Technical Key Points for Constructing Flow-Through Aquaculture Ponds for Yellow Catfish

1) Water quality and water source

1. Water quality requirements The water quality for flow-through aquaculture of yellow catfish must be tested before deciding on the aquaculture operation, to see whether the water quality meets the pollution-free aquaculture water quality standards. For example, whether the waste hot water discharged from industrial production has been polluted by industrial oil, etc., and whether the minerals contained in underground hot spring water exceed the standard, are all objects of attention.

2. Water source requirements The water source for flow-through aquaculture of yellow catfish must be sufficient, and the water supply will not stop due to human or natural factors. If it is industrial waste hot water or underground spring water, while considering sufficient water source, it is best to have a backup water source; for building flow-through ponds using river flow, attention must be paid to the impact of drought or floods and rainstorm periods on the water used in the fish ponds.

2) Fish pond construction

1. Fish pond shape The fish ponds for flow-through aquaculture of yellow catfish are mainly cement ponds, and the fish pond shape is mostly rectangular, though of course there are also circular, oval and other irregular shapes. Determining the pond shape should proceed from reality, so that the water flow in the fish pond can flow smoothly everywhere, that is, there are no dead corners where the water cannot reach.

2. Area size The fish pond area requirements for flow-through aquaculture of yellow catfish are not very strict, but considering that the flowing water can flow smoothly throughout the pond, the general single pond area is about 40-400 sq m.

3. Fish pond layout When carrying out standardized, batch-type flow-through aquaculture of yellow catfish, the number of fish ponds is relatively large, and at this time the layout of the fish ponds must be considered. Fish pond layouts include contiguous type, series type, parallel type and other forms.

4. Inlet and drainage systems The construction of the inlet and drainage systems is the core content of flow-through aquaculture of yellow catfish, including inlet and drainage channels, water ports, escape-prevention grates and sewage discharge systems, etc.

(1) Inlet system In industrial warm flow-through aquaculture using factory waste hot water and aquaculture using underground hot spring water, it is required that the distance from the inlet channel to the fish pond not be too far, so as to avoid excessive release of the water's heat energy. Inlet methods include overflow type, direct-jet type, scattered type, water-curtain type and spray type, etc. Each place should proceed according to its own circumstances, adapt measures to local conditions, and apply them flexibly.

(2) Drainage system The drainage system consists of two subsystems: drainage and sewage discharge. The drainage outlet can be a culvert gate type, or a self-flow type with a limited water level. As for sewage discharge, it is for discharging the fish excrement and leftover feed at the bottom of the pond. Generally, the bottom of a rectangular fish pond has a slope of 1/200-1/100 from the inlet end to the outlet end. When the diameter of the drainage and sewage discharge pipe openings is above 10 cm, it has a relatively large suction force and can discharge the sewage. The drainage outlet, like the inlet, must have a special grille to prevent yellow catfish from escaping, as well as facilities for adjusting and controlling the water level.