Mytilus galloprovincialis has a smooth, dark-blue to brown shell that is slightly broader and flatter than its northern relative, the blue mussel. Adults commonly reach 60–80 mm in the Mediterranean and can exceed 100 mm in optimal conditions. Like all Mytilus species, it attaches via byssal threads — a bundle of 50–100 tough protein fibres that bond strongly to virtually any solid surface. The species dominates in waters above 14 °C and tolerates salinities as low as 15 ppt, which accounts for its prevalence in the Mediterranean, along the Atlantic coasts of Iberia and France, and throughout the Black Sea.
Mediterranean mussel fouling is the single largest maintenance cost for sea-bass and sea-bream cage farms in Greece, Turkey, and the western Mediterranean. Biomass accumulation rates of 15–25 kg per square metre per year are typical on unprotected nets, and structures submerged near established wild populations can reach that level within six months. The added weight — sometimes exceeding the net’s own mass several times over — deforms cage geometry, stresses moorings, and demands frequent, expensive cleaning operations. Estimate the impact on your operation with the cost calculator.
Control relies on a combination of mechanical scraping, high-pressure washing at 100–150 bar, and periodic net replacement. Copper-alloy mesh prevents mussel attachment entirely and lasts 5–7 years, but the initial cost is 3–5 times that of nylon. Compare these methods to find what suits your site. Because M. galloprovincialis spawns almost year-round in the eastern Mediterranean, there is no true fouling-free window — consult the fouling season calendar for regional timing and plan cleaning schedules accordingly.
Control Methods
Manual scraping Copper-alloy mesh Air-drying High-pressure washing