Abstract
The regional variation in aquatic organisms by water region is an important topic, especially in the process of segmenting water areas to determine environment standards for the conservation of aquatic life. This study demonstrates a method to analyze the regional characteristics of freshwater fish fauna, using multivariate analysis of fish assemblage structure. Applying this method, the analysis was conducted on a total of 47 fish species recorded in field surveys and drawn from existing literature surveys conducted in the Naka River in Fukuoka, Japan, which were then classified into five groups. The factor involved in the classification were explained as the habitat altitude and the types of biological life cycle. By comparing to the indicator species provided by the Ministry of the Environment (MOE), a classified list including local species in the area was presented in which the five groups were categorized by their preferences for low-temperature zone or high-temperature zone environments. This classified list was applied to the fish distribution data for six rivers flowing into Hakata Bay. It is noted that local species were found in all of the survey sites, while the indicator species specified by the MOE were absent in some sites. This suggests that considering local species as indicator species would provide more information on the conditions of the rivers.
