Extended data
breeding technology
Pond culture techniques of adult crucian carp;
Carassius auratus is cultured in ponds, which mainly adopts four cultivation methods: mixed culture in ponds, interplanting in fingerlings ponds, interplanting in parent ponds and main culture in ponds.
1, polyculture in a fish pond. Mixed culture of crucian carp in adult fish ponds, mixed culture of herring, grass carp, silver carp, bighead carp, bighead carp, bighead carp and carp. Large fish should be stocked. let go
Feeding time should be sooner rather than later, that is, stocking in winter is better than stocking in spring. The stocking density is 150 ~ 250 animals per mu of water surface. The stocking specifications and quantity of other fish shall be determined as required. The requirements of crucian carp culture ponds are not high, and generally a pond with an area of 0. 1 ~ 2 hectares and a water depth of 1.5 meters is enough.
It is better to have 10 ~ 15 cm thick silt at the bottom of the pond. The survival rate can reach about 80% by cleaning, disinfecting and applying base fertilizer in the pond according to the conventional method. After about 200 days of cultivation, most individuals weigh more than 200 grams, and the yield per mu of water surface reaches more than 20 kilograms.
2. The pond is mainly cultivated. The area required for raising crucian carp in the pond is 0. 1 ~ 0.2 hectares, the water depth is more than 1.5 meters, and there is silt of 10 ~ 15 cm at the bottom of the pond. Ponds with domestic sewage in front of and behind the village are more suitable for raising crucian carp.
Clean the pond with quicklime one week before stocking fish, and inject water 2-3 days after disinfection. When injecting water, filter with a screen at the water inlet to prevent wild fish from entering the pond. 65,438+0,500 overwintering fish of Carassius auratus with 5.0-6.5 cm per mu of water surface or 2000 large fry hatched in the same year, and 40% (600-800) overwintering fish of grass, silver carp and bighead carp.
The stocking time should be sooner rather than later. Dietary concentrate supplemented by fertilization and aquaculture water quality. The annual feeding amount of concentrate is equivalent to about 2.5 times of the estimated yield of Pengze crucian carp. Fixed-point feeding is adopted, and the daily feeding amount depends on the growth of fish, weather, water temperature and feeding intensity of fish, and timely fertilization or fresh water is added according to the water quality.
Under the general management level, 200 kilograms of crucian carp can be obtained in that year, with an average weight of 1.50 grams per tail, and 200 kilograms of grass, silver carp and bighead carp can be obtained. Due to the high proportion of high-quality fish, its net profit is also higher than other aquaculture models.
3. Culturing crucian carp in fry pond. Fish can be raised in the fry ponds of grass carp, silver carp, bighead carp, bream and bream, but not in the fish ponds of carp and tilapia. The area of the pond should be 0. 1 ~ 0.2 hectares, and the water depth should be 1.0 ~ 1.5 meters.
The cleaning, disinfection and base fertilizer application of the pond are the same as the conventional methods. Carassius auratus is nested in other fry ponds, and only the fish hatched that year can be stocked. The stocking time should be sooner rather than later. Generally, when the fish hatched in the main breeding year is transferred to winter fish breeding, the crucian carp hatched in that year should be released immediately for breeding;
The stocking specifications should be large but not small, and the stocking density is 0.07 hectares of water 150 ~ 220. The stocking quantity, specifications and proportion of mating species of other fish species hatched in that year depend on the production needs and pond specifications. Carassius auratus fry is a bottom fish, which generally does not affect the living space of domestic fish species and can make full use of water space.
Therefore, the fish hatched in that year were interplanted in the fry pond, which basically did not affect the stocking density and the specifications of the main fish species. In addition, because crucian carp mainly eats residual bait and animals and plants at the bottom of the pond, there is basically no need to increase investment in funds and feed.
Under normal feeding and management conditions, crucian carp fry are interplanted in the fry pond. After 150 ~ 180 days of feeding, the water standard can reach more than 200 grams at the end of the year, and the adult fish can gain 25 ~ 40 kilograms per 0.07 hectare of water surface.
4. Culturing crucian carp in parent fish culture pond. In southern China, the artificial reproduction of domestic fish can generally end in the middle and late May. The gonad of postpartum parent fish is in recovery period. In order to restore the physical strength of parent fish as soon as possible and promote gonadal development, ponds are mostly intensively managed.
In this fish pond, in addition to arranging parent fish breeding and other fish collocation, 200 crucian carp of 5-6 cm can be put into every 0.07 hectare of water surface. Carassius auratus is nested in the parent fish breeding pond, and the stocking time is generally carried out at the same time as the parent fish, and the breeding (breeding) method is carried out according to the conventional method of raising the parent fish.
The breeding of parent fish should follow the law of gonad development. Generally, the crucian carp in the parent fish culture pond can't be caught in the dry pond at the end of the year, and it can only be completely caught when the parent fish is intensively cultivated before delivery in the next year. After 250 ~ 300 days of feeding, 25 ~ 45 kilograms of crucian carp can be obtained per 0.07 hectare of water surface, with an average weight of more than 200 grams.
Small carp head is black and fat (a few are white), abdomen is big, spine is raised, body length is 15 ~ 20cm, which is streamlined (also called spindle), body height is flat, front part is curved, back contour is raised, and tail handle is wide. The abdomen is round and has no muscle. The head is short, the kiss is dull and unnecessary, the gill rake is long and the gill silk is slender. Hypopharyngeal teeth are flat, with large scales and slightly curved lateral lines.
The dorsal fin is long and the outer edge is flat. Gill rakes are slender, needle-shaped and closely arranged, and the number is 100 ~ 200. The dorsal fin and the gluteal fin have strong third spines and serrated trailing edges. The end of pectoral fin can reach the beginning of ventral fin. The caudal fin is deeply forked, the back is silvery gray with a slight yellow luster, the abdomen is silvery white with a slight yellow color, and each fin is grayish white.
The big one can weigh one or two Jin. Living in soft mud can nourish the stomach. In March and April, crucian carp is thick, with many eggs and delicious taste. Crucian carp is the top grade of fish, living in freshwater waters such as ponds, lakes and rivers. According to the different growing waters, the body color is also different.
The abdomen is light white and the back is dark gray. Natural enemies look down from the top of the water, because the black fish back is the same color as the mud at the bottom of the river, it is difficult to be found; If the natural enemies look up from under the water, it is difficult to find because the white fish belly is almost the same color as the sky; I often see in some articles that "the eastern sky is a fish-belly grey" in the early morning, which is the reason. It belongs to protective color.
Living habits
Crucian carp (Carassius auratus) is an omnivorous fish that lives in fresh water, with a plump body and graceful swimming posture. The living standard of crucian carp belongs to the bottom fish. Generally speaking, they swim, feed and inhabit underwater. When the temperature and water temperature are high, they will also swim in the lower and upper layers of the water for food.
Adult crucian carp is mainly plant food. Because plant feed is rich in water, there are many edible varieties and a wide range. The stems, leaves, buds and fruits of vascular weeds are the favorite foods of crucian carp.
In the waters where higher aquatic plants such as water chestnut and lotus root grow, crucian carp can get all kinds of rich nutrition best. Diatoms and some algae are also the food of crucian carp, as well as shrimp, earthworms, young snails, insects and so on.
Carassius auratus is fattest in February-April and August-65438+February. Except the western plateau, it is widely distributed all over the country. Crucian carp has strong adaptability, and can survive in deep or shallow water, running water or still water, high temperature water (32℃) or low temperature water (0℃). Even in strongly alkaline waters with pH:9 of 9, Dali Lake with salinity as high as 4.5% can still grow and reproduce.
The feeding time of crucian carp varies with seasons. Spring is the peak season for feeding, feeding day and night; The feeding time in summer is morning, evening and evening; Feeding all day in autumn; In winter, they eat at about noon.
Crucian carp like to walk in groups. Sometimes with the water, sometimes against the water, they feed and lay eggs in shoals, bends, ditches and reeds rich in aquatic plants; When the current is slow or static and the bait is sufficient, they will temporarily settle down. ?
Crucian carp living in lakes and large reservoirs
It is also a choice of food. Especially shallow water aquatic plants, are the places where they are concentrated. Even in winter, they like grass roots, and most of them don't swim in the deep water without grass for the winter.
Carassius auratus living in rivers and ponds
They drift with the tide, stop when there is no flow, choose food and live in the depths of the water in winter.
Cleaning of crucian carp
In order to sell crucian carp well and keep it for a long time, hotels and food markets like to keep it fresh. Some unscrupulous traders use chemical products to keep the crucian carp in good condition and pursue good sales: formaldehyde can bring the deteriorated crucian carp back to life, and sodium benzoate can make the crucian carp "stay young forever", so eating crucian carp should remove these harmful substances.
Method: Put all the crucian carp into the basin, and then add a little residual detergent into the water. Part of the water covered by residual detergent is isolated from the air. When the crucian carp is in the water, it will feel anoxic and will stretch out its body to breathe, thus achieving a clean effect.
If you want to clean it again, change the water several times and add residue to clean it. Note: clean up the residue properly, and don't add too much, otherwise the crucian carp can't breathe in the water and is easy to suffocate and die.
Experts say that when we eat crucian carp in our daily life, it is best not to go to street stalls to eat it, but to eat it at home. We must pay attention to the hygiene and cleanliness of crucian carp.
References:
Crucian carp Baidu baike