Key technologies for pond culture of big-bolus fish

I. Selection and Construction of Farming Sites

The large-scale fish-bearing fish culture sites should be selected from nearby areas where there is no industrial pollution source, there is a moderate amount of fresh water injected into the inner bay high tide area or the coffered low-lying land. Water quality: The required proportion of moderate, salinity 5 ~ 15, pH 7.5 ~ 8.6, rich in nutrients, is conducive to algae breeding. Bottom quality: It is better to use muddy or silty clay soil. The mud depth is about 30cm, which is convenient for the drilling hole of the big mudskipper.

The area of ​​the aquaculture pond is 3 to 5 mu. It is advisable to use a large pond, if it is too big, it is difficult to put enough seeds at one time. The daily management is inconvenient, and if it is too small, it is not conducive to the growth of the mudskipper fish. The shape of aquaculture ponds can vary with the terrain, either rectangular or square. The aquaculture pond structure is similar to the fish, shrimp, crab and aquaculture ponds. The central ditches and ring ditch with a depth of 0.5m are dug in the ponds, and the fish are inhabited when the tarmac is used. Or dig a ditch around, the central beach will be flattened and the floor width will be 3 meters. A 0.8 meter high fence or other anti-escape equipment will be added around the pool to prevent the escape of large marble fish and other animals. The bottom of the pool is flat and slightly inclined toward the outlet to facilitate fertilization, drying, and cultivation of benthic diatoms.

Second, pond clearing and seedling stocking

Before the seedlings were stocked for 1 to 2 months, the ponds were properly dressed and disinfected. Disinfection can be quicklime or bleaching powder, according to the size of the pool to calculate the amount of the drug, the usual concentration of lime is 375 ~ 500ppm, bleaching powder is 30 ~ 50ppm, into the emulsion Quanchiposa, remove the enemy enemy creatures.

After the efficacy disappears, choose sunny day to drain the pool water, and continuously expose it for 3-5 days. After the bottom of the pool is dried to a slight crack, apply the base fertilizer in time to cultivate the algae as the pre-feed for the fish. The method is to ferment 40-50 kg of organic fertilizer such as livestock manure per mu, or 20 kg of rice bran. Fertilizer should be selected on a sunny day without wind, and the fertilizer should be evenly spread on the site. Be careful not to pile up, and fill 15 cm of water after fertilization. Generally, after 3 to 5 days, the algae grows gradually to form a bed of algae, and the algae bed is preferably yellow-brown diatom and tender green silicon.

Most of the seedlings currently stocked by the mudskipper are derived from natural seedlings collected in the sea area and artificial seedlings from the earthen ponds. Stocking fry: Requirements of the fins intact, scales complete, no mechanical damage, strong vitality. Restocking season: Usually spring or fall stocking is optional. The spring stocking is the large-sized seedlings that passed through the winter last year. The total length is 4 to 6 centimeters, and 3000 to 5000 tails are stocked. The stocking in the fall is the small size seedlings that were bred in that year, and the total length is 2 to 4 centimeters. 8000 to 10,000 tails. Because the mudskipper fish will not be the same type of residue, for the moment can not be enough to fill in the seed, can be adopted in batches of stocking, capture large and small.

Third, the daily management of adult fish farming

The giant salamanders feed on benthic diatoms or cyanobacteria and do not feed directly on rice bran or fish paste. The benthic diatoms should be cultivated to ensure that the large salamanders can eat enough food to maintain the growth rate. Therefore, it is necessary to frequently use the drying floor and fertilize. After a certain period of incubation and management, the fry can be drilled for more than 5 centimeters. The benthic diatoms have disappeared and the water quality has become muddy. It is necessary to drain the water, dry the floor, and fertilize it to encourage diatom breeding. Drainage drying floor, fertilization, leaving only the central ditch and ring ditch water, choose sunny weather, dry floor 2 to 3 days, and then Shi dynamic Dan, Pei Shui Po or rice bran. The amount of fertilizer depends on how much fertilizer and residual benthic diatoms are. Usually, per acre Shi dynamic Dan or Shuishuibao 0.5kg, or rice bran 10-15kS per acre. 15 to 30 days drying floor, fertilization once.

The big salamander is a wide-temperate, wide-salinity fish. It does not require high seawater salinity. It prefers to live in brackish waters. The salinity of pool water is 5 to 15, and the water temperature is 24 to 30°C. At the beginning of the stocking period, before the fish fry were drilled deeper, in order to prevent the water temperature from changing too much, the surface water should be kept at 15 cm or more. When the fish is more than 5 centimeters long, the fish will play deeper and the water depth will be 5 to 10 centimeters. When the cold wave strikes in cloudy days, new water is injected to maintain a deeper water level. In heavy rainstorm or long drought season, it is necessary to change the water or add fresh water in time to adjust the salinity of the pool water.

During the cultivation period, a patrol pond is performed every day to observe the growth of the fish’s feeding habits, and the breeding conditions of the benthic diatoms are well protected from escaping, burglary, and predators. Find problems and take timely measures.

The predators during the development of the giant salamander are mainly harmful birds and parasites. Old thorn nets can be used as sky nets to prevent the death of egrets and other harmful birds in the pool and to prey on the big bullet fish. When parasites such as abdomen flukes are found on fish, they can be washed and killed by the Chinese herbivorous ichthyosis leaching solution, and the amount used is 0.3 to 0.4 ppm.

Fourth, arrest and living transport

The collection of large-scale mudskipper fish can be carried out all year round. Usually, the time of arrest is determined according to the market conditions to ensure that the large-scale mudskipper fish sells at a good price. As long as the size of the cultured fish is up to 30 to 40 tails per kilogram, it can be supplied to the market.

Harvesting can be carried out by cage trapping, stepping on the net, hand dip net, gill net fishing and other methods. Pond culture currently uses most of the cage nets and gill nets for fishing.

The large salamander fish can be collected and transported in vivo. The method is relatively simple. As long as a small amount of water is added to keep the fish wet, it can be transported over long distances. Transport is often made of special circular sieve trays, with a diameter of 80 cm and a depth of 20 cm. A plastic film is laid on the bottom of the sieve tray. After the fish is put in, add a small amount of water and several sifting sieves overlap. According to the above method, transported on the way for 48 hours, the survival rate can reach 95% to - on.