Last updated 28 February 2024

Capelin (Mallotus villosus) are a small pelagic fish species that are an important food source for fish, seabirds and marine mammals and accordingly, they are considered to be a key species in the Barents Sea. The capelin stock in the Barents Sea is normally the largest in the world, but the size of the stock has varied greatly over the past 30 years.

Capelin. Photo: Jan de Lange / Institute of Marine Research

What is being monitored?

The capelin stock in the Barents Sea

The graph shows calculated sizes of immature stock and mature stock (spawning stock) of capelin in the Barents Sea. Together, this constitutes the total population.
(Cite these data: Institute of Marine Research (2024). Capelin stock in the Barents Sea. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL:

Details on these data

Last updated28 February 2024
Update intervalYearly
Next updateFebruary 2025
Commissioning organizationMinistry of Trade, Industry and Fishery
Executive organizationInstitute of Marine Research
Contact personsGro van der Meeren


The indicator is based on international advice from the Joint Russian-Norwegian Working Group on Arctic Fisheries.

The stock assessment and development are based on the measurements made during the annual Norwegian-Russian ecosystem cruise in the Barents Sea in September. This is an acoustic trawl that largely covers the entire capelin stock, and which provides an estimate of the amount of capelin and the composition of the stock.

The quantity estimate is made in the StoX software. In the stock assessment, the quantity estimate is used as an absolute estimate of the stock in the autumn, but since the fishing takes place the following winter and early spring, the stock is projected six months in time from the time the measurements take place. The projection is made using the Bifrost/ CapTool models, which use the quantity estimate from the cruise as input data, as well as calculations of maturation, growth and mortality (including grazing pressure of cod based on stock size, size composition and stomach samples). Assessment of uncertainty in cruise estimates and other input data are included in these model runs. In addition, FangstFisk is used to facilitate catch data.


Uncertainties related to the indicator depends on the accuracy and precision in the capelin stock assessment from the joint Norwegian- Russian cruise in September.

Other metadata

The Joint Russian-Norwegian Working Group on Arctic Fisheries (JRN-AFWG).

Reference level and action level

The reference level: None

Action level: The Joint Norwegian-Russian Fisheries Commission has decided a management rule that states that there should be less than 5 percent probability that the spawning stock should be less than 200,000 tons at the time of spawning. The Joint Russian-Norwegian Working Group on Arctic Fisheries advice on capelin management based on this rule.

Status and trend

The capelin stock was measured at 2.952 million tonnes in September 2023, of which the mature stock comprised 1.286 million tonnes. This stock level justifies opening the capelin fishery in 2024, for the third year in a row.

The Joint Norwegian-Russian fisheries commission, which determines the final capelin stock quota, recommended a quota of 196,000 tonnes of capelin for 2024.

The maturing part of the stock is estimated to amount to approximately 0.59 million tonnes at the time of spawning in spring 2024, given that the quota of 196,000 tonnes is taken out.

Causal factors

The capelin stock undergoes large fluctuations, even in the absence of human impact such as fishing. This may be explained by capelin being short-lived, they die after a single spawning and have variable recruitment. In addition, it is subject to strong predation by other fish, sea birds and sea mammals. This applies to both capelin fry and adult fish.

After a period of variable and partly low stock levels from 2014 to 2019, the stock has been stable at a relatively high level in the period 2020-2023. An important reason for the stability in recent years is good recruitment, especially from the 2019 year class, which is very strong, but also from the 2020 year class.


Fluctuations and collapses in the capelin stock have previously caused domino effects in the Barents Sea ecosystem.

Collapses of the capelin stock in the 1980s had major consequences for predators that feed on capelin, such as cod and harp seals. It was observed that cod had reduced growth, delayed maturation and individuals were leaner. Cod changed their diet and started to eat less nutritious foods such as crustaceans, and cannibalism became more widespread in that cod ate codlings. Food shortage caused Harp seals to embark on large feeding migrations both southwards and westwards, which among other things led to 77,000 harp seals drowning in nets along the Norwegian coast in 1987–1988. Collapses in the capelin stock in recent times have not had the same ecosystem consequences, possibly because predators have had access to better alternative food sources.

About the monitoring

The indicator describes the size of the mature part of the capelin stock and its changes over time. The Norwegian Institute of Marine Research and the Russian Institute of Marine Research update the time series every autumn, based on a joint cruise with several vessels. This has been going on since 1973.

The Joint Russian-Norwegian Working Group on Arctic Fisheries uses these data series to provide its stock assessment.

The size of the mature part of the capelin stock is used in a well-established management system under the operation of the Joint Norwegian-Russian Fisheries Commission, following the advice of The Joint Russian-Norwegian Working Group on Arctic Fisheries.

It should be considered whether the total population of capelin should be used as an indicator for the future. The total population will better show the role of capelin as a key species in the ecosystem, both as grazing on zooplankton and as prey for fish and mammals.

Places and areas

Relations to other monitoring

Monitoring programme

International environmental agreements

Voluntary international cooperation

  • None

Related monitoring

  • None

Further reading



  1. Bakketeig, I.E., Gjøsæter, H., Hauge, M., Sunnset, B.H., & Toft, K.Ø. (red.) (2015). Havforskningsrapporten 2015. Fisken og havet, særnr. 1–2015.
  2. Gjøsæter, H., Dommasnes, A., & Røttingen, B. (1998). The Barents Sea capelin stock 1972–1997. A synthesis of results from acoustic surveys. Sarsia83(6), 497-510.
  3. Toresen, R., Gjøsæter, H., & de Barros, P. (1998). The acoustic method as used in the abundance estimation of capelin (Mallotus villosus Müller) and herring (Clupea harengus Linné) in the Barents Sea. Fisheries Research34(1), 27-37.