Applications of Genetics

Last changed: 27 July 2016

SLU uses the results from genetic studies in fisheries management and research.

Genetic structure

Most species are divided into genetically distinct populations. Sustainable management must be based on biological knowledge about the population genetic structure within species. From a short term perspective, over-exploitation of populations could lead to reduced abundance and natural production, which can take a long time for nature to "heal". Loss of biodiversity in the form of local populations and genetic variation could also in the long run reduce a species' capacity for survival and continued development.

With the help of DNA markers, it is possible to study the genetic population structure of various fish and shellfish species. Genetic techniques are also used as a complement to traditional tagging programmes in the study of fish migration, for investigations of taxonomic status of species and populations, and to identify the composition of individuals and populations in catches of fisheries.

Mixed-stock fisheries

In many cases, catches include individuals from multiple populations. Fishing for salmon in the southern Baltic Sea, where individuals from populations throughout the Baltic region occur together during the feeding migration, constitutes a clear example. By genetically analyzing samples collected at different times and in different areas it is possible to estimate the composition of populations (wild or reared) in the catch. The results can be used as a basis for reducing fishing on weak populations.

Fisheries control

Using genetic markers it is possible to determine the species and sometimes the population/geographic origin of fish and shellfish. Sampling of DNA can either be directly associated with landings or later with wholesalers and retailers (such as frozen fillets).

Fish releases

Movement and release of fish is a common management measure. Using genetic studies, it is possible to evaluate the impact of such activities. For example, it is possible to estimate the share of the catch that consists of released individuals, i.e. it is possible to evaluate the economic yield of the release activity. To measure the degree of genetic influence on natural populations (through hybridization) is another important use.

Kinship and behaviour

The fact that individuals are genetically different makes it possible to use DNA analysis to distinguish between individuals (so-called genetic fingerprint). Similarly, it is also possible to determine parentage, estimate relatedness, and measure reproductive success (number of offspring). Genetic markers are thus a valuable tool in studies and experiments aimed at studying behaviour and genetic adaptations.


When fish and shellfish are reared in aquaculture for consumption, genetic markers can be useful for keeping track of individuals and how they are related in the context of breeding programs. Another use is to improve breeding procedures by identifying individuals with particularly desirable gene combinations for certain characteristics (high growth rate, disease resistance, etc.).

Protection of valuable wild populations

Genetic markers can be used to identify valuable populations of endangered or commercially important species. For example, to identify particularly unique populations that for some reason have low degree of genetic variation, or showing a threatening low population size.

With the help of regular collection of molecular genetic data from selected populations, called genetic monitoring, it is possible also to detect changes that may indicate reduced population sizes, loss of genetic variation and/or increased presence of foreign genes (for example as a result of interactions with stocked fish).


Ann-Britt Florin, Head of Division
Department of Aquatic Resources, Institute of Coastal Research, SLU, +46 10 478 41 22