River Mörrumsån
Important water for salmon and mussels
River Mörrumsån which flows into Pukavik Bay, is one of the country’s most species-rich rivers. It is home to more than half of the country’s freshwater fish, such as salmon, sea trout and eel. It is also home to threatened species such as the pearl mussel and the thick-shelled mussel, as well as several bird species and otters.
Despite previous restoration efforts, challenges such as migration barriers and habitat loss remain. Ongoing and planned actions include the removal of migration barriers, habitat restoration and the restoration of 13 hectares of wetlands, bogs and fens to improve hydrology, water quality and biodiversity. Species that primarily benefit are salmon, mussels and other aquatic organisms.
In Blekinge County, River Mörrumsån is a Natura 2000 site. The river then continues up into Kronoberg and up to the source areas in the highlands of northern Scania. In total, the river extends 180 km from the mouth of the Baltic Sea up to the source areas. The catchment area is 3,360 km², and the river is regulated with a large number of, which affects the ecological status. The main influencing factors are migration barriers, habitat degradation and eutrophication.
River Mörrumsån is one of Sweden’s most species-rich rivers. Around half of Sweden’s freshwater fish species are found in the river, including salmon, which is a priority species in the conservation plan. River Mörrumsån is one of the largest producers of wild salmon in the Baltic region.
The river also has a rich invertebrate fauna, including the pearl mussel and the thick-shelled mussel, which are two of Sweden’s most endangered freshwater mussels.
Several insect species, such as red-listed mayflies and dragonflies, are present, making the river an important refuge for threatened species. Bird life is also rich, with stable populations of, for example, common tern and white-tailed godwit, and a small population of kingfisher. The otter is a priority species under the EU Habitats Directive and is included in the conservation plan.
More than half of Sweden’s freshwater fish species are found in the river
Measures to strengthen the ecosystem
Connectivity in the river needs to be improved through habitat restoration and environmental adaptations to enable migration for fish and other aquatic organisms. For example, Hackekvarn is one of the last barriers for salmon and sea trout on their way to Åsnen and further upstream. Measures here would benefit both salmonids and mussel populations.
The morphological status of the Mörrum River is affected by past gutting and damming, which has degraded the habitats of several species. Restoration measures aim to restore natural stream habitats, improve connectivity and increase water holding capacity.
The Pukaviksbukten Natura 2000 site, an important habitat for fish, birds and mussels, is located at the mouth of the Mörrum River. The area is heavily polluted with nutrients, which affects fish foraging and risks oxygen depletion and benthic mortality. To counter this, wetlands are being constructed, including one within the Improve Aquatic LIFE project focusing on nutrient retention.
Previous and ongoing projects
Several projects have been carried out in River Mörrumsån, including UC4LIFE (2012-2016) and LIFE Connects, where cleared stretches were restored and side channels in collaboration with Mörrums Kronolaxfiske. Measures to promote connectivity have been implemented at Marieberg, Hemsjö and Fridafors. Under the national plan for hydropower, 33 facilities will be environmentally adapted, including fish passage solutions and regulation changes.
In conclusion, the measures in River Mörrumsån are crucial to improve habitats, enhance biodiversity and achieve favorable conservation status for designated species and habitats within the Natura 2000 site.
Survival of river pearl mussels 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 Mörrumsån
Latest news from the project area
Here you can read news about the target species and the actions being taken in the project area.