Cage Culture Methods and Technical Key Points for Sturgeon

The sturgeon series varieties have the characteristics of wide adaptability, fast growth, short culture cycle, good market prospects and high economic returns. Using cages to culture sturgeon is a very good intensive production method. Compared with pond culture of sturgeon, it has the following advantages: large water exchange volume, sufficient oxygen supply, fish are not prone to disease, and the survival rate and yield of culture are high; feeding management is centralized and convenient, fish capture is easy, and fish can be harvested in a timely manner as needed, which helps regulate the market; the fish has good eating quality, no muddy taste, and excellent commercial quality; it saves expenses on water, electricity and labor, reduces unit costs, and helps with competition in market prices. For commercial cage culture of sturgeon, attention should be paid to grasping the following technical methods:  

Choose a good water area 

For cage culture of sturgeon, choose areas in medium and large water bodies such as reservoirs, lakes and rivers that are sheltered from the wind and face the sun, have a broad water surface, small waves, water depth of more than 5 m, slight flowing water, fresh and pollution-free water quality, and dissolved oxygen content of more than 5 mg per liter. At the same time, note that it is necessary both to avoid the main navigation channel and to have convenient transportation.  

Arrange the cages 

Cages are mostly double-layered and made from polyethylene or polyvinyl chloride netting. The specifications depend on the scale, and the common lengths and widths are 10 m × 4 m, 6 m × 4 m, 5 m × 4 m and 4 m × 3 m, etc., with a cage height of 3-4 m and a water entry depth of 2.5-3.5 m. The mesh size varies with the size of the fingerlings, following the principle of preventing fish escape and facilitating water exchange. Generally, for sturgeon fingerlings with a body weight of 20-50 g, the mesh size is 1.2-1.6 cm, and for those with a body weight of more than 100 g, it is 2-3 cm. The bottom of the cage should be sewn with fine-mesh bolting silk netting as a feeding platform to prevent feed loss. The cages are generally of the frame floating type, supported by floating drums and fixed with ropes, able to rise and fall freely with water level fluctuations, and should be installed and put into the water 7-10 days before fish release to allow algae to attach, so as to avoid abrasion of the body surface and skin of the fingerlings after they enter the cages. Generally every 4 cages form one group, and the spacing between groups is more than 2 m.  

Reasonable stocking 

Sturgeon fingerlings are suitable for stocking in winter and spring, and are required to be robust, uninjured and disease-free, lively in swimming, and large and uniform in size. Stocking density per square meter of cage: for fingerlings with a body weight of 30-50 g, 60-80 fish, and for fingerlings with a body weight of 100-200 g, 20-40 fish. During stocking, soak and wash the fish body with 3% salt water for 10-15 minutes.  

Scientific feeding 

For sturgeon culture, complete formula pellet feed must be fed. The feed nutritional standard is: protein content of about 40%, of which animal protein accounts for more than 15%, fat about 9%, carbohydrates about 30%, as well as appropriate amounts of vitamins, minerals, cellulose, etc. The feed should be palatable, and the particle size should not be too large or too small; generally 1/2 of the fish mouth opening is good. Do not feed within 2 days after the fingerlings enter the cage, so that they can adapt to the cage environment; feed after 2 days, feeding 5-6 times per day, evenly scattered over the whole cage. Generally after 7 days, sturgeon will readily eat the compound pellet feed. Once entering the normal feeding stage, feed 3 times per day, at 7-8 a.m., 11 a.m.-12 noon and 6-7 p.m., each feeding lasting 15-20 minutes, adhering to the "four fixed" principle and the "small amount, many times" feeding method, to ensure that every fish can eat feed. Daily feeding amount: below 20°C water temperature, 0.5%-1.5% of fish body weight; at 20°C-30°C water temperature, 2%-5%. Specifically, it should be reasonably adjusted according to weather, water temperature, changes in dissolved oxygen in the water, and the feeding and growth conditions of the fish.  

Strengthen management 

Cages must have dedicated management and protection, insist on inspections in the morning, noon and evening, keep daily records of air temperature, water temperature, feeding and diseased or dead fish, carefully observe the activity and growth of sturgeon, and when differences in size appear among individuals, divide them into different cages in a timely manner to avoid polarization. Ensure cage safety, strictly prevent wind and waves from driving the cages, enemies from damaging the cages, and mud and debris from pressing down and sinking the cages, and frequently check whether there are holes in the cages; if there are, repair them in a timely manner to prevent fish escape. Regularly scrub the cages, generally cleaning once every 7-10 days, and especially immediately after floods, to ensure smooth water exchange inside and outside the cages. Earnestly grasp fish disease prevention and control, and usually whenever dead or injured fish are found, remove them as soon as they are seen to prevent pollution or mutual cross-infection. Every 20 days, use 15 g of quicklime and 0.3 g of dibromohydantoin per cubic meter of water alternately, dissolved in water and splashed over the cage water body and nearby waters, to prevent fish diseases. If parasitic diseases such as Trichodina, Ichthyobodo and Epistylis occur, use 2 g of potassium permanganate per cubic meter of water, diluted with water and splashed over the whole cage; if bacterial enteritis occurs, add 0.2% furazolidone or allicin to the feed and feed continuously for 5-6 days, with good prevention and control effects.