Cage culture technique of grass carp

Grass carp cultured in cage should choose places with leeward, open water, stable water level, fresh water quality, non-pollution water source and convenient transportation, which requires rich dissolved oxygen, pH 7.0-8.5, water depth 4-5 meters, water transparency above 50 cm, dissolved oxygen about 5 mg / L, and complete water conservancy facilities in the culture area, which can be discharged and irrigated, and is not easy to be affected by flood. Let's take a look at the cage culture technology of grass carp.

The configuration method of net cage

1, cage equipment: the cage should be made of polyethylene mesh, double-layer structure, cage specifications can be 5 m × 5 m x 3 m, cover net is single layer, eye size is 5 cm, 3 × 4 lines, bottom net and side net inner mesh is 3 cm, 3 × 4 lines, outer mesh is 4 cm, 3 × 6 lines.

2, cage installation: the cage is set according to the "non" type, one end is fixed on the river bank, and the other two corners are fixed with concrete blocks weighing 100 kg respectively. The support of the cage is 6 meters long and 40 mm in diameter. Galvanized steel pipe and wire weighing 13 kg ~ 14 kg are tied to the oil barrel, and a mineral water bottle containing 2 kg of sand and stone is placed on the four corners of each cage. The distance between each cage is 1 meter, and the water depth of the cage is 2 meters.

3. Set up fence: the cage should be installed 7 days before the fish is put into the box, so that the net coat is attached to algae, so that the net is smooth, and the net coat is avoided to scratch the fish after entering the box. The cage arrangement direction should be perpendicular to the direction of water flow. In order to prevent sundries from damaging the cage, fences should be set up outside the aquaculture waters.

Stocking methods of fish fingerling

1, the fish species should be excellent: the fish species require strong physique, neat specifications, complete scales and fins, disease-free and injury-free, and large fish species of more than 20 centimeters should be put when releasing fish.

2. Appropriate density: grass carp in general cages are 300-500 grams per fish, and about 20-25 fish per square meter. Silver carp, bighead carps and blunt snout bream species with specifications of 200-300 grams per fish can be cultured in the cage.

3. Pay attention to methods: before entering the box, fish should be bathed and disinfected to kill body surface parasites. They can be soaked in 3% 5% salt water or 20 grams of potassium permanganate per cubic meter for 15 minutes. The stocking period is usually in late autumn or early winter, and it is better when the water temperature is about 15 ℃. At this time, grass carp can still eat after entering the box, and there is a recovery period, which can start eating early after the beginning of spring, increase the growth time of fish and lay the foundation for high yield and high efficiency.

Management of feed feeding

1. Feed selection: when grass carp are cultured in cages, grass should not be fed in large quantities, because insufficient nutrition of grass can not promote growth, so full-price pellet feed should be fed to improve feed utilization rate and reduce water pollution caused by residual bait.

2. Feeding method: grass carp can be domesticated and fed two or three days after entering the box. The daily feeding amount is 3% of the total body weight of grass carp, three or four times a day, 0.5 hours-1 hour each time, to the extent that most fish are full. The feeding method should pay attention to the "four fixed" principle, bait should be sprinkled with a small handful, and then the second one should be sprinkled with a small hand. when the food grab is not fierce, you can cast a small amount slowly. So that weak fish can also eat feed to ensure their balanced growth.

3. Strengthen feeding: grass carp grow fastest when the water temperature is 25 ℃-30 ℃, and the feeding amount should be increased. In rainy, muggy, thunderstorm and other bad weather, feeding should be reduced or stopped. The green feed can be fed once every night after disinfection with 1% bleach, and the feeding amount shall prevail on the second day without leftover grass.

Daily management of grass carp

1. Adhere to the box patrol: we should patrol the boxes every day, check the growth of fish regularly, reasonably adjust the amount of feeding, carefully observe and analyze the fish situation, and deal with problems in time. Wash the cage once every 10-15 days to remove the residual bait dirt and attached algae, so that the water body is fully exchanged.

2. Check the box regularly: check the cage frequently and repair it in time to avoid escaping fish or ferocious fish into the box. In the flood season, it is also necessary to check the strength of the rope, whether the cable is firm, whether the net clothing is deformed, and so on.

3. Adjust the box frequently: with the fluctuation of the water level of the reservoir, the cage must be adjusted to the position of suitable water depth and water quality.

Prevention and control techniques of fish disease

1. Prevention first: it is necessary to adhere to healthy breeding, operate according to regulations, prevent diseases before they occur, do a good job in prevention and do a good job in artificial immunity, generally inject inactivated vaccines against "three major bacterial diseases" of grass carp and inactivated vaccine against grass carp hemorrhagic disease before entering the box, disinfect fish with salt water before entering the box, and regularly disinfect and prevent diseases. Feed Chinese herbal medicine baits such as Fish Disease Kang every 10 days or so for three to five days. To prevent bacterial fish disease.

2. Purify the water quality: every 10-15 days, each cage is sprinkled with 250-500 grams of quicklime pulp while it is hot to purify the water quality.

3. Disinfection and sterilization: every month, insecticides and fungicides are sprinkled in the whole box. In high temperature season, detoxification and sterilization can be done by hanging bags around the cage. The mixture of bromochlorohydantoin, copper sulfate and ferrous sulfate can be selected for timely prevention and treatment of water mildew, red skin disease, Gill rot, enteritis and hemorrhagic disease.