Experiment on culture of sampan fish in cement pond

1 materials and methods

1.1 sources of test fish

On May 12, 2001, sampan species were shipped from Indonesia and transferred through Malaysia and arrived at the test site at 5 pm on the 14th. 3000 test seedlings were transported with oxygen in 6 bags and 3 boxes of live water bags. Upon arrival, only 1380 fry survived and the survival rate was only 46%. The fry put in the fry pond died one after another in the second and third days, and only more than 500 survived, due to the long transportation time and the death caused by carbon dioxide poisoning.

1.2 conditions of test pool

The test pool is an outdoor cement pool of 6 × 12 × 1.5m3, with cement substrate, flat bottom, convenient injection and drainage, water source from Xinglin Bay Bantou Reservoir, fresh water quality, sufficient water quantity, pH of about 7, dissolved oxygen above 5mg/L, cleaning and disinfection before seedling release, water depth of 0.8m, filtration and injection, cultivation of water quality.

1.3 stocking of seedlings

The fish fry were transported to the stocking site, the water temperature was adjusted by 20min in the experimental pond, the fish was released from the bag, and the water temperature was 26.5 ℃. After the fry were temporarily raised in the net bucket in the experimental pond, the dead and injured fry were removed and counted into the pond. At the same time, the average body length 3.27cm and body height 1.28cm were measured by sampling, no parasites were detected on the body surface, and there was a small amount of silt in the Gill filaments.

2 daily management

During the period of culture, we should pay attention to three levels: first, fish fry transportation and cultivation; second, feeding and management; third, disease prevention and control.

In daily management, try to achieve first diligence (patrolling pool), second elimination (water disinfection, tool disinfection), three looks (watching fish activities, feeding, water color), four determinations (timing, positioning, quality, quantitative feeding), and five precautions (disease prevention, escape prevention, theft prevention, waterproof change, enemy protection). The specific measures are to monitor the changes of water temperature, pH and DO water quality regularly, change the water every 4 days on average, control the water level 50-80cm, wash the pond when changing water, check the growth and health status of fish, and remove the injured seedlings in time. Timely use siphon method to remove feces. If the pool water is thick and the transparency is less than 25cm, change the water in time to keep the water fresh and yellowish green.

Sampan fish is an omnivorous oral fish mainly of animal nature. seedlings eat phytoplankton or zooplankton, adult fish are mainly plant, also eat small miscellaneous fish and shrimp, and can eat artificial compound pellet feed and natural organic bait. Plant feed is the leaves of wilted melons and tubers, such as taro leaves, cassava leaves, sweet potato leaves, papaya leaves, cucumber leaves and cucumbers, pumpkins and so on.

2.1 Fish fry stage feeding and management

In order to speed up the growth of fish fry and ensure the freshness of water quality, shredded fish were mainly fed with shredded fish at the fry stage, with a feeding amount of 1.525kg / day. Half a month later, the larvae of sea bass were fed with 1.2 kg / day.

The feeding rate varies with the change of water temperature, generally 4-8%. When the water temperature is less than 25 ℃, it should be fed once every evening, and when the water temperature is more than 25 ℃, it should be fed once in the morning and once in the afternoon, and the feeding amount should be finished at 1 hour after throwing.

2.2 feeding and management of adult fish

When the fry grows to about 10cm, it is transferred to adult fish and fed with tilapia feed twice a day in the morning and afternoon, with a feeding rate of 35%.

In management, quicklime (15ppm) is used to regulate pH. In order to control the water quality, reduce the fertility and adjust the transparency, 50 silver carp were stocked.

2.3 Prevention and control of fish disease

There were no viral and bacterial fish diseases in culture, but water mildew caused by transportation injury in the early stage. After autumn, due to fat water quality and low transparency, anchor head flea disease appeared, which was sprinkled twice by trichlorfon.