Latin name – Mytilus edulis (blue mussel)
Taxonomic Code: 3161000105
Production (EU-27) – 175 934 t (2007); 86 % of global production
Value (EU-27) – EUR 231 million (2007)
Main EU producer countries – France, Netherlands, Ireland, United Kingdom
Main producer countries worldwide – Idem
Latin name – Mytilus galloprovincialis (Mediterranean mussel)
Taxonomic Code: 3161000112
Production (EU-27) – 306 934 t (2007). Value (EU-27) – EUR 86 265 000 (2006)
Main EU producer countries – Spain, Italy
Main producer countries worldwide – Idem.

Local Names
Arabic : Tamr el bahr
Catalan : Clòtxina,  Musclo
English : Bay mussel,  Black mussel,  Blue mussel,  Common mussel,  Edible mussel,  Mussel
French : Moule,  Moule commune
German : Miesmuschel
Greek : Mýdi
Hebrew : Zidpit galit
Italian : Mitilo
Serbo-Croat : Dagnja
Spanish : Mejillón
Turkish : Midye

Diagnostic Features

Shell solid, equivalve; inequilateral, beaks at the anterior end; approximately triangular in outline. Hinge line without teeth but with 3 to 12 small crenulations, under the umbones. Margin smooth. Pallial line wide; anterior adductor scar very small, posterior large. External ligament much concealed, extending more than half-way from the beaks to the highest point of the shell. Sculpture of fine concentric lines.  Colour purple, blue, sometimes brown, occasionally with prominent dark brown to purple radial markings. Periostracum almost black, dark brown, or olive; interior pearl-white with a wide border of purple or dark blue. 

Habitat and Biology

The exact range of M. edulis is not known because of the confusion with other, very similar Mytilus. In Europe it lives on all coasts that have hard substrates.Intertidal to 40 m deep attached by byssus threads to rocks and piers, within sheltered harbors and estuaries and on rocky shores of the open coast, sometimes living in dense masses wherever there are suitable surfaces for attachment.The diet of mussels consists of phytoplankton and detritus filtered from the surrounding water.The dimensions of the species is greatly influenced by its biotope: intertidal shells often remain small, rarely exceeding 6 cm, while deep-water shells easily measure 9 cm. 

Market And Trade

Europe has traditionally been a high-value market, with prices in 2,000 ranging from USD 1,700/tons in the U.K. to USD 1,200 - 1,550 in France and USD 450-850 in the Netherlands. Value is affected by the culture technique and concomitant labour costs, which range from USD 400 to 1,600/tone for dredged and rope cultured products respectively. Prices for farmed mussels are also affected by irregular landings from the wild fishery. International mussel trade has risen consistently over the last 20 years in terms of total volume as well as in exports as a percentage of domestic supply (e.g. Europe, 14 percent to 35 percent in 1985 and 2000 respectively). The import-export market for fresh M. edulis is driven either by seasonal meat quality and/or low supply. France imports half of its annual consumption, mainly M. edulis, from northern countries (September to April) and M. galloprovincialis from southern countries (May to August). This results from an increasing demand for fresh products and also from the seasonally reduced meat quality of M. edulis following spawning. This stimulates import/export trade since simply increasing production does not address this issue.

Exports mainly comprise processed products, which provide added value, and may be a major driving factor for M. edulis culture development. In the Netherlands, part of the extensive dredged mussel culture is processed for cooking, canning, and freezing, as well as to produce a variety of commodities. It is the view of the Irish industry that rope mussels do not travel live as well as bottom cultured mussels. Therefore, 80 percent of Irish rope production was processed in 2001; then in 2002, processors imported fresh mussels from Spain, Greece and other countries because they had exhausted Irish supplies. In 2001, the volume of the Irish processed mussel product range comprised 74 percent vacpack frozen, 13.5 percent vacpack chilled, 7.5 percent IQF in shell and 5 percent others (meats).

Import prices tend to be lower compared to export prices, reflecting the role of processing in this market, and facilitating international trades when local production cannot sustain the demand.

Status and trends

In Europe, most of the mature, large scale producing nations, such as France and the Netherlands, have become broadly stabilized in terms of production; the main source for incremental output with the present technology will be from peripheral nations (UK, Norway, and Ireland). Canada and Ireland markedly increased their farmed output between 1993 and 2002. Forecasts for the mussel industry are that there is likely to be a greater emphasis on processed products (prepared dishes) rather than on the live on-shell market, and that higher competition for raw material might be the near future limiting factor.

Main issues

Besides bird predation and water quality deterioration caused by pollution, which are likely to impose further constraints on the expansion of existing mussel farming operations, two main problems for the mussel industry can be linked closely to its future development: seed shortages and biotoxins that lead to long-term industry closures.

Seed shortages

Seed shortages have affected the mussel industry in several European countries over the last ten years. Three case studies can explain the present situation:

In Ireland, the dredged sector has witnessed a drastic production increase with no real plan for sourcing seed to support this development; this has led to seed shortages and the risk of over-exploitation of natural beds. The 2003 seed requirement was estimated to be 180,000 tones, but the supply was around 30,000 tones. Seed supply can be improved by a better understanding of spat settlement and improved survey and management practices.

In the Netherlands, irregular yearly recruitment led to repeated seed imports from Germany, Belgium, France and the UK. The quantity of spat removed by the farmers from natural beds has been determined by a survey. A large part of those beds have been recently closed, to create a food reserve for eider ducks and oyster catchers; this has led to a decreasing spat quota per farmer.

Global climate change may also affect spat recruitment and seed supply: the summer of 2003 was characterized by an abnormal heat wave in French waters, leading to massive mussel spat die-offs in >26 °C seawater temperatures. A significant mussel population change would occur if it were to become a more regular occurrence.
Biotoxins

The extent and scale of impact of the various biotoxins in Europe and North America is well documented by the on-going monitoring networks and quality controls developed to protect the public from diarrhetic shellfish poison (DSP) and paralytic shellfish poisoning (PSP).

PSP and DSP toxins have been recorded throughout the European continent, as well as in the Gulf of Maine.

However, ASP (domoic acid) has been less frequently reported, but has been noted in eastern Canada and North America, causing illness and deaths, and in Spain, Ireland and Scotland. Its impact makes it one of the most economically destructive biotoxins, with associated long-term industry closures, and sales prohibitions. In addition, AZP (azaspiracid poisoning) resulting from a dinoflagellate species (Protoperidinium sp.) has been reported in Ireland as causing human health problems.

While the cultivation of blue mussels has shown great potential in several countries, the inability to control algal toxins is a major limiting factor. Depuration is a likely potential option for the shellfish industry, to manage the impact of shellfish toxins.



FAO. © 2004-2011. Cultured Aquatic Species Information Programme. Mytilus edulis. Cultured Aquatic Species Information Programme. Text by Goulletquer, P. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 1 January 2004. [Cited 12 September 2011]. http://www.fao.org/fishery/culturedspecies/Mytilus_edulis/en

FAO. © 2005-2011. Cultured Aquatic Species Information Programme. Mytilus galloprovincialis. Cultured Aquatic Species Information Programme . Text by Figueras, A. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 1 January 2004. [Cited 12 September 2011]. http://www.fao.org/fishery/culturedspecies/Mytilus_galloprovincialis/en

http://ec.europa.eu/fisheries/marine_species/farmed_fish_and_shellfish/mussels/index_en.htm