Herring or sild

Clupea harengus

Method of production — Caught at sea
Capture method — Pelagic trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Central Baltic Sea
Stock detail — 25-29 and 32 (excluding Gulf of Riga)
Picture of Herring or sild

Sustainability rating two info

Sustainability overview

The biomass for this stock was in decline but is now above sustainable levels, MSY Btrigger level, since 2006. Fishing mortality is currently below target and the stock harvested sustainably.

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

Stock Area

Central Baltic Sea

Stock information

The most important pelagic fish in the Baltic Sea fisheries are herring and sprat. Their distribution varies with season, food availability, hydrography etc. Herring occur throughout the Baltic Sea including the Gulf of Bothnia, Gulf of Finland and Gulf of Riga. Sprat are confined to areas south of the Aaland Islands and are mainly found in the open sea areas. Herring populations include both spring and autumn spawners. Previously, autumn spawning herring dominated the herring populations, but there was a change in the 1960s and since then spring spawning components have dominated the populations. Herring populations form a continuous chain extending from the North Sea to the northernmost parts of the Baltic Sea. In the western Baltic (Sub-divisions 22-24) the spring spawning stock of herring dominate. These herring spawn in the western Baltic Sea, but migrate to feeding areas in the Kattegat, Skagerrak and the eastern part of North Sea, where they mix with the North Sea herring. Both spring and autumn herring can be further divided into two population types - the sea and the coastal or Gulf herring. Within each population there are numerous sub-groups. Herring in the western Baltic (Sub-division 22-24) is assessed as one stock. Herring in the eastern Baltic is assessed as four stocks, i.e. herring in Sub-divisions 25-29 and 32, herring in the Gulf of Riga, herring in Sub-division 30 and herring in Sub-division 31. The herring in the central part of the Baltic Sea (Sub-divisions 25-29+32) is much the largest stock. The separation of stocks is a compromise between the large number of stocks/populations identified on a biological basis, and the ability to allocate catches to stocks. Also, management of the herring stocks are not possible on population by population basis.

Spawning-stock biomass (SSB) decreased until 2001 and then increased, and it has been above MSY Btrigger since 2006. Fishing mortality (F) increased until 2000 and then decreased, remaining below FMSY since 2004. Recruitment in 2015 is estimated to be the highest of the whole time-series.

Management

An EU Baltic Sea Multiannual Plan was established in 2016 for the management of herring stocks in the Central Baltic Sea.

Capture Information

In the Baltic, herring is mainly exploited in the open sea by pelagic trawls (single and pair trawls), and in coastal waters during spawning time, by trapnets, pound-nets and gillnets. Static nets in the Baltic are known to impact the harbour porpoise population, grey seals and a variety of diving waterbirds, and pelagic trawls can be associated with cetacean bycatch. The minimum landing size for herring in EU waters is 20cm (18cm in Skagerrak/Kattegat). Maturity is at around 17cm. As the fisheries in this area also take sprat, misreporting has been an issue; however, recent legislation has forced catches to be sorted before landing which is thought minimise the issue. The bycatch level of other species such as juvenile cod is unknown. Discarding of herring in the fishery is negligible.

References

ICES Advice 2017 http://ices.dk/sites/pub/Publication%20Reports/Advice/2017/2017/her.27.25-2932.pdf