Genetic research on commercially exploited fish species Background
There are many ways in which human activities (fishing, rearing, stocking and habitat destruction) can change the original genetic composition of exploited fish species, thus posing the risk of harmful genetic changes. Genetic research is needed in order to assess the scale of realized genetic changes and to evaluate the risks they pose for the viability of fish stocks. Genetic theory also offers a means of avoiding such harmful effects. Risks affecting genetic diversity are usually caused by a decrease in population size, unnatural selection either in hatcheries or as result of selective fishery, and unnatural gene flow resulting from the mixing and transporting of fish stocks.
Objectives
Genetic research includes projects aiming to produce information on maintaining genetic diversity both in quantitative traits and at DNA-level, and also to use genetic information in management decision-making and for catch composition analysis.
The long-term objective is to meet the goal of sustainable use, a state in which genetic diversity is not decreased because of human activities (especially hatchery rearing, stocking and fishing). The goal of the genetic research is to increase understanding of the natural evolutionary differences between fish stocks and the implications of these differences for exploitation, management and conservation practices concerning commercially valuable fish. Another goal is to use DNA-level information as genetic tags in identification at the stock and individual levels: for example, in catch composition analysis to estimate the proportions of different stocks in mixed-stock fisheries.
Current tasks
1) - To describe and identify the potential genetic groups within effectively managed fish species including Atlantic salmon (Salmo salar), brown trout (Salmo trutta), whitefish (Coregonus lavaretus) and pikeperch (zander) (Sander lucioperca). A standard set of DNA-microsatellite loci has been developed for national purposes.
2) - To develop genetic methods for stock and individual identification, and applications of these methods in catch composition analysis of Atlantic salmon catches in mixed stock fisheries in the Baltic Sea.
3) – To monitor annually the Atlantic salmon catch composition in three sea areas of the Baltic Sea (Baltic Main Basin, Åland Sea and Bothnian Bay).
4) - To study inheritance and changes in quantitative life history traits (i.e. migration behaviour, growth rate, age at maturity), and their relationship to survival.
Scientist in charge of project
Marja-Liisa Koljonen
Finnish Game and Fisheries Research Institute
Viikinkaari 4, P.O. Box 2
FIN-00791 Helsinki, Finland
+358 205 751 315
e-mail: firstname.lastname@rktl.fi
Other research staff: Irma Kallio-Nyberg
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