This study was designed to measure responses of four-year-old black-lip pearl oysters(Pinctada margaritifera) to different temperatures and foodconcentrations and to identify the energy requirements of each sex. Oysters were fed amonospecific microalgal diet of Isochrysis affinis galbana(T-iso). Measurements of oxygen consumption and ingestion rates were carried outat 24 °C and 27 °C and at two algal (T-iso) concentrations: 5000 and 30 000 cellml-1. Glycogen content in adductor muscle, absorption efficiency and scopefor growth were also estimated. Females and males responded differently to environmentalfactors, with food level being the most influential parameter. Oxygen consumption andabsorption efficiency were significantly higher in females than in males, but males hadsignificantly higher glycogen content than females. At high food concentration, glycogencontent, ingestion rate, oxygen consumption, and scope for growth were significantlyhigher than at the low food concentration. Only absorption efficiency was significantlyhigher at the low food concentration. Oxygen consumption was significantly higher at 27 °Cthan at 24 °C. These results indicate that females and males have different bioenergeticfunctioning and that energy demands for reproduction are higher in females.