Genetic Scorecard Indicator - Atlantic Herring
Atlantic Herring (Clupea harengus)
IUCN Category:
- Great Britain: Not assessed (indicated above)
- Europe: Least concern
- Global: Least concern
Genetic Health Status:
- Scottish Risk: Negligible (indicated above)
- UK Risk: Negligible
- Scottish Mitigation status: Not required
- UK Mitigation status: Not required
Background
Atlantic herring is an abundant, ecologically and economically important schooling pelagic fish that occurs on the marine continental shelf down to 200m. The species has a broad North Atlantic distribution and is managed as multiple stocks that spawn in different locations and/or at different times. Herring from different spawning areas often aggregate in the same nursery, feeding, and wintering areas but commonly return to their natal site to reproduce (Ellis et al., 2012; ICES 2022). Several large population fluctuations have occurred since the mid-20th century, and there have been associated shifts in the spatial and temporal patterns of spawning (Han et al., 2020; Frost & Diele, 2022). Historically, these populations appear to have been stable, and these recent fluctuations are attributed to both environmental variation and fishing pressure (Altmore et al., 2024).
Whole genome sequence data indicate that herring spawning around the UK and Ireland are genetically distinct from those spawning in other locations and exhibit locally adaptive loci (Han et al., 2020). UK herring can be further split into at least five genetically differentiated groups, reflecting location and timing of spawning (Farrell et al., 2022; Altmore et al., 2024; Seljestad et al., 2024). Genetic characterization of UK-spawning herring is incomplete and other distinct subpopulations may exist (Dicky-Collas et al., 2010). Current herring fisheries stock definitions/ management units do not completely correspond to the known genetic divisions; and fisheries catches often contain a mixture of different genetic groups, including those spawning in non-UK waters (Farrell et al., 2022; Seljestad et al., 2024).
Current Threats
Past over-harvest has contributed to population crashes. Although there are limits on total allowable catches (TAC) for Herring fisheries exploiting UK stocks, there is uncertainty in TAC estimates, and fisheries quotas can be higher than recommended TACs (Froese et al., 2025). Additionally, TACs are created based on current stock definitions leading to single combined TACs for the genetically distinct populations. Herring are also caught as by-catch in other fisheries.
Spawning beds are vulnerable to anthropogenic impacts, particularly gravel extraction and development of offshore energy infrastructure such as wind farms (Frost & Diele, 2022). The location of many spawning areas is unknown, which limits their protection. Eggs are also vulnerable to local acute impacts including pollution, storm damage, and bottom trawling.
Climate change is expected to impact herring stocks and has been implicated in recent low recruitment although high effective population sizes and standing genetic variation may allow adaptation (Andersson et al., 2023)
Contribution of Scottish/UK population to total species diversity
The British Isles support internationally important breeding populations of herring that are genetically distinct from those spawning elsewhere (Han et al., 2020).
Genetic risks
Diversity loss: population declines
Very large long-term population sizes are likely to buffer Atlantic herring against genetic diversity loss even in the face of large population reductions. Mariani et al. (2005) did not observe any effects of mid-20th-century herring population crashes on genetic diversity. However, Altmore et al. (2024) associated these crashes with a 20% reduction in Ne and suggested that long-term fishery exploitation had caused some genetic diversity loss.
Global Biodiversity Framework Indicators
Population definitions:
The proportion of populations spawning in UK waters were defined by genetic clusters as identified by Han et al (2020), Farrell et al. (2022) and Seljestad et al. (2024):
Ne500: The proportion of populations that have an effective population size of more than 500.
- Proportion of populations with Ne > 500 in Scotland = 2/2
- Proportion of populations with Ne > 500 in UK = 5/5
PM: Proportion of populations that existed in 2000 that still exist in 2025:
- Proportion of populations maintained Scotland = 2/2
- Proportion of populations maintained in UK = 5/5
Diversity loss: functional variation
Functional variation
Herring populations are known to be genetically adapted to local conditions and also exhibit genetically based life-history diversity in terms of spawning location and time (Spring vs. Autumn-Winter). Spring spawning herring in the UK have undergone large population declines and are poorly characterized and monitored – thus, there is a potential risk to this stock component.
Divergent lineages
Several genetically distinct populations exist but none are known to be at risk of loss.
Hybridisation/Introgression
No known risk.
Low turnover - constraints on adaptive opportunities
No known risk.
Cumulative Risk Summary
Overall Genetic Health Status
Scotland
- Risk: Negligible
- Mitigation: Not required
Great Britain/UK
- Risk: Negligible
- Mitigation: Not required
In situ genetic threat level
In situ genetic threat level
- In situ Risk for Scotland: Negligible
- In situ Risk for UK: Negligible
Very large long-term effective population sizes for most populations are expected to buffer risk.
Confidence in in situ threat level
- Confidence score for Scotland: Medium
- Confidence score for UK: Medium
Population genetic structure of UK spawning herring is not completely characterised, and some smaller genetically distinct stocks may be at higher risk.
Ex situ representation
There are no ex-situ populations.
Current conservation actions
No conservation actions.
| Ex situ | Translocation | Habitat management | Legal protection of habitat or species | Regulation of exploitation | Control of INNS/pests/pathogens |
|---|---|---|---|---|---|
| - | - | - | - | - | - |
Population assessment/monitoring
Population
Demographic
Annual stock size monitoring.
N pops assessed/monitored in Scotland = 2/2
N pops assessed/monitored in UK = 4/5
Genetic
Genetic stock identification used annually as part of stock monitoring, ongoing population genetic research.
N pops assessed/monitored in Scotland = 2/2
N pops assessed/monitored in UK = 4/5
References
Andersson, L., André, C., Johannesson, K., Pettersson, M., (2023) Ecological adaptation in cod and herring and possible consequences of future climate change in the Baltic Sea. Front. Mar. Sci. 10.
Atmore, L.M., van der Jagt, I., Boilard, A., Häberle, S., Blevis, R., Dierickx, K., Quinlan, L.M., Orton, D.C., Hufthammer, A.K., Barrett, J.H., Star, B., (2024) The Once and Future Fish: Assessing a Millennium of Atlantic Herring Exploitation Through Mixed-Stock Analysis and Ancient DNA. Glob Chang Biol. 30:e70010.
Dickey-Collas M, Nash RDM, Brunel T, van Damme CJG, Marshall CT, Payne MR, Corten A, Geffen AJ, Peck MA, Hatfield EMC, Hintzen NT, Enberg K, Kell LT, Simmonds EJ (2010) Lessons learned from stock collapse and recovery of North Sea herring: a review, ICES Journal of Marine Science, 67: 1875–1886.
Ellis, J.R., Milligan, S.P., Readdy, L., Taylor, N. and Brown, M.J. 2012. Spawning and nursery grounds of selected fish species in UK waters. Sci. Ser. Tech. Rep., Cefas Lowestoft, 147: 56pp.
Farrell, E.D. et al., 2022 A baseline for the genetic stock identification of Atlantic herring, Clupea harengus, in ICES Divisions 6.a, 7.b–c. R. Soc. Open Sci. 9: 220453
Frost, M., Diele, K., (2022) Essential spawning grounds of Scottish herring: current knowledge and future challenges. Rev Fish Biol Fisheries 32, 721–744
Han F, Jamsandekar M, Pettersson ME, Su L, Fuentes-Pardo AP, Davis BW, Bekkevold D, Berg F, Casini M, Dahle G, Farrell ED, Folkvord A, Andersson L (2020) Ecological adaptation in Atlantic herring is associated with large shifts in allele frequencies at hundreds of loci eLife 9:e61076.
ICES (2022) Stock Annex: Herring (Clupea harengus) in division 6.aN (West of Scotland). ICES Stock Annexes. 18 pp.
ICES (2023) Benchmark Workshop on North Sea and Celtic Sea stocks (WKNSCS). ICES Scientific Reports. 5:04. 324 pp.
ICES (2025) Herring Assessment Working Group for the Area South of 62° North (HAWG). ICES Scientific Reports. 7:20.
Mariani S, Hutchinson WF, Hatfield EMC, Ruzzante DE, Simmonds EJ, Dahlgren TG, Andre C, Brigham J, Torstensen E, Carvalho GR (2005) North Sea herring population structure revealed by microsatellite analysis. Mar Ecol Prog Ser 303:245-257
Rybicki S, Hamon KG, Simons S, Temming A (2020) To Fish or Not to Fish – Economic Perspectives of the Pelagic Northeast Atlantic Mackerel and Herring Fishery. Front. Mar. Sci. 7.
Seljestad GW, Quintela M, Bekkevold D, Pampoulie C, Farrell ED, Kvamme C, Slotte A, Dahle G, Sørvik AG, Pettersson ME, Andersson L, Folkvord A, Glover KA, Berg F. (2024) Genetic Stock Identification Reveals Mismatches Between Management Areas and Population Genetic Structure in a Migratory Pelagic Fish. Evol Appl. 17:e70030.
Assessor: Victoria Pritchard, UHI Inverness.
Reviewer: Linda Neaves, Murdoch University.
