User manual

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.