CAPELIN

Mallotus villosus


Assessment report
Published by

Marine and Freshwater Research Institute, Iceland

Published

25 February 2026

Executive summary

  • The size of the capelin stock and the catches have fluctuated between years and are reflecting the size of the incoming cohort at any given time. Initial and intermediatd TAC are based on autumn survey but due to a number of sources of uncertainty final advice is based on both autumn and winter surveys.

  • The mature part of the capelin stock was estimated to be 418 thousand tonnes in the 2025 autumn survey and 710 thousand tonnes in the 2026 winter survey. Considering the measurement combination of autumn (weighted 1/3) and winter (weighted 2/3) surveys, the estimated predation on the capelin stock, and the coastal states’ harvest control rule, the capelin catch for the 2025/2026 fishing year is recommended not to exceed 197 474 tonnes.

  • The total biomass estimate in the winter survey of 2026 was 744 thousand tonnes. The distribution of mature components in the stock was about 55% (382 thousand tonnes) east of Iceland, following the traditional spawning migration clockwise to the area south and west of the country, and about 45% northwest of Iceland (328 thousand tonnes).

General information

The capelin is a small pelagic schooling fish. It is a cold-water species that inhabits arctic and subarctic waters in the North Atlantic and North Pacific. Capelin in the Iceland-East Greenland-Jan Mayen area (IEGJM) is considered to be a single stock, and is denoted hereafter as the IEGJM capelin stock.

Fisheries of capelin began in Iceland in the mid-1960s. Besides being commercially important, capelin is a key species in the marine ecosystem off Iceland. It feeds on small zooplankton, especially copepods but also amphipods and krill. It is also itself an important food for cod, saithe, haddock, halibut and other commercial fish, as well as for whales and seabirds. Thus, capelin is an important link in the transfer of energy and nutrients to the upper levels of the food web. Preferred temperature for capelin is usually 1–3°C during its feeding migration and it is then often at the southern extent of cold Arctic water. When adult capelin migrate from the feeding areas far north of Iceland, east and southeast of Greenland, it is mainly considered to approach the shelf break north of Iceland and then migrate clockwise around the island. Part of the main migration continues all the way towards the coast west of Iceland. Spawning takes place in shallow water in March–April in relatively warm seas along the south and southwest coast of the country. Spawning has also been observed in coastal areas north of Iceland but the extent of that spawning has been considered small compared to the number that spawns in the south. The majority of capelin dies after spawning, usually at the age of 3 years, although mainly females may survive spawning (Christiansen et al., 2008). The migrations of capelin contribute to a huge transfer of energy into the ecosystem of the Icelandic continental shelf. Larvae and juveniles drift clockwise along the continental shelf north and east of Iceland and in variable quantities towards the Denmark Strait and to the shelf of East Greenland. Nursery grounds of capelin are in the waters north of Iceland and increasingly on the continental shelf of East Greenland since the early 2000s (Bardarson et al., 2021; Singh et al., 2023).

Fisheries

Fisheries on the IEGJM capelin stock in the 2024/2025 fishing season was historically low. A total of 9 439 t catches were fished during the winter of 2025 (Figure 1). Total historical catch of the stock is shown in Figure 1 by season and distribution of the catches of the Icelandic fishing fleet by year can be seen in Figure 2.

Figure 1: Capelin. Total catch (in thousand tonnes) since 1963/64 by season.
Figure 2: Capelin. Distribution of catches by the Icelandic fishing fleet based on logbooks.

The capelin caught during the 2024/2025 fishing season was primarily taken by purse seine. Historically, most of the catches have been taken by purse seine but a variable amount has been taken with pelagic trawl through the fishing seasons, related to the size of the TAC and when it is issued. Discards have been considered negligible.

Stock assessment

Capelin acoustic assessment surveys

The IEGJM capelin stock has been assessed by acoustics annually since 1978. The surveys have been conducted in autumn (September–December) and in winter (January–February). An overview of the assessment method is given in the International Council for the Exploration of the Seas Northwestern Working Group report stock annex ICES NWWG .

Autumn survey 2025

Autumn surveys are conducted with the aim of assessing both the immature and the maturing part of the stock (Bardarson et al., 2024). Since 2010, the autumn surveys have started in September (and partly in late August), a month earlier than in the preceding years because of difficulties in covering the stock due to drift ice and bad weathers during later months at the more north-westerly feeding grounds of the stock since early 2000s (Vilhjálmsson, 2007).

The survey was conducted on behalf of the MFRI by the r/v Arni Fridriksson and r/v Tarajoq on behalf of the GINR (Greenland Institute of Natural Resources) (Figure 3). The survey area was on and along the shelf edge off East Greenland from about 64°30´N towards about 72°15´N, also covering the Denmark Strait and the slope off northwest Iceland. The Iceland Sea and Jan Mayen area were only briefly scouted due to time constraints and for same reason hydrographic measurements and zooplankton sampling were limited due to bad weather conditions. The initial planned survey tracks had to be changed due to stormy weather.

In general, drift ice only limited the coverage of the survey vessels in a few regions although icebergs and a lack of information on bottom topography occasionally affected routes and limited the extent of transects towards the Greenlandic coast (Figure 3).

Maturing capelin was mainly observed outside the Icelandic continental slope North and Northwest of Iceland (between 68–70°N and 20–22°W, see Figure 4). In the western Denmark Strait maturing capelin was mixed with immature capelin, while mainly maturing capelin was found further north east outside of Scoresby Sound. Similar to last year, the distribution of mature capelin reached only a relatively short distance east of Denmark Strait. Further, no capelin was found near the western part of the Jan Mayen ridge or further north of 71°N. Juveniles (0-group) of various species, including capelin (although not quantified) were observed along the continental shelf north and northwest of Iceland and along the southwestern coverage of the Greenlandic shelf. Immature capelin was found along the Greenlandic shelf, dominating in southwestern part of the survey area and close to the coast along Denmark Strait (Figure 4).

Figure 3: Capelin. The relative density of acoustic backscatter as NASC during 23 August–22 September 2025. Survey tracks by r/v Arni Fridriksson, and r/v Tarajoq are shown in different colors.
Figure 4: Capelin. Transects of the participating vessels and proportion mature within samples and regional allocation in assessment during the autumn survey in 23 August–22 September 2025.

The total biomass of capelin estimate was 1 209 thous. tonnes of which the size of the mature part of the stock was 417.5 thousand tonnes. The immature part was 791 thousand tonnes. The index of the abundance of juvenile capelin was 118.9 billion, the 5th largest in the time series and indicating that the year class 2024 (spawned in spring 2024) is large. Table 1 gives information on the age-disaggregated numbers and biomass of the capelin total stock.

Table 1: Capelin. Estimated total stock size in numbers (N) and biomass (tonnes) by age (years) and length (cm) from the autumn acoustic survey (23 August to 22 September 2025, see Figure 3).
Category Length age1 age2 age3 age4 age5 Total Number Total Biomass (tonnes)
Immature 8.5 1165 0 0 0 0 1165 3337
Immature 9 3680 0 0 0 0 3680 11877
Immature 9.5 2939 0 0 0 0 2939 10583
Immature 10 5293 0 0 0 0 5293 21200
Immature 10.5 10316 0 0 0 0 10316 44837
Immature 11 8386 0 0 0 0 8386 40235
Immature 11.5 12052 0 0 0 0 12052 63357
Immature 12 12267 0 0 0 0 12267 71473
Immature 12.5 11810 79 0 0 0 11890 76413
Immature 13 10220 79 0 0 0 10300 71446
Immature 13.5 10512 79 0 0 0 10591 80606
Immature 14 11482 316 0 0 0 11798 97963
Immature 14.5 5111 238 79 0 0 5429 49484
Immature 15 3791 477 79 0 0 4347 43612
Immature 15.5 2648 711 0 0 0 3359 36974
Immature 16 676 412 0 0 0 1087 12572
Immature 16.5 446 1027 0 0 0 1474 17682
Immature 17 446 250 79 0 0 776 10291
Immature 17.5 96 397 79 0 0 573 8589
Immature 18 16 430 25 0 0 471 6807
Immature 18.5 0 128 159 0 0 287 5059
Immature 19 0 159 0 0 0 159 2941
Immature 19.5 0 96 0 0 0 96 1791
Immature 20 0 48 79 0 0 128 2701
Mature 8.5 25 0 0 0 0 25 141
Mature 9 78 0 0 0 0 78 508
Mature 9.5 25 0 0 0 0 25 185
Mature 10 356 0 0 0 0 356 2741
Mature 10.5 329 0 0 0 0 329 2899
Mature 11 530 25 0 0 0 555 5608
Mature 11.5 491 126 0 0 0 617 6727
Mature 12 343 178 0 0 0 521 5919
Mature 12.5 511 434 79 0 0 1024 12946
Mature 13 187 665 0 79 0 931 13104
Mature 13.5 231 1079 0 0 0 1310 19810
Mature 14 157 1946 105 0 0 2207 37769
Mature 14.5 25 1651 82 0 0 1758 32437
Mature 15 0 2304 89 0 0 2393 47764
Mature 15.5 0 1404 50 0 0 1455 32198
Mature 16 0 2058 119 0 0 2177 52370
Mature 16.5 0 1168 176 0 0 1344 34923
Mature 17 0 1218 278 0 0 1496 42556
Mature 17.5 0 718 213 16 0 948 28345
Mature 18 0 379 113 41 0 533 17403
Mature 18.5 0 145 147 0 16 308 10889
Mature 19 0 25 64 0 0 89 3342
Mature 19.5 0 0 122 0 0 122 4867
Mature 20 0 0 25 0 0 25 1257
Immature Total 113351 4929 582 0 0 118861 791828
Mature Total 3288 15522 1663 137 16 20626 416708

The historical trend of mean weight of immature 1 to 3 year old capelin during the autumn survey is shown in Figure 5, as well as the trend of the mean weight of the mature capelin 1 to 4 year old capelin in Figure 6. The mean weight of 1 and 2 year old immature capelin has increased over time for all age classes, especially since 2000. Older age groups consistently show higher mean weights, with 3 year old immature capelin (Figure 5) and 4 year old capelin (Figure 6) exhibiting the most variability in mean weight.

Figure 5: Capelin. Mean weight of 1 to 3 year old immature capelin in autumn surveys since 1978. Colors are indicative of the different age classes and the dash lines represent the average weight for each age group from 1978 to 2025 (highlighted in grey). Lines indicate a loess smoother (smoothing span 50% of the data). Lowest and highest values per class are highlighted with gray and black circles.
Figure 6: Capelin. Mean weight of 1 to 4 year old mature capelin in autumn surveys since 1978.Colors are indicative of the different age classes and the lines represent the average weight for each age group from 1978 to 2025 (highlighted in grey). Lines indicate a loess smoother (smoothing span 50% of the data). Lowest and highest values per class are highlighted with gray and black circles.

Surveys in winter 2025/2026

The main objective of the winter surveys is to assess the mature part of the stock using acoustic stock assessment accompanied with pelagic trawl sampling. These surveys are a coordinated by MFRI and collaboration between research vessels and commercial vessels normally rented by MFRI Scientists from MFRI are normally on board each vessel during the main surveys in January, oversaw and interpreted the acoustic measurements. All the participating vessels, have calibrated echo sounders, generally performed shortly before the surveys.

January 2026: exploratory survey

The first winter survey in January was conducted from 5 to 12 on the r/v Árni Friðriksson (Figure 7), and was planned as an exploratory survey. The survey tracks were design to cover on strata centered along the east and northeast of Iceland with the objective to evaluate the progression of the capelin migration and assist to the planning of the large expedition. During the survey, the majority of the mature capelin (150 thousand tonnes) were found in the north and northeast of Iceland (Figure 7), indicating that the capelin was still in the north and had not migrated southwards. The survey had a relative high coefficient of variation (CV=0.25) for the mature stock estimate. Table 2 gives information of the age-disaggregated numbers and biomass of the capelin stock components.

Figure 7: Capelin. The relative density of acoustic backscatter as NASC and proportion mature in capelin samples from 5 to 12 of January 2026. Survey tracks are shown in different colors. Proportions below 0.5 are shown as black to green points, while proportions above 0.5 to 1 in ligth green to yellow, respectively.
Table 2: Capelin. Estimated stock size of IEGJM capelin immature and mature stock in numbers (N) and biomass (B, tonnes) by age (years) and length (cm) from the January acoustic survey (5 to 12 January 2026, see Figure 7).
Category Length age2 age3 age4 age5 Total Number Total Biomass (tonnes)
Immature 8.5 0 9 0 0 9 52
Immature 9.5 19 0 0 0 19 136
Immature 10 38 0 0 0 38 317
Immature 10.5 19 0 0 0 19 159
Immature 11 28 0 0 0 28 244
Immature 11.5 47 0 0 0 47 462
Immature 12 38 9 0 0 47 524
Immature 12.5 57 9 0 0 66 722
Immature 13 9 0 0 0 9 111
Immature 13.5 9 38 0 0 47 630
Immature 14 38 28 0 0 66 922
Immature 14.5 9 47 0 0 57 835
Immature 15 0 47 0 0 47 817
Immature 15.5 0 19 0 0 19 322
Immature 16 0 38 9 0 47 848
Immature 16.5 0 38 0 0 38 740
Immature 17 0 38 0 0 38 811
Immature 17.5 0 9 0 0 9 219
Immature 18.5 0 9 0 0 9 254
Immature 19 0 9 0 0 9 294
Immature 20 0 9 0 0 9 287
Mature 8.5 9 9 0 0 19 106
Mature 12 57 19 0 0 76 834
Mature 12.5 57 104 0 0 161 1910
Mature 13 38 104 0 0 142 1847
Mature 13.5 28 351 0 0 379 5413
Mature 14 28 398 0 0 427 6841
Mature 14.5 9 417 0 0 427 7178
Mature 15 0 967 9 0 976 18468
Mature 15.5 9 758 9 0 777 15773
Mature 16 0 777 38 0 815 17916
Mature 16.5 9 645 28 0 682 16152
Mature 17 9 720 66 9 806 20626
Mature 17.5 0 474 57 0 531 15153
Mature 18 0 332 47 0 379 11607
Mature 18.5 0 171 28 9 209 6738
Mature 19 0 38 9 0 47 1717
Mature 19.5 0 19 19 0 38 1386
Mature 20 0 0 9 0 9 338
Immature Total 313 360 9 0 682 9704
Mature Total 256 6303 322 19 6900 150000

January 2026: first assessment survey

The second winter survey was conducted from 19 to 26 January 2026 on the research vessels Árni Friðriksson and Þórunn Þórðardóttir, and the fishing vessels Barði, Heimaey, and Polar Ammassak (Figure 8). The survey tracks were designed to cover four strata, centered on the east, northeast, north, and northwest of Iceland. During the survey, the majority of mature capelin were found in the north and east of Iceland (Figure 8). The capelin found furthest northwest of Iceland were immature fish. The mature part of the stock was estimated to be 710 800 t (CV=0.24), where about 55% (382 thous. tonnes) was east of Iceland, following the traditional spawning migration clockwise to the area south and west of the country, and about 45% northwest of Iceland (328 thous. tonnes). It was not clear which direction the mature stock component north of Iceland would migrate, and the third survey was conducted to explore that further (starting 11 of february). Table 3 gives information of the age and length disaggregated numbers and biomass of the capelin stock.

Figure 8: Capelin. The relative density of acoustic backscatter as NASC and proportion mature in capelin samples from 19 to 26 of January 2026. Survey tracks are shown in different colors. Proportions below 0.5 are shown as black to green points, while proportions above 0.5 to 1 in ligth green to yellow, respectively.

The capelin distribution in January 2026 had a similar distribution in the winter of 2023 (the parents’ generation). In the 2023 advice on fishing opportunities of the parents’ generation, MFRI proposed that in addition to the total catch limit, precaution should be taken to avoid heavy fishing focused solely on the stock component that followed the traditional spawning route east of the country, where fishing tends to be more efficient. MFRI proposed that two-thirds of the catch limit should focus on capelin offshore from Húnaflói (after the February monitoring survey) to prevent local depletion of diversity in mature stock components. Subsequently, this advice was then abandoned when it was considered clear that the capelin to the northwest were returning west for spawning.

Table 3: Capelin. Estimated stock size of IEGJM capelin immature and mature stock in numbers (N) and biomass (B, tonnes) by age (years) and length (cm) from the January acoustic survey (19 to 26 January 2026, see Figure 8).
Category Length age2 age3 age4 age5 Total Number Total Biomass (tonnes)
Immature 8.5 30 0 0 0 30 104
Immature 9 30 0 0 0 30 104
Immature 9.5 50 0 0 0 50 208
Immature 10 139 0 0 0 139 695
Immature 10.5 253 0 0 0 253 1368
Immature 11 265 16 0 0 281 1704
Immature 11.5 321 16 0 0 337 2229
Immature 12 392 0 0 0 392 2903
Immature 12.5 291 0 0 0 291 2314
Immature 13 378 17 0 0 395 3451
Immature 13.5 159 22 0 0 181 1784
Immature 14 171 70 0 0 241 2620
Immature 14.5 77 61 0 0 139 1754
Immature 15 70 134 0 0 204 2763
Immature 15.5 37 97 17 0 151 2301
Immature 16 1 96 0 0 97 1552
Immature 16.5 17 204 16 0 237 3933
Immature 17 0 38 0 0 38 716
Immature 17.5 0 1 0 0 1 21
Immature 18.5 0 28 0 0 28 580
Immature 20 0 0 17 0 17 534
Mature 8.5 0 28 0 0 28 177
Mature 9 28 0 0 0 28 267
Mature 10 116 16 0 0 131 1216
Mature 10.5 98 18 0 0 117 1146
Mature 11 173 220 0 0 393 4282
Mature 11.5 129 238 0 0 367 4394
Mature 12 76 318 0 0 394 5056
Mature 12.5 236 1101 18 0 1356 19296
Mature 13 108 964 0 0 1073 16443
Mature 13.5 37 1578 17 0 1632 26826
Mature 14 69 3408 70 0 3546 63686
Mature 14.5 26 2130 53 0 2209 43853
Mature 15 34 2674 49 0 2758 57472
Mature 15.5 55 4229 162 17 4463 102783
Mature 16 0 2617 311 0 2929 72043
Mature 16.5 0 2713 230 0 2944 76341
Mature 17 0 2831 600 17 3448 98822
Mature 17.5 0 1171 234 0 1405 42704
Mature 18 0 795 191 0 986 31916
Mature 18.5 0 373 280 17 671 22717
Mature 19 0 153 28 0 181 6623
Mature 19.5 0 0 235 0 235 8805
Mature 20 0 43 16 0 59 2478
Immature Total 2680 801 50 0 3531 33638
Mature Total 1186 27618 2495 52 31350 709344

Predation model results

Following the completion of surveys, estimations of stock parameters and their uncertainties from 100 thousand bootstrap replicates of the mature part of the stock were used as starting values for predation model runs. Results from the predation model runs are given in Table 4 and shown in Figure 10 and Figure 11.

Table 4: Capelin. Quantiles and mean of SSB at time of spawning (15. March) and total predator consumption in tonnes based on the predation model
mean 5% 25% 50% 75% 95%
SSB 266410 114360 189670 255490 330800 457280
Predation 148230 101360 125450 145240 167880 205070

The predation model (Ices 2023, ICES 2024) is designed to cover predation of cod, haddock and saithe on the main spawning migration of capelin during 15 January and 15 March. A schematic description of the model is shown in Figure 9.

Figure 9: Capelin. Top pannel: the yellow arrows show the migration route with the 3 regions used in the simulations of predation on the capelin migration starting in the east. Bottom pannel: shows a schematic proportional distribution of migrations and catches in the predation model as discretized over 2-week intervals. Catches are shown as fractions below horizontal arrows and clockwise migrations are given as percentages over vertical arrows.
Figure 10: Capelin. Summary of results from the 2025 autumn and winter 2026 acoustic survey and predation model. Biomass survey estimates of mature capelin (top-left), the projected spawning stock biomass left for spawning based on the predation model (top-right), predicted predation 15 January – 15 March (bottom-left) and the applied predation mortality (bottom-right).
Figure 11: Capelin. Predicted development of the SSB with 197 474 catch based on the predation model. Blue line indicates Blim = 114 000 tonnes (Ices 2023, ICES 2024).

Management

Agreed management plan and HCR

The Coastal States (Iceland, Greenland, and Norway) agreed (Anon. 2015; Anon. 2023) to use the following harvest control rule as the basis for management, following the rule developed and revised by ICES (ICES, 2015; ICES, 2023).

The objective of the Harvest Control Rule is to set a final TAC which ensures, with a 95% probability, that a minimum of 114,000t (Blim) remains for spawning. This is achieved by a series of acoustic surveys from September - February and the TAC is determined in three stages; an initial TAC, an intermediate TAC and a final TAC.

  1. The initial TAC for the next fishing season is set based on estimates of the immature part of the stock following an acoustic survey in autumn (September - October).

    Two fixed points are defined:

    1. Utrigger = 50 billion immature capelin.

    2. TACMax = 400,000 tonnes for U > 127 billion immature capelin.

    The method for setting the initial/preliminary TAC is:

    • TAC = 0 if Uimm < 50 billion.

    • TAC = 5.2 x (Uimm - Utrigger) thous. tonnes for Uimm in the range 50–127 billion.

    • TAC = 400,000 tonnes if Uimm > 127 billion.

  2. The intermediate TAC for the current fishing season is set following the acoustic survey in autumn. Estimates on capelin spawning stock biomass (SSB) with uncertainty estimate are combined with data on predicted predator stocks size and distribution. The estimates are fed into a predation model run with varying catches until spawning in March. The intermediate TAC is set at 2/3 of the catch giving p(SSB < Blim = 114,000 tonnes) < 0.05.

  3. The final TAC is set following an acoustic survey in winter (January-February). Estimates on capelin spawning stock biomass with uncertainty estimate are combined with data on predicted predator stocks size and distribution. Final TAC is set based on all valid acoustic surveys on the mature part of the stock from autumn to winter. The estimates are fed into a predation model run with varying catches until spawning in March. The final TAC is set at the catch giving p(SSB < Blim = 114,000 tonnes) < 0.05. After ICES (2023), it was decided that the autumn survey is weighted a maximum of 1/3.

Initial advice 2025/2026

In June 2025, the initial advice for 2025/2026 was above the zero catch because the index for immature fish from the autumn acoustic survey 2024 was 58.9 billion, and was above the Utrigger value (50 billion). Based on this rule (see Section 6.1), the initial TAC was 46 384 t for the fishing season starting 15 October 2025 to 15 April 2026 (Figure 12).

Figure 12: Capelin. Catch advice according to the HCR for initial TAC, based on the relationship between final TAC and estimated number of immature capelin the previous autumn. The figure shows the estimated final TAC (black unbroken line) and the initial (preliminary) TAC (blue dashed line). The latter is set using a Utrigger (red vertical line) of 50 billion immature fish, with a cap on the initial (preliminary) TAC of 400 kt. The green lines show the index value from the autumn survey 2024, with the corresponding initial TAC for 2025/2026 shown on the y-axis.

Intermediate advice 2025/2026

The results of the acoustic measurements in autumn 2025 (see section Section 4.2) on biomass of the mature part of the stock and accounting for the results of the predation model indicates that the goal of the harvest control rule of leaving at least 114 000 t for spawning with a 95% probability would be met with a catch of 65 650 tonnes. With the added precaution from the amended HCR (of setting TAC at 2/3 of that according to original rule), 43 766 tonnes was advised as the intermediate TAC for the fishing season starting 15 October 2025 to 15 April 2026.

Final advice 2025/2026

The final advice derives from a combination of the autumn (weighted 1/3) and the winter measurements (weighted 2/3), both of which are considered to have covered the stock’s distribution area adequately. Considering the combined measurements (Table 5), the estimated predation on the capelin stock, and the coastal states harvest control rule, the final catch advice for the 2025/2026 fishing year should not exceed 197474 tonnes.

It is unclear whether the capelin there will migrate westwards and spawn west of Iceland, spawn north of Iceland, or follow the traditional spawning route east of Iceland, and the MFRI will explore that with a survey in February. Until more is known about the migration route that the capelin observed in the north and northwest of Iceland will take towards spawning grounds, the MFRI proposes that the fishery will also take place north of Iceland instead of exclusively on the part of the stock currently east of Iceland, to avoid a risk of a loss in the diversity of the stock components (e.g. spawning locations).

Table 5: Capelin. Assessment and advice for capelin in the IEGJM area for 2025/2026. Fishable stock and CV the coefficient of variance of the survey estimates of the fish stock size. The advice is based on the predation model in the HCR.
Autumn(Figure 3) January (Figure 8) Total Advice
Fishable stock (thousand tonnes) 418 000 710 200 612 666 197474
CV 0.20 0.24 NA
Surveyed area East Greenland & North Iceland Northwest to southeast of Iceland NA

Benchmark history

Since early 1980s the stock was managed according to an escapement strategy, leaving 400 000 tonnes for spawning. Uncertainty of the estimates was not considered.

A new HCR and management plan were developed at an ICES benchmark meeting in 2015 and adopted the same year (ICES, 2015). The main changes involved accounting for uncertainty in the measurements and in the predation on the capelin stock up to the spawning period. At the ICES benchmark meeting in 2022 (ICES, 2023), minor adjustments were made, which the coastal states meeting agreed to base the advice on. Among other things, these changes included lowering the Blim from 150 000 tonnes to 114 000 tonnes (Figure 13).

Figure 13: Capelin. Initial TAC, agreed final TAC, and catch as reported to ICES.

Reference points

Blim was set at 114 000 tonnes by WKCAPELIN (ICES, 2023). No other reference points are defined for this stock.

State of the stock

The mature part of the stock (or the fishable stock) was estimated to a median of 418 000 tonnes in autumn 2025 and 710 200 tonnes in January 2026. The predation model (ICES, 2015), accounting for catches and predation by cod, saithe and haddock between surveys and spawning, estimated SSB to 266 410 tonnes which were left for spawning in spring 2026 (Table 4). Given the uncertainty estimates, there was 95% probability that at least 114 000 tonnes was left for spawning, if the catches taken amounted to 197 474 tonnes. The acoustic estimate of immature capelin from the autumn survey in autumn 2025 was 118.9 billion. Initial advice for the fishing season 2026/27 on the basis of that amount will be issued by ICES and MFRI in June 2026.

Figure 14: Capelin. Index of immature capelin from acoustic surveys in autumn since 1981.

The estimated SSB at spawning time (March-April) has been recompiled for 1981-2025 (Figure 15), using the model adopted in 2015 and 2023, i.e. taking into account uncertainty in the acoustic measurements and using the predation model adopted in 2015. Uncertainty in acoustic measurements was recompiled for the years 2002-2006 and 2012-2014 by recalculating the acoustic indices and bootstrapping the results. Additionally, uncertainty was available for the years since 2015 when the advice was given based on the new HCR. For earlier years, the CV in the acoustic measurements was estimated by looking at survey reports as well as text from (Vilhjálmsson, 1994). The estimated CV was in the range of 0.15-0.25 and was included as a lognormal multiplier on available average values from the same sources.

Figure 15: Capelin. Median, 5th and 95th percentile of SSB distribution at spawning time (March–April) since 1981. Blim = 114 kt.

Uncertainties in assessment and forecast

The uncertainty of the assessment and forecast depends largely on the quality of the acoustic surveys in terms of coverage, conditions for acoustic measurements and the aggregation of capelin (i.e., high patchiness leads to high variance).

The uncertainty is estimated by bootstrapping (see WKICE 2015). The CV for the immature abundance was estimated to 0.11 in the 2025 autumn survey. The survey had a relatively high coefficient of variation (CV=0.2) for the mature stock estimate. The spatial coverage of the autumn survey in 2025 is considered to have covered the distribution area of the stock. There is some uncertainty regarding the distribution of immature capelin in the autumn survey due to the lack of calibration of the 18kHz on the r/v Tarajoq and therefore difficulties to separate immature capelin from 0-group. However, this uncertainty does not affect the assessment results regarding the estimate of the mature stock.

There was a considerable difference between the point estimates of the two measurements of the stock that the final advice relies on, i.e. 418 000 tonnes in autumn 2025 and 710 200 tonnes in January 2026. Considering the estimated coefficient of variation (CV) of the measurements (=0.2 and 0.24, respectively), the difference is relatively small (the interval of the estimations being 334 to 502 kt vs 540 to 881 kt). This difference could be related to numbers of factors such as: (a) The autumn estimate is heavily influenced by the proportion of immature and mature capelin as determined from the biological samples, and any small bias there will impact the proportions, especially in years when the number of immature is high as in 2025. (b) There are sources of uncertainty not accounted for in the CV estimation such as most likely seasonal difference in acoustical properties of capelin that are not accounted for using a fixed target strength relationship. (c) Some measurements were taken by fishing vessels traveling in the same direction as the migration, while others were taken by research vessels traveling against the migration. This directional difference introduces bias and uncertainty that cannot be easily quantified

While the autumn survey was affected by time constraints the distribution of immature and mature components of the capelin stock seemed to have been covered. However, in light of the results of the winter estimates there is still room for uncertainty towards the Iceland Sea and the north of Iceland.

The role of capelin in the ecosystem

Capelin is an important forage fish and its dynamics are expected to have implications on the productivity of their predators.

The importance of capelin in the East Greenlandic marine ecossytem is not well documented. However, the research effort has increased considerably during autumn surveys towards evaluation of capelin’s role in the ecosystem e.g. by research on feeding of capelin, estimates of prey availability, predators’ distributions and environmental monitoring.

In Icelandic waters, capelin is the main single item in the diet of Icelandic cod, a key prey to several species of marine mammals and seabirds and also important as food for several other commercial fish species (see e.g. Vilhjálmsson, 2002, Singh et al., 2023). Diet studies of cod from the groundfish survey in March clearly demonstrate the importance of capelin in its diet, while also showing the variability in capelin availability between years (Figure 16).

Figure 16: Capelin. The share of capelin food for cod in the population measurement of demersal fish (SMB, takes place at the same time as the capelin spawns) in March 1993–2025, shown as a relative capelin fill based on stomach samples (yellow and red when the share of capelin is high).

Regulations and their effects

Over the years, the fishery has been closed during April–late June and the season has started in July/August or later, depending on the state of the stock.

Areas with high abundances of juvenile age 1 and 2 capelin (on the shelf region off NW-, N- and NE-Iceland) have usually been closed to the summer and autumn fishery.

It is permissible to transfer catches from the purse seine of one vessel to another vessel, in order to avoid slippage. However, if the catches are beyond the carrying capacity of the vessel and no other vessel is nearby, slippage is allowed. In recent years, reporting of such slippage has not been frequent. Industrial trawlers do not have the permission to slip capelin in order to harmonize catches to processing.

In Icelandic waters, fishing with pelagic trawl is only allowed in limited area off the NE-coast (fishing in January) to protect juvenile capelin and to reduce the risk of affecting the spawning migration route (shuttering of migrating capelin schools by pelagic trawling has been hypothesized).

As a precautionary measure to protect juvenile capelin, the coastal states (Iceland, Greenland and Norway) agreed that fishing shall not start until 15. October(in affect since 2021).

References

Anon. 2015. Agreed Record of Conclusions of Coastal State consultations on the management of the capelin stock in the Iceland–East Greenland–Jan Mayen area. 2015. Reykjavík, Iceland. 7–8 May 2015. https://www.regjeringen.no/contentassets/37b66bdf33d84e99924bb27553641719/samledokument-lodde-mai-2015---agreed-records---bilateral-avtale.pdf Last accessed: 31 May 2025.

Anon. 2023. Framework arrangement between Greenland and Iceland on the conservation and management of capelin. 2023. Reykjávik, Iceland 3 July 2023. 4 pp. https://www.althingi.is/altext/pdf/154/fylgiskjol/s1655-f_I.pdf Last accessed: 31 May 2025.

Bardarson, B, Heilman, L, Jonsson, SÞ and Jansen, T 2024. Cruise report of acoustic assessment of the Iceland-East Greenland-Jan Mayen capelin stock in the autumn 2024. Kver Hafrannsóknastofnunar. KV2024-10. 18 pp.

Bardarson, B, Gudnason, K, Singh, W, Petursdottir, H, & Jonsson, SÞ (2021). Loðna (Mallotus villosus). Í Guðmundur J. Óskarsson (ritstj.), Staða umhverfis og vistkerfa í hafinu við Ísland og horfur næstu áratuga. Haf- og vatnarannsóknir, HV 2021-14, 31–34.

Christiansen, JS, Præbel, K, Siikavuopio, SI, Carscadden, JE 2008. Facultative semelparity in capelin Mallotus villosus (Osmeridae)-an experimental test of a life history phenomenon in a sub-arctic fish, Journal of Experimental Marine Biology and Ecology, Volume 360, Issue 1, 2008, Pages 47-55, ISSN 0022-0981, https://doi.org/10.1016/j.jembe.2008.04.003.

Engilbertsson, V, Óskarsson, GJ and Marteinsdóttir, G (2012). Inter-annual Variation in Fat Content of the Icelandic Capelin. ICES CM 2013/N:26.

Gjøsæter, H, Bogstad, B, and Tjelmeland, S 2002. Assessment methodology for Barents Sea capelin, Mallotus villosus (Müller). – ICES Journal of Marine Science, 59: 1086–1095.

Gudmundsdottir, A, and Vilhjálmsson, H 2002. Predicting Total Allowable Catches for Icelandic capelin, 1978–2001. ICES Journal of Marine Science, 59: 1105–1115.

Gudmundsdottir, A, and Sigurdsson, Th 2014. Growth of capelin in the Iceland-East Greenland-Jan Mayen area. NWWG 2014/WD:29.

ICES. 2015. Report of the Benchmark Workshop on Icelandic Stocks (WKICE), 26-30 January, 2015. ICES Headquarters. ICES CM 2015/ACOM:31. 335 pp.https://doi.org/10.17895/ices.pub.5295

ICES. 2023. Benchmark workshop on capelin (WKCAPELIN). ICES Scientific Reports. 5:62. 282 pp. https://doi.org/ices.pub.23260388

ICES 2024. Capelin (Mallotus villosus) in subareas 5 and 14 and Division 2.a west of 5°W (Iceland and Faroes grounds, East Greenland, Jan Mayen area). ICES Advice: Recurrent Advice. Report. https://doi.org/10.17895/ices.advice.25663980.v1

Jansen, T, Hansen, FT, Bardarson, B 2021. Larval drift dynamics, thermal conditions and the shift in juvenile capelin distribution and recruitment success around Iceland and East Greenland. Fisheries Research, 236.

MFRI. 2024. State of Marine Stocks and Advice 2024, advice on capelin. Marine and Freshwater Research Institute, 11 October 2024.

Singh, W, Ólafsdóttir, AH, Jónsson, SÞ, Óskarsson, GJ 2023. Capelin in a changing environment. Haf- og vatnarannsóknir, HV 2023-43. https://www.hafogvatn.is/static/research/files/capelin_2023_eng.pdf

Vilhjálmsson, H 1994. The Icelandic capelin stock. Capelin, Mallotus villosus (Müller), in the Iceland– Greenland–Jan Mayen area. Rit Fiskideildar, 13: 281 pp.

Vilhjálmsson, H 2002. Capelin (Mallotus villosus) in the Iceland–East Greenland–Jan Mayen ecosystem. ICES Journal of Marine Science: Journal du Conseil, 59: 870–883.

Vilhjálmsson, H 2007. Impact of changes in natural conditions on ocean resources. Law, science and ocean management 11, 225.