Temperature effect on development and reproduction of the androdioecious clam shrimp, eulimnadia braueriana (branchiopoda: Spinicaudata)

Abstract

We examined the effects of temperature on the androdioecious clam shrimp Eulimnadia braueriana Ishikawa, 1895 from Taiwan. We conducted aquacultural experiments at four temperatures (15, 20, 25, 30°C). We found that hatching rate was significantly higher at 20°C (85%) and 25°C (60%). The earliest hatching time (EHT) ranged from day 1.6-5.8, and the hatching period was significantly longer for cultures at 15°C. The earliest maturation time (EMT) of hermaphrodites ranged from day 5.3-18.3, and was significantly shorter for cultures at higher temperatures; EMT of males ranged from day 13.3-18.3, but did not vary significantly at different temperatures. Growth rate increased with increasing temperature, but survival rate decreased. Although males were rare, only 0.14-1.44% per trial, the chances of sexual reproduction should increase at lower temperatures, as there was a significant difference in EMT between genders at higher temperatures. Clutch size was generally correlated with body length. Clutch size varied with temperature, and was larger at medium temperatures (20 and 25°C) at EMT, and was greatest at 30°C post-EMT.