Overwintering and disease control of shrimp

Overwintering of green shrimp is an important part of green shrimp culture, and the prevention and control of shrimp disease is an important measure to improve the benefit of green shrimp culture.

Overwintering monitoring of green shrimp

1. Green shrimp overwintering:

Green shrimp overwintering is divided into juvenile shrimp overwintering and parent shrimp overwintering. Juvenile shrimp refers to the shrimp that propagates from August to September and does not reach the commercial specification by December, overwintering and leaving it for release from March to April of the following year, while the parent shrimp is selected to survive the winter safely and strengthen its cultivation to meet the requirements of spawning and reproduction. Therefore, to do a good job of overwintering green shrimp is an important part of breeding green shrimp.

(1) choose the method of overwintering and make preparations:

Green shrimp overwintering can be used in ponds or cages. The use of ponds for the winter, choose a more regular, shelter from the wind and the sun, water depth of more than 1.5 meters, more water plants of the pond. Cage overwintering, in addition to choosing a good cage, but also choose a deeper water level, less wind and waves, micro-flow river, Hong Kong branch to set up cages. The green shrimp overwintered for as long as 4 months from December of the first year to March of the following year. During the overwintering period, green prawns generally lurk in the aquatic plants at the bottom of the pool or box, with little activity. In order to provide a good warm environment for green shrimp overwintering, 150 kilograms of water and grass and 25 kilograms of willow root should be put in the pond, and the cage depends on the situation.

(2) reasonable stocking to improve the survival rate:

The overwintering parent shrimp should choose the prawns with strong physique, complete appendages and standard body shape, and the female parent shrimp should be 200 million / kg. The male is 140,150 / kg, and the ratio of female and male shrimp can be matched at 2:1. After the parent shrimp is selected, it can be put into 15,25kg per mu of pond or every 70 square meters of cage. Young shrimp overwintering, each mu of water or 70 square meters of cage put a specification of 2000 million 3000 / kg of 20 million 40 kg of young shrimp. Usually in mid-December, late December began stocking, choose sunny and warm weather stocking, in order to improve the survival rate.

(3) to take bait scientifically and improve the management system:

Parent (juvenile) shrimp still need a small amount of food in order to maintain their life and vitality during the overwintering period. For this reason, during the whole overwintering period of green shrimp, it is necessary to persist in feeding, usually in sunny and warm weather, feeding 1 kilogram of commercial bait per mu of water or every 70 square meters of cage, once every 7 to 10 days, so as to ensure that the parent (juvenile) shrimp can survive the winter safely. Special personnel should be designated to patrol the ponds regularly, check the overwintering condition of parent (juvenile) shrimp, and do a good job in preventing pollution, caisson, enemy damage, and so on. In the severe winter season, it is also necessary to prevent pond water from freezing. Once found, it is necessary to break or drill holes in time to prevent parent (juvenile) shrimp from asphyxiation due to lack of oxygen, so as to make parent (juvenile) shrimp survive the winter safely.

Second, disease prevention and control of green shrimp:

Green prawns have strong disease resistance and less disease. However, if the bait is not managed properly, disease is also inevitable. The main diseases of shrimp are Gill rot disease and red body disease.

(1) rotten Gill bacteria: the Gill filaments of diseased shrimp are black and the director is moldy. Prevention and cure method: prepare according to the dosage of 2 grams of bleach per cubic meter of aquaculture water, dissolve in the water and sprinkle it in the whole pond. In order to ensure that the dissolved oxygen in the pond (box) is more than 4.8 mg / L, the residual bait and dirt in the pond (box) should be cleaned to keep the culture environment safe, so as not to pollute the water quality and cause Gill rot disease of green shrimp.

(2) Red body disease: at the initial stage of the disease, the tail stalk of the diseased shrimp is red in color, then the red gradually reaches the whole abdomen, and finally affects the head and chest and dies. The disease mostly occurs 1-3 days after seedling throwing, field removal and selective capture, and is mostly caused by poor operation. Prevention and treatment: give priority to prevention, once it occurs, the drug has no obvious effect. Preventive measures: in the operation, the action should be light, work with water, and do not stack and oppress the green shrimp. Try to keep the prawns intact and undamaged.