The effects of temperature, body weight and hypoxia on the oxygen consumption of the Mexican mojarra, Cichlasoma urophthalmus (Günther)

Abstract. The oxygen consumption rate of the Mexican cichlid, Cichlasoma urophthalmus Günther, was determined using closed-circuit respirometry at 20,25,30 and 36°C over a weight range of l·91–116g. Oxygen consumption rates ranged from 31 to 4500mg/kg/h and were slightly higher than for other cichlid species reported. Q10 was 2·49 between 20°Cand 30°C, but showed a direct increase with temperature. The species is an oxygen conformer, with an estimated critical oxygen tension of 70 mmHg at 28°C. This confers good low oxygen tolerance and some advantages for culture. The fish were able to withstand virtual anoxia for up to 2h. The significance of these results is discussed.