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Frequently Asked Questions
Is it difficult to install a Riverwatcher on an existing fishway?
No, especially not in a vertical slot fishway. The fishway ensures that most/all fish will go through the Riverwatcher.
How many Riverwatchers have been installed in rivers around the world?
Approx. 500
Can you install in weirs or traps?
Yes, in fact it works very well in places where you can gather all the fish.
You showed a custom double height system, can it be taller?
It can, there is no physical limitation to the height of the scanner, only the width between the scanner plates need to be adjusted to water turbidity.
What are the standard dimensions for measuring fish on the Riverwatcher? And, can the user set their own?
The scanner plates distance width can be adjusted. The generic setup is 40 cm wide but could be wider if the water is very clear.
How efficient is the Riverwatcher in counting fish? What if the fish have PIT Tags?
The Riverwatcher is 98% accurate counting fish. If the fish has a PIT tag it is detected with 100% accuracy.
What about algae build up, is that a problem?
Algae and/or debris buildup can affect the performance of the counter. For best results, keep the counter as clean as possible. Some sites have a lifting mechanism to access the equipment. The frequency of such maintenance depends on water characteristics but vary from every week to once per month.
What is the turbidity limit for Riverwatcher?
The turbidity limit of the IR scanner is 90 NTU. You will not see anything on a video long before that limit is reached but the Riverwatcher will count and measure each fish and provide a silhouette image.
Can you describe the difference between a infra-red system vs. video system?
These are two different optical systems. The IR system creates a curtain of beams in the water. When the fish breaks the beams, he is measured and counted. Speed and direction is also logged. The video system uses AI to detect, recognize and measure the fish.
Do you notice fish acting strange going through the tunnel?
We have seen fish getting startled if they are e.g. migrating at night in the dark and suddenly they enter the photo chamber with bright lights. To deal with this we recommend using infra-red lights during the night. It creates a black and white video but the fish will not be startled and can carry on his journey without interference.