Fish Migration Research & Monitoring Techniques

Adaptations in river basins and water management create bottlenecks for fish. Dams, hydropower plants, cooling water discharges and sluices are barriers for fish that prevent them from migrating upstream or downstream. Research into the behaviour of fish near these objects and the way they subsequently pass them is therefore very important to optimise migration routes.
Visadvies has extensive knowledge of migration behaviour and offers a wide range of monitoring techniques. Depending on the issue, the set-up is determined. To map fish behaviour in larger water systems, telemetry systems such as VEMCO or NEDAP can be used. In smaller stream systems, PIT telemetry is used. In addition, VisAdvies offers the option of following fish 3-dimensionally (3D) with acoustic transmitters (HTI tags). The behaviour of a fish at a weir, hydropower plant or cooling water discharge can thus be accurately mapped. Research is also carried out with tag-and-recapture actions. These surveys are carried out with PIT tags, Floy tags and VIE tags.


The FishCounter is used to monitor the extent of fish migration and in the evaluation of fish passages, fish locks and other technical fish migration solutions. By monitoring fish passages both ways, the efficiency can be determined.

Montoring setup

The FishCounter is mounted in a box or underwater sill. When a fish swims by, the monitoring system detect the fish's swimming direction and give an indication of its size. When a fish swims by, a short video is also recorded, allowing the fish species to be determined. The equipment is connected to the mobile 4/5g network, allowing data to be sent directly to an online database. Malfunctions can be quickly detected and remedied ensuring data quality.

Visible Implant Elastomer (VIE) Tags

Visible Implant Elastomer (VIE) Tags are colored fish marks. The elastomer is injected as a liquid that hardens into a pliable solid. The tags are implanted under clear or translucent tissue and remain visible from the outside. Implant Elastomer tags are small, flexible and biocompatible. The tag can also be used to tag crustaceans, reptiles, amphibians and small mammals.
Visible Implant Elastomer is available in 10 colors, six of which are fluorescent. Red, pink, yellow, green, orange and blue are fluorescent. Black, purple, brown and white are not. The fluorescent colors are highly visible in ambient light. Tag detection can be enhanced by using ultraviolet light. Fluorescence of tags is essential when tagging under pigmentation or for tag recovery in the dark.
VIE Tags
VIE Tags

HTI Coded Transmitter – 307kHz

The HTI coded 795 series acoustic tags are ideal for monitoring fish in freshwater. The tags operate at 307 kHz and are particularly suitable for use in high flow and high noise environments, such as around hydroelectric plants.

The tags provide an efficient means for detecting the presence of fish and/or remotely tracking fish in 2D and 3D with fine resolution up to 20 centimeters. The tags can be detected up to a kilometer away. In addition, the tags support the use of PIT tags for the detection of tagged fish outside the water or beyond the battery life of an acoustic tag.
fish migration facilities design


  • Fine-scale, sub-meter, 2D/3D resolution over time (e.g., once every second)
  • Detection ranges up to one kilometer
  • Simultaneous tag identification and detection
  • Immune to tag signal collision
  • Individual tag identification with over 500,000 unique codes
  • Multitude of tag life options (up to 5 years) with various tag size and tag life options available
  • Superior resolution and range with an encoded signal for 11 dB increase in signal strength


VEMCO offers a range of small, lightweight transmitter tags. These tags emit unique acoustic signals, allowing you as a user to precisely track fish movements using strategically deployed receivers. With VEMCO you can uncover the mysteries of fish behavior, migration patterns, and habitat use with unparalleled accuracy. VisAdvies possesses in-depth proficiency in applying VEMCO, enabling us to tailor solutions to specific requirements.

What VisAdvies can do for you:

  • Build a custom monitoring network of receivers
  • Surgically insert or attach transmitters to fish
  • Analyse fish behavior, migration patterns and habitat use
Have you become interested or would you like more information? Then please contact one of our staff members.
Ing. Hendry Vis
Ing. Hendry Vis
+31 6 41 47 09 50
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