Physiological energetics of mussel larvae

Food uptake of marine mussel larvae (Mytilus edulisL.) was estimated in relation to larval size, temperature (6, 12, 18°C) and food concentration (1, 2, 5 , 10, 20 and 40 Isochrysis galbana cells 1r1-I). Filtration rates were maximal at low food concentrations (between 1 and 5 cells 1r1-l). This was called 'filtration capacity' and expressed as a function of larval size. Ingestion rates reached a plateau with increasing food concentration above 10 cells p1-l. Maximum rates were called 'ingestion capacity' and expressed as weight and volume of particles passed through the gut. When previously starved larvae enter a food suspension of more than 10 cells p1 l , ingestion rate overshoots the ingestion capacity level for up to 1.5 h at 12°C. This is caused by filling of the gut, because it was not paralleled by a n overshoot of the filtration rate above the filtration capacity level Particles between 1 and 9 ktm diameter were taken up, with maximum retention efficiency at about 3.5 pm particle diameter.