魚個体群に於ける休重-体長関係の統計的取扱法について
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概要
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Weight-Length relationship in fish population has been dealt with the following two methods: i) Coefficient of fatness (F), F=W/L3…………………………………………(1) ii) Allometric method, W=KLa…………………………………………(2) The first method in the cofficient of fatness (F). however, involves the following limitation and inadequacy: 1) From equations (1) and (2) comes out equation (3), F=KLa-3…………………………………………(3) in equation (3), when α=3, the value of F is constant with no regard to the body-length (L). In this case, therefore, the value of F is significant. But, in case α>3 or α<3, the value of F also becomes a function of the body-length. Therefore, in latter cases, coefficient of fatness (F) is inadequate. 2) The pattern of distribution of the value of coefficient of fatness (F) depends not only on the value of _??_ but on the distribution type of body-length. Therefore, except the case when α=3 and the distribution of F-value is normal, the stochastic treatment of F-value has no significance. 3) When there are flection point and discontinuity in weight-length relationship, the method in coefficient of fatness (F) is in danger of neglecting the biological importance of those factors. Tester (1932) figured the coefficient of fatness (K) by the following equation (4), K=W/La…………………………………………(4) Tester's method is excellent because of obeing able to cover the above-mentioned limitation and inadequacy in coefficient of fatness (F), but his method with the very premise of equation (2), is so complicated and disadvantageous. In this paper, as the starting point, is employed the logarithmic form of equation (2), i.e. log W=log K+α log L. …………………………………(5) or w=k+αl………………………………………………(6) The result of stochastic analysis of allometry formula Y=BXa, or y=b+αx by the author (1951) are applied to the weight-length relationship in fish population, and the test of significancy of "slpe and positional differences" of weight-length lines is used for its comparison of two populations of "Koayu", plecoglossus altiuelis T. et. S. in Lake Biwa.
- 社団法人 日本水産学会の論文