道東沖マイワシ漁況のファジィ推論による予測

概要

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The aim of this study is to apply fuzzy rule-based inference to forecasts of the sardine catch off the coast of southern Hokkaido. The data used are the catch for age a, in year t, Ca, t, by a purse seine fishery off Southern Hokkaido from 1973 to 1989. Population sizes by age and year, Na, t, are estimated from the data using a cohort analysis. Four variables, Na-2, t-2, Na-1, t-1, Ca-2, t-2, and Ca-1, t-1, are used as the antecedent, and one variable, Ca, t, from 1981 to 1989 are inferred according to 75 fuzzy rules. The forecasting was good except for the years 1983 and 1985. The results for 4-year-old were especially good. The results are vital to the values of fishing mortality coefficient for the oldest age-class and the natural mor-tality coefficient that are needed in the application of cohort analysis. In addition, this study can involve some information on enviroments. Incorporation of environmental factors in the antecedent may improve the accuracy of forecasts.
日本水産學會の論文