The ICES herring assessment working group (HAWG) met in Aberdeen, Scotland from 12-21 March 2024 to assess the state of six herring (Clupea harengus) and one sprat (Sprattus sprattus) stock. Additionally, HAWG provided advice for eight Sandeel (Ammodytes spp.) in January 2023. The working group conducted update category 1 assessments for four of the herring stocks and category 3 assessments for 2 herring stocks. An analytical assessment was performed for the combined North Sea and Division 3.a sprat, and data limited assessment (ICES category 3) was conducted for English Channel sprat (spr.27.7de). Biennial advice is given for sprat in the Celtic Seas and West of Scotland with advice provided in 2023.
North Sea autumn spawning herring (her.27.3a47d). SSB in 2023 was estimated at 1.52 million tonnes while F2–6 in 2023 was estimated at 0.23, which is below FMSY. Recruitment is at a stable level, which is expected to contribute positively to SSB levels from 2024 onwards. ICES considers that the stock is still in a low productivity phase.
Western Baltic spring-spawning herring (her.27.20-24). SSB in 2023 was estimated at 66,152 tonnes and is below MSY Btrigger, Bpa, and Blim. Recruitment has been low since 2007 and has been deteriorating further with time. F3-6 has been decreasing since 2018 and is now well below FMSY (0.31) at 0.053. The stock has decreased consistently during the second half of the 2000s and given the continued low recruitment, the stock is not able to recover above Blim unless a drastic reduc-tion in fishing effort is applied for several years.
Celtic Sea autumn and winter spawning stock (her.27.irls). SSB in 2023 was estimated at 15,157 tonnes, though is increasing from its lowest level seen in 2018 (6,474 tonnes), but remains below Blim (34,000 tonnes). F(2-5 rings) in 2022 was estimated at 0.058, having decreased from a peak of 1.16 in 2017. Recruitment has been consistently below average since 2013.
Irish Sea autumn spawning herring (her.27.nirs). SSB in 2023 was estimated at 91350 tonnes and is above MSY Btrigger, Bpa, and Blim. Recruitment in 2023 is slightly below the 2022 recruit-ment, which was the highest on record. The trend of large incoming year-classes in recent years continues. F4-6 is estimated at 0.49 which is slightly above FMSY (0.35). The assessment model of her.27.nirs was changed in 2024 due to issues with the old model.
6aN autumn spawning herring (her.27.6aN). SSB in 2023 was estimated at 22,463 tonnes using the genetically split, Malin Shelf Herring Acoustic Survey (MSHAS). Whilst SSB has increased since its lowest level in 2019. Indicators show that stock size is above Itrigger and harvest rate below HRMSY proxy (0.28).
Herring in 6.aS/7.b, c (her.27.6aS7bc). SSB in 2023 was estimated at 100,523 tonnes using the genetically split, Malin Shelf Herring Acoustic Survey (MSHAS) and has been increasing since the lowest point in 2016 (36,707 t). Recent catches are among the lowest in the time series. Fishing pressure on the stock is below HRMSY proxy (0.26) and the stock size index is well above Itrigger (51 390 t).
Sprat in the North Sea and 3.a (spr.27.3a4). SSB in 2024 was estimated at 83,754 tonnes and is below MSY Bescapement, Bpa, and Blim. F1-2 has been decreasing since 2016, but was estimated at a high level in 2024. There are high levels of fluctuations in F throughout the time series. Low recruitment in recent years had contributed to the stock being below MSY Bescapement.
Sprat in the English Channel (spr.27.7de). Biomass in 2023 was estimated at 61 270 tonnes using the Pelagic Ecosystem Survey in the Western Channel and Celtic Sea (PELTIC). The catch advice applies a constant harvest rate (CHR) of 8.57% to the survey biomass. Fishing pressure is below FMSY proxy with stock size above MSY Btrigger (Istat).
Sprat in the Celtic Seas and West of Scotland (spr.27.67a-cf-k). Catch advice was given for 2024 and 2025 using the ICES Category 5 method where only landings data are available. The precau-tionary buffer (20% reduction) was applied in 2021, and thus was not applied in this advice year.
Sandeel in Divisions 4b–c (Sandeel area 1r). SSB in 2023 was estimated at 159,384 tonnes and is above MSY Bescapement, Bpa, and Blim. Although recruitment has been below average between 2020–2023, it has been slowly increasing and has allowed a fishery in 2024. F1-2 is estimated at 0.26, which is below Fcap of 0.36.
Sandeel in Divisions4b–c (Sandeel area 2r). SSB in 2023 was estimated at 44,234 tonnes and is above MSY Bescapement , Bpa and Blim. Recruitment in 2023 is one of the lowest recruitment years on record. F1-2 (0.43) is below Fcap (0.52).
Sandeel in Divisions 4a–b and Subdivision 20 (Sandeel area 3r). SSB in 2023 was estimated at 247,285 tonnes and is above MSY Bescapement, Bpa, and Blim. Recruitment in 2023 has been continu-ously decreasing the last three years, and is nearing one of the lowest observed years, leading to the only catch opportunities being a monitoring quota. F1-2 is estimated at 0.13, which is lower than Fcap of 0.47.
Sandeel in Divisions 4a–b (Sandeel area 4). SSB in 2023 was estimated at 81,750 tonnes and is below MSY Bescapement and between Bpa and Blim. Recruitment in 2022 is higher than that in 2021. F1-2 has decreased since the previous year.
Sandeel in Division 4a (Sandeel area 5r). Catch advice was given for 2023 and 2024 using the ICES Category 5 method where only catch data are available. The precautionary buffer (20% reduction) was applied in 2021, and thus was not applied in this advice year.
Sandeel in Subdivisions 20–22 (Sandeel area 6). Catch advice was given for 2023 and 2024 using the ICES Category 5 method where only catch data are available. The precautionary buffer (20% reduction) was applied in 2021, and thus was not applied in this advice year.
Sandeel in Division 4a (Sandeel area 7r). Catch advice was given for 2023 and 2024 using the ICES Category 5 method where only catch data are available. The precautionary buffer (20% reduction) was applied in 2021, and thus was not applied in this advice year.
Sandeel in Division 6a. Zero catch advice was given for 2024, 2025, 2026 following the ICES Category 6 method.
Standard issues such as benchmark planning, the quality and availability of data, availability of data through industry surveys and scientific advances particularly with respect to the use of genetics for stock discrimination were discussed.
All data and scripts used to perform the assessments and the forecast calculations are available at https://github.com/ICES-dk/wg_HAWG and accessible to anyone.