Tilapia are tropical fish that are not resistant to low temperature and will gradually die when the water temperature drops below 12°C. Under normal circumstances, in addition to a few areas in southern my country, tilapia can naturally overwinter, other areas need to take measures to help overwinter. According to the practical experience of production, there are several safe wintering methods for tilapia.
1. Hot spring water overwintering.
The area of the wintering pond should be determined according to the water temperature, flow, terrain and production scale. The water depth of the wintering pond should be 1.5-2 meters, and the water inflow and outflow should be similar to maintain a certain water temperature and depth. If the water temperature of the hot spring is very high, it should be cooled to a certain temperature by the reservoir first and then injected into the overwintering pool. This overwintering method and overwintering density are high. At the same time, due to the high water temperature and sufficient water, the breeding and cultivation of broodstock can be strengthened, the gonads of broodstock can be promoted, and the breeding and seedlings can be carried out in advance.
Tilapia
Tilapia
2. The remaining hot water in the factory can survive the winter.
Use the cooling water discharged from some factories to overwinter directly in cooling pools or build overwintering pools. The area of the wintering pool is determined according to the temperature and flow of the cooling water, and the water depth is preferably 1.5-2 meters. The waste steam from some factories can also be used to adjust the water in the temperature-adjusting pool as required, and then pass into the wintering pool to keep warm and overwinter. This overwintering method can make use of heat source conditions according to local conditions, with low cost and good overwintering effect.
3. Overwintering in earthen ponds with plastic sheds.
The wintering pond is selected in a leeward and sunny place, with good water quality and convenient water and electricity. The winter pond is best to choose east-west, rectangular, with an area of 60-120 square meters, and a water depth of 2-2.5 meters, which is convenient for injection and drainage. An arched or herringbone-shaped scaffold is built with steel bars or bamboo and wood on the pool surface. The height of the roof is 1.8-2 meters above the ground, and it is covered with two layers of plastic film. This wintering method can use groundwater as the water source and keep the water temperature at 16-18°C. The wintering effect is good, the cost is low, and it is easy to popularize. If there is no groundwater, water from reservoirs and streams can be used to heat the water through electric heaters to increase the water temperature. Generally, 30 cubic meters of water should be equipped with 1-2 electric heaters of 3 kilowatts. This method is suitable for small-scale farmers to overwinter.
