Fuel and metabolic scaling during the early life stages of Atlantic cod Gadus morhua

摘要: The simultaneous effect of temperature (5, 7, 10 and 13°C) light on the rates oxy- gen consumption ammonia excretion larval early juvenile Atlantic cod Gadus morhua was examined. Larvae increased their mean dry body mass by 2000 times within 48 d. Instantaneous growth rate exceeded 30% d -1 towards end study period, proportionality fol- lowed a triphasic pattern, during which water content significantly declined but no inflection could be detected in metabolic exponents. Data were rigorously tested via Model-I (least squares) Model-II (geometric mean) regression techniques, aerobic found to scale allometrically with both wet mass. exponent not affected increasing temperature, decreased presence (b = 0.88 0.89 for light-adapted larvae; b 0.90 0.91 dark-adapted larvae). small larvae (4 7 mm standard length, SL) caused 30 40% increase rate, while observed larger juveniles (40 60 SL). Acute acclimation 4 SL (0.04 350 mg mass) demonstrated normal thermal sensitivity Q10 values 2.4 2.6 larvae. Rates also scaled allo- metrically showed greater variability compared Comparison molar oxygen revealed that have high reliance amino acids as fuel energy dissipation. With lipids assumed co-substrate, estimated account 70 95% total substrate oxidation up (first 3 wk post-hatch development). Beyond SL, began decline, even 40 still represented dominant source fuel. For between 20 remained unaffected food gut. short-term fasted (35 SL), however, substantial decline observed. This indicates fasting (8 12 h) conserve acids, rather than funneling them into tricarboxylic acid cycle.