North Sea Herring Fisheries Management Plan

Environmental considerations

Conservation advice

FMPs are subject to legal duties and requirements relating to the protection of the natural environment arising from legislation such as the Habitats Regulations, the Marine Strategy Regulations 2010, and the UK Marine Policy Statement, the Environment Act 2021, Marine and Coastal Access Act 2009, and the Marine (Scotland) Act 2010.

Alongside these requirements, FMPs seek to support a range of other existing environmental policies that focus on enhancing the health of our seas for future generations, restoring marine biodiversity and tackling the causes and impacts of climate change. To support the development of policies aimed at protecting the natural environment, Statutory Nature Conservation Bodies (SNCBs) provided conservation advice for the Scottish-led pelagic FMPs.

Advice provided to fisheries policy authorities by SNCBs gives more detail on the risks associated with fishing for species covered by the pelagic FMPs in relation to the protected features of MPAs, Priority Marine Features (PMFs) for Scotland and UK Marine Strategy Descriptors (UK MS). Joint advice from JNCC and NatureScot, commissioned by the Scottish Government's Marine Directorate and covering Scottish waters, was received for pelagic FMPs in Scottish waters as part of a single assessment. Additional joint advice from Natural England and JNCC, commissioned by Defra and covering English waters, was received for the draft Northern Shelf Blue Whiting FMP, Northern Shelf Mackerel FMP, North Sea Greater Silver Smelt FMP, North Sea Herring FMP, and North Sea Horse Mackerel FMP. Advice for Welsh waters, developed by Natural Resources Wales (NRW) in collaboration with JNCC, was also received for the draft Northern Shelf Blue Whiting FMP and the draft Northern Shelf Mackerel FMP.

Methodology

The SNCBs developed a ‘risk rating’ which is intended to help identify where the greatest impacts of fishing are likely to occur. A three-point scale has been used in the conservation advice: low, moderate and high risk.

• Low risk - An impact pathway exists, but evidence or expert opinion suggests that impacts are minimal or unlikely.
• Moderate risk – Interactions rated as moderate risk typically have an evidenced impact or expert judgment indicates a genuine risk, but factors such as evidence gaps around the scale of impact or exposure to pressures, existing mitigations, or difficulties disentangling impact sources, make it difficult to determine whether the risk is high or low. This precautionary approach to risk assessment is aimed at managing identified risks proactively while acknowledging gaps in current understanding. SNCB advice recommends that FMPs consider enhanced data collection or mitigation options if a moderate risk is identified, taking a proactive approach towards minimising impacts.
• High risk - Interactions identified as high risk are those where available evidence or expert opinion suggests there is an impact at such a scale as is likely to require mitigation.

In contrast to the SNCBs routine advice on environmental sensitivity of distinct habitats or species, the methodology developed specifically for the conservation advice on FMPs provides ‘indicative risk ratings’ on pelagic fisheries in general. These ratings consider the scale of risk associated with the different components of the pelagic fisheries in Scottish and English waters to help identify where the greatest impacts are likely to occur.

The conservation advice provided practical guidance on the most significant risks associated with the interactions between the fishing gear types used to target pelagic fish and the protected features of Marine Protected Areas (MPAs), Priority Marine Features (PMFs)^[14] (Scottish waters only) and UK Marine Strategy descriptors.

Summary

The conservation advice highlighted several moderate environmental risks associated with pelagic fisheries in UK waters, including:

• bycatch of fish, marine mammals and birds in the fisheries
• prey reduction, and
• the introduction of marine litter.

Details on the risks to MPAs, PMFs and UK Marine Strategy Descriptors are set out in the below, and more detail can be found in the published conservation advice.

MPAs and PMFs in Scottish Waters

Fisheries contained in the pelagic FMPs have the potential to impact the protected features of MPAs and on PMFs in 2 primary ways;

• through the bycatch of protected features of MPAs/PMFs, and
• the direct (targeted) and indirect (bycatch) removal of prey species on which protected and PMF species depend.

MPAs – risk summary

Evidence suggests that pelagic trawl and purse seine fisheries pose a relatively low risk to the MPA designated marine mammal and fish species features in terms of bycatch^[15], with limited records of bycatch of harbour porpoise, grey seals, basking shark and ‘common’ skate. However, due to low sampling effort, improved evidence is needed to support a low risk rating for these species.

Several MPA designated bird species features are considered sensitive to bycatch in these fisheries; guillemot, razorbill and cormorant have all been recorded as bycatch in pelagic trawls. In light of limited evidence on bycatch and based on the potential sensitivity to bycatch, expert advice suggests the risk ought to be classed as moderate.

Owing to gaps in the available evidence, the risk rating for bycatch in pelagic fisheries is considered moderate. However, with the introduction and rollout of REM to UK pelagic fishing vessels, this will enhance the evidence base and could lead to a downgrading of the risk in the future.

This topic is explored further in Policies 3 and 4.

All the fish species managed through the pelagic FMPs are considered prey species for a broad range of predators and as such, are an important part of the marine ecosystem around Scotland. There is good evidence to demonstrate that many of the pelagic species covered in the pelagic FMPs are key prey for many of the designated fish, marine mammal, and seabird features in Scottish MPAs. However, the extent to which features rely on specific pelagic prey species is less clear. As such, the risk rating for pelagic fisheries in Scottish waters regarding removal of important prey species that designated species depend on is considered moderate.

This topic is explored further in Policies 1, 2 and 4.

PMFs (Scotland only)– risk summary

As discussed above for MPA features, pelagic fisheries are not expected to pose a substantial risk of bycatch; however, as evidence gaps remain this has resulted in a precautionary rating of ‘moderate’ for PMF bycatch. Addressing evidence gaps through the collection of REM data, or through enhanced data collection will improve confidence in the assessment of bycatch risks, and may result in a downgrading of the risk in the future.

This topic is explored further in Polices 3 and 4.

Several marine mammal and fish PMFs, in addition to those species designated as MPA features, are likely to utilise pelagic species at various life stages as a prey resource. Though they exhibit a variety of foraging strategies, many killer whale groups, including those that visit Scottish waters, are fish-eating specialists, feeding almost exclusively on schooling pelagic fish species such as herring and mackerel. Fin whales feed on small schooling fish species such as herring and sprat. Herring and mackerel are also important prey species for adult porbeagle. Many of the species targeted by fisheries listed under the pelagic FMPs are important prey species for a variety of cetaceans and fishes, including species of conservation interest which are not listed as PMFs, such as the humpback whale. There is a lack of evidence available in relation to the overall ecosystem interactions, and therefore a moderate risk to PMFs (fish, marine mammals) through removal of key prey species in pelagic fisheries is concluded.

This topic is explored further in Policy 4.

MPAs in English Waters

The main impacts of the fisheries incorporated in this FMP on the protected features of MPAs arising from fishing activity outside MPA site boundaries, with an indication of their risk level, are summarised below.

• There is a moderate risk of bycatch of mobile species that are protected features of MPAs in pelagic trawls, ringnets, purse seines, and pelagic drift nets
• There is a moderate risk to the protected species of MPAs from reductions in their prey through the targeted sprat fishery.

UK Marine Strategy Descriptors

Background

The UK Marine Strategy Regulations 2010 (SI 2010/1627) provide the policy framework for delivering marine environmental policy at the UK level and set out how the vision of clean, healthy, safe, productive, and biologically diverse oceans and seas will be achieved. The Regulations require the Secretary of State, in consultation with the devolved authorities to define the characteristics of Good Environmental Status (GES). In turn the Secretary of State and devolved policy authorities must develop an associated Programme of Measures to deliver this. The UK Marine Strategy Part Three: UK Programme of Measures outlines the actions and initiatives the UK is taking to do this.

The advice focussed only on the most relevant descriptors in terms of risks posed by commercial and recreational fisheries: D1 biodiversity, D3 commercial fish and shellfish, D4 foodwebs, D6 seafloor integrity and D10 marine litter. In the UK Marine Strategy (UK MS) these descriptors are assessed using indicators for each of their constituent ‘ecosystem components.’ The assessment was undertaken by providing advice on the risks to eight descriptor-ecosystem component combinations:

• Cetaceans - D1, D4
• Seals - D1, D4
• Seabirds - D1, D4
• Fish - D1, D4
• Foodwebs - D4
• Seafloor integrity - D1, D6
• Marine litter - D10

The results of an initial consideration of the available evidence and expert opinion of the main risks arising from the fisheries covered by the pelagic FMPs to UK MS Descriptors are summarised below.

Risk summary

There is a moderate risk to achieving GES for the biological diversity of cetaceans, seals, and birds, due to impacts from pelagic fishing activities related to bycatch and through targeted removal of herring, as an important prey species. However, it is important to understand the differences between fishing methods. For trawl vessels, it is thought they have relatively little bycatch risk (although evidence could be improved – as set out already). The lack of evidence to provide a confident assessment of bycatch risk suggests the risk is likely to be moderate. Given the importance of pelagic stocks within the UK marine ecosystem, the potential to impact prey availability needs further consideration for pelagic fisheries.

This topic is explored further as part of Policy 4.

There is a moderate risk to marine litter, with limited evidence available to help disentangle the relative contribution of pelagic fisheries to marine litter. The conservation advice indicates that more robust estimates of abandoned, lost, or discarded fishing gear from pelagic fisheries are required.

The advice also acknowledges that fishing litter is likely to be a relatively small component of overall marine litter, therefore fishing measures alone are unlikely to contribute significantly to the achievement of GES. In Scotland a range of actions are undertaken to address issues with marine litter, as set out in the Marine Litter Strategy for Scotland^[16] and these will continue to be delivered as part of a separate programme of work.

It should be noted that there is ongoing work with regard to the Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) to implement the second Regional Action Plan on Marine Litter. This includes action to tackle marine litter from land and sea-based sources, including fishing.

Context and interpretation of the conservation advice^[17]

On bycatch, the moderate risk relates to the limited evidence base, and can be classed as a precautionary rating. Given that REM policies for the Scottish pelagic fleet (which are the main pelagic targeting vessels in the UK) are well advanced, and that positive steps are being undertaken elsewhere in the UK to introduce REM, this evidence gap will be addressed, and this is noted within the FMP.

On predator/prey interaction, many pelagic species are integral parts of the wider food web and can often be key predatory and/or prey species. Whilst these interactions between different parts of the food chain are understood, at the present time, ICES do not fully account for these interactions and the needs of predators in its annual advice. However, management decisions that incorporate ecosystem‑based fisheries management (EBFM) considerations may nonetheless be justified where they are supported by wider fisheries science and evidence. Actions to consider this further are contained in the policies and actions section.

On marine litter, there are two main considerations, firstly the risk that fishing in general, (rather than specifically pelagic fishing) presents to marine litter overall, and secondly, gaps in evidence. These two considerations have resulted in a moderate risk rating. However, the fisheries policy authorities do not believe that there is a prevalence or significant risk of marine litter in pelagic fisheries and therefore a specific action on this is not included within the FMP, although positive action is being taken by the UK, through OSPAR, on this, as set out above.

As noted within the FMPs, the pelagic fishing industry is largely regarded as a relatively clean fishery. In general terms, pelagic fish tend to school together as a species, meaning that different species can be targeted by fishing vessels rather than being caught as part of a mixed fishery. This reduces, although doesn’t eliminate, unwanted catches of fish that aren’t the target species. In the UK there is currently a requirement under fishing vessel licence conditions for all fishing vessels operating in UK waters to report any bycatch (incidental mortality or injury) of marine mammals to the Marine Management Organisation (MMO) within 48 hours of the end of the fishing trip. As of August 2025, no marine mammal bycatch has been reported in Scottish waters to the Marine Management Organisation. Finally, the main fishing fleet targeting pelagic species operates with trawls that rarely come into contact with the seabed, meaning that benthic disturbance is generally not an issue. This is important context in considering the conservation advice and whether any new management action is necessary.

Climate Change

Climate Change impacts on pelagic fish

Pelagic fish stocks (including mackerel, herring and blue whiting) are among the most economically valuable and climatically sensitive fisheries in UK waters and the wider Northeast Atlantic (ICES, 2023^[18]; Garrett et al., 2024^[19]). The existing evidence shows that climate change is already reshaping pelagic fish distributions, productivity and ecosystem interactions, creating significant challenges for fisheries management systems which are largely based on historical conditions (Baudron et al., 2020^[20]; Townhill et al., 2023^[21]).

While able to respond rapidly to temperature over much of their lifecycle, pelagic species (including herring, mackerel, blue whiting and horse mackerel) may still be constrained by the need to spawn at specific localities that promote the transport of offspring to suitable nursery areas and the many seem to adopt a relatively demersal habit during this phase (Heath et al., 2012^[22]; Wright et al., 2020^[23]). Spawning locations for some pelagic species such as mackerel have changed, and this is possibly linked to climate but transport to suitable nursery habitats is also a factor (Fox C J et al., 2023^[24]).

Pelagic species respond to warming seas faster and over greater distances than most demersal fish because they closely track temperature and plankton availability (Baudron et al., 2020; Montero‑Serra et al., 2015^[25]).

Key observed patterns include:

• Strong poleward shifts^[26] of both warm‑affinity and temperate pelagic species (Baudron et al., 2020; Townhill et al., 2023)
• Extreme mobility of Northeast Atlantic mackerel, whose centre of distribution shifted ~1,650 km west and ~400 km north between 2007–2016 (Garrett et al., 2024; Ólafsdóttir et al., 2019^[27])
• Northward re‑centring of boreal pelagic stocks (e.g. herring, blue whiting) into Norwegian, Icelandic and Barents Sea waters (Pinnegar et al., 2023^[28]; Garrett et al., 2024)
• Altered pelagic fish productivity with sea temperature impacting on spawning and larval survival (Petitgas et al., 2013^[29]; Pinnegar et al., 2023)
• Increasing presence of warm‑water pelagics (e.g. sardine‑ and anchovy‑like species) in and around the North Sea (Montero‑Serra et al., 2015; Townhill et al., 2023).

Recent warm years have produced strong year classes for some pelagic species (e.g. mackerel, blue whiting, sprat), but responses are highly variable across species and regions (Garrett et al., 2024). Under high‑emissions scenarios, productivity outcomes diverge (Townhill et al., 2023; Garrett et al., 2024;).

Herring populations show strong natural variability, with abundance fluctuating over short time periods. These dynamics are influenced by environmental factors such as temperature, prey availability, and predation, which affect recruitment, mortality, and distribution (ICES, 2024^[30]). This suggests that ecosystem-based reference points incorporating environmental and predator–prey interactions may be more ecologically relevant than traditional MSY approaches (Bentley et al., 2021^[31]; ICES WKIRISH6, 2019^[32]). For NSAS herring, temperature plays an important role, with warmer waters linked to faster growth but higher mortality and smaller maximum size. Continued warming is therefore likely to affect future stock dynamics. Recruitment has declined in recent years, with possible drivers including reduced larval survival, as well as wider anthropogenic pressures such as seabed extraction and fossil fuel activity.

See Table 2 below for climate related changes and projected direction for this stock:

Table 2. Climate related changes and projected direction of change for NSAS

Stock

North Sea Autumn Spawning (NSAS) herring

Current Stock Type / Thermal Affinity

Cold‑water pelagic, southern range edge in North Sea; shows natural variability; abundance and distribution are influenced by environmental factors, including temperature, predator abundance and prey availability

Observed Climate‑Related Changes

Contraction from southern areas, altered spawning timing, weaker recruitment in warm years

Projected Direction of Change (to ~2050)

Declining habitat suitability in southern & central North Sea; gradual northward retreat

Management systems for these stocks are tied to historical distributions (e.g. fixed quota shares) and are becoming progressively misaligned with biological reality (Baudron et al., 2020). Stock productivity is becoming increasingly impacted by climate change making it less predictable, increasing uncertainty around reference points, MSY estimates and harvest control rules (ICES, 2023; Townhill et al., 2023). Adaptive and precautionary approaches will be increasingly necessary.

Herring is an important forage species and pelagic prey and food webs (Engelhard et al., 2014^[33]; Lawrence et al., 2016^[34]), and climate-driven changes may alter predator–prey interactions, prey availability and stock productivity (Fox et al., 2023). Pelagic fisheries increasingly require ecosystem‑based management, particularly for forage species such as herring and sprat (ICES, 2023).

Marine heatwaves and temperature anomalies add short‑term shocks on top of long‑term warming and while these heatwaves may not permanently reduce pelagic biomass, they increase ecological volatility and uncertainty (Smale et al., 2019^[35]).

Vessel emissions

In addition to the impacts of climate change on pelagic fish and on the fisheries who target these fish, and the need to adapt to these changes, it is also important to consider climate change mitigation (and net zero targets) in relation to fishing. The UK administrations have different targets relating to climate change and are developing plans to support the drive towards net zero.

The fishing sector contributes to carbon emissions mainly through vessel emissions and use of refrigerants with additional impacts in the processing and wholesale sectors relating to transport of exports (Engelhard et al., 2022^[36]). A study of the Scottish pelagic fishing fleet showed 96% of emissions come from fuel use during fishing operations (Sandison et al., 2021^[37]).

The UK pelagic fleet is comprised of large, modern (and highly efficient) vessels. UK pelagic vessels are significantly larger and more technologically advanced than the rest of the Scottish vessels with an average length of 72 metres and an average engine power of 5800 kW, compared to an average length of fewer than 12 meters and an average engine power of 200 kW for the rest of the UK fishing fleet (Metz et al., 2022^[38]).

In Scotland, the pelagic fleet was made up of 21 vessels in 2024^[39] which represent only 1% of the Scottish fleet, but account for just over 50% of landings by value of all landings highlighting their disproportionate contribution to total catch. They target primarily North East Atlantic mackerel, North Sea herring, Atlantic herring (or ASH) and Blue Whiting in the North Sea and Atlantic Ocean. Unlike some fisheries which are operational year-round, pelagic targeting vessels tend to fish for only a small part of the year, meaning that days spent at sea is considerably less on average.

At UK level, fuel use from all fishing activity contributed an estimated 467 kt CO₂e in 2024—representing around 0.12% of total UK territorial emissions (378 Mt CO₂e) and 0.43% of domestic transport emissions (109 Mt CO₂e), and equivalent to about 1.1% of agricultural emissions (41.0 Mt CO₂e). The pelagic fleet has a high daily fuel demand with an annual fuel use of over 35,000 litres. This accounts to around 102 kt CO2e or around 17% of total emissions per fleet segment (Metz et al., 2022). Despite the relatively high fuel use of pelagic vessels, when emissions are assessed per unit of landed output (e.g. edible protein), pelagic species have high catch volumes relative to fuel use and, generally, have comparatively lower emissions than most other seafood (Sandison et al., 2021). In contrast, emissions intensity is typically higher in demersal trawl fisheries and some shellfish sectors, where fuel use per unit of catch is greater.

Long term considerations

Addressing many of the challenges associated with climate change are beyond the scope of the FMPs. The delivery of mitigation strategies for climate change is not within scope of this first iteration of these FMPs. The FMPs do, however, contain actions to explore options for adapting fishery management to challenges presented by the changing climatic conditions.

Climate change is transforming pelagic fisheries from relatively stable, predictable systems into highly dynamic, seasonally varying ones. While warming may create new fishing opportunities (particularly for some pelagic species in northern UK waters), it also increases biological uncertainty, spatial instability and geopolitical risk (Townhill et al., 2023; Garrett et al., 2024).

To support delivery of the climate change objective in the 2020 Act, the fisheries policy authorities will work in partnership with stakeholders to support fisheries in the drive to net zero and consider where and how we need to adapt our approaches to take account of the impacts of climate change.

The FMPs will be reviewed and revised as research into climate change impacts develops and new methods to address challenges from climate change become available.