At present, artificial eel breeding mainly purchases wild eel species from the market. If you want to raise eel successfully, you must pass the screening of eel species. When buying eel species from the market, it is necessary to select them strictly. It is best to buy eel species caught in cages and kept temporarily for less than 2 days from fishermen, while eel species caught by hook, electrocuted eel and caught by eel clips can not be used as eel species generally, but they can also be cultured artificially through careful screening and treatment.
(1) The species selection of eels is in the natural population of eels. The deep yellow spotted eels and light yellow spotted eels are the most suitable for professional breeding, while the bluish-gray eels are only suitable for fish farming in rural families as a polyculture variety for comprehensive utilization. There are also light white eels, light black eels, etc. Such eels are small in number and do not grow fast, so they are not suitable for the development of aquaculture.
(2) The eel breeding with neat specifications, strong physique, bright color, no injury, no disease and lively swimming must be selected for screening eel species. It is best to choose local eel species for breeding, and put enough at one time. It is more economical to choose smaller eel species, generally l5 per tail. 2 grams. With the delay of time, the number of selected seedlings needs to be increased, and higher breeding benefits can be obtained in that year.
(3) systematic screening method of eel species The above screening of eel species and specifications objectively reflects the quality of eel species, and there are still many uncertain factors in actual breeding, such as storage, transportation and injury. So, you have to go through the following l? Two methods were used for screening.
L. Sensory screening method: screening according to your own feelings and experience. Eel species are healthy and active, and they can raise their heads and struggle vigorously when they are caught by hand. Observe whether there is mucous membrane shedding and abnormal spots. If the body is twisted, red, the anus is red and swollen, and the tail is twisted, the eel with good quality generally moves freely under the pool bottom. The eel with good quality is the one with clear water quality in the observation pond.
2. current screening method: eels like to swim against the current, and it is normal that the water in the eel pond is spirally stirred in a certain direction with appropriate force, and the eels swim in the opposite direction (top water). If you follow the water, it is inferior to be unable to swim.
3. Flapping screening method: In view of the characteristics that wild eels are usually less disturbed, eels are packed in shallow pots during screening, and the eels with good quality jump out after patting the pots, and those who can't or don't jump are inferior eels. However, injured and parasitic eels also jump out, so they should be carefully identified.
4. Behavioral screening method: screening according to the aggregation of eels. It was observed from the shallow pool that the eels with good quality drilled to the four corners in groups, and the eels with poor vitality when swimming alone were inferior. In order to have space for observation, the density should be less than 5 kg/m2.
5. Screening method of drilling grass or holes: Put the eel into the pool for about 2 hours, and the quality of those who don't drill holes or grass is not good, and some drills don't drill the tail or will come out again. But some eels with poor quality can also drill holes.
6. Feeding screening method: The eels are fed with compound feed accounting for 2% of the total weight of eels or 3% of Tenebrio molitor or 5% of earthworms. When the temperature is greater than 2O degrees Celsius, if more than half of the feed can be eaten within 2 hours, the eels are of good quality.
7. drug soaking screening method: effective concentration, time and temperature must be mastered when soaking drugs. Salt water method is the first choice. Salt water is very irritating, so you should be careful when choosing it. If it is not good, it will kill the eel. This method can sterilize at the same time, but it can accelerate the death of inferior eel. When screening, don't put all the eels in salt water. Select by sampling. First, grab the eels by hand and put them in salt water. The concentration is: 1% of the eels? 2%, eel 3%, soaked for about 5? LO minutes. In the process of soaking, good quality eels become nervous and quiet, or exercise regularly. However, if the eel with poor quality is stimulated by salt water, the sick eel will jump wildly and its tail will become twisted and ugly. After being put into the fish pond, the eel with good quality enters the fish nest. Secondly, soak in 8xlo-6 (negative 6 power of lo) sulfate ketone for 5? LO minutes, can make the mucous membrane of inferior eel fall off.
The survival rate and yield of the eel species screened by the above method can be greatly improved. Of course, it is necessary to master the living habits of eel, the construction of eel ponds, daily management, prevention of pests and diseases, heatstroke prevention and ecological breeding, all of which are important technical measures for the success of raising eel.