Comparison of the traditional outdoor and recirculation indoor rearing systems on survival rate and growth performance of common carp (Cyprinus carpio) larvae during early development

The larvae of common carp (Cyprinus carpio L.) were studied for 6 weeks in an indoor recirculatory system (RAS) and an outdoor earthen pond to compare their effects on growth performance and survival rate. Larvae reared in outdoor earthen ponds achieved significantly higher total length, weight, weight gain, and length increments than indoor groups (P≤0.05). However, the indoor recirculatory system had the highest survival rate (83±1.9%) than outdoor earthen ponds (42±3.6%) (P≤0.05). The results of the present study revealed that the raising system has a significant impact on the survival and growth performance of the larvae in common carp, and the best growth performance was in the outdoor earthen ponds, while the better survival rate was recorded in the indoor recirculatory system. Therefore, to minimize mortality and maximize survival rate, it is suggested that the larvae were released after hatching into closed and controlled rearing systems before being reared into earthen ponds after starting the exogenous feeding.