With this market survey, the Natural Resources Institute Finland (Luke) is surveying the market and requesting information from suppliers regarding the procurement of a multibeam sonar device for fish monitoring purposes. The new sonar device will be utilized to monitor migratory brown trout and Atlantic salmon populations in the river systems of northern Finland. The device will be located in Inari, Finland.

The sonar device will be used to count ascending and descending fish in natural river channels up to c. 60 m distances. The sonar unit should produce high-quality data and enable reliable detections and length measurements of passing individual fish. The image quality must allow counting fish even in tightly migrating schools. The sonar unit needs to be supported by suitable software for both collecting and analyzing the data. The environmental conditions at the sonar using locations are often highly demanding and hence, the performance of the sonar device needs to be excellent, and the required features of the device are rather specific:

1. High-quality sonar image: both transmitting and receiving sound beams should be focused through a movable lens for maximum image quality.

2. Adjustable sonar beam distances between c. 10-60 m.

3. Vertically (c. 3-15°) and horizontally (c. 15-30°) adjustable beam angles.

4. Adjustable transmitting frequencies allowing optimizing image quality for both short and long beam distances.

5. Installation and daily maintenance of the sonar system and data analysis must be possible for Luke personnel without external help.