ENERGY BUDGET OF A MYTILUS-EDULIS-L POPULATION DURING ITS 1ST YEAR ON BOUCHOTS IN THE BAY OF MARENNES-OLERON

The energy budget of a population of Mytilus edulis cultured on bouchots in the bay of Marennes-Oléron was worked out from measurements of shell (7050 kJ m-2 year-1) and flesh (40 636 kJ m-2 year-1) production, and from field biodeposition (348 775 kJ m-2 year-1). The losses of energy induced by oxygen consumption (58 367 kJ m-2 year-1) and by NH4 excretion (6202 kJ m-2 year-1) were measured in the laboratory under near field conditions. Production was negative in winter. During the phytoplanktonic bloom in June, production reached a maximum. The mean assimilation efficiency (23%) was near values recorded in the bay for other bivalve molluscs; nevertheless, the net production efficiency (47.8%) was representative of values described for this species. There was an inverse relationship between the amount of organic matter in sea water and the assimilation efficiency, and a positive relationship between food quality and the production of the mussel population. © 1990.