What are the key points to note in bighead carp and silver carp farming?

Large lake and reservoir bighead carp-dominant polyculture model

Stock once, harvest twice. Bighead carp fingerlings of about 0.3 jin to 0.6 jin per fish are stocked at about 70 fish per mu, and those of about 1.2 jin to 1.5 jin at about 50 fish per mu. Harvesting of the large ones begins in July to August, and the rest are harvested from October to December. Silver carp are stocked at 20 to 30 fish per mu, along with a certain quantity of bottom-dwelling crucian carp and common carp. Time for stocking fingerlings: before the Spring Festival.

Stock once, harvest at year end. The stocking rate for bighead carp fingerlings is about 120 to 150 fish per mu for fingerlings of 0.3 jin to 0.6 jin per fish, raised until harvested at year end. Silver carp are stocked at 20 to 30 fish per mu, along with a certain quantity of bottom-dwelling crucian carp and common carp.

Medium-sized intensive culture water bodies with bighead carp as the main species (intensive culture water bodies of 100 mu to 1000 mu)

The ratio of silver carp and bighead carp to food-eating fish is 1:1. On the one hand, this makes full use of water body resources and raises yield and benefits; on the other hand, it can control cyanobacterial blooms. Bighead carp fingerlings of about 0.5 jin per fish, about 1 jin per fish, and about 1.5 jin per fish, and silver carp fingerlings of about 0.3 jin to 0.5 jin per fish, are each stocked at about 40 fish. Harvesting of the large ones while keeping the small ones begins in July. Stock a certain quantity of bottom-dwelling crucian carp and common carp. Feed for the food-eating fish is given by ordinary methods. (Intensive fish ponds may follow this method.)

With bighead carp as the main farmed species. Bighead carp fingerlings of 0.3 jin to 0.5 jin per fish, about 1 jin per fish, and about 1.5 jin per fish are each stocked at about 50 fish, silver carp of about 0.3 jin per fish are stocked at about 30 fish, and a certain quantity of bottom-dwelling crucian carp and common carp is also stocked. Starting in July, keep an eye on market conditions and harvest the large ones while keeping the small ones. Total output is above 500 kg per mu.

Choice of fishery fertilizer

Choose modern biological organic compound fertilizer. Besides containing large amounts of major elements such as nitrogen, phosphorus and carbon, it also contains balanced trace elements, multiple amino acids, multiple organic matters, peptides, beneficial bacteria, fertilizer efficiency enhancers and so on. It is not only rich and comprehensive in nutrients, but can also fertilize the water, improve the water and control the water, providing a good living environment for fish. It is especially suitable for culturing large algae, rotifers, cladocerans, copepods and other plankton that bighead carp like to eat, providing a guarantee for high-yield bighead carp farming.

Fertilizer application methods: base fertilizer is normally applied in sufficient amounts. In March, apply fermented manure once at 300 kg per mu, and apply an amino acid water-fertilizing paste once. Starting in April, apply amino acid biological organic fertilizer at about 4 kg per mu for 1 m water depth. Apply fertilizer once every 5 to 7 days on sunny mornings. In mid-June, apply manure once at 300 kg per mu. In July, August and September, apply appropriate phosphorus and nitrogen fertilizer. In November, apply a bodyguard fertilizer once. Fertilizer is used about 30 times throughout the year. The effect of fertilization is judged by maintaining water transparency at about 30 cm.

At present, the main types of fish fertilizer include compound fertilizer, mixed fertilizer, compound mixed fertilizer, organic mixed fertilizer and biological organic fertilizer. Some organic mixed fertilizers are made by adding organic matter (such as chicken manure) to inorganic mixed fertilizer. True biological organic fertilizer is made by inoculating high-energy organic matter with specific microbial communities, fermenting and decomposing it under specific artificial conditions, and then adding some beneficial bacteria, fertilizer efficiency enhancers, specific enzyme preparations, trace elements and so on. Some manufacturers pass off organic mixed fertilizer as high-efficiency biological organic fertilizer, which cannot achieve the high-yield goal for bighead carp farming.

Water quality control issues

Bighead carp-dominant farming requires fertilized water containing more than 30 mg of biomass per liter of water. The use of amino acid biological organic fertilizer, with its rich composition and diverse functions, is helpful. If the water is not fertile enough, bighead carp will not have enough food and their growth rate will slow down. If the water is too fertile, Microcystis will appear, deteriorating the water body environment; the growth rate of bighead carp will also slow down, and quality will decline and off-flavors will appear. Fertilization must therefore be scientific.

Disease prevention and control

After disinfecting and killing insects in the pond bottom and water body, release the fry. Around March to April, carry out one fish microscopic examination; if parasites are present, use insecticide to kill the parasites. The first insect-killing treatment should be completed before April 30, with a dosage of about 200 L of technical material; the second depends on the specific situation. The first disinfection, combined with the insecticide, should be completed before April 30, using chlorine dioxide or dibromohydantoin technical powder at a dosage of about 1500 kg. Prevention of hemorrhagic disease: based on the disease patterns of past years, use it 1 to 2 times. The first time should be completed before July 1, with a dosage of 200 L of technical material; the second time is around August 10, depending on the specific situation.