Herring in the northern Irish Sea is overfished and subject to overfishing.Stock assessments are carried out annually by the International Council for the Exploration of the Sea (ICES). The most recent assessment was published in 2025 using data up to the same year. 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.In 2024 a serious issue with the assessment was identified, which resulted in an inter-benchmark and led to the 2023 advice for 2024 being re-issued.The spawning stock biomass (SSB) of herring in this area recovered from a low of around 7,512 tonnes in 2003 to 29,086t in 2010 and has fluctuated at high levels since. In 2025, the forecasted SSB was 9,358 tonnes, which is below MSY Btrigger (11,793 tonnes) and the GFG proxy for Bpa (9,573 tonnes), but above Blim (Blim: 7,352t). Therefore, there is concern for the stock level.Fishing mortality (F) has been increasing in recent years. In 2024, F (0.505) was above levels associated with Maximum Sustainable Yield (FMSY = 0.25) and Flim (0.45). Therefore, this stock is outside safe fishing limits and being overfished.Recruitment has fluctuated around the 10-year average since 2012, with a high recruitment in 2022 of 274,797 tonnes, but a lower recruitment of 173,916t in 2024.ICES advises that when the MSY approach is applies catches of herring in the Irish Sea should be no more than 2,935 tonnes in 2026. This fishery included herring from the Celtic sea stock which are below Blim and are set to have zero catch.
Marine Stewardship Council (MSC)
