An in-pond tank culture system for high-intensive fish production: Effect of stocking density on growth of grass carp (Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream(Megalobrama amblycephala Yih, 1955)

Abstract

Pond partitioned aquaculture system is developed in recent years, and it contributes to increasing yield and lowering land occupation. Based on the concept of partitioned aquaculture system, a new in-pond tank culture system (IPTCS) was constructed in this study. This system consists of culture tank, capture and aeration module, waste collection module, and vertical flow constructed wetland (VFCW), and the effective rearing area takes up about 10.05% of the pond area. In IPTCS, grass carp ( Ctenopharyngodon idella Valenciennes, 1844) and blunt snout bream ( Megalobrama amblycephala Yih, 1955) were reared at high and low stocking densities for 120 days. The initial density of grass carp in the high and low density groups was 15 kg m −3 and 7.5 kg m −3 , respectively, and that of blunt snout bream were 10 kg m −3 and 5 kg m −3 . During the experiment, the aeration module worked 6 h / day, and the waste collection module worked 5 min / day. The results showed that high stocking density had a negative impact on the growth performance and muscle quality of grass carp and blunt snout bream, and that the water quality in the culture tank gradually was deteriorated with the increasing stocking density. The economic benefits of different stocking densities in this system were investigated in this study, and grass carp high-density rearing failed to generate high benefits, but blunt snout bream high-density rearing leads to a higher income. The feasibility and rearing effect of the in-pond culture tank system were preliminarily confirmed. • A new type of in-pond tank culture system (IPTCS) was constructed. • The economic benefit of theIPTCS was analyzed.