Want to get rich raising shrimp? The key is to grasp five major factors

The farming model for whiteleg shrimp (Litopenaeus vannamei) is still the traditional farming model. With further development of farming, its drawbacks have become increasingly apparent. The traditional farming model can no longer substantially increase yield per unit area, and the comparative benefit of farming has declined; the quality of aquatic products has decreased, and the farming environment has deteriorated; the occurrence of diseases is becoming more and more serious, and most of them are explosive epidemics. Carrying out healthy farming is imperative, and it should start from the following aspects.

1. Stock high-quality seedlings

Vertical infection of whiteleg shrimp diseases is an important route of disease transmission. Cutting off the vertical infection route and stocking healthy, virus-free shrimp seedlings is the fundamental guarantee for healthy farming. Therefore, researching and cultivating healthy specific-pathogen-free seedlings is key. At present, Shenzhen has taken the lead in China in breeding specific-pathogen-free, highly healthy whiteleg shrimp seedlings (also known as SPF whiteleg shrimp seedlings) for the first time in China, but the price is relatively expensive, and some farmers still find it hard to accept for the time being.

2. Reasonable stocking density

At present, in the process of whiteleg shrimp farming, the phenomenon of high-density stocking is widespread. There is also a widespread mistaken belief among farmers: that high-density stocking can increase yield, and even if some seedlings die from disease, a certain density can still be maintained. Little do they know that many diseases are caused by excessive density. In addition, there is the issue of reasonably matching other farmed species, because reasonable matching can not only make full use of farming space and improve the farming benefit per unit of water body, but also play an important role in improving the aquatic farming environment, maintaining the microecology and ecological balance of the water body, inhibiting the growth of harmful microorganisms, and maintaining the dominant position of beneficial organisms, thereby effectively preventing the occurrence of diseases.

3. Scientific water management

Scientific water management first requires protecting the internal ecological environment of the shrimp pond, and fully grasping the water volume at each stage of the shrimp pond, the amount of feed fed and the amount of residual feed, the content of organic matter, and the content of toxic and harmful substances such as sulfides and ammonia nitrogen and other physicochemical factors. These are all directly related to the survival rate and growth speed of the shrimp seedlings.

Cultivating the farming pond water well is another important part of scientific water management. This is achieved through reasonable water exchange and drainage, cultivating other organisms in the water body (including zooplankton, phytoplankton, aquatic plants, beneficial microorganisms, other farmed species, etc.), as well as through fertilisation, spraying microecological preparations, or the reasonable use of certain chemicals.

Another aspect of scientific water management is to adopt measures such as sedimentation, filtration, and biological purification in drainage channels to effectively remove the content of harmful substances in the wastewater discharged from shrimp ponds, and to avoid and reduce new pollution generated by shrimp ponds.

4. Scientific feeding

(1) Pay attention to the quality of the feed. It is required to use complete compound feed instead of fresh live bait. Compound feed is required to be nutritionally complete, low in cost, low in feed conversion ratio, convenient to use, good in attractability, and not pollute the water quality.

(2) Pay attention to the location of feed feeding. In addition to fixing the feeding location, attention should also be paid to setting an appropriate number of feeding points, neither too many nor too few, to avoid feed waste and water pollution. Residual feed at feeding points should be removed in a timely manner, and feeding points should be disinfected regularly.

(3) Determine reasonable feeding times and frequency. Whiteleg shrimp have the habit of being active at night and resting by day, so feeding should take this habit into account and appropriately feed more in the evening. Generally speaking, the method of feeding small amounts multiple times is worth recommending. During seasons when diseases break out, the number of feedings can be appropriately reduced.

(4) Determine a reasonable feeding amount. The feeding amount should be determined according to different shrimp body sizes, different farming seasons, different climates, different environmental conditions, and farming conditions, rather than being fixed and unchanging. Under normal circumstances, it is advisable not to affect feeding at the next meal. Be careful not to let whiteleg shrimp eat too much, nor to let insufficient food intake affect their growth. During seasons when diseases break out, the feeding amount should be appropriately reduced, generally to about 80% of the usual amount.

5. Rational drug use

The purpose of rational drug use is to improve the prevention and control effect of whiteleg shrimp diseases and the quality of whiteleg shrimp. Rational drug use means starting from factors such as drugs, pathogens, the environment, the aquatic animals themselves, and human health, and using drugs purposefully, systematically, and effectively to achieve the effect of preventing and treating diseases. The positive and negative effects of drugs should be clearly recognised: on the one hand, drugs have the effect of preventing and treating diseases or improving the environment and enhancing the physique of aquatic animals; on the other hand, if drugs are used frequently, it will not only lead to the development of pathogen resistance, making drug prevention and treatment ineffective, but will also have toxic or irritating effects on whiteleg shrimp and destroy the microecological environment of the farming water body.

For rational drug use, the focus of work should be placed on “prevention first, combining prevention and treatment”. During the peak period of disease prevalence, according to the epidemic patterns of the disease, drugs that inhibit and kill pathogens, or drugs that improve the metabolic function of whiteleg shrimp, should be fed regularly to prevent the occurrence of diseases. The commonly used method is to mix drugs into the bait, such as adding certain antibiotics or Chinese herbal medicines (such as Radix Isatidis, rhubarb, garlic, Coptis chinensis, etc.) that are sensitive to pathogens, as well as certain vitamins and minerals. At present, in the farming process, the phenomenon of “valuing treatment over prevention” still exists. Once disease occurs, drugs are abused, thereby causing increased pathogen resistance.