Experienced culturists grow species appropriate for their regions, growing season, and markets. Yields from culture ponds can range from a few hundred to several thousand pounds per acre, depending upon fish density, feeding rate, and skill of management. High quality water continuously flows into the holding unit. It passes through the heavily stocked unit and is discharged when quality is no longer suitable for good survival and growth. Treatment of discharge waters should be incorporated into a flow-through system.
Yields are dependent upon water flow, aeration, and water temperature.
If suitable elevation differences are available, a series of flow through systems can be linked together. Each raceway receives the discharge water from the preceding unit. Part of the water may be passed through a biological filter, where waste products are detoxified by bacteria before the water flows to the next rearing unit. Reuse systems must be designed and operated carefully to function effectively. Also, care must be taken not to transfer disease problems between units.