Experience of rotational culture of mandarin fish and green shrimp

Mandarin fish and green shrimp are the best-selling varieties in the market at present, with high demand, high price and high breeding efficiency. The rotation culture of mandarin fish and green shrimp in the pond can maximize the idle period of the fish pond, give full play to the water and bait resources, increase the output and greatly improve the production benefit of the pond.

I. Pond conditions and preparation

1, the area of the pond requires that the area of the pond is 3Mu, oblong, the ratio of length to width is 2.5mm, the east-west direction is better, the width of the pond ridge is 3mur5m, the slope ratio of the pond is above 1:3, and the bottom is flat and slightly inclined to the drainage side, which is convenient for fishing in the draining dry pond.

2. The depth of water is l.2-l.5 meters, which is beneficial to the growth of aquatic plants, photosynthesis, the supplement of dissolved oxygen and the habitat, feeding and growth of shrimp and fish.

3. The water quality is fresh and pollution-free. The dissolved oxygen in the water is above 4mg/L and the PH value is 7.5.

4. the separation of drainage and irrigation is beneficial to the regulation and control of water quality and the prevention and control of diseases, and the water quality of the source is fresh and pollution-free.

5. the pond transformation of the mandarin fish dry pond is over, and the ditch which is 2 meters wide and 0.5 meters deep is excavated in the pond, and the ditch connected with the drainage ditch is used as the shrimp collection trough, which is convenient for fishing in the dry pond.

2. Breeding of mandarin fish

L, the configuration of fish feed for mandarin fish species the allogenic silver crucian carp black carp is selected. The crucian carp hair pond is carried out according to the conventional method around April 10, and reaches the specification of about 20,000 fish per kilogram at the beginning of May, which is the palatable bait for mandarin fish.

2. Summer flowers of mandarin fish are released in May at a density of 2000 fish per mu; bait fish are mixed with mandarin fish in the same pond, that is, mandarin fish and bait fish are mixed according to the ratio of 1RV 200mi 300. This density can make mandarin fish get sufficient food, meet the feeding needs of mandarin fish and promote their growth. In order to meet the growth needs of bait fish, feed 1 kilogram of soybeans or soybean cake and 10 grams of water ground soybean milk or soybean cake milk once a day. After intensive cultivation for about one month, the survival rate of mandarin fish is more than 70%, and about 1500 large size mandarin fish with more than 5 cm per mu can be produced.

III. Commercial mandarin fish culture

1. After intensive cultivation of large size mandarin fish and bait fish for about one month, 70% of the pond water is pumped out, netted, fished and counted, kept at the density of 500 Mu 800 per mu, transferred to commercial mandarin culture, and the surplus mandarin fish species are sold. During the stocking of mandarin fish, the summer flowers of silver crucian carp were released at the density of 5000 per mu, and some wild miscellaneous fish with strong reproductive ability were properly released to reproduce many times to supplement the shortage of bait fish, so as to enhance the self-supply capacity of bait fish in mandarin fish culture ponds.

2. Feeding management the method of feeding mandarin fish at intervals in the development stage, feeding every 10-l5 days in the early and later stages, and every 10 days in the middle, about 50 kg per mu of water, to ensure that the ratio of mandarin fish to bait fish is 1:8, the feed fish is too thin, and mandarin fish will consume too much physical energy because of chasing bait fish, which is not conducive to mandarin fish fattening and fattening. If the density of food fish is too high, it will increase the total oxygen consumption, which is easy to cause anoxic floating head of mandarin fish, which is also not conducive to the growth of mandarin fish. In the process of culture, the total number of feed fish per mu is 1200 kg, the production of mandarin fish is 280kg, and the feed coefficient is about 4. After more than four months of feeding and management, by mid-October, most of the mandarin fish had reached 0.4 per cent, 0.45 kg. At this time, they could be caught in batches and caught in dry ponds by the middle of October. The commodity rate could reach more than 85%, and the survival rate was more than 95%.

Adult Shrimp Culture in Autumn

The main results are as follows: 1. 5-7 days before shrimp fry are released in dried mandarin fish pond. The pond inflow is 0.5ml 0.6 meters, and then base fertilizer is applied. Fermented livestock manure can be used to cultivate natural bait organisms as palatable shrimp fry bait. The general mu stocking specification is 2000,000 8-l0 kg per kilogram of prawn fry. At this time, the green shrimp has passed the peak period of breeding, and the number can be controlled.

2. Set up the net green shrimp like to live in the shallow water area and crawl in the pond side beach foot, in the pond culture process, only use the shallow water area of the pond slope beach foot, the water space in the middle of the pond can not be fully utilized. In order to overcome this shortcoming, net is set up in the pond to make full use of the pond space and water body, so as to improve the specification and culture yield of green shrimp. The area set by the net is about 20% of the total area of the pond. The net uses a thin-eye mesh with a width of 2 meters, which is 0.4 meters and 0.5 meters from the water surface when it is set up, slightly inclined to the foot of the pond bank and evenly spaced. The net setting was completed 3 days before the stocking of shrimp fry.

3. The reasonable feeding variety is mainly the special pellet feed for high-quality green shrimp, the particle size is fine in front and coarse after coarse, and the quality is excellent after fine. In the first half of the month, shrimp saplings were fed with full price crushed No. 1 feed 0.5ml kg per mu per day, and in the second half of the month, No. 2 feed was used for 1.5ml / mu per day, and then it was converted to No. 3 feed, supplemented by green bran, wheat bran, bean cake, surimi, silkworm pupa, crushed snails, etc., calculated according to the body weight of shrimp in the pond, generally 15% in the early stage, 8% in the middle stage, and 5% in the later stage. The actual dosage should be controlled within 4 hours after eating the shrimp 2mi. The feeding method is usually twice a day, 8: 00 to 9: 00 in the morning, accounting for 30% of the total daily feed, in the middle of the pond, and around 5: 00 in the afternoon, accounting for 70% of the whole day's feeding, which is invested around the pond and on the net. Feed to achieve "four look"-look at the season, weather, water quality, shrimp activity growth; "four fixed"-timing, positioning, quality, quantitative.

Fifth, water quality management, whether mandarin fish culture or shrimp culture, has higher requirements for dissolved oxygen in water, so attention must be paid to water quality control in the process of culture, and the core is to maintain a high level of dissolved oxygen all the time.

The main results are as follows: 1. The oxygen consumption rate of mandarin fish cultured mandarin fish is almost twice as high as that of domestic fish, and floating head phenomenon occurs when the dissolved oxygen content is lower than 5mg/L. Therefore, during the culture period, part of the pond water is changed every 5 days, so that the water depth is about 1.5 meters, and the transparency is kept between 35 and 45 centimeters, so as to facilitate the feeding of mandarin fish. Sultry and thunderstorm weather properly increase oxygen to ensure sufficient oxygen in the pond and avoid anoxic floating head of mandarin fish.

2. The water quality of shrimp culture ponds requires freshness, high oxygen content and no pollution. The early stage is mainly fertilizer and water, and the transparency is about 25 cm. In the middle and later stage, the water is frequently added or changed, the transparency is about 35 cm, and the water change is generally carried out in the afternoon on a sunny day. During the growth period, calcium superphosphate and quicklime are used alternately every 20 days, the dosage per mu: calcium superphosphate 3m 5kg, quicklime 10m m 15kg. Never mix the two or use them at the same time.

VI. Prevention and control of diseases and enemies

1. Mandarin fish culture

(l) the mixture of copper sulfate and ferrous sulfate (5:2) was applied every half a month within two months after the summer flower release of mandarin fish.

(2) A large number of parasites of ring worms occurred in mandarin fish around the middle of June, resulting in black body color, Gill edema, thin body and non-feeding, which can be prevented by crystal trichlorfon with a concentration of 0.1 × 10 ~ (- 6). Pay attention to temperature and weather conditions when sprinkling.

(3) Siniperca chuatsi can be prevented by spraying strong insecticidal Ⅰ with concentration of 0.25mg/L until the middle of September.

2. Black Gill disease and shelling failure occur in green shrimp culture, which can be sprinkled with 15kg quicklime per mu. The emergence of carp, crucian carp, Loach and other wild fish must be removed in time, generally per meter of water depth with "clear pond net" 0.5 kg, can kill all wild miscellaneous fish without affecting the survival of prawns. Moss appears in the pond, which endangers the survival of green shrimp and affects its quality. at present, the effective method is to use "efficient lichen removal agent", 45 grams per meter of water depth, sprinkle on the growth of moss, and all the moss disappear after three days, which is beneficial to the growth of green shrimp.

7. According to this model, the rotation culture of mandarin fish and green shrimp can produce 1500 large-scale mandarin fish per mu, with a survival rate of more than 70%. Half of them are kept until the middle of October, the yield of commercial mandarin fish per mu is 285kg, the survival rate is 95%, and the commodity rate is more than 85%. Green prawns were raised until early April of the following year, and the yield per mu was about 75 kg of commercial shrimp with a yield of 200 per kilogram of 250 shrimp.