Intensive Cage Culture Techniques for Largemouth Bass

Using cages for intensive culture of largemouth bass can also achieve excellent economic benefits. Cages can be set up in reservoirs, lakes, rivers, or ponds.

1. Cage preparation and placement. The cage is a Lishi-type double-layer covered cage, with specifications of 4 m×4 m×2 m, and mesh size of 2.5 cm. The floating frame of the cage row is made of moso bamboo, with the main walkway using double rows of overlapping moso bamboo, and the secondary walkway using a single row of moso bamboo, with cages spaced 2 m apart. The sinkers are cement blocks each weighing 1 kg, with 8 sinkers per cage. The bamboo raft is fixed with 6 cement piers, each weighing 60 kg (the cage area is set according to needs, generally 16-30 sq m is suitable). Cages can be set up in reservoirs, lakes, rivers, or ponds. Move the cages according to water level changes to keep the cage water depth above 3 m.

2. Culture methods. 1. Cage monoculture: Raise largemouth bass alone in cages, feeding bait at fixed times and quantities every day, yielding relatively high production. 2. Cage polyculture: Mainly culture largemouth bass in cages while stocking suitable-sized silver carp and bighead carp fingerlings all at once. During the culture process, as the largemouth bass grows, the plankton-feeding silver carp and bighead carp in the cage also continue to grow, so the largemouth bass in the cage has sufficient suitable bait and can feed without external disturbance. As the number of bait fish gradually decreases, the stocking density of largemouth bass can be maintained within a relatively reasonable range.

3. Culture techniques.

1. Water surface selection: Generally choose the middle and upper reaches of the main river channel, near the residential area or auxiliary dam of reservoirs, or the deep-water area of lakes. Avoid setting cages in waters with swift currents.

2. Time of entry into cages: This depends on local climate conditions. When water temperature reaches above 15°C, fingerlings can be put into cages. The earlier the time, the better, as it can increase growth time. Consider the source of bait fish. If silver carp and bighead carp fry are used as bait for polyculture, then consider the breeding season of silver carp and bighead carp and the breeding season of their own food in the water — plankton — to arrange the time for largemouth bass fry to enter the cages.

3. Stocking density: For cage monoculture of largemouth bass, the density is suitably 20-25 fish per sq m; for polyculture, the density is 6-8 fish per sq m. Bait fish silver carp and bighead carp enter the cages for polyculture at the same time, with a density suitably 250-300 times that of largemouth bass fingerlings.

4. Bait: Whether monoculture or polyculture, the bait fish for largemouth bass must be suitable in size. If the bait fish body length is more than 70% of the largemouth bass, the largemouth bass will have difficulty preying on it, cannot swallow it, cannot bite it apart, and may get stuck and die. If the individual is too small, the daily number of bait consumed will be too large, increasing feeding costs. The bait fish body length should be 30%-50% of the largemouth bass body length.

5. Timely grading into separate cages: Largemouth bass growth shows obvious unevenness. Within a short time, the individual sizes of largemouth bass in the cage will differ greatly. To prevent mutual predation and to determine bait fish specifications, they must be reared in grades according to different size specifications. The cage mesh size should be based on the standard that bait fish cannot escape. If the mesh is too small, water flow exchange inside and outside the cage will be poor, causing water quality deterioration inside the cage. If the cage is washed frequently, it will also increase the labor intensity of cage management. For first-level largemouth bass culture cages, the mesh size is about 1 cm. When largemouth bass grow to more than 100 g, they are transferred to second-level cages for rearing.

6. Daily management: Persist in inspecting the cages every day and cleaning them frequently. Clean the cages once every 15 days to maintain smooth and fresh water exchange. If rat holes or damage are found in the cages, repair them promptly to prevent fish escape. During flood season, strictly guard against floods and rainstorms. According to weather forecasts, move the cages to ventilated and safe places before floods and rainstorms arrive. Strengthen disease prevention and control work. Disinfect the largemouth bass before fry enter the cages and during grading. The bait fed must be fresh and clean.