シラウオ稚魚の石狩川本流から三日月湖への移動機構解明のためのボックスモデル・シミュレーション

抄録

Numerical simulation was conducted to confirm two types of immigration mechanism of juvenile Shirauo Salangichthys microdon to the oxbow lake through the Shibi Canal in the Ishikari River system. These mechanisms were consisted of three swimming behaviors of fish based on our survey in July 1995, 1996, and 1997. These behaviors, (1) coming near the bank during the ebb tide, (2) moving away from the bank during the flood tide and (3) staying around the mouth of the canal in the main stream of Ishikari River during ebb tide, were taken into the numerical simulation. Other passive movements of fish were dependent on the water circulation. Through the calculation, some characteristics shown in the field survey were produced appropriately. It was suggested that staying around the mouth of the canal in the stream of Ishikari River during the ebb tide was more efficient to move to the oxbow lake.