Background During the 19th and 20th centuries the river Moälven, located in Örnsköldsvik in northern Sweden, was used extensively for log floating. The company responsible for the task cleared vast amounts of rocks and boulders from the riverbed. The resulting loss of habitat for fish and invertebrates was enormous. In 1868, during a severe flood, this logging activity caused the river to break a new course: a waterfall was created making it impossible for migratory fish to continue their journey. Acidification of open water has also been a problem for the conservation of biodiversity in Sweden over the last 50 years. Poor soil quality and ecosystem acidification results in continual damage unless action is taken. The project focused on the conservation of the habitats and species listed in the EU Habitats Directive connected with the (Annex I) habitat types Fennoscandian natural rivers and watercourses of plain to montane levels with Ranunculion fluitans and Callitricho-Batrachion vegetation. The key (Annex II) species are freshwater pearl mussel (Margaritifera margaritifera), otter (Lutra lutra), Atlantic salmon (Salmo salar) and bullhead (Cottus gobio). The Swedish populations of these species are of vital importance to conservation in the EU. For example, some 50% of the M. margaritifera within the EU occur in Sweden. Furthermore, Sweden and Finland hold the majority of the population of C. gobio within the EU and the Swedish population of S. salar is approximately 15% of the total EU population. The corresponding figure for L. lutra is approximately 5%. Objectives The overall objective of the project was to restore the habitat of the river Moälven to pre-industrial conditions in order to protect and to conserve the threatened species: M. margaritifera, L. lutra, S. salar and C. gobio. To meet this objective, the project focused on the following actions: 1. Work to re-connect the river for anadromous fish such as the salmon migrating up-stream from the sea to breeding grounds in fresh water. To by-pass the artificial waterfall, a stepped fishway was constructed through a tunnel. Furthermore, two aqueducts were modified/ rebuilt to assist the migratory fish. 2. Stepping up the liming activities – to approximately 430 metric tons/annum) – in order to secure near-neutral water in all seasons and avoid high levels of toxic aluminium. A new lowest acceptable pH (pH 6.3) was implemented in order to achieve water quality suitable for S. salar, M. margaritifera and S. trutta reproduction. 3. Restoring the natural state of stream reaches. A total of 43 reaches had been cleared and/or channelled to make it easier to float the logs. Much of this cleared material remained piled-up along the river bank and was put back by the project team in a more natural way. In some areas the material had been dynamited. Here, new boulders, which provide vital shelter and resting places for C. gobio and anadromous fish, were brought in from gravel pits. Degraded spawning grounds for fish and M. margaritifera were also restored. 4. Restoring population densities of host fish for M. margaritifera (S. salar and S. trutta) to levels needed to establish a reproducing population of M. margaritifera. In 1987, a reintroduction programme was launched for S. salar and S. trutta. 5. Re-connecting stream banks under bridges so that L. lutra is able to avoid hazardous road crossings. 6. Inform local landowners and other concerned stakeholders of the biological value of the river and thus increase the biological considerations in management practices. Results All of the project’s planned actions were carried out – notably, the construction of the fishway, river restoration works, re-introduction of S. salar and increased liming. Fishway A fishway was built at Sågfallet: this has enabled the salmon and other anadromous fish to migrate freely upstream to spawning grounds in Utterån. Biotope restoration Within the project period, the habitats for salmonids and other aquatic species were restored to a more natural state. In total, 42 stream reaches with a combined length of some 11 km were restored to natural conditions. Four reaches were restored in the main tributary of Moälven. A total of some 10 000 tons of large boulders were put into the river. Furthermore, in one reach, the river was redirected in order to recreate a more natural flow. In the long-term, the resulting river flow, together with restored structures, will further reshape the riverbed - recreating a more natural state with habitats for adult fish, spawning beds and nursery areas. In the Utterån tributary upstream of Sågfallet, 38 stream reaches were restored. Here, most of the historically relocated boulders and large stones were readily available for restoration measures, since they had been placed along the riverbanks in close proximity to streambeds. Spawning gravels were uncovered in order to recreate natural spawning grounds. Natural riparian zones were recreated by increasing the natural bends of the river and by opening closed side-channels and small streams. Improving fish stocks In order to establish a self-sustaining Atlantic salmon population, the stocking of fry was also carried out. In total, over 400 000 salmon fry were introduced into the river Moälven in the period 2006-2008. As the native Moälven stock was extinct, stock from the river Lögdeälven was used. (This is the nearest salmon river, and is also an ecologically similar river. This increased the possibility of a successful reintroduction of Atlantic salmon. Beside the LIFE project, the reintroduction of sea trout (S. trutta) was also performed. In total, around 56 000 sea trout fry have been introduced into the river. Higher densities of the salmonids in the river will also benefit the freshwater pearl mussel population. Liming The lakes and rivers in the Moälven drainage basin have been limed to mitigate acidification. Liming was increased when salmon was reintroduced into the river Moälven. The aim of the liming programme is to ensure that the pH-value should never drop below 6.3 in salmon waters. During the winter months, helicopters were used to spread lime on the ice on lakes. The lakes act as lime reservoirs and ensure that lime spreads further downstream into the Moälven waters, throughout the year. In Utterån, a new liming facility was installed with a capacity of 80 tons of lime. Otter actions Four otter (L. lutra) passages were built at four sites under road bridges in order to provide a safe crossing for otters and to reduce the number of deaths from traffic. In one place, fences were built to guide the otters to the safe passageway under the busy road. Finally, thanks to the fishway and to the reintroduction measures, new areas suitable for S. salar and anadromous S. trutta have been created. These are also of benefit to the pearl mussel population enabling them to successfully reproduce in the river Moälven for the first time in several decades. A population size of 100 000 individuals seems realistic, according to project forecasts. Further information on the project can be found in the project's layman report (see "Read more" section).