沖合水域におけるサケ・マス魚群の分布密度推定に関する一考察

概要

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In order to estimate the distribution density of salmon on the high seas, the number of tangled fish per one shackle of gill-net in one trial of test fishing by one vessel is used as an index showing the density of the salmon distribution. But the fishes tangled to the net are not necessarily distribute equally in all parts of the nets, and also it is unknown that whether or not the fish distribute equally around the test fishing area. Then the distribution of the number of fish tangled to each one shackle of one set of gill-net and the distribution of the number of fish caught by several vessels in certain limited area in the same time were studied. The results obtained from this experiment are as follows: 1. In a test fishing, at least 100 shackles (unit- “Tan” with a length about 50 meters) of gill nets must be used. 2. The probability to estimate the distribution density of salmon by the average number of tangled fish per one shackle of gill-net in one trial by one vessel is in low level. Table 1 shows that the number of fish tangled to each one shackle of one set of gill-net forms a Poisson distribution. Table 2 shows that in a round area with a radius of about 40 miles salmon population distribute a form of Poisson too.
公益社団法人日本水産学会の論文