水俣市における人口推移

概要

論文の詳細を見る
Changes in population of Minamata were studied based on the data available from the national census and population registry. The results are as follows: 1) The population had drastically decreased from 1959 to 1975, and thereafter has gradually been increasing with a current population of about 37, 000. 2) The female population, especially teen-agers, has always been greater than the male population due to greater out-migration of the latter. 3) An average number of household members declined from 5 to 3.5 during 1958-1971, currently being 3.1 which has been the smallest. 4) Female population was greater in each census than the population registry in the corresponding year, while male population was larger in the latter. The difference in the population between the census and registry may be attributed particularily to the greater under-reporting among male than female. 5) Decrease in the population of Minamata after 1959 was consistent with the increased migration of the national population due to the changes of the industrial structure in Japan. The decrease is ascribed to the out-migration of the young generation for employment or education. In the following paper, we will report more detailed descriptions of these persons outmigrated from the city, particularily from the heavily polluted areas with methylmercury in order to obtain the basic information on the inhabitants to be followed up for study on the late effect of its pollution.