Detalle de: Effect of temperature on the metabolism, behaviour and oxygen requirements of Sparus aurata

We investigated the effect of temperature on the limiting oxygen saturation (LOS) of\ngilthead sea bream Sparus aurata. This threshold was defined as the % O2 saturation where fish\nno longer upheld their routine metabolic rate (RMR, the metabolic rate of fed and active fish) during\na progressive decline in oxygen saturation. S. aurata (398 ± 10 g, mean ± SE) were kept in 3\nreplicate tanks and subjected to 3 changes in temperature: 16 to 20°C, 20 to 16°C and 16 to 12°C.\nAt each temperature, fish were left to acclimatize for 8 to 10 d, before daily feed intake (DFI), the\nroutine oxygen consumption rate (routine MO2, mg kg−1 min−1) and the LOS were measured. In\naddition, at 20°C the swimming speed was measured in fish subjected to a decline in O2 from full\nair saturation to levels below the LOS (minimum of 8−10% O2). For the temperature range tested\n(12−20°C), DFI, MO2 and LOS increased exponentially with temperature (7.5-, 3.6- and 2.2-fold,\nrespectively) with mean (± SE) LOS being 17 ± 1, 21 ± 0 and 35 ± 5% O2 at 12, 16 and 20°C, respectively.\nA gradual decline in swimming activity was observed as O2 declined below the LOS, indicating\nincreasing metabolic stress and/or a ‘sit-out’ coping strategy which may prolong survival\ntime in severe hypoxia. The results show the importance of temperature as an influential variable\nover the environmental O2 requirements of S. aurata.