Nippon Suisan Gakkaishi 70 (5), 699-705 (2004)

An application of a Bayesian model as an auxiliary method for analyzing growth

SHUHEI OHNISHI1* AND KATSUHIRO KISO2

1School of Marine Science and Technology, Tokai University, Shizuoka, Shizuoka 424-8610, 2Ishigaki Tropical Station, Seikai National Fisheries Research Institute, Fisheries Research Agency, Ishigaki, Okinawa 907-0451, Japan

Before constructing growth formulae with time-varying growth coefficient, the gain in body length should be examined using data. For this purpose, it is necessary to apply an auxiliary analysis model while constraining the fluctuation of body expansion in time. This paper presents an analysis model which has a flexible fitness for the fluctuation in length. In general, the time-varying growth coefficient has been described by a periodic function. On the contrary, we employed the first-order differences of growth coefficient, which follows the probability distribution. Here, we describe the parameter estimation and model selection based on Bayes' Theorem and Marginal Likelihood. In order to compare the result of the Bayesian approach with that given by the conventional way, we introduced the body length data of masu salmon. In a case where only unreliable growth information has been obtained, it is necessary to extract the biological characters from data, which is useful for model exploration and construction. Through the auxiliary utilization of the Bayesian model, the biological features related to the complicated mechanism of growth may be specified.


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