Statistical study on the hooked number of fish by small tonnage pole-and-line fishing boats
1987
"Hamaguchi, K. (Mie-ken. Fisheries Technical Center, Hamashima (Japan)) | Ishii, J. "
"We collected data on the numbers of Parapristipoma trilineatum and Trachurus japonicus caught daily bv pole-and-line fishing boats of 0 to 5 tons in 1984 and 1985 to find out statistical characteristics of the catches (distribution patterns and clumping indexes). As a result of the test of goodness of fit by the Chi-square test, the distributions of the catches fitted negative binomial distribution except a few cases. Therefore, we calculated the k-values of negative binomial distribution as the clumping indexes of the two species. The k-values of P. trilineatum and T. japonicus obtained by formula (1) were 0.99-1.75 and 2.51-4.16 respectively and those obtained by formula (2) were 2.18 and 4.79 respectively. But the reciprocal number of the regression coefficient shown in formula (4) could not be recognized as the k-value of T. japonicus because the coefficient was not significant with its level of significance at 0.05. We converted the data on the catches by using an area-hyperbolic sine function and a logarithmic function to stabilize fluctuations in the variance of the catches. The two conversions were found equally effective to stabilize the fluctuations, and variance and mean became statistically independent of each other, but the uniformity of variances could not be attained through the data conversions."
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