HADDOCK

Melanogrammus aeglefinus


Assessment report
Published by

Marine and Freshwater Research Institute, Iceland

Published

6 June 2025

Key signals

  • Survey biomass steadily increased from 2011, peaking sharply in 2023–2025 at levels similar to the peak observed in 2003–2006.

  • High recruitment from 2020–2022 is the primary driver behind the current biomass peak. However, recruitment in 2023 and 2024 has fallen below the decade’s average, while early indicators for 2025 suggest recruitment near this average. Consequently, it is likely that haddock biomass will decline in the near future.

  • Length distributions have remained stable over the past decade, reflecting consistent periodic recruitment and a broad range of sizes currently present in the stock.

  • Current biomass estimates from the stock assessment are the highest recorded since 1979, though these estimates carry considerable uncertainty.

  • Harvest rates have generally fluctuated around the target harvest rate set over the last decade, with no major deviations.

Stock description and management units

Haddock (Melanogrammus aeglefinus) is abundant in the coastal waters around Iceland and is mostly limited to the Icelandic continental shelf. Haddock is predominantly distributed around Iceland’s western and southern coasts, typically in depths between 10 and 200 meters. Historically, spawning activity has been restricted to southern waters. Recently, an increasing proportion of the fishable stock has been observed off the northern coast compared to previous decades.

Fishery

The haddock fishery in ICES area 5a has seen minimal structural changes recently, although the number of vessels responsible for 95% of the catch has steadily decreased (Figure 1 and Table 1). Approximately 250 longliners, 60 trawlers, and 40 demersal seine boats report catches annually. Historically, trawlers have dominated the catches, currently accounting for around 60%, while catches from longliners have increased significantly since the mid-1990s (Figure 2). Demersal seine catches have remained stable at about 15%, and contributions from other vessel types are minimal(Figure 2). Main fishing grounds are in the southern, southwestern, and western regions, with recent years showing increased catches from northern and northeastern waters (Figure 4 and Figure 5).

Figure 1: Haddock in 5a. 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.
Figure 2: Haddock in 5a. Landings in tons and percent of total by gear and year
Table 1: Haddock in 5a. Number of Icelandic vessels landing haddock, and all landed catch divided by gear type.
Year Nr. Other Nr. Long Line Nr. Danish Seine Nr. Bottom Trawl Other Long Line Danish Seine Bottom Trawl Total catch
2000 504 479 117 164 1 740 13 089 3 101 23 300 41 230
2001 631 447 91 146 2 050 11 982 3 036 22 034 39 102
2002 548 417 91 144 1 990 13 638 3 596 30 377 49 601
2003 550 435 96 136 1 664 17 284 4 804 36 239 59 991
2004 656 449 95 131 1 787 23 198 8 095 50 722 83 802
2005 488 449 90 126 1 573 30 767 10 493 53 046 95 879
2006 416 436 93 116 1 217 36 237 12 709 45 968 96 131
2007 345 407 94 109 1 080 37 199 12 869 57 033 108 181
2008 311 362 91 102 944 33 051 16 457 51 228 101 680
2009 448 335 81 98 608 26 571 15 182 39 078 81 439
2010 623 279 67 94 475 23 916 10 138 29 341 63 870
2011 630 278 54 95 473 21 175 6 866 20 718 49 232
2012 699 289 56 98 473 18 722 6 048 20 469 45 712
2013 702 282 65 95 398 19 197 4 955 18 829 43 379
2014 654 283 47 84 329 15 598 3 776 13 438 33 141
2015 607 257 50 83 360 16 432 4 327 17 337 38 456
2016 580 237 53 82 321 14 927 4 456 17 045 36 749
2017 531 210 53 80 343 14 447 4 539 16 456 35 785
2018 494 194 58 71 336 15 190 5 585 26 639 47 750
2019 493 183 43 69 302 14 650 6 237 35 947 57 136
2020 536 149 42 73 278 16 189 5 079 32 005 53 551
2021 532 142 46 82 264 14 541 5 338 35 961 56 104
2022 513 115 57 73 243 13 830 3 929 39 003 57 005
2023 607 97 60 76 304 17 589 6 599 44 869 69 361
2024 594 89 37 79 265 16 817 8 757 57 706 83 545
Figure 3: Haddock in 5a. Depth distribution of haddock catches from bottom trawls, longlines, trawls and demersal seine from Icelandic logbooks
Figure 4: Haddock in 5a. Changes in spatial distribution of haddock catches as recorded in Icelandic logbooks.
Figure 5: Haddock in 5a. Spatial distribution of catches by all gears for selected years.

Landing trends

Landings of haddock in ICES area 5.a in 2024 totaled 85177 tonnes (Figure 6). This represents a significant decrease from the high levels of approximately 100,000 tonnes recorded between 2005 and 2008, returning to levels somewhat lower than observed between 1975 and the early 2000s. Foreign vessel landings have significantly declined following the expansion of the Icelandic Exclusive Economic Zone (EEZ), with Faroese vessels now accounting for the majority of foreign catches and which in 2024 was 1442 tonnes.

Figure 6: Haddock in 5a. Recorded landings since 1905.

Data available

Sampling from commercial catches is generally comprehensive, covering the main gears (demersal seines, longlines, and trawls) and adequately representing the spatial and seasonal distribution of catches (Figure 7 and Figure 8).

Figure 7: Haddock in 5a. 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 8: Haddock in 5a. Fishing grounds last year as reported in logbooks (contours) and positions of samples taken from landings (crosses) by main gear types.

Landings and discards

Historical landings data come from various databases.

Historical landings data are sourced from various databases such as ICES STATLAN database, Directorate of Fisheries and the Icelandic Coast Guard.

Icelandic law prohibits discarding, and discard rates since 2001 have been low, generally below 3% of the total annual landings, both in weight and numbers (Figure 9, also see MRI (2016) for further details). Fisheries management regulations effectively discourage discarding through quota flexibility and quota conversion measures. In addition to prevent high grading and quota mismatch the fisheries are allowed to land fish that will not be accounted for in the allotted quota, provided that the proceedings when the landed catch is sold will go to the Fisheries Project Fund (Verkefnasjóður sjávarútvegsins).

Figure 9: Haddock in 5a. Estimates of annual discards by gear (point estimate and 95% confidence interval). No estimates are available since 2018.

Length compositions

Commercial catches primarily consist of haddock ranging from 40 to 70 cm, a range that has remained stable in recent years (Figure 10). Gillnet fisheries tend to target slightly larger individuals, and the modes of the length distributions vary more markedly depending on the presence of larger haddock.

Most length measurements are derived from the three main fleet segments: trawl, longline, and demersal seine fisheries (Table 2). The number of length samples collected by gear type has fluctuated in recent years, reflecting shifts in fleet composition.

Figure 10: Haddock in 5a. Commercial length distributions by gear and year
Table 2: Haddock in 5a. Number of samples and length measurements from landed catch.
Year
Bottom Trawl
Danish Seine
Long Line
Number of samples Number of lengths Number of samples Number of lengths Number of samples Number of lengths
2000 344 66 143 21 3 114 88 14 393
2001 359 71 914 26 4 098 168 30 110
2002 467 85 869 47 7 644 212 32 425
2003 422 71 509 75 7 094 210 31 239
2004 503 82 474 75 10 416 252 35 405
2005 514 94 529 102 14 880 375 53 472
2006 500 74 627 241 29 862 747 75 392
2007 837 102 155 515 34 922 531 87 737
2008 813 83 284 389 29 477 572 88 920
2009 630 56 466 349 35 176 406 63 817
2010 470 59 477 265 19 727 344 56 681
2011 357 53 462 204 8 494 237 43 200
2012 349 41 424 191 10 270 306 60 842
2013 267 34 357 92 2 597 237 43 132
2014 155 13 731 51 3 157 217 37 035
2015 187 26 101 92 2 816 222 41 594
2016 163 21 500 132 2 540 202 37 492
2017 200 23 387 151 6 417 232 42 360
2018 134 21 780 94 5 611 231 35 621
2019 295 50 698 42 3 266 187 25 692
2020 109 17 640 15 1 552 64 8 929
2021 139 22 264 20 2 112 38 4 669
2022 124 18 937 16 1 942 34 3 941
2023 129 23 280 35 1 947 28 3 382
2024 255 51 257 30 4 050 52 6 510

Age compositions

An overview of the sampled otoliths is provided in Table 3. The catch in numbers-at-age is illustrated in Figure 11. In 2024, the catch was primarily composed of the 2014 to 2017 year classes. In recent years, the number of year classes contributing to the catch has increased, reflecting a period of low fishing mortality. Notably, the oldest year class contributing more than 1% to the total catch was 11 years old (Figure 12).

Table 3: Haddock in 5a. Number of samples and otoliths collected from landed catch.
Year
Bottom Trawl
Danish Seine
Long Line
Number of samples Number of otoliths Number of samples Number of otoliths Number of samples Number of otoliths
1938 0 0 0 0 2 105
1939 11 192 0 0 42 101
1940 0 0 3 0 0 0
1941 6 646 1 51 7 150
1942 4 747 10 746 3 157
1943 11 1 099 3 298 22 1 282
1944 9 906 1 25 12 1 197
1945 10 899 8 609 15 1 511
1946 0 0 0 0 7 466
1947 0 0 0 0 1 4
1957 1 200 0 0 0 0
1958 0 0 0 0 3 198
1959 0 0 0 0 2 0
1960 0 0 2 200 1 0
1961 0 0 3 0 0 0
1963 0 0 9 699 0 0
1964 0 0 11 1 197 0 0
1965 1 100 14 1 180 0 0
1966 0 0 8 899 0 0
1967 0 0 7 600 0 0
1968 0 0 0 0 4 300
1969 0 0 2 61 10 525
1970 5 99 0 0 8 400
1971 0 0 0 0 5 398
1972 7 499 1 112 20 1 295
1973 1 0 0 0 23 1 101
1974 10 501 4 200 33 1 562
1975 5 312 2 0 15 825
1976 36 299 6 0 7 301
1977 38 406 3 100 28 799
1978 80 4 224 1 0 32 1 249
1979 98 5 823 6 52 38 2 615
1980 94 1 599 4 0 22 800
1981 40 1 201 16 0 12 600
1982 78 1 803 0 0 16 700
1983 79 1 549 1 0 21 993
1984 32 598 4 100 9 500
1985 29 799 4 0 15 900
1986 38 1 651 4 131 9 500
1987 101 1 596 10 0 21 701
1988 159 3 335 22 0 25 406
1989 146 1 615 42 503 28 755
1990 139 2 278 40 0 34 1 374
1991 124 2 091 28 99 28 1 195
1992 123 1 933 6 100 25 801
1993 213 3 617 16 399 28 1 394
1994 261 4 297 8 300 58 1 397
1995 187 4 588 11 800 26 1 799
1996 169 4 497 15 799 20 1 500
1997 195 6 755 19 900 18 1 500
1998 287 8 333 19 734 30 2 395
1999 406 7 156 21 900 52 2 300
2000 344 6 773 21 800 88 2 848
2001 359 5 208 26 359 168 2 755
2002 467 6 510 47 750 212 2 848
2003 422 7 237 75 878 210 3 499
2004 503 6 786 75 698 252 2 855
2005 514 6 478 102 823 375 3 520
2006 500 6 447 241 1 219 747 4 806
2007 837 6 602 515 1 969 531 4 451
2008 813 7 637 389 2 163 572 4 464
2009 630 5 449 349 1 822 406 2 800
2010 470 5 458 265 1 473 344 3 199
2011 357 3 522 204 1 140 237 2 675
2012 349 4 448 191 1 436 306 3 204
2013 267 3 039 92 750 237 2 751
2014 155 1 421 51 329 217 1 550
2015 187 1 924 92 324 222 1 151
2016 163 1 769 132 440 202 975
2017 200 1 363 151 337 232 945
2018 134 1 385 94 291 231 845
2019 295 1 740 42 362 187 925
2020 109 1 322 15 276 64 625
2021 139 1 820 20 300 38 775
2022 124 1 100 16 120 34 265
2023 129 1 462 35 234 28 440
2024 255 2 178 30 300 52 700
Figure 11: Haddock in 5a. 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. Note different scales on y-axis
Figure 12: Haddock in 5a. Catch at age from the commercial fishery in Iceland waters. Biomass caught by year and age, bars are colored by cohort.

Weight at age in the catch

Mean weight-at-age in the catch is shown in Figure 13. The weights of older year classes have increased in recent years, following a period of low values when the stock was large between 2005 and 2009. The increase in mean weight is particularly evident for younger haddock from the small 2008–2013 cohorts, contributing to an above-average mean weight among older fish. Although the mean weight of younger year classes in the catch has declined somewhat, it remains above the long-term average.

Figure 13: Haddock in 5a. Mean weight at age in the catch from the commercial fishery in Icelandic waters. Bars are coloured by cohort.

Natural mortality

No information is available on natural mortality. For assessment and advisory purpose, natural mortality is assumed to be 0.2 for all age groups.

Catch, effort and research vessel data

Catch per unit of effort from commercial fisheries

Catch-per-unit-effort (CPUE) from hauls where haddock comprise more than 50% of the catch show a steady increase in CPUE since 1990 across the main gear types (Figure 14). CPUE levels from bottom trawls and demersal seine are among the highest recorded in the time series, whereas those from longlines remain relatively low. This trend aligns with fishers’ perception that haddock are easy to catch. However, this pattern differs from that observed in surveys and stock assessments, which show less of an increase after 2000 and a more pronounced decline in recent years.

It is important to note that these differences may partly reflect changes in the size composition of the stock. The biomass of haddock ≥60 cm is currently at the highest observed level in the time series, while total biomass is near its long-term average. This suggests that CPUE trends may be more reflective of the abundance of larger individuals rather than overall stock size.

Regional differences in CPUE are also evident. In the area north of Iceland, CPUE has shown a continuous increase, whereas in southern regions it more closely mirrors the biomass trends observed in the spring survey. Bycatch is minimal, as haddock are typically targeted in species-specific catch compositions.

CPUE could not be estimated for 2022 due to the unavailability of effort data at the time of assessment.

Figure 14: Haddock in 5a. 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 haddock and solid lines on all records where haddock 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. Effort data is not available for 2022.

Icelandic survey data

Information on haddock abundance and biological parameters in Division 5.a is available from two surveys: the Icelandic spring groundfish survey and the Icelandic autumn groundfish survey. The spring survey has been conducted annually since 1985 and covers the core distribution area of the haddock fishery. The autumn survey, initiated in 1996 and expanded in 2000 to include deeper water stations, provides supplementary insight into stock development. Both surveys were originally designed to monitor the Icelandic cod stock but have proven effective in tracking the haddock stock, including juvenile abundance and fishable biomass. A full autumn survey could not be carried out in 2011. Detailed survey methodologies are described in the Stock Annex.

Figure 15 presents a recruitment index (abundance <25 cm) alongside biomass indices for total biomass, biomass >45 cm, and biomass >60 cm. Spatial shifts in biomass distribution observed in the spring survey are shown in Figure 16, indicating an increasing proportion of biomass in the northern regions (NW and NE). Length distributions from the surveys are displayed in Figure 18, and spatial distribution of survey stations is shown in Figure 17.

Both surveys show a substantial increase in total biomass between 2002 and 2005, followed by a marked decline from 2007 to 2010. While overall trends are similar, the autumn survey tends to show less contrast between periods of high and low biomass. A notable discrepancy occurred in 2015, when the autumn survey estimated substantially lower biomass than surrounding years. Differences between the surveys are more pronounced in the >60 cm biomass index, which has reached its highest recorded level in recent years according to both surveys. A sharp increase in total survey biomass was observed in autumn 2022 and spring 2023.

Age-disaggregated indices from the spring survey are shown in Figure 19. Consistent with the increase in >60 cm biomass, the index for age 11+ is now higher than previously recorded. This is likely due to reduced fishing mortality following the implementation of the management plan for haddock in 5.a. Despite a recent period of low recruitment, the biomass for other age groups is currently near the geometric mean in both surveys.

Figure 15: Haddock in 5a. Indices (total biomass, biomass> 45 cm, biomass> 60 cm and abundance <25 cm) in the Spring Survey (March) 1985 and onwards (line shaded area) and the autumn survey (point ranges).
Figure 16: Haddock in 5a. Changes in geographical distribution of the survey biomass.
Figure 17: Haddock in 5a. Location of haddock in the most recent March (SMB) and the Autumn (SMH) surveys, bubble sizes are relative to catch sizes, and crosses indicate stations where no haddock was observed.
Figure 18: Haddock in 5a. Length disaggregated abundance indices from the March survey 1985 and onwards.
Figure 19: Haddock in 5a. Age disaggregated indices in the Spring Survey (left) and the autumn survey (rights). Bars indicated the deviation from the log mean index, fill colors indicate cohorts. Note different scales on y-axes.

Stock weight at age

Mean weight-at-age in the catch is shown in Figure 13. Stock weights are derived from the spring groundfish survey and are also used as mean weight-at-age in the estimation of spawning stock biomass. Both stock and catch weights for the older year classes have increased in recent years, following a period of notably low values when the stock was large between 2005 and 2009.

The increase in mean weight-at-age is particularly evident among younger haddock from the small 2008–2013 cohorts, contributing to above-average mean weights in the older age groups. Although the mean weight of the younger year classes has declined somewhat in recent years, it remains above the long-term average.

Figure 20: Haddock in 5a. Stock weights from the March survey in Icelandic waters. Bars are coloured by cohort.

Stock maturity at age

Maturity-at-age data, shown in Figure 21, are derived from the spring survey. In recent years, the maturity-at-age of the youngest age groups has declined, likely reflecting a northward shift in distribution. Maturity-at-size has also decreased, which is most plausibly explained by a larger proportion of these age groups occurring north of Iceland – an area where the proportion of mature individuals has historically been low.

Figure 21: Haddock in division 5a. Maturity at age in the survey. Bars are coloured by cohort. The values are used to calculate the spawning stock.

Data analyses

Analytical assessment

This stock was last benchmarked in 2025 as part of a harvest control rule evaluation (ICES (2025)). The assessment framework was updated to a state-space statistical catch-at-age model (SAM; Nielsen and Berg (2014)). The model spans from 1979 onward and tracks ages 1 to 12, with age 12 defined as a plus group. Natural mortality is assumed to be 0.2 for all age groups, and selectivity-at-age is allowed to vary over time.

Given that haddock are known to spawn between April and the end of May, the ratio of fishing and natural mortality before spawning was set at 0.4 and 0.3, respectively.

Data used by the assessment

The assessment is based on four primary data sources, as described above: the Icelandic spring and autumn groundfish surveys, commercial sampling, and landings data. Commercial data are used to construct catch-at-age matrices, which enter the model likelihood alongside survey-at-age data from both surveys. Stock and catch weights-at-age are derived from the spring survey and commercial catches, respectively. Maturity-at-age data are also obtained from the spring survey.

For years prior to 1985 — before the initiation of the spring survey — stock weights and maturity-at-age were assumed to be constant at their 1985 values. A detailed description of the data preparation for model tuning and input is provided in the Stock Annex (ICES (2019a)).

Diagnostics

Model fit diagnostics are shown in Figure 22 and Figure 23, illustrating residuals for observation and process error, respectively. No concerning patterns are evident in either set of residuals. The overall model fit is further evaluated in Figure 24, which compares observed and predicted survey biomass.

Historically, biomass estimates from the autumn survey have aligned more closely with model predictions than those from the spring survey. The spring survey tends to show a greater contrast in observed biomass than is reflected in the model output. When comparing biomass levels before and after the mid-2000s peak, the autumn survey suggests higher post-peak biomass, whereas the spring survey indicates similar levels. The assessment model appears to represent a compromise between the two survey indices.

Figure 22: Haddock in division 5a. Residualsfrom the model fit to survey and catch data based on the both the surveys (observation error). Red circles indicate negative residuals (observed < modelled), while blue postive. Residuals are proportional to the area of the circles.
Figure 23: Haddock in division 5a. Residuals from the model fit to survey and catch data based on the both the surveys (process error). Red circles indicate negative residuals (observed < modelled), while blue postive. Residuals are proportional to the area of the circles.
Figure 24: Haddock in division 5a. Aggregated model fit to the total biomass indices. Note that residual correlation is estimated (see text for further details).

Model results

The assessment results indicate that the stock declined between 2008 and 2011, as large year classes were replaced by smaller ones (Figure 25). From 2011 to 2017, the stock stabilized due to reduced fishing mortality, and since 2017, stock biomass has increased rapidly, driven by the recruitment of strong year classes into the fishery. The harvest rate is currently estimated to be above the target set by the implemented harvest control rule (HCR), although it remains low by historical standards. The baseline assessment suggests that the stock is at a high level and is expected to remain so in the near future. However, a gradual decline is anticipated as the strong 2019 cohort—currently dominating the catch—is progressively fished down.

The stock–recruitment relationship (Figure 26) indicates episodic high recruitment events that can elevate stock levels, as seen at present. Apart from these peaks, recruitment appears steady, with no evidence of impairment. The retrospective analysis (Figure 28) shows an upward revision in recent years, attributed to strong incoming recruitment into the fishable biomass, and the assessment is considered stable as a result.

Some differences have been observed in recent years between model runs depending on which tuning series — spring and/or autumn surveys — are included. However, these differences are currently mostly within the bounds of model uncertainty (Figure 27), though this has not always been the case. When the model is fitted using catch data only, the trend in reference biomass diverges from that of the baseline assessment. Notably, last year’s catch-only assessment suggested a more rapid increase in biomass, highlighting the greater uncertainty in stock status estimates when survey data are excluded.

Estimated selectivity-at-age, shown in Figure 29, displays substantial temporal variation. This is consistent with density-dependent growth observed in Icelandic haddock, which affects selectivity patterns over time.

Figure 25: Haddock in division 5a. Summary from assessment. Dashed vertical line indicates the assessment year and yellow shaded region the uncertainty as estimated by the model. Dashed horizontal lines indicate the target harvest rate and MGT Btrigger within the harvest control rule. The black horizontal line indicates Blim.
Figure 26: Haddock in 5a. Spawning stock size and recruitment.
Figure 27: Haddock in 5a. Comparision of assessment results where either the spring survey or the autumn survey is omitted from the estimation.
Figure 28: Haddock in division 5a. Analytical retrospective analysis of the assessment of haddock with a 5 year peel.
Figure 29: Haddock in 5a. Estimated selection at age.

Short term projections

Following the revision of the harvest control rule (HCR) in 2025 (see Management section), short-term projections of stock weights are no longer required for generating catch advice. This is because the harvest rate is now applied to the assessment-year estimate of the reference biomass (2025), defined as haddock ≥45 cm, rather than to the projected biomass for the advisory year (2026).

Nevertheless, short-term projections remain valuable for monitoring the expected development of spawning stock biomass (SSB) over the advisory year and into the subsequent year under the applied HCR. These projections are conducted by applying the HCR for both the advisory year and the following year, using stock and catch weights averaged over the past five years, and recruitment fixed at the mean over the past ten years. A detailed technical description of this procedure is provided in the Stock Annex (ICES (2019a)).

Management

The Icelandic Ministry of Industries is responsible for the management and legislative implementation of Icelandic fisheries. Each fishing year (1 September–31 August), the Ministry issues regulations governing commercial fishing, including the allocation of total allowable catch (TAC) for stocks subject to catch limits. Haddock in Division 5.a has been managed by TAC since 1987. Landings have generally aligned with the advice provided by the Marine and Freshwater Research Institute (MFRI) and the TAC set by the Ministry (Figure 30).

However, since the 2001/2002 fishing year, landings have exceeded the set TAC by more than 5% in twelve fishing years. The most substantial overshoot occurred in 2020/2021, when haddock landings exceeded the advice by 33%. These implementation errors are primarily attributed to features of the management system that allow for inter-annual quota transfers and species transformations — i.e., the conversion of TAC between species.

The Icelandic TAC system does not account for catches taken by Norway and the Faroe Islands under bilateral agreements. While the levels of these foreign catches are known in advance, they have only recently been considered by the Ministry when allocating TAC to Icelandic vessels. There is no minimum landing size for haddock in 5.a. Under current agreements, Faroese vessels may fish up to 5,600 tonnes of demersal species annually in Icelandic waters, including a maximum of 1,200 tonnes of cod and 40 tonnes of Atlantic halibut.

The impact of species transformations and quota transfers is illustrated in Figure 31. During the period of high haddock biomass (2002–2007), there was a notable increase in net transfers of quota from other species to haddock. This may partly reflect changes in haddock distribution, as shown in Figure 5 — particularly in northern areas where fisheries held lower initial haddock quotas. Over the longer term, however, net quota transfers to or from haddock have averaged close to zero.

The introduction of a management plan in 2013 has significantly reduced inter-annual quota transfers. Concurrently, transfers from other species to haddock have increased — likely due to high CPUE in recent years, the ease of catching haddock, and its potential to act as a limiting factor in some mixed fisheries. Additionally, possible underestimation of haddock biomass in recent years may have contributed to increased quota transfers into the haddock fishery. These dynamics were accounted for in the management plan evaluation.

Figure 30 shows the differences between the national TAC and actual landings for haddock in 5.a. In most cases, deviations can be explained by species transformations. Notably, in the 1999/2000 and 2020/2021 fishing years, the Icelandic government adjusted the TAC mid-season. In 2020/2021, the TAC was increased by 8,000 tonnes and reduced by the same amount in the following fishing year.

The current management plan for haddock in Icelandic waters was reviewed by ICES in 2025 (ICES, 2025). Beginning with the 2025/2026 fishing year, the harvest control rule was revised as follows:

If \(SSB_{y}\geq B_{trigger}\) then: \[ TAC_{y+1} = 0.35 B_{45cm^+,y} \]

If \(SSB_{y}< B_{trigger}\) then: \[ TAC_{y+1} = 0.35 B_{45cm^+,y} SSB_{y}/B_{trigger}\]

The revised harvest control rule retains the same harvest rate and reference biomass definition as the previous HCR. However, the key change is that the harvest rate is now applied to the reference biomass estimated for the assessment year, rather than a projected biomass for the advisory year, as was done previously. As a result, short-term projections of stock weights are no longer required for generating catch advice.

Figure 30: Haddock in 5a. Comparison of the realised catches and the set TAC for the fishing operations in Icelandic waters. Note that in the 1999/2000 fishing year the government of Iceland increased TAC mid-season
Figure 31: Haddock in 5a. An overview of the net transfers of quota between years and species transformations in the fishery in 5a.

Management considerations

All available indicators from commercial catch data and scientific surveys suggest that haddock in Division 5.a is currently in good condition, a conclusion supported by the stock assessment. At WKICEMSE 2019, the harvest rate applied under the 2013–2018 harvest control rule (HCR) was deemed no longer precautionary. A harvest rate of 0.35 was found to be consistent with both the precautionary approach and the ICES MSY framework (ICES (2019b)). This rate was retained during the 2025 revision of the HCR conducted at WKICEGAD (ICES, 2025), but is now applied to the reference biomass estimated in the assessment year rather than the advisory year.

In 2025, the stock is estimated to have increased substantially. However, it is projected to begin declining in the coming years as the above-average year classes that have supported the recent increase move through and out of the fishable biomass. The analytical retrospective analysis revealed a slight negative bias in the estimated spawning stock biomass (SSB). This bias is expected to diminish in future assessments, as the low survey indices from 2020 and 2021 are removed from the retrospective peel and the stock begins its anticipated decline.

References

ICES. 2019a. “Stock Annex: Haddock (Melanogrammus aeglefinus ) in Division 5.a (Iceland grounds).” International Council for the Exploration of the Seas; ICES publishing.
———. 2019b. “Workshop on the Benchmark Assessment and Management Plan Evaluation for Icelandic Haddock and Saithe (WKICEMSE),” January. https://doi.org/10.17895/ices.pub.5091.
———. 2025. “Workshop on the benchmark assessment and management plan evaluation for Icelandic haddock and saithe (WKICEGAD). ICES Scientific Reports [in press].”
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.
Nielsen, Anders, and Casper W. Berg. 2014. “Estimation of Time-Varying Selectivity in Stock Assessments Using State-Space Models.” Fisheries Research 158: 96–101. https://doi.org/10.1016/j.fishres.2014.01.014.