Clearance rate responses of Mediterranean mussels, Mytilus galloprovincialis, to variations in the flow, water temperature, food quality and quantity

Abstract

The impact of Mediterranean mussels ( Mytilus galloprovincialis Lamarck) on particle removal from the water column under different flow velocities was measured in the laboratory within a recirculating flume. At 20 °C, the filtration rates increased with current velocity up to 20–25 cm .s -1 . Filtration rates remained the same at 26 °C. At high phytoplankton concentration (Cryptophyceae: 8 500–11 000 Cryptomonas sp. cells .mL -1 ), filtration rates were low (0.2–0.4 L .h -1 per standard individual of 1 g dry weight), whereas higher filtration rates (0.5–2.5 per standard individual) were observed with lower concentrations of the algae Prorocentrum minimum (Dinophyceae : 1 300– 5 800 cells .mL -1 ). The filtration rates of M. galloprovincialis were affected by high phytoplankton loads, and exhibited a maximum related to current velocity. Our results suggest that mussels, feeding over a wide range of seston concentrations and flow velocities, show an adaptive behaviour in an area where environmental conditions are known to vary drastically.