Growth Characteristics of Epinephelus septemfasciatus and Epinephelus moara in Recirculating Aquaculture Systems (RAS)

Abstract:

Seven-band grouper (Epinephelus septemfasciatus) and Kelp bass (E.moara) grow fast and are considered to have great commercial potentials in marine fish cage culture in the temperate seas along the coast of Northeast Asia. There have been extensive aquacultural studies on these two species internationally in the past several decades. This study focused on the mass seed production technique of E.septemfasciatus and E.moara in China, which was newly developed in recent years. Recirculating aquaculture system (RAS) provides a stable environment for the fish growth that is not affected by natural conditions, hence has been the major breeding mode for a sustainable development in the aquaculture industry. In this mode one can easily compare the growth characteristics of different fish species. In this study we used curve estimation to analyze the model and to estimate the parameters for the growth of E.septemfasciatus and E.moara. Their growth was characterized based on the weights, the total lengths and the body lengths. After the 122-day culture, the average weights of E.septemfasciatus and E.moara increased from (114.836±25.343) g to (213.861±38.604) g and from (79.620±13.007) g to (238.086± 46.307) g respectively. The total lengths (TL) of E.septemfasciatus and E.moara could be described by functions TL=−0.006t3+1.622t+13.954 and TL=−0.013t2+2.008t+11.540 respectively, in which the variable t was the culture time. The relationship between the weight (W) and the body length (BL) of E.septemfasciatus and E.moara conformed to W=0.436BL2.055 and W=0.018BL3.083 respectively. The relative growth rates (RGR) were 0.707% for E.septemfasciatus and 1.631% for E.moara. E.septemfas-ciatus and E.moara did not show significant difference in the relative fatness (2.2−3.4, P>0.05).