Maintain appropriate culture density
固﹒
As fish grow, they need more space for movement. Since the space in a net cage is linnited, it is necessary to make adjustment according to the size or weight of fish stock. Failing this will weaken the immunity offish and result in higher risk of injury caused by fish knocking against each other as well as bacterial, viral or parasitic infection. Another risk associated with high stocking density is that dissolved oxygen may be insufficient to sustain the entire stock. This is particularly common when water level is too low and water current is poorly exchanged or stagnant. The fish stock may su仟er from anoxia. Moreover, fish waste may also encourage growth of bacteria.