Effect of temperature on the behaviour of the endeavour prawns Metapenaeus endeavouri (Schmitt) and Metapenaeus ensis (De Haan) (Decapoda : Penaeidae)

Abstract

The effect of water temperature on the duration of emergence and speed of movement of adult endeavour prawns, Metapenaeus endeavouri and M. ensis, was investigated in the laboratory under controlled conditions from 20˚ to 32˚C. The behaviour of 50 prawns was recorded on videotape over 48 h at five temperatures (20˚, 23˚, 26˚, 29˚ and 32˚C). In general, both species emerged from the substratum during dusk and remained on the substratum until dawn or just before dawn when they buried again. At 32˚C, however, some M. endeavouri emerged for much less time and started to bury shortly after midnight. The mean daily duration of emergence for M. endeavouri varied with temperature and was higher at 26˚ and 29˚C (653 40 min per day) than at other temperatures. In contrast, the mean duration of emergence for M. ensis was not significantly affected by temperature (range of times 663 45 to 693 9 min). The pattern of the mean hourly speed of movement for M. endeavouri varied with temperature, whereas that for M. ensis was bimodal at most temperatures: they were more active during dusk (1700 to 1800 hours) and dawn (0400 to 0500 hours) than at other times.