| 摘要 |
PURPOSE:To collect zooplankton harmful to fishes living in a pond or a fish breeding basin without imparting side effect to said fishes, by filtering the water of the pond or fish living in a breeding basin by a filter with a mesh size of 50-120mu. CONSTITUTION:The main body 1 of a plankton collector is constituted by covering the outside peripheral surface of a hollow skeletal body 2 with a filter 3 comprising a net with a mesh size of 50-120mu. In order to collect zooplankton of sewage, sewage is pumped up from a basin A by a pump 6 to be introduced into the plankton collector 1 under pressure through a sewage supply pipe 6 and the zooplankton in sewage is collected by the filter 3 when the sewage is passed from the interior of the filter 3 to the outside while purified water is discharged to the basin. As a result, because the mesh size is 50-120mu, plankton and bacteria useful for fishes pass through without stopping and only harmful zooplankton such as Lernaediae, parasitic on fishes, is removed.
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