コクチバスとオオクチバスの成長における流水と水温の影響  [in Japanese] Effects of water flow and water temperature on the growth of smallmouth bass Micropterus dolomieu and largemouth bass M. salmoides  [in Japanese]

コクチバスとオオクチバスの成長に対する流水と水温の影響を実験的に検討した。給餌下では,両種ともに流水池と止水池との間で成長率に有意差は認められなかった。しかし,オオクチバスに対するコクチバスの成長比は,水温の低い時期に大きかった。無給餌下では,オオクチバスの体重の減少率は止水池に比べて流水池において大きかったが,コクチバスでは両池の間で体重の減少率に有意差は認められなかった。以上の結果は,コクチバスのほうがオオクチバスに比べて,流水と低水温に対する適応能力において優れていることを示している。

The effects of water flow and water temperature on the growth of smallmouth bass Micropterus dolomieu and largemouth bass M.salmoides were examined during 14-day replicate trials in artificial ponds between July and September 2001. No significant difference was observed in the specific growth rate in body weight of both smallmouth bass and largemouth bass between the ponds with water flowing and those without water flowing when prey fish were given. The ratio of growth rate of smallmouth bass to largemouth bass was significantly larger in the experimental periods when the water temperature in the ponds was relatively low (21.5-24.0℃). When no prey fish was given, largemouth bass showed a significantly larger reduction in the growth rate in ponds with water flowing, although no significant difference was observed in the growth rate of smallmouth bass between the ponds with water flowing and those without water flowing. The results show that smallmouth bass has a relatively higher adaptability to water flow and low water temperature than largemouth bass.