鱼类的重量-身体维数关系的研究

A STUDY ON THE RELATIONSHIP BETWEEN BODY WEIGHT AND BODY DIMENSIONS IN FISH

  • 摘要: 在运用一元数学公式:W=alb(或W=aLb)来描述鱼类的重量与身体维数关系时存在许多缺陷。作者从确立一条模式鱼的边界曲线方程出发,应用求旋转体体积的方法建立了鱼类重量与长度、体高的多元数学公式: W=alb1Hb2(或W=aLb1Hb2),并推演出鱼类重量与长度、体高、体周长之间的另外两种关系式: W=alb1Sb3(或W=aLb1Sb3) 和W=alb1Hb2Sb3(或W=aLb1Hb2Sb3)。上述几类多元数学公式在用来拟合白鲢、翘嘴红鲌和长春鳊种群及它们的不同生长阶段的观测数据时,都比一元数学公式更接近于实际情况,由多元数学公式进行预报的精度也比一元数学公式高。多元数学公式之所以优于一元数学公式是因为多元数学公式能够较全面地反映不同维数对鱼体重量的综合影响。对于不同体形的鱼类,不同维数对重量影响的程度是不同的,因此在应用时应有所选择。从多元数学公式的组成及应用情况看,真正有使用价值的是考虑了体周长的二元数学公式。由于体高易于测量,为此考虑了体高的二元数学公式更具有实用价值。作者建议,在鱼类生长的理论与应用研究中,可采用: W=alb1Hb2(或W=aLb1Hb2) 和W=alb1Sb3(或W=aLb1Sb3) 来描述鱼类的重量与身体维数之间的关系。

     

    Abstract: The formula W=a lb (or W=a Lb), though widely recognized to be reflecting the relationship between body weight and body dimensions in growth studies of fish, does have its limitation. Proceeding from setting a boundary curve equation for a model fish and making use of the method for determining the volume of a rotating object, the authors established a multivariate formula for body weight, length, and height: W= a lb1 Hb2 (or W=a Lb1 Hb2), and from which two other formulae have been derived, i. e., W=a lb1 Sb3 (or aLb1Sb3 and W=alb1Hb2Sb3 (or W=aLb1Hb2Sb3), in which W stands for body weight, L for total length, 1 for standard length, H for body depth, S for girth of fish, and b1, b2, b3 for partial indices.When checked with actual measurement of the population of Hypophthalmichthys molitrix, Erythroculter ilishaeformis and Parabramis pekinensis, including their various stages of growth, the multivariate formula gives better agreement with the data of actual measurement than does the unary form.That the multivariate formulae can give better results is due to the fact that they reflect more comprehensively the effect of various dimensions on the weight of fish.For fishes of divergent body forms, the extent to which the various dimensions affect the body weight is different, hence there should be some choice from among these dimensions when applied.Since the body depth of a fish is easier to measure than is the girth, the binary formula involving body length and body depth is of more practical interest.To sum up, the authors recommend the use of the formulae W=alb1Hb2 (or W=aLb1Hb2) and W=alb1Sb3 (or W=a L b1Sb2) in describing the relationship between dody weight and body dimensions in theoretical or applied studies of fish growth.

     

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