Certifier : 
Lloyds Register (Acoura)
Certified status : 
Certified since : 
20 Apr 2012
Certificate expires : 
19 Oct 2022


The blue mussel is a widely distributed bivalve shellfish that adapts to a wide variety of ecological situations. Mussels are filter feeders, feeding on phytoplankton and suspended organic matter in the water column. This reliance on a natural food source, coupled with their general sessile (fixed) nature and large reproductive capacity, makes them ideal for cultivation.

Seed mussels or “spats” are initially collected from the wild, where larvae collect on spat collectors suspended in the water. These are subsequently grown on in cultivation plots on ropes attached to the seabed. However, once a farm is established it could become a net exporter of larvae: each cultivated mussel has the potential to produce around 3 million gametes per year, so the reproductive output of the mussel stock in cultivation is enormous.

The 12 cultivation areas under certification in Limfjorden, Denmark are licensed to five operators, and cover a total area of 214 hectares. Most of the licensed areas can be used for cultivation of both blue mussels and oysters, though no oyster cultivation is taking place at present. 

The status of the cultivated stock is monitored by each mussel farmer within their farm area.  Effective mussel farm management requires careful recording of stocking densities and harvest output from the farm to ensure that it is managed optimally.  The farms produce around 2,500 tonnes of cultivated mussels per year.  

Blue mussel (Mytilus edulisimage © Scandinavian Fishing Year Book