Reared sea bass (Dicentrarchus labrax) represent 13% of the economic weight of the Mediterranean aquaculture production (FAO, 2005) and is a subject of selection program. However, the traditional goal of selection that prevailed in the last century, i.e. increasing productivity, have to be modulated by new objectives such as better feed management or increasing fish welfare. The aim of our study is to evaluate the influence of domestication and selection, and their interactions with stress, on the energy balance in sea bass (Dicentrarchus labrax). Therefore, we used two experimental datasets and analysed their results through a mathematical model. Four strains of sea bass were studied: i) Wild strain, ii) Domesticated strain (first generation obtained by reproduction in rearing condition without selection), iii) Selected strain 1 (same first generation obtained but by siring the 5% longest fish) and iv) Selected strain 2 (first generation obtained by Prosper selection (Chevassus et al., 2004)). In the first experiment (Vandeputte et al., 2009), growth was monitored while the four strains were raised separately with ad libitum feeding. In the second one, the fish were exposed to recurrent stress events, while their food consumption and their weight were monitored throughout the experiment (the food was delivered by self-feeder). Since the goal of the present study is to quantify the fish energy balance, we used a bio-energetic model to quantify energy fluxes and to compare between strains and stress conditions.