Key points of cultivation techniques of parent fish in winter

The cultivation of parent fish can be divided into postpartum nursing, autumn cultivation, winter cultivation and spring cultivation. Due to the low temperature in winter, the activities of parent fish are reduced, the feeding ability is weak, and fish diseases are easy to occur. If it is poorly managed, it will have a great impact on artificial hatching, fry production, adult fish culture and other production links in the coming year. The main technical points of cultivating parent fish in winter are as follows:

I. Pond selection

The parent fish pond requires adequate water source, flat bottom, shelter from the wind and sun, water conservation and heat preservation, with an area of 10 murals and 15 mu.

2. Rational stocking

The stocking density of parent fish is that it can not only make full use of water body, but also make its gonad develop well. Reasonable stocking density is an important condition to ensure the success of parent fish cultivation. The requirements of different varieties are:

In the ponds where silver carp parent fish are mainly raised, there are 15 fingerlings with a tail weight of 5kg per mu, 5 bighead carp with the same specification, and 5 grass parent fish with a tail weight of about 10kg. In the ponds where bighead carp parent fish are mainly raised, there are 15 breeding fish with a tail weight of 15 Mel 20 kg per mu, and 5 grass parent fish with a tail weight of about 10 kg. In the ponds where the main grass parent fish are raised, there are 15 grass parent fish of 10 kg per mu, 3 parent fish of silver carp or bighead carp and 12 kg of snout bream per mu. The female-to-male ratio is generally 1: 1. 5, and the lowest is not less than 1:1.

III. Daily management

Fish ponds should be managed and carefully managed by special personnel. Regularly patrol the pond, regularly add new water to increase dissolved oxygen, prevent leakage, maintain a certain water level, in order to increase the temperature of the water body. When the weather is sunny and the water temperature is above 6 ℃, it is necessary to feed an appropriate amount of concentrate and green feed for direct feeding of fish to strengthen their physique and reduce weight loss. For the ponds which mainly raise silver carp and bighead carp, some fermented manure should be put regularly during the whole overwintering period in order to increase the water temperature and improve the water quality.

IV. Prevention and treatment of fish diseases

In winter, parent fish are easy to get water mold, white skin and other fish diseases, we should pay attention to brisk action when catching parent fish, avoid harming the skin and scales of fish; do not use the fish with severe mechanical damage as parent fish in the coming year. Water mildew can be treated with Weikang immersion of 10-20ppm or sprinkled with Weikang 0.15-0.3ppm.