Shrimp farming combined with tilapia reduces early mortality rate of shrimp

Ho Chi Minh City University of Agriculture and Forestry and the University of Arizona (USA) recently held a workshop to announce the cause of Early Mortality Syndrome (EMS) or Acute Hepatopancreatic Necrosis Syndrome (AHPNS). The most notable new issue here is information about the method of raising shrimp in combination with tilapia that can reduce the rate of early shrimp mortality.

Proposed integrated farming model

At the workshop, scientists confirmed that the cause of EMS is due to the bacteria Vibrio parahaemolyticus being infected with a virus called phage that spreads through the mouth into the digestive tract, then produces toxins that damage the hepatopancreas of shrimp.

According to Mr. Tran Huu Loc, Head of the EMS research team, a PhD student at the University of Arizona, his team has initially found a method to reduce the early mortality rate of shrimp, which is to combine shrimp with tilapia. However, in reality, this farming method has not been very effective because the shrimp are partly eaten by tilapia, and the tilapia compete with the shrimp for food. Mr. Loc said that he is looking for ways to overcome these limitations and this method will be announced after completing the testing phase.

Regarding this issue, Mr. Le Van Quang, General Director of Minh Phu Seafood Joint Stock Company, said that this enterprise is currently raising about 100 hectares of shrimp using the method of raising shrimp combined with tilapia. Initial results show that the mortality rate of shrimp is lower than before and the enterprise has partially overcome the phenomenon of tilapia eating shrimp as well as competing for food with shrimp raised in the same pond.

Previously, at the shrimp farming technical workshop held in Soc Trang when EMS syndrome was raging fiercely in the Mekong Delta and scientists had not yet found the cause, Professor Kevin Michael Fitzsimmon, Director of the International Agricultural Cooperation Agency, University of Arizona (USA), also recommended that shrimp farmers in the epidemic area should apply the model of polyculture, combining shrimp with many other aquatic species to restore shrimp farming.

Shrimp farming combined with tilapia is an effective solution
to save shrimp farming in disease-hit areas

Success in many countries

According to Professor Kevin Michael Fitzsimmon, the effectiveness of polyculture and integrated farming solutions has been proven in shrimp farming areas in many countries around the world. In Southeast Asia, countries such as Indonesia have applied the shrimp - tilapia model, Thailand has applied the shrimp - catfish and soft-shell crab model, the Philippines has applied the shrimp - tilapia farming model to help reduce pathogens and thereby restore shrimp farming.

However, some local officials are still concerned about the effectiveness of the integrated farming model because they think that the farming productivity is not high and the cost of feed investment will increase, leading to poor farming efficiency. Professor Kevin Michael Fitzsimmon said that this model not only helps reduce pathogens in the pond environment but also the productivity of products created from the model is very impressive. Specifically, the experimental model (under perfect conditions) of raising white-leg shrimp from tilapia pond water in Thailand has a shrimp productivity of up to 20 tons/ha and tilapia of up to 60 tons/ha.

In the mixed farming or mixed farming technical solution, farmers can use many different farming objects but have the effect of supporting each other such as: shrimp, fish, crab, seaweed... to put into the farming model. Currently, in the world, many mixed farming and mixed farming methods are being applied such as: raising fish in settling ponds, raising fish in cages in shrimp ponds, raising fish with shrimp in ponds, or the combined model of using tilapia farming water to raise shrimp, then using shrimp farming water to grow seaweed. In Vietnam, some shrimp farmers have also used tilapia to treat water in settling ponds to supply water to shrimp ponds with high efficiency.

Notably, in recent times, the model of co-culturing or combining tilapia with shrimp has become popular because of the practical effects that this fish species brings to farmed shrimp. Tilapia has the habit of mixing water layers in the pond, helping the pond bottom and water source to be better. Tilapia also eats organic debris in the pond, thereby helping to reduce the amount of waste in the pond, limiting the growth of harmful bacteria, and stimulating the growth of beneficial algae. In addition, tilapia also has the effect of destroying some intermediate hosts carrying pathogens and eating dead shrimp, thereby helping to limit the spread of pathogens in the pond.

According to (NNVN) - LC