Effects of temperature on the instantaneous oxygen consumption rate of obscure puffer (Takifugu obscurus) and tawny puffer (Takifugu flavidus) juveniles

Abstract:

The instantaneous oxygen consumption rates of obscure puffer (Takifugu obscurus) and tawny puffer (Takifugu flavidus) juveniles (about 20 g mean weight) were measured by closedchamber respiration methods at seven temperatures (11, 15, 19, 23, 27, and 31 ℃). The results showed that the instantaneous oxygen consumption rates (V) of obscure puffer and tawny puffer juveniles decreased as the experimental time (t) increased, showing the power law model (V=at^b, r²>0.98, p<0.01). Within suitable dissolved oxygen range, the oxygen consumptions of obscure puffer and tawny puffer juveniles were both directly related to the concentration which could be denoted as “conformers”, i.e. V decreased with decreased dissolved oxygen level, whereas, below that range, the juveniles maintain a constant oxygen consumption rate to ensure the basic life activities, regardless of the concentration of dissolved oxygen, and there are the socalled “regulators”. The oxygen consumption rate and dissolved oxygen had a significant quadratic relationship (r²>0.95, p<0.01). The oxygen consumption rate increased rapidly as the temperature increased (11-31 ℃), showing a linear relationship in the range of temperatures investigated (r²>0.95, p<0.01). Within the temperature range of the conventional pond culture, the oxygen consumptions of obscure puffer juvenile were higher than that of tawny puffer. The Q₁₀ of obscure puffer and tawny puffer juveniles were 2.84 and 2.65, respectively. In actual culture and transport processes of obscure puffer and tawny puffer, when dissolved oxygen level is below 3 mg/L, the emergency aid measures should be started.