A Study of the Factors in the Natural and Social Environments Which Have an Impact on the Habitats of Gastrosteus microcephalus

Abstract

The purpose of this study was to determine factors in the natural and social environments which have an impact on the habitats of Gastrosteus microcephalus, a small-sized, endangered fresh water fish species. Changes in the habitats of this species over time were investigated through a questionnaire survey, and factors were considered from both regional and local points of view. The results of the regional survey indicated that the factors which exposed this species to extinction were the deterioration of the existing irrigation systems, such as the decrease in groundwater levels and lack of groundwater, resulting from the increase in the use of groundwater for agricultural and industrial purposes, and changes in the water levels over the seasons due to the water pipes laid for agricultural use, as well as the creation of more rice fields, which led to destruction of the habitats. The local survey showed that the physical factors required for this species to inhabit included gravel placed on the bottom of the rivers, 10 to 40-cm of river depth, and the presence of water plants. This study suggests the necessity of these physical factors for this species to survive, and the importance of eco-friendly land use and the education of residents, as well as the importance of deeper involvement in the preservation of the habitable environments of the species.