240 EIGHTH PACIFIC SCIENCE CONGRESS 



preys. These intermediate forms may be arranged as follows:— higher 

 primary predators being regulated more strongly by light than by theii 

 preys— secondary predators being regulated by both factors almost equal- 

 ly—tertiary predators being regulated mainly by their preys, though 

 being affected also by light in some degree. Thus the effect of the 

 light differs considerably according to the situations of the object fishes 

 in the ecosystem. The purse seining at Harima nada and the anchovy 

 fisheries at Ejima are the extreme instances using the light to allure 

 the fishes directly to the lamp by phototaxis; and the gray rock cod 

 fisheries at Murotsu is an extreme example using the light to gather the 

 preys of the object fishes. 



The coactions in lamp-communities are strongly affected by the 

 fish fauna, habits of animals and the environmental relations in the 

 area; consequently they may be accepted as the reproduction of the 

 coactions of these ecological factors, which are regulating the cosmos 

 of the area spatially and at all times, and in a short time in a limiting 

 area. Thus, the investigation of the lamp-communities seems appro- 

 priate to recommend as one of the most convenient methods of observ- 

 ing the coaction of animals in the natural condition in a certain area. 



