河川水辺の国勢調査結果を利用した魚類および底生動物の水温·水質への依存性評価

摘要

We have analyzed the dependency of fish and aquatic invertebrates on temperature and several water quality indices using the national survey for river and riparian environment. Several species were selected and their living places have been located. Water temperature, pH, dissolved oxygen, BOD, COD, and suspended solids have been statistically analyzed to see their distribution among above mentioned locations.rnGeneralist species showed no dependency on water quality within observed variation. However, five cold water fish species showed their dependency on cold water of which annual mean maximum temperature does not exceed 26 C. Climate change, which is considered to increase atmospheric temperature may increase water temperature. It was assessed that if the water temperature rise by 1 C throughout Japan, cold water fish habitat will be reduced by 9%.%河川冰辺の国勢調査，水質データを利用することで， 魚類や底生動物の水温や水質に対する依存性を解析した. 多くの河川で確認された種については，現状の河川水質変動の中では，水質は大きな規定要因にならないことが 示唆された. ただし，冷水性の魚類などは，水温が低い 地点に限定的に生息していることが示された. このよう な生息に対する必要条件を検討する際には，水質の統計処理に留意する必要がある.