Combined effects of temperature and salinity on the larval development of the estuarine mud prawn Upogebia africana (Crustacea, Thalassinidea)

The larval stages of the mud prawn Upogebia africana were reared in the laboratory, from hatchings of females collected in the Mgazana estuary, South Africa. The larvae were tested for the combined effects of temperature and salinity in a factorial designed experiment, using 3 females and 2 replicates of 10 larvae per combination. Combinations were made from 5 temperatures (15, 20, 25, 30 and 35 °C) and 4 salinities (15, 25, 35 and 45). Results were tested by ANOVA and multiple regression was applyed to generate contour models by polynomial equation. Results showed that U. africana develops optimally in near to sea water salinity at around 25 °C, with slightly wider tolerance to low salinity in zoeal stage I, and with increased moult rate at lower salinity in late stages. A comparison with similar experimental results for other species is made, namely in view of the life cycle strategies for dispersal and return migration.