STUDIES ON THE FISHERIES OPERATING WITH AID OF LURING LIGHT-IV

In Japan, saury has been caught by stick held dip net from September to December, in the coastal sea areas of the pacific. The process of the capture of fish with stick held dip net is divided into the following three orders according to the kinds of fishing lights. First of all, saury is gathered to around of starboard being lured by fishing lights which is equipped at starboard. Generally this light is named as gathering light and composed of 13-30 white globes of 500W. Secondly, saury is removed to port side from starboard where fish has been grouping by the action of fish light which is set at port, usually this light is called as guiding light and composed of 3-7 white globes of 500W. Last of all, saury is lured into the net setting in advance into the water with aid of light, usually this light is called as catching light and composed of 3-6 red colour globes of 500W. (These data concerning the composition of fishing lights were supplied from saury fishing boats in Chiba prefecture in 1955) The results of this study will be discribed as follows; Let C is the intensity of illumination in candle power the quantity of saury gathered to starboard is proportionate to C1/2-1/4 of gathering light. When the ratio of the candle power of guiding light to that gathering light is half and less, saury is lured most effectively to port from starboard. The most suitable numbers of catching light to make saury lure into the net is composing 5-6 and less red colour globes.