How to conduct cage culture of largemouth bass

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

1. Cage preparation and placement location

The cage is a Lishi-type double-layer covered cage, with specifications of 4 m×4 m×2 m, and mesh size 2.5 cm. The floating frame of the cage row is built from moso bamboo. The main walkway has two overlapping rows of moso bamboo, while the secondary walkway has a single row of moso bamboo, with 2 m between cages. The sinkers are cement blocks each weighing 1 kg, with 8 sinkers per cage. The bamboo raft is fixed with 6 concrete piers, each weighing 60 kg (the cage area is set according to need, generally 16-30 sq m is suitable). The cages can be set up in reservoirs, lakes, rivers, or ponds. Move the cages according to changes in water level so that the water depth at the cages remains above 3 m.

2. Culture methods

(1) Cage monoculture: Raise largemouth bass alone in cages, feeding bait regularly and in fixed amounts every day, resulting in relatively high output.

(2) Cage polyculture: Mainly culture largemouth bass in cages, while at the same time stocking suitable-sized silver carp and bighead carp fingerlings all at once. During the culture process, as the largemouth bass grow, the silver carp and bighead carp in the cage, which mainly feed on plankton, also continue to grow, so the largemouth bass in the cage have sufficient suitable bait and feed without external interference. Because the number of bait fish gradually decreases, the rearing density of largemouth bass can be kept 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 living area or auxiliary dam of a reservoir, or the deep-water area of a lake. Avoid setting cages in waters with rapid currents.

(2) Time of entry into the cage: This depends on local climatic conditions. When the water temperature reaches above 15 degrees C, fish fingerlings can be put into the 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 arrange the time for largemouth bass fry to enter the cages according to the breeding season of silver carp and bighead carp and the breeding season of their own food in the water body——plankton.

(3) Stocking density: For cage monoculture of largemouth bass, a density of 20-25 fish per sq m is suitable; for polyculture, the density is 6-8 fish per sq m. When bait fish such as silver carp and bighead carp enter the cages at the same time for polyculture, their density should be 250-300 times that of the largemouth bass fingerlings.

(4) Bait: Whether under monoculture or polyculture, the bait fish for largemouth bass must be suitable in size. If the body length of the bait fish is more than 70% of that of the largemouth bass, it will be difficult for the largemouth bass to prey on them; they cannot be swallowed, cannot be bitten through, and the bass may choke to death. If the individuals are too small, the number swallowed each day will be too large, which will increase feeding costs. The body length of the bait fish should be 30%-50% of the body length of the largemouth bass.

(5) Timely cage grading: The growth of largemouth bass is obviously uneven. Within a short time, the individual sizes of largemouth bass in the cage will differ greatly. To prevent cannibalism and to determine the size of bait fish, they must be graded and cultured according to different sizes. The mesh size of the cage should be based on the standard that bait fish do not escape. If the mesh is too small, water flow exchange inside and outside the cage will be poor, causing deterioration of water quality in the cage; if the cage is washed frequently, it will also increase the labor intensity of cage management. For first-stage largemouth bass culture cages, the mesh size is about 1 cm. When the largemouth bass grow to more than 100 g, they are transferred to second-stage cages for rearing.

(6) Daily management: Persist in inspecting the cages every day and clean them frequently. Wash 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 from escaping. During flood season, strictly guard against attacks by floods and heavy rain. According to weather forecasts, move the cages to a ventilated and safe place before floods and heavy rain arrive. Strengthen disease prevention and control work. Disinfect the largemouth bass before the fry enter the cages and when grading cages. The bait fed should be fresh and clean.