南太平洋におけるビンナガの釣獲率の分布型について

概要

論文の詳細を見る
The frequency distribution of hooked-rate in tuna longline operation had been known already as a form of negative binomial distribution by previous authors. Here, the authors tried to find out the schooling intensity of albacore, represented by a parameter k in formula (1) of negative binomial distribution, from the data about the fishing operation in Southern Pacific, 18°-30°S and 170°E-170°W, during July to November 1955. The fishing ground was devided by a unit area of 4° square, and the hooked-rate (number of fish caught by 1000 hooks in a long line) of each operation during a certain month in a unit area was grouped to be an unit block for analysis of the authors. Among 48 blocks obtained from operation data, merely 18 blocks which has more than 40 operations data were selected for the analysis. The results of analysis are as follows. 1) Frequency distribution of the hooked-rate of albacore seems to be represented by negative binomial distribution from the results of F test of Poisson distributions divergense coefficient (formula (3)) and test of goodness of fit against the theoretical negative binomial distribution (Table 2, Column 6). 2) Values of k calculated in each blocks using the formula (2) were variable from 2.133 to 7.161 (Talbe 2, Column 10). About k, SUDA (1958) reported already 2.0-4.4 of albacore in North Pacific. 3) The authors calculated a common value of k through out 18 blocks by four methods independent from unit area and month. i) The most likelihood method ( ?? 1=3.817), ii) Nonweighted mean method ( ?? 2=4.573), iii) Mean weighted by number of sample ( ?? 3=4.435), iv) The regression coefficient method ( ?? =3.998) (formula (5)). ?? 1 is the best theoretically, but this method is troublesome to calculate. ?? 4by the regression coefficient method is easy to obtain and not so different from ?? 1 in this case. The round estimate of value for k is 4.
公益社団法人日本水産学会の論文

南太平洋におけるビンナガの釣獲率の分布型について

スポンサーリンク

概要

著者

関連論文

スポンサーリンク