Detailed Explanation of Key Management Techniques for Carp Cage Aquaculture

1. Selection of cage placement sites: The water area for placing cages should have fertile water quality, be sheltered from wind and exposed to sunlight, have a flat bottom, moderate depth (maintained at 4-7 m year-round), be free of pollution, have suitable water temperature, be free from floods, and be located near villages or in reservoir bay waters with relatively large farmland areas.
2. Structure and installation of cages
(1) Cage structure: Cages are usually made by sewing 6 pieces of netting into enclosed or open-topped box bodies, in rectangular or square shapes, with the sides fixed to frames bound with metal or square wooden strips. For fingerling-rearing cages, the mesh size is 1 cm, and the size is 20-30 sq m. For adult fish-rearing cages, the mesh size is 2-3 cm, generally around 60 sq m.
(2) Cage installation: Cages come in several forms, including enclosed floating type, open-topped floating type, and open-topped fixed type. Open-topped floating cages must have escape-prevention blocking nets added around the perimeter. Open-topped fixed cages must rise about 0.8 m above the water surface, and all cages must be installed securely.
3. Raising fingerlings in cages
(1) Intensive cultivation of summer fry: After carp are raised to the fry stage, they are divided among ponds for sparse rearing and rapidly cultivated in ponds to 4-5 cm, suitable for cage aquaculture.
(2) Screening and disinfection of fingerlings: Large-sized summer fry that have been cultivated must first be conditioned, then enclosed in nets for counting, and stocked by size in separate cages, with the full amount stocked at one time.
(3) Stocking fingerlings into cages: Before being put into cages, fingerlings must be disinfected by soaking in 3%-4% salt water for 5 minutes, or by soaking in a solution of 5% salt water and 0.5% baking soda, with the time depending on the tolerance of the fingerlings. The size for stocking carp is 4-5 cm, weighing about 3-5 g. The stocking density is 800-900 fish/sq m.
(4) Raising adult fish in cages: For raising adult carp in cages, the ideal size for stocked fingerlings is 50-70 g per fish, generally 30-100 g per fish, and the stocking density is 5-10 kg/sq m.
(5) Feeding management for cage-raised carp: Cage-raised carp rely on artificial feed, mainly compound feed. Training begins immediately after the fingerlings are put into cages, and feeding should be in small amounts and frequent. The particle size of the feed should match the size of the fingerlings, ensuring both reasonably complete nutritional composition and suitable size for consumption.