Growth measurements, feeding rates, metabolic responses from respirometry, carbon-nitrogen ratios and mortality of European sea bass (<em>Dicentrarchus labrax</em>) larvae under conditions of elevated <em>p</em>CO2 and temperature.

Ocean acidification, caused by rising concentrations of carbon dioxide (CO2), is widely considered to be a major global threat to marine ecosystems. To investigate the potential effects of ocean acidification on the early life stages of a commercially important fish species, European sea bass (<em>Dicentrarchus labrax</em>), 12,000 larvae were incubated from hatch under a matrix of two temperatures (17 and 19 °C) and two seawater <em>p</em>CO2s (400 and 750 µatm) and sampled regularly for 42 days. In addition, as the period when cultured fish are weaned onto dry food is typified by higher mortality, 6 glass aquaria were connected to the 2 systems set to 19 °C (400 and 750 µatm pCO2, 3 aquaria each) to investigate the effect of this additional stressor. Fifty larvae (d₄₉ post-hatch) were transferred from each 19 °C tank into a corresponding glass aquarium and then gradually weaned onto dry food over 7 d and maintained for a total of 26 d (larvae were d₇₅ post-hatch at the end of the weaning trial) with mortality recorded daily. The routine metabolic rate (RMR) and maximal metabolic rate (MMR) of post-metamorphic (juvenile) animals (d_67-69) from the main study was also determined using aquatic respirometry.