What Is the Most Suitable Stocking Density and Water Depth for Grass Carp Farming?
Grass carp is one of the common fish on our dining tables. Grass carp is not only tender and delicious, but also has extremely high nutritional value, containing rich DHA, calcium, iron and other elements. Eating it often is of great help to health. Grass carp can be farmed artificially and grows quickly, so do you know what the density and water depth requirements are for farming grass carp?
What Stocking Density Is Best for Grass Carp Farming
If grass carp are to be grown to a size of 2-3 jin/fish, generally 800-1500 grass carp fry of 0.1-0.3 jin/fish are stocked at the beginning of the year per mu, and additionally three sizes of fry - 0.1-0.3 jin/fish, 0.3-0.7 jin/fish and 0.7-1.0 jin/fish - are stocked at 300-500 fish/mu each.
For grass carp farmed to 5 jin/fish for market, generally 300 grass carp of 2-3 jin/fish are stocked per mu, 40 bighead carp of 1.8-2 jin/fish per mu, 500 crucian carp of 0.2 jin/fish per mu, and 1000 mud carp of 0.1 jin/fish per mu.
What Water Depth Is Best for Raising Grass Carp
The pond area for raising grass carp should preferably be 10-20 mu, the water depth 2-2.5 m, and the silt thickness no more than 20 cm. For every 10 mu of pond, one 3 kW aerator and one automatic feeder should be provided.
Pond Conditions for Grass Carp
1. Pond conditions: The pond is required to be far from pollution sources, with an area of 5-10 mu, a flat bottom, and a bottom soil preferably loam, with slight seepage being ideal, bottom mud of 10-20 cm, and a water depth of about 2 m. Each pond should be equipped with one 3 kW impeller-type aerator and one 4-inch water pump to allow timely water changing and aeration.
2. Clearing and disinfection: Grass carp itself has many diseases, and ponds are even more prone to outbreaks of epidemics. At the same time, eliminating trash fish is an important measure to ensure normal feeding of grass carp and save feed. The specific method is, when the pond is dry (with 5-10 cm of water remaining), to spread 100 kg of quicklime per mu after slaking it into slurry over the whole pond, or to spread 10 kg of bleaching powder per mu dissolved in warm water over the whole pond, leaving no dead corners or untreated surfaces, so as to thoroughly kill pathogenic bacteria.
3. Water quality requirements: The pond water quality requires a pH value of 7.5-8.5. During the peak farming period (June to September), the pond water transparency should be kept at about 30 cm, and the organic matter oxygen consumption should be 18-20 mg/L.
Feeding and Management of Grass Carp
1. Feed feeding: Mainly feed pelleted feed with a protein content of 28-32%, supplemented with green fodder. Feed feeding follows the principles of “coarse first, fine later” and “four fixed and four observe”. Generally, feed twice a day, and it is advisable that the feed be finished within 2 hours and that the grass carp eat until 80% full. After continuously feeding pelleted feed for a period, pelleted feed should be stopped for 1 week, and during the interval, raw grain feed should be given. Usually, pay attention to appropriately adding vitamins and other drugs to the feed to avoid diseases such as hepatobiliary syndrome in grass carp that may cause massive death.
2. Water quality management: Use the aerator correctly. From June to October, on sunny and windless days, turn on the machine for aeration for 2 hours every day from 1 to 3 p.m., and aerate at appropriate times in the early morning. On consecutive cloudy days, aeration should be started earlier. Add fresh water to the pond at appropriate times, and adopt the method of “small discharge and small intake, multiple water changes” to gradually regulate water quality. From June to September, add fresh water once every 3-5 days, about 10 cm each time, and every 15-20 days, use 10-20 kg of quicklime per mu of water surface at 1 m depth, slaked into slurry, and spread it over the whole pond once.
3. Disease control: Feed using the method of “coarse first, fine later, combining fine feed and green fodder” to control the occurrence of hepatobiliary syndrome in grass carp. Common diseases of grass carp include red skin disease, gill rot disease and enteritis disease. Generally, a combination of oral administration and external splashing is adopted for treatment. External splashing mainly uses disinfectants such as bleaching powder and chlorine dioxide, for 3 consecutive days. For oral administration, “Sanhuang powder” medicated bait has a relatively good effect. For every 50 kg of fish body weight, use 0.3 kg of Sanhuang powder (50% rhubarb, 30% phellodendron, 20% scutellaria, ground into powder and mixed evenly), mix it evenly with flour paste, then mix it into the feed for feeding, for 3-5 consecutive days.
4. Timely harvesting: Timely catching large-sized adult fish for market is an important measure for high-yield grass carp farming. The main purpose is to reduce the fish-carrying capacity of the pond water body and promote the rapid growth of the pond fish in the later stage. Generally, one harvest is carried out at the end of July, catching fish in the early morning when the water temperature is lower.
Through the above content, I believe everyone has gained a certain understanding of the requirements for farming grass carp. Although farming grass carp has certain prospects and economic benefits, you must also pay attention to the techniques and precautions for farming grass carp.