Experience in shrimp farming crop 1: Good management of stocking density and water quality

(Baonghean) - Shrimp farming in the first crop this year took place in unfavorable weather conditions due to prolonged heat, slow growth of shrimp, and disease outbreaks in some areas. However, there are still households that achieved high productivity by applying VietGAP shrimp farming process. The lesson learned is to manage stocking density and water quality well.

The unusual weather, especially the prolonged hot weather, has caused shrimp farmers to face many difficulties. Especially from the beginning of May to the end of June, the heat was over 390C, the pond water temperature increased, causing the farming environment to fluctuate, affecting the health of the shrimp and developing some diseases. On the other hand, the price of commercial whiteleg shrimp decreased sharply, while the price of input materials for shrimp farming increased, affecting the economic efficiency of farmers.

In the first crop of 2015, Mr. Ho Dinh Thang's family in Chi Thanh hamlet, Quynh Bang commune (Quynh Luu) raised 1.7 hectares of shrimp, with 1.5 million shrimp in 5 ponds. Mr. Thang shared: "80% of the shrimp from the CP Company were harvested, but the 300,000 shrimp from the Viet Uc Company got sick after 45 days of release. The family harvested 1.8 tons and sold them for more than 90 million VND, just enough to cover the cost of shrimp and feed, and lost money on medicine, electricity, and hiring workers. The 3 ponds with 1.2 million shrimp from the CP Company alone yielded 7.4 tons and sold them for nearly 900 million VND, after deducting input costs, the net profit was more than 300 million VND. Having persistently raised shrimp for 15 years in this area, the first crop did not meet expectations, but it was still a crop that brought high profits to my family."

Quynh Thanh (Quynh Luu) people harvest shrimp.

Not everyone is as lucky as Mr. Ho Dinh Thang, Mr. Truong Hong Quang's family in Quyet Tien hamlet - Quynh Bang commune raises nearly 1 hectare of shrimp in the area of ​​Loc Thuy cooperative. With 3 ponds, he released 610,000 shrimp, the first crop just passed due to unfavorable hot weather leading to many diseases such as hepatopancreas, white spots, white feces. Although the family took good care of the shrimp, after 32 days of release, the shrimp got hepatopancreas disease and lost all 360,000 shrimp, the family had to destroy the disease, losing 150 million VND. Quynh Bang is the locality with the largest shrimp farming area in Quynh Luu district with 186 hectares, the people here have many years of experience in shrimp farming, the pond infrastructure is invested synchronously and guaranteed. Along with the strong development of shrimp farming in the area, more and more shrimp hatcheries have appeared, meeting the demand for shrimp, making it convenient for people to release shrimp on a large scale in time, there is no longer a shortage of shrimp at the peak of the season like previous years. However, in the first crop this year, the total harvest output of the entire Quynh Bang commune only reached 350 tons, equal to 50% of the output of the same period in 2014. Not only did the output decrease, this year, the price of commercial shrimp also dropped, at the lowest point the price was only 2/3 of 2014. In the 100 hectares of industrial shrimp farming area of ​​the commune alone, the profit and break-even rate reached 60%, while 40% lost capital.

According to Mr. Ho Nghia Dung, Chairman of the People's Committee of Quynh Bang Commune: "The management of breeds by the authorities is not good, there is not enough human resources to check and control the supply of breeds in the area. Meanwhile, farmers have not fully complied with the procedures when importing breeds, are still subjective, and sometimes even take the purchase of breeds lightly. Along with that, the farming environment is increasingly polluted, the direction of dredging the Mai Giang River has not been implemented yet. The project to bring seawater directly into the farming area has been surveyed and designed but has not been implemented. Local shrimp farmers are very much looking forward to this project, because for a long time they have had to take water from the Mai Giang River into the farming ponds, while wastewater from the ponds is also discharged there."

In the first crop of 2015, the whole district of Quynh Luu raised 465 hectares of shrimp, with a total harvest of 1,515 tons, and an average yield of 3.2 tons/hectare. According to Mr. Bui Xuan Truc, an officer in charge of aquatic products at the district's Department of Agriculture, the first crop of shrimp was quite good, but this year's price was lower than last year. At the main crop time, people could only sell for 80,000 - 90,000 VND/kg, so the profit was low. The whole district had 7.63 hectares of shrimp with white spot and hepatopancreas disease; more than 12 hectares had environmental diseases due to the heat and had to destroy the shrimp.

In Dien Chau, the entire district raised 126 hectares of shrimp for the first crop. By July 7, an epidemic broke out in an area of ​​12.48 hectares in Dien Trung, Dien Van, and Dien Ky communes, mainly due to acute hepatopancreatic necrosis syndrome. Farmers sprinkled lime around the banks of diseased shrimp ponds, the entrances to the farming areas, and destroyed shrimp to ensure compliance with the process, without affecting the local farming environment. According to the report of the Department of Agriculture and Rural Development, the area of ​​shrimp farming for the first crop in the whole province is 1,320 hectares, equal to 100% of the plan. In general, localities implemented the crop season according to the industry's schedule. According to many farmers, this year, households buying shrimp seeds from CP companies, the growth rate of the South Central region was equal to the average of many previous years, after 60 days of farming, the shrimp reached a size of 80 - 100 shrimp/kg. However, the growth rate of shrimp seed from some other suppliers is slow, many shrimp farming households only achieve 200 - 250 shrimp/kg in 60 days. The output harvested by the end of August is estimated at 3,405 tons, equal to 57% of the plan, equal to 99% over the same period. According to statistics from the Department of Animal Health in the area, the area of ​​shrimp farming with signs of disease in the whole province is 77.2 hectares. The average productivity of white-leg shrimp farming is 3.5 tons/ha (calculated by the farming water surface). Another difficulty for shrimp farmers this year is that the output is unstable, fluctuating in a downward direction, while the price of input materials increases, on the other hand, farmed shrimp is sick, traders are forcing down prices, affecting production efficiency.

With support from the Coastal Resources for Sustainable Development Project (CRSD), from 2013 to 2015, Nghe An Aquaculture Department successfully built white-leg shrimp farming areas following VietGAP process (each area was supported with 4-5 billion VND for infrastructure investment) in the communes of Quynh Thanh, Quynh Bang, Quynh Yen (Quynh Luu); Quynh Loc, Quynh Xuan (Hoang Mai Town) and Dien Trung (Dien Chau) with a total area of ​​220 hectares... In these farming areas, shrimp are stocked at low density, water and food resources are well managed, so farmers have a good harvest.

In general, the first crop of shrimp farming, on average, the whole province failed, but the farming areas still maintained their jobs, people continued to renovate ponds, preparing to release the second crop. For the second crop to be successful, shrimp farmers need to choose a source of quality, reputable shrimp seeds with quarantine certificates. Before releasing shrimp, it is necessary to check environmental factors such as pH, alkalinity, salinity... between the hatchery and the pond. If there is a difference, it must be adjusted to avoid shock to the shrimp seeds. Avoid releasing shrimp when it is sunny, the water temperature is high or when it is raining. The density of shrimp seeds should be lower than the main crop. Specifically, 50 - 60 shrimp/m2 for white-leg shrimp and 10 - 15 shrimp/m2 for black tiger shrimp. Farmers must regularly check the water environment factors in the pond, pay attention to factors that often fluctuate such as temperature, oxygen, pH... to adjust these factors to suit the shrimp and allowable fluctuations, not causing shock to the shrimp.

Quynh Lan