HERRING Clupea harengus
Publication of Advice: 6. June 2025. Published by Marine and Freshwater Research Institute.
Advice
MFRI and ICES advise that when the Icelandic management plan is applied, catches in the fishing year 2025/2026 should be no more than 103 367 tonnes.
Stock development
Fishing pressure on the stock is below HRMGT, HRpa and HRMSY. Spawning stock size is above Btrigger, Bpa and Blim.
Herring. Catch by gear type, recruitment, harvest rate based on reference stock biomass (B4+). All biomass reference points refer to SSB levels (MSY Btrigger = MGT Btrigger = Bpa).
Basis of the assessment and reference points
Basis of the advice | Management plan |
Management plan | TAC set as 19 % of reference biomass (biomass of 4+) |
Assessment type | Statistical catch at age model |
Input data | Catch in numbers and age disaggregated indices from accoustic surveys |
Approach | Reference point | Value | Basis |
|---|---|---|---|
MSY | MSY Btrigger | 273 000 | Bpa |
HRMSY | 0.221 | Stochastic MSE simulations. | |
Management plan | MGT Btrigger | 273 000 | From the Management plan (MSY Btrigger) |
HRMGT | 0.19 | From the Management plan | |
Precautionary approach | Blim | 200 000 | SSB beyond which recruitment becomes impaired |
Bpa | 273 000 | Bpa = Blim × exp(1.645 × σ), σ = 0.19 | |
HRpa | 0.248 | Harvest rate leading to P (SSB > Blim) > 95% with MSY Btrigger |
Prospects
The Icelandic Ministry of Industries management plan was implemented in 2024. The rule was evaluated by ICES (ICES, 2024) and is considered to be precautionary and to conform to ICES MSY approach. According to the rule, the TAC for the fishing year Y/Y+1 (01 September of year Y to 31 August of year Y+1) is calculated as follows:
\[ \text{TAC}_{Y/Y+1}=\text{min}\left(\frac{\text{SSB}_Y}{\text{MGT B}_{trigger}} ,1\right) \text{HR}_{\text{MGT}} B_{4+,Y} \]
The spawning-stock biomass trigger (MGT Btrigger) is defined as 273 000 tonnes; B4+ is defined as the biomass of herring of ages 4 and older, and the target harvest rate (HRMGT) is set to 0.19.
Herring. Assumptions made for the interim year and in the forecast.
Variable | Value | Notes |
|---|---|---|
Catch (2024/2025) | 82 210 | Reported catch from June 2024 to the end of April 2025; tonnes. |
HR (2024/2025) | 0.14 | Harvest rate based on catch constraint |
Recruitment age 2 (2025) | 545 116 | Estimated by the model; in thousands |
B4+ (2025) | 544 037 | From the assessment (1. January 2025); tonnes |
SSB (2025) | 517 273 | Predicted (1 July 2025) after accounting for Ichthyophonus infection in 2024; in tonnes |
B4+ (2026) | 476 287 | From the assessment (1. January 2026); tonnes |
Recruitment age 2 (2026) | 544 228 | Mean of the past 10 years of the assessment; in thousands |
Herring. Projection of reference biomass and SSB (tonnes) based on harvest control rule.
Basis | Catch (2025/2026) | Harvest rate (2025/2026) | SSB (2027)1) | % SSB change2) | Advice change3) |
|---|---|---|---|---|---|
Management plan | 103 367 | 0.19 | 453 588 | -12 | 27 |
1) SSB on 1 July 2026 | |||||
2) SSB in 2026 relative to SSB in 2025 | |||||
3) Advice value for 2026/2025 relative to advice value for 2025/2024 81367 | |||||
The advice has increased because of an upward revision of spawning biomass estimates.
Quality of the Assessment
Since 2024 the stock has been assessed using an analytical age-based assessment model (SAM; ICES, 2024b).
Ichthyophonus infection mortality has been re-evaluated for the period 2008–2024, resulting in the application of lower infection mortality than previously used.
There have been technical issues with the acoustic surveys in the last two years that may result in increased uncertainties around the population estimates.
Herring. Current assessment (red line) compared with previous estimates (2021–2024). The reference points and assessment were revised in 2024, and only assessment results from the last year should be compared to the reference points indicated.
Other information
Ichthyophonus infection still persists in the stock, but at lower prevalence than previously. This impact is incorporated in both the assessment and the management plan.
Advice, TAC and Catch
Herring. Recommended TAC, national TAC, and catches (tonnes). Catches represents sum of the winter catches and the summer catches in the preceding fishing year.
Fishing year | Recommended TAC | National TAC | Total catch |
|---|---|---|---|
1984 | 50 000 | 50 000 | 50 300 |
1985 | 50 000 | 50 000 | 49 400 |
1986 | 65 000 | 65 000 | 65 509 |
1987 | 70 000 | 72 900 | 75 400 |
1988 | 100 000 | 90 000 | 92 800 |
1989 | 95 000 | 90 000 | 101 000 |
1990/1991 | 90 000 | 100 000 | 105 100 |
1991/1992 | 79 000 | 110 000 | 109 500 |
1992/1993 | 86 000 | 110 000 | 108 510 |
1993/1994 | 110 000 | 110 000 | 102 700 |
1994/1995 | 83 000 | 130 000 | 134 000 |
1995/1996 | 120 000 | 110 000 | 125 850 |
1996/1997 | 97 000 | 110 000 | 95 850 |
1997/1998 | 90 000 | 100 000 | 64 930 |
1998/1999 | 90 000 | 90 000 | 87 240 |
1999/2000 | 100 000 | 100 000 | 92 900 |
2000/2001 | 110 000 | 110 000 | 100 330 |
2001/2002 | 125 000 | 125 000 | 101 400 |
2002/2003 | 113 000 | 105 000 | 96 100 |
2003/2004 | 113 000 | 110 000 | 126 000 |
2004/2005 | 106 000 | 110 000 | 115 000 |
2005/2006 | 110 000 | 110 000 | 103 050 |
2006/2007 | 110 000 | 130 000 | 135 310 |
2007/2008 | 117 000 | 150 000 | 158 900 |
2008/2009 | 131 000 | 130 000 | 151 780 |
2009/2010 | 75 000 | 40 000 | 46 000 |
2010/2011 | 40 000 | 40 000 | 43 533 |
2011/2012 | 40 000 | 45 000 | 49 446 |
2012/2013 | 67 000 | 68 500 | 72 236 |
2013/2014 | 87 000 | 87 000 | 72 058 |
2014/2015 | 83 000 | 83 000 | 94 975 |
2015/2016 | 71 000 | 71 000 | 69 729 |
2016/2017 | 63 000 | 63 000 | 60 403 |
2017/2018 | 38 712 | 39 000 | 35 034 |
2018/2019 | 35 186 | 35 186 | 40 683 |
2019/2020 | 34 572 | 34 572 | 30 041 |
2020/2021 | 35 490 | 35 490 | 36 041 |
2021/2022 | 72 239 | 72 239 | 70 084 |
2022/2023 | 66 195 | 66 195 | 72 804 |
2023/2024 | 92 633 | 92 633 | 94 422 |
2024/2025 | 81 367 | 81 367 | 82 210 |
2025/2026 | 103 367 |
References and further reading
MFRI Assessment Reports 2025. Herring. Marine and Freshwater Research Institute, 6 June 2025.