体長組成からみたシラスの生長生残過程の推定

抄録

Depending upon the analysis of the size composition drawn from catch the conditions of some exploited fish population have often been studied, and the size composition of some larval fishes may surely take hold of the revelation of their survival and growth processes in the sea. This paper treats of these matters by inspecting the size compositions drawn from the catch by the small drag net with the aid of mathematical models of a exponential function or a stochastic process.
Almost all the size composition may show the one of a cohort with the individual variation in growth though there appears the error due to the method of sampling or measurement. In the consequence of the quadratic regression application to the size composition the survival period of the cohort is detected to be about 60 days and the mortality coefficients averaged through this period have become the values within the range of 0.0250-0.0418 (1/day). The coefficients which indicate the variance of individuality in the logarithmically transformed total length have the values of ten to the minus fourth power, that are supported by the studies in another fishes rearing.