CHANGES IN CHEMICAL-COMPOSITION AND BIOMASS DURING THE TRANSITION FROM ENDOGENOUS TO EXOGENOUS FEEDING OF SPARUS-AURATA L (PISCES, SPARIDAE) LARVAE REARED IN THE LABORATORY

Larvae of the gilthead seabream, Sparus aurata L., were reared during the first weeks after hatching at 16, 19.5 and 24-degrees-C. Changes i n biomass were studied in terms of dry weight and of carbon, nitrogen and hydrogen content. Body composition varied primarily during the per iod of absorption of yolk and shortly after the onset of exogenous fee ding. During the yolksac stage, dry weight and carbon and hydrogen con tent decreased markedly from their values at hatching, while nitrogen content showed only a very slight decrease. After the absorption of yo lk, whether in the presence or absence of food, the percentages of car bon, hydrogen and nitrogen tended to remain constant. No important dif ferences were found in the body composition of growing larvae in relat ion to temperature. However, the rates of variation of the body consti tuents were more influenced by temperature in the yolksac stage than d uring the exogenous feeding phase.