Effects of Water Temperature on Embryonic Development, Hatching Success and Survival of Larvae of Siamese Mud Carp Henicorhynchus siamensis (Sauvage 1881)

Abstract

Temperature is an important environmental factor for aquatic animals especially fishes, in particular during the early life stages. The objectives of this study are to investigate (a) the effect of different water temperature (26, 28, 30, 32 and 34 °C) on embryo development and newly hatched larvae of Siamese mud carp Henicorhynchus siamensis (Sauvage 1881) and (b) the effect of acute temperature change to the newly hatched H. siamensis larvae. The development was divided into two phases viz., firstly, from zygote to gastrula periods and, secondly, segmentation to hatching periods. The H. siamensis larvae did not successfully hatch at the incubation temperatures of 26 and 34 °C. The development times of the three remaining temperatures were relatively closed at the first phase, in contrast to the second phase, which were quite varied. The hatching times at 28, 30 and 32 °C were about 652, 485 and 457 min, respectively. The percentages of hatching success of the three respective temperatures were 73.76±2.37%, 73.90±1.44% and 61.42±11.19%, respectively. For the effect of acute temperature changes, numbers of dead larvae were not significantly different between 30 and 28 °C (P-value = 0.30), but there was a significant difference between 30 and 32 °C (P-value < 0.01).