Abstract
In some lakes, submerged plants have been increased abnormally and have generated floating submerged plants. Several social problems have been occurred due to the submerged plants. In this study, focused on the food chain of the ecosystem in lakes, consumption experiments by using freshwater shrimp were conducted to reduce floating submerged plants. Furthermore, measurements of water quality were conducted to understand a change of water quality in the consumption experiments. Results of the consumption experiments, reduction effects of floating submerged plants by freshwater shrimp can be expected. Consumption were 0.404g-wet/g·day for Ceratophyllum demersum, 0.505g-wet/g·day for Potamogeton crispus and 0.557g-wet/g·day for Myriophyllum spicatum. Furthermore, feeding rate of water plants by freshwater shrimp was found to be larger than the fish. Consumption of water plants were low at 18 °C and 28 °C. Consumption of water plants was the largest at 25 °C. From the above, it can be expected to reduce the water plants by using freshwater shrimp when the water temperature is around 25 °C. From the results of the consumption experiments, deterioration of water quality by freshwater shrimp were less.
