Culture technology of sea bass

Sea bass is not only one of the common economic fish, but also a species for the development of marine aquaculture. At the same time, sea bass is also one of the important economic fish growing naturally. Artificial culture has a history of nearly 20 years. In recent years, driven by the market economy, sea bass culture technology has made a great breakthrough.

Culture of perch in pond

1. Pond conditions and preparation: the pond area should be 3300m2-6600m2, the water depth is more than 2m, the water source is sufficient, the water quality is pollution-free, and the water intake and drainage facilities are good and the transportation is convenient. Before stocking, dry ponds should be desilted, slope protection should be leveled, quicklime 750kg-1050kg per hectare should be used, pool water should be kept 10-20cm, and slurry should be soaked and sprinkled. Seven days later, the water was added to 1m deep. In order to keep the water quality in good condition, diammonium 75kg/hm2 could be applied once. After two days, the pond water turned oil-green and then it could be stocked.

2. Temporary rearing and stocking of sea bass: sea bass fry are mostly caught by sea at present, and about 2.5cm-4cm in spring. Fish body will be injured in different degrees after fishing and transporting operation. In order to improve the survival rate of culture, intermediate temporary culture can be carried out first. In the temporary culture mode, it is more convenient to set up 40 mesh cages in the pond. 2000-3000 seedlings per cubic meter of water, sterilized with 1 × 10-6-2 × 10-6 chloramphenicol, furazolidone after eating surimi. In the first 10 days, Artemia larvae or freshwater horns and copepods were fed, and then fresh surimi was fed. The fish species were cultured to about 10cm and put into the culture pond at the rate of 1.5ind / m ~ 2.

3. Nurturance management

① feeding: the bait is mainly low-breeding mixed fish, supplemented by artificial ingredients. The sea bass grabs food quickly and contains a lot of food, so it is very important to feed it regularly and quantitatively. When feeding, you should know that the fish are full without wasting bait. In each feeding, the amount of feeding should be increased when the fish is attracted to the surface to grab food, and the feeding should be stopped when the fish sinks and does not grab the food. the daily bait times and amount vary according to the season. The sea bass was fed 4-5 times a day in the suitable temperature season for rapid growth, 10-30% of the fish body weight, and 2-3 times a day in the early spring and late autumn of low temperature, accounting for 1-10% of the fish body weight.

② pond patrol inspection: patrol pond observation in the morning and evening, and deal with abnormalities in time. The contents of pond inspection include fish activity, changes in pond color, smell, transparency, pond escape prevention facilities and enemy damage, and so on.

Cage culture of sea bass

The main results are as follows: 1. Culture conditions: ventilation is required, water depth is more than 5m at low tide, flow is smooth, 0.3m per second, sediment is free of obstacles, water quality is fresh and pollution-free, and salinity varies little.

2. Cage structure: perch cage pipe frame fixed type and net body four corner sand settling bag type. The fixed type is a frame made of metal pipe that is slightly larger than the cage, and the cage is fixed; the sand bag type is a 4kg sand bag hanging at each of the four corners of the cage body to fix the net type. In the south, qualified fish rafts are made of wooden boards, floating on the water surface with floating balls, positioning with anchor cables, and cages hanging in the fish rafts. In the north, there are more single net and single floating frame, and each floating cage is connected to the positioning floating rope in the sea area. The net mouth size is usually 3 × 3m and 4 × 4m, and the net depth depends on the water depth of the sea area at any time, generally 4-6m, and the mesh depends on the size of the fish. the principle of selecting the mesh is to break the mesh without escaping the fish, and the mesh should be less than 1x2 of the height of the fish.

3. Fish stocking: sea bass are cultivated into commercial fish in that year, and their fry should be temporarily raised above 10cm and then counted and put into the cage. The number of water bodies in the cage should be 20-30 per cubic meter, and the specific stocking density should be determined according to the specifications of fish species, the conditions of the sea area in the morning and evening of the season, bait reserve and culture technical factors.

4. Bait: the bait is mainly low-value miscellaneous fish, and it can also be fed with a piece of bait. Each feeding should be less and then more, and then increase the amount of bait after leading the fish to the surface for food. The daily amount of bait should be full and not wasted. When the fish do not grab food, they should stop feeding. The daily baiting times were 4-5 times, and 2-3 times a day when the water temperature was low in early spring and late autumn.

5. Daily management: wash net elements frequently, remove attachments, usually once every 10-15 days, replace new cages if necessary, check cages frequently and strictly prevent escape and leakage. Pay attention to fish conditions, water conditions and diseases.

Disease control of sea bass

1. White candle disease of eyeball

[symptoms] are more common in spring and summer fish breeding stage. White spots appear in the eyeball, gradually expanding to cover the whole eyeball, and in severe cases, the eyeball is protruding and falling off. The disease can be caused by stale bait and vitamin deficiency.

[prevention and control] renew the aquaculture water body, feed fresh bait and add vitamins (especially VB).

2. Water mildew

[symptoms] Flocculent bacteria appeared in the fish, and the diseased fish swam slowly on the surface, lost appetite, emaciated and died, most of which were caused by infection after injury.

[prevention and cure] change new water, keep good water quality, dissolve 5-10min with 6 × 10-6 malachite green.

3. Skin ulceration

Symptoms are more common in the hot season. Local descaling, hyperemia and ulceration of the fish. Mostly caused by bacterial infection caused by fish injuries, diseased fish lose appetite, float slowly, lose weight and die.

[prevention] 20 × 10-6 chloramphenicol (or furacilin) medicine bath 4h-5h.

4. Enteritis

[symptoms] the diseased fish had abdominal distension, anal redness and swelling, yellow mucus outflow, weight loss, loss of appetite and severe death. It is caused by the deterioration of the food and the high fat of the diet.

[prevention and treatment] Furazolidone bait was prepared with 0.1% addition and fed continuously for 5-7 days.

5. Fish lice disease

[symptoms] the fish body parasites fish lice, the sick fish swim restlessly, rub against the pool wall, and the heavy fish lose weight and die.

[prevention and treatment] sprinkle the whole pool with crystal trichlorfon to make the water content up to 0.25 × 10-6-0.3 × 10-6, and apply it again every 3 days. Generally, the medicine can be cured twice, and the fish lice can also fall off by soaking in pure fresh water for 2-3 minutes.