Within the action plan on river fishing, the Regional Environment Ministry or Department of Asturias is now proceeding to the setup of fish counters for the control and management of the salmon populations present in the rivers of the region.
These counters are electronic devices that include a control unit with the software, a scanner unit and a photo-tunnel with a video-camera. Normally they are set up in places where fishes swim through restricted passages, for instance in salmon scales or stops.
The scanner unit is designed as a door placed in the fish scale, its plates emit infrared light and when a fish swims through these plates, the light beams are interrupted and a fish silhouette is generated according to the fish that is crossing the unit. This silhouette is transmitted to the control unit, where a fish register is generated, including the fish image, the size, the time and date and the river temperature. In case that the counter includes also a photo-tunnel element, some photos are done (maximum 5) when the fish crosses the light beams, which makes possible the identification of the species.
With all those data a file is generated and is periodically downloaded from the control unit. Then, by means of a specific software, the information is analyzed in the office.