Pond promotion of river crab technology promotion

First, materials and methods

1, crab pond selection: generally 8-10 acres is appropriate, the pond is mostly rectangular, east to west, slope ratio of 1:2.5 (or 1:3), pool depth of 1.5-2m, water is groundwater, water quality is good, The environment is quiet, and the subsoil is clay loam, which is impermeable to water, electricity, and access.

2. Place aquatic plants and transplant various aquatic plants, accounting for 30% of the aquaculture area, of which submerged plants account for 1/3 of the total area, and floating plants account for 1/3 of the total area.

3. Construction of anti-escape facilities: The crabs are not only easy to escape during the migratory migration, but also easily escape. Therefore, it is necessary to build anti-escape walls with better anti-escape ability. According to their own environment, water conditions, divided into the following methods:

1Cement board anti-escape wall, made of cement and steel plate, each piece of cement board is 1-1.5m thick, 0.8-1m high, 0.05m thick, buried along the crab pond, with a wall height of 0.5-0.6m, buried in soil 0.3 -0.4m.

2 The red bricks prevent escape from the wall, use ordinary red bricks, follow the walls of the pool along the crab pool pool, the wall base is buried 0.3-0.4m, the wall height is 0.5m, and the side near the crab pond is plastered with cement or a layer of flat glass. To enhance anti-escape performance.

3 Asbestos tiles, plastic films and other materials can also be used to prevent escape.

Second, before the crab preparation and breeding process

1, cleaning and disinfection

Crab pond 15-20 days before stocking, use quicklime or bleaching powder, the amount of 65-75kg per acre, after dissolving the whole pool spilled clear pond, clear pond after the complete disappearance of toxicity, livestock and poultry manure applied per acre 800-1000kg, training Fertilizer quality, inject new water.

2, put the crab species

The amount of crab species to be stocked differs depending on the mode of farming, the species of crab, and the level of rearing and management. Each mu has a volume of 20-30 kg, and the size is 100-200 kg/kg. The stocking time is mid-April, and the water temperature is 15°C or higher. should.

3, feeding

Before mid-June, animals were fed animal feed (such as small fish, snails) and plant foods (corn, wheat, potatoes, all kinds of water grass), the ratio of 3:2, in mid-August in late June was 9: During the period from November to September, the crabs were fattened, and corn, potato and other foods containing sugar and starch were increased and no animal feed was added. More vote in sunny days, less rain in the rain; found that the remaining bait should reduce the amount of bait, twice a day, in the morning to feed 30% of the total amount of the day, night feeding 70% of the total amount of the entire day.

4, water quality regulation

The optimum water quality for crabs, dissolved oxygen is above 5mg/L, PH value is between 6.8 and 8.7, and the transparency is about 30-50cm. Before the beginning of May, the water level is kept at 0.6m to increase the water temperature, and the water level is maintained at 0.8-1m before early July. In early July, the water level should be maintained at 1.5m. The water should be replaced once every 5 to 10 days from June to September. The water should be changed once every two weeks in spring and autumn. Each time the water is changed to 1/3, the water should be discharged first.

5, disease prevention

1 Dredging and disinfecting with limed dry ponds 2 Planting plants and transplanting snails 3 Seed quarantine and disinfection 4 Regulation of water quality and improvement of substrate quality.

Third, daily management

1, patrol pond

The patrol ponds were conducted once in the morning, in the evening and in the evening to check the crabs for feeding activities and changes in water quality.

2. Anti-escape

Check whether the anti-escape facilities are in good condition and find that the problems are repaired in time.

3, do a good job of flood control, wind work, ready flood control equipment.

4, to eliminate the enemy

There are mainly waterfowls, frogs, water mice, etc. They should be caught and killed by drugs such as squirrel cages.

Fourth, fishing harvest

In October-November, cages were mainly arrested, supplemented by light trapping and dry pond catching.

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