Mussels are found in a wide variety of habitats, from tidal areas to fully submerged zones, with a broad range of temperature and salinity. They feed on phytoplankton and organic matter by constantly filtering the sea water and are therefore always farmed in areas that are rich in plankton. Water quality is a very important factor for mussel rearing. They are picked from the nature when they are young, placed to the culturing system and fattened. Mussels are the most versatile shellfish species as regards presentation and packaging. They may be sold loose, in pre-packed mesh bags or in chilled, ready-to-use vacuum packs