長良川中下流における稚アユの遡上特性と遡上量調査の効率化に関する一考察

抄録

At Nagaragawa Estuary Barrage, a quantitative monitoring survey has been made on the anadromous population of juvenile ayu since about 10 years at fishways of the Estuary Barrage and in mid and down streams of Nagara River. In this paper, the migrating upstream characteristic of juvenile ayu in the Estuary Barrage fishways and the midstream area was considered, using the data of the anadromous population of juvenile ayu. In addition, a study was made on rationalization of the frequency of measurements and estimation of the total anadromous population from the anadromous population of juvenile ayu in some fishways at the Barrage. From the results of study, findings on the migrating upstream characteristic of juvenile ayu in Estuary Barrage and midstream, rationalization of the frequency of measurements and a method of estimation of the anadromous population of juvenile ayu were obtained.