網目の大きさと漁獲される魚の体重との関係からみたサケ・マス流網の適性目合

概要

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The present report is a study of the selective action of nylon gillnets for the size of salmon migrating in the North Pacific and Bering Sea. Putting L for the body length in cm, W for the body weight in g, t for the circumference at some section of the body in mm, and n and a for the constant in the following equation, the relation exists between body weight and the length of circumference at some section of body can be written as t=aW0•36, because the equation L ?? nW3•6 can provide the relation-ship between body weight and body length in salmon. When salmon gilled by the mesh of gillnets, a circular net mark appears in wide range on the surface of the body from the head to the immediate front of dorsal fin. Hence, assuming that the mesh size shows the length of the circumference where circular net mark appeared, the value of a at any section where salmon gilled by the mesh can be calculated from the data shown in Table 1. In this table the range on the body surface where salmon gilled by the mesh is divided into five gilled girth as shown in Fig. 1 for the convenience of calculation of a. Table 2 shows the value of a for each gilled girth in three species.
公益社団法人日本水産学会の論文