SAITHE

Pollachius virens


Assessment report
Published by

Marine and Freshwater Research Institute, Iceland

Published

6 June 2025

Key signals

  • Catch has been below the TAC every year since 2013, with discards negligible (~0.1%) and only ~60% of the 2023/24 TAC taken.

  • Harvest rates remain consistently below all reference points (HRMGT, HRMSY, HRpa).

  • Spawning stock biomass (SSB) is currently above all key thresholds (Blim, Btrigger, Bpa).

  • Fishery composition is dominated by bottom-trawl effort, with minimal gillnet and other gear use; 2024 landings fell below 40 kt—the lowest annual catch since 2001.

  • Distribution has shifted northward over the past decade: in 2017–18, over 50% of saithe landings occurred northwest of Iceland.

  • TAC is set as Cy/y+1 = 0.2 × B4+, where B4+ is based on stock weights; this harvest-control rule was evaluated against the recent survey variability.

General Information

Saithe in Icelandic waters is managed as a one unit, though tagging studies have shown that in some years saithe migrates from distinct waters into Icelandic waters and vice versa. Saithe is both demersal and pelagic. They can be found all around Iceland, and most common in the warm waters south and southwest off Iceland. In the last decade the distribution has gradually become more northerly and in 2017 and 2018 more than 50% of the catches were taken northwest of Iceland. Less is known about the spawning of saithe than other gadoids in Iceland. Spawning is thought to take place in shallow water (100–200 m) off the southeast, south and west coast of Iceland. The main spawning area is considered to be south/southwest off Iceland (Selvogsbanki, Eldeyjarbanki). Spawning was believed to be earlier than for cod but observations from the gillnet survey conducted in early April show substantial spawning of saithe later than expected from earlier studies. Spawning seems to take place in February–April and the timing of spawning seems to be variable. The larvae drift clockwise around Iceland and in mid-June, juveniles can be found in many coves, bays, and harbours, at about 3–5 cm in length. At age 2, they move to deeper waters in winter.

Saithe become mature at age 4–7. According to available data, approximately 115 thousand saithe were tagged in the NE Atlantic in the 20th century, most of them in the Barents Sea with total returns just under 20 thousand (Jónsson, 1996). Around 6 thousand saithe were tagged in Icelandic waters in 1964–65, the recapture rate being 50% (Jones and Jónsson, 1971). Based on recaptures by area, approximately 1 in 500 of tagged saithe released outside Icelandic waters were recaptured in Icelandic waters, and 1 in 300 released in Icelandic waters were recaptured in distant waters (Jónsson, 1996). For comparison, cod long-term emigration rate from Icelandic waters is 1 in 2000 tagged fish (Jónsson, 1996), a rate almost an order of magnitude lower. Other evidence of saithe migrations do exist, albeit of a more circumstantial nature. Sudden changes in average length or weight at age and reciprocal fluctuation in catch numbers at age in different areas of the NE Atlantic have been interpreted as signs of migrations between saithe stocks (Reinsch, 1976; Jakobsen and Olsen, 1987; Jónsson, 1996). Since mean weight at age decreases along an approximately NW to SE to NE gradient, migration of e.g. northeast arctic saithe to Icelandic waters will, theoretically, be detectable as a reduction in size at age in the Icelandic saithe catches. Catch curves from some year classes, from different areas show some reciprocal variations. Inspection of the data based on the above indicate that the most likely years and ages for immigration are as follows: Age 10 in 1986, age 7 in 1991, age 9 in 1993 and the 1992 year class as age 7 saithe in 1999 and 8 in 2000. Currently only the migration of age 7 in 1991 is included in the assessment but it is the largest migration, estimated around 10 million individuals or 35 thousand tonnes. The other potential migrations are smaller and not significant if estimated on “normal scale”. A tagging program was conducted in Icelandic waters in 2000–2004 from which ~1750 of ~16000 tags released have been returned. The number of returns from areas other than the Icelandic EEZ has now reached 10 or around 2.5% of the recaptures outside the management area of the stock. Most were tagged at eastern localities and recaptured in Faroese waters, with a pulse of tags recovered in early 2006. Other foreign returns have come from areas west of Scotland and east of Greenland.

Fishery

The number of boats accounting for 95% of the total saithe catch has declined from 200-300 boat in 1994–2001 to around 100 boats after 2000 (Figure 1, Table 1).

In the last two decades, most of the catch was taken by bottom trawl (83% in 2010–2017, 90% in 2018–2023), with gillnet and jiggers taking the majority of the rest, 5% for each fleet (Figure 2, Table 1). The share of the gillnet fleet was larger in the past, 26% in 1987–1996 compared to 8% in 1998–2020. Reduction in the gillnet fisheries is caused by general reduction in gillnet boats that are mostly targeting cod and increased mesh size in gillnet fisheries targeting cod. The catch by foreign vessels before 1978 was nearly all taken by bottom trawl.

The reduction in the gillnet fleet was driven by boats changing from gillnets to longlines, a change driven by cod and haddock fisheries. For saithe fisheries, it is important to note that saithe is rarely caught by longliners, so the fleet has become much less directed toward saithe fishing than before. The share of longlines increased gradually from 0.8% before 2000 to 2.2% in 2013–2016 reducing to less than 1% in 2021 and 2022. The share of longline increased slightly in 2023, but the catch remained similar.

The fleet using demersal trawl can be divided in two parts, those that freeze the catch and those that land it fresh. The trend in the last decade has been an increase in the trawler fleet that lands the catch fresh. Freezing trawlers have taken large proportions of the catch of saithe and redfish but much less of cod and haddock. The main reason for this is relative price of frozen vs fresh fish for each species. Mixed fisheries issues, like avoiding redfish when catching fish to be landed fresh, can be a factor, as redfish spines damage the catch. The same vessels are catching redfish and saithe in the same area but not in the same hauls. Redfish is mainly caught during daytime and saithe during the night.

Most of the saithe is caught by bottom trawl at 100-200 m depth (Figure 3). Other gears include gillnets that catch saithe at 50-200 m depth and Danish seine and handline that catch saithe at depths less than 150 m.

The spatial distribution of the saithe fisheries changed greatly from 2002–2014 (Figure 4, Figure 5). Before 2002 most of the saithe was caught south and west of Iceland, but since 2012, 40–50% of the catch has been taken northwest of Iceland. Comparable percentages before 2002 ranged 3–8%. Similar increases can be seen for golden redfish, but redfish and saithe have for a long time been caught by the same vessels, not necessarily in the same hauls, rather as a night versus day fishery. The area where saithe is caught now has since the beginning of the 20th century been the most important cod fishing ground for trawlers.

Figure 1: Saithe. 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: Saithe. Landings in tons and percent of total by gear and year
Table 1: Saithe. Number of Icelandic vessels landing saithe, and all landed catch divided by gear type.
Year
Bottom Trawl
Gillnets
Other gears
Total
Number of boats Catch Number of boats Catch Number of boats Catch Catch
2000 157 25 936 258 4 308 90 980 31 224
2001 138 24 586 308 4 549 65 757 29 892
2002 131 35 606 281 3 311 66 942 39 859
2003 123 45 096 246 2 214 72 1 097 48 407
2004 124 55 394 250 2 254 87 1 347 58 995
2005 130 59 947 210 2 996 84 1 399 64 342
2006 124 65 698 165 3 790 81 1 448 70 936
2007 120 56 092 135 3 919 103 1 312 61 323
2008 103 59 385 129 6 199 131 1 359 66 943
2009 109 46 731 135 9 380 127 1 440 57 551
2010 107 43 903 163 4 483 142 1 166 49 552
2011 104 40 991 157 3 451 129 1 487 45 929
2012 99 41 183 166 3 664 111 1 643 46 490
2013 102 48 813 145 3 109 98 1 383 53 305
2014 96 39 294 145 2 368 78 1 037 42 699
2015 95 41 358 141 2 425 96 1 197 44 980
2016 89 43 176 130 2 521 84 921 46 618
2017 85 44 748 109 1 350 73 977 47 075
2018 79 61 507 94 1 717 84 987 64 211
2019 69 58 836 96 1 425 65 1 461 61 722
2020 79 44 141 88 2 583 59 990 47 714
2021 84 53 482 105 2 979 74 1 201 57 662
2022 79 53 760 89 2 642 82 1 476 57 878
2023 79 36 430 96 1 335 78 937 38 702
2024 79 35 123 81 940 57 552 36 615
Figure 3: Saithe. Depth distribution of saithe catches from bottom trawls, longlines, trawls and demersal seine from Icelandic logbooks
Figure 4: Saithe. Changes in spatial distribution of saithe catches as recorded in Icelandic logbooks.
Figure 5: Saithe. Spatial distribution of catches by all gears for selected years.

Landing trends

Information on landings of saithe exist since 1905 (Figure 6). From 1905–1938 most of the catch was taken by foreigners, and also from 1950–1975 when foreigners, mostly Germans, accounted for 60% of the saithe landings (Figure 6). Mean annual catch of saithe has been 65 thous. tons since 1955, 73 thous. tons before 1980 but 60 thous. tons after 1980. In the last five years, the catch by foreigners has always been less than 300 tons and 0.5%, of which nearly all the catch has been taken by Faroese vessels. In 2024, landings were 38 538 tons. It is almost 10% reduction from 2023, when landings were 42 114 tons, which was far from the set quota, 66 114 tons for 2023/2024 and 66 705 tons for 2024/2025. Landings of Icelandic saithe in 2024 are estimated to have been 38,736t (see also Figure 6).

Figure 6: Saithe. Recorded landings since 1905. Note: “Other” represents mostly German landings.

Data available

The samples used to derive catch in numbers are both taken by observers at sea and from shore samples (Figure 7, Figure 8). The trawlers that freeze the catch account for the majority of sea samples, while all shore samples are from fresh fish trawlers. In addition, relatively few fishes from sea samples are sampled for otoliths but the age-length keys are similar between sea and shore samples even though the length distributions differ. The bottom trawl sampling covers mostly covers the trend of the landings well.

Length distributions from sea and shore samples show some difference, where the shore samples show usually more of large fish.

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

Discards

Discarding is not considered to be a problem in the Icelandic saithe fisheries, with an estimated discard proportion of 0.1% (Pálsson 2005, 2008; Sigurðsson et al. 2016). Recently, the fleet does also seem to have difficulty in catching the set TAC, making discards more unlikely.

In 1999–2005, substantial fisheries of blue whiting were conducted within Icelandic and Faroese jurisdictions. From 2003–2005, bycatch of saithe in those fisheries was estimated to be 1500-4000 tons per year, less than half of that within Icelandic jurisdiction (Pálsson 2005). Since 2007, blue whiting fisheries in Icelandic jurisdiction have decreased significantly compared to 2000–2005.

Length compositions

The bulk of the length measurements is from the four segments, i.e. trawls, Danish seine, gillnets and hand lines. The number of available length measurements by gear has fluctuated in recent years in relation to the changes in the fleet composition.

Length of saithe caught by nets are in general larger compared to saithe caught by trawl (Figure 9). Length distribution of other fishing gears are similar to trawl.

Figure 9: Saithe. Commercial length distributions by gear and year

Sampling from commercial catch has been revised in recent decades, the number of samples has reduced and also the number of otoliths per sample. Sampling in 2020 was much less than in the years before, the number sea samples and number of age samples was especially low. The main explanation seems to be the COVID-19 epidemic. In 2021 the sampling was back to the level in 2017–2019 but has reduced again in 2022–2024 (Table 2).

Around 90% of the length samples are taken from trawl that accounts for ~90% of the catches.

Length distributions from bottom trawl show a tendency to catch smaller fish from 2003–2017 but again larger fish in 2018–2020. In 2020 the +110 cm group was especially abundant, but proportion of 60-69 cm fish was above average in 2022. In 2024, an increased amount of larger saithe was caught.

Table 2: Saithe. Number of samples and length measurements from landed catch.
Year
Bottom Trawl
Gillnets
Number of samples Number of length measurements Number of samples Number of length measurements
2000 146 21 359 20 2 646
2001 156 23 798 27 3 224
2002 197 30 638 17 2 722
2003 231 36 570 13 1 540
2004 245 38 768 5 588
2005 354 57 381 26 1 806
2006 383 50 122 32 3 794
2007 450 47 544 28 2 845
2008 431 43 666 34 4 039
2009 326 30 414 52 7 248
2010 362 41 688 38 5 020
2011 191 25 150 31 5 248
2012 353 34 757 13 1 833
2013 314 33 966 9 1 331
2014 306 32 654 10 1 036
2015 229 32 599 18 2 044
2016 249 36 940 14 1 382
2017 213 29 646 8 408
2018 143 25 487 6 465
2019 159 28 297 2 14
2020 57 8 182 9 631
2021 159 29 047 2 234
2022 104 15 325 6 707
2023 87 14 295 4 374
2024 86 12 133 6 383

Age compositions

Table 3 summarizes the number of samples and otoliths collected by gear type each year. Over time the number of samples in the gillnets reduced substantially, which is due to the decrease in gillnet fishing in general. In 2024, most of the catch derived from the 2014–2017 year classes (Figure 10). The number of year classes contributing to the catches has increased in recent years; the result of low fishing mortality in recent years and the last year class contributing with more than 1% of total is 11 years old (Figure 11).

Table 3: Saithe. Number of samples and otoliths collected from landed catch.
Year
Bottom Trawl
Gillnets
Number of samples Number of otoliths Number of samples Number of otoliths
2000 146 4 491 20 921
2001 156 4 646 27 1 159
2002 197 4 908 17 500
2003 231 6 462 13 451
2004 245 4 988 5 150
2005 354 5 267 26 71
2006 383 6 267 32 450
2007 450 6 464 28 359
2008 431 6 325 34 800
2009 326 4 687 52 897
2010 362 5 184 38 550
2011 191 4 775 31 299
2012 353 6 292 13 402
2013 314 3 993 9 449
2014 306 2 511 10 250
2015 229 2 426 18 375
2016 249 2 565 14 300
2017 213 1 541 8 82
2018 143 1 659 6 75
2019 159 1 270 2 0
2020 57 850 9 75
2021 159 1 581 2 50
2022 104 1 201 6 100
2023 87 925 4 20
2024 86 983 6 0
Figure 10: Saithe. 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 11: Saithe. 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

Weights of ages 4–6 and 11-14 have been low in recent years, but 7-10 are close to average weight (Figure 12). The large 2012 cohort has the lowest mean weight of all year classes, both in catches and in the survey. This is in line with density dependent growth that has been observed in this stock and can for example be seen for year classes 1984 and 2000 that are both large. Year classes 2013 and 2014 that seem to be above average have higher mean weight at age than the 2012 cohort. The long-term trend since 1980 has been a gradual decline in the mean weight of all ages. Mean weight at age in catches was close to average in 2024 was slightly below average for the older age classes, but otherwise close to the average.

Weights at age in the landings were used to compile the reference biomass (B4+) that is the basis for the catch advice. After the benchmark 2025 (ICES, 2025) it was decided to use stock weights instead of catch weights to compile SSB.

Figure 12: Saithe. 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 the natural mortality is set to 0.2 for all age groups (ICES, 2025).

Catch per unit of effort from commercial fisheries

Catch per unit of effort data from the bottom trawl fleet shows considerable variability, and has decreased considerably from its peak in 2018 (Figure 13). CPUE in the last three years is the lowest it has been since 2011. Unit effort is here hours trawled and the CPUE index for each year is the median of the CPUE for the selected hauls.

When compiling CPUE indices, deciding which hauls to base the analysis on is not straightforward. All hauls inside a particular area, all hauls with saithe recorded, or all hauls with saithe accounting for more than a defined proportion of total catch could be chosen. The larger the stat-ed fraction, the greater the variability in the CPUE index.

CPUE in the last three years is not low as compared to earlier years, especially if the index is compiled based on all hauls where saithe has been registered. The question is then if data 15 years ago are comparable to modern data, owing to technological advances. However, CPUE indices show considerable similarity to total biomass index from SMB.

Figure 13: Saithe. 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 saithe and solid lines on all records where saithe is caught. Effort data is not available for 2022. BMT = Beam Trawl.

Icelandic survey data

Saithe is among the most difficult demersal fishes to get reliable information from bottom trawl surveys. In the spring survey, which has 500–600 stations, a large proportion of the saithe is often caught in relatively few hauls and there seems to be considerable inter-annual variability in the number of these hauls.

The biomass indices from the spring survey fluctuated greatly from 1985–1995 but were consistently low from 1995–2001 (Figure 14). Since 1995 the indices have been variable but compared to the period 1985–1995 the variability seems “real” rather than noise. This difference is also seen by the estimated confidence intervals of the indices that are smaller after 1995. In 2018 the indices were the highest in the series and had tripled since 2014. Most of the increase was caused by year class 2012 that was strong in the surveys 2015–2018. The index decreased between 2018–2020. It has been variable in last six years, was lowest in 2022 but increased again in the last three years.

The high index in 1986 is mostly the result of one large haul that is scaled down to the second largest haul when compiling indices for tuning. Estimated CV from the survey is often relatively high and many relatively low values appear in the survey matrix, both for the youngest and oldest age groups. The youngest age group (age 3–4 and younger) are considered to inhabit waters shallower than the survey covers and the older age groups are reducing in numbers and could also be pelagic. The high index in 2018 came from relatively large catches in many hauls so the estimated CV was around average.

The autumn survey shows similar trend as the spring survey and the index is at high level in 2017 (2004 and 2018 are outliers due to large CV). The values before 2000 might be underestimated due to stations added in 2000 where large schools of saithe were sometimes found. Excluding these stations leads to a lower but more stable index.

The sample position of both the spring and autumn survey is shown in Figure 15.

Length distributions from the surveys are displayed in Figure 17, and spatial distribution of survey stations is shown in Figure 16.

Age-disaggregated indices from the spring and autumn survey are shown in Figure 18.

Figure 14: Saithe. 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 15: Saithe. Changes in geographical distribution of the survey biomass.
Figure 16: Saithe. Location of saithe in the most recent spring (SMB) and the autumn (SMH) surveys, bubble sizes are relative to catch sizes, and crosses indicate stations where no saithe was observed.
Figure 17: Saithe. Length disaggregated abundance indices from the spring survey (SMB), autumn survey (SMH) and the gillnet survey (SMN).
Figure 18: Saithe. Age disaggregated indices in the spring Survey (left) and the autumn survey (right). 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 for Icelandic saithe is derived from data collected during the Icelandic groundfish survey in spring (SMB), following the standard protocol used in Icelandic assessments. Fish sampled for ageing are weighed both ungutted and gutted, with liver and gonad measurements taken for mature individuals. The estimation procedure involves three main steps: first, the length–ungutted weight relationship is computed; second, this relationship is applied to the observed length distribution to obtain numbers and biomass; and third, an age–length relationship converts these values into age‐specific indices for numbers and biomass, which are then aggregated across strata. Although the non-stratified sampling of fish for ageing would yield similar results if simply averaged, this structured approach maintains consistency with historical assessments.

Mean weight-at-age in the stock is shown in Figure 19

Figure 19: Saithe. Stock weights from the spring survey. Bars are coloured by cohort.

Stock maturity at age

Maturity-at-age data are obtained from the groundfish survey in March. In our assessment, we do not use the SMSF maturity scale. Instead, for cod, haddock, and saithe, we classify maturity using a five-stage system: immature, mature, running, spent and uncertain (e.g. skip spawning).

When estimating maturity-at-age, saithe at maturity stages 2-5 is a part of spawning stock biomass, while maturity stage 1 is immature. To reduce variability in maturity-at-age, a running average of three years is used.

There are considerable differences in the identification of maturity stages between the autumn and spring surveys. For instance, while we use five maturity stages for cod, haddock, and saithe, other species such as capelin are assessed using a seven-stage maturity scale. This tailored approach allows us to better reflect species-specific biology and the nuances of different survey methodologies, ensuring that the mature fraction and skipped spawning are appropriately represented in the assessment.

Maturity at ages 4–9 has decreased in recent years and is currently below average since 1985, but above average for 7-9-year old saithe (Figure 20).

Figure 20: Saithe. Maturity at age in the spring survey. Bars are coloured by cohort. The values are used to calculate the spawning stock.

Stock Assessment

Model setup

The saithe stock assessment is based on a statistical age-structured catch-at-age model (Nielsen and Berg, 2014), where model parameters are formulated as random effects in a state-space framework. In this approach, the development of state variables (numbers-at-age and fishing mortality) follows a multivariate normal distribution. The model allows for variable natural mortality and fishing selectivity if patterns in the data indicate this. It also provides multiple options for specifying variance in the data, linking it to age or abundance of fish in the stock, and defining correlations in various ways.

Key components of the saithe stock assessment model setup are as follows:

  • Age ranges:
  • Catch: 3 to 14\(^+\)
  • Surveys: 3 to 14\(^+\)
  • F (fishing mortality) age range: 4 to 9 years
  • Natural mortality (M): 0.2 for all age groups
  • Recruitment model: Moving average of previous years
  • Data weighting: Default settings
  • Variability deviations in M: Default settings
  • Survey models: Linear relationship
  • Model start year: 1979

For more details, see ICES (2025).

Changes since the last assessment

The saithe stock assessment underwent a benchmark review in early 2025, during which the harvest control rule for the stock was also evaluated (ICES, 2025). The assessment model was changed, replacing the previously used Muppet model (Bjornsson et al., 2019) with the SAM state-space model described above.

Since 2010, the assessment has been based on age-disaggregated catch and age-disaggregated abundance indices from the spring survey (SMB). During this period, the assessment underwent benchmark reviews three times—in 2010, 2019, and 2025. At the latest benchmark, the use of data from other surveys was tested, and the results of these tests are presented in the benchmark report (ICES, 2025). The conclusion was that relying exclusively on SMB indices was optimal. Compared to the autumn survey, the SMB survey has more stations (lower coefficient of variation) and a longer time series.

During the model update, input data, including age-structured catch data, were reviewed and revised. Previously, age-structured catch was determined based on length-weight relationships using gutted weights, converting these to ungutted weights using gutted-to-whole conversion factors. It was instead decided to use direct ungutted weights by length to harmonize data processing with other stocks. These changes primarily impact portions of the stock rarely seen in catches, increasing estimated weights for older fish and decreasing those for younger ones.

Data on maturity-at-age from spring surveys were also revised, reducing the extent of data smoothing. Maturity data now better reflect observed fluctuations in measured maturity-at-age. To mitigate variability in stock weights, mean weights for saithe aged 9 and older were set as a running average over the three preceding years.

Additionally, the processing method was adjusted such that saithe aged 14 and older in catches and survey indices are now grouped into a plus group.

Assesment diagnostics

Model diagnostics are shown in Figure 21 and Figure 24, revealing no discernible patterns in the model residuals, aside from somewhat increased variance of residuals in the initial years. When examining the model fit for the total saithe index (see Figure 25, which shows predicted indices compared to observed values), the model successfully captures the overall trend of the SMB index but struggles to accurately track the largest fluctuations at the beginning of the time series, as well as the recent peak in 2019. It is reasonable to suggest that these observed values might be outliers, given their deviations from index values in preceding and following years.

Figure 21: Saithe. Standardised leave one out residuals in the catch and spring survey.
Figure 22: Saithe. Process error residuals.
Figure 23: Saithe. Model fit (solid line) to spring survey data (dots).
Figure 24: Saithe. Model fit (solid line) to catch data (dots).
Figure 25: Saithe. Combined model fit to spring survey indices, solid line is the modelled spring survey index whereas dots indicate the observations.

Stock Assessment Results

The results of the stock assessment are shown in Figure 26. It is evident that until the year 2000, both stock size and catches fluctuated significantly. After 2000, these fluctuations diminished following a reduction in fishing mortality/exploitation rate. Recruitment has fluctuated but remained relatively stable throughout this period. The assessment indicates that the spawning stock biomass (SSB) is currently at its highest recorded levels, although this estimate is accompanied by considerable uncertainty.

The calculated retrospective analysis (Figure 27) indicates that interannual changes in key assessment parameters have been minor despite substantial variability in input data. Consequently, the stock assessment is considered stable, and the calculated five-year Mohn’s \(\rho\) is within acceptable limits.

The estimated stock-recruitment relationship shown in Figure 28 reveals considerable variability in year-class strength. However, there is no clear indication that recruitment has been impaired by the poor condition of the spawning stock during the period covered by the assessment.

Fishing selectivity by size and age is shown in Figure 29. There is considerable variability in fishing patterns across age groups, primarily attributable to changes in fishing effort.

Figure 26: Saithe. Results from the assessment.
Figure 27: Saithe. Analytical retrospective analysis
Figure 28: Saithe. Estimated spawning stock recruitment relationship.
Figure 29: Saithe. Estimated selectivity pattern by age and stock weights.

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. Assessment done in the spring, is used to give advice for the fishing year starting September 1st the same year. For most stocks the spring survey is the most influential data source in the assessment and the most recent spring survey in the assessment year is used for the advice given in June the same year.

The management plan and assessment for Icelandic saithe have been unchanged since 2010 and advice based on the same 20% harvest control rule as used for cod. Since 2014/2015 the set TAC has not been caught but in the period 1997/1998 to 2013/2014 the TAC was caught in all years except 2007/2008 and 2008/2009. The catch in the fishing year 2023/2024 was 40.2 kt while the TAC was 66.7 kt so only 60% of the TAC was caught.

The Icelandic Fisheries management system allows some transfer between species based on cod-equivalence factors that are supposed to reflect the price of the species compared to cod (see ICES, 2021). Transfer to cod is though not allowed in the system that is quite limited. In recent years saithe has been converted to other species (Figure 30) that are probably more economical to catch than saithe. Possibilities of species transfer were recently restricted when transfer to shared stocks like redfish were banned.

Even though some part of the saithe quota has been transferred to other species, a considerable part of the TAC has not been used at all. This is an indication that the saithe fisheries are not very economical, either due to smaller than estimated stock, or difficulty in catching. Historical assessment shows that fishing mortality of Icelandic saithe was never high, even in periods were fisheries were not limited (ICES 2002).

The current management plan for saithe in Icelandic waters was reviewed by ICES in 2025 (ICES, 2025).

Figure 30: Saithe. Net transfer of quota by fishing year. Transfer between species (upper figures): Positive values indicate transfer of TAC from other species to saithe and negative values transfer of saithe quota to other species. Lower figures show net transfer between fishing years.
Figure 31: Saithe. Comparison of the total allowable catch, adviced catch and total catch within the Icelandic EEZ.

Management considerations

All available indicators from commercial catch data and scientific surveys suggest that saithe in Division 5.a is currently in good condition, a conclusion supported by the stock assessment. The TAC has however not been caught in the past years.

References

Bjornsson, H., Hjorleifsson, E., Elvarsson, B. 2019. “Muppet: Program for Simulating Harvest Control Rules.” Reykjavik: Marine and Freshwater Research Institute. http://www.github.com/hoski/Muppet-HCR.

ICES 2019. “Stock Annex: Saithe (Pollachius virens) in Division 5.a (Iceland grounds).” https://ices-library.figshare.com/articles/report/Stock_Annex_Saithe_Pollachius_virens_in_Division_5_aIceland_grounds/18623102

ICES 2025. Workshop on the assessment and management plan evaluation for Icelandic haddock and saithe (WKICEGAD). ICES Scientific Reports. 7:26. 161 pp. https://doi.org/10.17895/ices.pub.28444499

Jakobsen, T., S. Olsen 1987. Variation in rates of migration of saithe from Norwegian waters to Iceland an Fareoe Islands. Fisheries Researh 5:217-222.

Jones, B. W., Jónsson, J. 1971. Coalfish tagging experiments at Icelan. Rit Fiskideildar 5:1-27.

Jónsson, S. Th. 1994. Saithe on a shelf. Two studies of Pollachius virens in Icelandic waters. M.S. Thesis, University of Bergen.

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