Temperature preferendum of postlarval black tiger shrimp (Penaeus monodon)

The environmental temperatures preferred or selected by postlarval black tiger shrimp Penaeus monodon (body weight 84 ± 25 mg and body length 2.66 ± 0.21 cm, mean ± s.d.) acclimatized to 16, 20, 24, 28, 32 or 36°C, were determined in a horizontal gradient (17–37˚C). The results indicated that the crustaceans were competent in detecting thermal discontinuities and in showing preference. The mean temperature selected by the postlarvae rose from 20.0˚C to 25.6˚C and the mode from 15˚C to 27˚C when the acclimation temperature was increased from 16˚C to 36˚C. The preferred temperature of the shrimp was not significantly different among the groups acclimatized at 24˚C, 28˚C and 32˚C. The final preferendum of the shrimp was estimated to be 23.2˚C, which is considerably lower than the optimal growth temperature for the species.