Rates of water processing, oxygen consumption and efficiency of particle retention in veligers and young post-metamorphicMytilus edulis

Abstract

Abstract Rates of water processing and particle retention were determined in veligers and post-metamorphic juvenile M. edulis, reared in the laboratory, by measuring the rate at which particles of different sizes were cleared from suspensions. Veligers cleared 2.5 -3.5 μm particles at the highest rate, and particles smaller than 1 μm or larger than 8-9μm could not be consumed. The veligers cleared the water at a constant rate for 8 hours (11.4 μl · h-1 · larva-1) at concentrations of 1.5-5.5 × 103 Isochrysis galbana cells · ml-1. At abnormally high algal concentrations the clearance fell significantly, probably because the capacity of the stomach was exceeded, while the grazing rate became independent of the algal concentration (80 cells · h-1 · larva-1). The retention efficiency for young postmetamorphic mussels (1-4 mm shell length) was 100 % for particles down to 4 μm, decreasing to 20 % for 1, μm particles. The filtration rate (F, ml · h-1) in the juveniles (total organic dry weight, W, 70-10000 μg) c...