Technical points of stocking fish in winter with low water temperature and high survival rate

Releasing fish species in winter can not only improve the survival rate, but also promote preterm birth in early spring, make fish gain faster, make profits earlier, and increase income by 40% to 50%. The main techniques are:

Release fish fry in winter

First, the "five changes" in the pond. That is, small to big, shallow to deep, dead (water) to live (water), leakage (water) to protection (water), robbery (insurance) to flood prevention (flood). If there are conditions, build high-yield fish ponds to ensure good fish culture facilities.

Second, clear the pond and disinfect. It should be done on a sunny day. Pond cleaning method: first, dry pond cleaning (water depth of 10 cm), that is, 80 kilograms of quicklime per mu, or 4 kilograms of bleach containing 30% available chlorine. The second is to clear the pond with water (1 meter deep), that is, 150 kg of quicklime or 12 kg of bleach containing 30% available chlorine, dissolved in water and sprinkled throughout the pond. Fish seeds can be released only after 7 days of disinfection in the pond.

Third, fat water goes into the pond. After clearing the pond, apply base fertilizer, 250 kilograms of human and animal manure per mu (more can be applied in the new pond, less or no application in the fertilizer pond). After fertilization, winter water should be infused to cultivate natural bait.

Fourth, release early as appropriate. The Winter Solstice is a good season for stocking before and after the Spring Festival. As the saying goes, "fish species grow sharply when wax water is released." At this time, the water quality is stable, the fish is strong, the piece is tight, the activity is small, and the fish is not easy to be injured when people operate. At the same time, it is beneficial to prevent disease and promote the growth of fish as soon as possible.

Fifth, select fish species. To choose large fish, generally green, grass, silver carp, bighead carp, snout bream and other fish species should be up to 15cm long. It requires high back, fat tail, intact scales, intact fins, bright body color, no disease, no injury, and strong beating.

Sixth, strict disinfection. Before stocking on a sunny day, the fish should be trained and disinfected by pulling the net, and the fish can be soaked in 3% salt water for 15 minutes. If there are conditions, 0.5 milliliters of diluted green and grass carp hemorrhagic inactivated vaccine can be injected into each fish of more than 18 centimeters, and 0.3 milliliters of each tail shall be injected to prevent and cure the haemorrhagic disease.

7. Reasonable delivery. The pond with fat water quality should be dominated by silver carp, and the proportion of mixed culture: silver carp 45% 60%, bighead carp 5%, grass carp 10%. 10% of carp, 10% of crucian carp, 10% of carp, 10% of carp and 5% of carp. Ponds with thin water and more green fodder should mainly be grass carp, and the proportion of mixed culture: grass carp 45% 55%, silver carp 20%, bighead carp 5% 10%, crucian carp, etc. 10% 5% each, and the amount of stocking per mu is about 1000.

Eighth, strengthen management. After the fish are released, the water depth should be more than 2 meters to prevent freezing. After the water temperature rises more than 6 ℃, bait should be given properly to promote the early growth of fish species.