Mackerel Scomber scombrus
Publication of Advice: 30 September 2025. Published by Marine and Freshwater Research Institute.
Advice
ICES advises that when the maximum sustainable yield (MSY) approach is applied, catches in 2026 should be no more than 174 357 tonnes.
Stock development
Fishing pressure on the stock is above FMSY and FPA; spawning-stock size is below MSY Btrigger, BPA, and Blim.
Mackerel. Summary of the stock assessment. Catches prior to 2000 have been down-weighted in the assessment because of the considerable underreporting suspected to have taken place in this period.
Basis of assessement and reference points
Basis of the advice | Maximum sustainable yield (MSY) approach |
Management plan | There is no internationally agreed long-term management strategy for Northeast Atlantic (NEA) mackerel |
Assessment type | Age-based analytical model (SAM) |
Input data | Catch data, steel tagging data [L3182] (1998–2006), and three survey indices: SSB index from the triennial egg survey [I4189] (1992–2025), abundance indices for ages 2-11 from RFID tagging data [L5543] (2013–2023), and from the IESSNS survey [A7806] ages 3–11 (2010, 2012–2025) and age 2 (2018-2025). Catches prior to 2000 are given a very low weight in the assessment. Maturity ogive and age-varying natural mortality constant over years. |
Approach | Reference point | Value | Basis |
|---|---|---|---|
MSY | MSY Btrigger | 4 119 337 | BPA; tonnes |
FMSY | 0.191 | Stochastic simulations, capped at FPA | |
Precautionary approach | Blim | 3 067 017 | Lowest spawning-stock biomass (SSB) level that in the past has resulted in good recruitment (2002, 2004, 2005) (ICES, 2025a); tonnes |
BPA | 4 119 337 | Blim × exp (1.65 × σ), σ = 0.179; tonnes | |
FPA | 0.191 | The F that provides a 95% probability for SSB to be above Blim (FP05 with advice rule) |
Prospect
Mackerel. Assumptions made for the interim year and in the forecast.
Variable | Value | Notes |
|---|---|---|
Fages 4–8 (2025) | 0.29 | From the forecast for 2025, based on assumed catch in 2025 |
SSB (2025) at spawning time | 2 740 823 | From the forecast for 2025; tonnes |
Rage 2 (2026-2027) | 4 659 625 | Resampled recruitments from the years 2017–2025 (geometric mean shown); thousands |
Total catch (2025) | 755 143 | Sum of expected landings and discards, discards based on the observed landings in the first half of the year, accounting for the interannual transfers from 2024; tonnes |
Mackerel. Annual catch scenarios. All weights in tonnes.
Basis | Catch (2026) | Fishing mortality (2026-2027) | SSB (2026) | SSB (2027) | % SSB change1) | % Catch change2) | Advice change3) | % probability of falling below Blim in 2027 |
|---|---|---|---|---|---|---|---|---|
SSB2027 = Blim | 174 357 | 0.072 | 2 752 834 | 3 067 887 | 11.4 | -77 | -70 | 50 |
F = F2025 | 630 387 | 0.29 | 2 671 278 | 2 685 274 | 0.52 | -16.5 | 9.3 | 75 |
1) SSB in 2027 relative to SSB in 2026 | ||||||||
2) Catch in 2026 relative to estimated catches in 2025 (755 143 t) | ||||||||
3) Advice value for 2026 relative to advice value for 2025 (576 958 t) | ||||||||
The change in advice (−70%) is due to the decline in the stock size, a reduction in advised fishing pressure to achieve a 50% probability of spawning-stock biomass (SSB) being above Blim in 2027 (because SSB2025 is below Blim) and the change in the perception of the stock after the benchmark.
Quality of the Assessement
The stock was benchmarked in 2025 (ICES, 2025a). Several changes were made, including the use of a new age-varying natural mortality, the use of radio-frequency identification (RFID) data as an abundance-at-age index in place of the raw recapture data, the inclusion of abundance indices for the younger ages from the IESSNS survey (age 2) and the tagging data (age 2−4). In addition, the assessment period was shortened (now starting in 1998), and the minimum age of fish included in the assessment increased from 0 to 2.
These changes resulted in an upward revision in the estimated stock size and downward revision in fishing mortality, mostly because of the new natural mortality assumption, and a corresponding revision to biomass (upwards) and fishing mortality (downwards) reference points. The benchmark led to an improvement of the retrospective pattern (upward revisions of stock size around 2015), and to more accurate recruitment estimates (now at age 2, informed by two indices and catch information).
Following the inclusion of a new year of data since the benchmark, the assessment of the state of the stock remains consistent but with a lower uncertainty in the estimated stock size and fishing mortality.
Mackerel. Current assessment (red line) compared with previous estimates (2021–2024). Prior to 2022, recruitment was presented as age 0 and is not shown.
Other Information
The sum of the unilateral quotas for mackerel has resulted in catches that have exceeded the scientific advice by, on average, 39% since 2010. The stock is estimated to be below both MSY Btrigger and Blim in 2025. The advice is based on the MSY approach that should lead to a short-term recovery above Blim and a medium-term recovery above MSY Btrigger. Failing to adhere to the advised catches as derived from the application of the MSY approach may lead to a lower chance of the stock recovering to above Blim in the short term and to above MSY Btrigger in the longer term.
Following the guidelines, to provide advice for stocks below Blim, 2017−2025 was selected as the time period to calculate the recruitment in the forecast to reflect the currently observed low stock productivity.
The advice for 2026 is based on a fishing mortality that leads to a 50% probability of SSB being above Blim in 2027. The forecasted SSB in 2027 is composed of more than 40% of age 2 and age 3 fish, for which the abundances are based on recruitment assumptions, rather than assessment estimates. Therefore, the forecasted SSB in 2027 and the advice are sensitive to the forecast assumptions.
Advice, tac and catch
Mackerel. Recommended TAC, national TAC, and catches (tonnes).
Year | Recommended TAC | Iceland national TAC | Catches Iceland | Total national TAC | Total catch |
|---|---|---|---|---|---|
1987 | 0 | 442 000 | 654 992 | ||
1988 | 0 | 610 000 | 680 491 | ||
1989 | 0 | 532 000 | 585 920 | ||
1990 | 0 | 562 000 | 626 107 | ||
1991 | 0 | 612 000 | 675 665 | ||
1992 | 0 | 707 000 | 760 690 | ||
1993 | 0 | 767 000 | 824 568 | ||
1994 | 0 | 837 000 | 819 087 | ||
1995 | 0 | 645 000 | 756 277 | ||
1996 | 92 | 452 000 | 563 472 | ||
1997 | 925 | 470 000 | 573 029 | ||
1998 | 498 000 | 357 | 549 000 | 666 316 | |
1999 | 437 000 | 0 | 562 000 | 640 309 | |
2000 | 642 000 | 0 | 612 000 | 738 606 | |
2001 | 665 000 | 0 | 670 000 | 737 463 | |
2002 | 694 000 | 53 | 683 000 | 771 422 | |
2003 | 542 000 | 122 | 583 000 | 679 287 | |
2004 | 545 000 | 0 | 532 000 | 660 491 | |
2005 | 420 000 | 363 | 422 000 | 549 514 | |
2006 | 487 000 | 4 222 | 444 000 | 481 181 | |
2007 | 509 000 | 36 706 | 502 000 | 586 206 | |
2008 | 456 000 | 112 286 | 458 000 | 623 165 | |
2009 | 578 000 | 116 160 | 605 000 | 737 969 | |
2010 | 572 000 | 130 000 | 121 008 | 885 000 | 877 272 |
2011 | 672 000 | 154 825 | 159 263 | 959 000 | 948 963 |
2012 | 639 000 | 145 227 | 149 282 | 927 000 | 899 551 |
2013 | 542 000 | 123 182 | 151 235 | 906 000 | 938 299 |
2014 | 1 011 000 | 167 826 | 173 560 | 1 392 000 | 1 401 788 |
2015 | 906 000 | 172 964 | 169 336 | 1 229 000 | 1 215 827 |
2016 | 773 842 | 147 824 | 172 079 | 1 057 000 | 1 100 135 |
2017 | 857 185 | 168 464 | 167 366 | 1 173 000 | 1 159 641 |
2018 | 550 948 | 134 772 | 168 331 | 998 000 | 1 023 144 |
2019 | 770 358 | 140 240 | 128 077 | 864 000 | 839 727 |
2020 | 922 064 | 152 141 | 151 534 | 1 090 879 | 1 039 513 |
2021 | 852 284 | 140 627 | 132 176 | 1 199 103 | 1 081 540 |
2022 | 794 920 | 148 242 | 129 976 | 1 188 227 | 1 046 720 |
2023 | 782 066 | 144 039 | 141 369 | 1 188 265 | 1 056 241 |
2024 | 739 386 | 115 533 | 89 614 | 990 582 | 897 701 |
2025 | 576 958 | 125 572 | 760 714 | ||
2026 | 174 357 |
References and further reading
ICES. 2020. Workshop on Management Strategy Evaluation of Mackerel (WKMSEMAC). ICES Scientific Reports. 2:74. 175 pp. http://doi.org/10.17895/ices.pub.7445
MFRI Assessment Reports 2025. Mackerel. Marine and Freshwater Research Institute, 30 September 2025.
ICES. 2025a. Benchmark workshop on Mackerel and Norwegian spring-spawning herring (WKBMACNSSH). ICES Scientific Reports. 7:64. 509 pp. https://doi.org/10.17895/ices.pub.29279615
ICES. 2025. Mackerel (Scomber scombrus) in subareas 1-8 and 14 and Division 9.a (the Northeast Atlantic and adjacent waters). In Report of the ICES Advisory Committee, 2025. ICES Advice 2025, mac.27.nea. https://doi.org/10.17895/ices.advice.27202689
ICES. 2025c. Working Group on Widely Distributed Stocks (WGWIDE). ICES Scientific Reports. https://doi.org/10.17895/ices.pub.30233824