For the Safety Navigation In Japanese Coastal Waters page 108/120

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概要：
－6－(2) Bottom gill net fishingThe Bottom gill net fishing is a fishing method to catch fish in the bottom layer of water,and the nets are mostly fixed. Because bottom gill nets are fixed by anchors ....

－6－(2) Bottom gill net fishingThe Bottom gill net fishing is a fishing method to catch fish in the bottom layer of water,and the nets are mostly fixed. Because bottom gill nets are fixed by anchors to the seabottom, only floats and markers are seen on the sea surface. (See Fig. R-11)Fig. R-11 Bottom Gill Net Fishing(3) Drift gill net fishingWith this method, the installed position of gill nets is not fixed-they drift carried along bythe wind or tidal current. The drift gill net fishing method is designed to catch schools offish in the upper and middle layers of water.Gill nets drift along the directions of wind and tidal current, but their depth variesaccording to the species of fish sought from the sea surface to a depth of 50 to 60 metres.When a line of floats and markers are seen (at intervals of 20 to 30 cm), this indicates a driftgill net for catching surface fish, and when they are seen in a line but at greater intervals of20 to 30 metres, this indicates a drift gill net for catching fish in the lower layer or bottom.(Fig. R-12)Fig. R-12 Drift Gill Net Fishing