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.