PelAC responds to mackerel benchmark, citing stock decline, scientific overhaul, quota abuse, and need for long-term plan
Advisory Council Issues Stark Warning as Scientific Overhaul Confirms Mackerel Decline
The Pelagic Advisory Council (PelAC) has called on the European Commission and coastal states to urgently reform Northeast Atlantic mackerel management following the publication of the latest ICES benchmark report.
In a letter to DG MARE Director-General Charlina Vitcheva dated 14 July 2025, PelAC warns that the mackerel stock, though now assessed with improved scientific methods, remains in long-term decline. The Council blames the continued overexploitation of the stock on years of unilateral quota-setting, the absence of a binding coastal states agreement, and worsening enforcement failures in international waters.
While the benchmark adopts a revised and more robust stock assessment model, PelAC emphasises that the updated science confirms rather than reverses the trend of falling spawning stock biomass (SSB), with the stock now hovering just above the ICES trigger point and projected to fall below Blim within two to three years if excessive catches continue.
Scientific Model Overhauled, But Management Still Lags Behind
The 2025 benchmark introduced major changes to the mackerel assessment model. These include:
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Shifting from fixed to age-based natural mortality rates using the Lorenzen model
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Use of tagging data as an index for age 2–4 mackerel abundance
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Removal of the assumption that fishing selectivity plateaus at age 7
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Increased parameterisation and a new model start date of 1998
These changes led to significantly revised biological reference points. The FMSY was reduced from 0.26 to 0.19, while the biomass trigger reference MSYBtrigger increased from 2.58 million to over 4.1 million tonnes.
Despite these adjustments, the model confirms the decline in SSB since the peak in 2014, highlighting the urgency of halting unsustainable exploitation.
Coastal State Failures and Russian High Seas Fishing in the Spotlight
PelAC criticises the failure of coastal states—including Norway, Iceland, the EU, the Faroe Islands, and the UK—to agree a long-term sharing arrangement. The continued setting of unilateral quotas well above ICES advice has eroded the credibility of scientific management, compounded by misuse of banking and borrowing provisions that enable inter-annual overfishing without formal accountability.
Summer fishing by Russian vessels in international waters is also singled out for criticism. The Council urges the Commission to investigate whether these activities could be designated as illegal, unreported, and unregulated (IUU) fishing under the revised Regulation (EU) 1026/2012, which allows sanctions against countries engaging in non-sustainable practices.
MSE and Rebuilding Plan Now Essential
The Council strongly recommends that the Commission, together with like-minded coastal states, initiate a new Management Strategy Evaluation (MSE) process. This should incorporate:
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Retrospective analysis of implementation error due to consistent over-catch since 2014
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A formal rebuilding plan to prevent the stock from falling below Blim
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Ecosystem-based considerations, including predation, climate-driven changes, and variable natural mortality
PelAC supports use of the ICES Framework for Ecosystem-Informed Science and Advice (FEISA) to test long-term strategies against biological, economic, and social objectives, enabling decision-makers to understand the trade-offs inherent in any future management plan.
Aligning Policy With Science
One major outcome of the benchmark and related genetic research is the confirmation that Northeast Atlantic mackerel is a single stock, contradicting the long-held assumption of three separate components.
PelAC cites work by Naiara Rodríguez-Ezpeleta and genome sequencing research by Leif Andersson and Carl-Johan Rubin as definitive evidence that management rules based on subcomponent structures—such as special TAC provisions for areas 3a, 4b, and 4c—are now obsolete.
The Council calls for the Commission to harmonise the Minimum Conservation Reference Size (MCRS) to 20 cm across all areas and remove outdated quota restrictions for non-existent components in the North Sea.
Data Gaps and New Methods
PelAC highlights ongoing weaknesses in maturity classification, weight-at-age data, and abundance indices. The Council supports increased sampling during peak spawning seasons to improve maturity ogives, continued updating of weight time series, and evaluation of the DEPM (Daily Egg Production Method) as a future index.
New approaches are encouraged, including:
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Industry-led acoustic surveys in the North Sea
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Close-kin mark–recapture methods using mackerel genome data
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Application of IESSNS-based abundance models once published
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Identification of spawning and nursery grounds to reduce anthropogenic impacts
In parallel, PelAC criticises Norway’s decision to withdraw from the egg survey programme, warning that gaps in geographic coverage undermine the scientific basis for shared stock management.
Recruitment Declining Since 2015
The benchmark and previous ICES advice confirm that recruitment has been falling steadily since 2015. Without urgent intervention, stock productivity will remain compromised.
In closing, PelAC reiterates that science alone cannot save the mackerel stock. Without a long-term sharing agreement and coordinated action by coastal states, the improved model will simply document a continuing decline.