摘要 |
The counter has detectors placed in a flattened duct connecting an upper basin to a lower basin, and has the bottom of the duct raised so that the level of water passing over it is low. The fish passing through the duct are spread in a single layer over the opto-electronic counters distributed over the duct area. The opto-electronic detectors consist of an emitter and receiver pair, which are coupled when there is no fish present and decoupled when a passing fish obscures the light. The detectors drive an electronic counter which continuously updates and displays the count of fish passing the detectors. |