Individual variation in the rate of oxygen consumption by zebrafish embryos

A sensitive microsensor-based method was used to measure oxygen consumption of individual zebrafish Danio rerio embryos at 6 h intervals from 24 to 75 h post-fertilization. An increase in oxygen consumption rates from 4.54 to 8.29 nmol O(2)h(-1) was found during this period. At the individual level the differences in oxygen Consumption rates caused the total oxygen consumption from 24 to 75 h post-fertilization to vary between 0.261 and 0.462 mumol O-2 per individual with a mean of 0.379 pmol O-2 per individual. A separate carbon mass balance study corroborated the mean total oxygen consumption obtained by yielding a respiratory quotient of 0.80 for this period. These results suggest that there is significant intraspecific variation in the metabolic rate of developing zebrafish embryos, which may influence other early life-history traits such as growth and starvation resistance. (C) 2004 The Fisheries Society of the British Isles.