CATDOLL : CATDOLL: If you want to make more money from fish farming, what are the technologies to increase the production and efficiency of silver carp?

If you want to make more money from fish farming, what are the technologies to increase the production and efficiency of silver carp?

1. Food Supply

Both silver carp and bighead carp are filter-feeding fish that mainly feed on plankton, organic debris and bioflocs. They can also be fed artificial feeds. The difference is that silver carp mainly feeds on zooplankton, while bighead carp mainly feeds on phytoplankton.

We can improve the food supply of silver carp from the following four aspects.

1. Directly supplement food: feeding feed, such as using fermented feed and silver carp special feed to directly increase food supply.

2. Fertilize water: Add organic fertilizer, inorganic fertilizer, biological fertilizer, etc. to promote the growth of plankton. You can use Hechenhua silver carp special biological fertilizer: water nanny + silicon calcium quick supplement to promote the growth of biological bait and balance the algae phase.

3. Supplement beneficial bacteria: Use beneficial bacteria to decompose organic matter in the pond and form bioflocs. You can use Hechen Water Enzyme, concentrated photosynthetic element, and biological water purifier.

4. Bottom improvement: Oxidize and decompose the pond bottom and reuse the nutrients on the bottom of the pond, such as using quicklime, potassium persulfate, etc. to oxidize the bottom. You can also use Hechen Biological Bottom Cleaner for biological bottom improvement.

When stocking the fish, it is also necessary to consider the food competition between silver carp and other organisms in the pond: for example, crucian carp also mainly feed on zooplankton, algae, organic debris, etc. If there are too many crucian carp, the amount of silver carp stocked can be appropriately reduced; snails will also compete with silver carp for food, so if there are too many snails, a small amount of black carp can be added to inhibit the growth of snails.

2. Grading feeding

Graded breeding can rationally utilize the pond's breeding space and food, so it is recommended to match fish species of different sizes: mainly silver carp, which can be raised in three sizes of 0.2 to 0.3 jin, 0.5 to 0.8 jin, and 1 to 1.5 jin; the size of bighead carp is 0.2 to 0.5 jin.

The advantages of this method are: ① It reduces the competition for food between big silver carp and bighead carp; ② After the big silver carp are released, only small-sized silver carp need to be supplemented, which is conducive to rotation of catch and release and reduces the cost of stocking.

3. Reasonable close breeding

Reasonable density breeding takes into account the limited carrying capacity of the pond. Too high density may lead to slow growth of fish, more diseases, and failure to reach the market specifications as scheduled; too low density will increase the cost of fish per kilogram and reduce the breeding efficiency.

Since the economic value of silver carp is much higher than that of bighead carp, in the efficient breeding model of silver carp, the main goal should be to increase the output of silver carp, so it is recommended to increase the proportion of silver carp. As shown in Figure 3, for the same 200 silver carp, the higher the proportion of silver carp, the higher the benefit per mu.

It is best to choose free-range breeding, control the water quality, and catch the fish in time, and try not to release too many.

You must clean the fish pond regularly, and you also need to know how to use high-quality fertilizers to avoid disease.

I personally think that we can think systematically from the following five aspects: ① Food supply; ② Grading and breeding; ③ Reasonable intensive breeding; ④ Rotational catching and releasing; ⑤ Breeding management. Add organic fertilizer, inorganic fertilizer, biological fertilizer, etc. to promote the growth of plankton. You can use the special biological fertilizer for silver carp: water nanny + silicon calcium fast supplement, promote the growth of biological bait, and balance the algae phase. Grading and breeding can make reasonable use of the breeding space and food in the pond, so it is recommended to match fish of different sizes.

Are there any good techniques for breeding catfish?

Key points of catfish farming technology

Source: China Animal Husbandry Street

Catfish (Silurus asotus) belongs to the order Siluriformes, family Siluridae, genus Silurus. Heilongjiang catfish is not only large in size and fast in growth, but also resistant to low temperatures and hypoxia, and has delicious meat, making it popular among producers and consumers in the northern high-altitude cold regions. Based on many years of practice, the author summarizes the catfish pond farming technology as follows.

1. Artificial breeding of catfish in ponds

Selection of broodstock: Choose fish with tail weight of more than 0.5kg. Female fish with enlarged abdomen, red and swollen genital opening, and eggs can be squeezed out by light pressure on the abdomen. Male fish with narrow abdomen can squeeze out white semen by light pressure on the abdomen. The male-female ratio is 1:1-1.5, and the individual size is appropriate.

Aphrodisiac: Catfish breeding practice has shown that after prenatal cultivation of catfish gonads to the end of stage IV, the best induced labor drug to use is a mixture of dioconazole maleate (DOM) and luteinizing hormone releasing hormone A2 (LHRH-A2). The dosage is 2mg~5mgDOM+2μg~4μgLHRH-A2 per kilogram of catfish. The mixture of the two drugs is injected once into the back muscle, and the induced labor rate can reach more than 80%.

Artificial nest: catfish spawning attachments are arranged in the spawning pond, the method is similar to that of carp, but catfish eggs are not as sticky as carp eggs, and some eggs are easy to fall off the fish nest and fall to the bottom of the pond and die. In order to improve the utilization rate of catfish eggs, a bottom nest should be arranged at the bottom of the spawning ovary. The method is to weld iron rods with a diameter of 0.8 to 1 cm into a 3m×1m rectangular frame, connected in the middle with screen silk, and palm skin with eggs sewn on the screen silk. The bottom nest egg rate accounts for 20-40% of the total number of eggs laid.

Artificial hatching: After the catfish lays eggs, the ovaries should be taken out and put into the hatching pond in time to prevent the parent fish from mutilating their eggs. The hatching pond is preferably a cement pond. The bottom of the earthen pond should be flat and free of silt. The water depth should be within 0.5-1m. The area should not be too large. The density of eggs is 30,000/m2 of water surface. The water quality needs to be strictly filtered to prevent the harm of aquatic animals to fish eggs. The other hatching processes are similar to those of carp. When the water temperature is around 20℃, the membrane will break and the fry will emerge in 3-4 days. The newly emerged catfish fry will be attached to the fish nest and develop under still water or micro-flowing water conditions. They are tadpole-shaped. The fish nest should be taken out in time 3 days after hatching and put into the pond in time.

2. Pond culture technology

Catfish fry ponding: Catfish can actively eat large rotifers and small cladocerans 3 to 4 days after hatching, so they should be put into the pond in time. The abundance of cladocerans after catfish fry are the key to the survival rate of catfish fry. Cladocerans are cultivated in large quantities by applying organic fertilizer. When natural bait is insufficient in the later stage, cladocerans or fresh animal bait can be scooped from other ponds with a 50-mesh screen or cut into pieces and fed. There is enough animal bait in the pond, and the catfish fry grows faster. Generally, about 90,000 catfish are put in 667m2. After 10 to 15 days, they will grow into summer flowers, and the survival rate can reach 50%. The water surface of the pond for planting is preferably within 667m2.

Fish breeding:

Ecological breeding and cultivation of catfish species: a large amount of organic fertilizer is applied to cultivate zooplankton, benthic organisms, aquatic insects and small fish, providing catfish with nutritious animal live bait. This method has a high survival rate and large size. In 1997, 2,500 summer catfish were stocked in a 4,000m2 pond, accounting for 54.3% of the total stocking, 700 summer silver carp, accounting for 15.3% of the total stocking, and 1,400 summer silver carp, accounting for 30.4% of the total stocking. 200 crucian carp broodstock were stocked 17 days before the stocking of catfish fry to allow them to reproduce naturally. 500kg of basal fertilizer and topdressing were applied per 667m2, and 150kg of powdered feed was fed to feed crucian carp fry. After 90 days of feeding, the catfish produced an average of 50.5kg per 667m2, with a survival rate of 94.8% and a size of 128g/tail. The survival rate of silver carp is 78%, and that of bighead carp is 85%. This breeding method is simple and easy to master, and crucian carp fry are easy to obtain as bait fish. The stocking density of catfish fry should be determined by the amount of bait fish, and catfish fry can only be stocked 10 days after silver carp is stocked.

Fish pond with catfish summer flower: Adding less than 10% of catfish summer flower to fish pond can not only remove wild fish, aquatic insects, tadpoles, etc. in the pond, but also increase the yield of the main cultured fish species and improve the efficiency of the pond. In 1995, 12.2% (500 fish/667m2) of catfish summer flower were stocked in the domesticated main carp pond. In 1996, 6.67% (300 fish/667m2) of catfish summer flower were stocked. Without affecting the survival rate and yield of the main fish, the catfish yield per 667m2 increased by 43.75kg (feeding part of the chicken intestines) and 16.2kg.

Raising catfish fingerlings in adult fish ponds: This method requires low investment, has high benefits, and does not require additional management measures. In particular, in adult fish ponds with a large number of small miscellaneous fish, 100 to 200 summer catfish can be stocked per 667m2, which can breed 10 to 20kg of catfish fingerlings weighing 100 to 150g each, increasing benefits by 200 to 200 yuan per 667m2.

Catfish breeds are domesticated and cultivated with pellet feed: Catfish grow faster and have a higher survival rate when fed with natural animal feed or terrestrial animal feed. They also eat artificial pellet feed when hungry, and can be domesticated and cultivated in ponds with pellet feed. However, the nutritional requirements for feed are relatively high. The protein content of pellet feed in domestication and cultivation is higher than that of carp. The protein content of catfish feed should be about 40%, and animal protein (imported fish meal) should account for more than 30% of the feed protein. The processing and domestication methods of pellet feed are basically similar to those of carp. The tail weight of catfish bred by this method can reach 50-100g. In 1997, 6,000 catfish were raised in a pond of 667m2 and domesticated with pellet feed. 667m2 produced 93.5kg, the feed coefficient was 3, the average tail weight was 84.5g, and the survival rate was 18.44%. The author believes that the main reason for the low survival rate of catfish is that the bait is not palatable and the nutrition is incomplete, resulting in uneven sizes. Large individuals swallow small individuals. When the catfish weigh about 10g, they kill each other seriously, which is the main factor affecting the large-scale production of catfish. In order to improve the survival rate of catfish, some palatable animal bait should be supplemented from the beginning of summer.

Fish farming:

Catfish are raised in the same year as commercial fish: Catfish are raised in the same year as commercial fish in the ponds rich in small fish. About 30 catfish are raised in 667m2. The annual weight can reach more than 0.35kg, and the largest individual can reach 0.75kg. 667m2 can increase catfish production by 5-10kg. When raising catfish, the density should be flexibly controlled according to the water source conditions and the number of fish in the pond.

The fish pond is matched with catfish spring fillet fish: catfish swim slowly and generally cannot prey on the fast-swimming farmed fish of the same size. Stocking catfish of a certain size in the pond can only remove small wild fish and sick farmed fish in the pond. The commercial fish pond is 667m2 and the tail weight is 50 to 100.