Introduction to pond culture techniques of individual large-growing fast catfish

Catfish culture

Catfish (Silurus asotus) belongs to the order Clariformes, Catfish family, catfish genus. Heilongjiang catfish is not only large and fast growing, but also resistant to low temperature, hypoxia and delicious meat, so it is deeply loved by producers and consumers in northern alpine areas. On the basis of years of practice, the author summarizes the techniques of catfish pond culture as follows.

1 artificial propagation of catfish cultured in ponds

1.1 selection of parent fish: the tail weight is above 0.5kg, the abdomen of the female fish is enlarged, the reproductive pore is red and swollen, and the eggs can be extruded by gently pressing the abdomen. Male fish have a narrow abdomen and can squeeze out white semen by gently pressing the abdomen. The ratio of female to male is 1 ∶ 1 to 1.5, and the individual size is suitable.

The reproductive practice of catfish proved that the reproductive glands of catfish reached the end of Ⅳ stage after prenatal cultivation. The best drug for inducing labor was a mixture of dione maleate (DOM) and luteinizing hormone releasing hormone A2 (LHRH-A2). The dose was 2mg ·5mg DOM + 2 μ g ~ 4 μ g LHRH-A2 per kilogram of catfish, and the mixture of the two drugs was injected into the back muscle of the two drugs at one time.

1.3 artificial nesting: arrange catfish spawning attachments in the spawning pond, the method is similar to that of carp, but the stickiness of catfish eggs is not as big as that of carp eggs, and some eggs are easy to fall off from the nests and die when they fall to the bottom of the pond. In order to improve the utilization rate of catfish eggs, bottom nests should be arranged at the bottom of the spawning nest. the method uses iron rods with a diameter of 0.8~1cm to weld into a rectangular frame of 3m × 1m, and the middle is connected with sieve silk, which is sewn with palm skin with eggs, and the rate of laying eggs in the bottom nest accounts for 2040% of the total number of eggs.

1.4 artificial hatching: after spawning, catfish should take out their ovaries and put them into the hatching pool in time to prevent parent fish from harming their eggs. The hatching pond had better be a cement pond, the bottom of the soil pond should be flat, there should be no silt, the water depth should be less than 0.5m 1m, the area should not be too large, and the density of eggs should be 30,000 eggs / m2 water surface. The water quality should be strictly filtered to prevent the harm of aquatic animals to fish eggs, and other hatching processes are similar to those of carp. The water temperature is about 20 ℃ for 3-4 days, and the newly emerging catfry adsorbs on the fish nest and develops in the condition of still water or micro-running water, shaped like a tadpole. After hatching for 3 days, the fish nest should be taken out and go into the pond at the right time.

2 Culture techniques in ponds

2.1 Catfish seedling hair pond: catfish can actively swallow large rotifers and small cladocera after 3-4 days of emergence, and then go to the pond in time. The abundance and deficiency of Cladocera after the catfish seedlings went into the pond was the key to the survival rate of catfish seedlings. When the natural bait is insufficient in the later stage, use a 50-mesh sieve net to get Cladocera or fresh animal bait from other ponds, cut up and feed. The animal bait in the pond is sufficient, and the growth rate of catfish seedlings is fast. Generally, the 667m2 is about 90, 000 tails, and the summer flowers are bred after 10 to 15 days. The survival rate can reach 50%, and the water surface of the hair pond had better be within 667m2.

2.2 Fish fingerling cultivation

2.2.1 Ecological cultivation of catfish species: a large amount of organic fertilizer is applied to cultivate zooplankton, benthos, aquatic insects and small miscellaneous fish to provide nutritious animal bait for catfish. This method has high survival rate and large specification. In 1997, 2500 catfish summer flowers were released in 4000m2 ponds, accounting for 54.3% of the total, silver carp summer flowers, accounting for 15.3% of the total, and 1400 silver carp summer flowers, accounting for 30.4% of the total. Two hundred crucian carp were released 17 days before stocking to make them reproduce naturally, applying base fertilizer and topdressing each 500kg per 667m2, and feeding powder feed 150kg to feed crucian carp fry. After 90 days of feeding, catfish produced an average of 50.5kg per 667m2, with a survival rate of 94.8% and a specification of 128g/ tail. The survival rate of silver carp is 78%, and the survival rate of flower silver carp is 85%. This cultivation method is simple and easy to master, and crucian carp fry as bait fish is easy to obtain. The stocking density of catfish fry should be determined by the number of bait fish, and the stocking time must be 10 days after silver carp stocking.

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

2.2.3 capturing catfish species in adult fish ponds: this method has the advantages of low investment, high benefit and no need to add other management measures, especially in adult ponds with more small miscellaneous fish, with 200 catfish per 667m2, it can be bred into 100kg 150g catfish fingerling 10~20kg, which can increase the benefit by 200,200 yuan per 667m2.

2.2.4 domestication and cultivation of catfish species with pellet diet: catfish fed on natural or terrestrial animal food grew faster and had a higher survival rate. Artificial pellet bait is also eaten in the state of hunger, and it can be domesticated and cultured in the pond. However, the nutritional requirements of bait are relatively high, the protein content of grain feed in domestication and culture is higher than that of carp, the protein content of catfish should be about 40%, and animal protein (imported fish meal) should account for more than 30% of feed protein. The processing and domestication methods of pellet feed are basically similar to those of common carp, and the tail weight of catfish bred by this method can reach 50 million 100g. In 1997, 6000 catfish were raised in 667m2's pond and domesticated with pellet bait. 667m2 produced 93.5kg with a feed coefficient of 3, with an average tail weight of 84.5 g and a survival rate of 18.44%. The author thinks that the main reason for the low survival rate of catfish is that the food is not palatable and the nutrition is not complete, which leads to uneven size, large individuals devour small individuals, and when the body weight of catfish reaches 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 fingerling, some palatable animal baits should be supplemented from summer flowers.

2.3 Adult fish culture

2.3.1 Summer flowers cultivated commercial fish in that year: catfish were released in adult ponds where small miscellaneous fish were abundant, and about 30 catfish were raised in 667m2. It can reach more than 0.35kg in that year, and the largest individual can reach 0.75kg. 667m2 increased catfish production by 5~10kg. When interbreeding, the density should be controlled flexibly by the water source condition and the number of miscellaneous fish in the pond.

2.3.2 Adult fish pond with catfish spring fillet species: catfish swim slowly, it is generally impossible to prey on farmed fish with fast swimming speed of the same specification, and catfish of certain specifications can only remove small wild miscellaneous fish and sick farmed fish in the pond. The tail weight of commercial fish pond 667m2 is 50 to 100.