Genetic research on commercially exploited fish species in Nordic countries

During the last decades the human impact on wild populations of fish has increased drastically worldwide as a result of extensive aquaculture, exploitation for consumption and human-induced environmental change. Such activities likely affect the genetic diversity and structure of targeted species, and maintenance of genetic diversity has in turn been accepted as an internationally and common long-term goal in management of wild populations. Knowledge of neutral and adaptive genetic diversity is crucial since it provides information on the extent of local adaptations, the genetic population structure and the evolutionary potential of a species and/or population. The genetic architecture of a species also provides the basis for understanding and predicting responses to changes at higher system levels, and the genetic diversity might function as an indicator of key ecosystem functions such as the total viability of the ecosystem. Information on the genetic structure of commercially important fish species is therefore crucial to prevent ecological damage and to ensure sustainable and effective management of exploited stocks and systems. The modern molecular methods developed during recent years offer unique opportunities for studying genetic processes and patterns in wild populations.s Sustainable management is therefore greatly facilitated, and in some instances, heavily dependent on the implementation of modern genetic techniques. Genetic research on commercially exploited fish species in the Nordic countries has a long tradition and is currently undertaken at several research institutes in all countries. The implementation of this research in management has, however, hitherto been limited. This report reviews the current knowledge on genetics in Nordic fish species, identifies the existing gaps in the knowledge, and aim to provide a foundation for advices of future ventures in this area of research. The emphasis is directed to five different subjects where genetic information is crucial for effective management: Identification of population structure, Stocking, Escapes from Aquaculture, Fisheries-induced evolution, and Effects of environmental change. For each subject we discuss how the genetic information can be used in management, give a short summary of the current knowledge on the subject, and highlight the information needed in the future. We also provide a brief overview of the genetic research conducted on fish (both marine and freshwater) and other important aquatic taxa in the Nordic countries, highlight where the existing competence in population genetic methods in the Nordic countries is located, and identify established cooperation and networks between affiliations and countries.