Herring or sild

Clupea harengus

Method of production — Caught at sea
Capture method — Pelagic trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Irish Sea (South), Celtic Sea and southwest of Ireland
Stock detail — 7a (South), 7g, 7h, 7j, 7k
Picture of Herring or sild

Sustainability rating five info

Sustainability overview

Updated: July 2020.

Default red rating: ICES advices that there should be no fishing for herring in this area as the stock is depleted, below the level were reproductive abilities are likely to be impaired (Blim). Yet, a scientific fishery has been permitted in the absence of a recovery plan. As there is no precautionary recovery plan in place, although one is being developed, no fishing should be occurring.

Recent recruitment of young fish into the stock has been low, and average weight has been declining, which is a cause for concern. There is a management plan for this stock but it is no longer considered to be precautionary, and so a rebuilding plan is being developed. As well as catch limits, management includes closed areas that have reduced fishing mortality. There is little concern for bycatch or habitat impacts from this fishery. Scientific advice is to avoid negative impacts on the spawning habitat of herring, unless the effects of these activities have been assessed and shown not to be detrimental to the stock. There has been an increase in marine anthropogenic activity, especially in the area of marine renewables. The construction and development of wind farms, for example, results in disturbance to the seabed, as does aggregate extraction. Gravel is an essential habitat for spawning herring. The stock is below Blim (the level at which the stock’s ability to reproduce may be impaired) and there is no precautionary recover plan in place.

Biology

Herring belongs to the same family of fish (clupeids) as sprat and pilchard. It can grow to greater than 40 cm, although size differs between races (distinct breeding stocks). Most herring landed are around 25 cm. Herring are sexually mature at between 3-9 years (depending on stock) and populations include both spring and autumn spawners. At least one population in UK waters spawns in any one month of the year. Herring have an important role in the marine ecosystem, as a transformer of plankton at the bottom of the food chain to higher trophic or feeding levels, e.g. for cod, seabirds and marine mammals. It is also considered to have a major impact on other fish stocks as prey and predator and is itself prey for seabirds and marine mammals in the North Sea and other areas. Herring spawning and nursery areas are sensitive to anthropogenic or human influences such as sand and gravel extraction.

Stock information

Criterion score: Critical Fail info

The stock is at critical levels and the stock’s ability to reproduce is likely being impaired, fishing pressures have been significantly above sustainable limits in recent years.

The spawning-stock biomass (SSB) of herring within this area has significantly decreased, declining 84%, from 2011 (109,720 tonnes) to 2020 (17,485 tonnes). In 2018, SSB reduced to the lowest record level in the time series (6,463 tonnes), with records dating back to 1958 when SSB was at its greatest (212,881 tonnes). SSB has been below Blim (the level at which the stock’s ability to reproduce may be impaired) (34,000 tonnes) since 2016. In 2020, SSB increased ~49% from the previous year, possibly owing to reducing fishing mortality and the stronger year-class of 2019. In 2020, the ratio of B:BMSY was 0.32. Fishing mortality (F) increased in 2008 and began to reduce in 2017, with catches in 2020 being limited by a scientific monitoring Total Allowable Catch (TAC). However, F (0.49) remains above the maximum sustainable yield (FMSY) (0.26), and the upper limit of F for fishing mortality to remain stable (Flim) (0.45). In 2019, the ratio of F:FMSY was 1.9. Recruitment (R) has been below average since 2013, and in 2020 R was the lowest it has been in the time-series (1958-2020), which is a significant cause for concern.

ICES advises that when the MSY approach is applied, there should be zero catch in 2021. Advice has not changed from the zero catch advice for 2020. This is because there are no catch scenarios that will rebuild the stock above Blim (34,000 tonnes) by 2022. As the stock is below Blim this results in a default red-rating.

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 way to 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.

The concurrent declines in mean weights of herring in catches, is a cause for concern, because of their impact on yield and yield per recruit. This is thought to be mostly driven by environmental factors i.e. rising sea temperature, in addition to local factors, such as changes in salinity and trophic and fishery related indicators.

Recruitment estimates are uncertain, due to a lack of recruitment indices. In the Irish Sea, mixing occurs between Celtic Sea and Irish Sea fish, but the level of mixing is unknown. Division 7h is part of the management area, but it is unclear if it is part of the stock.

Management

There is no precautionary management plan or recovery plan in place for this fishery. The stock is significantly decreasing and at critically low levels, with catches continuing against scientific advice.

ICES advises that when the precautionary approach is applied, there should be zero catch in 2021. However, a scientific fishery is in place and there is a monitoring Total Allowable Catch (TAC) in place. Assignment of a TAC when there is zero catch advice results in a default red-rating.

A long-term management strategy for Celtic Sea herring, which was proposed by the Pelagic AC in 2011, came into force in 2012. However, this management strategy was re-evaluated by ICES in 2018 at the request of the European Union. ICES advises that the harvest control rule is no longer consistent with the precautionary approach: there is a greater than 5% probability of the stock falling below Blim. Subsequently, a rebuilding plan is currently being developed for this stock.

This fishery was managed by an annual TAC limit up until 2019, for commercial catch. Between 2015-2019, TACs were set on average 9% above advice, during this period annual TACs were set; close to; significantly below; and significantly above, scientific advice. In 2019, the TAC was set in line with advice. On average catches were significantly below the maximum advised catch level and the TAC, between 2015-2019. Therefore, recent annual catch advice and TAC limits have not limited fishing mortality. In 2019, the European Commission requested ICES to advise on the minimum level of catches (tonnages) required in a sentinel TAC, which would provide sufficient data for ICES in order to continue providing scientific advice on the state of the stock. ICES advised that at least 17 samples from the main and the sentinel fleet would be required to provide advice on similar bases as with a commercial fishery. ICES advised that those samples could be obtained through a monitoring catch of 869 tonnes in 2020. As a result, a TAC of 869 tonnes for 2020 was agreed by the Council of the European Union, despite ICES zero catch advice.

Discards are considered to be negligible; between 1% (2015-2017) and 0% (2018-2019).

As well as catch limits, management includes closed areas, that has reduced fishing mortality. The southern Irish Sea, Division 7a South, has been closed to most fishing vessels since 2007, except small, dry-hold vessels, up to 50 feet in length. It was intended to protect first-time spawners and has a maximum quota allocation of 11%. It does appear to have reduced fishing mortality.

In recent years Ireland has been the main participant in this fishery with other countries reporting small catches annually. This fishery is managed by the Irish Celtic Sea Herring Management Advisory Committee, established in 2000 and constituted in law in 2005. The Irish quota is managed by some fishing constraints; fishing is restricted to the period Monday to Friday each week; and vessels must apply a week in advance before they are allowed to fish in the following week. Triennial spawning box closures are enshrined in EU legislation. The large number of vessels involved has led to individual vessel quotas being reduced, which initially led to increased discarding risk due to vessels being unable to catch their small allocations without extra-quota catches that are often slipped (meaning fish are allowed to swim out of nets after being caught). However, in 2012, flexibility was introduced to the system, whereby a vessel could use some of the following week’s quota to mitigate slippage.

It is known that juvenile Celtic Sea herring mix with the Irish Sea stock, which could have implications for management and advice.

Scientific advice is to avoid negative impacts on the spawning habitat of herring, unless the effects of these activities have been assessed and shown not to be detrimental to the stock. There has been an increase in marine anthropogenic activity, especially in the area of marine renewables. The construction and development of wind farms, for example, results in disturbance to the seabed, as does aggregate extraction. Gravel is an essential habitat for spawning herring.

Beyond the monitoring TAC, harvesting of herring is controlled through an EU Minimum Landing Size (MLS) of 20cm which is above herring size of maturity at around 17cm, however the majority of catch was reported <20cm in 2019.


The UK is due to leave the EU on 31st December 2020, and new UK Fisheries legislation is being developed during 2020. MCS will update ratings with new management information when new legislation comes into force.

In the European Union (EU), EU fishing vessels can fish up to 12 nautical miles of any Member State coast, and closer by agreement. There is overarching fisheries legislation for all Member States, but implementation varies between fisheries, Member States and sea basins.
The EU Common Fisheries Policy (CFP) is the primary overarching policy. Its key environmental objectives are to restore and maintain harvested species at healthy levels (above BMSY), and apply the precautionary and ecosystem-based approaches to fisheries management. To achieve the MSY objective, the MSY exploitation rate is supposed to be achieved by 2020, but this seems unlikely to happen.
The CFP also introduced a Landing Obligation (LO) which bans the discarding at sea of species which are subject to catch limits. Some exemptions apply to species with high post-capture survival, and where avoiding unwanted catches is very difficult. These exemptions are outlined in regional discard plans. Despite quota ‘uplift’ being granted to fleets under the LO, available evidence suggests there has been widespread non-compliance with the policy, and illegal and unreported discarding is likely occurring.
Multi-Annual Plans (MAPs) are a tool for implementing the CFP regionally, with one in place or being developed for each sea basin. They specify fishing mortality targets and ranges for the main targeted species, as well as lower biomass reference points. If populations drop below these points it should trigger a management response. The MAPs also empower Member States to jointly apply measures such as closures, gear or capacity limits, and bycatch limits. There is concern however that the MAPs do not provide adequate safeguards to maintain all stocks at healthy levels.
The EU Technical Measures regulation addresses how, where and when fishing can take place in order to limit unwanted catches and ecosystem impacts. There are common measures that apply to all EU sea basins, and regional measures that vary between sea basins. Measures include Minimum Conservation Reference Sizes (MCRS, previously Minimum Landing Sizes, MLS), gear specifications, mesh sizes, closed areas, and bycatch limits.
The Control Regulation, which is being revised in 2019, addresses application of and compliance with the above, e.g. keeping catches within limits, recording and sharing data, and satellite tracking of vessels over 12 metres (VMS).

Capture Information

Herring are caught by pelagic trawls in the Irish Sea (South), Celtic Sea and southwest of Ireland.

Herring fisheries are well targeted and tend to be clean with little bycatch of other fish.

Ireland is the main participant in the herring fishery within the Celtic Sea, with other countries (UK, Belgium, The Netherlands, Germany and France) now reporting little to no catch. Since 2011, fishing has taken place in the second half of the year (mainly in quarter four and to a lesser extent in quarter three), herring are found to be more abundant when the water is cooler. The fishery takes 100% of herring catch by pelagic trawlers, drift netters used to participate but catch is now deemed to be negligible. The stock is exploited by larger boats with refrigerated storage, and some smaller dry hold vessels. The smaller vessels are confined to the spawning grounds (Divisions 7a South and 7g) during the winter period. The larger vessels target the stock inshore in winter and offshore during the summer feeding phase (Division 7g). There has been less fishing in Division 7j in recent seasons. The fishery is now divided in two fleets, the main human consumption fleet and the sentinel (scientific monitoring) fleet.

In recent years herring have been frequently distributed close to the bottom, making it more difficult for fishermen to detect them with the acoustic sounders, particularly offshore. The fishery in 2018 was mainly concentrated inshore (Division 7g) with no significant offshore fishery, and Irish vessels had difficulty in catching their quota. In 2019, the high provenance of fish below the minimum conservation reference size of 20cm, prevented the main fleet fishing more than 5 days and catching their quota.

The pelagic fisheries on herring are deemed to be some of the cleanest fisheries in terms of bycatch, disturbance of the seabed and discarding. Pelagic trawling is a well-targeted method and most boats are equipped with sonar and net and catch monitors, catching herring through acoustic detection with a very low risk of marine mammal bycatch. Pelagic trawls can be associated with bycatch of marine mammals, but, there have been few documented reports of bycatch of Endangered, Threatened or Protected (ETP) species within this fishery. Interactions with ETP species is considered to be low within this fishery. Anecdotal reports suggest seals (including grey), blue sharks, tunas, and whitefish are caught from time to time, but it is unlikely that the rate of incidental catch in the Celtic Sea would cause species to decline. In the 2017 observer study of the Celtic Sea herring fishery, no marine mammals or seabirds were recorded as bycatch in the fishery. Incidental catch of other non-target species (bycatch) is thought to be low. Where incidental catch does occur species may include whiting, haddock, mackerel or gurnard. The pelagic herring fishery in the Celtic Sea, has little to no impact upon the seabed, as there is no contact with the seabed, and therefore no risk to habitats.

Herring are an important component of the Celtic sea ecosystem, as an important prey species and also one of the dominant planktivorous fish. A potential impact of the herring fishery is the removal of fish that could provide other ecosystem services. Herring are an important source of food for marine mammal predators such as fin whales (Balaenoptera physalus). Cetaceans are also important predators of herring in this area, and a preliminary estimate of annual consumption of herring by cetaceans is 3,300 tonnes. Herring form part of the food source for larger gadoids such as hake in the Celtic Sea.

Herring spawn close to the coast, and deposit their eggs on gravel or flat stone. Gravel extraction is therefore a threat to the stock.

Research suggests that herring recruitment is better in cooler temperatures, so any increase in sea surface temperature could have negative impacts on the stock.

References

Benchmark Workshop on West of Scotland Herring (WKWEST) (2015). Stock Annex: Herring (Clupea harengus) in divisions 7.a South of 52degrees 30’N, 7.g–h, and 7.j–k (Irish Sea, Celtic Sea, and southwest of Ireland). Available at https://www.ices.dk/sites/pub/Publication%20Reports/Stock%20Annexes/2015/her-irls_SA.pdf [Accessed 08.07.2020]

Binohlan, C. and Nicolas, B. (Editors) (2020). Atlantic herring (Clupea harengus). Available at https://www.fishbase.se/summary/Clupea-harengus.html [Accessed 06.07.2020]

EC (1983). COUNCIL REGULATION (EEC) No 2931/83 of 4 October 1983 amending Regulation (EEC) No 171 /83 laying down certain technical measures for the conservation of fishery resources. Available at https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:31983R2931&from=EL [Accessed 18.06.2020]

Pelagic AC (2011). Long-term management plan for herring in the Celtic Sea and Division VIIj, as agreed by the Pelagic Regional Advisory Council. Available at www.pelagic-ac.org/media/pdf/LTMP%20Celtic%20Sea%20and%20South%20of%20Ireland%20herring.pdf [Accessed 08.07.2020]

ICES (2020). Herring Assessment Working Group for the Area South of 62degrees N (HAWG). ICES Scientific Reports, 2:60. 1054 pp. Available at http://www.ices.dk/sites/pub/Publication%20Reports/Expert%20Group%20Report/Fisheries%20Resources%20Steering%20Group/2020/HAWG/01%20HAWG%20Report%202020.pdf [Accessed 06.07.2020]

ICES (2020). Herring (Clupea harengus) in divisions 7.a South of 52degrees 30’N, 7.g–h, and 7.j–k (Irish Sea, Celtic Sea, and southwest of Ireland). In Report of the ICES Advisory Committee, 2020. ICES Advice 2020, her.27.irls. https://doi.org/10.17895/ices.advice.5944. Available at http://ices.dk/sites/pub/Publication%20Reports/Advice/2020/2020/her.27.irls.pdf [Accessed 08.07.2020]