CCTV Verification of Counters

With any fish counter it is important to know its level of accuracy at different times of the year and under a range of different river conditions. CCTV systems are often installed to verify that fish counts on a river are accurate. Where video verification is used to monitor a counters performance faults can rapidly be detected.

Underwater Camera
Salmon entering this fish pass must swim through a tube where they are logged by a counter and recorded by a CCTV system. The information logged by the counter can be overlaid on the recorded footage, this allows straight-forward verification of fish movements.

Overhead Camera
For wider fish passes and open weirs cameras can be sited over-head to provide complete weir coverage. If verification is required from several separate weirs, cameras in conjunction with a multiplexor unit can be used to record footage from all cameras to a single tape.

Underwater Units
Underwater cameras, positioned correctly, have the advantage of providing close-up images of passing fish. However, when water becomes turbid, images of fish can become obscured. Where units require maintenance or cleaning, underwater cameras are fixed to hinged frames, the camera can then be easily raised from the water, even during flood conditions.

Overhead Units
Overhead units have the advantage of easy access under flood conditions, however, these can be more prone to tampering. As there is broad range of overhead cameras and lenses available units can be custom built for any specific site.

Wide-angle Underwater
Where hydroacoustic counters are installed, an array of cameras are usually placed on the river bed. To allow better coverage of open rivers wide-angle cameras can be installed.

Recessed Cameras
Under certain conditions, if cameras are at risk of damage from debris passing downstream they can be recessed into the side-walls or base of a fish pass.

Miniature Cameras
The latest CCTV installations incorporate miniature, underwater cameras. These measure only 4.5 cm cubed so are ideal for installation in locations where space is restricted. Overhead, these cameras have the added advantage of being extremely discrete.