A corrected formula for calculation of filtration rate of bivalve molluscs in an experimental flowing system

Abstract

The filtration rate of Mytilus edulis was measured in a flowing system by estimating the particulate matter concentrations at the inflow (C1) and outflow (C2) of the experimental chamber and immediately surrounding the bivalve (C0). Filtration rate was calculated as R1 = F(C1 – C2)/C0…(1), where F = flow rate through chamber. This formula differs from that previously used in flowing systems (R"t = F(C1 – C1/C2)…(2), by accounting for dilution of inflowing water as it enters the experimental chamber. Formula (1) was used to show that flow rate through the experimental chamber has a negligible effect on filtration rate whereas the use of formula (2) indicates erroneously that flow rate and filtration rate are positively correlated. The particulate matter concentration around the bivalve is also shown to have a negligible effect on filtration rate within the limits tested of approximately 2000–20000 particles ml-1.