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计算自然死亡率系数,是研究鱼类捕捞群体数量变动的一项重要内容。这一系数值在估算鱼类捕捞资源量及其利用程度,拟定合理开发措施等实际工作中必不可少。考虑到自然死亡率系数随着年龄变化,因而通常采用П.В.秋凌(1972)法进行估算,系数值用图表法确定。本文试图将死亡率曲线用分析式予以表达。自然减量的系数值中与鱼类年龄t的关系,一般表现为“U”型曲线,这表明世代的最高死亡率在生命的第一年和最后几年。在计算“平均”年龄t_П(相当于性成熟年
Calculating the coefficient of natural mortality is an important part of studying changes in the number of fish fishes. The value of this coefficient is essential in the practical work of estimating the amount and utilization of fish fishing resources and formulating reasonable development measures. Taking into account the natural mortality coefficient changes with age, it is usually used V. (Ling) Ling method (1972) to estimate the value of the coefficient to determine the chart. This article attempts to express the mortality curve analytically. The relationship between the coefficient of natural reduction and the fish’s age, t, generally appears as a “U” curve, indicating that the highest mortality in the generation is in the first and last years of life. In calculating the “average” age t_П (equivalent to sexual maturity years