Restoration of freshwater pearl mussel populations with new methods (2011–2014)
The main goal in this Finnish-Norwegian-Swedish project was to develop the co-operation between Nordic authorities and research institutes for the conservation of freshwater pearl mussel (later FPM). Moreover, we aimed to develop new methods for restoration of the declined and non-recruiting mussel populations.
An important part of the project was to provide updated information on the conservation and management of freshwater pearl mussel populations for those target groups who are involved with the management of river environment or whose decisions or activities may influence on the state of the rivers. These goals were carried out by the following activities:
The Nordic co-operation for the conservation of FPM populations was widened by taking into the co-operation new organizations involved with the monitoring and research of FPM and deepened by taking concrete common actions for restoring the FPM populations.
2. Analyses of the state of the freshwater pearl mussel populations and their habitats
The state of the FPM populations and their habitats was evaluated. We also aimed to define the environmental criteria required for the functional populations.
3. Analyses of toxicological substances
The role of the toxicological substances in the decline of FPM populations was evaluated by measuring the contents of heavy metals and other toxic substances from the river water, sediments and from the mussels themselves.
4. Genetic analyses
The genetic analyzes included the study of the genetic structure and the colonization history of the populations. In addition, the possible genetic host fish dependency of the mussels was examined.
5. Experiments with host fish and juvenile mussel cultivation
The methods for the artificial infection of the different host fish species and the laboratory cultivation of the mussels was developed during the project. In addition, the co-operations with fish farms was developed in order to infect the cultivated brown trouts and salmon with the FPM glochidia.
6. Searching for new populations
New FPM populations were searched with a new method, which was based on the inspection of glochidia infection from the electro fished host fish gills.
The common knowledge of the factors affecting to the state of the FPM populations was spread in the Finnish, Norwegian, Swedish and Sami language media.
The project area included Lapland and Ostrobothnia in Finland , Norrbotten in Sweden and the counties of Troms and Finnmark. in Norway.