How to raise freshwater bass? Detailed explanation of high-yield farming techniques

Bass is one of the common economic fish and also a species developed for marine aquaculture. It is also known as spotted bass, bass board, huazhai, and so on. It is a fish of the family Moronidae and genus Lateolabrax. It has the characteristics of fast growth, wide adaptability, strong disease resistance, and delicious meat, and is deeply welcomed by people. Now let us take a look at high-yield farming techniques for freshwater bass.

Fry rearing

Bass fry caught from sea areas (body length 1.5-2 cm) must undergo desalination to a salinity of 4-7‰ before being put into a temporary holding pond (salinity 1‰). Starting on the second day after entering the pond, feed live bait such as zooplankton and bloodworms. Gradually mix fish paste and floating compound pellet feed with live bait and feed them together, gradually domesticating them until they are fed minced fish paste and floating pellet feed. During the temporary holding period, splash 0.3 ppm strong chlorine or 15 ppm formalin once a week for disinfection. For 3 days before starting feeding, give each 50 kg of fish 0.5 g furazolidone, 3 g oxytetracycline, and 1 g vitamin C orally, mixed with feed once a day. After more than 20 days of rearing, when they grow to 4-6 cm, they can be transferred to a large pond for rearing.

Water quality regulation

Bass is a bottom-dwelling fish and likes to live in water that is clean, has a relatively high dissolved oxygen content (4-6 mg/L), and has a transparency of 30-40 cm. New water should be added flexibly and promptly according to water color and transparency. In the early stage, because the fish are small and the temperature is low, water quality is easy to control, so the cycle for adding and changing water can be longer. As the fish grow and the pond biomass increases, pond inspections should be done frequently, new water should be injected often, and aerators should be used reasonably to increase oxygen. September to October, when the temperature is suitable, is the stage of rapid fattening for bass, and water quality regulation must not be neglected.

Pond construction

The pond area for bass farming should not be too large; 1-5 mu is suitable. The bottom should be sandy loam with little sludge, the pond bottom flat and slightly sloped toward the drain outlet, and the water depth 1.54 m. The drainage and irrigation system should be complete, and the water source should be sufficient, fresh, pollution-free, and of good water quality. After the pond is dried and exposed to the sun, release water to about 10 cm 10-15 days before stocking. Use 80-100 kg of quicklime per mu, and the next day add another 5 kg of bleaching powder, dissolve in water and splash over the whole pond for pond clearing and disinfection.

Seedling stocking

After desalination treatment and rearing until the body length reaches about 10 cm, bass seedlings are put into ponds for grow-out culture. The survival rate is high. Stocking size should be as uniform as possible to prevent cannibalism. The stocking density is suitably 1000-1500 fish per mu, and at the same time, 40 large-size bighead carp fingerlings, 20 silver carp fingerlings, and 200 Pengze crucian carp are stocked together to make full use of the water body, regulate water quality, and increase yield.

Feeding management

After screening, bass fry are raised separately by size in different ponds. The stocking density is generally 2500-3500 fish per mu, with a water depth of more than 1.5 m. Maintain suitable pond water fertility, with transparency of 30 cm and water color oily green as suitable. Feed twice a day. The main feed is minced fish paste and floating pellet feed. Vitamin B and C should be added to the feed. The daily feeding amount is 6% of fish body weight. Every month, mix oxytetracycline, erythromycin, and vitamin drugs with bait and feed twice, each time for 3 consecutive days. At the same time, regularly splash 0.4 ppm strong chlorine or 20 ppm formalin over the whole pond for disinfection. Do a good job of pond inspection management every day, turn on aeration at night or when the weather is muggy and air pressure is low, and drain and replace water in time if pond water deteriorates, keeping the pond water fresh.

Disease control

1. Eye opacity disease

[Symptoms] Mostly seen in the fry and fingerling stage in spring and summer. White spots appear on the eyeball and gradually expand to cover the entire eyeball. In severe cases, the eyeball protrudes and falls off. It can be caused by stale bait and vitamin deficiency.

[Prevention and treatment] Renew the aquaculture water body, feed fresh bait, and add vitamins to the bait (especially B).

2. Saprolegniasis

[Symptoms] Flocculent bacteria appear on the fish body. Sick fish float to the water surface and swim slowly, have poor appetite, become emaciated, and die. Most cases are caused by infection after injury to the fish body.

[Prevention and treatment] Replace with new water and maintain good water quality. Bathe with 6×10-6 malachite green for 5-10 minutes.

3. Skin ulcer disease

[Symptoms] More common in high-temperature seasons. Local scale loss, congestion, and ulceration occur on the fish body. It is mostly caused by bacterial infection after injury to the fish body. Sick fish have poor appetite, float up and swim slowly, become emaciated, and die.

[Prevention and treatment] Bathe with 20×10-6 chloramphenicol (or furacilin) for 4-5 hours.

4. Enteritis disease

[Symptoms] Sick fish have abdominal distension, red and swollen anus, and yellow mucus flowing out. The fish become emaciated, have poor appetite, and severe cases die. It is caused by spoiled bait and high fat content in the bait.

[Prevention and treatment] Prepare furazolidone medicated bait at an inclusion rate of 0.1% and feed continuously for 5-7 days.

5. Fish louse disease

[Symptoms] Fish lice parasitize the fish body. Sick fish are restless, rub against the pond walls, and in severe cases the fish become emaciated and die.

[Prevention and treatment] Splash crystal trichlorfon over the whole pond so that the pond water reaches a drug concentration of 0.25×10-6-0.3×10-6. Apply the drug again after 3 days. Generally, two treatments can cure it.

6. Black body disease

[Symptoms] The onset season is April to June. Fry and fingerlings with a body length below 1O cm are susceptible to this disease. Sick fish are black and thin, do not feed, respond slowly, and often drift on the water surface.

[Prevention and treatment] There is no effective prevention and treatment method yet. Seedling quarantine should be strengthened, and sick fish should be isolated and destroyed in time.