Vietnamese scientists have successfully built the process of raising lobsters on shore, shrimp live healthy, grow quickly, bring high profits despite the 20% reduction in investment.
Dr. Mai Duy Minh, Research Institute of Aquaculture 3 said that raising lobsters on land by tanks is not a new technology in the world, but has not been studied in Vietnam. From 2016 the Institute started to research this technology, tested and perfected it, and transferred it to Dac Loc Seafood Co., Ltd.
From June 2018 to December 2020, this technology was applied to the development of a commercial-scale onshore lobster farming project in the intertidal zone of Phu Yen province. Over time, new technology brings higher efficiency than traditional farming.
According to Dr. Minh, in order to raise lobsters on tanks, the water must always meet the requirements of shrimp growth and development. This is not easy, even for shrimp raised in cages, because shrimp waste and organic matter in the feed make the water environment polluted continuously, causing shrimp to die. The technology of recycling water reuse (RAS) was then researched and applied by scientists.
The rearing tank system is redesigned, including a waste settling tank, biological filter tank, water quality standardization tank, equipment system such as filter drum, skimmer, UV, water temperature stabilizer...
Shrimp farming water is continuously filtered by a pump, from the culture tank to the settling tank, pumped to the filter tank and then back to the rearing tank before being cleaned and disinfected with UV light. "The key technology here is the biological filter," said Dr. Minh.
Lobster rearing system in onshore reuse water tanks (RAS). Photo: NVCC
Lobster rearing system in onshore reuse water tanks (RAS). Photo: NVCC
The biological filter tank is filled with filter media - that is, the media for the growth of microorganisms. At the same time, the filter tank is arranged with air blowers to ensure water convection. Two species of microorganisms, Nitrosomonas and Nitrobacter, will be added to help them adhere to filter materials and water treatment. In shrimp culture water with a lot of floating protein, one microorganism will break down the protein into NH3, then a second microorganism will break down NH3 into NO2 and NO3. Each filter tank is designed in the form of adjacent compartments, with three or more compartments.
The tank is equipped with an environmental warning system to monitor temperature, pH, salinity, dissolved oxygen... According to calculations, with a tank of about 2,100kg of shrimp, it needs a water flow of 1,470 m3/day.
Lobsters are kept in tanks. Photo: NVCC
Lobster raised in tanks grows fast and strong. Photo: NVCC
The aquarium is also designed with a thermostat system with a heat exchanger to ensure that the water temperature is always between 27 and 28 degrees Celsius even when the outdoor temperature is 36-38 degrees Celsius. This helps the shrimp not to get sick. affected by weather, limiting shrimp mortality. This technology is cheaper than imported technology about 5 times.
Because the circulating filter system works continuously, the circulating shrimp tank does not need to change the water. But to stimulate shrimp molting, the research team tested and found that every 15 days, 100% of the water in the tank was changed for small shrimp under 100 g/head and 50% for large shrimp over 100 g/head. help increase production efficiency. Shrimps are also bathed in 40 ppm hydrogen peroxide for 10 minutes/month to prevent bacterial and parasitic diseases. Weekly adding microorganisms to the filter compartments of the biological filter tank.
The team also developed a process to produce pellets for lobsters. These pellets are made from fish meal and flour, fragrance and some binders so that the food does not dissolve too quickly in the water, helping the shrimp grow and develop well. Mastering the production process of dry food for lobsters helps in easy traceability, meeting export requirements. During the rearing process, fresh food will be mixed with dry food to ensure the best growing conditions for shrimp.
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