West Coast of Scotland and Clyde Herring Fisheries Management Plan

Background

Stock

Herring is an important species in the West of Scotland, with WoS herring in particular forming a part of the overall pelagic fishery. Herring in Division 6.aN existed as a distinct management assessment unit from 1982 to 2014. Following the WKWEST benchmark meeting (ICES, 2015a), this stock was combined with herring in 6.aS 7.b-c, as the survey indices could not be successfully split between the two areas. From 2015 to 2021 the two stocks were assessed together as a meta-population (ICES, 2021b) despite continuing to be considered by Herring Assessment Working Group for the Area South of 62°N (HAWG) as discrete stocks.

Following recent genetic work (Farrell, et al., 2021, Farrell, et al., 2022), the survey indices have been successfully split, and the combined stock was separated back into its northern and southern components at the WKNSCS benchmark in 2022 (ICES, 2023a). The autumn spawning herring in 6.a North and the North Sea belong to the same genetic population but are assessed as two distinct stocks depending on their spatial distribution. Autumn spawning herring west of the 4° W line are assessed as 6.a North stock, whereas herring east of this are assessed within the North Sea autumn spawning (NSAS) stock. It should be noted that the 6aN spring spawning herring are not currently included in the 6aN stock assessment.

The herring fishery in the Clyde has declined from its peak in the 1960’s, with annual catches typically less than 500 tonnes over the last 20 years. Both WoS and Clyde herring are caught primarily by pelagic vessels. Excluding 180 tonnes caught in 2021 and 323 tonnes in 2025, there have been no commercial catches recorded in the Clyde since 2014.

Herring are demersal spawners, producing dense beds of benthic eggs on gravel substrates (often quite close inshore). This behaviour is considered to be an evolutionary remnant of herring’s river spawning past. Each female will produce a single batch of eggs per year, while the male will shed milt while swimming a few centimetres above the female. This reproductive behaviour makes herring vulnerable to anthropogenic activity such as offshore energy industries and gravel extraction.

Herring can reach 40 cm in length and have a maximum lifespan of 10 years, although most herring range between 20-30 cm and are less than seven years in age.

Herring constitute one of the highest biomasses of forage fish to the west of Scotland and Ireland and are thus an integral part of the ecosystem. As a dominant planktivore, herring link zooplankton production with higher trophic level predators, including fish, sea mammals and birds. Ecosystem models of the West of Scotland (Bailey et al., 2011; Alexander et al., 2015) show herring to be an important mid-trophic level species, along with sprat, sandeel, and horse mackerel. In The West of Scotland, the most important predators of herring are hake, mackerel, whiting, saithe, sharks, and minke whales, but they are present in the diets of many other piscivorous mammals, birds and commercially important fish (Serpetti et al., 2019). Herring can also predate on other fish species through consumption of fish eggs at certain times of year (ICES, 2014a). For example, work using length-based ecosystem modelling suggests a link between herring and cod biomass in the North Sea (Speirs et al., 2010), via the predation of cod eggs by herring.

As herring constitute an important part of the overall biomass of planktivorous and forage fish in the west of Scotland and Ireland ecosystem, impacts from changes in productivity from environmental drivers are likely to be widely felt.

The directed pelagic fishery for WoS herring is limited although in 2024 significant quantities of 6aN herring were caught as bycatch in the mackerel fishery. With regards Clyde herring, recent catches from the Clyde suggest it is largely a ‘clean’ fishery, meaning that there is little known bycatch of non-target fish species. The introduction of Remote Electronic Monitoring (REM) in Scottish waters will provide an enhanced level of confidence and ensure that effective tools are in place to deter and detect any illegal discarding.

Location

These stocks are found in International Council for the Exploration of the Sea (ICES) division 6.a North (West of Scotland). The Clyde herring stock is defined as the stock in the maritime area situated to the north-east of a line drawn between the Mull of Kintyre (55° 17,9′ N, 05° 47,8′ W), a point at position (55° 04′ N, 05° 23′ W), and Corsewall Point (55° 00,5′ N, 05° 09,4′ W). This FMP only applies to UK waters.

Fishery

Since 2016, WoS and Clyde herring landings have been limited to stock monitoring or bycatch from other fisheries. Catches of herring in the Clyde have typically been less than 500 tonnes over the past 20 years. Excluding the 180 tonnes caught in 2021 and 323 tonnes in 2025, there have been no significant landings of herring from the Clyde since 2014, with all other reported landings being from WoS.

The vast majority of WoS and Clyde herring is caught by pelagic targeting fleets. This segment of the fleet made up an average of 95% of landings between 2015 and 2024, and 100% of landings in 2023 and 2025.

Scottish-registered vessels making up 85% of all landings of WoS and Clyde herring caught by UK vessels between 2015 and 2024. English-registered vessels made up 11% of all landings, while Northern Irish vessels made the remaining 4%. All landings of WoS and Clyde herring were made by vessels using pelagic trawl gear.

As described above, WoS and Clyde herring landings are limited to being bycatch from other species, or stock monitoring. This means that the landings of WoS and Clyde herring are relatively unimportant overall for the fishing fleet, as these landings are approximately less than 1% of landings for all segments of the fleet, although herring is important to the small number of vessels that catch it WoS and Clyde herring landings are also unimportant for ports, being less than 1% of the total value of landings for the 12 ports where WoS and Clyde herring have been landed.