Why Does Shrimp Farming Lose Money? Real Case Analysis
In order to summarize the experience and lessons of crayfish farming, the author recently surveyed more than 20 shrimp farming ponds covering nearly 1,000 mu in the urban area. According to the survey statistics, in 2011, 80% of shrimp farmers made a profit, with an average profit of 750 yuan per mu, and the highest reaching 1,050 yuan. But nearly 20% of farmers suffered losses, with the highest losses leaving them almost completely wiped out. The causes of shrimp farming losses are now summarized and analyzed, and relevant countermeasures are proposed for the reference of farmers.
I. Causes
1. Incomplete pond clearing. Zhou of Yuhuanggang Village, Xiuban, farmed continuously for 4 years, and the silt at the pond bottom was more than 0.5m thick. Each year when stocking shrimp fry, he only used quicklime or strong chlorine and other drugs for simple disinfection. As a result, after the fry were stocked, their feeding was abnormal and growth was slow, because ammonia nitrogen, nitrite and other toxic and harmful substances seriously exceeded the standard. Although bottom quality improvers and related biological agents were often used for regulation, because pathogens lurked in the pond bottom silt, shrimp diseases occurred frequently during farming, and repeated medication had poor results, leading to small adult shrimp size, low yield, high cost and losses.
2. Poor pond conditions. Yang of Lujiapu Village, Xiuban, used borrow pits from highway construction to farm shrimp without tidying them up. The pond embankments had poor water retention and flood control capacity, the pond bottom was uneven, and the water source was also not ideal. Not long after the fry were stocked, wind occurred, and some pond embankments had gaps and overflowed. Although nets were used for emergency blocking, wild fish and shrimp still mixed in, and after the wind period they could no longer be cleared. Wild fish and shrimp competed with crayfish for food, oxygen and space, and the inputs did not receive due returns.
3. Fry source not authentic. A certain farmer, believing the sweet talk of illegal shrimp fry dealers, bought shrimp fry from an irregular fry farm. Although the fry price was about 20 yuan lower per 10,000 tails than local fry farms, the fry had not undergone quarantine and brought in viruses. When the shrimp grew to 2-3cm, disease began and shrimp died, causing an outbreak of shrimp disease in the pond, and drug treatment was useless. Later it was learned that the dealer had resold the fry from an epidemic area, which was truly a case of losing more than one gained.
4. Poor feed quality. Some shrimp farmers, one-sidedly trying to save costs, chose low-priced inferior feed with incomplete nutritional components and unscientific proportions, causing malnutrition and seriously affecting shrimp fry growth.
5. Non-standard disease prevention and treatment. Some farmers did not carry out feeding management according to operating procedures, and were non-standard in pond clearing, disinfection, feeding, water quality management and disease prevention, causing continuous shrimp disease during farming. Moreover, after diseased shrimp appeared, they turned to any doctor in desperation, and the phenomenon of abusing and randomly using drugs was common. This not only failed to cure shrimp disease, but also caused water quality deterioration and drug residue problems.
II. Countermeasures
1. Strictly clear and disinfect ponds. Shrimp ponds should be drained every year, silt removed, weeds eradicated, embankments repaired, and inlet and drainage systems tidied. Shrimp ponds should be exposed to the sun for 15-20d until the pond bottom surface is dry, hard and cracked. Two weeks before stocking, first inject a small amount of water, dissolve 100kg of quicklime per mu and evenly spread it over the pond bottom, and use manual methods to rake the pond bottom silt once. After several days, add water to cover the entire pond bottom, then splash the whole pond with 2kg of chlorine dioxide and 50kg of soaked rapeseed cake per mu respectively. After 2-3d, release the disinfection water, dry the pond for 3-5d, and then inject new water after filtration.
2. Improve farming conditions. Basic conditions such as environment, area, water depth and water quality indicators must comply with the GB/T18407.4 standard. The water source must have no pollution, sufficient water volume, water quality complying with the NY5051 standard, and convenient intake and drainage. The shrimp pond should be rectangular, broad and sunny, with a flat bottom, sandy soil or loam. During shrimp growth, the pond water pH should be controlled within the range of 7.5-8.5, ammonia nitrogen below 0.1mg/L, nitrite below 0.1mg/L, dissolved oxygen above 5mg/L, bottom H2S not exceeding 0.1mg/L, organic matter content not greater than 5mg/L, and transparency maintained between 25-35cm.
3. Select high-quality shrimp fry. Before purchasing shrimp fry, investigate the fry farm's production license, reputation, source of parent shrimp, the farming situation of shrimp fry sold in previous years, and disease and medication conditions during seedling rearing. Before leaving the farm, shrimp fry must be tested by inspection and quarantine departments, and fry must not be brought in from epidemic areas to prevent the introduction of pathogens. In the same area, it is best to stock high-quality shrimp fry from the same fry farm, and never stock other shrimp fry that have not been tested.
4. Strengthen water quality management. During farming, appropriately add water and fertilizer to maintain a certain fertility of the water quality, regulate the composition of algae in the water, make green algae or diatoms become the dominant population, and form a certain quantity. Measure dissolved oxygen, ammonia nitrogen, nitrite, pH and other indicators once every 7-10d. If any indicator is unsuitable, take relevant measures promptly. One month after shrimp fry are stocked, use good microbial agents once every 10-15d to remove harmful substances in the pond; after two months of farming, attention should be paid to improving the bottom quality, such as using bottom quality improvers, turning on aerators to increase oxygen, etc.
5. Choose and feed good feed. Choose palatable nutritional feed varieties from manufacturers with large scale and stable quality to meet nutritional needs at each growth stage. Enhance shrimp immune function and resist pathogen invasion and sudden environmental changes. Feeding should adhere to many meals with small amounts, and supplement with live bait 1-2 times per week (small trash fish, snails, clams, corbicula meat, etc.). Also regularly add immune polysaccharides, shrimp multivitamins, etc. to the feed to enhance disease resistance and anti-allergy ability.
6. Scientifically prevent and treat diseases. Crayfish disease prevention and treatment should shift to prevention in many aspects, in management and health care. During farming, persist in morning and evening pond inspections to observe whether shrimp disease occurs, and also understand the occurrence of shrimp disease near and around the farming area, and take relevant measures promptly when problems are found. During the growth period, every 15-20d, use bromochloro hydantoin once to splash and disinfect the whole pond, or use quicklime for disinfection, but the amount and frequency should not be too much. Drug use in shrimp ponds should strictly implement the NY5001 and NY5007 standards.