Within the Improve Aquatic LIFE project, a comprehensive study of fish migration using Passive Integrated Transponders (PIT) tags is being carried out. The aim of the study is to better understand how migratory fish species are affected by river restoration measures. By tracking fish movements, we can evaluate the impact of measures such as removing migration barriers, restoring natural stream habitats and improving water quality.
How does PIT-tag technology work?
PIT-tags are small electronic devices that act as individual ID tags for fish. They are implanted under the skin of the fish and transmit a unique code when they pass specific receivers. The technology is used to:
- Tracking the movements of fish
- Study how they are affected by restoration measures
- Measuring survival and return to nursery and spawning grounds
Where is the study taking place?
Fieldwork is carried out in four priority river basins:
- Rönneå River (Bäljaneå River, Klövabäcken River and Rössjeholmså River)
- Kävlingeån River
- Örekilsälven River
- Lärjeån River and Fämtan River (Göta River)
In each area, around 1000 fish per target watercourse are tagged, mainly Atlantic salmon and sea trout, which are important indicator species for the river ecosystem. To capture their movements, stationary antennas (receivers of PIT-tag signals) are placed in the target streams. In addition, portable antennae are used to detect tagged fish in specific stretches.
Why is the study important?
The PIT-tag study provides important information on how fish move through waterways and how they are affected by environmental changes and human interventions. Through this research we can:
- Evaluate the impact of measures to restore free migration routes – By studying the passage of fish past previous migration barriers, we can measure the effectiveness of our interventions.
- Improving fish habitats – By analyzing where fish prefer to be, we can target restoration efforts to the right areas.
- Contributing to EU environmental objectives – The study supports the EU’s objective of restoring 25,000 km of clean waterways by 2030, which is part of the Biodiversity Strategy.
- Strengthening stocks of threatened species – By improving habitats and migration opportunities, we can help protect and rebuild populations of salmon, trout and other migratory fish species.
Next steps
The collected data will be analyzed continuously during the project and the results will be used to improve future water management efforts. We look forward to sharing our results and insights throughout the project!