Suspended net cage culture of juvenile Hemifusus tuba

Juvenile Hemifusus tuba were net cage cultured at different stocking densities(10,20,30,40,50 shells/cage) to select optimum stocking density and then cultured in suspended net cages in Yunbo bay,Yangjiang city,Guangdong Province.The juvenile H.tuba reared under different stock densities for 60 days in natural conditions showed an exponential growth in shell height and body weight.The coefficients of variance(CVs) for the growth of the juvenile H.tuba in all the treatments except D1(10 juveniles/cage) were significantly reduced.The juvenile H.tuba grew significantly different among the all the treatments,but fastest in the treatments D2(20 juveniles/cage) and D3(30 juveniles/cage).The growth rate,specific growth rate(SGR) and daily weight growth(DWG) of the juvenile H.tuba decreased with the increase of the stocking densities.The SGR had a significant cubic polynomial regression with the stocking density(SGR=0.857 3+0.153 2D-0.005 1D2+0.000 05D3,R2=0.999 1).Juvenile H.tuba in the treatments D2 and D3 grew the fastest in all stocking densities,but the D3(30 juveniles/cage) was the optimum stocking density and selected for net cage culture when the rearing cost and management were considered.The juvenile H.tuba were cultured in suspended net cages at the stocking density of 30 juveniles/cage in Yunbo bay.After 100 days of suspended net cage culture of the juveniles,the shell height increased by 34.7%,and body weight by 157.4%.The DWG and daily height growth(DHG) were 0.18 mm·d and 0.173 g·d,respectively.The survival rate was 98%.The suspended net cage culture is found fit for culture of juvenile H.tuba.