COD

Gadus morhua


Assessment report
Published by

Marine and Freshwater Research Institute, Iceland

Published

12 June 2026

Key signals

  • Survey biomass increased steadily from 2008 to 2012, after which high but variable levels were observed in both the spring and autumn surveys. Since 2012, discrepancies have emerged between the two surveys: the spring survey shows a stronger upward trend, while the autumn survey indicates more stable or modest increases. The most recent spring survey, however, shows a marked decline in biomass.

  • Recruitment (age 3) was substantially higher prior to 1985 but has remained relatively stable over the past decade. The year classes 2020–2022, recruiting in 2023–2025, are at or below the long-term average, suggesting a likely decline in reference biomass as these cohorts reach age 4. Several of these cohorts also exhibit low stock and catch weights at ages 4–7, which make up the bulk of the reference biomass.

  • Harvest rates exceeded the management target of 0.2 prior to 2022 but have since fluctuated around the target level.

  • Length distributions have been stable over the past decade, reflecting periodic recruitment and a broad range of sizes in the population. However, the abundance of fish in the <50 cm is lower than in most recent years, supporting expectations of reduced biomass in the near term.

  • Spawning stock biomass (SSB) peaked in 2018–2019, reaching its highest level since before 1970. Although SSB is now declining, it remains relatively high compared to most levels observed since 1980.

General information

Cod (Gadus morhua) is widely distributed in Icelandic waters, with the highest abundance found on the northwestern, northern, and northeastern parts of the continental shelf. As a demersal species, cod occupies a wide depth range, typically from a few meters down to 600 m, and occasionally deeper. Adult cod are not strongly selective regarding bottom substrate and can be found on a variety of seabed types. In contrast, juveniles prefer moderately sheltered, shallow habitats such as kelp forests and seagrass beds. Cod thrive in sea temperatures around 4–7°C, although they are frequently caught in waters below 2°C.

Cod spawn around the Icelandic coastline in distinct regional spawning components. The primary spawning areas are located in the south, southwest, and west, where spawning begins early in spring (March–April) in warmer waters. In recent years, spawning activity has shifted westward (Jónsdóttir et al. (2025)). Historically, spawning occurred later in the colder northern waters, but the spawning period there has advanced considerably. Pelagic eggs and larvae drift predominantly northward and eastward, following a clockwise pattern to nursery areas in the north and northeast. Adult cod undertake feeding migrations to deeper waters in the northwest and southeast, although some remain in shallow areas to feed. Cod is Iceland’s most significant groundfish species in terms of commercial importance.

Fishery

Landing trends

Cod landings from Iceland waters have been consistently high since records began in 1903, typically ranging from 300 to 450 thousand tonnes prior to World War II and again between 1950 and 1990 (Figure 1). During the World Wars, foreign fleets ceased operations in Icelandic waters, while Icelandic catches remained stable. Throughout much of the 20th century, foreign vessels accounted for a significant share of the catch until Iceland extended its Exclusive Economic Zone (EEZ) to 200 miles in 1976.

Catch levels have largely been shaped by stock productivity, influenced by both recruitment and immigration from Greenland. Significant migration events from Greenland to Iceland occurred in the 1930s and in 1953. A reduction in fishing effort during World War II also contributed to stock rebuilding.

Between 1955 and 1990, landings gradually declined. From 1992 onward, average catches have been around 219 thousand tonnes (range: 148–270 thousand tonnes). In 2025, landings totaled 218833 tonnes. A small share of this (2408 tonnes) was landed by Norwegian and Faroese vessels under bilateral agreements (Figure 1).

Historically, bottom trawl and gillnets were the primary gear types (Figure 2). Bottom trawl has consistently made up at least 40% of catches, rising to about 55% in recent years, while gillnet use declined from 20% before 2001 to around 7% more recently. Most bottom trawl catches occur in the northwest, while gillnet catches have been concentrated in the south and west during spawning. The share of longline catches has increased over time, with large longline vessels with automatic baiting extending the fishery into deeper waters. Before 2003, longlines accounted for about 20% of catches; this rose to around 35% during 2005–2016. Demersal seines have contributed a steady 5–8% of total catches. In some regions, especially the northwest and southeast, cod aggregate in dense schools, allowing captains to quickly fill quotas, particularly prior to landing. Cod condition and size, along with proximity to landing ports, also influence fishing locations.

In 2025, bottom trawls accounted for more than half of total catches (57%), followed by longlines (22%), gillnets (7%), jiggers (7%), and demersal seines (7%). The largest proportion of the catches were taken from the western and northwestern regions, followed by the northeast and southwest. Catches occurred at similar depths as in previous years, although slightly shallower overall (Figure 2).

The depth distribution of the fishery has shown little change (Figure 3).

Figure 1: Cod in Division 5.a. Recorded landings since 1903.
Figure 2: Cod in Division 5.a. Landings in tons and percent of total by gear and year
Figure 3: Cod in Division 5.a. Depth distribution of cod catches from bottom trawls, longlines, trawls and demersal seine from Icelandic logbooks

Due to its wide distribution, cod is fished across the Icelandic shelf using various gear types (Figure 4, Figure 5, Figure 6). Demersal trawl is the main fishing gear (Figure 4), with primary fishing areas located in deeper, colder waters offshore in the northwest, northeast, and east. Over recent years, trawl effort has increasingly concentrated in these hotspots.

Longlines account for the second-largest share of cod catches and are widely used around the shelf, with the lowest effort on the southern and southeastern coasts (Figure 5). The spatial pattern of longline catches has remained generally consistent, with periodic hotspots. Gillnets, demersal seines, and jiggers contribute smaller shares and primarily operate in shallower waters (Figure 6).

Since 2000, the share of cod catches from the northwestern area increased from about 35% to 40–50% in 2011–2024 (Figure 7 and Figure 8 ). In contrast, catches west of Iceland declined from 25–30% to just under 20%, and from the southeast, from 5–10% to below 5%. Other areas have remained stable, with the northeast contributing around 20% and the southwest about 10%.

The number of vessels accounting for 95% of annual cod landings declined from around 1000 to 750 during 1994–1999, despite a notable increase in total catch (Figure 9). Between 1999 and 2008, vessel numbers declined further to below 400, in line with reduced catches. After a temporary increase during 2009–2014, the number of vessels has since decreased to around 300. This trend is evident across all fleet segments (Table 1).

Figure 4: Cod in Division 5.a. Spatial distribution of catches by demersal trawls.
Figure 5: Cod in Division 5.a. Spatial distribution of catches by longlines.
Figure 6: Cod in Division 5.a. Spatial distribution of catches by gillnets, demersal seine, and jiggers.
Figure 7: Cod in Division 5.a. Changes in spatial distribution of cod catches as recorded in Icelandic logbooks.
Figure 8: Cod in Division 5.a. Spatial distribution of catches by all gears for selected years.
Figure 9: Cod in Division 5.a. Number of vessels (all gear types) accounting for 95% of the total catch annually since 1994. Left: Plotted against year. Right: Plotted against total catch. Data from the Directorate of Fisheries.
Table 1: Cod in Division 5.a. Number of Icelandic vessels landing cod, and all landed catch divided by gear type.
Year
Bottom trawl
Long lines
Other gears
Total
Vessel (number) Catch (tonnes) Vessel (number) Catch (tonnes) Vessel (number) Catch (tonnes) Catch (tonnes)
2000 183 103 558 530 49 946 827 17 623 186 057
2001 160 99 071 515 47 172 766 17 002 180 260
2002 155 87 885 450 42 405 724 19 305 163 179
2003 147 88 422 461 44 654 721 16 026 162 477
2004 135 95 769 470 57 397 722 14 840 182 234
2005 134 84 018 463 69 444 604 8 106 174 338
2006 126 82 417 447 71 037 509 5 859 169 671
2007 123 71 499 425 58 943 473 4 397 143 550
2008 113 58 172 370 53 843 427 4 151 124 607
2009 113 79 667 336 61 005 798 8 190 159 232
2010 111 75 609 286 57 491 1 008 9 372 150 768
2011 110 73 538 290 57 711 1 061 12 665 153 020
2012 118 85 265 305 67 777 1 099 13 417 176 448
2013 110 101 453 297 74 835 1 054 15 237 201 617
2014 110 95 830 292 77 807 1 012 16 355 200 399
2015 103 103 530 266 79 244 943 13 957 208 669
2016 99 111 016 246 84 509 956 15 299 226 754
2017 94 117 891 221 75 244 832 14 945 223 478
2018 83 135 030 201 78 316 813 16 221 245 385
2019 81 135 661 190 78 326 794 13 592 241 760
2020 81 146 788 158 68 103 839 15 884 246 973
2021 87 140 773 146 69 632 841 16 014 244 114
2022 83 124 950 121 62 795 850 15 172 219 413
2023 81 117 580 99 54 527 866 13 389 201 511
2024 79 123 832 90 49 139 849 15 238 203 602

Catch per unit of effort from commercial fisheries

Catch per unit of effort (CPUE) data (Figure 10) indicate a steady increase since 1990 for the main gear types in hauls where cod accounts for more than 50% of the catch. Overall CPUE across all gears is among the highest on record. CPUE could not be estimated after 2021 due to missing effort data for several years.

Figure 10: Cod in Division 5.a. Catch per unit of effort in the most important gear types. The dashed lines are based on locations where more than 50% of the catch is cod and solid lines on all records where cod is caught. A change occurred in the longline fleet starting September 1999. Earlier only vessels larger than 10 BRT were required to return logbooks but later all vessels were required to return logbooks. Data are excluded for years after 2021 for gillnets and longlines due to effort data inconsistencies.

Landings and discards

Landings data before 1982 (and foreign landings until 2005) are sourced from the ICES STATLANT database. Icelandic landings between 1982–1993 were collected by the Fisheries Association of Iceland, and from 1994 onward by the Directorate of Fisheries. Foreign landings were recorded by the Coast Guard before 2014 and by the Directorate thereafter.

Discarding is prohibited by law. Management measures, such as inter-species quota transfers and landing flexibility, discourage discarding. To help prevent high grading and quota mismatches, fisheries are permitted to land catches that are exempt from quota deductions, provided that the proceeds from their sale are transferred to a government-managed fund. More information is available at https://www.responsiblefisheries.is/seafood-industry/fisheries-management.

Figure 11: Cod in Division 5.a. Estimates of annual discards by gear (point estimates and 95% confidence interval). No estimates are available after 2017.

Data and sampling

Commercial data

Sampling coverage from commercial catches is generally good for the main gears (demersal seines, longlines, gillnets, bottom trawls), with broad spatial and seasonal representation (Figure 12, Figure 13).

Figure 12: Cod in Division 5.a. Ratio of samples by month (bars) compared with proportion landings by month (solid black line) split by year and main gear types. Numbers of above the bars indicate number of samples by year, month and gear.
Figure 13: Cod in Division 5.a. Fishing grounds last year as reported in logbooks (contours) and positions of samples taken from landings (crosses) by main gear types.

Length compositions

The length distribution of landed cod has shifted toward larger fish over the past decade (Figure 14). Most length data come from bottom trawl, longline, gillnet, and demersal seine fleets (Table 2). Gear-specific sample sizes have varied with fleet composition.

Figure 14: Cod in Division 5.a. Commercial length distributions by gear and year
Table 2: Cod in Division 5.a. Number of samples and length measurements from landed catch.
Year
Bottom Trawl
Danish Seine
Gillnets
Long Line
Num. samples Num. lengths Num. samples Num. lengths Num. samples Num. lengths Num. samples Num. lengths
2000 766 172 132 23 3 265 27 4 517 124 29 780
2001 1 131 170 398 79 13 660 541 39 836 281 39 915
2002 1 233 162 365 122 19 057 443 45 520 338 46 560
2003 1 131 114 366 73 13 283 512 32 729 444 67 124
2004 1 239 107 977 97 17 943 310 28 422 467 85 952
2005 1 092 101 166 298 18 050 267 37 554 549 108 597
2006 859 79 264 159 15 812 349 34 329 776 115 401
2007 946 75 259 416 16 252 304 24 024 498 96 662
2008 849 67 630 297 14 065 370 23 676 530 105 864
2009 884 76 100 216 15 306 205 25 436 420 86 909
2010 806 77 979 139 10 621 152 26 303 401 81 373
2011 596 64 643 86 6 604 162 29 203 280 55 614
2012 604 54 037 104 8 282 131 22 678 438 97 729
2013 659 73 853 50 2 196 25 3 532 393 83 001
2014 531 46 615 40 5 118 141 27 103 453 96 534
2015 554 65 641 47 5 880 56 5 860 376 83 342
2016 493 57 116 51 6 201 150 25 919 421 96 525
2017 518 67 512 61 7 073 47 7 149 368 77 691
2018 264 48 111 46 5 222 114 15 746 395 74 874
2019 451 81 165 49 4 679 43 5 754 292 56 710
2020 191 35 494 27 3 038 89 12 469 84 13 242
2021 325 53 645 48 5 014 13 1 453 38 4 333
2022 228 38 180 49 5 336 9 961 52 11 348
2023 150 23 230 44 3 854 81 9 659 34 4 187
2024 246 43 591 36 4 161 21 1 987 45 6 816
2025 289 50 487 47 5 532 25 3 019 37 4 818

Age compositions

Table 3 presents the number of otolith samples and age readings by gear type, while Figure 13 shows the sampling locations.

Over the past few decades, the age composition of the catch has shifted toward older fish, likely due to reduced fishing pressure (Figure 15). In recent years, the number of year classes represented in the catch has increased, reflecting sustained low fishing mortality (Figure 16).

Table 3: Cod in Division 5.a. Number of samples and otoliths collected from landed catch.
Year
Bottom Trawl
Danish Seine
Gillnets
Long Line
Num. samples Num. otoliths Num. samples Num. otoliths Num. samples Num. otoliths Num. samples Num. otoliths
2000 205 10 034 18 885 21 1 051 44 2 223
2001 515 9 193 10 500 288 2 239 136 2 830
2002 587 8 612 30 693 226 2 055 162 2 815
2003 684 8 144 9 450 308 1 217 170 3 409
2004 824 9 052 8 400 90 802 100 2 297
2005 654 6 485 208 788 12 598 103 3 548
2006 529 5 720 71 931 102 1 471 271 3 507
2007 625 6 094 328 1 244 125 1 203 82 3 650
2008 543 5 024 217 816 196 1 029 65 2 771
2009 569 5 417 136 561 23 1 150 33 1 650
2010 493 5 880 83 501 16 799 59 2 931
2011 340 5 339 49 578 14 700 46 2 294
2012 403 5 757 63 688 21 1 031 73 3 209
2013 375 6 192 39 397 21 1 050 62 3 065
2014 378 5 102 20 525 29 850 65 1 856
2015 312 4 937 29 708 45 917 54 1 467
2016 320 5 015 41 1 025 41 1 025 60 1 544
2017 236 3 817 39 975 26 644 46 1 119
2018 92 2 369 30 750 16 400 39 945
2019 113 2 828 27 675 12 300 50 1 237
2020 73 1 847 21 520 12 300 31 775
2021 85 2 171 34 850 8 200 30 750
2022 57 1 264 16 320 2 40 18 362
2023 79 1 511 28 560 6 118 22 440
2024 91 1 871 31 620 5 100 22 440
2025 94 1 916 30 600 5 100 17 340
Figure 15: Cod in Division 5.a. Catch at age from the commercial fishery in Iceland waters. Bar size is indicative of the catch in numbers and bars are colored by cohort.
Figure 16: Cod in Division 5.a. Catch at age from the commercial fishery in Iceland waters. Proportion biomass caught by year and age, bars are colored by cohort.

Weight at age in the catch

Mean weight at age in the catch (Figure 17) declined from 2001 to 2007, reaching historical lows in many age groups. Although mean weights increased in subsequent years, nearly all age classes were at least slightly below the 1985–present average in both this year and the previous year. For 2026, mean weights for ages 3–9 are estimated using the relationship between spring survey weights and commercial weights from the preceding year. Weights for older fish are assumed to remain unchanged from the previous year (see section on short-term projections).

Figure 17: Cod in Division 5.a. Mean weight at age in the catch from the commercial fishery in Icelandic waters. Bars are coloured by cohort.

Survey data

The Icelandic spring groundfish survey (hereafter spring survey) has been conducted annually in March since 1985. An additional survey, the Icelandic autumn groundfish survey (autumn survey), was initiated in 1996. However, a full autumn survey was not carried out in 2011.

Figure 18 presents a recruitment index based on cod smaller than 55 cm, alongside trends in various biomass indices. Survey abundance by tow location is shown in Figure 19, while changes in spatial distribution are illustrated in Figure 20.

The total biomass index from the spring survey has remained relatively high since 2012 but has shown an overall declining trend over the past decade. Both spring and autumn survey indices declined markedly from their 2017 peak to 2020, followed by a slight increase during 2021-2024 (Figure 18). While spring survey measurements in 2021 and 2022 were similar to those in 2018 and 2019, the autumn survey index in 2021 declined further, reaching its lowest level since 2004. The 2020 survey indices were considerably below expectations for the size classes making up the majority of the fishable biomass, a trend that continued in the 2021 autumn survey but not in the 2021 spring survey.

Overall, both surveys have shown similar long-term trends (Figure 18), although fluctuations since the late 2000s have been more pronounced in the autumn survey. The discrepancy between spring and autumn biomass measurements reached a record high in 2021 and remains the largest observed since 2000. However, the recent decline in the spring survey index, combined with a stabilization in the autumn index, has narrowed this gap in the most recent survey year.

In the spring survey of 2026, cod were caught throughout Icelandic waters, with hotspots observed offshore in the northwest, southeast, and in shallow southern waters (Figure 19). Biomass along the western continental slope was similar to the previous year. The spatial distribution of the total biomass index consistently shows the north (N), northwest (NW) and northeast (NE) areas dominating across years (Figure 20). The spatial distribution of cod in the autumn survey of 2025 was similar to previous years, with the majority of biomass measured on traditional fishing grounds in the northwest (NW) and north (N) regions (Figure 20). However, recent years have seen some shifts, with the spring survey showing declining biomass in the NE and increases in the west and southeast (SE). In the same time period, the autumn survey shows an increase the northwest, both deep (dNW) and shallower areas (NW), as well as in the west (W). In 2026, biomass decreased in most areas.

Length distributions from both surveys clearly show distinct modes for the youngest age groups (Figure 21). In older age groups, separation becomes less distinct due to individual variability in growth and maturity, though modes corresponding to 2- and 3-year-old fish can sometimes be identified.

Survey age-based indices for older fish have remained relatively high over the past decade, despite the fact that many of these cohorts showed only low to moderate indices at younger ages (Figure 22). The 2020 spring survey anomaly is particularly evident — e.g., the 2014 and 2015 year classes were around the long-term average in 2019 (as 4- and 5-year-olds), but dropped to roughly half that in 2020 (as 5- and 6-year-olds). In 2021, the 2015 cohort appeared well above average in both survey and catch-at-age data, a trend that continued in subsequent years and suggests likely immigration from Greenland waters.

Figure 18: Cod in Division 5.a. Indices (total biomass, biomass > 55 cm, biomass > 80 cm and abundance ≤55 cm) in the Spring Survey (March) 1985 and onwards (line shaded area) and the autumn survey (point ranges).
Figure 19: Cod in Division 5.a. Location of cod in the 2024 March (SMB) and the 2023 Autumn (SMH) surveys, bubble sizes are relative to catch sizes, and crosses indicate stations where no cod was observed.
Figure 20: Cod in Division 5.a. Changes in geographical distribution of the survey biomass.
Figure 21: Cod in Division 5.a. Length disaggregated abundance indices from the March and Autumn surveys.
Figure 22: Cod in Division 5.a. Age disaggregated indices in the Spring Survey (left) and the autumn survey (rights). Note different scales on y-axes.

Stock weight at age

Mean weights in the spring survey for all cod age groups were below average during approximately 2000–2010 (Figure 23). Following this period, mean weights for ages 5–10 were generally above average for several years. However, in the past two years, mean weights have declined across both younger and older age groups.

Figure 23: Cod in Division 5.a. Stock weights from the March survey in Icelandic waters. Bars are coloured by cohort.

Stock maturity at age

Maturity-at-age data from the spring survey are presented in Figure 24. In recent decades, maturity at younger ages has generally been below average, indicating a trend toward later maturation.

Figure 24: Cod in Division 5.a. Maturity at age in the survey. Bars are coloured by cohort. The values are used to calculate the spawning stock.

Stock assessment

Model and data inputs

The assessment is based on a separable statistical catch-at-age model (commonly referred to as MUPPET, see H. Björnsson, Hjörleifsson, and Elvarsson (2019)), which assumes constant selectivity within four time periods. The most recent period spans from 2007 to the present. Survey residuals are modeled using a multivariate normal distribution to account for potential year effects — an approach implemented since 2002. The model is a statistical cohort framework in which fishing mortality can change gradually over time, constrained by a random walk. This same framework is used to project stock dynamics for estimating reference points and evaluating the harvest control rule (HCR). It was benchmarked in 2021 as part of the HCR evaluation (ICES (2021b)).

In the current assessment, the model configuration was updated to account for a likely migration event. The 2015 year class appeared in 2021 at age 6 in higher numbers than would be expected based on earlier observations. To address this, an additional parameter was included beginning with the 2025 assessment to estimate recruitment at age 6 in 2021 — representing the 13th such migration event accounted for since the model’s starting year of 1955.

The assessment relies on four primary data sources: two groundfish surveys (spring and autumn), commercial samples, and landings. Commercial data are used to construct catch-at-age estimates, which enter the likelihood function alongside age-specific survey indices from both surveys. Stock weights and catch weights at age are derived from the spring survey and commercial catches, respectively, while maturity-at-age data are obtained from the spring survey. Prior to the start of the spring survey in 1985, stock weights and maturity were assumed constant at their 1985 values.

A detailed description of data preparation for both tuning and input is provided in the stock annex (ICES (2021a)), and all input data are available on the MFRI website (www.hafogvatn.is).

The input to the analytical age-based assessment consists of catch-at-age data from 1955 to 2025 (ages 3–14), spring survey data (SMB) from 1985 to 2026 (ages 1–14), and autumn survey data (SMH) from 1996 to 2025 (ages 3–13). Catch-at-age data are derived based on 20 metiers, combining two areas (north and south), two seasons (January–May and June–December), and five fleets (bottom trawl, longline, handline/jiggers, gillnet, and Danish seine).

The reference biomass (age 4+) used to set the TAC for the upcoming fishing year is calculated as the product of population numbers at the beginning of the assessment year and catch weights for that year. Since catch weights for 2026 are not yet known, they must be predicted from stock weights measured in the spring survey, using a relationship established from the previous year’s data.

Mean weight at age in the catch (Figure 17) declined between 2001 and 2007, reaching historical lows in many age groups. The observed variation in catch weights at age partly reflects underlying variability in stock weights, as indicated by survey measurements (Figure 23).

No direct information is available on natural mortality. For assessment and advisory purposes, a fixed natural mortality rate of 0.2 is assumed for all age groups.

Diagnostics and fit

The diagnostics (Figure 25) reveal large negative residuals in the 2020 spring survey for the key age groups (ages 4 to 8), along with smaller negative residuals in the surrounding the years, 2019 and 2021, particularly in the autumn survey. A summary diagnostic comparing observed and predicted survey biomass (Figure 26) highlights discrepancies between model estimates and survey point estimates. There are indications that interannual variability in survey measurements has increased in recent years in both surveys, relative to earlier periods.

Figure 25: Cod in Division 5.a. Residuals from the model fit to survey and catch data based on the both the surveys. Red circles indicate negative residuals (observed < modelled), while blue postive. Residuals are proportional to the area of the circles.
Figure 26: Cod in Division 5.a. Aggregated model fit to the total biomass indices. Note that residual correlation is estimated (see text for further details).

Results

The results of this year’s assessment estimate the spawning stock biomass (SSB) for the assessment year at 371 thousand tonnes. The estimated SSB in recent years is higher than any values observed over the past five decades. The reference biomass for 2026 is estimated at 997633 t, and the harvest rate for 2025 is estimated at 0.198.

Year classes since the mid-1980s are estimated to be relatively stable, but with a mean approximately 35% lower than that observed during 1955–1985. Assessment results are summarized in Table 4 and Figure 27, and are also available on the MFRI website (www.hafogvatn.is).

Reference biomass has remained stable in recent years. However, the estimates for the 2021 and 2022 year classes have not been revised upward from the relatively low values reported last year (close to 100 million). These cohorts are expected to form a substantial part of the fishable stock in 2026–2027, suggesting a potential decline in fishable biomass during that period. Moreover, the most recent recruitment estimate (2023 year class) is only slightly higher and remains below the past decade’s average, indicating that the decline in reference biomass could continue into 2028, unless future recruitment estimates are revised upward.

Estimated spawning stock biomass (SSB), although variable, increased to a peak in 2017, the highest level observed in nearly 60 years. Since the most recent revision of the harvest control rule, the harvest rate has declined. Given that recruitment since 1988 has been substantially lower than the average observed during 1955–1985, the increase in SSB was primarily driven by lower harvest rate.

In 2023, the harvest rate reached its lowest level in the assessment period. However, due to the decline in stock and catch weights during the past year, a greater number of cod will be required to fill the current TAC compared to previous years. As a result, the harvest rate has increased over the last year.

This rise in fishing mortality, combined with the potential for elevated natural mortality due to lower energy reserves and increased predation on recruiting age groups (B. Björnsson, Sólmundsson, and Woods 2022), could increase the risk of overestimating stock size in projections. This potential overestimation, along with recent recruitment levels falling below the past decade’s average, suggests a continued decline in biomass is likely in the short term.

Figure 27: Cod in Division 5.a. Summary from assessment. Dashed vertical line indicates the assessment year and yellow shaded region the uncertainty as estimated by the model. Solid horizontal line in SSB panel indicates B_lim; dashed horizontal line indicates B_trigger. Solid horizontal line in HR panel indicates HR_MSY proxy; dashed line indicates HR_mgt.

Biomass estimates have been revised upwards in each of the past three years, suggesting a slight tendency for the model to underestimate spawning stock biomass (SSB). In the current assessment, the notable upward revisions in SSB for 2021 and subsequent years result from a change in the model configuration to account for a likely migration event. Specifically, an additional parameter was introduced to estimate recruitment to the population at age 6 in 2021.

This migration event was first identified through unexpectedly high numbers of the 2015 year class appearing at age 6 in 2021, a signal that persisted through consecutive years and was consistently detected in all three data sources used in the model. The same 2015 cohort also appears as a large year class in East Greenland catch-at-age and survey data for the East Greenland–Iceland offshore spawning cod stock (ICES stock cod.21.27.1.14), indicating a likely shared origin.

This represents the 13th migration event accounted for in the model since 1958, all of which involved recruitment at ages 6–9 and were most likely associated with immigration from Greenland waters.

In addition to this 13th migration event, fishing activity and catches have increased over the past decade on both the Icelandic and Greenland sides of the EEZ near Dohrn Bank. Currently, the cod stock located on the Greenland side of the EEZ boundary is assessed using landings data only, as attempts to implement a category 1 assessment have not successfully captured trends across most fishing activities in the area. As a result, catch-at-age data are generated as part of the Greenland stock assessment. These data were included in the Icelandic stock assessment as a sensitivity run, both with and without estimation of the 13th migration event.

Omitting the 13th migration from the assessment resulted in a slight upward revision of the 2020 biomass estimate and a marginally poorer model fit. Including catch data from Dohrn Bank generally led to upward revisions of SSB estimates across the period following 2015. When both the migration event and Dohrn Bank data were included, these effects were combined; however, the inclusion of Dohrn Bank data also caused a decline in model fit. As a result, only the estimation of the 13th migration was retained in the final model configuration used for providing advice. The sharp decline in SSB projected for 2025 was consistent across all model runs.

Figure 28: Cod in Division 5.a. Comparison of assessment results (Advice, both surveys) with sensitivity runs, where the Alternative prognosis was used to produce catch advice (only affects terminal year in B4+), additional catches at age were included from Dohrn Bank in Greenland waters, or the 13th migration was left out.

The retrospective pattern of the assessment is shown in Figure 29, along with the Mohn’s rho values. The default 5-year peels resulted in the following values: 0.04 for recruitment, 0.007 for harvest rate, and 0.001 for spawning stock biomass.

Leave-one-out analyses indicate that the assessment aligns most closely with trends in the spring survey. Removing the autumn survey series results in a slight increase in biomass estimates, while removing the spring survey leads to a more substantial increase — similar to the effect of relying on catch data alone (Figure 30).

Figure 29: Cod in Division 5.a. Analytical retrospective analysis of the assessment of cod with a 5 year peel.
Figure 30: Cod in Division 5.a. Comparison of assessment results where either the spring survey, the autumn survey, or both are omitted from the estimation.

Short-term projections

Landings of Icelandic cod in 2025 are estimated at 218833 tonnes, the majority of which were taken by the Icelandic fleet.

To perform short-term projections, an estimate of the catch for the current calendar year is required. This year’s projection assumes that the remainder of the TAC for the current fishing year (ending August 31) will be fully taken, along with an expected 3 thousand tonnes catch by the foreign fleet. The projected stock status for the interim year, along with the projection output, is provided in Table 4.

Mean annual discards of cod during 2001–2012 were approximately 1% of landings by weight. More recent data suggest that discards may have increased slightly (MRI 2016). These discard estimates are based on the assumption that discarding primarily occurs as high-grading.

In line with the management plan, advice for the upcoming fishing year (2026/2027) is based on the biomass of age 4+ cod at the beginning of the calendar year (2026). Because reference biomass is calculated using catch weights, a deterministic projection of catch weight growth is required. In recent years, catch weights at age for age groups 3–9 have been predicted using spring survey weights from the same year, applying a linear relationship (slope and intercept) derived from the previous year’s data. For age groups 10 and older, catch weights from the previous year are carried forward.

The same method was used to estimate weights-at-age for the following year, i.e., \(\alpha\) and \(\beta\) were estimated according to the following equation:

\[ \text{cW}_{a,y-1}=\alpha+\beta\text{sW}_{a,y-1} \]

and catch weights for the assessment year were then estimated according to:

\[\text{cW}_{a,y}=\alpha+\beta\text{sW}_{a,y}\]

where cWa,y denotes the catch weight and sWa,y the stock weight for age a and year y.

Based on this approach, the predicted mean catch weights-at-age in 2026 are below average for most age groups, as both the mean weights in the spring survey and in the catch were below average in 2025, and stock weights were below average this year (Figure 23).

An alternative method, labeled ‘alt’, was also explored. This model predicts catch weight at age using age-specific spring survey weights within each year, based on data from 1990 onwards. It has previously yielded more plausible estimates of catch weights, including in the current assessment year (2026), where the deviation from the standard model was 2.5%.

Retrospective analyses indicate that this alternative model has improved predictive performance, with a lower coefficient of variation (0.035 vs. 0.050) and reduced bias (-0.0020 vs. -0.0049), as shown in Figure 31 and Figure 32.

The alternative model has been discussed by the NWWG in 2022 and subsequent years as a potential improvement over the current SPALY weight prediction model. However, it was agreed that a more extensive evaluation should be conducted before implementation, especially in light of recent changes in cod mean weights. External review, either through a working document or during the next benchmark (anticipated for 2027), would also be beneficial.

Figure 33 shows the contribution of each year-class to the reference stock (B4+). The effects of reduced mean weights are clearly visible there, as for example the biomass of the 2019 year-class is at the average despite having been among the largest since 1985. The year-classes following it are weaker, however, and therefore their biomass is below average.

Figure 31: Cod in Division 5.a. Comparison of the short term prediction of catch weights from stock weights (blue), used in the calculation of reference biomass, using a regression across ages of catch weight on stock weight data observed in 2024 (red). Historical values and a regression based on all years of data represent the long-term average relationship in grey.
Figure 32: Cod in Division 5.a. Comparison of the short term prediction of reference biomass using the standard procedure (spaly) versus an alternate method (alt) to the realised value a year later (black line).
Figure 33: Cod. The upper figure shows the estimated size of year-classes from 1984 at 3 years of age compared to the average of year-classes from 1987 to last year. The lower figure shows the predicted age composition of the reference stock in biomass for this year, compared to the average of the previous 10 years.
Table 4: Cod in division 5.a. Summary of the assessment and results of the short-term projections when the harvest control rule is applied. The assessment includes estimates for spawning stock biomass (SSB), reference biomass (B4+), calendar year catch, harvest rate (HR), and recruitment at age 3. Projections begin with 2026. Fishing year catches are only given for intermediate years and projections.
Year Calendar Year Catch Fishing Year Catch SSB TB B4+ HR Recruit. (age 3)
1955 545 250 — 764 535 1 632 037 2 091 845 0.242 151 049
1956 486 909 — 615 238 1 475 627 1 819 507 0.256 143 790
1957 455 182 — 592 727 1 384 486 1 640 699 0.303 161 494
1958 517 359 — 705 112 1 448 341 1 651 300 0.290 215 083
1959 459 081 — 655 394 1 323 477 1 581 171 0.295 303 446
1960 470 121 — 603 851 1 332 908 1 657 104 0.246 153 937
1961 377 291 — 477 947 1 076 590 1 430 191 0.269 195 919
1962 388 985 — 515 106 1 171 146 1 464 140 0.275 125 540
1963 408 800 — 471 699 1 119 835 1 299 173 0.329 173 369
1964 437 012 — 431 795 1 060 074 1 211 498 0.333 197 658
1965 387 106 — 331 197 885 864 1 053 336 0.346 219 503
1966 353 357 — 301 796 938 337 1 063 586 0.321 232 913
1967 335 721 — 283 895 989 547 1 139 607 0.322 319 526
1968 381 770 — 251 038 990 942 1 241 848 0.319 171 449
1969 403 205 — 357 150 1 111 978 1 335 715 0.338 239 617
1970 475 077 — 359 976 1 045 550 1 332 679 0.341 179 805
1971 444 248 — 259 647 874 821 1 083 791 0.380 193 106
1972 395 166 — 235 411 776 253 979 028 0.386 142 291
1973 369 205 — 250 229 724 243 831 340 0.443 277 764
1974 368 133 — 192 139 745 624 909 778 0.402 187 287
1975 364 754 — 175 446 796 852 891 575 0.395 259 142
1976 346 253 — 146 633 925 203 948 692 0.361 367 732
1977 340 086 — 199 221 1 024 910 1 296 121 0.257 144 417
1978 329 602 — 213 709 1 130 779 1 307 062 0.271 224 301
1979 366 462 — 308 504 1 233 571 1 408 725 0.291 237 488
1980 432 237 — 375 669 1 239 277 1 511 307 0.300 141 616
1981 465 032 — 286 039 1 011 190 1 254 580 0.326 145 485
1982 380 068 — 189 146 796 336 987 942 0.329 141 313
1983 298 049 — 147 038 690 136 803 657 0.358 227 772
1984 282 022 — 156 291 763 100 915 285 0.338 143 957
1985 323 428 — 169 099 724 261 942 925 0.372 140 464
1986 364 797 — 194 155 900 518 869 564 0.439 297 879
1987 389 915 — 145 942 818 409 989 057 0.386 249 599
1988 377 554 — 154 704 783 269 976 472 0.377 176 465
1989 363 125 — 158 427 767 882 948 210 0.363 97 241
1990 335 316 — 195 078 707 759 815 738 0.389 130 198
1991 307 759 — 158 063 622 122 698 530 0.400 113 208
1992 264 834 — 143 908 512 822 565 899 0.451 159 452
1993 250 704 — 111 801 494 202 584 908 0.346 129 531
1994 178 138 — 146 713 515 480 567 871 0.302 80 796
1995 168 592 — 167 999 542 478 565 029 0.313 141 783
1996 180 701 — 154 790 600 967 678 451 0.288 165 858
1997 203 112 — 189 133 656 613 795 756 0.289 92 062
1998 243 987 — 198 850 656 326 737 973 0.345 155 615
1999 260 147 — 175 865 597 872 727 691 0.335 75 982
2000 235 092 — 162 629 563 778 589 922 0.400 167 229
2001 236 702 — 158 097 566 140 663 217 0.330 155 076
2002 209 544 — 188 177 615 779 712 875 0.292 157 738
2003 207 246 — 185 822 652 106 741 151 0.299 180 494
2004 228 342 — 192 502 661 275 810 918 0.270 84 982
2005 213 867 — 222 850 623 287 728 518 0.278 154 854
2006 197 202 — 216 942 603 090 692 337 0.260 132 236
2007 171 646 — 203 591 575 549 668 735 0.233 95 020
2008 147 676 — 254 796 587 056 673 016 0.255 130 966
2009 183 320 — 235 989 617 433 747 266 0.233 117 018
2010 170 025 — 267 129 665 566 795 951 0.215 125 591
2011 172 218 — 326 630 795 791 842 886 0.223 165 032
2012 196 171 — 362 058 895 484 962 694 0.223 175 230
2013 223 582 — 386 545 950 914 1 084 928 0.205 124 827
2014 222 021 — 353 606 913 287 1 091 620 0.208 173 857
2015 230 165 — 459 866 1 026 359 1 172 212 0.208 147 841
2016 251 219 — 403 571 994 077 1 226 339 0.201 99 566
2017 243 945 — 532 327 1 078 921 1 154 596 0.225 153 500
2018 267 221 — 522 334 1 044 172 1 198 198 0.221 154 015
2019 263 025 — 466 865 984 204 1 126 977 0.238 119 060
2020 270 302 — 411 336 958 569 1 018 844 0.262 145 557
2021 265 740 — 410 383 966 420 1 125 663 0.222 133 637
2022 242 208 — 423 614 942 477 1 107 037 0.204 173 334
2023 217 847 — 404 546 885 533 1 156 803 0.190 134 292
2024 220 340 — 378 080 816 798 1 067 887 0.205 101 582
2025 218 683 — 367 679 783 179 1 050 402 0.198 115 029
2026 202 367 201.674 377 277 736 796 997 633 — 132 259
2027 201 397 201.016 377 344 — 1 001 786 — 133 469
2028 — 201.107 369 437 — 1 005 989 — 115 513

Management

History

The Ministry of Industries is responsible for the management of Icelandic fisheries and implementation of relevant legislation. Cod was incorporated into the Individual Transferable Quota (ITQ) system in 1984. During the early years of the Total Allowable Catch (TAC) system, effort management was also implemented, partly to address concerns from stakeholders who felt they had received an unfair share of the quota. This “additional effort” management system resulted in catches exceeding the TAC by 20–30% in the initial years of the ITQ system.

In 1990, legislation was amended to eliminate effort management, except for the smallest coastal fleet, which remained under a fishing days regime. At the same time, many restrictions on quota transferability were lifted, and the fishing year was redefined to run from 1 September to 31 August. These changes took effect on 1 September 1991. In the early 1990s, scientific advice from the Marine Research Institute (MRI) was based on reducing fishing mortality (F) by 40%. However, during this period, TACs exceeded scientific advice, and catches exceeded TACs.

The cod stock declined sharply in the early 1990s due to a combination of low recruitment and high fishing mortality. Recognizing the need for stricter fisheries control, a group of fisheries scientists developed a Harvest Control Rule (HCR), which was adopted for the 1995/96 fishing year. This led to a significant reduction in fishing mortality.

Since the introduction of the HCR, TACs have been set according to the rule. However, catches have exceeded TACs by an average of approximately 5% in recent years (Figure 34). The primary reason for this overage is that catches from vessels operating under the effort control system have exceeded predictions. These predicted catches are deducted from the TAC calculated under the HCR before allocating the remaining quota to Icelandic vessels.

The TAC system does not account for catches taken by Norway and the Faroe Islands under bilateral agreements. Although the size of these catches is known in advance, they were not historically considered in the Ministry’s TAC allocation to Icelandic vessels.

There is no minimum landing size for cod in ICES Division 5.a. However, economic penalties are imposed on landings valued below a minimum size threshold to discourage such practices. Iceland, Norway, and the Faroe Islands also maintain bilateral agreements governing fishing access to restricted areas within Iceland’s EEZ. Under these agreements, Faroese vessels are permitted to catch up to 5,600 tonnes of demersal fish species in Icelandic waters, including a maximum of 1,200 tonnes of cod.

Catches from Marine and Freshwater Research Institute surveys are outside vessel quotas; this catch has typically accounted for approximately 0.5 to 1.5% of the total cod catch. Other catches not included in vessel quotas (so-called VS-catch) have increased in recent years, rising from less than 0.5% to over 1.5% in 2024/2025 (Figure 36).

Figure 34: Cod in Division 5.a. Comparison of the realised catches and the set TAC for the fishing operations in Icelandic waters.
Figure 35: Cod in Division 5.a. An overview of the net transfers of quota between years and species transformations in the fishery in 5a.
Figure 36: Cod. Overview of landings outside vessel quotas. The upper figure shows total landings classified as VS-catch and landings from surveys conducted by the Marine and Freshwater Research Institute. The lower figure illustrates the proportion of these catches relative to the total cod catch.

Harvest control rule

The TAC for the next fishing year (starting 1 September in the assessment year and ending 31 August of the following year) is based on a multiplier of 0.20 applied to the reference biomass of fish aged four years and older in the assessment year (\(B_{4+,y}\)). A stabiliser is then applied by averaging this result with the previous year’s TAC to determine the TAC for the next fishing year:

\[ \mathrm{TAC}_{y+1} = \frac{0.20 \cdot B_{4+,y} + \mathrm{TAC}_y}{2} \]

If the spawning stock biomass (SSB) is below the trigger value of 220,000 tonnes, the stabiliser is not applied. Instead, the harvest rate is scaled linearly according to the ratio of SSB to the trigger value:

\[ \mathrm{TAC}_{y/y+1} = 0.20 \cdot B_{4+,y} \cdot \frac{\mathrm{SSB}_y}{220{,}000} \]

Information regarding management strategies and harvest control rules can be found on the Government of Iceland webpage here.

A system of catch-quota balancing allowances is in place that permits quota transfers between years and some species transformations, as illustrated in Figure 35. Transfers into cod from other species are not allowed. Net quota transfers out of cod to other species have remained relatively low in recent years (Figure 35, upper panel). Transfers of unused cod quota between fishing years typically range from 0–7%.

The harvest control rule (HCR) has undergone several amendments over time. The most recent significant change occurred in 2007, when the harvest rate multiplier used to determine TAC was reduced from 0.25 to 0.20. The current HCR also includes a catch stabiliser: when SSB in the assessment year is estimated to exceed 220 thousand tonnes, the rule applies the averaging procedure as shown above.

The TAC set for the current fishing year (2025/2026), based on last year’s assessment, was 203822.

Following the 2021 benchmark, the reference biomass used in advice was estimated to be approximately 20% lower in recent years than under the previous framework. This has contributed to slightly higher realized harvest rates than intended, although these remain within the expected range of the HCR simulations. During the benchmark, reference points and the definition of harvest rate were also revised.

Management considerations

Both spring and autumn survey indices are on par with values closer to 2010. The most recent catch weights (2025) have increased slightly. However, stock weights remain low for most year classes, and both catch and stock weights have been below the long-term average for the past three years, especially for year classes composing the fishable stock. Unexpectedly low weights at age in the catch will result in higher fishing mortality. In addition, reduced energy reserves and lower prey availability could lead to increased natural mortality. Together, these factors increase the risk of stock size declining in the near future.

Despite this, commercial catch data and surveys indicate that cod in Division 5.a is currently in good condition. This is supported by the stock assessment and the most recent HCR evaluation (ICES 2021b). While the stock is presently in a strong state, the highly variable recruitment observed over the past decade suggests future fluctuations in stock size are likely. The assessment model has a tendency to underestimate catches in the most recent 5 years, and may therefore also slightly underestimate harvest rates, but this discrepancy is expected to be minor (for example, realized harvest rate in 2025 may be closer to 0.21 rather than 0.198).

Current recruitment estimates for the 2020–2022 year classes remain below the decade average. The 2023 year class is estimated closer to average, but the earliest view of the the two youngest year classes (age 1 & 2 indices in the surveys, year classes 2024–2025) do not show any marked increase in survey index values compared to the previous 5 years. As these low recruitment years occur consecutively, a decline in reference biomass can be expected in the coming years unless stronger recruitment is observed. However, because the HCR includes a cap on changes in TAC, the impact of this decline will be moderated in future advice.

Ecosystem considerations

Stock and catch weights-at-ages have been lower than the long-term average for most ages over the past three years, especially in age classes that currently dominate the reference biomass. As capelin is known to be a major prey source for cod in Icelandic waters (Pálsson and Björnsson (2011)) and capelin stock levels have been linked to cod growth (Frater et al. (2019)), the reduction in cod weights is likely linked to low levels of capelin (ICES stock cap.27.2a514) in Icelandic and Faroese waters, East Greenland, and the Jan Mayen area in recent years.

In addition, recent and historical patterns of common cohort strength shared between this stock and the East Greenland–Iceland offshore spawning cod stock (cod.21.27.1.14) suggest linkages in productivity and periodic migrations. These linkages have not been quantified but may affect assumptions of stock boundaries, stock productivity, and sustainable fishing rates.

References

Björnsson, Björn, Jón Sólmundsson, and Pamela J Woods. 2022. “Natural Mortality in Exploited Fish Stocks: Annual Variation Estimated with Data from Trawl Surveys.” ICES Journal of Marine Science 79 (5): 1569–82.
Björnsson, Höskuldur, Einar Hjörleifsson, and Bjarki ór Elvarsson. 2019. “Muppet: Program for Simulating Harvest Control Rules.” Reykjavik: Marine; Freshwater Researh Institute. http://www.github.com/hoski/Muppet-HCR.
Frater, Paul N, Birgir Hrafnkelsson, Bjarki Th Elvarsson, and Gunnar Stefansson. 2019. “Drivers of Growth for Atlantic Cod (Gadus Morhua l.) in Icelandic Waters–a Bayesian Approach to Determine Spatiotemporal Variation and Its Causes.” Journal of Fish Biology 95 (2): 401–10.
ICES. 2021a. “Stock Annex: Cod (Gadus morhua) in Division 5.a (Iceland grounds).” International Council for the Exploration of the Seas; ICES publishing. https://doi.org/https://doi.org/10.17895/ices.pub.18622199.
———. 2021b. “Workshop on the Re-Evaluation of Management Plan for the Icelandic Cod Stock (WKICECOD), ICES Scientific Reports. 3:30.” International Council for the Exploration of the Seas; ICES publishing. https://doi.org/https://doi.org/10.17895/ices.pub.7987.
Jónsdóttir, Ingibjörg G, Jón Sólmundsson, Peter J Wright, William Butler, and Pamela Woods. 2025. “Key Drivers and Spatio-Temporal Variation in the Reproductive Potential of Icelandic Cod.” ICES Journal of Marine Science 82 (7): fsaf128.
MRI. 2016. “Mælingar á brottkasti þorsks og ýsu (e. Measurments of discards of Cod and Haddock), 2014–2016, Reykjavik, Iceland.” Vol. 3. Marine; Freshwater Research Institute, Iceland; Marine Research Institute, Iceland. https://www.hafogvatn.is/static/research/files/fjolrit-183pdf.
Pálsson, Ólafur K, and Höskuldur Björnsson. 2011. “Long-Term Changes in Trophic Patterns of Iceland Cod and Linkages to Main Prey Stock Sizes.” ICES Journal of Marine Science: Journal Du Conseil 68 (7): 1488–99.