Fish and clam mixed culture with high efficiency

The experiment of mixed culture of fish and clam in pond was carried out in 2004, and good economic benefit was obtained.

I. Test materials

1. For the preparation of culture ponds, two standard ponds excavated by low-lying fields have been excavated for three years, with a total area of 10.2 hectares, pollution-free, sunny, ventilated, north-south, rectangular structure and an average water depth of about 2 meters. The utility model has the advantages of convenient intake and drainage, sufficient water source and good water quality.

two。 One week before disinfecting fish and clams in clear ponds, choose a sunny day, clear the ponds with 75 kg of quicklime per mu of water depth, and put 200 kg of fermented chicken manure per mu to cultivate good water quality. Fish species should be strictly disinfected before stocking, nets and various tools should be used in special ponds, and the food farm should be disinfected regularly with bleach.

3. In February 2004, 1000 2-year-old Hyriopsis cumingii, which were physically strong and disease-free, were hoisted and reared per mu. The method of hanging net clip was used in the culture of pearl mussel. In a polyethylene flat mesh clip with a size of 15 cm × 40 cm and a mesh of 3 cm × 3 cm, the pearl clam axe foot is lowered, and 3 birds are kept in each net clamp. generally, the net clip is hung in the water about 15 cm below the water surface in spring and autumn, and in the water about 35 cm below the water surface in winter and summer.

4. In late February 2004, 20 strong silver carp, 30 silver carp, 20 grass carp and 50 crucian carp were released per mu, 150 white fish and 120 flower bones per mu in April of the same year, 10 mandarin fish (body length 2.5 cm) and 0.75 kg of large size egg-holding shrimp per mu in May of the same year. Among them, mandarin fish and shrimp with eggs are put once a year.

2. Feeding and management

1. Bait fertilization at the inlet of the pool with a dense mesh to the ridge of the pond as one side, the distance is 1 meter parallel into a circle, the circle is used to stack fermented organic fertilizer. In the low temperature season, timely input of partially fermented manure, mainly chicken manure, fertilization a small number of times, generally twice a month. Apply chemical fertilizer from March to August with high temperature, adhere to the principle of a small amount and many times, generally use 1 kg of urea and 3 kg of superphosphate per mu. The transparency of the pool water is controlled at about 25 cm. The white fish and flower bone are fed and domesticated manually with special pellet material for white fish, and the protein content of the pellet material is more than 35%. The bait adheres to the principle of "four fixed". When the weather is normal, pellet feed is given twice a day, once at 8: 9 a.m. and 4: 5 p.m., in rainy days or low pressure; if the weather is muggy, the feeding is postponed or stopped, and the daily feeding rate is controlled at 5% of the fish's body weight in the early stage and 3% in the later stage.

two。 Timely irrigation often keeps the pool water in a micro-flow state. Generally, the water is flushed every 10 days, and the water exchange capacity is required to reach a depth of about 50 cm. In summer and fish and clam disease season, the water is changed every 7 days to make the water "fat, alive, tender and cool".

3. After frequently applying quicklime to 15 kg / mu of calcareous water per month, it should be sprinkled once in the whole pool (not on the net cage). From May to September, it is required to sprinkle 2 times per month. If there is a large area of green algae in the water body, the application of quicklime will be suspended.

4. Make a timely inspection and make a good record on the basis of patrolling the pond in the morning and evening, sampling inspection of the pearl clam once a day, turning the pearl clam regularly, so as to prevent the yin and yang side of the pearls on the left and right sides and the clam shell from getting stuck into the net line. and remove the attachments on the net cage in time. In the season of high incidence of mussel disease, check in time, fish out the dead clam and take out the pearls in order to reduce the cross-infection caused by dead clam disease.

III. Results

The total investment was 1.123 million yuan (including 206500 yuan for pond rent, 495300 yuan for mussel, 48500 yuan for fish species, 156000 yuan for feed and 125000 yuan for employees' wages), the total output value was 1,883,500 yuan, the total profit was 760,500 yuan, and the input-output ratio was 1 ∶ 1.68 yuan. The harvest of fish and mussels is shown in Table 1.

Table 1 the harvest of fish and clam

Name pearl clam mandarin fish white fish flower bone green shrimp other

Output (kg) 18152617151253050158916530

Survival rate (%) 83958792

Output value (ten thousand yuan) 119.86.5533.289.156.3513.22

IV. Experience

1. The structure of fish stocking and collocation should be reasonable. Mixed culture of fish and clam is a culture mode dominated by pearl clam. The total production of fish should be controlled, and the yield of conventional fish should be less than 150 kg per mu. In fish species, silver carp and pearl mussels have similar feeding habits, so they should be released less appropriately. Herring, blunt snout snout bream and carp can easily lead to rotten axe foot disease of pearl mussels. It is a good exploration and development direction to optimize the mode of mixed culture of fish and mussels by raising new varieties such as white fish and flower bones, and feeding pellet feed, but the growth rate of white fish and mackerel in Bengtang is slower than that in specialized ponds, and the utilization rate of pellet feed is low.

two。 Frequent application of quicklime calcium is an indispensable substance in the process of pearl growth. After March, pearl clam begins to lay eggs and apply more quicklime, which can inhibit its reproduction and is beneficial to the formation and growth of pearls.

3. According to the growth of fish and shrimp, ground cage and shrimp cage can be used to catch fish on the market at the right time. On the one hand, the seasonal difference of fish price can be used to improve economic benefits, on the other hand, it can reduce the culture density and promote the growth of fish and mussels.