Effects of temperature and salinity on the larval development of the Chinese mitten crab Eriocheir sinensis (Decapoda: Grapsidae)

Larvae of the Chinese mitten crab Eriocheir sinensis H. Milne-Edwards were reared in the laboratory under 25 different combinations of constant temperature (6 to 18 ' C ) and salinity (10 to 32 %O S). Different schedules of changing salinity were tested only in the final larval stage, the megalopa. Pelagic larval development comprises a total of 5 zoeal stages and 1 megalopa. An additional (stage W ) zoea and in one case an additional megalopa (transitional to the juvenile) were occasionally observed under unfavourable conditions with low salinity (5 15 %OS). Successful development from hatching to metamorphosis occurred only at temperatures 2 12 "C. With increasing temperature, both overall survival and range of salinity tolerance increased, whereas development duration decreased exponentially. Regression equations describing this relationship are given for different larval stages and salinities. Development time increased at unfavourably low or high salinities (i.e. where mortality also increased). Zoea I was very euryhaline, with a n optimum in slightly brackish water ( 2 5 0 ~s ) .