Freshwater Fisheries Research Division, National Research Institute of Fisheries Science, Fisheries Research Agency, Nikko, Tochigi 321-1661, Japan
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°C). 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.