Species group: Clams, Scallops and other Bivalves
Other common names: Chilean Mussel
Scientific name: Mytilus edulis
Blue mussels are typically found on exposed intertidal shores where they attach themselves to rocks by means of strong byssal threads (the 'beards'). The two hinged shell halves of the mussel are the 'valves' and these are held together by a ligament on the convex side. The shell is then closed by a strong internal muscle. The shells protect the soft bodies of the mussels within from predation and from desiccation when they are exposed by the tide. Blue mussels are commonly harvested for food across the globe. They are particularly amenable for aquaculture and are extensively farmed in China, Australia, New Zealand, Western Europe and Canada. Under optimal conditions, blue mussels grow to harvestable size in two years. Mussels have two distinct sexes, though external appearance is the same. Mussels have two distinct life stages, a free-swimming larval form and an essentially static shelled form. Blue Mussels are classed as semi-sessile, as they have the ability to detach themselves from the surface to which they are anchored, only to re-attach themselves. This allows them to move up and down the water column as needed. They are not really suitable as pets, this is an animal for the aquaculturalist only. Economically, though, they are an important human food resource and are very low maintenance to grow and farm, especially with modern seeding and harvesting techniques.
The Blue mussel is a medium-sized bivalve mollusc from saltwater habitats whose shell is elongated and asymmetrical with the hinge located at the base of the shortest side.The shell is essentially triangular in size, with a convex long edge on one side (where the valves hinge) and a concave long edge on the other. The animal grows outwards from the base and the growth is visible as a series of finely-sculpted concentric rings on the shells. The outer colour of the shell tends to be either purple or blue though brown and green-tinged specimens are seen. The inner surface is white or cream, being a prismatic calcitic layer.
Mussels are essentially sedentary filter-feeders, so activity levels are low. At the microscopic level they present some fascinating behaviors and they are surprisingly social animals but you will not notice this.
Mussels need tidal waters and though they can be farmed, they are not suitable as pets as they require either strong water currents or need to be exposed by tidal flows twice a day. It is these tidal flows that bring them the microplankton and food particles they live on. There are three main methods of farming mussels and for each, suitable small mussels need to be harvested (often by surface dredging) to seed the growing beds:
1. Intertidal Growth Method: Stout pilings are driven into the sea or intertidal zones of estuaries. Stout ropes are then attached to the pilings in a spiral pattern. Mussels are then tied to the ropes and are secured with netting to prevent them from falling or drifting off. This is the typical method employed in France and Spain.
2. Long line method. This is a methodology pioneered in New Zealand and now employed in Australia. Mussels are attached to ropes which are then twisted together to form chains. The rope backbone, which can be up to 200m long, is then supported on large plastic floats in deep tidal areas. This method needs heavy equipment, but harvesting and re-seeding can be automated.
3. Tidal mesh sleeves. Here, mussels are collected and placed in mesh sleeves which are then suspended in bays, inlets or other tidal waterways. This method is the most sustainable and environmentally friendly as the mussels are collected from the same area where they are farmed. This method relies on nutrient rich waters, but does not require feeding of the mussels. This is the main method employed in Canada and Britain.
small seed mussels, Britain.The Menai Straits