The effect of four temperatures, ranging between 17 degrees C and 32 degrees C, was studied on development and lipid reserve management of Crassostrea gigas larvae. No effect of temperature was found on larval mortality, as high survival (>90%) was recorded before competence at all temperatures studied. Temperature did, nonetheless, have a strong effect on growth and settlement success. At low temperature (17 degrees C), larvae competent to metamorphose were only observed from day 23 and only a low percentage finally achieved metamorphosis (12%). The opposite was seen at temperatures >= 27 degrees C: larval competence appeared at day 18 and led to high rates of metamorphosis (60-90%). This difference at settlement seemed to be linked to larval growth, which showed rates of 7 mu m d(-1) at 17 degrees C vs. 10.5 mu m d(-1) at 32 degrees C. In addition, a higher accumulation of lipid reserves at low temperature was revealed by both biochemical (TAG/ST) and colorimetric (OLI) methods. In fact, the lower the temperature, the higher the mean TAG/ST levels recorded (6-9 at 17 degrees C vs. 2-4 at 32 degrees C). In the same way, larvae reared at 17 degrees C had a percentage lipid surface coverage between 19 and 29% (at sizes between 80 and 230 mu m), while lipids covered only 5 to 16% of the surface of larvae reared at 32 degrees C (at size <250 mu m). Neither of these physiological indices can, however, provide a relevant indication of the larval performance induced by different rearing temperatures. (C) 2010 Elsevier B.V. All rights reserved.