Relationship between Quantities of Faecal Material Produced and of the Suspended Matter Removed by the Japanese Oyster

Abstract

Quantities of faecal material produced by the Japanese oyster varied seasonally, reaching maxima in October. This seasonal rate was caused by activities of the gills of oysters. Daily quantities (V) of suspended matter removed by the gills of a single oyster could be calculated by means of the equation V(mg/day) = suspended matter (mg/l) × filtration rate (l/h) × 24. As a part of this calculated quantity was digested and absorbed, quantities of faecal material produced were a little smaller than that of suspended matter calculated using the above equation. Oysters retained approximately 40 to 50 per cent of the suspended matter contained in the inhalent current and this rate did not vary throughout the year, therefore, daily quantities of suspended matter removed could also be estimated from the rates of water transport. Rates of filtration and water transport per gram wet weight of meat were a linear function of the water temperature (t°C) and could be expressed by equations Filtration rate (l/h/g of meat) = −0.308 + 0.066t Rate of water transport (l/h/g of meat) = −0.002 + 0.109t. © 1978, The Japanese Society of Fisheries Science. All rights reserved.