High-yield culture techniques of freshwater perch

Sea bass is one of the common economic fishes, and it is also a species for the development of marine aquaculture, also known as sea bass, sea bass, Huazhai and so on. It has the characteristics of fast growth, wide adaptability, strong disease resistance, delicious meat and so on. It is deeply welcomed by people. Let's take a look at the high-yield culture techniques of freshwater bass.

Seedling cultivation

The sea bass seedlings caught from the sea area (body length 1.5 ~ 2cm) should be desalinated to 4 ~ 7 ‰ before they could be put into the temporary culture pond (salinity 1 ‰). On the second day of the pond, fresh baits such as zooplankton and red worms were fed, and the fish pulp, floating particles and fresh bait were gradually domesticated to minced surimi and floating pellets. During the temporary rearing period, 0.3ppm strong chloroform or 15ppm formalin was sprinkled and disinfected once a week. Three days before feeding, every 50 kg fish were fed with 0.5g of trimethoprim, 3g of oxytetracycline and vitamin C1g, once a day. After more than 20 days of feeding, they can enter the pond when they grow to 4cm.

Water quality regulation

Bass is a benthic fish, like to live in clean, high dissolved oxygen (4mg / L) and transparency in 30cm and 40cm. New water should be injected flexibly and timely according to water color and transparency. In the early stage, because the fish is small and the temperature is low, the water quality is easy to control, and the cycle of adding and changing water can be longer. With the growth of fish and the increase of fish pond biomass, the pond should be patrolled frequently, new water should be injected frequently, and aerator should be used reasonably to increase oxygen. The temperature from September to October is suitable for the rapid fattening stage of sea bass, and the regulation of water quality should not be ignored.

Pond construction

Sea bass culture pond area should not be too large, 1 mu is suitable, sandy loam bottom, less silt, flat bottom, slightly inclined to the outlet, water depth of 1.54 meters, drainage and irrigation system is perfect, sufficient water source, fresh, non-pollution, water quality, good. The pond was exposed to the sun in the dry pond, about 10 centimeters of water was released 10 to 15 days before stocking, 80 kilograms of quicklime was used per mu, and 5 kilograms of bleaching powder was added the next day, and the whole pond was sprinkled with chemical water to clear the pond for disinfection.

Seedling stocking

After desalination treatment, the adult sea bass fingerling is about 10 cm long and put into the pond for adult fish culture. the survival rate is high, the stocking specification is neat, so as to avoid eating each other, and the stocking density is 1000-1500 per mu. At the same time, 40 large bighead carp, 20 silver carp and 200 Pengze crucian carp were cultured in order to make full use of the water, regulate the water quality and increase the yield.

Feeding and management

The sea bass fry are raised in ponds according to the size after sieving. The stocking density is generally 2500 to 3500 / mu, the water depth is more than 1.5 meters, and the suitable fertility of the pond water is maintained. The transparency is 30 cm and the water color is oil-green. Twice a day, the main feed is minced surimi and floating pellet feed, vitamin B and C should be added to the feed, and the daily feeding amount is 6% of the body weight of the fish. The baits of terramycin, erythromycin and vitamins were fed twice a month for 3 days. At the same time, the whole pond was disinfected regularly with 0.4ppm strong chlorine or 20ppm formalin. Do a good job in pond patrol management every day, turn on the machine to increase oxygen at night or when the weather is hot and low pressure, and find that the pool water should be discharged and changed in time to keep the pool water fresh.

Disease prevention and cure

1. White candle disease of eyeball

[symptoms] more common in the spring and summer fish seed stage, the eyeball appears white spot, gradually expand to cover the whole eyeball, severe exophthalmos fall off, which can be caused by fresh bait and vitamin deficiency.

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

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 treatment] replace new water, keep good water quality, dissolve malachite green with 6 × 10-6 malachite green for 5 minutes for 10 minutes.

3. Skin ulceration

[symptoms] most common in high temperature season, fish body local descaling, hyperemia and ulceration, mostly caused by bacterial infection caused by fish injury, diseased fish loss of appetite, floating slowly swimming, emaciation and death.

[prevention and treatment] 20 × 10-6 chloramphenicol (or furacilin) was bathed for 4 hours for 5 hours.

4. Enteritis

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

[prevention and treatment] Furazolidone bait was prepared with 0.1% addition and fed continuously for 5 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] the whole pool was sprinkled with crystal trichlorfon to make the water content up to 0.25 × 10 ~ (- 6) × 10 ~ (- 6) and 0.3 × 10 ~ (- 6). Once every 3 days, it can be cured by two times.

6. Blackbody disease

[symptoms] from April to June, seedlings with a body length of less than 10 cm are easy to be infected with the disease. Diseased fish are black and thin, do not feed, are slow to respond, and often dissociate from the surface of the water body.

[prevention and control] there is no effective control method, so seedling quarantine should be strengthened, and diseased fish should be isolated and destroyed in time.