Age laboratories at the Department of Aquatic Resources

Last changed: 28 February 2025
Woman sitting at microscope. Photo.

The Department of Aquatic Resources specialize in age and growth analyses of fish from Sweden's seas, coasts, lakes and waterways, and we have three laboratories that conduct ageing studies. Every year, our experts analyze more than 50,000 fish from about 20 different species. The results from our biological analyses and age determinations are used to assess the status of fish stocks, and constitute important decision-making information for both national and international fish management.

This is what we do

We perform ageing studies for research purposes and as part of international and national fish and environmental monitoring on behalf of the Swedish Agency for Marine and Water Management, county administrative boards, municipalities, and fishing associations.

We also perform age determinations and analyses on behalf of clients. Contact our age laboratories for information and pricing. Contact details can be found at the bottom of the page.

Our age laboratories

Age analysis 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, European plaice and Witch flounder.

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

Age analysis at the Institute of Coastal Research in Öregrund

At the Institute of Coastal Research, we perform age analyses in three main areas:

  1. Regional and national coastal environmental monitoring.
  2. Environmental monitoring at nuclear power plants.
  3. The EU Data Collection Directive (EU-MAP/DCF).

Among the species we analyse are perch, herring, eel, vendace, viviparous eelpout, whitefish, European flounder, pike-perch and the round goby.

The fish we age analyse are collected during standardised fish surveys, which we carry out within the various programmes for regional and national environmental monitoring and within the monitoring programmes at the nuclear power plants. A certain proportion of the fish also comes from internationally coordinated fish surveys with research vessels and from commercial fishing.

Age analysis at the Institute of Freshwater Research at Drottningholm

At the Institute of Freshwater Research, we primarily perform age analyses on fish in three main areas:

  1. National environmental monitoring of small and medium-sized lakes.

  2. Monitoring of fish stocks in Sweden's largest lakes: Lake Vänern, Lake Vättern, Lake Mälaren and Lake Hjälmaren.

  3. The EU's data collection directive (EU-MAP/DCF).

Some of the species we analyze are perch, roach, pike-perch, smelt, salmon and eel.

The fish that we analyze mainly come from standardized sampling in lakes, hydroacoustic surveys and via collections in collaboration with professional fishermen.

Why do we need to know the age of fish?

Information on the age and growth of fish is required to determine the status of a fish stock, conduct stock analyses and assess how high fishing pressure a stock can withstand. Our age analyses are used for the stock estimates and advice given by the International Council for the Exploration of the Sea, ICES, and which are used as a basis for decision-making for the EU's common fisheries policy.

How age analysis works

We estimate the age of a fish using the fish's otoliths, operculum, scales and other bones, which have annual rings in the same way as trees. Here you can read more about age analysis of fish.

Method manual for age analysis of fish

Our experts in age determination have compiled a method manual for age determination of fish. The method manual describes in detail the different stages in age determination for different species. Here you can read more and download the method manual (in Swedish).


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