Technical points of raising eel in Taishan soil pond

The eel culture model in Taishan earthen pond is an extensive culture model developed from the model of raising family fish in earthen pond. Its characteristics are: ① pond is large, generally more than 4 mu, up to 20~30 mu, developed in pieces; ② stocking density is small;③ water source is insufficient, a pool of water is cultivated, the water depth is less than 1.2 meters;④ soil quality is good, mainly loam; ④ oxygen facilities are sufficient; Sixth feeding method is full meal to the left bait; Seventh annual cultivation rate is more than 90%.

Taishan earth pond is mostly developed from reclaimed land. Its soil is mostly clay. Its water retention performance is very good. After a year or eight or nine months, except for partial evaporation, there is almost no leakage. Therefore, the whole breeding process almost does not need to supplement new water, and the water quality is extremely stable. As for how to raise a pond of eel, the technical points are as follows:

1. The eel culture pond in Taishan earth pond is pure earth pond without matching white seedling culture pond, and the eel species put into it come from Jiangsu and Fujian. In view of this situation, Taishan eel owners set up "mother pool" and "child pool." The so-called "mother pond" means that the small-sized eel species (generally between 150~200 fish/kg) cultivated on behalf of the eel are directly put into the breeding density of 20,000 ~ 30,000 fish/mu. After one cycle, the net is pulled and large-sized eels are selected and placed in so-called "daughter ponds" until commercial eels are developed. The small eel sifted was kept in the original pond, and after 2~3 times of screening, the eel tail sifted was very few. At this time, the "mother pool" can be cleaned, and the eel seed cultivation is basically completed. Why set up a "mother pool"? The significance lies in that because the number of "mother ponds" is small, the stocking density of small eel species in "mother ponds" is large, so that eel tails can be reduced to only exist in a few "mother ponds."

2. Preparation of ponds prior to stocking. After the bottom of the pond is exposed to the sun to crack (or the crack layer is pushed away by bulldozer), water is poured into the culture water level, 400kg of quicklime is used per mu to sprinkle the water in the whole pond, and the aerator is started to stir evenly. After 10~15 days, 25~ 30kg/mu of tea seed cake is used to kill wild miscellaneous fish and shellfish, etc., and after 7~10 days, 200~ 300g/mu of cypermethrin and 2~ 3kg/mu of trichlorfon are added to kill parasites and zooplankton. Under normal circumstances, after 7 to 15 days, the eel can be tested. At this time, the pool water was "mung bean green" color, and "fresh, live, tender, cool," eel species can be put into the stage immediately after feeding.

3. The eel culture in Taishan earthen pond is insufficient in water supply due to the development of pieces; the water is extracted, and the breeding cost is high. So eel owners do everything they can to shorten the breeding cycle and, when possible, raise them in one pool to produce finished products, with little change of water. In order to shorten the breeding cycle, they adopt a non-quantitative feeding method, that is, let the eel eat, the standard is to feed until the eel does not eat at each meal.① In order to prevent indigestion during the whole feeding process, a large amount of digestive enzymes are added to help eel digestion and absorption, and enough oxygenators are started to ensure sufficient dissolved oxygen.② Add a large amount of fish oil to provide part of the calories needed for eel fat growth, thus improving feed efficiency. (3) During the cultivation of small-sized eel species, oral growth promoters such as "tonic" and drugs for improving immunity were added to make eel grow healthily and rapidly.

4. Always maintain the stability of the pond water: ① Keep the pH value of the culture pond water between 8.2 and 8.8. On a sunny day, the pH value should not be lower than 8.2 in the morning, and should reach 8.8 or above in the afternoon, otherwise it should be adjusted with quicklime.② When applying the pesticide, strive to splash the whole pool after extreme dilution, so as not to cause stress reaction of eel due to excessive local concentration or instantaneous change of pool water concentration. Cultivate microecological environment dominated by green algae and keep its vitality all the time. This requires technicians to pay close attention to periodic changes in culture ponds and kill zooplankton and some aging algae at the appropriate time.④ Keep the water level of pool water at about 1.2 meters, break the "temperature jump layer" through the double mixing action of waterwheel type and spiral aerator, so as to make dissolved oxygen enter the bottom layer and reduce the generation of harmful substances. Once the epidemic occurs, it is necessary to use good medicine and insist on not draining water in order to maintain the stability of pool water.