Blue mussel

The status of blue mussel stocks in the Northeast Atlantic is poor. The species grows relatively slowly, can reach an advanced age and is therefore sensitive to intensive fishing. Due to the limited movement of mussels, mussel beds can deteriorate or disappear for long periods when overfished. In several parts of the species’ range, mussel beds have declined in recent years.

Fishing with mussel dredges has little bycatch of vulnerable (ETP) species. However, bottom-dwelling animals, corals and other reef-forming organisms are regularly caught as bycatch. Discards are insufficiently documented, but data from MSC-certified fisheries show that less than 10% of the catch consists of unmanaged or overfished species. Mussel dredges cause very significant damage to the seabed and the organisms living there. This can cause the structure of mussel beds to disappear and disrupt the food web for long periods. CO₂ emissions from this fishery are moderate. Lost mussel dredges pose little risk of ghost fishing because they are heavy and remain on the seabed.

Management is considered partially effective. Monitoring varies considerably by region: a lot of data are available for MSC-certified fisheries, but in large parts of the species’ range, up-to-date data on the size and distribution of mussel beds are lacking. In the European Union and the United Kingdom, measures are in place to limit fishing pressure and damage to vulnerable habitats, including closed areas and nature protection measures. Nevertheless, mussel beds in Scotland and Sweden, among others, continue to decline, and they have disappeared in parts of France. There are no Fishery Improvement Projects (FIPs) for this fishery. Within FAO Area 27, five fisheries are MSC-certified.

The status of blue mussel stocks in the Danish Limfjord is moderate. Biomass has declined sharply in recent years and there is an increased risk that the reproductive capacity of the stock will be affected. Fishing pressure is adjusted to the size of the stock and takes the food requirements of birds into account, thereby helping to prevent overfishing as much as possible.

Fishing with mussel dredges has no significant bycatch of vulnerable (ETP) species. Discards are low and less than 5% of the catch is discarded. However, starfish, shore crabs and oysters, among others, are also caught. Mussel dredges cause significant damage to the seabed and can alter the food web and seabed structure for long periods. CO₂ emissions and the risk of ghost fishing are low.

Management is considered partially effective. Stocks are regularly monitored and measures are in place to limit fishing pressure, but it is uncertain whether these are sufficient to achieve the recovery of mussel beds. There is also criticism of enforcement of the rules governing fishing in the Limfjord. The fishery is MSC-certified.

Much of the mussels grown in Europe are MSC(EN) MSC:
Marine Stewardship Council, an independent, international non-profit organization that has developed an eco-label that guarantees well-managed, sustainable fisheries. Fish products that meet the criteria of the eco-label can be identified by the blue MSC logo.-certified. In mussel farming, the mussel seedMussel seed:
Mussel larvae. is fished from the wild and then reared into consumer mussels. The fishing of mussel seed is done with dredges or with mussel seed capture devices (MZIMZI:
Mussel seed capture system, or 'mosselzaadvanginstallatie' in Dutch (MZI), is a specialized system used to caputre mussel seed from the watercolumn. The systems use ropes hanging in the water colum on which mussels seed attach. The ropes are attached to an anker below and floating devices above.s). Under MSC certification, fishing of mussel seed with MZIs is further encouraged. MSC-certified mussels are grown in bottomBottom trawls:
A fishing technique in which cone-shaped nets terminating in a codend are dragged through the water column or along the bottom. culture and ropeRope culture:
Culturing schellfish on poles and/or wire nets that are hanging in the water column. Using feed from the sea water, mussels and other shellfish grow up to consumption size.   culture.

MSC mussels from other countries have been allowed to be diluted in the Netherlands since 2016 and then sold as Dutch MSC mussels. Dutch mussels largely come from bottom culture in the Oosterschelde and Grevelingen Lake.

The farming of blue mussels is performing fairly well. Mussels are farmed on ropes, on poles, on the seabed or on rafts in marine and coastal waters. Because mussels feed on plankton from the water, no feed or fertilisers are required and the environmental impact of farming is generally low.

Farming produces very little waste and can even contribute to removing nutrients from the water. Depending on the production method, mussel plots can have both positive and negative effects on the seabed and benthic life. Bottom culture in particular can disturb the seabed. Diseases and parasites occur, but large-scale outbreaks are rare. Escaped mussels generally have little impact on the environment because they are a native species.

Mussel seed is usually collected from natural mussel beds, including with mussel dredges, and in some areas using specialised collection installations. Collection using these installations has little impact on the surrounding environment. Harvesting mussel seed with mussel dredges causes greater disturbance to the seabed and vulnerable habitats and is not recommended by Good Fish.

Management differs between countries but is generally considered largely effective. Aquaculture Improvement Programs (AIPs) are not available for some countries. In addition, various farms have sustainability certifications, such as ASC, organic certification or other independent certifications.

The latest assessment of this fishery was in 2017.

It is unclear how the stocks of blue mussel in the Norwegian Exclusive Economic Zone are doing. Data on catches and stock size are lacking, making it difficult to properly assess their status.

Hand collection has virtually no bycatch of vulnerable (ETP) species. Discards are also negligible. This small-scale fishery causes little damage to the seabed and there is no indication that the ecosystem is adversely affected.

Management is considered partially effective. Specific management measures for the wild mussel fishery are scarcely described; the available information mainly concerns mussel farming.