Abstract
As set-nets are a type of fixed fishing gear, the reaction of fish has great effect on the function of the gear. Fish behaviour in the salmon set-net fishing ground off the coast of Sanriku (North East region of Japan) was investigated using ascanning sonar. The research was held before and after the construction of the set-net, in order to study the influence of the set-net on the fish schools and its capturing function.
The results were that before the construction, salmon schools moved parallel to the coast with the flow of the water, however after the construction of the set-net, they left the coast at right-angles and then moved to the mouth of the set-net, owing to the leader-net. Variations of the fish behaviour related to the capturing process of the set-net were found only around the fishing gear. Salmon schools moved parallel along the edge of the floating plants for aquaculture in the same way as they behaved with the leader-net.
