Studies on the Behaviour of fish Schools in the Main-net of a Large Scale Set-net using Scanning Sonar - II - The Behaviour of Large Schools of Sardine, Sardinops mwlanosticta in and around the Set-net -

소나 관찰에 의한 대형정치강내 어군행동의 연구 - II - 정치망내외에서 정어리대형군의 행동 -

  • Published : 1995.03.01

Abstract

The behaviour of large school of sardine Sardinops melanosticta in and around the set-net were analyzed from sonar image recordings. The survey was conducted at Kishihata set-net in Japan from January 29th to February 22th 1992. The results obtained are summarized as follows ; 1. When large schools of sardine moved along the outside of the set-net. the shape of the school gradually changed, that was the front part extended forward in the direction of movement and the rear part concentrated in the same direction such that the school retained its original shape. 2. When large school of sardine entered the main-net of the set-net. the school was decentralized directly to the slope-net. to the central part. and to the opposite side, and then the fish school was concentrated as it moved directly to the slope-net. 3. When the size of the front part of the fish school enlarged. the maximum recorded moving speeds were 176cm/sec and 277cm/sec for schools inside and outside the set-net, respectively.

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