Strengthening the management techniques of parent fish cultivation and aquaculture in winter

Parent fish

The autumn and winter season is in the early stage of gonadal development of parent fish, the quality of parent fish cultivation at this stage is directly related to the number of eggs of parent fish next year, and also determines the success or failure of artificial reproduction of parent fish in the following spring, so it is very important to strengthen the cultivation of parent fish in autumn and winter. The key technologies are:

1. Look at the water and fertilize

Silver carp and bighead carp feed on plankton and promote the proliferation of plankton through fertilization to meet the needs of gonadal development of parent fish. If the bait is sufficient, the gonadal development is good, so fertilizing according to the water is the key to raise the color of silver carp and bighead carp. Especially before winter, it is necessary to strengthen fertilization (usually about 500KG per 667M2 per week) to make the water color thicker. If the water quality is not fat before the beginning of winter, the cold current of frost will suddenly make the water lighter, which will not achieve the purpose of cultivating silver carp and bighead carp. At the same time, a small amount of fertilizer should be applied after winter, and the principle of "a small number of times and continuous replenishment" should be followed when applying fertilizer. Fertilizer must be rotten manure, do not apply raw fertilizer, it is best to compost water. It is worth noting that when there are thundershowers and muggy low pressure in autumn, the amount of fertilization should be strictly controlled and not fertilized as much as possible, so as not to cause parent fish flooding the pond. In short, it is necessary to store sufficient nutrients for parent fish in autumn and winter to ensure the normal development of their ovaries at the beginning of spring. The cultivation of parent fish of silver carp and bighead carp mainly grasps normal fertilization in autumn and winter, and sufficient organic fertilizer is applied in winter. Human manure accounts for about 70% and livestock manure accounts for about 30% in parent ponds dominated by silver carp and bighead carp. Loach ponds are mainly cow dung, accounting for about 70%, and human manure accounts for 30%.

two。 Reasonable bait

Because the feeding habits of grass carp and herring are different from silver carp and bighead carp, there are also differences in their cultivation methods. Reasonable baiting is the key to cultivate good relatives of grass carp. In autumn and winter, due to the decrease of water temperature, the feeding intensity of grass carp decreases gradually, and the source of green feed is also relatively inadequate. during this period, we should feed soybean cake, wheat bran, corn and other concentrate to strengthen cultivation. In order to promote the feeding and digestion of parent fish, concentrate and green feed should be fed separately, generally feeding green feed in the morning, accounting for 30%-50% of the body weight of parent fish, and concentrate feed in the afternoon, accounting for 2%, 3% of the body weight of parent fish. After entering the winter, the feeding amount of concentrate decreased. Generally, it is fed every other day when the water temperature is high, and once every 3 days when the water temperature is low. Herring to feed snail, clam, meat, supplemented by a small amount of bean cake and other refined feed, but to eat for the degree.

3. Timely water injection

Adding fresh water and keeping the pond water fresh is one of the technical measures to promote the gonadal development of parent fish. At the same time, deepening the water level in autumn and winter can maintain the water temperature. in general, the injection of new water should be flexibly controlled according to the season, air temperature, fat and thin water quality and parent fish feeding. In autumn and winter, the water level is generally flushed every 15-20 days for 3-5 hours, which increases the water level by about 20cm, but it should be noted that the flushing of silver carp and bighead carp parent ponds should be less.

4. Timely disease prevention

The prevention and treatment of fish disease should follow the policy of "no disease first prevention, early treatment of disease", generally disinfect the food farm every 15 times, such as disinfecting with bleach, its dosage is 0.5-0.75KG. At the same time, the residual bait and residue of the food farm should be removed regularly. Strengthen pond patrol and timely diagnosis and treatment of fish diseases.