Age laboratories at the Department of Aquatic Resources

Last changed: 05 March 2021
Woman sitting at microscope. Photo.

SLU Aqua's three age laboratories specialize in age and growth analyzes of fish from Sweden's seas, coasts, lakes and watercourses. Every year, our experts analyze more than 50,000 fish from about 20 different species. The results from our biological analyzes and age determinations are used to assess the status of fish stocks, and constitute important decision bases for both national and international fish management.

Age analysis of fish can provide detailed information about fish stocks and how fish react with, for example, changes in the environment or fishing pressure.

Fish age is estimated with the help of the otoliths (ear stones), gill caps, scales and other skeletal parts or hard tissues, which get annual rings in the same way as trees. In addition to the age of the fish, by studying these tissues you can also measure growth of the fish at a given age. Read more about age analysis of fish >>

Quality-assured data for fish management

We perform age analyzes for research purposes and as part of international and national fish and environmental monitoring on behalf of the Swedish Maritime Administration, county administrative boards, municipalities, fishing associations, fisheries conservation areas, etc.

We perform age determinations and analyzes on assignment. Contact our age laboratories for information and pricing! (Contact information can be found at the bottom of the page)

Information on the age and growth of fish is required, among other things, to gauge the status of a fish stock, make stock analyzes and assess what fishing pressure a stock can handle. Our age analyzes are used, among other things, for stock estimates and advice given by the International Council for the Exploration of the Sea, ICES, which serve as a basis for decisions on the EU's common fisheries policy.

Our age laboratories work continuously with quality assurance and method development and our experts regularly participate in international workshops and exchange programs. Read more about our quality assurance and development of age analysis on fish>>

Operculum with annuals. Photo.
Gill caps, otoliths (ear stones), scales and other hard tissues get annual rings in the same way as trees. The gill cover in the picture shows that the perch was four years old when it was caught.
People sorting fish at a conveyor belt
During the Baltic International Trawl Survey (BITS) and other research trawls, samples from commercially important fish species are collected for age analysis. Photo: Peter Wickström
Eel on a ruler. Photo.
Most fish analyzed at SLU Aqua's age laboratories are collected during standardized test fishing and by commercial fishing. The eel in the picture - "Urhultsålen" - was however sent in for age analysis by a family who found it dead in their well. The eel turned out to be 88 years old. Photo: Martina Blass
Man sitting in front of a computer screen and watching a fish picture. Photo.
At SLU Aqua's age laboratories, continuous development work is underway. On the computer screen, the head of a perch about a centimeter large can be seen, on which the hearing stones our experts have analyzed the day rings (ie not the annual rings). Photo. Sofia Bureborn

Age analyzes at the Institute of Marine Research in Lysekil

At the Institute of Marine Research, age analyzes are mainly performed for stock assessments within the EU Data Collection Directive (EU-MAP / DCF).

Among the species analyzed are herring, sprat, cod, saithe, plaice and sole.

The majority of the fish that are age-analyzed are collected in internationally coordinated fish surveys with research vessels and from commercial fishing vessels.  

Age analyzes at the Institute of Coastal Research in Öregrund

At the Institute of Coastal Research, age analyzes are performed in three main areas:
• Regional and national environmental monitoring at the coast
• Recipient control at nuclear power plants
• EU Data Collection Directive (EU-MAP / DCF)

Among the species analyzed are perch, herring, eel, whitefish, flounder, pikeperch and black-mouthed butterfish.

Fish that are age-analyzed are collected in standardized test fishing conducted within the various programs for regional and national environmental monitoring and within the recipient control programs. Some also come from internationally coordinated fish surveys with research vessels and commercial fishing vessels.

Age analyzes at the Institute of Freshwater Research at Drottningholm / Stockholm

At the Institute of Freshwater Research, age analyzes are mainly performed on fish in three main areas:

• National environmental monitoring of small and medium-sized lakes
• Monitoring of fish stocks in the large lakes Vänern, Vättern, Mälaren and Hjälmaren
• EU Data Collection Directive (EU-MAP / DCF)

Among the species analyzed are perch, roach, pikeperch, smelt, salmon and eel.

Fish that are age-analyzed are mainly collected from standardized test fishing in lakes, hydroacoustic surveys and through collections made  in collaboration with professional fishermen.


Contact

Carina Jernberg, Head of Unit
Department of Aquatic Resources, Institute of Marine Research, SLU
carina.jernberg@slu.se, +46 10 478 4025, +46 761-26 80 16

Martina Blass, Environmental Monitoring and Assessment Analyst
Department of Aquatic Resources, Institute of coastal research, SLU
martina.blass@slu.se, +46 10 478 41 18

Magnus Kokkin, Environmental Monitoring and Assessment Analyst
Department of Aquatic Resources, Institute of Freshwater Research, SLU
magnus.kokkin@slu.se, +46 10 478 42 35

Page editor: sofia.bureborn@slu.se