With the beginning of autumn, Division of Pisciculture of the Lithuanian Fisheries Service in cooperation with the researchers from the Nature Research Centre started marking salmonids and reconstructing fish passes. Acoustic transmitters will be used for marking for the first time in Lithuania. UAB Elsis TS will supply the acoustic telemetry equipment for the project.
Previously, radio telemetry was used in Lithuania, however, this year the Fisheries Service acquired new acoustic telemetry equipment, which is becoming increasingly popular throughout the world every day. Transmitters of this type can be used in both fresh waters and seas or oceans with absolutely different salinity of water. They provide extremely accurate data. This is a new technologic step forward.
Receivers will be placed in several locations: below a fish pass to capture a fish swimming therein, also, inside a fish pass itself in order to find out how long a fish stays in it, and behind it to see how long it takes for a fish to adapt after a fish pass in the water body.
Along with acoustic receivers, internal fish markers are also used for research; they are implanted inside a fish during the operation, and send signals to receivers. 30 salmonids will be marked for research. They will be observed for three weeks.
The conducted research allows monitoring changes in population of fish in Lithuanian rivers and lakes. According to specialists, research conducted last year showed that the number of fish in Lithuanian waters has been increasing.