Herring

Herring in the Irish Sea (South), Celtic Sea and southwest of Ireland is below safe biological levels and there are no measures or plans in place to help it recover. Therefore, it receives a critical fail for stock status and is a default red rating.

Stock assessments are carried out annually by the International Council for the Exploration of the Sea (ICES). The most recent stock assessment was published in 2025 using data up to 2024. The next assessment is expected in 2026.

The stock assessment defines reference points for fishing pressure (F) and biomass (B). For fishing pressure, there is a target to keep F at or below Maximum Sustainable Yield (MSY). For biomass, there is no target. However, there is a trigger point (MSY BTrigger). Below this level, F should be reduced to allow the stock to increase. Because BMSY is not defined, the Good Fish Guide applies its own definition of 1.4 x MSY BTrigger.

The spawning-stock biomass (SSB) of herring within this area significantly decreased from around 200,000 tonnes in the late 1950s to around 7,500t in the 1970s. It has fluctuated since then, but reached an all-time low of 7,207t in 2018. There has been a small increase since then to 20,065t in 2024 and the short term forecast predicts a further increase in 2025 to 22,292t. However, this remains below the level at which the stock's ability to reproduce may be impaired (Blim: 34,000 tonnes). The stock is therefore in a very overfished state, outside safe biological limits, and suffering reduced reproductive capacity. Due to this this ratings receives a critical fail.

Fishing mortality (F) had been above levels associated with Maximum Sustainable Yield (FMSY, 0.26) for most of the history of the fishery. In 2013 it reached a low of 0.20, then dramatically increased to 1.11 in 2017. It declined again in 2020 to an all-time low of 0.017. In 2024, F was 0.058 remaining low and below FMSY. This indicates that the stock is not subject to overfishing.

ICES advises that when the MSY approach and precautionary considerations are applied, there should be zero catch in 2026. Zero catch has been recommended since 2020 because there are no catch scenarios that will allow the stock to recover to above Blim by 2027.

Recruitment of young fish into the stock has been declining since 2011 (956,829 t), and is thought to have reached an all-time low in 2021 (56,685 t). Recruitment have been increasing since then with 286,770 in 2024. However, recruitment in 2025 is estimated to decline to 124,841t. These estimates are uncertain, due to a lack of data.

Juvenile Celtic Sea herring mix with the Irish Sea stock, but the level of mixing is unknown. This could affect management and advice.

For this autumn-spawning stock, the SSB is determined at spawning time and influenced by fisheries between 1st April and spawning (October). Herring stocks are surveyed using acoustic surveys, but as they have been observed close to the sea bed in recent years this may not be the most reliable estimate, and it makes the stock assessment more uncertain. SSB is consistently overestimated and fishing mortality is consistently underestimated, so the assessment is considered to be highly uncertain. However, the uncertainty of the assessment does not impact the outcome of the advice.

Area 7h (Celtic Sea South) is part of the management area, but it is unclear if it is part of the stock.

This fishery has a default red rating due to biomass concerns.

Some management measures are in place for this fishery, but there is no precautionary recovery plan to help herring recover to safe biological levels. For 2019 to 2026 ICES has advised that there should be zero catch of this stock. However, a scientific fishery is in place to allow for ongoing stock assessments, so a monitoring Total Allowable Catch (TAC) of 869 tonnes was in place for 2020-2025.

The EU and UK both have fishery management measures, which can include catch limits, population targets, and gear restrictions. However, compliance in the EU and UK has been inconsistent, with ongoing challenges in implementing some regulations. The goal of reaching Maximum Sustainable Yield (MSY) by 2020 was missed, with less than half of UK TACs in 2024 following ICES advice. In 2024, the EU and UK reaffirmed their commitment to sustainable fisheries by aligning management with scientific advice to gradually approach MSY. However, no new target date has been set for achieving MSY across all fisheries. The Landing Obligation (LO), an EU law retained by the UK post-Brexit, requires all quota fish to be landed, even if unwanted (over-quota or below minimum size). It aims to encourage more selective fishing methods, reduce bycatch, and improve catch reporting. However, compliance is poor, and accurate discard levels are hard to quantify with current monitoring programmes. The UK is in the process of replacing the LO with country-specific Catching Policies.

The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.

The Fisheries Act (2020) requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans) in the UK. 43 FMPs have been proposed and are at various stages of development and implementation, these should all be published by the end of 2028. FMPs have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. It is also essential the UK governments define and adopt a standardised approach or model across the four nations to a universally defined FMP design, to ensure the consistence, quality and coherence of all the proposal FMPs.

The Marine Conservation Society is keen to see publicly available Fishery Management Plans for all commercially exploited stocks, especially where stocks are depleted, that include:

• An overview of the fishery including current stock status, spatial coverage, current fishing methods and impacts
• Targets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best scientific evidence
• Timeframes for stock recovery
• Improved data collection, transparency, and accountability, supported by technologies such as Remote Electronic Monitoring (REM)
• Consideration of wider environmental impacts of the fishery, including habitat impacts and minimising bycatch
• Stakeholder engagement

This fishery has a default red rating due to biomass concerns.

Herring in the Irish Sea (South), Celtic Sea and southwest of Ireland are caught by pelagic trawls. ICES advice is that no catch should be taking place by any method, although a TAC has been set for scientific monitoring.

Low herring biomass may alter the wider ecosystem as herring graze on plankton and act as prey for other organisms. Herring are an important food source for marine mammals such as fin whales and larger gadoids such as hake in the Celtic Sea.

To improve monitoring and reporting of fishing activity, MCS would like to see remote electronic monitoring (REM) with cameras implemented, used and enforced. To reduce the impacts of fishing on the marine environment we would like to see a just transition to the complete removal of bottom towed gear from offshore Marine Protected Areas designated to protect the seabed. We also want to see reduction and mitigation of environmental impacts including emissions and blue carbon habitat damage.