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4 Science Manual – Using Video Images for Fisheries Monitoring

2.2.4 Equipment housing

At some sites, you may be lucky enough to have a gauging station hut or similar in

which to store recording hardware. On other sites there may be no sheltered storage

and you will have to install your own cabinet or hut (for supplier information, see

Section 3.1). Bear in mind the location of the site and the likelihood of vandalism, as

this will affect the material you choose and where you decide to locate the housing.

2.3 River characteristics

Rivers vary widely in flow characteristics and turbidity, which affect the quality of the

images you obtain and will influence how you design the video counting system. For

example, a camera looking sideways with a light panel fixed to the opposite side of

the fish pass will work better in turbid conditions than a camera looking over a light

panel on the bed of the pass. However, the latter system will provide you with more

information in the image to help with speciation.

Other site-specific features to watch out for are whether the area acts as a debris

trap for all of the flotsam coming down the river, or whether the water is very

turbulent. In both cases it is advisable to find another site or, if possible, to address

the problem, for example by using debris booms or by removing the cause of the

turbulence.

2.4 Cost

Video monitoring systems are the cheapest tools available for counting fish in passes

and channels, but systems can range in price depending on the components

selected. Costs increase as the width of the pass increases, mainly due to the cost

of lighting the area. Infrared lamps or illuminators are a slightly cheaper, though less

even method of illuminating the counting site than light panels; however, image

quality may not be as good and may not work as well with the image processing

tools.

The approximate cost bands in the selection matrix (Table 2.1) do not include

provision for installing a mains power supply or a method of continually charging

batteries on site.

2.5 Incorporating video counting into a fish pass

2.5.1 New passes

Appendix 1 provides the design specifications for the head of a fish pass. The

features detailed in this can be included at the design stage of fish pass construction

and the costs, which are a mere fraction of the total build costs, budgeted for at an

early stage.

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Radiant DVMD1 Bedienungsanleitung Seite 12