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2 Science Manual – Using Video Images for Fisheries Monitoring

Take the time to plan:

You may have the tools, you may have the

site, but do you have the time and

resources to devote to them to obtain the

results which the monitoring is being set

up for? Fish counter projects that fail

nearly always do so because the time

required to routinely operate them is not

planned for, or grossly underestimated.

monitoring techniques, including image analysis and motion detection, can be used

for these comparisons.

Any natural or manmade channel, fish pass, bypass, or water intake that is a

maximum of two metres wide and two metres deep can use video counting. Sections

of weir face may also be suitable.

2 Criteria for site appraisal

This section of the manual guides you through the process of choosing equipment

and deciding how to deploy and orientate it on a specific site. The section does not

compare alternative counting techniques; for more information on fish counting

methods, please see the Contacts Section.

The equipment required to monitor any

given site and its deployment

configuration will depend entirely on

the dimensions and characteristics of

the monitoring location (depth, width,

water clarity, security, power). The four

most common types of pass, Denil,

Larinier, pool and traverse and vertical

slot, have common attributes which

make it convenient to consider them

together. The width and depth can vary

widely even within fish passes of the

same type, therefore it is not possible to specify one video counting array for each

type of pass. Here, the Denil and Larinier passes have been broken down into size

categories and different systems specified.

For further advice, see the Contacts Section.

2.1 Purpose of monitoring

First, decide what your aims and objectives are for the site, as this will determine the

type of information you need to obtain from your fish counter and therefore the type

of kit needed. For example, at one site you may want to deploy a counter for a few

weeks simply to see if any fish are using the fish pass, whereas at another site you

may want to know the size and species of fish using a pass over a number of years.

2.1.1 Species ID

Detailed images may not be necessary to identify fish species at all sites. For

example, only one species may be expected to use the pass, or the species in

question may differ enough in size and form to be distinguished by their silhouette

alone. The best camera and lighting array for species identification is a sideways

camera looking across a light panel on the bed of the fish pass. However, this

configuration will not work as well as a camera looking across to a light panel on the

opposite wall in more turbid conditions; thus, the best configuration will depend on

the characteristics and priorities for the site.

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Radiant DVMD1 Manuel d'utilisateur Page 10

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