River Mieån
Mussel recruitment and cooperation
River Mieån flows from Lake Mien towards the Baltic Sea through a rift valley with varied terrain. The water is clear and contains both resident and migratory trout, as well as species such as sandpiper, whitefish, burbot, brook lamprey and eel. River dippers and Grey Wagtails nest along the river, and otters are scattered throughout the area.
The Freshwater pearl mussel population in River Mieån is fragmented and has been declining since the 1970s. Low densities of trout and migration barriers threaten the survival of the mussel, despite good water conditions. Thick shelled river mussel has recently been found but is also threatened by habitat degradation and barriers to host fish.
Fragmentation, clearing, draining and lake lowering affect the river
The River Mieån is heavily fragmented by dams used for mills and hydropower, which impede fish migration and affect the flow regime. Historical clearing of the river for Timber floating has concentrated the water flow and led to erosion. Drainage, wetland draining and lake lowering have reduced the river’s water holding capacity, which is also exacerbated by climate change and low summer flows.
Drainage, wetland draining and lake lowering have reduced the river’s water holding capacity
Necessary improvements
Habitats and connectivity in the river need to be improved. The entire water body needs to be addressed to create favorable conditions for species such as trout and Freshwater pearl mussel. Several Natura 2000 sites such as Loberget, Ire, Grimsmåla and Långasjönäs are covered by the work. The conservation status of important species and habitats is classified as unfavorable.
Hydromorphological action plan and long-term management plan
Within the LIFE IP project GRIP on LIFE, a hydromorphological action plan has been developed for River Mieån, which together with a long-term management plan forms the basis for further measures. The municipality of Karlshamn is actively working on the restoration of cleared stretches and the municipality of Tingsryd is participating in the management of the river. Fisheries conservation area associations run their own restoration projects, and the biosphere reserve Blekinge Archipelago implements measures in the catchment area.
The River Mieån is included in the national plan for environmental adaptation of hydropower, where six plants will be adjusted for improved connectivity.
Improve Aquatic LIFE actions
Under Improve Aquatic LIFE, wetland restoration is planned in the Ire Natura 2000 site to improve water holding capacity and increase resilience to climate change. Two migration barriers will be removed and upstream and downstream habitats will be restored to strengthen the populations of the Freshwater pearl mussel and its host fish, the brown trout.
Helping mussel recruitment to take off
As the conservation status of Freshwater pearl mussel and Thick shelled river mussel is critical, further measures are needed. The project will carry out infestation of mussel larvae on their host fish to secure future populations.
Working together to achieve favorable conservation status
The Improve Aquatic LIFE actions interact with ongoing initiatives to achieve favorable conservation status for species and habitats and the environmental quality standard good ecological status in River Mieån.
Freshwater pearl mussel survival depends on host fish
Barriers to migration
Removing migration barriers and opening up the river pearl mussel’s host fish, salmon and trout, will increase the species’ ability to reproduce. Barriers to migration come in many forms, from natural to man-made dams and power plants. In some cases, a good solution may be to build a wildlife passage to allow fish and other organisms to bypass the migration barrier.
River Mieån
Latest news from the project area
Here you can read news about the target species and the actions being taken in the project area.
