Priliminary Study Of Otolith In Fish Age And Growth And Fish Stock Identifying

Fish otolith is one of the most important materials in fishery science. Researchers use fish otoliths in the study of fish growth, life history inverse and population identification. In this paper, the use of fish otoliths on fish growth and population identification was studied.The research of fish age and growth is the important base for stock evaluation. We study the stock structure, age and growth characteristics of sandlance The result shows: the body length of Ammodytes personatus is 35.0mm- 180.0mm, the body weight of sandlance is1.09g-23.2g, the advantage age is 0-1. The relation of length and weight between male and female did not show significant difference (covariance analysis: F=0.700, P=0.404); relation function W=2.209×10^-6TL^3.059 (n=490,R2=0.985,p﹤0.001). Covariance analyze the total length and fork length of male and female, the result shows significant difference(F=4.497, P=0.036). Relation function of male and female is TL=0.691+1.022FL and TL=0.015+1.025FL. Fork morphology of male and female shows significant difference; but the relation of total length and body length did not show significant difference. The otolith length, otolith width and the relation of otolith weight and age show significant difference (F=6.789¹7.445, P﹤0.05). Relation function of otolith weight and age is OWt=0.672+0.534t and OWt=0.528+0.573t. The growth of male and female shows significant difference, the growth function is TL = 194.15{1-e⁽[-0.465 ( t+1.156)]}(( n = 109,R² = 0.750,P < 0.001,male) and TL = 182.65{1-e^{[-0.585 ( t+0.789)]}} ( n = 103, R² = 0.784, P < 0.001,female).The population identication method that use morphology of otolith to identify population is a new method.Morphology of otolith was applied to identify Scomberomorus niphonius stocks in Huanghai in this paper. The otoliths of them were collected in Lisi,Ganyu and Jiaonan waters and cluster-analyzed. No significant differences were found between three Lisi specimens and between Lisi and Jiaonan stocks, while siginificant differences were found between Ganyu and other two stocks for some measurments. The Euclidean distances for Lisi and other two stocks were 3.09 and 3.38, while those of the Ganyu and Jiaonan samples was 4.59. Therefore, Lisi and Jiaonan stocks had more relations than others. Otolith morphology has high effectivity for stock identification.