Summary of the experiment on the introduction and culture of Boleophthalmus

The big catfish is a small economic fish along the coast of warm and humid tropics. Like to inhabit the salty and fresh water waters of harbors and estuaries, muddy shoals in the intertidal zone, and dig caves, its meat is delicious and nutritious, so it is a characteristic variety with development prospects. In order to fill the gap of culture in this area, we actively introduced fish fry and carried out culture experiments in 2006. After months of exploration, the experiment was successful and basically mastered the culture technology. Now we briefly introduce the culture methods as follows.

I. the basic situation of the experiment

The experimental site @ # @ 185 is located in the farming community of Rongxing Township, Dawa County, Liaoning Province. Two standard ponds were used, with a total culture area of 10 mu and 3000 fingerlings of 4 cm per mu. After 153 days of artificial culture, the fish was harvested in early October.

II. Specific implementation steps

1. The preliminary preparation work first removes the silt from the bottom of the pond, then excavates the zigzag ring ditch with a depth of 0.5 meters, sprinkles the whole pool with 100 kg / mu of quicklime for disinfection treatment, enters the pool after 3 days of exposure, begins to fertilize and water 1 week before seedling release, uses 30 kg of new rice bran per mu of fertile water, then enters 20 cm of water, propagates benthic algae 3 days before seedling release, and finally sets up anti-escape facilities to surround the dike with plastic film. It is the same as @ # @ 235 years @.

two。 The seedlings were released on May 2, with a specification of 4 cm and 3000 seedlings per mu. Strict inspection and disinfection were carried out before seedling release. The fins of the seedlings are complete, the scales are complete, there is no mechanical damage, and the vitality is strong. Soak in 30 mg / L potassium permanganate solution for 20 minutes.

3. Culture management

(1) Feed organisms: the fish feeds on benthic diatoms or cyanobacteria and does not directly feed on rice bran, fish paste and so on. Cultivate benthic diatoms to ensure that the fish can eat enough bait in order to maintain the growth rate, so it is necessary to sun the flat and fertilize regularly. After a period of cultivation and management, the total length of fish fry reached more than 5 cm, and it was able to drill holes and live in caves. at this time, benthic diatoms disappeared and the water quality was muddy, so it was necessary to drain, sun and fertilize the diatoms to promote diatom reproduction. Drainage and fertilization, leaving only central ditch and ring ditch with water, choose sunny atmosphere to sun the flat for 2-3 days, and then apply rice bran. The amount of fertilizer application should be controlled flexibly according to the number of residual benthic diatoms. Usually 20-30 kg of rice bran is applied per mu. Sun the turf and fertilize once every 15-20 days.

(2) Water quality regulation: the big catfish is a wide-temperature and wide-salinity fish, which does not require high salinity and likes to live in brackish and fresh water. The salinity of pond water is 515 and the water temperature is 24,30 ℃. At the initial stage of stocking, in order to prevent the water temperature from changing too much, the water in the flat pond should be kept above 20 cm before the fry is drilled deeper. When the fish is more than 5 cm long, the fish burrows deeper and the water depth remains 5-10 cm. In case of cold wave attack on a cloudy day, new water is injected to maintain a deeper water level. In heavy rain or long drought season, it is necessary to change water or add fresh water in time to adjust the salinity of pool water.

(3) Daily management: during the cultivation period, the pond patrol is carried out every day to observe the feeding and growth of fish and the reproduction of benthic diatoms, and to prevent escape, theft and enemy damage at any time. Find problems and take timely measures.

(4) Disease control: the main enemies during the cultivation period are harmful birds and parasites. The old Gill net can be used as a Skynet to prevent harmful birds such as egrets from flying into the pond and preying on turbot. When parasites such as abdominal fluke are found on the fish, the trichlorfon extract can be sprinkled and killed in the whole pool, with a common dosage of 0.3-0.4 g / m3.

4. Results 26010 fish of 614kg were harvested in early October, with a recapture rate of 86.7%, an average specification of 23.6g and an average monthly weight gain rate of 156.7%.

The total cost is 26000 yuan, including 15000 yuan for seedlings, 1000 yuan for rice bran, 2500 yuan for labor, 1000 yuan for escape prevention, 1500 yuan for water and electricity, 2000 yuan for capital construction, 61000 yuan for medicine and 2000 yuan for others.

The average selling price is 60 yuan / kg, the total output value is 36800 yuan, and the total profit is 10800 yuan.

Third, experience

The results show that the fish has strong adaptability to the environment, high survival rate of culture, fast growth rate, monthly weight gain rate of more than 150%, suitable for the needs of culture production, short food chain and direct consumption of benthic algae to reduce feeding cost. no disease was found in the process of culture; the culture technology was relatively simple and easy to popularize; the economic value was high and the culture benefit was higher than that of other conventional varieties.

Although the experiment is successful, there are still some shortcomings: first, if large-scale breeding is to be carried out, a large number of fish fry will be needed, which will be transported centrally from the south, resulting in an inconvenient and high price to increase the breeding cost. therefore, this problem must be solved locally. We have selected a larger part of the fish to survive the winter, and we are ready to carry out the experiment of artificial breeding in the soil pond next spring. In the two years after the call, Wei successfully mastered the artificial breeding technology in the soil pond, and carried out mass production to provide healthy and high-quality fish fry for the area and the surrounding areas. Second, in terms of sales price, at present, consumers in the northern region do not have enough awareness of the nutritional value and medical value of bullets, which need to be further publicized and guided, so that the sales price is much lower than that of the southern provinces, if the same price is reached, we will get better economic benefits. In addition, the problem of bird damage was ignored in the prevention of escape and damage in the early stage of the experiment. due to the shallow water surface, many waterbirds entered the pond to prey on the fish, resulting in partial losses. When the problem is found, take countermeasures in time, the old Gill net is blocked at the top of the pool to do Skynet, harmful birds can not fly in, the effect is good.