Otolith Chemistry Reveals Fine Population Structure Of Bohai、Yellow Sea And Eastern China Sea In The Migratory Japanese Spanish Mackerel (Scomberomorus Niphonius)

Otoliths of teleost fishes are small, calcareous structures locatedwithin the inner ear, whose primary function is the detection of sound andmaintenance of the body equilibrium. Otolith is acellular and metabolicinertness, therefore, the chemical element from the water environmentdeposited in the otolith basically is permanent. So, the distributivecharacters of the chemistry element form otolith core to the edge recordedthe environmental（Such as temperature and chemical environment）change from the birth to capture according to the age sequence. Based onotoliths collected from the recent research programs such as “908” specialproject of State Oceanic Administration of People’s Republic of China,National Basic Research Program of China (973program)(No.2005CB422306), etc., the concentrations of fifteen elements(K、Ca、Na、Mg、Sr、Pb、Ba、Mn、Co、Zn、Fe、V、Al、Ni、Cu) in the otolithsof Scomberomorus niphonius collected from four locations weremeasured by ICPMS. The aim of this study were to evaluate thedifferences in otolith chemistry for fish collected at four locations, identify the different stocks of Scomberomorus niphonius and inspect thereliability of using otolith microchemical analysis for stockidentification， provide basic information and reference for therelationship of Scomberomorus niphonius in the spawning grounds andwintering grounds，and it was favorable to the resource protection andsustainable utilization. The main findings were as follows:(1) Regression analysis on body length and otolith weight indicatedthat there was no relevant ralationshhip between them for samples.(2)Differences between male and female were tested by ANOVA, inorder to analyze the effect of the physiological status and development tothe otolith elements. The result showed that there was no significantdifference between male and female(p>0.05)。(3) Comparing the ratios of elements/Ca of otoliths among thelocations, there was no significant differences for Na/Ca、Mg/Ca、Sr/Caand Ba/Ca; and significant differences existed for Al/Ca、Pb/Ca、Zn/Caand V/Ca.(4) According to the result of Cluster analysis，we divided the fourstocks into three categories： the northern Yellow Sea spawning groundsstokcs(NYSG)and Bohai Sea spawning grounds stocks(BSG) had highersimilarity than others； southern Yellow Sea spawning groundsstocks(SYSG) and wintering grounds stocks in the East China Sea(EWG)were independent relatively.(5) The discriminant analysis showed that total of66.7%of the samples were accurately classified for the stocks with the classificationaccuracies ranged from44.4%to88.9%relatively. The samples of NYSGand BSG was easily classified to each other and the classificationaccuracies was33.3%and44.4%，in addition，one NYSG fish wasclassified to SYSG and one BSG fish was classified to EWG；Theclassification accuracies of EWG was77.8%，there were two sampleswere classified to SYSG and NYSG；The classification accuracies ofSYSG was88.9%，there was one sample classified to BSG.