and Ti contents.(11)Sr and Ba can be used as an environmental indicator element for the parasailing.(12)There was no significant difference in the contents of Sr and Ti in the main trace minerals of otoliths within 1 year of age and 1 year or older,and the contents of the other 6 trace elements were significantly different.Various factors such as the fish’s own physiological conditions,marine environment and other factors will affect the content of microelements in the otolith of the Pacific saury. |
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