EFFECT OF TEMPERATURE AND SALINITY ON THE OXYGEN-CONSUMPTION OF LABORATORY PRODUCED PENAEUS-VANNAMEI POSTLARVAE

The routine rate of oxygen consumption by Penaeus vannamei postlarvae (mean weight = 0.15 g) was determined at four temperatures and five sa linities. The time course of oxygen depletion in the chambers was inde pendent of the dissolved oxygen (DO) level down to 1.3 mg/l. Oxygen co nsumption during normoxic conditions increased with temperature and ra nged from 0.0060 mg/g/min at 25 ppt and 20 degrees C, to 0.0183 mg/g/m in at 35 ppt and 32 degrees C. Salinity had only a marginal effect on consumption. At high salinities, there was an increase in the metaboli c demand, probably caused by an apparent loss in the capacity to maint ain the osmotic and ionic balances as temperature increased. A critica l point (Pc), where oxygen consumption by the shrimp changes from bein g independent of DO level to being dependent, was found. Pc was correl ated to temperature. Below Pc, oxygen consumption was reduced to appro ximately 34% of the normal rate.