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

¹ Centre d'océanologie de Marseille, université de la Méditerranée, CNRS UMR 6535 LOB, station marine d'Endoume, rue de la Batterie des Lions, 13007 Marseille, France
² Centre d'océanologie de Marseille, université de la Méditerranée, CNRS UMR 6540 Dimar, station marine d'Endoume, rue de la Batterie des Lions, 13007 Marseille, France
³ CREMA L'Houmeau, CNRS Ifremer, B.P. 5, 17137 L'Houmeau, France

Received: 16 December 1999
Accepted: 10 June 1999

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 L·h⁻¹ 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.