Not only is the farming model of shrimp, crab and mullet suitable to earthen ponds of the tidal areas when the balance of the ecosystem in water is disrupted, but it reduces risks.
The Agricultural Service Center in Bình Sơn of Quảng Ngãi has been implementing the project “Build an aquaculture area in combination with climate change adaptation” in Bình Dương commune. This three-month long project is participated by five households in the 2-hectare farming area. The district supports broodstocks, feed and development costs of 180 million dong. A total of 10 thousand of crabs, 800 thousand of white leg shrimps and 6,000 mullets have been provided to farmers.
The farmed species have brought high economic value and helped balance the ecosystem, stabilize the grow-out ponds and reduce possible risks of disease outbreak.
According to technical officers, the density should be: 40 white leg shrimps/m2, 01 marine crabs/m2 and 01 mullets/3m2. Crabs and mullets should be stocked one month before stocking post larvae because the growth cycle of the first two species is longer. After one month of stocking, crabs and mullets grow well, helping purify the bottom of the pond, triggering good algae and ephemera, and stabilizing criteria of water.
Households, who own some ponds, spend one small pond for shrimp nursery within 20-30 days before shifting them to grow with crabs and mullets. If one pond is available, farmers can use a mesh to divide one fourth of the pond for shrimp nursery. After 20-30 days, the mesh can be removed so that shrimps, crabs, and mullets can grow together.
Specific feed should be used for shrimps and low value fish. Feed size and protein amount are decided by the growth period of species. Industrial feed can be used for crabs and shrimps. However, low value fish should be used as feed for crabs so that they weigh up fast. Mullets can use a part of shrimps’ feed, algae and organic sludge in the pond.