Detailed Explanation of Key Points of Off-Season Crayfish Farming Technology

AbstractFarming pond: Choose a pond facing the sun and sheltered from the wind, dig several strip-shaped trenches of the same size in the pond, clean the pond bottom, filter the water and fill it, then plant water hyacinth and other aquatic plants, and finally install a microporous aeration pipe in the strip-shaped trenches. Shed frame: Two layers of thick plastic film need to be covered on the built shed frame. Stocking fry: Fry can be stocked in mid-to-late November, with about 50 kg of semi-commercial shrimp stocked per mu. Feeding: Feed once a day, and make sure the dissolved oxygen content in the water is sufficient.

Crayfish begin to live in burrows when the water temperature is below about 12°C and no longer come out to forage. At this time, crayfish are difficult to catch, and the market will be in short supply. Therefore, mastering off-season crayfish farming technology can achieve good economic benefits.

1. Choosing a Farming Pond

The farming site can be a pond facing the sun and sheltered from the wind, generally rectangular with the long side running east-west, with convenient water inlet and drainage. Slightly hard loess soil can be used, and a small amount of aquatic plants can be planted in the pond.

2. Building the Farming Pond

1. Dig several strip-shaped trenches of the same size in the pond. They need to be rectangular with the long side running east-west. The trench ridges should be 50 cm above the water surface, the ridge top width should be 40 cm, the strip-shaped trench width should be 5 m, the length should be 40 m, the trench depth should be 50 cm, and the slope ratio should be 1:1.2.

2. The pond bottom needs to be leveled and the silt removed. After filtering the incoming water, fertilize it and plant water peanut, Elodea, water hyacinth, and other aquatic plants. Finally, install a microporous aeration pipe in the strip-shaped trenches to help with aeration.

3. Installing the Shed Frame

1. Use a knife to shave off the knots and thorns from the moso bamboo prepared for tying the shed, then insert it into both sides of the trench ridges of the strip-shaped trenches at a spacing of 2 m. Bend the moso bamboo on both sides and tie it firmly with tape so that it forms an arch. Place crossbeams on the arched moso bamboo and tie them firmly with tape to strengthen the sturdiness of the arch frame.

2. In the center of the strip-shaped trench, from east to west, use moso bamboo to drive stakes and lay a bamboo board path, which is convenient for later feeding and catching in the shed. The bamboo board path should be 10 cm above the water surface. Then cover the shed frame with two layers of thick plastic film to help with heat preservation. During this period, both ends of the strip-shaped trench can be enclosed with plastic film, leaving a small door for convenient entry and exit.

4. Stocking Broodstock

After all the preparatory work for the farming pond is done, on November 20, stock semi-commercial shrimp at 40-50 shrimp/kg, with 50 kg stocked per mu. Before stocking, they can be disinfected with 3%-5% salt water, and then evenly placed along the strip-shaped trenches onto the aquatic plants in the farming pond.

5. Feeding Management

1. Entering November, because the light intensity becomes weaker and the air temperature gradually decreases, the water temperature inside the greenhouse also begins to decrease. During this period, feed once a day, with a feeding rate of 3%-4%. Feeding can be chosen at noon when the temperature is relatively high. The management method is the same as normal farming management.

2. However, the greenhouse is relatively tightly closed, so it easily leads to oxygen deficiency in the water. During this period, the microporous aerator should be turned on frequently for aeration to ensure that the water body in the shed has sufficient dissolved oxygen. On sunny noons, the small doors at both ends of the greenhouse also need to be opened for ventilation, which helps increase the oxygen content in the shed.

3. At night when there is no light, a layer of straw curtain can be covered on top of the greenhouse, which helps increase the temperature inside the shed. Because closed feeding is carried out, the water body farmed in the shed also flows relatively little, so water quality is easily spoiled. During this period, biological agents can be used to regulate water quality.

6. Catching and Selling

When farmed until before the Spring Festival, the market for crayfish will be relatively good. At this time, catch and sell the large-sized crayfish. The average yield per mu can reach about 80 kg, the output value per mu can reach about 5,600 yuan, and the net benefit of a 20-mu pond is about 64,000 yuan.